WorldWideScience

Sample records for bed heat recovery

  1. Some performance characteristics of a fluidized bed heat recovery unit

    International Nuclear Information System (INIS)

    The advantages of using fluidized bed heat recovery units with diesel engines are well documented. Two of those are: significantly less tube fouling and heat transfer coefficient four to five time higher than that of conventional shell and tube heat exchangers. The high concentration of soot in the exhaust gases of diesel engines make fouling a major concern in design of any kind of heat recovery unit. In the experiment a conventional fluidized bed heat exchanger was connected to the exhaust of a diesel engine mounted on a dynamometer. With this arrangement it was possible to test the heat recovery unit under a wide range of operating conditions. The main objective of this experiment was the determination of the performance characteristics of the heat recovery unit, especially with reference to its heat transfer and fouling characteristics. (author)

  2. Application of fluidized-bed technology to the recovery of waste heat

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, G.J.; Grogan, P.J.; Evans, A.R.

    1979-08-01

    The fluidized-bed, waste-heat boiler (FBWHB) may represent a significant opportunity for industrial energy conservation. The applications of FBWHBs to the recovery of heat from waste streams are examined. Compared to other waste-heat recovery units, FBWHBs can transfer more heat per unit volume and are physically smaller - an important consideration for retrofit and construction costs. A detailed discussion of fluidized beds, including their application in waste-heat recovery and the factors affecting FBWHB design is presented. Design methodology is discussed along with a preliminary engineering design for recovering heat from a waste-gas stream, a typical FBWHB application.

  3. Avoidable and unavoidable exergy destructions of a fluidized bed coal combustor and a heat recovery steam generator

    International Nuclear Information System (INIS)

    Highlights: • Performing advanced exergy analysis of a fluidized-bed combustion for the first time. • Comparing conventional and modified exergy efficiencies of the subsystems. • Deducting inefficiencies of the system components for possible improvements. - Abstract: Advanced exergy analysis was performed using the actual operational data taken from a fluidized bed coal combustor (FBCC) and a heat recovery steam generator (HRSG) in a textile plant located at Torbalı, Izmir. First, the conventional exergy analysis of the units was carried out. The exergetic efficiencies of the units were found to be 44.2% and 46.2%, respectively. Advanced exergy analysis was then performed by splitting the exergy destructions of the units into avoidable and unavoidable parts. The avoidable exergy destruction rates of the FBCC and the HRSG were determined to be 2999 kW and 760 kW according to the measurements. Correspondingly, the exergy efficiencies were modified to 53.1% and 48.1%, respectively

  4. Fluidised bed heat exchangers

    International Nuclear Information System (INIS)

    Problems that have arisen during the initial stages of development of fluidised bed boilers in which heat transfer surfaces are immersed in fluidised solids are discussed. The very high heat transfer coefficients that are obtained under these conditions can be exploited to reduce the total heat transfer surface to a fraction of that in normal boilers. However, with the high heat flux levels involved, tube stressing becomes more important and it is advantageous to use smaller diameter tubes. One of the initial problems was that the pumping power absorbed by the fluidised bed appeared to be high. The relative influence of the fluidising velocity (and the corresponding bed area), tube diameter, tube spacing, heat transfer coefficient and bed temperature on pumping power and overall cost was determined. This showed the importance of close tube packing and research was undertaken to see if this would adversely affect the heat transfer coefficient. Pressure operation also reduces the pumping power. Fouling and corrosion tests in beds burning coal suggest that higher temperatures could be reached reliably and cost studies show that, provided the better refractory metals are used, the cost of achieving higher temperatures is not unduly high. It now remains to demonstrate at large scale that the proposed systems are viable and that the methods incorporated to overcome start up and part lead running problems are satisfactory. The promising role of these heat transfer techniques in other applications is briefly discussed

  5. Capacitively-Heated Fluidized Bed

    Science.gov (United States)

    Mchale, E. J.

    1982-01-01

    Fluidized-bed chamber in which particles in bed are capacitively heated produces high yields of polycrystalline silicon for semiconductor devices. Deposition of unrecoverable silicon on chamber wall is reduced, and amount of recoverable silicon depositing on seed particles in bed is increased. Particles also have a size and density suitable for direct handling without consolidation, unlike silicon dust produced in heated-wall chambers.

  6. Waste heat recovery system

    International Nuclear Information System (INIS)

    Full text: The Konzen in-house designed anaerobic digester system for the POME (Palm Oil Mill Effluent) treatment process is one of the registered Clean Development Mechanism (CDM) projects in Malaysia. It is an organic wastewater treatment process which achieves excellent co-benefits objectives through the prevention of water pollution and reduction of greenhouse gas emissions, which is estimated to be 40,000 to 50,000 t-CO2 per year. The anaerobic digester was designed in mesophile mode with temperature ranging from 37 degree Celsius to 45 degree Celsius. A microorganisms growth is optimum under moderately warm temperature conditions. The operating temperature of the anaerobic digester needs to be maintained constantly. There are two waste heat recovery systems designed to make the treatment process self-sustaining. The heat recovered will be utilised as a clean energy source to heat up the anaerobic digester indirectly. The first design for the waste heat recovery system utilises heat generated from the flue gas of the biogas flaring system. A stainless steel water tank with an internal water layer is installed at the top level of the flare stack. The circulating water is heated by the methane enriched biogas combustion process. The second design utilizes heat generated during the compression process for the biogas compressor operation. The compressed biogas needs to be cooled before being recycled back into the digester tank for mixing purposes. Both the waste heat recovery systems use a design which applies a common water circulation loop and hot water tank to effectively become a closed loop. The hot water tank will perform both storage and temperature buffer functions. The hot water is then used to heat up recycled sludge from 30 degree Celsius to 45 degree Celsius with the maximum temperature setting at 50 degree Celsius. The recycled sludge line temperature will be measured and monitored by a temperature sensor and transmitter, which will activate the

  7. Ventilation with heat recovery

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Svendsen, Svend

    2005-01-01

    This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...... and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain...... an acceptable efficiency. Furthermore, solutions to secure the air tightness of the building envelope are suggested. The paper does not address problems with condensate of water in the exchanger that may freeze in cold climate conditions. This complex of problem is dealt with in a separate paper....

  8. Heat recovery apparatus

    International Nuclear Information System (INIS)

    Heat transfer is a living science and technical advances are constantly being made. However, in many cases, progress is limited by the equipment that is available on the market, rather than by knowledge of the heat transfer process. A case in point is the design of economizers: in such equipment a small quantity of water (with a relatively good heat transfer coefficient) is heated by a large quantity of low-pressure gas (with an inherently low heat transfer coefficient). As a first step in design finned tubing is used to lessen the discrepancy in coefficients. From this point, it becomes apparent that the equipment consists of a small number of tubes (to maintain good velocity on the water side) of considerable length (to provide sufficient area). In the process industries the base pressure, though low, may be in the region of 0.5 bar, and there is no convenient flue in which to place the heat recovery coil. It is therefore contained in a flat-sided enclosure, which is ill-fitted to pressure containment and is therefore reinforced with a plethora of structural sections. Such inelegant construction is quite common in North America; in Europe, cylindrical containments of vast size have been supplied for the same purposes. The real shortcoming is a successful marriage of different disciplines to produce reliable and efficient heat transfer equipment suitably contained

  9. Continuous cleaning of heat exchanger with recirculating fluidized bed

    International Nuclear Information System (INIS)

    Fluidized bed heat exchangers for liquids have been studied in the United States, the Netherlands, and the Federal Republic of Germany. Between 1965 and 1970, fluidized bed heat exchangers were developed in the United States as brine heaters in seawater desalination. Furthermore, their potential in the utilization of geothermal energy was tested between 1975 and 1980. In the Netherlands, fluidized bed heat exchangers have been developed since 1973 for brine heating and heat recovery in multistage flash evaporators for seawater desalination and, since about 1980, for applications in the process industry. The authors became interested in fluidized bed heat exchangers first in 1978 in connection with wastewater evaporation. The authors emphasize that the results of all these groups were in basic agreement. They can be summarized as follows: 1. The fluidized bed will in many cases maintain totally clean surfaces and neither scaling nor fouling will occur. In cases where even a fluidized bed cannot completely prevent scaling or fouling, the thickness of the layer is controlled. In these cases stable operation maintaining acceptable overall heat transfer coefficients is possible without cleaning. 2. There are always excellent heat transfer coefficients as low superficial velocities of less than ν < 0.5 m/s. 3. The pressure losses are comparable with those in normal heat exchangers since fluidized bed heat exchangers are mostly operated at low superficial velocities. 4. Feed flow may be varied between 50 and 150% or more of the design feed flow. 5. Erosion is negligible. 6. Fluidized bed particles can be manufactured from all sorts of chemically and mechanically resistant materials, such as sand, glass, ceramics, and metals

  10. Flow boiling heat transfer in volumetrically heated packed bed

    International Nuclear Information System (INIS)

    Highlights: • The onset of nucleate boiling in the volumetrically heated packed bed is researched. • A correlation for predicting qONB is developed. • The effects on boiling heat transfer coefficient are investigated. - Abstract: The volumetrically heated packed bed has been widely utilized in modern industry. However, due to the variability and randomness of packed bed channels, flow boiling heat transfer characteristics becomes complex, and there are no published research regarding this topic. To study flow boiling heat transfer characteristics of volumetrically heated packed beds, electromagnetic induction heating method is used to heat oxidized carbon steel balls adopted to stack the packed bed, with water as coolant in the experiment. The experimental results indicate that heat flux at onset of nucleate boiling (ONB) increases as mass flux and inlet subcooling are increased. A new correlation is developed to predict the ONB heat flux qONB in volumetrically heated packed bed, the predictions by which agree well with the experimental data, and the deviation remains less than 15%. Subcooled flow boiling heat transfer coefficient (hsub) increases with increasing mass flux, and equilibrium quality is slightly affected by heat flux. The saturated flow boiling heat transfer coefficient (hsat) increases with mass flux and equilibrium quality when equilibrium quality is lower than about 0.05, while the nucleate boiling is suppressed when the equilibrium quality exceeds a certain value

  11. Fluidized bed heating process and apparatus

    Science.gov (United States)

    McHale, Edward J. (Inventor)

    1981-01-01

    Capacitive electrical heating of a fluidized bed enables the individual solid particles within the bed to constitute the hottest portion thereof. This effect is achieved by applying an A. C. voltage potential between dielectric coated electrodes, one of which is advantageously the wall of the fluidized bed rejection zone, sufficient to create electrical currents in said particles so as to dissipate heat therein. In the decomposition of silane or halosilanes in a fluidized bed reaction zone, such heating enhances the desired deposition of silicon product on the surface of the seed particles within the fluidized bed and minimizes undesired coating of silicon on the wall of the reaction zone and the homogeneous formation of fine silicon powder within said zone.

  12. Fluidized bed heat exchanger utilizing angularly extending heat exchange tubes

    Science.gov (United States)

    Talmud, Fred M.; Garcia-Mallol, Juan-Antonio

    1980-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided and includes a steam drum disposed adjacent the fluidized bed and a series of tubes connected at one end to the steam drum. A portion of the tubes are connected to a water drum and in the path of the air and the gaseous products of combustion exiting from the bed. Another portion of the tubes pass through the bed and extend at an angle to the upper surface of the bed.

  13. Rock bed heat accumulators. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Riaz, M.

    1977-12-01

    The principal objectives of the research program on rock bed heat accumulators (or RBHA) are: (1) to investigate the technical and economic feasibility of storing large amounts of thermal energy (in the tens of MWt range) at high temperature (up to 500/sup 0/C) over extended periods of time (up to 6 months) using native earth or rock materials; (2) to conduct studies to establish the performance characteristics of large rock bed heat accumulators at various power and temperature levels compatible with thermal conversion systems; and (3) to assess the materials and environmental problems associated with the operation of such large heat accumulators. Results of the study indicate that rock bed heat accumulators for seasonal storage are both technically and economically feasible, and hence could be exploited in various applications in which storage plays an essential role such as solar power and total energy systems, district and cogeneration heating systems.

  14. Zone heating for fluidized bed silane pyrolysis

    Science.gov (United States)

    Iya, Sridhar K. (Inventor)

    1987-01-01

    An improved heated fluidized bed reactor and method for the production of high purity polycrystalline silicon by silane pyrolysis wherein silicon seed particles are heated in an upper heating zone of the reactor and admixed with particles in a lower reaction zone, in which zone a silane-containing gas stream, having passed through a lower cooled gas distribution zone not conducive to silane pyrolysis, contacts the heated seed particles whereon the silane is heterogeneously reduced to silicon.

  15. Heat transfer characteristics of the fluidized bed through the annulus

    Science.gov (United States)

    Shedid, Mohamed H.; Hassan, M. A. M.

    2015-11-01

    The annular fluidized bed can be regarded as a promising technique for waste heat recovery applications. This study investigates on the determination of steady state values of the average heat transfer on the surface of the inner tube under different operating conditions that include: (1) input heat flux ranging from 557 to 1671 W/m2, (2) superficial air velocity ranging between 0.12 and 0.36 m/s, (3) initial bed height ranging from 25 to 55 cm, (4) ratio of the inner to the outer diameters ranging from 1/6 to 1/2 and Kaolin particle diameters ranging between 282 and 550 µm. The average values of the heat transfer coefficient along the inner tube (consisting of the fluidized and free board sections) are also deduced. An empirical correlation for calculating the Nusselt number is obtained for the given parameters and ranges.

  16. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39mm ID and 2.0m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum. The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  17. Boiling Heat Transfer in Circulating Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    张利斌; 李修伦

    2001-01-01

    A model is proposed to predict boiling heat transfer coefficient in a three-phase circulating fluidized bed (CFB), which is a new type of evaporation boiling means for enhancing heat transfer and preventing fouling. To verify the model, experiments are conducted in a stainless steel column with 39 mm ID and 2.0 m height, in which the heat transfer coefficient is measured for different superficial velocities, steam pressures, particle concentrations and materials of particle. As the steam pressure and particle concentrations increase, the heat transfer coefficient in the bed increases. The heat transfer coefficient increases with the liquid velocity but it exhibits a local minimum.The heat transfer coefficient is correlated with cluster renewed model and two-mechanism method. The prediction of the model is in good agreement with experimental data.

  18. Heat recovery equipment for engines

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.L.

    1977-04-01

    The recovery and use of waste heat from prime movers is an important consideration for evaluating an on-site power system, since it is the basic factor that makes possible a substantial increase in fuel-use efficiency. The equipment usually employed to recover waste heat can be categorized as: (a) shell-and-tube type heat exchangers, (b) radiator-type heat exchangers, (c) exhaust gas boilers for the generation of pressurized hot water and/or steam, (d) steam separators, and (e) combined packaged units for ebulliently cooled internal combustion piston engines. The functional requirements and cost considerations involved in applying these devices for the recovery of waste heat from various types of prime-movers considered for application in the ICES Systems Engineering Program are examined.

  19. Investigation of volumetrically heated debris bed quenching

    Energy Technology Data Exchange (ETDEWEB)

    Konovalikhin, M.J.; Sehgal, B.R. [Royal Institute of Technology, Div. of Nuclear Power Safety, Stockholm (Sweden)

    2001-07-01

    A series of experiments were conducted at RIT (Royal Institute of Technology) in which hot homogeneous and stratified particle beds were quenched by establishing a column of water onto the top of the bed and by injection of water from the bottom delivered through downcomers from the water overlayer. For this experimental program the following approach was adopted. Since corium debris have a particle size distribution and are more like sand, the debris beds were built with sand of different particle size distributions, heated with a network of thin heaters, distributed uniformly in the sand bed to produce uniform volumetric heat generation. Low porosity beds were constructed, since they are the most difficult to quench with top flooding. The primary objective was to obtain data, which will provide a phenomenological basis for assessing margins for coolability of a degraded core debris bed in the lower head of an LWR vessel as well as steam generation rate from the interactions between core debris and water. This paper summarizes the experimental results along with related analysis. (authors)

  20. Waste heat recovery retrofit project

    Energy Technology Data Exchange (ETDEWEB)

    1987-08-01

    This report provides the results of the experience gained and the guidance for the replication of a waste heat recovery system in Lac La Martre, Northwest Territories. In the summer of 1981, a new school of 1800 m {sup 2} was built, which incorporated many energy conservation features. The project demonstrates the technical and ecomomic viability of recovering the waste heat produced by the community's generator motors and using it to almost totally heat the school. Of the three diesel-electric generators which handle the total power supply for Lac La Martre, two (281 kVa and 187 kVa capacity) have been connected to the heat recovery system. The school is provided with two 159 kW capacity boilers which are sized to handle the complete heating load. The system is described, including the heat exchangers, the heat pipe between the power plant and the school, the circulating pumps and the heat metering system. Preliminary load calculations revealed the need to use both the waste heat from the generator's coolant water and the flue gas. Now that the school has operated through a whole winter season, the project can be considered a success up to this point. From an intial capital outlay of Canadian $250,000, savings for fuel of Canadian 26,000/y are now being realized, with a total payback period of 9 years. However, it must be recognized that this system requires a higher level of skill to maintain than a simple on-off system. The difficulties encountered with a similar heat recovery system which was built in Igloolik during the 1970's are briefly discussed. 45 figs., 7 tabs.

  1. Operating theatre scheduling with patient recovery in both operating rooms and recovery beds

    OpenAIRE

    Augusto, Vincent; Xie, Xiaolan; Perdomo, Viviana

    2010-01-01

    This paper investigates the impact of allowing patient recovery in the operating room when no recovery bed is available. Three types of identical resources are considered: transporters, operating rooms and recovery beds. A fixed number of patients must be planned over a term horizon, usually one or two weeks. The surgery process is modelled as follows: each patient is transported from the ward to the operating theatre. Then the patient visits an operating room for surgery operation and is tra...

  2. Study of thermal energy storage using fluidized bed heat exchangers

    Science.gov (United States)

    Weast, T. E.; Shannon, L. J.; Ananth, K. P.

    1980-01-01

    The technical and economic feasibility of fluid bed heat exchangers (FBHX) for thermal energy storage (TES) in waste heat recovery applications is assessed by analysis of two selected conceptual systems, the rotary cement kiln and the electric arc furnace. It is shown that the inclusion of TES in the energy recovery system requires that the difference in off-peak and on-peak energy rates be large enough so that the value of the recovered energy exceeds the value of the stored energy by a wide enough margin to offset parasitic power and thermal losses. Escalation of on-peak energy rates due to fuel shortages could make the FBHX/TES applications economically attractive in the future.

  3. Toward a Heat Recovery Chimney

    Directory of Open Access Journals (Sweden)

    Min Pan

    2011-11-01

    Full Text Available The worldwide population increase and subsequent surge in energy demand leads electricity producers to increase supply in an attempt to generate larger profit margins. However, with Global Climate Change becoming a greater focus in engineering, it is critical for energy to be converted in as environmentally benign a way as possible. There are different sustainable methods to meet the energy demand. However, the focus of this research is in the area of Waste Heat Recovery. The waste heat stored in the exiting condenser cooling water is delivered to the air flow through a water-air cross flow heat exchanger. A converging thermal chimney structure is then applied to increase the velocity of the airflow. The accelerated air can be used to turn on the turbine-generator installed on the top the thermal chimney so that electricity can be generated. This system is effective in generating electricity from otherwise wasted heat.

  4. Evaporative heat transfer in beds of sensible heat pellets

    Energy Technology Data Exchange (ETDEWEB)

    Arimilli, R.V.; Moy, C.A. [Univ. of Tennessee, Knoxville, TN (United States)

    1989-03-01

    An experimental study of boiling/evaporative heat transfer from heated spheres in vertical packed beds with downward liquid-vapor flow of Refrigerant-113 was conducted. Surface superheats of 1 to 50{degrees}C, mass flow rates of 1.7 to 5.6 Kg/min, sphere diameters of 1.59 and 2.54 cm, quality (i.e., mass fraction of vapor) of the inlet flow of 0.02 to 1.0, and two surface conditions were considered. Instrumented smooth and rough aluminum spheres were used to measure the heat transfer coefficients under steady state conditions. Heat transfer coefficients were independently determined for each sphere at three values three values of surface superheat. The quantitative results of this extensive experimental study are successfully correlated. The correlation equation for the boiling heat transfer coefficients is presented in terms of a homogeneous model. The correlation may be used in the development of numerical models to simulate the transient thermal performance of packed bed thermal energy storage unit while operating as an evaporator. The boiling of the liquid-vapor flow around the spheres in the packed bed was visually observed with a fiber-optic baroscope and recorded on a videotape. The visualization results showed qualitatively the presence of four distinct flow regimes. One of these occurs under saturated inlet conditions and are referred to as the Low-quality, Medium-quality, and High-quality Regimes. The regimes are discussed in detail in this paper.

  5. Heat transfer in granular beds in radiative heat supply

    Science.gov (United States)

    Teplitskii, Yu. S.; Kovenskii, V. I.

    2010-07-01

    The basic regularities of stationary heat transfer throughout the space of an infiltrated granular bed in radiative heat supply in cocurrent-flow (solar collector 1) and counterflow (solar collector 2) regimes have been investigated within the framework of a two-temperature model. The boundary layer of the third kind for the skeleton of particles at exit from the bed has been formulated; this condition allows for the degree of turbulence of the heat-transfer-agent flow. A quasihomogeneity criterion making it possible to evaluate the thermal state of a two-phase system has been introduced. The approximation dependences for calculation of the active-portion length, the bed’s resistance, the solar-collector efficiency, and the average relative phase-temperature difference have been established.

  6. Novel heat recovery systems for building applications

    OpenAIRE

    Ahmad, Mardiana Idayu

    2011-01-01

    The work presented in this thesis will explore the development of novel heat recovery systems coupled with low carbon technologies, and its integration to become one device with multifunction (building integrated heat recovery/cooling/air dehumidifier. In the first part of this thesis, an experimental performance of an individual heat recovery unit using Micro Heat and Mass Cycle Core (MHM3C) made of fibre papers with cross flow arrangement has been carried out. The unit was tested in an env...

  7. Heat transfer between a fluid and a bed of solid particles aiming the storage and recovery of solar energy; Transferencia de calor entre um fluido e um leito de particulas solidas visando a armazenagem e recuperacao de energia solar

    Energy Technology Data Exchange (ETDEWEB)

    Alencar, Soraya Lira

    1989-10-01

    The heat transfer between a fluid and a bed of particles has a great number of technological applications. This work presents experimental and analytical results of the dynamical response of the fix bed ceramic spheres parceled by air, when submitted to a step in the inlet gas temperature. The two-phase model approach was used. Based on the experimental profiles of the gas and solid temperature the characteristic time and local coefficient of heat transmission were calculated. 26 refs; 14 figs; 16 tabs

  8. Internal dust recirculation system for a fluidized bed heat exchanger

    Science.gov (United States)

    Gamble, Robert L.; Garcia-Mallol, Juan A.

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  9. Ceramic heat recuperators for industrial heat recovery

    Science.gov (United States)

    Cleveland, J. J.; Gonzalez, J. M.; Kohnken, K. H.; Rebello, W. J.

    1980-08-01

    A cordierite (magnesium aluminum silicate) recuperator was designed for relatively small furnaces with firing rates of 0.3 MM to 0.6 MM Btu/h and with exhaust gas temperatures of 1500 F to 2600 F. Five demonstration programs were performed to determine the heat transfer performance of the device, establish the energy savings by recovery, demonstrate the durability of the ceramic core, determine the operating requirements of the burners and controls with recuperation, and establish the overall system costs and payback period. The recuperator is described and results of tests and measurements, system economics, and cost performance analyses are presented. The methodology is developed and techniques for impact analysis are described. Industrial applications are implied and a process flow diagram for smelting and refining primary copper is shown.

  10. High Performance Cascading Adsorption Refrigeration Cycle with Internal Heat Recovery Driven by a Low Grade Heat Source Temperature

    OpenAIRE

    Yuki Ueda; Atsushi Akisawa; Aep Saepul Uyun; Takahiko Miyazaki

    2009-01-01

    This paper presents the performance of an advanced cascading adsorption cycle that utilizes a driven heat source temperature between 90–130 ºC. The cycle consists of four beds that contain silica gel as an adsorber fill. Two of the beds work in a single stage cycle that is driven by an external heat source, while the other two beds work in a mass recovery cycle that is driven by waste heat of sensible and adsorption heat of the high temperature cycle. The performances, in terms of the coef...

  11. Bed to wall heat transfer in supercritical water fluidized bed: Comparison with the gas–solid fluidized bed

    International Nuclear Information System (INIS)

    Supercritical water (SCW) fluidized bed is a new reactor concept for gasification of wet biomass. In this paper, the Eulerian two-fluid model based on Kinetic Theory of Granular Flow in fluidized bed was established, and the physical model of movement of single bubble up the wall was adopted. The comparison studies of particle distribution, temperature distribution and transient heat transfer characteristics between the SCW and gas–solid fluidized bed were carried out. The results show that the bubble diameter and rise velocity in SCW fluidized bed are smaller than those in gas–solid fluidized bed. With the increasing solid volume fraction near the wall, the bed-to-wall heat transfer coefficient decreases in SCW fluidized bed, while it increases in gas–solid fluidized bed. What is more, the bed-to-wall heat transfer coefficient is sensitive to superficial velocity where the solid volume fraction is low, which is different from that in gas–solid fluidized bed

  12. Granular flow and thermal performance of Moving Bed Heat Exchangers: Comparison of the Euler-Euler model with experimental results

    OpenAIRE

    Baumann, Torsten

    2014-01-01

    A moving bed heat exchanger (MBHX) is a promising technology option for efficient heat recovery from hot particles and can be used as steam generator for concentrating solar power plants with particle-based thermal energy storage. A moving bed heat exchanger is a tube bundle heat exchanger, in which a granular bulk flows downwards gravity driven while passing the heat exchanger tubes. In the tubes, a heat transfer fluid is heated up, e.g. evaporating water. For the solar specific device in...

  13. Calculation of local bed to wall heat transfer in a fluidized-bed

    International Nuclear Information System (INIS)

    Surface to bed heat transfer in a fluidized-bed largely depends upon its local and global hydrodynamical behavior including particle velocity, particle trajectory, gas velocity, and void fraction. In this study, a computer program was developed in order to calculate the local bed to wall heat transfer, by accounting for the local and global instantaneous hydrodynamics of the bed. This is accomplished by utilizing the CHEMFLUB computer program. This information at a given location is interpreted so that the most appropriate heat transfer model is utilized for each time increment. These instantaneous heat transfer coefficient for the given location. Repeating the procedure for different locations, a space average heat transfer coefficient is also calculated. This report briefly summarizes the various heat transfer models employed and gives sample computer results reporting the case study for Mickley - Trilling's experimental set-up. Comparisons with available experimental data and correlations are also provided in order to compare and evaluate the computer results

  14. Dryout heat flux experiments with deep heterogeneous particle bed

    International Nuclear Information System (INIS)

    A test facility has been constructed at Technical Research Centre of Finland (VTT) to simulate as accurately as possible the ex-vessel core particle bed in the conditions of Olkiluoto nuclear power plant. The STYX particle bed reproduces the anticipated depth of the bed and the size range of particles having irregular shape. The bed is immersed in water, creating top flooding conditions, and internally heated by an array of electrical resistance heating elements. Dryout tests have been successfully conducted at 0.1-0.7 MPa pressure for both uniformly mixed and stratified bed geometries. In all tests, including the stratified ones, the dry zone first formed near the bottom of the bed. The measured dryout heat fluxes increased with increasing pressure, from 232 kW/m2 at near atmospheric pressure to 451 kW/m2 at 0.7 MPa pressure. The data show some scatter even for the uniform bed. The tests with the stratified bed indicate a clear reduction of critical power due to the presence of a layer of small particles on top of the uniform bed. Comparison of data with various critical power (dryout heat flux) correlations for porous media shows that the most important parameter in the models is the effective particle diameter. Adiabatic debris bed flow resistance measurements were conducted to determine the most representative particle diameter. This diameter is close, but not equal, to the particle number-weighted average diameter of the bed material. With it, uniform bed data can be calculated to within an accuracy of 3-28% using Lipinski's 0-D model. In the stratified bed experiments, it appears that the top layer was partially fluidized, hence the measured critical power was significantly higher than calculated. Future experiments are being planned with denser top layer material to eliminate non-prototypic fluidization

  15. Erosion of heat exchanger tubes in fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01

    This final report describes the activities of the 3-year project entitled Erosion of Heat Exchanger Tubes In Fluidized Beds.'' which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. [times] 24in. fluidized bed, comparative wear results In a 6in. [times] 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. [times] 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. [times] 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. [times] 24in. bed and the modeling of the tube wear in the 24in. [times] 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  16. Minimum heat transfer area for Total Site heat recovery

    International Nuclear Information System (INIS)

    Highlights: • Methodology development for Total Site heat recovery with of intermediate utility. • Selection of temperature for intermediate utilities of Total Site. • Capital cost reduction for heat exchangers network design on Total Site level. • Recommendation for selection of heat exchangers design of Total Site. - Abstract: In this paper a further development of methodology for decreasing the capital cost for Total Site heat recovery by use of different utility levels is proposed. The capital cost of heat recovery system is estimated for certain temperature level of intermediate utility applying Total Site Profiles. Heat transfer area is reduced by selection of appropriate temperature of intermediate utility. Minimum of heat transfer area depends on slopes of Total Site Profiles in each enthalpy interval. This approach allows estimating the minimum of heat transfer area for heat recovery on Total Site level. Case study is performed for fixed film heat transfer coefficients of process streams and intermediate utilities. It indicates that the total heat transfer area of heat recovery can be different up to 49.15% for different utility temperatures

  17. Real heat recovery with air handling units

    Energy Technology Data Exchange (ETDEWEB)

    Roulet, C.-A. [Laboratoire d' Energie Solaire et de Physique du Batiment, Ecole Polytechnique Federale, Lausanne (Switzerland); Heidt, F.D. [University of Siegen, Siegen (Germany); Pibiri, M.-C.; Foradini, F. [E4Tech, Lausanne (Switzerland)

    2001-07-01

    More and more air handling units are equipped with heat recovery systems, with the aim of decreasing the energy use in buildings for heating and cooling. The efficiency of the heat recovery system is often used to calculate the energy saving. However, air-handling units do not always function as planned. In particular, parasitic shortcuts and leakage may decrease dramatically the efficiency of ventilation and heat recovery. In addition, these units need electrical energy for fans, which may be more precious than saved heat. Measurements, using tracer gas dilution technique have detected various malfunctions in several units.This paper addresses real energy recovery with air handling units from a theoretical point of view and presents results of measurements on 13 units. In the best three cases, the real, global heat recovery efficiency was between 60 and 70% for units having a 80% nominal efficiency. In the three worst cases, the global efficiency was less than 10%. For these cases, the heat recovery system uses more energy than it saves. (author)

  18. Rational use of energy via heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Groscurth, H.M. (Inst. fuer Energiewirtschaft und Rationelle Energieanwendung (IER), Stuttgart Univ. (Germany))

    1992-01-01

    The linear, stochastic optimization model ECCO has been developed as a computerized planning tool for case studies on integrated energy management involving heat recovery by heat exchanger networks, heat pumps and cogeneration. The procedure of stochastic optimization is described in detail. For a model city, which consists of three districts with together nearly 20,000 inhabitants and 4 industrial companies, we obtain the following results: Via heat recovery and cogeneration, the primary energy input into the energy system of the model city may be reduced by 25% compared to a status quo scenario. At the same time, the CO[sub 2]-emissions are reduced by 31% with some fuel switching from coal to natural gas being involved. Introducing waste heat recovery and cogeneration into the model city at the current low energy price level would increase the cost of the energy system by at least 41% with respect to the status quo. (orig./BWI)

  19. The heat transfer mechanisms in fluidized beds; Laemmoensiirtomekanismit leijukerroksessa

    Energy Technology Data Exchange (ETDEWEB)

    Fogelholm, C.J.; Blomster, A.M.; Kojola, H. [Helsinki Univ. of Technology, Espoo (Finland)

    1996-12-01

    The goal of the research project is to improve the accuracy of the heat transfer correlation in circulating fluidized beds and to define how the heat transfer is distributed in radiation and convection in the different parts of the fluidized bed. This will be carried out by studying the behaviour and heat transfer of the fluidized bed in the boundary layer near the wall. The total and radiative heat transfer as well as the particle concentration will be measured. Based on the data a correlation will be created. Two different measurement systems are used. The particle concentration is measured by a image-analysis system. A video camera and a Super VHS recorder are used to capture live images from the bed. The images are digitized and stored on a PC. The system has been used in previous research projects at our laboratory. In earlier projects all measurements have been carried out in cold environments. In this project the system will be modified for hot environments. The radiative heat transfer is measured by a radiative heat transfer probe connected to a PC via an A/D converter. The probe consists of a heat flow detector which is isolated from the bed by a sapphire window so that only the radiative part of the heat transfer is detected. The probe will be calibrated in a black body oven so that the effect of the conduction and the sapphire window can be separated. (author)

  20. On dryout heat flux in porous debris bed

    International Nuclear Information System (INIS)

    In the late phase of severe accident in nuclear reactors, a porous debris bed is formed in lower portion of the reactor vessel. The derbis bed in internally heated by decay heat and cooled by reflooding and/or by water present in reactor cavity. The heat removal capability from the rubble and debris bed is much less than from intact core geometries. Thus, whether the debris heats up and attacks supporting structures and generates noncondensable gases depends on the extent to which natural cooling of the debris develop. Significant cooling can be achieved by boiling within the debris. However, under some conditions, the vapourization rate will exceed the replenishing rate of inflowing liquid, and a portion of the bed will become dry. The power at which this condition is met is called incipient dryout power and the heat flux leaving the top of the bed is called the dryout flux. Dryout is considered a hydrodynamic process where, in the absence of an imposed flow, vapour and liquid flow counter currently in the porous medium. Because of the low heat transfer capability of the dry debris, the dry zone can achieve high temperatures and threaten the support and containment structure. Thus condition, that induces dryout within post-accident debris, marks a domain of greatly reduced debris coolability. In this study we have reviewed different models for prediction of dryout heat flux existing in the literature. Some numerical predictions have been made for dryout heat flux and the void fraction at which they occur

  1. Heat Transfer in a Fixed Bed of Straw Char

    DEFF Research Database (Denmark)

    Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Jensen, Anker; Jensen, Peter Arendt; Glarborg, Peter

    2003-01-01

    A model for the thermal conductivity of a straw char bed has been developed. The model extends the work of Yagi and Kunii to describe heat transfer in a bed of cylinders, using a relationship between the interparticle distance and the external porosity. To verify the model, thermal conductivity...... experimental uncertainty over the range of conditions investigated. The heat transfer model was used in a parametric study to evaluate the effect of gas flow rate, particle diameter, porosity, and temperature on the thermal conductivity in a straw char bed....

  2. Design manual. [High temperature heat pump for heat recovery system

    Energy Technology Data Exchange (ETDEWEB)

    Burch, T.E.; Chancellor, P.D.; Dyer, D.F.; Maples, G.

    1980-01-01

    The design and performance of a waste heat recovery system which utilizes a high temperature heat pump and which is intended for use in those industries incorporating indirect drying processes are described. It is estimated that use of this heat recovery system in the paper, pulp, and textile industries in the US could save 3.9 x 10/sup 14/ Btu/yr. Information is included on over all and component design for the heat pump system, comparison of prime movers for powering the compressor, control equipment, and system economics. (LCL)

  3. Heat Recovery Steam Generator by Using Cogeneration

    Directory of Open Access Journals (Sweden)

    P.Vivek, P. Vijaya kumar

    2014-01-01

    Full Text Available A heat recovery steam generator or HRSG is an energy recovery heat exchanger that recovers heat from a hot gas stream. It produces steam that can be used in a process (cogeneration or used to drive a steam turbine (combined cycle. It has been working with open and closed cycle. Both of cycles are used to increase the performance and also power on the cogeneration plant. If we are using closed cycle technology, we can recycle the waste heat from the turbine. in cogeneration plant, mostly they are using open cycle technology. additional, by using closed cycle technology, we can use the waste heat that converts into useful amount of work. In this paper, the exhaust gas will be sent by using proper outlet from cogen unit, we are using only waste heat that produce from turbine.

  4. Modeling and field observations of char bed processes in black liquor recovery boilers

    Energy Technology Data Exchange (ETDEWEB)

    Engblom, M.

    2010-07-01

    The char bed plays an important role in kraft black liquor combustion. Stable operation of the char bed promotes efficient and safe operation of the black liquor recovery boiler. It also plays a crucial role in the recovery of the pulping chemicals. Char bed operation involves controlling the char bed size and shape. Mathematical modeling based on computational fluid dynamics (CFD) haas been applied to recovery boilers for increased insights into the recovery furnace processes and to aid in the design of new boilers. So far, all CED-based char bed models reported in literature have used a fixed bed shape. This imposes restrictions on simulation of char bed burning by not considering inherently occurring changes in bed shape. In this thesis, a CED -based recovery furnace model is further developed to predict changes in bed shape. The new model is used in simulation of existing recovery boilers. The predictions of bed shape are compared with observations from real boilers. The furnace model is capable of correctly simulating the overall response of the char bed size to operational changes. This confirms the current quantitative overall understanding of char bed burning. In addition to modeling, visual observations of the char bed processes were made in this work. The observations provide validation data concerning the physical behavior of the char bed, and the findings from the observations can be used in further development of char bed models. Modeling and simulations of fundamental laboratory scale char bed experiments reported in literature are also carried out. The simulations complement the experimental data by providing detailed insights into gas phase reactions that can occur inside the gas boundary layer above a char bed. (orig.)

  5. Experimental Investigation of a Three-Bed Adsorption Refrigeration Chiller Employing an Advanced Mass Recovery Cycle

    Directory of Open Access Journals (Sweden)

    Atsushi Akisawa

    2009-07-01

    Full Text Available The performance of an advanced three-bed adsorption chiller with a mass recovery cycle has been experimentally investigated in the present study. The temperature and pressure of various components of the chiller were monitored to observe the dynamic behaviour of the chiller. The performances in terms of the coefficient of performance (COP and specific cooling power (SCP were compared with a conventional single stage. The results show that the proposed cycle produces COP and SCP values superior to those of the conventional single stage cycle for heat source temperature below 75 °C.

  6. In-Bed Accountability Development for a Passively Cooled, Electrically Heated Hydride (PACE) Bed

    International Nuclear Information System (INIS)

    A nominal 1500 STP-L PAssively Cooled, Electrically heated hydride (PACE) Bed has been developed for implementation into a new Savannah River Site tritium project. The 1.2 meter (four-foot) long process vessel contains on internal 'U-tube' for tritium In-Bed Accountability (IBA) measurements. IBA will be performed on six, 12.6 kg production metal hydride storage beds.IBA tests were done on a prototype bed using electric heaters to simulate the radiolytic decay of tritium. Tests had gas flows from 10 to 100 SLPM through the U-tube or 100 SLPM through the bed's vacuum jacket. IBA inventory measurement errors at the 95% confidence level were calculated using the correlation of IBA gas temperature rise, or (hydride) bed temperature rise above ambient temperature, versus simulated tritium inventory.Prototype bed IBA inventory errors at 100 SLPM were the largest for gas flows through the vacuum jacket: 15.2 grams for the bed temperature rise and 11.5 grams for the gas temperature rise. For a 100 SLPM U-tube flow, the inventory error was 2.5 grams using bed temperature rise and 1.6 grams using gas temperature rise. For 50 to 100 SLPM U-tube flows, the IBA gas temperature rise inventory errors were nominally one to two grams that increased above four grams for flows less than 50 SLPM. For 50 to 100 SLPM U-tube flows, the IBA bed temperature rise inventory errors were greater than the gas temperature rise errors, but similar errors were found for both methods at gas flows of 20, 30, and 40 SLPM.Electric heater IBA tests were done for six production hydride beds using a 45 SLPM U-tube gas flow. Of the duplicate runs performed on these beds, five of the six beds produced IBA inventory errors of approximately three grams: consistent with results obtained in the laboratory prototype tests

  7. Magnesium hydroxide – expanded graphite composite pellets for a packed bed reactor chemical heat pump

    International Nuclear Information System (INIS)

    The chemical heat pump is a promising technology for the recovery of waste heat from industrial processes or cogeneration systems. It can be used for storing the surplus heat during low demand periods and release it for shaving the peaks of heat demand, with a benefit for the overall system efficiency. In this work, a packed bed reactor chemical heat pump based on the dehydration and hydration of magnesium hydroxide has been investigated. Due to its high thermal conductivity, expanded graphite was mixed with magnesium hydroxide to enhance heat transfer. The composite material, named EM, was developed and tested experimentally in order to understand the effects of expanded graphite on the chemical reactions occurring in the packed bed reactor. -- Highlights: • An expanded graphite/Mg(OH)2 composite was developed for a packed bed reactor chemical heat pump. • The expanded graphite/Mg(OH)2 composite (EM) was compressed in figure of pellets. • Higher reaction rates were observed for the dehydration and hydration of EM pellets. • EM pellets showed better performance in terms of heat storage and heat output. • EM pellets were able to withstand repetitive cyclic reactions without significant failures

  8. Method of Heating a Foam-Based Catalyst Bed

    Science.gov (United States)

    Fortini, Arthur J.; Williams, Brian E.; McNeal, Shawn R.

    2009-01-01

    A method of heating a foam-based catalyst bed has been developed using silicon carbide as the catalyst support due to its readily accessible, high surface area that is oxidation-resistant and is electrically conductive. The foam support may be resistively heated by passing an electric current through it. This allows the catalyst bed to be heated directly, requiring less power to reach the desired temperature more quickly. Designed for heterogeneous catalysis, the method can be used by the petrochemical, chemical processing, and power-generating industries, as well as automotive catalytic converters. Catalyst beds must be heated to a light-off temperature before they catalyze the desired reactions. This typically is done by heating the assembly that contains the catalyst bed, which results in much of the power being wasted and/or lost to the surrounding environment. The catalyst bed is heated indirectly, thus requiring excessive power. With the electrically heated catalyst bed, virtually all of the power is used to heat the support, and only a small fraction is lost to the surroundings. Although the light-off temperature of most catalysts is only a few hundred degrees Celsius, the electrically heated foam is able to achieve temperatures of 1,200 C. Lower temperatures are achievable by supplying less electrical power to the foam. Furthermore, because of the foam s open-cell structure, the catalyst can be applied either directly to the foam ligaments or in the form of a catalyst- containing washcoat. This innovation would be very useful for heterogeneous catalysis where elevated temperatures are needed to drive the reaction.

  9. Bed-To-Wall Heat Transfer in a Supercritical Circulating Fluidised Bed Boiler

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2014-06-01

    Full Text Available The purpose of this work is to find a correlation for heat transfer to walls in a 1296 t/h supercritical circulating fluidised bed (CFB boiler. The effect of bed-to-wall heat transfer coefficient in a long active heat transfer surface was discussed, excluding the radiation component. Experiments for four different unit loads (i.e. 100% MCR, 80% MCR, 60% MCR and 40% MCR were conducted at a constant excess air ratio and high level of bed pressure (ca. 6 kPa in each test run. The empirical correlation of the heat transfer coefficient in a large-scale CFB boiler was mainly determined by two key operating parameters, suspension density and bed temperature. Furthermore, data processing was used in order to develop empirical correlation ranges between 3.05 to 5.35 m·s-1 for gas superficial velocity, 0.25 to 0.51 for the ratio of the secondary to the primary air, 1028 to 1137K for bed temperature inside the furnace chamber of a commercial CFB boiler, and 1.20 to 553 kg·m-3 for suspension density. The suspension density was specified on the base of pressure measurements inside the boiler’s combustion chamber using pressure sensors. Pressure measurements were collected at the measuring ports situated on the front wall of the combustion chamber. The obtained correlation of the heat transfer coefficient is in agreement with the data obtained from typical industrial CFB boilers.

  10. Rankine cycle waste heat recovery system

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Nelson, Christopher R.

    2015-09-22

    A waste heat recovery (WHR) system connects a working fluid to fluid passages formed in an engine block and/or a cylinder head of an internal combustion engine, forming an engine heat exchanger. The fluid passages are formed near high temperature areas of the engine, subjecting the working fluid to sufficient heat energy to vaporize the working fluid while the working fluid advantageously cools the engine block and/or cylinder head, improving fuel efficiency. The location of the engine heat exchanger downstream from an EGR boiler and upstream from an exhaust heat exchanger provides an optimal position of the engine heat exchanger with respect to the thermodynamic cycle of the WHR system, giving priority to cooling of EGR gas. The configuration of valves in the WHR system provides the ability to select a plurality of parallel flow paths for optimal operation.

  11. Rankine cycle waste heat recovery system

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Nelson, Christopher R.

    2016-05-10

    This disclosure relates to a waste heat recovery (WHR) system and to a system and method for regulation of a fluid inventory in a condenser and a receiver of a Rankine cycle WHR system. Such regulation includes the ability to regulate the pressure in a WHR system to control cavitation and energy conversion.

  12. Waste heat recovery for offshore applications

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Kandepu, Rambabu; Haglind, Fredrik

    2012-01-01

    vary in the range 20-30%. There are several technologies available for onshore gas turbines (and low/medium heat sources) to convert the waste heat into electricity. For offshore applications it is not economical and practical to have a steam bottoming cycle to increase the efficiency of electricity...... present paper, a review of the technologies available for waste heat recovery offshore is made. Further, the challenges of implementing these technologies on offshore platforms are discussed from a practical point of view. Performance estimations are made for a number of combined cycles consisting of a...

  13. Solid waste utilization: incineration with heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Boegly, W.J. Jr.

    1978-04-01

    As a part of the Integrated Community Energy Systems (ICES) Program, Technology Evaluations, this evaluation considers the potential utilization of municipal solid wastes as an energy source by use of incineration with heat recovery. Subjects covered include costs, design data, inputs and outputs, and operational problems. Two generic types of heat recovery incinerators are evaluated. The first type, called a waterwall incinerator, is one in which heat is recovered directly from the furnace using water circulated through tubes imbedded in the furnace walls. This design normally is used for larger installations (>200 tons/day). The second type, a starved-air incinerator is used mainly in smaller sizes (<100 tons/day). Burning is performed in the incinerator, and heat recovery is obtained by the use of heat exchangers on the flue gases from the incinerator. Currently there are not many installations of either type in the United States; however, interest in this form of solid-waste handling appears to be increasing.

  14. Single-phase convection heat transfer characteristics of pebble-bed channels with internal heat generation

    International Nuclear Information System (INIS)

    Graphical abstract: The core of the water-cooled pebble bed reactor is the porous channels which stacked with spherical fuel elements. The gaps between the adjacent fuel elements are complex because they are stochastic and often shift. We adopt electromagnetic induction heating method to overall heat the pebble bed. By comparing and analyzing the experimental data, we get the rule of power distribution and the rule of heat transfer coefficient with particle diameter, heat flux density, inlet temperature and working fluid's Re number. Highlights: ► We adopt electromagnetic induction heating method to overall heat the pebble bed to be the internal heat source. ► The ball diameter is smaller, the effect of the heat transfer is better. ► With Re number increasing, heat transfer coefficient is also increasing and eventually tends to stabilize. ► The changing of heat power makes little effect on the heat transfer coefficient of pebble bed channels. - Abstract: The reactor core of a water-cooled pebble bed reactor includes porous channels that are formed by spherical fuel elements. This structure has notably improved heat transfer. Due to the variability and randomness of the interstices in pebble bed channels, heat transfer is complex, and there are few studies regarding this topic. To study the heat transfer characters of pebble bed channels with internal heat sources, oxidized stainless steel spheres with diameters of 3 and 8 mm and carbon steel spheres with 8 mm diameters are used in a stacked pebble bed. Distilled water is used as a refrigerant for the experiments, and the electromagnetic induction heating method is used to heat the pebble bed. By comparing and analyzing the experimental results, we obtain the governing rules for the power distribution and the heat transfer coefficient with respect to particle diameter, heat flux density, inlet temperature and working fluid Re number. From fitting of the experimental data, we obtain the dimensionless average

  15. Sustainable Development through Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    P. S. Bundela

    2010-01-01

    Full Text Available Problem statement: Waste Heat Recovery (WHR steam Technology is a proven Technology pioneered by Japanese for cement plant and it is economically viable. Electrical Power can be generated by adopting the latest technology in this field. It used a medium to low temperature (120-350°C Turbine technology (standard thermal power plants run on steam temp-500°C. Approach: It requires treat exchangers (Hx designed for high dust load, no additional fuel is required Kymore Cement Works has proposed to install a power plant of 9 MW which will be operated with the recovered waste heat from the clinker coolers and kilns from its both clinker units. The hot air from cooler and kiln passes through the ESP is taken to the waste heat recovery exchangers. Adequate size of heat-exchangers will be located at proper locations in order to achieve optimum temperature of Thermic Oil from waste gases. Conclusion/Recommendations: This is required for optimal power yield. The hot flue gases will pass through a Heat Exchanger by which the temperature (heat of the waste gas is transferred to the internal elements of the heat exchangers which is used for heating of the thermo oil. In turn this thermal oil vaporizes the organic fluid in close loop cycle. Multi level pressure turbine system will be installed which increases usable heat content resulting in higher power output. The turbine will be run by the organic vapors to generate the electrical energy. The system of oil collection, oil transfer to the vaporizer and its recycling process will be made for the complete recycling of the thermal oil.

  16. Short review on heat recovery from exhaust gas

    Science.gov (United States)

    Jaber, Hassan; Khaled, Mahmoud; Lemenand, Thierry; Ramadan, Mohamad

    2016-07-01

    The increasing growth of energy demand leads to issues associated with energy demand reduction and propose new energy efficient solutions. Heat recovery consists the most promising solution especially in regions where renewable energy resources are not available. That is why the domain of heat recovery has shown a tremendous improvement during the recent years. On the other hand, few works have been dedicated to heat recovery from exhaust gas. This paper presents a review on heat recovery from exhaust gas. The authors propose to classify exhaust gas heat recovery systems within three different classifications that are exhaust gas temperature, utilized equipment and recovery purposes.

  17. Condensing Heat Recovery of Centrifugal Chiller

    Institute of Scientific and Technical Information of China (English)

    GONG Guang-cai; JIAO Jun-jun; WANG Li-ping; ZENG Wei

    2009-01-01

    To a kind of centrifugal water chiUer with R22 and about 1745 kW of cooling capacity.a heat exchanger was added between the outlet of compressor and original condenser to get part of or all the condensing heat.Condensing heat can be recovered by compound condensing method,which adopts air-cooling model+wa-ter-cooling model or water-cooling model+water-cooling model at the condensing side of the system.By exergy analysis and experiment research on compound condensing heat recovery of centrifugal chiller,the results are ob-tained that the capability of the whole system increases,the energy efficiency ratio (EER) becomes 3.2~5.0 from 2.2~3.4, which implies the EER increases about 1.0~1.5,the exergy efficiency increases about 10%,and the chiller runs more stably after reformation.

  18. A Computational Study of Surface to Bed Heat Transfer and Reactive Flows in Gas Fluidized Beds

    OpenAIRE

    Yusuf, Rahel

    2010-01-01

    This thesis presents the study of surface to bed heat transfer and reactive flows in dense phase gas-fluidized beds. The bulk of the thesis comprises of computational studies although some experimental work is also done in order to validate the model predictions. The computations are performed on the three dimensional, finite volume in-house code FLOTRACS-MP-3D in a Cartesian coordinate system. The in-house code is based on the Eulerian-Eulerian approach which treats the gas and solid phases ...

  19. The heat transfer mechanisms in fluidized beds; Laemmoensiirtomekanismit leijukerroksessa

    Energy Technology Data Exchange (ETDEWEB)

    Fogelholm, C.J.; Blomster, A.M.; Kojola, H. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Energy Technology and Environmental Protection

    1997-10-01

    The goal of the research project is to improve the accuracy of the heat transfer correlation in circulating fluidized beds and to define how the heat transfer is distributed in radiation and convection in the different parts of the fluidized bed. This will be carried out by studying the behaviour and the heat transfer of the fluidized bed in the boundary layer near the wall. During the project the concentration and the velocity of the sand particles are measured. The particle concentration and the particle velocity are measured by an image analysis system. A video camera and a Super VHS recorder are used to capture live images from the bed. The images are digitized and stored on a PC. The measured particle concentration was at highest slightly over 20 % on the straight wall. As expected, the velocity of the fluidizing gas had the most important role on the particle concentration. The experimental studies of the particle velocity were started last autumn 1996. The velocities of the particles were measured by using a multiple exposure technique. Afterwards the images captured were analyzed by performing a Fourier transform analysis. So far the results have been encouraging and the analyzing work will be ended this spring. (orig.)

  20. Prediction of dryout heat flux of volumetrically heated particulate beds packed with multi-size particles

    International Nuclear Information System (INIS)

    This paper presents MEWA code calculations for the experiments performed on the POMECO-HT facility to investigate the dryout heat flux of various particulate beds, with the objective to interpret the experimental data and validate the code. The code is then applied to coolability assessment for ex-vessel debris beds related to severe accident scenarios of a boiling water reactor (BWR). The characteristics of a prototypical debris bed, such as multidimensionality and multiple particle sizes are emphasized in this study. The volumetrically heated particulate beds of the POMECO-HT experiments are packed with multi-size particles and equipped with a downcomer to investigate the bottom-fed coolability by natural circulation which demands 2D simulation. The results show that the MEWA code is capable of predicting the coolability of the bed with a downcomer (2D) as well as the top-flooding bed whose dryout heat flux can also be predicted by the Reed model (1D). Given the effective particle diameter (1 mm) and porosity (0.45) defined from a few FCI tests, the ex-vessel debris beds for a BWR chosen here are coolable with varied margins: i) compared with a top-flooding bed (spreading over the entire floor of the cavity), the cylindrical configuration with an annular-gap water supply enhances the coolability comparison , but the gain is marginal since the large diameter of the bed prevents the side coolant from flowing into the center of the bed; ii) a heap-like debris bed reduces rather than improves coolability due to its considerable height and base diameter; iii) a stratified debris bed with a fine-particle layer on the top may challenge the coolability. (author)

  1. Prioritizing seagrass restoration sites: study examines predictors of seagrass bed recovery

    OpenAIRE

    Uhrin, Amy V.; Kirsch, Kevin

    2011-01-01

    Ecologic researchers are modeling the impact of vessel grounding to seagrass beds using GIS in the Florida Keys National Marine Sanctuary. The surface creation tools in the ArcGIS 3D Analyst extension help assess both the damage and recovery of these seagrass beds.

  2. Air gasification of rice husk in bubbling fluidized bed reactor with bed heating by conventional charcoal.

    Science.gov (United States)

    Makwana, J P; Joshi, Asim Kumar; Athawale, Gaurav; Singh, Dharminder; Mohanty, Pravakar

    2015-02-01

    An experimental study of air gasification of rice husk was conducted in a bench-scale fluidized bed gasifier (FBG) having 210 mm diameter and 1600 mm height. Heating of sand bed material was performed using conventional charcoal fuel. Different operating conditions like bed temperature, feeding rate and equivalence ratio (ER) varied in the range of 750-850 °C, 25-31.3 kg/h, and 0.3-0.38, respectively. Flow rate of air was kept constant (37 m(3)/h) during FBG experiments. The carbon conversion efficiencies (CCE), cold gas efficiency, and thermal efficiency were evaluated, where maximum CCE was found as 91%. By increasing ER, the carbon conversion efficiency was decreased. Drastic reduction in electric consumption for initial heating of gasifier bed with charcoal compared to ceramic heater was ∼45%. Hence rice husk is found as a potential candidate to use directly (without any processing) in FBG as an alternative renewable energy source from agricultural field. PMID:25446789

  3. Influence of mass recovery on the performance of a heat pipe type ammonia sorption refrigeration system using CaCl2/activated carbon as compound adsorbent

    International Nuclear Information System (INIS)

    The performance analyses of a sorption refrigeration system with different mass recovery processes are presented, in which compound adsorbent of CaCl2 and activated carbon is used to improve the mass and heat transfer performances of sorption bed. The heating, cooling and heat recovery processes between two sorption beds were performed by multifunction heat pipes without additional power consumption. The experimental Clapeyron diagrams showed that the cycles with mass recovery (MR), with heat and mass recoveries (HMR), and with mass and heat recoveries (MHR), have better thermodynamic performances when compared with the sorption cycle without mass recovery (MR0). The implementary order of mass recovery and heat recovery has strong influence on the efficacy of mass recovery while it has little influence on the efficacy of heat recovery. In sorption cycles with HMR and with MHR, the hot beds can be pre-cooled and cold beds can be pre-heated effectively during the switching process, and heat consumption from external heat source during desorption phase is thereby reduced. Mass recovery can enlarge cycled refrigerant mass due to the transfer of refrigerant gas between two sorption beds during mass recovery process. In comparison with sorption cycle with MR0, sorption cycles with MR, with HMR, and with MHR can generally improve the coefficient of performance (COP) and specific cooling power (SCP) by more than 20% and 16%, respectively. Especially, sorption cycle with MHR has the highest performance among different mass recovery processes due to the fact that MHR has the advantages of MR and HMR, and it can improve the COP by 46.7% when compared with the cycle with MR0

  4. Experimental study on an innovative multifunction heat pipe type heat recovery two-stage sorption refrigeration system

    International Nuclear Information System (INIS)

    An innovative multifunction heat pipe type sorption refrigeration system is designed, in which a two-stage sorption thermodynamic cycle based on two heat recovery processes was employed to reduce the driving heat source temperature, and the composite sorbent of CaCl2 and activated carbon was used to improve the mass and heat transfer performances. For this test unit, the heating, cooling and heat recovery processes between two reactive beds are performed by multifunction heat pipes. The aim of this paper is to investigate the cycled characteristics of two-stage sorption refrigeration system with heat recovery processes. The two sub-cycles of a two-stage cycle have different sorption platforms though the adsorption and desorption temperatures are equivalent. The experimental results showed that the pressure evolutions of two beds are nearly equivalent during the first stage, and desorption pressure during the second stage is large higher than that in the first stage while the desorption temperatures are same during the two operation stages. In comparison with conventional two-stage cycle, the two-stage cycle with heat recovery processes can reduce the heating load for desorber and cooling load for adsorber, the coefficient of performance (COP) has been improved more than 23% when both cycles have the same regeneration temperature of 103 deg. C and the cooling water temperature of 30 deg. C. The advanced two-stage cycle provides an effective method for application of sorption refrigeration technology under the condition of low-grade temperature heat source or utilization of renewable energy

  5. High Performance Cascading Adsorption Refrigeration Cycle with Internal Heat Recovery Driven by a Low Grade Heat Source Temperature

    Directory of Open Access Journals (Sweden)

    Yuki Ueda

    2009-11-01

    Full Text Available This paper presents the performance of an advanced cascading adsorption cycle that utilizes a driven heat source temperature between 90–130 ºC. The cycle consists of four beds that contain silica gel as an adsorber fill. Two of the beds work in a single stage cycle that is driven by an external heat source, while the other two beds work in a mass recovery cycle that is driven by waste heat of sensible and adsorption heat of the high temperature cycle. The performances, in terms of the coefficient of performance (COP and the specific cooling power (SCP, are compared with conventional cascading-without-mass-recovery and single-stage cycles. The paper also presents the effect of the adsorbent mass on performance. The results show that the proposed cycle with mass recovery produces as high of a COP as the COP that is produced by the conventional cascading cycle. However, it produces a lower SCP than that of the single-stage cycle.

  6. CFD Simulation of Infiltration Heat Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, C.R.; Sherman, M.H.

    1998-07-01

    Infiltration has traditionally been assumed to affect the energy load of a building by an amount equal to the product of the infiltration flow rate and the sensible enthalpy difference between inside and outside. Results from detailed computational fluid dynamics simulations of five wall geometries over a range of infiltration rates show that heat transfer between the infiltrating air and walls can be substantial, reducing the impact of infiltration. Factors affecting the heat recovery are leakage path length, infiltration flow rate, and wall construction. The classical method for determination of the infiltration energy load was found to over-predict the amount by as much as 95 percent and by at least 10 percent. However, the air flow paths typical of building envelopes give over-predictions at the low end of this range.

  7. Is heat recovery in air-handling units efficient?

    Energy Technology Data Exchange (ETDEWEB)

    Roulet, C.-A.; Pibiri, M.-C. [Swiss Federal Institute of Technology (EPFL), LESO-PB, Lausanne (Switzerland); Heidt, F.D. [University of Siegen, Siegen (Germany); Foradini, F. [E4Tech, Lausanne (Switzerland)

    2000-09-01

    More and more air handling units are equipped with heat recovery systems, with the aim of decreasing the energy use in buildings for heating and cooling. The design efficiency of the heat recovery system is often used to calculate the energy saving. However, parasitic shortcuts in air-handling units and leakage in the building envelope dramatically decrease the efficiency of heat recovery. In addition, the electrical energy used for fans may be more precious than saved heat. Real energy recovery was measured in 13 air-handling units. In the best three cases, the real, global heat recovery efficiency was between 60 and 70% for units having a 80% nominal efficiency. In the three worst cases, the global efficiency was less than 10%. For these cases, the heat recovery system uses more primary energy than it saves. (author)

  8. Packed bed heat storage: Continuum mechanics model and validation

    Science.gov (United States)

    Knödler, Philipp; Dreißigacker, Volker; Zunft, Stefan

    2016-05-01

    Thermal energy storage (TES) systems are key elements for various types of new power plant concepts. As possible cost-effective storage inventory option, packed beds of miscellaneous material come into consideration. However, high technical risks arise due to thermal expansion and shrinking of the packed bed's particles during cyclic thermal operation, possibly leading to material failure. Therefore, suitable tools for designing the heat storage system are mandatory. While particle discrete models offer detailed simulation results, the computing time for large scale applications is inefficient. In contrast, continuous models offer time-efficient simulation results but are in need of effective packed bed parameters. This work focuses on providing insight into some basic methods and tools on how to obtain such parameters and on how they are implemented into a continuum model. In this context, a particle discrete model as well as a test rig for carrying out uniaxial compression tests (UCT) is introduced. Performing of experimental validation tests indicate good agreement with simulated UCT results. In this process, effective parameters required for a continuous packed bed model were identified and used for continuum simulation. This approach is validated by comparing the simulated results with experimental data from another test rig. The presented method significantly simplifies subsequent design studies.

  9. Numerical Simulation of Heat Transfer in a Gas Solid Crossflow Moving Packed Bed Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    Anyuan Liu; Shi Liu; Yufeng Duan; Zhonggang Pan

    2001-01-01

    The mechanism of heat transfer in a crossfiow moving packed bed heat transfer exchanger is analyzed and a two dimensional heat transfer mathematical model has been developed based on the two fluid model (TFM) approach, in which both phases are considered to be continuous and fully interpenetrating. This model is solved by means of numerical method and the results are approximately in agreement with the experimental ones.

  10. Cleaning and Heat Transfer in Heat Exchanger with Circulating Fluidized Beds

    Science.gov (United States)

    Kang, Ho Keun; Ahn, Soo Whan; Choi, Jong Woong; Lee, Byung Chang

    2010-06-01

    Fluidized bed type heat exchangers are known to increase the heat transfer and prevent the fouling. For proper design of circulating fluidized bed heat exchanger it is important to know the effect of design and operating parameters on the bed to the wall heat transfer coefficient. The present experimental and numerical study was conducted to investigate the effects of circulating solid particles on the characteristics of fluid flow, heat transfer and cleaning effect in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which a variety of solid particles such as glass (3 mmF), aluminum (2˜3 mmF), steel (2˜2.5 mmF), copper (2.5 mmF) and sand (2˜4 mmF) were used in the fluidized bed with a smooth tube. Seven different solid particles have the same volume, and the effects of various parameters such as water flow rates, particle diameter, materials and geometry were investigated. The present experimental and numerical results showed that the flow velocity range for collision of particles to the tube wall was higher with heavier density solid particles, and the increase in heat transfer was in the order of sand, copper, steel, aluminum, and glass. This behaviour might be attributed to the parameters such as surface roughness or particle heat capacity. Fouling examination using 25,500 ppm of ferric oxide (Fe2O3) revealed that the tube inside wall is cleaned by a mild and continuous scouring action of fluidized solid particles. The fluidized solid particles not only keep the surface clean, but they also break up the boundary layer improving the heat transfer coefficient even at low fluid velocities.

  11. Branched-chain amino acid supplementation during bed rest: effect on recovery

    Science.gov (United States)

    Stein, T. P.; Donaldson, M. R.; Leskiw, M. J.; Schluter, M. D.; Baggett, D. W.; Boden, G.

    2003-01-01

    Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed rest, and a 4-day recovery period. During bed rest, dietary intake was supplemented with either 30 mmol/day each of glycine, serine, and alanine (group 1) or with 30 mmol/day each of the three BCAAs (group 2). Whole body protein synthesis was determined with U-(15)N-labeled amino acids, muscle, and selected plasma protein synthesis with l-[(2)H(5)]phenylalanine. Total glucose production and gluconeogenesis from alanine were determined with l-[U-(13)C(3)]alanine and [6,6-(2)H(2)]glucose. During bed rest, nitrogen (N) retention was greater with BCAA feeding (56 +/- 6 vs. 26 +/- 12 mg N. kg(-1). day(-1), P supplementation on either whole body, muscle, or plasma protein synthesis or the rate of 3-MeH excretion. Muscle tissue free amino acid concentrations were increased during bed rest with BCAA (0.214 +/- 0.066 vs. 0.088 +/- 0.12 nmol/mg protein, P glucose production and gluconeogenesis from alanine were unchanged with bed rest but were significantly reduced (P < 0.05) with the BCAA group in the recovery phase. In conclusion, the improved N retention during bed rest is due, at least in part, to accretion of amino acids in the tissue free amino acid pools. The amount accreted is not enough to impact protein kinetics in the recovery phase but does improve N retention by providing additional essential amino acids in the early recovery phase.

  12. Novel hot gas cleaning/heat recovery system

    Energy Technology Data Exchange (ETDEWEB)

    Grasa, G.; Wellman, R.G.; Kilgallon, P.; Simms, N.J.; Oakey, J.E. [Cranfield University, Cranfield (United Kingdom). Power Generation Technology Center

    2004-11-01

    This project was targeted at developing a novel integrated raw gas cooler and sulphur and halide removal process for gasification plant. The desulphurisation process is based on a twin fluidized bed system employing direct solids transfer between adjacent vessels. Halide removal is achieved by means of sorbent injection. The first stage of the project developed a series of mathematical models for the twin-bed desulphurisation concept. Then a 2-D cold model was designed and manufactured to demonstrate the concepts and the validity of the mathematical models produced. After a series of modifications were carried out and their effects assessed, a twin bed unit was designed and manufactured that was capable of being used initially as a 3-D cold model and then being retrofitted to an existing atmospheric pressure gaisifer. The twin bed system seems to be a promising technology for a heat exchanger system, due to the good particle flows between the two fluidized beds, and for the reduction in contaminant emissions. However, further work is required to improve the understanding of the twin-bed hydrodynamics, as well as to develop sorbents with operating temperatures that are compatible with the twin-bed concept. Two options for the twin bed system have been suggested as wroth pursuing as viable use of this technology in gasification plant design. The first involve a twin-bed gasification-heat exchange system where gas from a gasifier is fed to one vessel and heat is transferred to a second by means of re-circulating solids. The second option is a triple-bed adsorption-regeneration-heat exchange system where the gas from the gasifier is fed to a vessel and the H{sub 2}S is removed. Catalyst/sorbent is transferred to a second bed for regeneration and solids are transferred to a third vessel where heat is removed. 21 refs., 23 figs., 9 tabs.

  13. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    Weast, T.; Shannon, L.

    1980-01-01

    A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

  14. Magnetic field characteristics of electric bed-heating devices

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, B.W.; Davis, K.C.; Heimbigner, T.; Buschbom, R.L. [Pacific Northwest National Lab., Richland, WA (United States); Lee, G.M. [California State Department of Health Services, Berkeley, CA (United States); Yost, M.G. [Univ. of Washington School of Public Health, Seattle, WA (United States)

    1996-12-01

    Measurements of the flux density and spectra of magnetic fields (MFs) generated by several types of electric bed heaters (EBH) were made in order to characterize the MFs to which the fetus may be exposed in utero from the mother`s use of these devices. Data on MFs were gathered from more than 1,300 in-home and laboratory spot measurements. In-home measurements taken at seven different positions 10 cm from the EBHs determined that the mean flux density at the estimated position of the fetus relative to the device was 0.45 {micro}T (4.5 mG) for electric blankets and 0.20 {micro}T (2.0 mG) for electrically heated water beds. A rate-of-change (RC) metric applied to the nighttime segment of 24 h EMDEX-C personal-dosimeter measurements, which were taken next to the bed of volunteers, yielded an approximate fourfold to sixfold higher value for electric blanket users compared to water-bed heater users. These same data records yielded an approximate twofold difference for the same measurements when evaluated by the time-weighted-average (TWA) MF exposure metric. Performance of exposure meters was checked against standard fields generated in the laboratory, and studies of sources of variance in the in-home measurement protocols were carried out. Spectral measurements showed that the EBHs measured produced no appreciable high-frequency MFs. Data gathered during this work will be used in interpreting results from a component of the California Pregnancy Outcome Study, which evaluates the use of EBHs as a possible risk factor in miscarriage.

  15. Experimental study on single-phase convection heat transfer characteristics of pebble bed channels with internal heat generation

    International Nuclear Information System (INIS)

    The water-cooled pebble bed reactor core is the porous channels stacked with spherical fuel elements, having evident effect on enhancing heat transfer. Owing to the variability and randomness characteristics of it's interstice, pebble bed channels have a very complex heat transfer situation and have little correlative research. In order to research the heat transfer characters of pebble bed channels with internal heat source, electromagnetic induction heating method was adopted for overall heating the pebble bed which was composed of 8 mm diameter steel balls, and the internal heat transfer characteristics were researched. By comparing and analyzing the experimental data, the rule of power distribution and heat transfer coefficient with heat flux density, inlet temperature and working fluid's Re were got. According to the experimental data fitting, the dimensionless average heat transfer coefficient correlation criteria was got. The fitting results are good agreement with the experimental results within 12% difference. (authors)

  16. WASTE HEAT RECOVERY IN HEAT PUMP SYSTEMS: SOLUTION TO REDUCE GLOBAL WARMING

    Directory of Open Access Journals (Sweden)

    Y. Baradey

    2015-11-01

    Full Text Available Energy conversion technologies, where waste heat recovery systems are included, have received significant attention in recent years due to reasons that include depletion of fossil fuel, increasing oil prices, changes in climatic conditions, and global warming. For low temperature applications, there are many sources of thermal waste heat, and several recovery systems and potential useful applications have been proposed by researchers [1-4]. In addition, many types of equipment are used to recover waste thermal energy from different systems at low, medium, and high temperature applications, such as heat exchangers, waste heat recovery boiler, thermo-electric generators, and recuperators. In this paper, the focus is on waste heat recovery from air conditioners, and an efficient application of these energy resources. Integration of solar energy with heat pump technologies and major factors that affect the feasibility of heat recovery systems have been studied and reviewed as well. KEYWORDS: waste heat recovery; heat pump.

  17. Heat and Mass Transfer Enforcement of Vibrating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    ChuZhide; YangJunhong; 等

    1994-01-01

    This paper briefly introduces the development of vibrating fluidized bed at home and abroad,elaborates the vibration properties of vibrating fluidized bed.the fluidizing velocity and pressure drop of the bed layer,it also deduces the non-steady state drying dynamic equations of vibrating fluidized bed,analyzes main factors which influence the drying rate and inquires into drying rules of fixed bed and vibrating fluidized bed.

  18. Study of heat transfer between an over-bed oil burner flame and a fluidized bed during start-up: Determination of the flame to bed convection coefficient

    International Nuclear Information System (INIS)

    A study of the heat transfer processes between an over-bed burner flame and a fluidized bed during start-up as been conducted. Owing to the difficulty of estimating the flame to bed convection coefficient in an industrial boiler, convection coefficients were determined using a laboratory bench scale unit. Such convection heat transfer coefficients are obtained for 3 kg, 4 kg and 5.5 kg initial bed inventories by combining measured temperatures and flow rates with a mathematical model representing the complex energy exchange in the system. Results show that the height of the fluidized bed and its distance to the flame are an important factor in the overall heat transfer process, both by convection and radiation. For 5.5 kg, 4 kg and 3 kg initial bed inventories, the convection coefficients obtained, at the end of start-up, are 180 ± 30 W/m2 K, 150 ± 20 W/m2 K and 95 ± 10 W/m2 K respectively. The determined convection coefficients can be utilized in the future as guides in the design of start-up systems for BFB boilers. The energy analysis performed also identified the major sources of heat losses in the bubbling fluidized bed.

  19. Study of fuel cell powerplant with heat recovery

    Science.gov (United States)

    King, J. M.; Grasso, A. P.; Clausi, J. V.

    1975-01-01

    It was shown that heat can be recovered from fuel cell power plants by replacing the air-cooled heat exchangers in present designs with units which transfer the heat to the integrated utility system. Energy availability for a 40-kW power plant was studied and showed that the total usable energy at rated power represents 84 percent of the fuel lower heating value. The effects of design variables on heat availability proved to be small. Design requirements were established for the heat recovery heat exchangers, including measurement of the characteristics of two candidate fuel cell coolants after exposure to fuel cell operating conditions. A heat exchanger test program was defined to assess fouling and other characteristics of fuel cell heat exchangers needed to confirm heat exchanger designs for heat recovery.

  20. Development of a fluid bed weak base ion exchange process for the recovery of uranium

    International Nuclear Information System (INIS)

    The ability to recover uranium from leach solutions containing suspended solids using continuous counter-current fluid bed ion exchange is the key to reducing post leach recovery costs. Weak base resins offer the advantage of higher product purity over strong base resins and details of a laboratory programme are given in which the fluidisation, extraction and elution properties of a series of weak base resins were examined for their usefulness in the fluid bed contactor. A macroporous polystyrene resin selected from the laboratory tests has been tested on the pilot plant scale and it was concluded that resins of this type are suitable for use in the fluid bed contactor. These resins may therefore be considered for use in low cost recovery operations. During the pilot plant programme a simple method of predicting column operation based on laboratory scale stir tests was developed. (author)

  1. Optimal waste heat recovery and reuse in industrial zones

    International Nuclear Information System (INIS)

    Significant energy efficiency gains in zones with concentrated activity from energy intensive industries can often be achieved by recovering and reusing waste heat between processing plants. We present a systematic approach to target waste heat recovery potentials and design optimal reuse options across plants in industrial zones. The approach first establishes available waste heat qualities and reuse feasibilities considering distances between individual plants. A targeting optimization problem is solved to establish the maximum possible waste heat recovery for the industrial zone. Then, a design optimization problem is solved to identify concrete waste heat recovery options considering economic objectives. The paper describes the approach and illustrates its application with a case study. -- Highlights: → Developed a systematic approach to target waste heat recovery potentials and to design optimal recovery and reuse options across plants in industrial zones. → Five stage approach involving data acquisition, analysis, assessment, targeting and design. → Targeting optimization problem establishes the maximum possible waste heat recovery and reuse limit for the industrial zone. → Design optimization problem provides concrete waste heat recovery and reuse network design options considering economic objectives.

  2. Heat Transfer Analysis for a Winged Reentry Flight Test Bed

    Directory of Open Access Journals (Sweden)

    Antonio Viviani

    2009-09-01

    Full Text Available In this paper we deal with the aero-heating analysis of a reentry flight demonstrator helpfulto the research activities for the design and development of a possible winged ReusableLaunch Vehicle. In fact, to reduce risks in the development of next generation reusablelaunch vehicles, as first step it is suitable to gain deep design knowledge by means ofextensive numerical computations, in particular for the aero-thermal environment thevehicle has to withstand during reentry. The demonstrator under study is a reentry spaceglider, to be used both as Crew Rescue Vehicle and Crew Transfer Vehicle for theInternational Space Station. It is designed to have large atmospheric manoeuvringcapability, to test the whole path from the orbit down to subsonic speeds and then to thelanding on a conventional runway. Several analysis tools are integrated in the frameworkof the vehicle aerothermal design. Between the others, we used computational analyses tosimulate aerothermodynamic flowfield around the spacecraft and heat flux distributionsover the vehicle surfaces for the assessment of the vehicle Thermal Protection Systemdesign. Heat flux distributions, provided for equilibrium conditions of radiation at wall andthermal shield emissivity equal to 0.85, highlight that the vehicle thermal shield has towithstand with about 1500 [kW/m2] and 400 [kW/m2] at nose and wing leading edge,respectively. Therefore, the fast developing new generation of thermal protectionmaterials, such as Ultra High Temperature Ceramics, are available candidate to built thethermal shield in the most solicited vehicle parts. On the other hand, away from spacecraftleading edges, due to the low angle of attack profile followed by the vehicle duringdescent, the heat flux is close to values attainable with conventional heat shield. Also, thepaper shows that the flying test bed is able to validate hypersonic aerothermodynamicdesign database and passenger experiments, including thermal shield and

  3. Effective Heat Transfer Parameters In Beds Packed with Spherical Particles

    International Nuclear Information System (INIS)

    Effective radial thermal conductivity and wall heat transfer coefficient for packed bed of non reacted material, 4.8 mm alumina spheres, were experimentally determined at high temperatures up to 850 degree C for flow rates giving particle Reynolds numbers in the range of 10 - 220. Radial temperature profiles were measured at various axial positions. The results were analysed on the basis of a two-dimensional pseudo homogeneous non-plug flow model, where velocity profile take into account. Over these ranges both parameters, λer and αw, showed significant dependence on gas flow rates for all different wall temperatures and these dependencies were predicted well by correlations with particle Reynolds number

  4. Heat Recovery From Tail Gas Incineration To Generate Power

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, Tarek

    2010-09-15

    Many industrial processes result in tail gas wastes that must be flared or incinerated to abide with environmental guidelines. Tail gas incineration occurs in several chemical processes resulting in high-temperature exhaust gas that simply go to the stack, thus wasting all that valuable heat! This paper discusses useful heat recovery and electric power generation utilizing available heat in exhaust gas from tail gas incinerators. This heat will be recovered in a waste-heat recovery boiler that will produce superheated steam to expand in a steam turbine to generate power. A detailed cost estimate is presented.

  5. A study on Heat Transfer for Immersed Tube in Internally Circulating Fluidized Bed

    Institute of Scientific and Technical Information of China (English)

    TianWendong; HaoJinhua; 等

    1999-01-01

    Heat transfer coefficients for horizontally immersed tubes have been studied in a model of ICFB(Inter-nally Circulating Fluidized Bed).The characteristics in ICFB were found to be significantly different from those in bubbing bed.There is a flowing zone with high velocity in the heat exchange zone.The heat transfer coefficients strongly depend on the fluidized velocity in the flowing zone.The heat exchange process and suitable bed temperature can be controlled according to this feature.Based on the results of the experiments,a formulation for heat transfer has been developed.

  6. Modification of deposit formation in glass furnance heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Hempel, H.-U.; Novothy, R.; Staller, S.; Kraemer, J.

    1987-07-07

    This patent describes methods for removing deposits formed in the heat exchange tube of waste heat recovery boilers for glass furnaces in which sodium aluminum silicate fine particles are introduced into the waste gases before they enter the heat exchange tubes.

  7. Mathematical simulation of radial heat transfer in packed beds by pseudohomogeneous modeling

    Institute of Scientific and Technical Information of China (English)

    Rodrigo Béttega; Marcos Flávio Pinto Moreira; Ronaldo Guimar(a)es Corrêa; José Teixeira Freire

    2011-01-01

    Uniform flow regime and constant effective thermal conductivity inside packed beds are commonly accepted in the evaluation of the fluid dynamics and heat transfer in such systems. However, several authors have confirmed the presence of an oscillatory velocity profile caused by the effective contribution of porosity profile in the fluid dynamic behavior of packed beds, which directly influences the heat transfer inside the beds. This paper describes the application of a pseudo-homogeneous mathematical model for describing heat transfer in packed beds with oscillatory profiles of velocity and porosity, using a radius-dependent model for effective thermal conductivity kr. Several temperature profiles were obtained in a packed bed system with thermal source located on the wall. The simulated temperature and effective thermal conductivity obtained from simulations were compared with experimental data and calculation from a model based on uniform kr fitting. The results indicate that the proposed mathematical modeling was capable of better representing the heat transfer in the packed bed.

  8. Experimental analysis of an adsorption refrigerator with mass and heat-pipe heat recovery process

    International Nuclear Information System (INIS)

    Highlights: ► We develop one heat pipe type adsorption refrigerator. ► New compound adsorbent of CaCl2/activated carbon–ammonia can work more effectively. ► Combined mass recovery-heat pipe heat recovery can improve adsorption performance. ► Combined mass recovery-heat pipe heat recovery can reduce cycle time. - Abstract: A heat pipe type adsorption refrigerator system is proposed and investigated, which can be powered by solar energy or waste heat of engine. The study assesses the performance of compound adsorbent (CaCl2 and activated carbon)–ammonia adsorption refrigeration cycle with different orifice sets and different mass and heat recovery processes by experimental prototype machine. Specific cooling power (SCP) and coefficient of performance (COP) were calculated with experimental data to analyze the influences of operating condition. The results show that the jaw opening of the hand needle nozzle can influence the adsorption performance obviously and the thermostatic expansion valve (TEV) is effective in the intermediate cycle time in the adsorption refrigeration system. The SCP of the cycle with the mass-heat recovery together (combined recovery process) is superior to that of the conventional cycles with mass recovery or heat recovery independently.

  9. Experimental studies of boiling heat transfer and dryout in heat generating particulate beds in water at 1 bar

    International Nuclear Information System (INIS)

    Boiling heat transfer and dryout occurring while a liquid permeates a bed of self-heated particulate material are phenomena of relevance to reactor safety since they control the rate of heat removal from beds of core debris. This report presents results from laboratory experiments in which water was the coolant and the particulate material was metal spheres, usually tin-plated iron shot, heated by passing low voltage alternating current laterally through them. The study covered bed depths up to 200 mm, and particle diameters up to 5.0 mm. Values of dryout heat flux obtained for beds of uniform particles are consistent with those obtained elsewhere using different heating methods. Stratified beds in which a layer of fine particles rests upon a bed of coarse particles can reduce the dryout heat flux to below the level appropriate to either particle size alone, and devices which aid the flow of liquid and/or vapour in a bed can greatly increase the dryout heat flux. The data exhibit a high degree of consistency, and thus will prove to be valuable in testing theoretical models. (U.K.)

  10. Heat Transfer in a Fixed Biomass Char Bed

    DEFF Research Database (Denmark)

    Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Glarborg, P.; Jensen, A.; Arendt, P.

    2002-01-01

    A thermal conductivity model based on the Yagi and Kunii model together with a bed model was developed to describe the thermal conductivity of a straw char bed. The bed model describes the relationship between the distance between particles and the external porosity. To verify the model, thermal ...

  11. Heat Transfer in Segregated Fluidized Beds Part 2: Particle Motion and Its Effects on the Heat transfer in the Segregated Fluidized Beds

    Science.gov (United States)

    Gu, Yihua; Satoh, Isao; Saito, Takushi; Kawaguchi, Tatsuya

    In our previous paper, particle and temperature segregations in a fluidized bed of binary particle mixtures were experimentally examined, and heat transfer in the segregated fluidized bed was investigated. As the results, it was shown that the temperature segregation results mainly from low heat transfer coefficient through the interface layer, which exists between the flotsam-rich and jetsam-rich layers, and that the heat transfer coefficient increases rapidly with increasing the excess gas velocity. Following our previous paper, particle motion in the segregated fluidized bed was experimentally investigated in this paper, in order to make quantitative discussion on the relation between the heat transfer coefficient and particle motion in the interface layer. In the experiment, the Particle Imaging Velocimetry (PIV) method was applied to study the concentration and motion of particles in the segregated fluidized bed. A modified solid circulation model was built up to model the particle motion in the segregated fluidized bed. The experiment results showed that the vertical particle exchange rate of the interface layer increases with the excess gas velocity, and that the vertical heat transfer coefficient through the interface layer is mainly determined by the average particle exchange rate in the interface layer. Variations of the apparent thermal conductivity at different height in the particle layers were also determined by the vertical variation of the particle exchange rate. It was shown that the heat transfer coefficient or the thermal conductivity in the interface layer is influenced by the densities and specific heat capacities of the particles.

  12. Integrated heat recovery. Kilns - spray dryer - spray dryer

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, A.; Goncalves, V.; Vaz Serra, A.

    1992-08-01

    This work is about the operating conditions of a system for the preparation of atomized powder aiming at the improvement of its energetic efficiency in relation to the traditional processes. Alternative solutions were studied for the recovery of energy of the different gaseous effluents existing in the plant so as to improve the energetic efficiency of the drying process. The implantation of a system with pre-heating of heat-generator secondary air worth double recovery was choosen, by using high efficiency glass tubes heat-exchangers. Through such system it is intended to get a 9.5% reduction of LPG consumed in the heat-generator. (orig.).

  13. Simultaneous heat and mass transfer in packed bed brying of seeds having a mucilage coating

    Directory of Open Access Journals (Sweden)

    M. M. Prado

    2008-03-01

    Full Text Available The simultaneous heat and mass transfer between fluid phase and seeds having a mucilaginous coating was studied during packed bed drying. To describe the process, a two-phase model approach was employed, in which the effects of bed shrinkage and nonconstant physical properties were considered. The model took into account bed contraction by employing moving coordinates. Equations relating shrinkage and structural parameters of the packed bed with moisture content, required in the drying model, were developed from experimental results in thick-layer bed drying. The model verification was based on a comparison between experimental and predicted data on moisture content and temperature along the bed. Parametric studies showed that the application of correlations capable of incorporating changes in bed properties gives better data simulation. By experimental-theoretical analysis, the importance of shrinkage for a more accurate interpretation of heat and mass transfer phenomena in the drying of porous media composed of mucilaginous seeds is corroborated.

  14. Minewater heat recovery project. Final Technical report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1992-04-01

    This report consists of three sections: (1) Design, experimental testing and performance analysis of the 20-ft long DBHE (Downhole Bundle Heat Exchanger); (2) Modified design of mine water heat exchanger; and (3) Performance tests on mine water heat exchanger. Appendices summarize design calculations, discuss the scope of the work tasks, and present a diary of the progress throughout the research and development project.

  15. Simulation of exhaust gas heat recovery from a spray dryer

    International Nuclear Information System (INIS)

    This study explored various alternatives in improving the energy utilization of spray drying process through the exhaust gas heat recovery. Extensible and user-friendly simulation code was written in Visual Basic for Applications within Microsoft Excel for this purpose. The effects of process parameters were analyzed on the energy efficiency and energy saving in the industrial-scale spray drying system with exhaust gas heat recovery in an air-to-air heat exchanger and in the system with partial recirculation of exhaust air. The spray dryer is equipped with an indirect heater for heating the drying air. The maximum gains of 16% in energy efficiency and 50% in energy saving were obtained for spray drying system equipped with heat exchanger for exhaust air heat recovery. In addition, 34% in energy efficiency and 61% in energy saving for system with recirculation of exhaust air in the present range of process parameters. The high energy efficiency was obtained during drying of large amount of dilute slurry. The energy saving was increased using the large amount of hot drying air. - Highlights: • We model industrial-scale spray drying process with the exhaust gas heat recovery. • We develop an Excel VBA computer program to simulate spray dryer with heat recovery. • We examine effects of process parameters on energy efficiency and energy saving. • High energy efficiency is obtained during drying of large amount of dilute slurry. • Energy saving is increased using the large amount of hot drying air

  16. Identification of existing waste heat recovery and process improvement technologies

    Energy Technology Data Exchange (ETDEWEB)

    Watts, R.L.; Dodge, R.E.; Smith, S.A.; Ames, K.R.

    1984-03-01

    General information is provided on waste heat recovery opportunities. The currently available equipment for high- and low-temperature applications are described. Other equipment related to wasteheat recovery equipment such as components, instruments and controls, and cleaning equipment is discussed briefly. A description of the microcomputer data base is included. Suppliers of waste heat equipment are mentioned throughout the report, with specific contacts, addresses, and telephone numbers provided in an Appendix.

  17. Styrene recovery from polystyrene by flash pyrolysis in a conical spouted bed reactor.

    Science.gov (United States)

    Artetxe, Maite; Lopez, Gartzen; Amutio, Maider; Barbarias, Itsaso; Arregi, Aitor; Aguado, Roberto; Bilbao, Javier; Olazar, Martin

    2015-11-01

    Continuous pyrolysis of polystyrene has been studied in a conical spouted bed reactor with the main aim of enhancing styrene monomer recovery. Thermal degradation in a thermogravimetric analyser was conducted as a preliminary study in order to apply this information in the pyrolysis in the conical spouted bed reactor. The effects of temperature and gas flow rate in the conical spouted bed reactor on product yield and composition have been determined in the 450-600°C range by using a spouting velocity from 1.25 to 3.5 times the minimum one. Styrene yield is strongly influenced by both temperature and gas flow rate, with the maximum yield being 70.6 wt% at 500°C and a gas velocity twice the minimum one. PMID:26077230

  18. Study and Test of Cold Storage Heat Recovery Heat Pump Coupled Solar Drying Device

    Directory of Open Access Journals (Sweden)

    Min Li

    2013-05-01

    Full Text Available In this study, we design the recovery of a heat pump combined solar drying device. Then, with this device, drying experiments of aquatic product, tilapia, were conducted, indicating that the newly designed device functions are well in temperature adjusting and controlling performance and showing that drying time is closely related to energy consumption and drying conditions. Heat recovery heat pump combined solar energy drier can improve the drying quality of aquatic products, but also can greatly reduce the drying energy consumption, which provides theoretical support to the design and processing of heat recovery heat pump of refrigeration system coupled solar drying device.

  19. Mechanical ventilation with heat recovery in cold climates

    DEFF Research Database (Denmark)

    Kragh, Jesper; Rose, Jørgen; Svendsen, Svend

    2005-01-01

    Building ventilation is necessary to achieve a healthy and comfortable indoor environment, but as energy prices continue to rise it is necessary to reduce the energy consumption. Using mechanical ventilation with heat recovery reduces the ventilation heat loss significantly, but in cold climates...... like the Northern Europe or in arctic climate like in Greenland or Alaska these ventilation systems will typically face problems with ice formation in the heat exchanger. When the warm humid room air comes in contact with the cold surfaces inside the exchanger (cooled by the outside air), the moisture...... freezes to ice. The analysis of measurements from existing ventilation systems with heat recovery used in single-family houses in Denmark and a test of a standard heat recovery unit in the laboratory have clearly shown that this problem occurs when the outdoor temperature gets below approximately –5º...

  20. Experimental Investigation of a Three-Bed Adsorption Refrigeration Chiller Employing an Advanced Mass Recovery Cycle

    OpenAIRE

    Atsushi Akisawa; Yuki Ueda; Aep Saepul Uyun; Takahiko Miyazaki

    2009-01-01

    The performance of an advanced three-bed adsorption chiller with a mass recovery cycle has been experimentally investigated in the present study. The temperature and pressure of various components of the chiller were monitored to observe the dynamic behaviour of the chiller. The performances in terms of the coefficient of performance (COP) and specific cooling power (SCP) were compared with a conventional single stage. The results show that the proposed cycle produces COP and SCP values super...

  1. Measurement of the thermal conductivity and heat transfer coefficient of a binary bed of beryllium pebbles

    Energy Technology Data Exchange (ETDEWEB)

    Donne, M.D.; Piazza, G. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Neutronenphysik und Reaktortechnik; Goraieb, A.; Sordon, G.

    1998-01-01

    The four ITER partners propose to use binary beryllium pebble bed as neutron multiplier. Recently this solution has been adopted for the ITER blanket as well. In order to study the heat transfer in the blanket the effective thermal conductivity and the wall heat transfer coefficient of the bed have to be known. Therefore at Forschungszentrum Karlsruhe heat transfer experiments have been performed with a binary bed of beryllium pebbles and the results have been correlated expressing thermal conductivity and wall heat transfer coefficients as a function of temperature in the bed and of the difference between the thermal expansion of the bed and of that of the confinement walls. The comparison of the obtained correlations with the data available from the literature show a quite good agreement. (author)

  2. Quenching by top flooding of a heat generating particulate bed with gas injection at the bottom

    International Nuclear Information System (INIS)

    Continued undercooling of the core of a light water reactor can result in severe degradation of the core material. In the degraded state, the core can form a heat generating debris bed. Successful quenching of such a debris bed must be accomplished before continuous cooling can be established. In this paper, experimental results on top quenching of a particulate bed with internal heat generation are reported. The effect of gas injection at the bottom was also examined. A model which included the effect of axial conduction is proposed to predict the quench front history and temperature variation in the unquenched portion of the bed

  3. Particle-bed heat transfer studies at the Atomic Energy Establishment Winfrith (UKAEA)

    International Nuclear Information System (INIS)

    Experimental studies of boiling heat transfer and dryout in electrically heated beds of liquid-saturated particulate have been in progress at AEE Winfrith for the past four years. Results of experimental work published to date relate to water-saturated beds at a pressure of 1 bar. In recent years PWR interests have widened studies of cooling self-heated particle beds because there are both in-vessel and ex-vessel situations where particulate debris may occur during accidents which cause severe core damage. Dryout during boiling heat transfer is a relevant phenomenon in assessments of whether the debris can be adequately cooled and the damage sequence stopped, although much work is yet required to characterise the particulate core debris which may form during these low-probability accidents. This paper outlines work which has been done, or is in progress at AEE Winfrith. Topics include studies of dryout, pressure drop and vapour fraction for beds of spherical particles. Most of the data relate to water-cooled beds, but some data relate to beds cooled with a low latent-heat organic fluid. Direct electrical resistance heating has been used for most of the work, and this has been shown to be suitable for beds of uniform spheres. Work at AEE Winfrith also includes the development of dielectric heating as a means of heating beds of particles. This appears to be an excellent way of heating beds of irregular particles in a way which closely simulates decay-heating, and our progress in this area is described

  4. Erosion of heat exchanger tubes in fluidized beds. Annual report, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, E.K.; Flemmer, R.L.C.

    1991-01-01

    This final report describes the activities of the 3-year project entitled ``Erosion of Heat Exchanger Tubes In Fluidized Beds.`` which was completed at the end of 1990. Project accomplishments include the collection of a substantial body of wear data In a 24in. {times} 24in. fluidized bed, comparative wear results In a 6in. {times} 6in. fluidized bed, the development of a dragometer and the collection of a comprehensive set of drag force data in the 24in. {times} 24in. bed, Fast Fourier Transform (FFT) analysis of bubble probe data to establish dominant bubble frequencies in the 24in. {times} 24in. bed, the use of a heat flux gauge for measurement of heat transfer coefficients in the 24in. {times} 24in. bed and the modeling of the tube wear in the 24in. {times} 24in. bed. Analysis of the wear data from the 24in. square bed indicates that tube wear increases with increase in superficial velocity, and with increase in tube height. The latter effect is a result of the tubes higher up in the bed seeing greater movement of dense phase than tubes lower down In the bed. In addition, tube wear was found to decrease with increase in particle size, for constant superficial velocity. Three models of tube wear were formulated and provided acceptable prediction of wear when compared with the experimental data.

  5. Coabsorbent and thermal recovery compression heat pumping technologies

    CERN Document Server

    Staicovici, Mihail-Dan

    2014-01-01

    This book introduces two of the most exciting heat pumping technologies, the coabsorbent and the thermal recovery (mechanical vapor) compression, characterized by a high potential in primary energy savings and environmental protection. New cycles with potential applications of nontruncated, truncated, hybrid truncated, and multi-effect coabsorbent types are introduced in this work.   Thermal-to-work recovery compression (TWRC) is the first of two particular methods explored here, including how superheat is converted into work, which diminishes the compressor work input. In the second method, thermal-to-thermal recovery compression (TTRC), the superheat is converted into useful cooling and/or heating, and added to the cycle output effect via the coabsorbent technology. These and other methods of discharge gas superheat recovery are analyzed for single-, two-, three-, and multi-stage compression cooling and heating, ammonia and ammonia-water cycles, and the effectiveness results are given.  The author presen...

  6. Heat recovery from nuclear power plants

    International Nuclear Information System (INIS)

    The thermodynamic efficiency of a standard Nuclear Power Plant (NPP) is around 33%. Therefore, about two third of the heat generated by the nuclear fuel is literally wasted in the environment. Given the fact that the steam coming out from the high pressure turbine is superheated, it could be advantageously used for non electrical applications, particularly for district heating. Considering the technological improvements achieved these last years in heat piping insulation, it is now perfectly feasible to envisage heat transport over quite long distances, exceeding 200 km, with affordable losses. Therefore, it could be energetically wise to revise the modifications required on present reactors to perform heat extraction without impeding the NPP operation. In this paper, the case of a French reactor is studied showing that a large fraction of the wasted nuclear heat can be actually recovered and transported to be injected in the heat distribution network of a large city. Some technical and economical aspects of nuclear district heating application are also discussed. (author)

  7. Simulation of a high efficiency multi-bed adsorption heat pump

    International Nuclear Information System (INIS)

    Attaining high energy efficiency with adsorption heat pumps is challenging due to thermodynamic losses that occur when the sorbent beds are thermally cycled without effective heat recuperation. The multi-bed concept described here enables high efficiency by effectively transferring heat from beds being cooled to beds being heated. A simplified lumped-parameter model and detailed finite element analysis are used to simulate a sorption compressor, which is used to project the overall heat pump coefficient of performance. Results are presented for ammonia refrigerant and a nano-structured monolithic carbon sorbent specifically modified for the application. The effects of bed geometry and number of beds on system performance are explored, and the majority of the performance benefit is obtained with four beds. Results indicate that a COP of 1.24 based on heat input is feasible at AHRI standard test conditions for residential HVAC equipment. When compared on a basis of primary energy input, performance equivalent to SEER 13 or 14 are theoretically attainable with this system. - Highlights: ► A multi-bed concept for adsorption heat pumps is capable of high efficiency. ► Modeling is used to simulate sorption compressor and overall heat pump performance. ► Results are presented for ammonia refrigerant and a nano-structured monolithic carbon sorbent. ► The majority of the efficiency benefit is obtained with four beds. ► Predicted COP as high as 1.24 for cooling is comparable to SEER 13 or 14 for electric heat pumps.

  8. Mechanical ventilation with heat recovery in arctic climate

    DEFF Research Database (Denmark)

    Kragh, Jesper; Svendsen, Svend

    2005-01-01

    Mechanical ventilations systems with highly effective heat recovery units in arctic climate have problems with condensing water from the extracted humid indoor air. If the condensing water freezes to ice in the heat recovery unit, the airflow rate will quickly diminish due to the increasing press...... defrosting itself. Nevertheless, extra heating is still necessary in very cold periods to avoid draft for occupants.......Mechanical ventilations systems with highly effective heat recovery units in arctic climate have problems with condensing water from the extracted humid indoor air. If the condensing water freezes to ice in the heat recovery unit, the airflow rate will quickly diminish due to the increasing...... pressure drop. Preheating the inlet air (outdoor air) to a temperature just above 0ºC is typically used to solve the problem. To minimize the energy cost, a more efficient solution to the problem is therefore desirable. In this project a new design of a heat recovery unit has been developed to the low...

  9. A safety review of the NRU effluent heat recovery project

    International Nuclear Information System (INIS)

    The NRU effluent heat recovery project diverts heated effluent water from the NRU process effluent weir and distributes the water for various heating applications in both the inner and active area at Chalk River Nuclear Laboratories (CRNL). The dominant hazard of the system operation is from leakage of tritiated heavy water from the reactor heavy water system into the light water system and the subsequent contamination of the steam system. Protective features include continuous leakage monitoring and automatic isolation of the recovery system. Modelling of the worst case accident, predicts a dose equivalent from tritium in steam humidification of about 26 mrem (260 μSv). The operation of the heat recovery project does not present an unacceptable risk to CRNL personnel

  10. Exhaust bypass flow control for exhaust heat recovery

    Science.gov (United States)

    Reynolds, Michael G.

    2015-09-22

    An exhaust system for an engine comprises an exhaust heat recovery apparatus configured to receive exhaust gas from the engine and comprises a first flow passage in fluid communication with the exhaust gas and a second flow passage in fluid communication with the exhaust gas. A heat exchanger/energy recovery unit is disposed in the second flow passage and has a working fluid circulating therethrough for exchange of heat from the exhaust gas to the working fluid. A control valve is disposed downstream of the first and the second flow passages in a low temperature region of the exhaust heat recovery apparatus to direct exhaust gas through the first flow passage or the second flow passage.

  11. ASHRAE's new Chiller Heat Recovery Application Guide

    Energy Technology Data Exchange (ETDEWEB)

    Dorgan, C.B.; Dorgan, C.E.

    2000-07-01

    The new Chiller Heat Recovery Application Guide, published by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE), provides a comprehensive reference manual on the options available for chiller heat recovery. The information in the guide will assist engineers, owners, and system operators in evaluating the potential of integrating chiller heat recovery into their cooling and heating systems. The primary focus is on new construction and applications where a chiller is being replaced due to inefficiency, high operating and maintenance (O and M) costs, or elimination of refrigerants containing ozone-depleting chemicals known as CFC/HCFCs. While chiller systems for commercial buildings are the primary focus of the guide, the information and procedures also apply to industrial heat pumps. The function of this paper is to highlight key information contained in the guide, including the major benefits of chiller heat recovery, primary candidates, and application procedures. A description of the guide's general format and contents is also provided.

  12. Experimental investigation of thermal conductivity coefficient and heat exchange between fluidized bed and inclined exchange surface

    OpenAIRE

    Stojanovic, B.; Janevski, J.; M. Stojiljkovic

    2009-01-01

    The paper presents experimental research of thermal conductivity coefficients of the siliceous sand bed fluidized by air and an experimental investigation of the particle size influence on the heat transfer coefficient between fluidized bed and inclined exchange surfaces. The measurements were performed for the specific fluidization velocity and sand particle diameters d p=0.3, 0.5, 0.9 mm. The industrial use of fluidized beds has been increasing rapidly in the past 20 years owing to their us...

  13. Experimental studies on heat transfer and pressure drop in pebble bed test facility

    International Nuclear Information System (INIS)

    Indian program for development of high temperature reactor and its utilization to supply process heat aimed to develop alternate fuel carrier to substitute petroleum based transport fuel, which has very small reserves in India and results in large import bills. Hydrogen is an attractive energy carrier for transport applications. It can be produced by splitting water which requires either electricity or process heat at high temperatures or both depending upon the process selected. BARC is carrying out design of a 600 MWth reactor capable of supplying process heat at around 1000 °C as required for hydrogen production. For this reactor various design options with respect to fuel configurations, such as prismatic bed and pebble bed were considered for thermal hydraulics analysis. Coolant options such as molten lead and molten salt were analyzed. Studies carried out indicate selection of pebble bed reactor core with molten salt as coolant. Thermal-hydraulic studies are required for pebble bed reactor. With this in view, a pebble bed test facility has been setup to study the heat transfer and pressure drop in pebble bed. Water is used as a working medium for the facility. The paper deals with the description of the pebble bed test facility and the experimental results of heat transfer and pressure drop. It also deals with the assessment of correlations for heat transfer and pressure drop in pebble bed geometry. Pressure drop experiments in the pebble bed test facility have been performed for Raynolds number ranges from 3000-12000. Various pressure drop correlations have been compared with the experimental data. It has been found that that the correlation given by Leva et. al. matches well with the experimental data. Various heat transfer correlations have also been compared. Heat transfer experiments are nearing completion

  14. Dryout heat flux and flooding phenomena in debris beds consisting of homogeneous diameter particles

    International Nuclear Information System (INIS)

    Since the TMI-2 accident, which occurred in 1979, necessity of understanding phenomena associated with a severe accident have been recognized and researches have been conducted in many countries. During a severe accident of a light water reactor, a debris bed consisting of the degraded core materials would be formed. Because the debris bed continues to release decay heat, the debris bed would remelt when the coolable geometry is not maintained. Thus the degraded core coolability experiments to investigate the influence of the debris particle diameter and coolant flow conditions on the coolability of the debris bed and the flooding experiments to investigate the dependence of flooding phenomena on the configuration of the debris bed have been conducted in JAERI. From the degraded core coolability experiments, the following conclusions were derived; the coolability of debris beds would be improved by coolant supply into the beds, Lipinski's 1-dimensional model shows good agreement with the measured dryout heat flux for the beds under stagnant and forced flow conditions from the bottom of the beds, and the analytical model used for the case that coolant is fed by natural circulation through the downcomer reproduces the experimental results. And the following conclusions were given from the flooding experiments ; no dependence between bed height and the flooding constant exists for the beds lower than the critical bed height, flooding phenomena of the stratified beds would be dominated by the layer consisting of smaller particles, and the predicted dryout heat flux by the analytical model based on the flooding theory gives underestimation under stagnant condition. (author)

  15. Study and Test of Cold Storage Heat Recovery Heat Pump Coupled Solar Drying Device

    OpenAIRE

    Min Li; Xiao-Qiang Jiang; Bao-Chuan Wu

    2013-01-01

    In this study, we design the recovery of a heat pump combined solar drying device. Then, with this device, drying experiments of aquatic product, tilapia, were conducted, indicating that the newly designed device functions are well in temperature adjusting and controlling performance and showing that drying time is closely related to energy consumption and drying conditions. Heat recovery heat pump combined solar energy drier can improve the drying quality of aquatic products, but also can gr...

  16. Use of photovoltaics for waste heat recovery

    Science.gov (United States)

    Polcyn, Adam D

    2013-04-16

    A device for recovering waste heat in the form of radiated light, e.g. red visible light and/or infrared light includes a housing having a viewing window, and a photovoltaic cell mounted in the housing in a relationship to the viewing window, wherein rays of radiated light pass through the viewing window and impinge on surface of the photovoltaic cell. The housing and/or the cell are cooled so that the device can be used with a furnace for an industrial process, e.g. mounting the device with a view of the interior of the heating chamber of a glass making furnace. In this manner, the rays of the radiated light generated during the melting of glass batch materials in the heating chamber pass through the viewing window and impinge on the surface of the photovoltaic cells to generate electric current which is passed onto an electric load.

  17. Heat transfer in packed beds at low Reynolds number. Final report

    International Nuclear Information System (INIS)

    Results from an experimental investigation of heat transfer in packed beds of low thermal conductivity particles is presented. At low Reynolds number flows through beds of fine particles the gas temperature and solids temperature differ substantially. An analytical model is proposed which treats this mechanism and is consistent with experimental results. A test apparatus was constructed and experimental results were obtained using air flowing through packed beds of sodium chloride and calcium chloride. Four heat transfer parameters were identified; bed thermal conductivity, heat transfer coefficient between the interstitial gas and the solids, and two heat transfer coefficients for the coolant tubes; one between the coolant tubes and the interstitial gas and one between the coolant tubes and the solid particles. Each coefficient is presented in terms of a single correlating parameter. A comparison between the analytical model and the test data for selected cases is also presented

  18. Cooling of an internal-heated debris bed with fine particles

    International Nuclear Information System (INIS)

    In this paper, an analytical model on dryout heat flux of ex-vessel debris beds with fines particles under top flooding conditions has been developed. The parametric study is performed on the effect of the stratification of the debris beds on the dryout heat flux. The calculated results show that the stratification configuration of the debris beds with smaller particles and lower porosity layer resting on the top of another layer of the beds has profound effect on the dryout heat flux for the debris beds both with and without a downcomer. The enhancement of the dryout heat flux by the downcomer is significant. The efficiency of the single downcomer on the enhancement of the dryout heat flux is also analyzed. This, in general, agrees well with experimental data. The model is also employed to perform the assessment on the coolability of the ex-vessel debris bed under representative accidental conditions. One conservative case is chosen, and it is found that the downcomer could be efficient measure to cool the debris bed and hence terminate the severe accident. (authors)

  19. Natural Ventilation with Heat Recovery: A Biomimetic Concept

    Directory of Open Access Journals (Sweden)

    Zulfikar A. Adamu

    2015-05-01

    Full Text Available In temperate countries, heat recovery is often desirable through mechanical ventilation with heat recovery (MVHR. Drawbacks of MVHR include use of electric power and complex ducting, while alternative passive heat recovery systems in the form of roof or chimney-based solutions are limited to low rise buildings. This paper describes a biomimetic concept for natural ventilation with heat recovery (NVHR. The NVHR system mimics the process of water/mineral extraction from urine in the Loop of Henle (part of human kidney. Simulations on a facade-integrated Chamber successfully imitated the geometry and behaviour of the Loop of Henle (LoH. Using a space measuring 12 m2 in area and assuming two heat densities of 18.75 W/m2 (single occupancy or 30 W/m2 (double occupancy, the maximum indoor temperatures achievable are up to 19.3 °C and 22.3 °C respectively. These come with mean relative ventilation rates of 0.92 air changes per hour (ACH or 10.7 L·s−1 and 0.92 ACH (11.55 L·s−1, respectively, for the month of January. With active heating and single occupant, the LoH Chamber consumes between 65.7% and 72.1% of the annual heating energy required by a similar naturally ventilated space without heat recovery. The LoH Chamber could operate as stand-alone indoor cabinet, benefitting refurbishment of buildings and evading constraints of complicated ducting, external aesthetic or building age.

  20. Performance analysis of cylindrical metal hydride beds with various heat exchange options

    International Nuclear Information System (INIS)

    Highlights: • 3D numerical model for the comparison of H2 uptake performances in MH reactors. • 4 options of heat exchange between heat transfer fluid and MH in cylindrical reactor compared. • Straight tube internal heat exchanger. • Helical coil internal heat exchanger. • External heat exchange without and with transversal fins in the MH reactor. - Abstract: A 3D numerical heat-and-mass transfer model was used for the comparison of H2 uptake performances of powdered cylindrical MH beds comprising MmNi4.6Al0.4 hydrogen storage material. The considered options of heat exchange between the MH and a heat transfer fluid included internal cooling using straight (I) or helically coiled (II) tubing, as well as external cooling of the MH bed without (III) and with (IV) transversal fins. The dynamic performances of these layouts were compared based on the numerical simulation. The effect of heat transfer coefficient was also analysed

  1. Performance investigation of a cogeneration plant with the efficient and compact heat recovery system

    KAUST Repository

    Myat, Aung

    2011-10-03

    This paper presents the performance investigation of a cogeneration plant equipped with an efficient waste heat recovery system. The proposed cogeneration system produces four types of useful energy namely: (i) electricity, (ii) steam, (iii) cooling and (iv) dehumidification. The proposed plant comprises a Capstone C30 micro-turbine which generates 24 kW of electricity, a compact and efficient waste heat recovery system and a host of waste heat activated devices namely (i) a steam generator, (ii) an absorption chiller, (iii) an adsorption chiller and (iv) a multi-bed desiccant dehumidifier. The numerical analysis for the host of waste heat recovery system and thermally activated devices using FORTRAN power station linked to powerful IMSL library is performed to investigate the performance of the overall system. A set of experiments, both part load and full load, of micro-turbine is conducted to examine the electricity generation and the exhaust gas temperature. It is observed that energy utilization factor (EUF) could achieve as high as 70% while Fuel Energy Saving Ratio (FESR) is found to be 28%.

  2. Numerical simulation and theoretical analysis of heat transfer in a moving packed bed with the local internal heat source

    International Nuclear Information System (INIS)

    Highlights: • The correlation between the particle velocity and the outlet temperature of the channel of moving packed beds were obtained. • The total radial conductive heat flow was smaller and that was only 1–4% of the heating power. • The temperature maximum was located the heating zone outlet. • The temperature in the channel decreased with the particle velocity increasing. - Abstract: The particle velocity has a major influence on heat transfer in a channel of moving packed beds with internal energy source. The outlet temperatures of the channel and the heated zone were calculated by theoretical correlations. These correlations between the particle velocity and the outlet temperature were obtained based on the basic principles of heat transfer. The theoretical analysis indicated that the outlet temperatures of the channel and the heated zone decreased as the particle velocity decreased. Numerical simulations of a three-dimensional moving packed bed model were performed to investigate the effect of particle velocity on the temperature distribution and heat transfer. Good agreement was obtained between numerical results and the theoretical correlations. The temperature field and heat transfer of the channel of moving packed beds with the internal energy source were predicted and analysed. Temperature distributions along the radius and the z-direction for various particle velocities were compared including the outlet temperature and borderline temperature of the heated zone, the outlet temperature and the centre temperature of the channel. The results showed that the particle velocity was the decisive factor for the heat transfer and temperature distribution in the channel. The total radial conductive heat flow through the channel wall was only 1–4% of the heating power and decreased as the particle velocity increased. The vast majority of heat flow continuously kept moving downward with the particles. The outlet temperatures of the heated zone and

  3. Heat Transfer Characteristics of Calcined Petroleum Coke in Waste Heat Recovery Process

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    2016-01-01

    Full Text Available This paper reports the results of heat transfer characteristics of calcined petroleum coke in waste heat recovery process. The model of heat exchanger was set up. The model has been used to investigate the effects of porosity (0.58 to 0.79, equivalent heat conductivity coefficient (0.9 to 1.1, and equivalent specific heat (0.9 to 1.1. The calculated values of calcined petroleum coke temperature showed good agreement with the corresponding available experimental data. The temperature distribution of calcined petroleum coke, the calcined petroleum coke temperature at heat exchanger outlet, the average heat transfer coefficient, and the heat recovery efficiency were studied. It can also be used in deriving much needed data for heat exchanger designs when employed in industry.

  4. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2015-09-01

    Full Text Available This paper focuses on assessment of the effect of flue gas recirculation (FGR on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  5. Nuclear-enhanced geothermal heat recovery

    International Nuclear Information System (INIS)

    This report proposes the testing of an abandoned drill well for the disposal of spent nuclear fuel rods. The well need not be in a geothermal field, since the downhole assembly takes advantage of only the natural thermal gradient. The water in the immediate vicinity of the fuel will be chemically treated for corrosion resistance. Above this will be a long column of viscous fluid insoluble in water, to act as a fluid barrier. The remainder of the well bore, up to the surface, will be the working fluid for the power turbine at the surface. There will be a low-pressure region in the immediate vicinity of the fuel, encouraging the flashing of steam. Due to the low level of heat emitted by the fuel rods, the radioactive material will be surrounded by a secondary casing that will reduce the water it contacts directly, thus causing it to heat up quickly and to maximize the steam-generating process, and the formation of air nuclides. These will percolate upward through the viscous column where steadily decreasing pressure causes expansion. The nuclear fuel's thermal energy will have been transferred through the high radioactive zone as pressure, then it will flash to steam and heat the water in the top of the wellbore. The drill well, a minimum of 10,000 ft. in depth, will naturally heat any circulating fluid. The fuel is not used as a thermal source, but only to produce a few spontaneous bubbles, sufficient to increase the fluid pressure by expansion as it rises in the wellbore. The additional thermal energy from the nuclear source will superheat the water for use in the power-generation apparatus at the surface. This equipment, operating on very-low radioactive fluid, will be protected by a secondary containment. The typical drill well is ideally suited for the insertion of spent fuel rods, which are smaller than downhole tools and instrumentation regularly installed in production wells

  6. Characteristics of convective heat transport in a packed pebble-bed reactor

    International Nuclear Information System (INIS)

    Highlights: • A fast-response heat transfer probe has been developed and used in this work. • Heat transport has been quantified in terms of local heat transfer coefficients. • The method of the electrically heated single sphere in packing has been applied. • The heat transfer coefficient increases from the center to the wall of packed bed. • This work advancing the knowledge of heat transport in the studied packed bed. - Abstract: Obtaining more precise results and a better understanding of the heat transport mechanism in the dynamic core of packed pebble-bed reactors is needed because this mechanism poses extreme challenges to the reliable design and efficient operation of these reactors. This mechanism can be quantified in terms of a solid-to-gas convective heat transfer coefficient. Therefore, in this work, the local convective heat transfer coefficients and their radial profiles were measured experimentally in a separate effect pilot-plant scale and cold-flow experimental setup of 0.3 m in diameter, using a sophisticated noninvasive heat transfer probe of spherical type. The effect of gas velocity on the heat transfer coefficient was investigated over a wide range of Reynolds numbers of practical importance. The experimental investigations of this work include various radial locations along the height of the bed. It was found that an increase in coolant gas flow velocity causes an increase in the heat transfer coefficient and that effect of the gas flow rate varies from laminar to turbulent flow regimes at all radial positions of the studied packed pebble-bed reactor. The results show that the local heat transfer coefficient increases from the bed center to the wall due to the change in the bed structure, and hence, in the flow pattern of the coolant gas. The findings clearly indicate that one value of an overall heat transfer coefficient cannot represent the local heat transfer coefficients within the bed; therefore, correlations are needed to

  7. Design of expanded bed supports for the recovery of plasmid DNA by anion exchange adsorption

    DEFF Research Database (Denmark)

    Theodossiou, Irini; Søndergaard, M.; Thomas, Owen R. T.

    In this study we detail the rational design of new chromatographic adsorbents tailored for the capture of plasmid DNA. Features present on current chromatographic supports that can significantly enhance plasmid binding capacity have been identified in packed bed chromatography experiments and...... sensitivity to inter-particle bridging by nucleic acid polymers, gave low DNA recoveries (<37%) and proved difficult to regenerate. In contrast, few operational difficulties were experienced with the diethylaminoethyl-linked prototype adsorbent and successful high capacity (>0.8 mg ml(-1)) capture of plasmid...... DNA from crude neutralised E. coli lysate was demonstrated....

  8. Nuclear-enhanced geothermal heat recovery

    International Nuclear Information System (INIS)

    This paper proposes the testing of an abandoned drill well for the disposal of spent nuclear fuel rods. The well will have no hydrocarbons subject to contamination at any open hole depth. There is incentive for companies to find some productive use of plugged and abandoned prospects, to recover a part of their investment in the drilling, testing and completion of the wells. Further controls will be in effect to minimize the escape of radiation at the source downhole. The fuel rods will be encased in an epoxy compound that will also improve structural stability while it is being lowered downhole. The water in the immediate vicinity of the fuel will be chemically treated for corrosion resistance. Above this will be a long column of viscous fluid insoluble in water, to act as a fluid and radiation barrier. The remainder of the well bore, up to the surface, will be the working fluid for the power turbine at the surface. There will be a low-pressure region in the immediate vicinity of the fuel, encouraging the flashing of steam. Due to the low level of heat emitted by the fuel rods, the radioactive material will be surrounded by a secondary casing that will reduce the water it contacts directly, thus causing it to heat up quickly and to maximize the steam-generating process, and the formation of air nuclides. These will percolate upward through the viscous column where steadily decreasing pressure causes expansion of the air particles. The nuclear fuel's thermal energy will have been transferred through the high radioactive zone as pressure, then it will flash to steam and heat the water in the top of the wellbore. The drill well, a least 10,000 ft. in depth, will naturally heat any circulating fluid. The thermal energy from the nuclear source will superheat the water for use in the power-generation apparatus at the surface. This equipment, operating on very-low radioactive fluid, will be protected by a secondary containment

  9. A Small Power Recovery Expander for Heat Pump COP Improvement

    OpenAIRE

    Ferrara, G.; Ferrari, L.; D. Fiaschi; Galoppi, G.; Karellas, S.; Secchi, R; Tempesti, D.

    2015-01-01

    Heat pumps are becoming more and more applied for heating, due to their possibility of working as cooling systems in the summer period. However, up to now, recovery of expansion work in small system has not been considered as a viable solution, because of the limited amount of recoverable energy and of difficulties in designing and operating a two-phase flow expander. The idea here presented is to investigate the application of a radial piston machine, adapted from oleodynamic motor design...

  10. Inhibition and recovery of nitrification in treating real coal gasification wastewater with moving bed biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    Huiqiang Li; Hongjun Han; Maoan Du; Wei Wang

    2011-01-01

    Moving bed biofilm reactor (MBBR) was used to treat real coal gasification wastewater.Nitrification of the MBBR was inhibited almost completely during start-up period.Sudden increase of influent total NH3 concentration was the main factor inducing nitrification inhibition.Increasing DO concentration in the bulk liquid (from 2 to 3 mg/L) had little effect on nitrification recovery.Nitrification of the MBBR recovered partially by the addition of nitrifying sludge into the reactor and almost ceased within 5 days.Nitrification ratio of the MBBR achieved 65% within 12 days by increasing dilute ratio of the influent wastewater with tap water.The ratio of nitrification decreased to 25% when infiuent COD concentration increased from 650 to 1000 mg/L after nitrification recovery and recovered 70%for another 4 days.

  11. Heat-transfer characteristics of flowing and stationary particle-bed-type fusion-reactor blankets

    International Nuclear Information System (INIS)

    The heat-transfer characteristics of flowing and stationary packed-particle beds have recently become of interest in connection with conceptual designs of fusion reactor blankets. A detailed literature survey has shown that the processes taking place in such beds are not fully understood despite their widespread use in the chemical industry and other engineering disciplines for more than five decades. In this study, two experimental investigations were pursued. In the first, a heat-transfer loop was constructed through which glass microspheres were allowed to flow by rgravity at controlled rates through an electrically heated stainless steel tubular test section. In the second, an annular packed bed was constructed in which heat was applied through the outer wall by electric heating of a stainless steel tube. Cooling occurred at the inner wall of the annular bed by flowing air through the central tube. A second air stream was allowed to flow through the voids of the packed bed. An error-minimization technique was utilized in order to obtain the two-dimensional one-parameter effective conductivity for the bed by comparing the experimental and theoretically predicted temperature profiles. Experiments were conducted for various modified Reynolds numbers less than ten

  12. Heat-transfer characteristics of flowing and stationary particle-bed-type fusion-reactor blankets

    Energy Technology Data Exchange (ETDEWEB)

    Nietert, R.E.

    1983-02-01

    The heat-transfer characteristics of flowing and stationary packed-particle beds have recently become of interest in connection with conceptual designs of fusion reactor blankets. A detailed literature survey has shown that the processes taking place in such beds are not fully understood despite their widespread use in the chemical industry and other engineering disciplines for more than five decades. In this study, two experimental investigations were pursued. In the first, a heat-transfer loop was constructed through which glass microspheres were allowed to flow by rgravity at controlled rates through an electrically heated stainless steel tubular test section. In the second, an annular packed bed was constructed in which heat was applied through the outer wall by electric heating of a stainless steel tube. Cooling occurred at the inner wall of the annular bed by flowing air through the central tube. A second air stream was allowed to flow through the voids of the packed bed. An error-minimization technique was utilized in order to obtain the two-dimensional one-parameter effective conductivity for the bed by comparing the experimental and theoretically predicted temperature profiles. Experiments were conducted for various modified Reynolds numbers less than ten.

  13. Waste heat recovery technologies for offshore platforms

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Benato, Alberto; Scolari, E.; Haglind, Fredrik; Stoppato, Anna

    2014-01-01

    to attain optimal designs for each bottoming unit by selecting specific functions tailored to the oil and gas sector, i.e. yearly CO2 emissions, weight and economic revenue. The test case is the gas turbine-based power system serving an offshore platform in the North Sea. Results indicate that the...... expander and of the primary heat exchanger, organic Rankine cycle turbogenerators appear thus to be the preferred solution to abate CO2 emissions and pollutants on oil and gas facilities. As a practical consequence, this paper provides guidelines for the design of high-efficiency, cost-competitive and low...... organic Rankine cycle technology presents larger performances compared to steam Rankine cycle units, whereas the implementation of air bottoming cycle modules is not attractive from an economic and environmental perspective compared to the other two technologies. Despite the relatively high cost of the...

  14. Performance analysis of air——water dual source heat pump water heater with heat recovery

    Institute of Scientific and Technical Information of China (English)

    CHEN ZeShao; TAO WenQuan; ZHU YanWen; HU Peng

    2012-01-01

    A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.

  15. Heat recovery and seed recovery development project: preliminary design report (PDR)

    Energy Technology Data Exchange (ETDEWEB)

    Arkett, A. H.; Alexander, K. C.; Bolek, A. D.; Blackman, B. K.; Kurrle, P. E.; Tram, S. V.; Warren, A. M.; Ziobrowski, A. J.

    1981-06-01

    The preliminary design and performance characteristics are described of the 20 MWt heat recovery and seed recovery (HRSR) system to be fabricated, installed, and evaluated to provide a technological basis for the design of commercial size HRSR systems for coal-fired open-cycle MHD power plants. The system description and heat and material balances, equipment description and functional requirements, controls, interfacing systems, and operation and maintenance are detailed. Appendices include: (1) recommended environmental requirements for compliance with federal and state of Tennessee regulations, (2) channel and diffuser simulator, (3) equipment arrangement drawings, and (4) channel and diffuser simulator barrel drawings. (WHK)

  16. Waste heat recovery in a coffee roasting plant

    Energy Technology Data Exchange (ETDEWEB)

    Monte, M. De; Padoano, E.; Pozzetto, D. [Via A Valerio, Trieste (Italy). Dept. of Energetics

    2003-06-01

    The paper presents the possibility of introducing, in the event of substitution of an old plant, the recovery of heat produced during the roasting process of coffee. During the analysis, thermo and fluid dynamic operating parameters of the present plant were defined also with the support of an experimental measuring campaign. Energy recovery possibilities were then evaluated, and a possible plant solution was examined taking into consideration its economic feasibility. The case study is also interesting because the methodology used for the analysis can be generally applied to production plants, which have hot air exhaust emissions. Waste heat recovery is an important topic, not only for its economic benefits, but also for its environmental outcomes and resource saving. (author)

  17. WASTE HEAT RECOVERY IN HEAT PUMP SYSTEMS: SOLUTION TO REDUCE GLOBAL WARMING

    OpenAIRE

    Y. Baradey; M. N. A. Hawlader; Ahmad Faris Ismail; Meftah Hrairi

    2015-01-01

    Energy conversion technologies, where waste heat recovery systems are included, have received significant attention in recent years due to reasons that include depletion of fossil fuel, increasing oil prices, changes in climatic conditions, and global warming. For low temperature applications, there are many sources of thermal waste heat, and several recovery systems and potential useful applications have been proposed by researchers [1-4]. In addition, many types of equipment are used to rec...

  18. Final Report, Materials for Industrial Heat Recovery Systems, Tasks 3 and 4 Materials for Heat Recovery in Recovery Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, James R.; Kish, Joseph R.; Singh, Preet M.; Sarma, Gorti B.; Yuan, Jerry; Gorog, J. Peter; Frederick, Laurie A.; Jette, Francois R.; Meisner, Roberta A.; Singbeil, Douglas L.

    2007-12-31

    The DOE-funded project on materials for industrial heat recovery systems included four research tasks: materials for aluminum melting furnace recuperator tubes, materials and operational changes to prevent cracking and corrosion of the co-extruded tubes that form primary air ports in black liquor recovery boilers, the cause of and means to prevent corrosion of carbon steel tubes in the mid-furnace area of recovery boilers, and materials and operational changes to prevent corrosion and cracking of recovery boiler superheater tubes. Results from studies on the latter two topics are given in this report while separate reports on results for the first two tasks have already been published. Accelerated, localized corrosion has been observed in the mid-furnace area of kraft recovery boilers. This corrosion of the carbon steel waterwall tubes is typically observed in the vicinity of the upper level of air ports where the stainless clad co-extruded wall tubes used in the lower portion of the boiler are welded to the carbon steel tubes that extend from this transition point or “cut line” to the top of the boiler. Corrosion patterns generally vary from one boiler to another depending on boiler design and operating parameters, but the corrosion is almost always found within a few meters of the cut line and often much closer than that. This localized corrosion results in tube wall thinning that can reach the level where the integrity of the tube is at risk. Collection and analysis of gas samples from various areas near the waterwall surface showed reducing and sulfidizing gases were present in the areas where corrosion was accelerated. However, collection of samples from the same areas at intervals over a two year period showed the gaseous environment in the mid-furnace section can cycle between oxidizing and reducing conditions. These fluctuations are thought to be due to gas flow instabilities and they result in an unstable or a less protective scale on the carbon steel

  19. Tensiomygraphic Measurement of Atrophy Related Processes During Bed Rest and Recovery

    Science.gov (United States)

    Simunic, B. ostjan; Degens, Hans; Rittweger, Jorn; Narici, Marcco; Pisot, Venceslav; Mekjavic, Igor B.; Pisot, Rado

    2013-02-01

    Tensiomyographic (TMG) parameters were recently proposed for a non-invasive estimation of MHC distribution in human vastus lateralis muscle. However, TMG potential is even higher, offers additional insight into the skeletal muscle physiology, especially in the field of atrophy and hypertrophy. The purpose of this study is in developing time dynamics of TMG-measured contraction time (Tc) and maximal response amplitude (Dm), together with muscle belly thickness, measure thoroughly during 35-day bed rest and followed in 30-day recovery (N = 10 males; age 24.3 ± 2.6 years). Measurements were performed in two postural muscles (vastus medialis and lateralis) and one non-postural muscle (biceps femoris). During bed rest period we found different dynamics of muscle thickness decrease and Dm increase. Tc was unchanged in postural muscles, but in non-postural muscle increased significantly and stayed as such even at the end of recovery. We could conclude that TMG related parameters are more sensitive in measuring muscle atrophic and hypertrophic processes than biomedical imaging technique. However, a mechanism that regulates Dm still needs to be identified.

  20. Waste Heat Recovery: A Special Case

    Directory of Open Access Journals (Sweden)

    Mohammad S

    2015-12-01

    Full Text Available Lafarge Cement Factory at Al-Fuhais (Jordan was marked of having some energy issues which required performing site visits for defining, locating and gathering any required information related to the energy issue. Considerable amounts of waste energy were detected in exhaust gases. Moving a light spot into the exhaust gases led to quantify their available heat content and then to look for an implementation for the recovered expelled energy. Among many alternatives, electricity generation was chosen by introducing an Organic Rankine Cycle (ORC as an intermediary system between the hot exhaust gases and ambient. The operating conditions for the ORC were optimized to capture the expelled energy. For the selected working fluid (refrigerant R-123, the efficiency of ORC was found to be 14.45%. The recovered energy was found monthly varying in range of [239.9, 271.6] MW.hr, this represents only 2.66 – 3% of factory's electricity consumption. Cost saving of 500,000 $ (2.82% from the annually total amount spent on electricity was attained.

  1. Evaluation of Heat Shields from RTS Wright Industries Magnesium and Uranium Beds

    CERN Document Server

    Korinko, P S

    2002-01-01

    Heat shields from a factory test of the furnaces that will be used to heat the magnesium and uranium beds for the tritium extraction facility (TEF) were examined to determine the cause of discoloration. The samples were examined using visual, optical microscopy, electron microscopy, x-ray spectroscopy, and Auger electron spectroscopy.

  2. Experiment research on grain drying process in the heat pump assisted fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Jing Yang; Li Wang; Fi Xiang; Lige Tong; Hua Su

    2004-01-01

    A heat pump assisted fluidized bed grain drying experimental system was developed. Based on this system, a serial of experiments was performed under four kinds of air cycle conditions. According to the experimental analysis, an appropriate drying medium-air cycle for the heat pump assisted fluidized bed drying equipment was decided, which is different from the commonly used heat pump assisted drying system. The experimental results concerning the drying operation performance of the new system show that the averaged coefficient of performance (COP) can reach more than 2.5. The economical evaluation was performed and the powefficiency and great application potentiality in future market.

  3. Heat recovery versus solar collection in a ventilated double window

    International Nuclear Information System (INIS)

    The ventilated double window, as a passive heating system, acts as a heat reclaiming device. Part of the heat loss from inside through the window is returned back to the room by the air flow, acting as a heat recoverer. Incident solar radiation upon the window warms its components being part of that heat removed by the air flow delivering it into the room, acting as a solar collector. The effect of these two functions were analysed in this study, through numerical simulation based on outdoor tests under real weather conditions. It was found that solar collector function plays a small role in the pre-heating of the air. First of all this is due to the system’s transparency, which allows most of the solar radiation to enter directly to the indoor space. Secondly, in a 24 h period there are only some hours of sunshine. Instead, heat recovery works all the time, the conclusion being that this passive heating device can be used on any facade orientation. - Highlights: ► A ventilated double window provides pre-warmed air for winter ventilation. ► It recovers part of the lost heat delivering it again to the inside. ► A ventilated double window acts as a vertical solar air collector. ► The heat transfer conditions make it suitable on any facade orientation.

  4. Passive ventilation systems with heat recovery and night cooling

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    University of Denmark. Through building integration in high performance offices the system is optimized to incorporate multiple functions like heating, cooling and ventilation, thus saving the expenses of separate cooling and heating systems. The simulation results are derived using the state......In building design the requirements for energy consumption for ventilation, heating and cooling and the requirements for increasingly better indoor climate are two opposing factors. This paper presents the schematic layout and simulation results of an innovative multifunc-tional ventilation concept...... with little energy consumption and with satisfying indoor climate. The concept is based on using passive measures like stack and wind driven ventilation, effective night cooling and low pressure loss heat recovery using two fluid coupled water-to-air heat exchangers developed at the Technical...

  5. Energy recovery from sewage sludge by means of fluidised bed gasification.

    Science.gov (United States)

    Gross, Bodo; Eder, Christian; Grziwa, Peter; Horst, Juri; Kimmerle, Klaus

    2008-01-01

    Because of its potential harmful impact on the environment, disposal of sewage sludge is becoming a major problem all over the world. Today the available disposal measures are at the crossroads. One alternative would be to continue its usage as fertiliser or to abandon it. Due to the discussions about soil contamination caused by sewage sludge, some countries have already prohibited its application in agriculture. In these countries, thermal treatment is now presenting the most common alternative. This report describes two suitable methods to directly convert sewage sludge into useful energy on-site at the wastewater treatment plant. Both processes consist mainly of four devices: dewatering and drying of the sewage sludge, gasification by means of fluidised bed technology (followed by a gas cleaning step) and production of useful energy via CHP units as the final step. The process described first (ETVS-Process) is using a high pressure technique for the initial dewatering and a fluidised bed technology utilising waste heat from the overall process for drying. In the second process (NTVS-Process) in addition to the waste heat, solar radiation is utilised. The subsequent measures--gasification, gas cleaning and electric and thermal power generation--are identical in both processes. The ETVS-Process and the NTVS-Process are self-sustaining in terms of energy use; actually a surplus of heat and electricity is generated in both processes. PMID:17919896

  6. Thermal energy storage for industrial waste heat recovery

    Science.gov (United States)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    The potential is examined for waste heat recovery and reuse through thermal energy storage in five specific industrial categories: (1) primary aluminum, (2) cement, (3) food processing, (4) paper and pulp, and (5) iron and steel. Preliminary results from Phase 1 feasibility studies suggest energy savings through fossil fuel displacement approaching 0.1 quad/yr in the 1985 period. Early implementation of recovery technologies with minimal development appears likely in the food processing and paper and pulp industries; development of the other three categories, though equally desirable, will probably require a greater investment in time and dollars.

  7. Water recovery using waste heat from coal fired power plants.

    Energy Technology Data Exchange (ETDEWEB)

    Webb, Stephen W.; Morrow, Charles W.; Altman, Susan Jeanne; Dwyer, Brian P.

    2011-01-01

    The potential to treat non-traditional water sources using power plant waste heat in conjunction with membrane distillation is assessed. Researchers and power plant designers continue to search for ways to use that waste heat from Rankine cycle power plants to recover water thereby reducing water net water consumption. Unfortunately, waste heat from a power plant is of poor quality. Membrane distillation (MD) systems may be a technology that can use the low temperature waste heat (<100 F) to treat water. By their nature, they operate at low temperature and usually low pressure. This study investigates the use of MD to recover water from typical power plants. It looks at recovery from three heat producing locations (boiler blow down, steam diverted from bleed streams, and the cooling water system) within a power plant, providing process sketches, heat and material balances and equipment sizing for recovery schemes using MD for each of these locations. It also provides insight into life cycle cost tradeoffs between power production and incremental capital costs.

  8. CFD Modelling of Heat Supply in Fluidized Bed Fast Pyrolysis of Biomass

    OpenAIRE

    Mellin, Pelle; Wu, Yueshi; Kantarelis, Efthymios; Yang, Weihong

    2014-01-01

    This paper investigates the heat supply to the fast pyrolysis process, by addition of oxygen in the fluidizing gas. Since the technology will be further developed, a solution for the heat supply in a large-scale reactor must be conceived, which is one option to achieve the primary target: to operate with as little extra heat as possible. Corrections for the granular bed material and the biomass particles are implemented in the simulation. User Defined Functions (UDF) is extensively used to de...

  9. Theoretical and experimental investigation of a Moving Bed Heat Exchanger for Solar Central Receiver Power Plants

    International Nuclear Information System (INIS)

    A Moving Bed Heat Exchanger for heat extraction from solar heated granular materials is investigated with respect to flow behaviour. To overcome limitations of existing empirical models, a numerical CFD model is established and parametrised with the help of experiments. Parametric studies are performed to quantify the effect of inlet velocities on the velocity field. A good agreement with an empirical model is found. Also, a comparison with PIV measurements confirms its validity, making it a solid basis for future design work.

  10. Determinations of effective heat transport coefficients for wall-cooled packed beds

    OpenAIRE

    Borkink, J.G.H.; Westerterp, K.R.

    1992-01-01

    The influence is studied of several assumptions, often made in literature, on the values for the effective radial heat conductivity, wall heat transfer coefficient and overall heat transfer coefficient, as obtained from experiments in wall-cooled packed beds without a chemical reaction. Especially the choice of the inlet boundary condition can have a large impact on the values obtained. The influence of the presence of a radial velocity profile and also the cross-correlation of the parameters...

  11. Fluidized bed spray granulation: analysis of heat and mass transfers and dynamic particle populations

    Directory of Open Access Journals (Sweden)

    S. Heinrich

    2005-06-01

    Full Text Available A model was developed taking into consideration the heat and mass transfer processes in liquid-sprayed fluidized beds. Such fluidized beds (FB are used for granulation, coating and agglomeration. Conclusions are drawn on the relevance of particle dispersion, spraying and drying to temperature and concentrations distributions. In extension, the model was coupled with a population balance model to describe the particle size distribution and the seeds formation for continuous external FBSG (fluidized bed spray granulation with non-classifying product discharge and a screening and milling unit in the seeds recycle. The effects of seeds formation on the stability of the process is discussed.

  12. Heat recovery from a cement plant with a Marnoch Heat Engine

    International Nuclear Information System (INIS)

    This paper examines the performance of a new Marnoch Heat Engine (MHE) that recovers waste heat from within a typical cement plant. Two MHE units with compressed air as the working fluid are installed to recover the waste heat. The first unit on the main stack has four pairs of shell and tube heat exchangers. The second heat recovery unit is installed on a clinker quenching system. This unit operates with three pairs of shell and tube heat exchangers. The recovered heat is converted to electricity through the MHE system and used internally within the cement plant. A predictive model and results are presented and discussed. The results show the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant. The new heat recovery system increases the efficiency of the cement plant and lowers the CO2 emissions from the clinker production process. Moreover, it reduces the amount of waste heat to the environment and lowers the temperature of the exhaust gases. - Highlights: → This paper examines the thermodynamic performance of a new Marnoch Heat Engine (MHE) that recovers waste heat to produce electricity and improve the operating efficiency of a typical cement plant. → The first unit of the MHE on the main stack has four pairs of shell and tube heat exchangers and the second heat recovery unit is installed on a clinker quenching system. → Both predicted and experimental results demonstrate the promising performance of the MHE's capabilities for efficient generation of electricity from waste heat sources in a cement plant.

  13. Packed fluidization, enhancement of heat transfer in pebble bed and thermonuclear fusion technology

    International Nuclear Information System (INIS)

    Packed fluidization is a technique in which small particles (size: 100-800 μm) are allowed to fluidize in the interstices of stationary pebbles (size: >1.0 mm). Packed fluidization enhances the rate of heat transfer in pebble bed at low operative gas velocity as well as at low pressure drop across the bed. Experiments were conducted to study heat transfer in unary packed bed and binary packed fluidized bed using lithium titanate and alumina pebbles (size: 3-10 mm) and lithium titanate and silica particles (size: 231-780 μm). It was found that due to packed fluidization the rate of heat transfer is enhanced and arms of the effective thermal conductivity this enhancement was up to 260%. Low thermal conductivity of pebble bed of solid breeder materials is one of the adverse key issues which must be addressed properly for the successful development of the thermonuclear fusion technology. Packed fluidization enhances the effective thermal conductivity of the pebble bed of solid breeder materials in the Test Blanket Module (TBM) of ITER type fusion reactor. (author)

  14. Savings flow from waste heat recovery at Syncrude

    Energy Technology Data Exchange (ETDEWEB)

    Matte, C.; Velden, J. [Syncrude Canada Ltd., Fort McMurray, AB (Canada)

    2005-10-01

    Syncrude Canada Ltd. is the world's largest producer of crude oil from oil sands. Its Athabasca oil deposit produces approximately 247,000 barrels per day of high-quality, sweet crude oil called Syncrude Sweet Blend. The recycle water system at the oil sand operations has been upgraded to optimize the waste heat recovery at the preheaters. The recycle water system provides hot process water for extracting bitumen from oil sands, and also the cooling water required by the upgrader that turns bitumen into crude oil. The upgrade has nearly doubled the amount of waste heat recovered at preheaters, resulting in energy savings of almost $2.5 million and a reduction of 24,900 tonnes in greenhouse gas emissions in the winter of 2003-2004. The preheaters are key to the bitumen extraction process. Ten massive heat exchangers recover heat from the upgrading cooling tower, to be used to heat water to extract bitumen from the oil sands. The effort to upgrade the system was initiated in 1997 with the replacement of the diluent recovery plants with more efficient twisted tube exchangers, in order to recover waste heat without compromising production. This paper described the delicate balance of making the system run as efficiently as possible. Since the optimal outlet temperature for the pre-heaters is about 20 degrees C, their use is not required in the late spring and summer when the temperature of the recycle pond is above 20 degrees C. The greatest gain in heat recovery occurred during the winter of 1998 when pumping capacity was increased by changing the pump impeller size. This measure supplied more water for the extracting process and made it possible to use the pre-heaters all winter long. Motorized valves were also installed to better clean the heat exchangers and minimize fouling of the exchanger tubes. It was concluded that the waste heat recovery can be attributed to well trained staff at the processing plant who monitor the performance of the system and make

  15. Ammonia and Carbon Dioxide Heat Pumps for Heat Recovery in Industry

    OpenAIRE

    Brix, Wiebke; Christensen, Stefan W.; Markussen, Michael M.; Reinholdt, Lars; Elmegaard, Brian

    2012-01-01

    This paper presents a generic, numerical study of high temperature heat pumps for waste heat recovery in industry using ammonia and carbon dioxide as refrigerants. A study of compressors available on the market today, gives a possible application range of the heat pumps in terms of temperatures. Calculations of cycle performances are performed using a reference cycle for both ammonia and carbon dioxide as refrigerant. For each cycle a thorough sensitivity analysis reveals that the forward and...

  16. Experimental measurement of variation of heat transfer coefficient and temperature gradients in 16'' deep fluidised beds

    International Nuclear Information System (INIS)

    The object of the experiments was to choose suitable particulate materials for a fluidised bed cooler, to test a deep fluidised bed for uniformity of heat transfer coefficient, and to explore the temperature distribution in a centrally heated annular fluidised bed. This memorandum records the techniques used and some of the practical aspects involved, together with the performance results obtained, for the assistance of other experimenters who may wish to use fluidised beds as a laboratory technique. Mathematical correlation of the results has not been attempted since some of the properties of the bed material were not known and to determine them was beyond the scope of the work programme. Rather, we have compared our results with those of other experimenters. Graphite tubes, for use in steady state thermal stress experiments, are to be heated by a graphite radiant heater situated in the bore and cooled on the outer surface. The tubes are 2 cm. bore, 8 cm. outside diameter and 48 cm. long. The outside temperature of the tubes is to be between 500 deg. C. and 1500 deg. C. It is estimated that the heat transfer rate required for fracture at the outer surface is 30 watts/cm2. This could readily be achieved by cooling with liquid metals, water or high velocity gas. However, serious problems of either materials compatibility or mechanical complexity make these undesirable. A water-cooled fluidised bed of compatible solids fluidised with nitrogen gas can overcome most of these problems and give heat transfer coefficients close to that required, vis. about 0.1 w/cm C . A coolant bed about 20'' long would be required and an annulus of about 2'' radial width round the specimen was considered to be practicable

  17. Optimal study of a solar air heating system with pebble bed energy storage

    International Nuclear Information System (INIS)

    Highlights: → Use two kinds of circulation media in the solar collector. → Air heating and pebble bed heat storage are applied with different operating modes. → Design parameters of the system are optimized by simulation program. → It is found that the system can meet 32.8% of the thermal energy demand in heating season. → Annual solar fraction aims to be 53.04%. -- Abstract: The application of solar air collectors for space heating has attracted extensive attention due to its unique advantages. In this study, a solar air heating system was modeled through TRNSYS for a 3319 m2 building area. This air heating system, which has the potential to be applied for space heating in the heating season (from November to March) and hot water supply all year around in North China, uses pebble bed and water storage tank as heat storage. Five different working modes were designed based on different working conditions: (1) heat storage mode, (2) heating by solar collector, (3) heating by storage bed, (4) heating at night and (5) heating by an auxiliary source. These modes can be operated through the on/off control of fan and auxiliary heater, and through the operation of air dampers manually. The design, optimization and modification of this system are described in this paper. The solar fraction of the system was used as the optimization parameter. Design parameters of the system were optimized by using the TRNSYS program, which include the solar collector area, installation angle of solar collector, mass flow rate through the system, volume of pebble bed, heat transfer coefficient of the insulation layer of the pebble bed and water storage tank, height and volume of the water storage tank. The TRNSYS model has been verified by data from the literature. Results showed that the designed solar system can meet 32.8% of the thermal energy demand in the heating season and 84.6% of the energy consumption in non-heating season, with a yearly average solar fraction of 53.04%.

  18. Heat Recovery in Combination with Different Heat Pump Solutions for Energy Supply

    OpenAIRE

    Solberg, Atle

    2015-01-01

    The main purpose of this Master's thesis has been to investigate the performance of different methods of heat recovery from ventilation air. Comparisons have been made with regard to delivered energy for heating of domestic hot water, space heating and ventilation heating. A single-unit dwelling was used as a basis for the simulations. The house, built in accordance with the Norwegian passive house standard, had a gross internal area of 172.6 m². Seven different combinations of a heat wheel, ...

  19. Heat Transfer Characteristics of Calcined Petroleum Coke in Waste Heat Recovery Process

    OpenAIRE

    Bin Zheng; Yongqi Liu; Lichen Zou; Ruiyang Li

    2016-01-01

    This paper reports the results of heat transfer characteristics of calcined petroleum coke in waste heat recovery process. The model of heat exchanger was set up. The model has been used to investigate the effects of porosity (0.58 to 0.79), equivalent heat conductivity coefficient (0.9 to 1.1), and equivalent specific heat (0.9 to 1.1). The calculated values of calcined petroleum coke temperature showed good agreement with the corresponding available experimental data. The temperature distri...

  20. Heat Transfer Calculations for a Fixed CST Bed Column

    International Nuclear Information System (INIS)

    In support of the crystalline silicotitanate (CST) ion exchange project of High-Level Waste (HLW) Process Engineering, a transient two-dimensional heat transfer model that includes the conduction process neglecting the convection cooling mechanism inside the CST column has been constructed and heat transfer calculations made for the present design configurations. For this situation, a no process flow condition through the column was assumed as one of the reference conditions for the simulation of a loss-of-flow accident. The modeling and calculations were performed using a computational heat transfer approach

  1. Total Energy Recovery System for Agribusiness. [Geothermally heated]. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Fogleman, S.F.; Fisher, L.A.; Black, A.R.; Singh, D.P.

    1977-05-01

    An engineering and economic study was made to determine a practical balance of selected agribusiness subsystems resulting in realistic estimated produce yields for a geothermally heated system known as the Total Energy Recovery System for Agribusiness. The subsystem cycles for an average application at an unspecified hydrothermal resources site in the western United States utilize waste and by-products from their companion cycles insofar as practicable. Based on conservative estimates of current controlled environment yields, produce wholesale market prices, production costs, and capital investment required, it appears that the family-operation-sized TERSA module presents the potential for marginal recovery of all capital investment costs. In addition to family- or small-cooperative-farming groups, TERSA has potential users in food-oriented corporations and large-cooperative-agribusiness operations. The following topics are considered in detail: greenhouse tomatoes and cucumbers; fish farming; mushroom culture; biogas generation; integration methodology; hydrothermal fluids and heat exchanger selection; and the system. 133 references. (MHR)

  2. Optimal waste heat recovery Rankine based for heavy duty applications

    OpenAIRE

    Grelet, Vincent; Reiche, Thomas; Guillaume, Ludovic; Lemort, Vincent

    2014-01-01

    Even in nowadays engines which can reach 45% of efficiency a high amount of energy is released as heat to the ambient. The increase in oil prices compels manufacturers to focus on new solutions to improve fuel efficiency of truck powertrain such as Waste Heat Recovery Systems (WHRS). Over last few years a lot of studies have proven that there are a lot of hurdles (cooling margin, expansion machines, …) for a perfect match of such a system on a vehicle. The objective of this study is to define...

  3. Cogeneration and Heat Recovery in the Industrial Process

    Directory of Open Access Journals (Sweden)

    Vujasinović, E.

    2007-11-01

    Full Text Available Related to energy requirements for non-cellulose i. e. polyester production as an energy-intensive process, potential saving options are proposed. From the process data, it is evident that unit operations need electric and thermal energy in significant amounts. At the same time, improved energy management could be realized by applying a combined heat and power system (CHP instead of the usually used process with separate heat and power production. In addition, the boiler flue gases with a sufficiently high outlet temperature could be used for combustion air preheating.Considering industrial process data, a calculation and comparison between the primary energy demand for conventional, CHP system and flue-gas heat recovery is presented. Comparison between separate heat and electricity production i.e. the conventional system with an overall efficiency of 55.6 % and CHP with efficiency of 85 %, shows an absolute efficiency increase of 29.4 %. Using an air preheater for combustion air temperature increasing saves 5.6 % of the fuel and at the same time diminishes thermal pollution because the exhaust flue-gas temperature becomes 77.3 °C instead of 204 °C. Conclusively, cogeneration and flue-gas heat recovery presentsfuel savings, which also implies economic and environmental benefits.

  4. Geothermal Energy Production With Innovative Methods Of Geothermal Heat Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Swenson, Allen [GeoTek Energy, LLC, Frisco, TX (United States); Darlow, Rick [GeoTek Energy, LLC, Frisco, TX (United States); Sanchez, Angel [GeoTek Energy, LLC, Frisco, TX (United States); Pierce, Michael [GeoTek Energy, LLC, Frisco, TX (United States); Sellers, Blake [GeoTek Energy, LLC, Frisco, TX (United States)

    2014-12-19

    The ThermalDrive™ Power System (“TDPS”) offers one of the most exciting technological advances in the geothermal power generation industry in the last 30 years. Using innovations in subsurface heat recovery methods, revolutionary advances in downhole pumping technology and a distributed approach to surface power production, GeoTek Energy, LLC’s TDPS offers an opportunity to change the geothermal power industry dynamics.

  5. Waste Heat Recovery. Technology and Opportunities in U.S. Industry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Ilona [BCS, Inc., Laurel, MD (United States); Choate, William T. [BCS, Inc., Laurel, MD (United States); Davidson, Amber [BCS, Inc., Laurel, MD (United States)

    2008-03-01

    This study was initiated in order to evaluate RD&D needs for improving waste heat recovery technologies. A bottomup approach is used to evaluate waste heat quantity, quality, recovery practices, and technology barriers in some of the largest energyconsuming units in U.S. manufacturing. The results from this investigation serve as a basis for understanding the state of waste heat recovery and providing recommendations for RD&D to advance waste heat recovery technologies.

  6. Applications of thermal energy storage to waste heat recovery in the food processing industry

    Science.gov (United States)

    Wojnar, F.; Lunberg, W. L.

    1980-01-01

    A study to assess the potential for waste heat recovery in the food industry and to evaluate prospective waste heat recovery system concepts employing thermal energy storage was conducted. The study found that the recovery of waste heat in canning facilities can be performed in significant quantities using systems involving thermal energy storage that are both practical and economical. A demonstration project is proposed to determine actual waste heat recovery costs and benefits and to encourage system implementation by the food industry.

  7. Optimization of enhanced coal-bed methane recovery using numerical simulation

    International Nuclear Information System (INIS)

    Although the enhanced coal-bed methane (ECBM) recovery process is one of the potential coal bed methane production enhancement techniques, the effectiveness of the process is greatly dependent on the seam and the injecting gas properties. This study has therefore aimed to obtain a comprehensive knowledge of all possible major ECBM process-enhancing techniques by developing a novel 3D numerical model by considering a typical coal seam using the COMET 3 reservoir simulator. Interestingly, according to the results of the model, the generally accepted concept that there is greater CBM (coal-bed methane) production enhancement from CO2 injection, compared to the traditional water removal technique, is true only for high CO2 injection pressures. Generally, the ECBM process can be accelerated by using increased CO2 injection pressures and reduced temperatures, which are mainly related to the coal seam pore space expansion and reduced CO2 adsorption capacity, respectively. The model shows the negative influences of increased coal seam depth and moisture content on ECBM process optimization due to the reduced pore space under these conditions. However, the injection pressure plays a dominant role in the process optimization. Although the addition of a small amount of N2 into the injecting CO2 can greatly enhance the methane production process, the safe N2 percentage in the injection gas should be carefully predetermined as it causes early breakthroughs in CO2 and N2 in the methane production well. An increased number of production wells may not have a significant influence on long-term CH4 production (50 years for the selected coal seam), although it significantly enhances short-term CH4 production (10 years for the selected coal seam). Interestingly, increasing the number of injection and production wells may have a negative influence on CBM production due to the coincidence of pressure contours created by each well and the mixing of injected CO2 with CH4. (paper)

  8. Optimization of enhanced coal-bed methane recovery using numerical simulation

    Science.gov (United States)

    Perera, M. S. A.; Ranjith, P. G.; Ranathunga, A. S.; Koay, A. Y. J.; Zhao, J.; Choi, S. K.

    2015-02-01

    Although the enhanced coal-bed methane (ECBM) recovery process is one of the potential coal bed methane production enhancement techniques, the effectiveness of the process is greatly dependent on the seam and the injecting gas properties. This study has therefore aimed to obtain a comprehensive knowledge of all possible major ECBM process-enhancing techniques by developing a novel 3D numerical model by considering a typical coal seam using the COMET 3 reservoir simulator. Interestingly, according to the results of the model, the generally accepted concept that there is greater CBM (coal-bed methane) production enhancement from CO2 injection, compared to the traditional water removal technique, is true only for high CO2 injection pressures. Generally, the ECBM process can be accelerated by using increased CO2 injection pressures and reduced temperatures, which are mainly related to the coal seam pore space expansion and reduced CO2 adsorption capacity, respectively. The model shows the negative influences of increased coal seam depth and moisture content on ECBM process optimization due to the reduced pore space under these conditions. However, the injection pressure plays a dominant role in the process optimization. Although the addition of a small amount of N2 into the injecting CO2 can greatly enhance the methane production process, the safe N2 percentage in the injection gas should be carefully predetermined as it causes early breakthroughs in CO2 and N2 in the methane production well. An increased number of production wells may not have a significant influence on long-term CH4 production (50 years for the selected coal seam), although it significantly enhances short-term CH4 production (10 years for the selected coal seam). Interestingly, increasing the number of injection and production wells may have a negative influence on CBM production due to the coincidence of pressure contours created by each well and the mixing of injected CO2 with CH4.

  9. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-10-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidising gas, (3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger, and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  10. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-07-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidizing gas,(3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  11. A review of dryout heat fluxes and coolability of particle beds. APRI 4, Stage 2 Report

    Energy Technology Data Exchange (ETDEWEB)

    Lindholm, Ilona [VTT Energy, Helsinki (Finland)

    2002-04-01

    Dryout heat flux experiments on particle beds have been reviewed. The observed dryout heat flux varies from some tens of kW/m{sup 2} to well over 1 MW/m 2 . The variation can be qualitatively and to some extent also quantitatively explained. The effect of particle diameter has been clearly demonstrated. For particles having diameter less than about 1 mm, the dryout heat flux on the order of 100-200 kW/m{sup 2}, and increases on square of the particle diameter. For larger than 1 mm particles the dryout heat flux increases on square root of the particle diameter. Typical values for {approx} 5 mm particles is 500 kW/m{sup 2} to 1 MW/m{sup 2} . An effect of bed thickness can be seen for small particles and medium range (50-500 mm) beds. For thick beds, > 500 mm, the dryout heat flux does not any more change as the bed height increases. The dryout heat flux increases with increasing coolant pressure. This can be explained by the increasing vapour density, which can remove more latent heat from the bed. Debris bed stratification, with small particles on top, clearly decreases the dryout heat flux. The dryout heat flux in a stratified bed can even be smaller than a heat flux of an equivalent debris bed consisting of the smaller particles alone. This is due to the capillary force, which draws liquid towards the smaller particles and causes the dryout to occur at the interface of the particle layers. A model has been developed by Lipinski to estimate dryout heat fluxes in a particle bed. The model has been derived based on solution of momentum, energy and mass conservation equations for two phases. The 1-D model can take into account variable particle sizes (stratification) along the bed and different coolant entry positions. It has been shown that the model can quite well predict the observed dryout characteristics in most experiments. The simpler 0-D model can give reasonable estimates for non-stratified beds. Results and observations of several tests on melt jet

  12. IEA Annex 26: Advanced Supermarket Refrigeration/Heat Recovery Systems

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, VAN

    2003-05-19

    With increased concern about the impact of refrigerant leakage on global warming, a number of new supermarket refrigeration system configurations requiring significantly less refrigerant charge are being considered. In order to help promote the development of advanced systems and expand the knowledge base for energy-efficient supermarket technology, the International Energy Agency (IEA) established IEA Annex 26 (Advanced Supermarket Refrigeration/Heat Recovery Systems) under the ''IEA Implementing Agreement on Heat Pumping Technologies''. Annex 26 focuses on demonstrating and documenting the energy saving and environmental benefits of advanced systems design for food refrigeration and space heating and cooling for supermarkets. Advanced in this context means systems that use less energy, require less refrigerant and produce lower refrigerant emissions. Stated another way, the goal is to identify supermarket refrigeration and HVAC technology options that reduce the total equivalent warming impact (TEWI) of supermarkets by reducing both system energy use (increasing efficiency) and reducing total refrigerant charge. The Annex has five participating countries: Canada, Denmark, Sweden, the United Kingdom, and the United States. The working program of the Annex has involved analytical and experimental investigation of several candidate system design approaches to determine their potential to reduce refrigerant usage and energy consumption. Advanced refrigeration system types investigated include the following: distributed compressor systems--small parallel compressor racks are located in close proximity to the food display cases they serve thus significantly shortening the connecting refrigerant line lengths; secondary loop systems--one or more central chillers are used to refrigerate a secondary coolant (e.g. brine, ice slurry, or CO2) that is pumped to the food display cases on the sales floor; self-contained display cases--each food display case

  13. Thermoelectric waste heat recovery from an M1 Abrams tank

    Science.gov (United States)

    Stokes, C. David; Thomas, Peter M.; Baldasaro, Nicholas G.; Mantini, Michael J.; Venkatasubramanian, Rama; Barton, Michael D.; Cardine, Christopher V.; Walker, Grayson W.

    2012-06-01

    The addition of advanced sensors, targeting systems and electronic countermeasures to military vehicles has created a strategic need for additional electric power. By incorporating a thermoelectric (TE) waste heat recovery system to convert available exhaust heat to electricity, increased electric power needs can be met without reducing the energy efficiency of the vehicle. This approach allows existing vehicles to be upgraded without requiring a complete re-design of the engine and powertrain to support the integration of advanced electronic sensors and systems that keep the performance at the state of the art level. RTI has partnered with General Dynamics Land Systems and Creare, Inc. under an Army Research Lab program to develop a thermoelectric exhaust waste heat recovery system for the M1 Abrams tank. We have designed a reduced-scale system that was retrofitted to the tank and generated 80W of electric power on the vehicle operating on a test track by capturing a portion of the exhaust heat from the Honeywell/Lycoming AGT-1500 gas turbine engine.

  14. Energy recovery from heavy ASR by co-incineration in a fluidized bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, Isabel; Caneghem, Jo van; Block, Chantal; Vandecasteele, Carlo [University of Leuven, Department of Chemical Engineering, Leuven (Belgium); Brecht, Andres van; Wauters, Guido [Indaver NV, Mechelen (Belgium)

    2012-10-15

    Automotive shredder residue (ASR) is a heterogeneous waste stream with varying particle size and elemental composition. Owing to its complexity and hazardous characteristics, landfilling of ASR is still a common practice. Nevertheless, incineration with energy recovery of certain ASR fractions (Waste-to-Energy, WtE) emerges as an interesting alternative. In a full scale experiment, a waste mix of 25 % heavy ASR, 25 % refuse derived fuel (RDF), and 50 % waste water treatment (WWT) sludge was incinerated in the SLECO fluidized bed combustor (FBC) at the Indaver site in Antwerp, Belgium. Input and output streams were sampled and analyzed to make an inventory of the most important pollutants and toxics. The inventory was further used to determine the environmental impact. Results are compared to those of two other scenarios: incineration of the usual waste feed (70 % RDF and 30 % WWT sludge) and co-incineration of 39 % ASR with 61 % WWT sludge. It can be concluded that co-incineration of heavy ASR in an existing FBC is a valid and clean technology to increase current reuse and recovery rates. In the considered FBC, 27 % of the energetic value of ASR can be recovered, while all emissions remain well below regulatory limits and only 12.6 % of the heavy ASR needs to be landfilled. The proportion of ASR in the input waste mix is however limited by the heavy metal concentration in the ASR and the generated ashes. (orig.)

  15. Recovery of energy and iron from oily sludge pyrolysis in a fluidized bed reactor.

    Science.gov (United States)

    Qin, Linbo; Han, Jun; He, Xiang; Zhan, Yiqiu; Yu, Fei

    2015-05-01

    In the steel industry, about 0.86 ton of oily sludge is produced for every 1000 tons of rolling steel. Due to the adverse impact on human health and the environment, oily sludge is designated as a hazardous waste in the Resource Conservation and Recovery Act (RCRT). In this paper, the pyrolysis treatment of oily sludge is studied in a fluidized bed reactor at a temperature range of 400-600 °C. During oily sludge pyrolysis, a maximum oil yield of 59.2% and a minimum energy loss of 19.0% are achieved at 500 °C. The energy consumption of treating 1 kg oily sludge is only 2.4-2.9 MJ. At the same time, the energy of produced oil, gas and solid residue are 20.8, 6.32, and 0.83 MJ, respectively. In particular, it is found that the solid residue contains more than 42% iron oxide, which can be used as the raw material for iron production. Thus, the simultaneous recovery of energy and iron from oil sludge by pyrolysis is feasible. PMID:25728916

  16. Experimental investigation of thermal conductivity coefficient and heat exchange between fluidized bed and inclined exchange surface

    Directory of Open Access Journals (Sweden)

    B. Stojanovic

    2009-06-01

    Full Text Available The paper presents experimental research of thermal conductivity coefficients of the siliceous sand bed fluidized by air and an experimental investigation of the particle size influence on the heat transfer coefficient between fluidized bed and inclined exchange surfaces. The measurements were performed for the specific fluidization velocity and sand particle diameters d p=0.3, 0.5, 0.9 mm. The industrial use of fluidized beds has been increasing rapidly in the past 20 years owing to their useful characteristics. One of the outstanding characteristics of a fluidized bed is that it tends to maintain a uniform temperature even with nonuniform heat release. On the basis of experimental research, the influence of the process's operational parameters on the obtained values of the bed's thermal conductivity has been analyzed. The results show direct dependence of thermal conductivity on the intensity of mixing, the degree of fluidization, and the size of particles. In the axial direction, the coefficients that have been treated have values a whole order higher than in the radial direction. Comparison of experimental research results with experimental results of other authors shows good agreement and the same tendency of thermal conductivity change. It is well known in the literature that the value of the heat transfer coefficient is the highest in the horizontal and the smallest in the vertical position of the heat exchange surface. Variation of heat transfer, depending on inclination angle is not examined in detail. The difference between the values of the relative heat transfer coefficient between vertical and horizontal heater position for all particle sizes reduces by approximately 15% with the increase of fluidization rate.

  17. Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery

    Science.gov (United States)

    Huang, Shouyuan; Xu, Xianfan

    2016-06-01

    This paper presents a methodology for design optimization of thermoelectric-based waste heat recovery systems called thermoelectric generators (TEGs). The aim is to maximize the power output from thermoelectrics which are used as add-on modules to an existing gas-phase heat exchanger, without negative impacts, e.g., maintaining a minimum heat dissipation rate from the hot side. A numerical model is proposed for TEG coupled heat transfer and electrical power output. This finite-volume-based model simulates different types of heat exchangers, i.e., counter-flow and cross-flow, for TEGs. Multiple-filled skutterudites and bismuth-telluride-based thermoelectric modules (TEMs) are applied, respectively, in higher and lower temperature regions. The response surface methodology is implemented to determine the optimized TEG size along and across the flow direction and the height of thermoelectric couple legs, and to analyze their covariance and relative sensitivity. A genetic algorithm is employed to verify the globality of the optimum. The presented method will be generally useful for optimizing heat-exchanger-based TEG performance.

  18. Hydrodynamics and Transient Heat Transfer Characteristics in Fluidized and Spouted Beds

    OpenAIRE

    Brown, Steven Lewis

    2012-01-01

    Hydrodynamics and heat transfer characteristics found in fluidization were studied in a small scale laboratory fluidized bed. Experiments were designed to capture field data on multiple slit jet gas distributor systems for the validation of computational models. Localized data was quantified through the use of several novel non-intrusive experimental measurement techniques. The analyses provide a unique study that connects full field-of-view multiphase flow dynamics with transient heat transf...

  19. Heat Transfer in a Liquid-Solid Circulating Fluidized Bed Reactor with Low Surface Tension Media

    Institute of Scientific and Technical Information of China (English)

    HR Jin; H Lim; DH Lim; Y Kang; Ki-Won Jun

    2013-01-01

    Heat transfer characteristics between the immersed heater and the bed content were studied in the riser of a liquid-solid circulating fluidized bed, whose diameter and height were 0.102 m (ID) and 2.5 m, respectively. Effects of liquid velocity, particle size, surface tension of liquid phase and solid circulation rate on the overall heat transfer coefficient were examined. The heat transfer coefficient increased with increasing particle size or solid cir-culation rate due to the higher potential of particles to contact with the heater surface and promote turbulence near the heater surface. The value of heat transfer coefficient increased gradually with increase in the surface tension of liquid phase, due to the slight increase of solid holdup. The heat transfer coefficient increased with the liquid veloc-ity even in the higher range, due to the solid circulation prevented the decrease in solid holdup, in contrast to that in the conventional liquid-solid fluidized beds. The values of heat transfer coefficient were well correlated in terms of dimensionless groups as well as operating variables.

  20. Exergetic Optimization of the Heat Recovery Steam Generators by Imposing the Total Heat Transfer Area

    OpenAIRE

    Cenuşă, Victor-Eduard; Feidt, Michel; Badea, Adrian; Benelmir, Riad

    2004-01-01

    The paper presents an original and fast method for the heat recovery steam generator (HRSG) exergetic optimization. The objective is maximizing the exergy transfer to the water / steam circuit. The proposed approach, different from the classical method that fixes the pinch point, is essentially thermodynamic but it considers also the economics by imposing the total heat transfer area of HRSG. The HRSG may have one or two steam pressures, without reheat. The input data from the gas turbine are...

  1. Performance analysis of cylindrical metal hydride beds with various heat exchange options

    Energy Technology Data Exchange (ETDEWEB)

    Satya Sekhar, B. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Lototskyy, M., E-mail: mlototskyy@uwc.ac.za [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Kolesnikov, A.; Moropeng, M.L. [Department of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, Private Bag X680, Pretoria 0001 (South Africa); Tarasov, B.P. [Laboratory of Hydrogen Storage Materials, Institute of Problems of Chemical Physics, Russian Academy of Sciences, Prospect Semenova, 1, Chernogolovka 142432 (Russian Federation); Pollet, B.G. [HySA Systems Competence Centre, South African Institute for Advanced Materials Chemistry, Faculty of Natural Sciences, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2015-10-05

    Highlights: • 3D numerical model for the comparison of H{sub 2} uptake performances in MH reactors. • 4 options of heat exchange between heat transfer fluid and MH in cylindrical reactor compared. • Straight tube internal heat exchanger. • Helical coil internal heat exchanger. • External heat exchange without and with transversal fins in the MH reactor. - Abstract: A 3D numerical heat-and-mass transfer model was used for the comparison of H{sub 2} uptake performances of powdered cylindrical MH beds comprising MmNi{sub 4.6}Al{sub 0.4} hydrogen storage material. The considered options of heat exchange between the MH and a heat transfer fluid included internal cooling using straight (I) or helically coiled (II) tubing, as well as external cooling of the MH bed without (III) and with (IV) transversal fins. The dynamic performances of these layouts were compared based on the numerical simulation. The effect of heat transfer coefficient was also analysed.

  2. Effects of material properties on the competition mechanism of heat transfer of a granular bed in rotary cylinders

    International Nuclear Information System (INIS)

    Mixing and heat transfer processes of the granular materials within rotary cylinders play a key role in industrial processes. The numerical simulation is carried out by using the discrete element method (DEM) to investigate the influences of material properties on the bed mixing and heat transfer process, including heat conductivity, heat capacity, and shear modulus. Moreover, a new Péclet number is derived to determine the dominant mechanism of the heating rate within the particle bed, which is directly related to thermal and mechanical properties. The system exhibits a faster heating rate with the increase of ratio of thermal conductivity and heat capacity, or the decrease of shear modulus when inter-particle conduction dominates the heating rate; conversely, it shows a fast-mixing bed when particle convection governs the heating rate. The simulation results show good agreement with the theoretical predictions. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  3. Separation and recovery of fine particles from waste circuit boards using an inflatable tapered diameter separation bed.

    Science.gov (United States)

    Duan, Chenlong; Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

    2014-01-01

    Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (-0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5-0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25-0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (-0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution. PMID:25379546

  4. Experiments on dryout heatflux in volumetrically heated granular particle bed with the STYX facility

    International Nuclear Information System (INIS)

    Core debris coolability in the containment is studied to verify the severe accident management strategy adapted in Olkiluoto BWRs. The molten core material discharged from the failed reactor pressure vessel falls into a several meters deep water pool in the Olkiluoto containment. It is most likely, that the melt will fragment on its way down in the subcooled water pool and form a self-heating particle debris bed on the pedestal floor. The coolability of this particle bed is the key question to be answered. For investigating of the effects of Olkiluoto specific particle bed characteristics on dryout heat flux an own simulant material test facility, STYX-1 was constructed at VTT as a combined effort between VTT Industrial Systems and VTT Processes. The particles in STYX bed follow the representative size distribution constructed for Olkiluoto case and the shape of particles is irregular. The bed depth is determined to be the same as expected in Olkiluoto plant if the whole corium inventory would spread uniformly on pedestal floor. VTT Industrial Systems designed and built a test rig capable of heating a pressurised test bed immersed in water to a heat flux up to 1 MW/m2 and run the tests. The resulting power and temperature distribution data is utilised by VTT Processes to model and assess the coolability concepts related to severe accident management in the Olkiluoto BWR. Dry-out tests have been successfully conducted at 0.1-0.7 MPa pressure for uniformly mixed beds with wide range of particles sizes and irregular particle shape. The STYX testing rig has been upgraded during the project to a point where a good estimation of the critical power resulting in a local dryout can be acquired. The dry zone formed in all tests near the bottom of the 60 cm-deep granular bed. The measured dryout heat fluxes increased with increasing pressure, obtaining a value of 232 kW/m2 at near atmospheric pressure and the value of 451 kW/m2 at 6 bar overpressure. When operating according

  5. Heat transfer in a large-scale circulating fluidized bed boiler

    Institute of Scientific and Technical Information of China (English)

    CHENG Leming; WANG Qinhui; SHI Zhenglun; LUO Zhongyang; NI Mingjiang; CEN Kefa

    2007-01-01

    Heat transfer of a furnace in a large-scale circulating fluidized bed (CFB) boiler was studied based on the analysis of available heat transfer coefficient data from typical industrial CFB boilers and measured data from a 12 MWe,a 50 MWe and a 135 MWe CFB boiler.The heat transfer of heat exchanger surfaces in a furnace,in a steam/water cooled cyclone,in an external heat exchanger and in the backpass was also reviewed.Empirical correlation of heat transfer coefficient was suggested after calculating the two key parameters,solids suspension density and furnace temperature.The correlation approach agrees well with the data from the large-scale CFB boilers.

  6. Technologies for waste heat recovery in off-shore applications

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Haglind, Fredrik; Kandepu, Rambabu;

    2013-01-01

    pressure level steam Rankine cycle employing the once-through heat recovery steam generator without bypass stack. We compare the three technologies considering the combined cycle thermal efficiency, the weight, the net present value, the profitability index and payback time. Both incomes related to CO2...... technological and economic challenges that need to be overcome. However, onshore established technologies such as the steam Rankine cycle, the air bottoming cycle and the organic Rankine cycle can be tailored to recover the exhaust heat off-shore. In the present paper, benefits and challenges of these three...... the once-trough single pressure steam cycle has a combined cycle thermal efficiency of 40.8% and net present value of 13.5 M$. The total weight of the steam Rankine cycle is estimated to be around 170 ton....

  7. Effects of material properties on the competition mechanism of heat transfer of a granular bed in rotary cylinders

    Institute of Scientific and Technical Information of China (English)

    Xie Zhi-Yin; Feng Jun-Xiao

    2013-01-01

    Mixing and heat transfer processes of the granular materials within rotary cylinders play a key role in industrial processes.The numerical simulation is carried out by using the discrete element method (DEM) to investigate the influences of material properties on the bed mixing and heat transfer process,including heat conductivity,heat capacity,and shear modulus.Moreover,a new Péclet number is derived to determine the dominant mechanism of the heating rate within the particle bed,which is directly related to thermal and mechanical properties.The system exhibits a faster heating rate with the increase of ratio of thermal conductivity and heat capacity,or the decrease of shear modulus when inter-particle conduction dominates the heating rate; conversely,it shows a fast-mixing bed when particle convection governs the heating rate.The simulation results show good agreement with the theoretical predictions.

  8. Technologies for utilization of industrial excess heat: Potentials for energy recovery and CO2 emission reduction

    International Nuclear Information System (INIS)

    Highlights: • Technologies for recovery and use of industrial excess heat were investigated. • Heat harvesting, heat storage, heat utilization, and heat conversion technologies. • Heat recovery potential for Gävleborg County in Sweden was calculated. • Effects on global CO2 emissions were calculated for future energy market scenarios. - Abstract: Industrial excess heat is a large untapped resource, for which there is potential for external use, which would create benefits for industry and society. Use of excess heat can provide a way to reduce the use of primary energy and to contribute to global CO2 mitigation. The aim of this paper is to present different measures for the recovery and utilization of industrial excess heat and to investigate how the development of the future energy market can affect which heat utilization measure would contribute the most to global CO2 emissions mitigation. Excess heat recovery is put into a context by applying some of the excess heat recovery measures to the untapped excess heat potential in Gävleborg County in Sweden. Two different cases for excess heat recovery are studied: heat delivery to a district heating system and heat-driven electricity generation. To investigate the impact of excess heat recovery on global CO2 emissions, six consistent future energy market scenarios were used. Approximately 0.8 TWh/year of industrial excess heat in Gävleborg County is not used today. The results show that with the proposed recovery measures approximately 91 GWh/year of district heating, or 25 GWh/year of electricity, could be supplied from this heat. Electricity generation would result in reduced global CO2 emissions in all of the analyzed scenarios, while heat delivery to a DH system based on combined heat and power production from biomass would result in increased global CO2 emissions when the CO2 emission charge is low

  9. Low-temperature waste-heat recovery in the food and paper industries

    Energy Technology Data Exchange (ETDEWEB)

    Foell, W.K.; Lund, D.; Mitchell, J.W.; Ray, D.; Stevenson, R.; TenWolde, A.

    1980-11-01

    The potential of low-temperature waste-heat recovery technology is examined. An examination of barriers to impede waste-heat recovery is made and research programs are identified. Extensive information and data are presented in the following chapters: Waste Heat Recovery in the Wisconsin Food Industry; Waste Heat Recovery in the Wisconsin Pulp and Paper Industry; Industries' Economic Analysis of Energy Conservation Projects; Industrial Waste Heat Recovery (selection of heat-recovery heat exchangers for industrial applications, simplified procedure for selection of heat recovery heat exchangers for industrial applications, selection of heat pumps for industrial applications); Institutional Aspects of Industrial Energy Conservation (economic motivation for energy conservation and the industrial response, intrafirm idea channels and their sources, evaluation and approval of plant improvement projects, reported barriers to adopting waste heat recovery projects and recommendations for government involvement, and the final chapter is a summary with major conclusions given. Additional information is given in two appendices on the potential waste heat recovery in a cheese plant (calculation) and conditions for optimum exchanger size and break-even fuel cost. (MCW)

  10. Hybrid heat recovery - flat plate Stirling engine system

    International Nuclear Information System (INIS)

    In this paper, the possibility of process condensate heat recovery for boiler water preheating as well as for combined heat and power production for chosen process in textile industry has been investigated. The garment industry requires low pressure process steam or hot water for which production expensive fossil fuel should be used. Fuel usage can be reduced by various energy conservation methods. During the process a great quantity of hot condensate or waste hot water is rejected in the sewage system. To reduce heat wastes and improve technological process this condensate could be returned to the boiler for feed water preheating. When 60% condensate is returned to the steam generator about 8 % natural gas is saved. The rest of the condensate should be used for driving low temperature flat plate Stirling motor the advantage of the flat plate Stirling engine is ability to work at low temperatures. This engine produces electrical energy which can put in motion an electrogenerator in the same plant. While Stirling engine can be used electrical power and economical effect could be much greater using such a hybrid system the process waste heat is not only converted into useful work but at the same time thermal pollution is greatly diminished. (Author)

  11. Nutrients recovery by struvite formation from wastewater in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.W. [Civil and Environmental Engineering, Kyungnam Univ., Masan (Korea); Kwon, H.B. [Dept. of Materials Science Engineering, Kyungnam Univ., Masan (Korea); Kim, Y.J.; Jeon, H.P. [Graduate student, Civil and Environmental Engineering, Kyungnam Univ. (Korea)

    2005-07-01

    Nutrient removal and recovery from wastewater is being challenged to avoid eutrophication problems, and the discharge standards have also been tightened by water regulations. Therefore, this study was undertaken to recover the nutrients from both synthetic wastewater and swine wastewater in a fluidized bed reactor (FBR). The operational parameters were changed to find out the optimum conditions for struvite formation. The most suitable pH was identified around pH 9. When the molar ratio of magnesium as Mg: P was 2:1 in the FBR, the removal efficiency of NH{sub 4}-N and PO{sub 4}-P was 79 and 90%, respectively. The seed material was effective to form struvite in the condition of 30g dosage. Struvite crystallization in reaction was completed in 20 minutes. The growth of struvite crystals was confirmed by the analysis of XRD, FT-IR and TG-DTA. In addition, the struvite was successfully recovered when the optimum conditions were applied to the swine wastewater. (orig.)

  12. Effect of particle size on the average heat-transfer rate from a cylinder in a liquid-penetrated granular bed

    Science.gov (United States)

    Baluev, V. V.; Rzaev, A. I.

    1992-08-01

    Experimental results on the average heat transfer from a cylinder in a liquid-penetrated granular bed are presented and the dependence of the heat transfer rate on the particle size in the bed is found.

  13. Analysis of the vertical penetration of a heated fluid layer in a solid, miscible bed

    International Nuclear Information System (INIS)

    The present study investigates the mass and heat transfer for the vertical penetration of a heated fluid layer in a solid, miscible bed using water-salt solutions (ZnBr2, NaBr) and polyethylenglycol 1500 (PEG) as simulation materials. The time depending spatial distribution of the molten material (PEG) has been measured for the first time with conductivity probes. The dependence of the downward heat flux on the density ratio rho*, i.e. the density of the fluid / the density of the molten solid, has been investigated with two different methods of heating, planar heating with a heat exchanger in a defined initial distance to the PEG-surface and electrolytical volume heating with a defined and timely constant power input. For 1 2 two layers have been observed in the fluid. This phenomenon is caused among other things by an anomality of the mixture density of the system salt solution-PEG. This process affects the downward heat flux so strongly, that it is impossible to transfer the results of such a system in this region of rho* to another system, for example to a corecatcher. The discrepancies between the measured heat fluxes and heat transfer coefficients of this study and that of other authors can be explained by the different construction of the planar heater, or by different boundary conditions in the case of volume heating. (orig.)

  14. Simulation of a heat pump system for total heat recovery from flue gas

    International Nuclear Information System (INIS)

    This paper introduces an approach of using an open-cycle absorption heat pump (OAHP) for recovering waste heat from the flue gas of a gas boiler with a system model. And equivalent energy efficiency is used to evaluate two other heat recovery systems that integrate an electric compression heat pump (EHP) or an absorption heat pump (AHP) with a boiler. The key factors influencing the systems are evaluated. The OAHP system efficiency is improved by 11% compared to the base case. And the OAHP system is more efficient than the AHP or the EHP systems, especially when the solution mass flow rate is only a little less than the cold water mass flow rate. The energy efficiency comparison is supplemented with a simplified economic analysis. The results indicate that the OAHP system is the best choice for the current prices of electricity and natural gas in Beijing. - Highlights: • An OAHP system is analyzed to improve heat recovery from natural gas flue gas. • OAHP system models are presented and analyzed. • The key factors influencing the OAHP systems are analyzed. • The OAHP system is most efficient for most cases compared with other systems. • The OAHP system is more economic than other systems

  15. Second law analysis of heat transfer surfaces in circulating fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Gungor, Afsin [Department of Mechanical Engineering, Faculty of Engineering and Architecture, Nigde University, 51100 Nigde (Turkey)

    2009-07-15

    The correct sizing of the heat transfer surfaces is important to ensure proper operation, load turndown, and optimization of circulating fluidized beds (CFBs). From this point of view, in this study, the thermodynamic second law analysis of heat transfer surfaces in CFBs is investigated theoretically in order to define the parameters that affect the system efficiency. Using a previously developed 2D CFB model which uses the particle-based approach and integrates and simultaneously predicts the hydrodynamics and combustion aspects, second law efficiency and entropy generation values are obtained at different height and volume ratios of the heat transfer surfaces for CFBs. Besides that, the influences of the water flow rates and heat exchanger tube diameters on the second law efficiency are investigated. Through this analysis, the dimensions, arrangement and type of the heat transfer surfaces which achieve maximum efficiency are obtained. (author)

  16. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant

    2015-05-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

  17. Dual-Fuel Fluidized Bed Combustor Prototype for Residential Heating: Steady-State and Dynamic Behavior

    Science.gov (United States)

    Cammarota, Antonio; Chirone, Riccardo; Miccio, Michele; Sollmene, Roberto; Urcluohr, Massimo

    Fluidized bed combustion of biogenic fuels can be recognized as an attractive option for an ecologically sustainable use of biofuels in residential applications. Nevertheless, biomass combustion in fluidized bed reactors presents some drawbacks that are mainly related to mixing/segregation of fuel particles/volatile matter during devolatilization inside the bed and in the freeboard or to bed agglomeration. A prototype of a 30-50 kWth fluidized bed boiler for residential heating has been designed to burn either a gaseous combustible or a solid biomass fuel or both fuels at the same time. The prototype has been equipped with a gas burner located in the wind-box to optimize the start-up stage of the boiler and with a fluidized bed characterized by a conical geometry ("Gulf Stream" circulation) to improve the mixing of the fuel particles during both devolatilization and char burn-out. The operation of the combustor adopting wood pellets as fuel has been investigated to evaluate their use in residential combustion applications. Steady-state thermally stable regimes of operation have been recognized analyzing both boiler temperatures and gaseous emissions. The optimization of the steady-state operation of the boiler in terms of gaseous emissions has been achieved by varying the nominal thermal power and air excess. An ad-hoc experimental campaign has been carried out to analyze the dynamic performance of the prototype as a response to changes of the demanded thermal power. On the basis of the experimental data, an interpretation of the dynamic behavior of the fluidized bed boiler has been proposed.

  18. Biogas recovery from microwave heated sludge by anaerobic digestion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Biogas generated from sewage sludge,livestock waste,and food waste by anaerobic digestion is a valuable renewable energy resource.However,conventional anaerobic digestion is not an efficient process.A long hydraulic retention time and low biogas recovery rate hinder the applications of those resources.An effective pretreatment method to destroy sludge microbial cells has been one of the major concerns regarding improvement of the biogas production.This article focuses on the effects of microwave heating on sludge anaerobic digestion.Volatile suspended solid(VSS) and chemical organic demand solubilization of heated sludge were investigated.Microwave heating was found to be a rapid and efficient process for releasing organic substrates from sludge.The increase of organic dissolution ratio was not obvious when holding time was over 5 min with microwave heating.The effect of the VSS solubilization was primarily dependent on heating temperature.The highest value of VSS dissolving ratio,36.4%,was obtained at 170°C for 30 min.The COD dissolving ratio was about 25% at 170°C.Total organic carbon of treated sludge liquor was 1.98 and 2.73 g/L at 150°C and 170°C for 5 min,respectively.A biochemical methane potential(BMP) test of excess sludge and a mixture of primary and excess sludge demonstrated an increase in biogas production.The total biogas from microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days of digestion.Biogas production was 11.1% to 25.9% higher for excess sludge than for untreated sludge.The VS removal ratios of mixture sludge and excess sludge were 12% and 11% higher,respectively,compared to the untreated sludge.

  19. WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY

    OpenAIRE

    Prateep Pattanapunt; Kanokorn Hussaro; Tika Bunnakand; Sombat Teekasap

    2013-01-01

    Many industrial heating processes generate waste energy in textile industry; especially exhaust gas from the boiler at the same time reducing global warming. Therefore, this article will present a study the way to recovery heat waste from boiler exhaust gas by mean of shell and tube heat exchanger. Exhaust gas from boiler dyeing process, which carries a large amount of heat, energy consumptions could be decrease by using of waste-heat recovery systems. In this study, using ANASYS simulation p...

  20. Enhanced Coal Bed Methane Recovery and CO2 Sequestration in the Powder River Basin

    Energy Technology Data Exchange (ETDEWEB)

    Eric P. Robertson

    2010-06-01

    Unminable coal beds are potentially large storage reservoirs for the sequestration of anthropogenic CO2 and offer the benefit of enhanced methane production, which can offset some of the costs associated with CO2 sequestration. The objective of this report is to provide a final topical report on enhanced coal bed methane recovery and CO2 sequestration to the U.S. Department of Energy in fulfillment of a Big Sky Carbon Sequestration Partnership milestone. This report summarizes work done at Idaho National Laboratory in support of Phase II of the Big Sky Carbon Sequestration Partnership. Research that elucidates the interaction of CO2 and coal is discussed with work centering on the Powder River Basin of Wyoming and Montana. Sorption-induced strain, also referred to as coal swelling/shrinkage, was investigated. A new method of obtaining sorption-induced strain was developed that greatly decreases the time necessary for data collection and increases the reliability of the strain data. As coal permeability is a strong function of sorption-induced strain, common permeability models were used to fit measured permeability data, but were found inadequate. A new permeability model was developed that can be directly applied to coal permeability data obtained under laboratory stress conditions, which are different than field stress conditions. The coal permeability model can be used to obtain critical coal parameters that can be applied in field models. An economic feasibility study of CO2 sequestration in unminable coal seams in the Powder River Basin of Wyoming was done. Economic analyses of CO2 injection options are compared. Results show that injecting flue gas to recover methane from CBM fields is marginally economical; however, this method will not significantly contribute to the need to sequester large quantities of CO2. Separating CO2 from flue gas and injecting it into the unminable coal zones of the Powder River Basin seam is currently uneconomical, but can

  1. Transient characteristics and performance analysis of a vapor compression air conditioning system with condensing heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Ming Liu; Wu, Jing Yi; Xu, Yu.Xiong; Wang, Ru Zhu [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China)

    2010-11-15

    The objective of this study is to evaluate the influence of condensing heat recovery on the dynamic behavior and performance of air conditioners. The article includes a test procedure utilized to evaluate the condensing heat recovery system, relevant experimental results, a detail analysis of the mechanisms, and improvement measure on such a system. The experimental results indicate that although the condensing heat recovery has a negative effect on the cooling capacity at the start of the heat recovery process, the average cooling coefficient of performance (COP) of the system can be improved. The study also incorporates a control scheme of the electronic expansion valve (EEV) of the condensing heat recovery system. The experimental comparison between the EEV and the thermostatic expansion valve (TEV) demonstrates that the EEV has better performance in both stability and efficiency in the condensing heat recovery system. (author)

  2. Decline, recovery, and site persistence of intertidal seagrass beds in the Northern Wadden Sea since the 1930s

    Science.gov (United States)

    Dolch, Tobias; Buschbaum, Christian; Reise, Karsten

    2013-04-01

    Seagrasses fulfil several vital ecological functions and are therefore of high importance for coastal ecosystems. They are furthermore regarded as an indicator for ecosystem health. However, as seagrasses are very sensitive towards a variety of environmental parameters, particularly to human induced eutrophication, they are declining worldwide. In contrast to this global crisis of seagrass ecosystems, intertidal seagrass beds in the Northfrisian Wadden Sea (coastal North Sea) have recovered recently and may constitute the largest intertidal seagrass area in Europe. Aerial photographs taken from the Northfrisian Wadden Sea in the periods 1935 - 1937, 1958 - 1959 and 2005 were used to map long-term variability in extent and spatial distribution of intertidal seagrass beds. Photographs were visually analyzed, and seagrass beds were recorded and quantified with a geographical information system (GIS). This set of long-term records was completed by aerial mapping data until 2011. Today, seagrass beds cover more than 15 % of the tidal flat area of the Northfrisian Wadden Sea, which is rather similar to the extent they had in the 1930s. However, the seagrass development in the last 80 years is characterized by an intermittent loss of bed area of about 34 % in the late 1950s and even 60 % in the 1970s - 1990s. This is followed by a recovery and a strong increase in seagrass bed area since the mid-1990s. It is assumed that the intermittent loss was primarily caused by direct and indirect effects of eutrophication but also by increasing hydrodynamics and associated sediment instability, which are also adverse for seagrasses. The recovery is consequently the result of the decrease of these adverse effects. Despite the variability in seagrass extent, beds show a remarkable persistence at preferred sites and over several decades. Core areas for seagrass were identified in the shelter of high sands and barrier islands where the beds are protected from the prevailing westerly

  3. Performance assessment of a packed bed microstructured reactor - heat exchanger for methanol synthesis from syngas

    OpenAIRE

    Bakhtiary-Davijany, Hamidreza

    2010-01-01

    About 25% of the world’s proven natural gas reserves are located offshore with no present economic feasibility to be produced, shipped and sold. Utilization of these resources calls for developing new technologies, which enable conversion of “remote natural gas” to transportable fuels and chemicals at lower production capacities. On this context, investigation of compact methanol synthesis from synthesis gas over Cu based catalysts in a multi-slit Integrated Micro Packed Bed Reactor-Heat Exch...

  4. Simultaneous power generation and heat recovery using a heat pipe assisted thermoelectric generator system

    International Nuclear Information System (INIS)

    Highlights: • A new passive power cogeneration system using industrial waste heat was introduced. • Heat pipes and thermoelectrics were used for recovering waste heat and electricity. • Theoretical model predicted the 2 kW test rig could recover 1.345 kW thermal power. • 10.39 W electrical power was produced equivalent to 0.77% conversion efficiency. - Abstract: This research explores a new method of recovering waste heat and electricity using a combination of heat pipes and thermoelectric generators (HP-TEG). The HP-TEG system consists of Bismuth Telluride (Bi2Te3) based thermoelectric generators (TEGs), which are sandwiched between two finned heat pipes to achieve a temperature gradient across the TEG for thermoelectricity generation. A theoretical model was developed to predict the waste heat recovery and electricity conversion performances of the HP-TEG system under different parametric conditions. The modelling results show that the HP-TEG system has the capability of recovering 1.345 kW of waste heat and generating 10.39 W of electrical power using 8 installed TEGs. An experimental test bench for the HP-TEG system is under development and will be discussed in this paper

  5. Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed

    Directory of Open Access Journals (Sweden)

    Chenlong Duan

    2014-01-01

    Full Text Available Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed’s fluid flow field. For 0.5–0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25–0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (−0.125 mm, metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution.

  6. Testing heated flint palaeodose protocols using dose recovery procedures

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating of materials from archaeological contexts has been shown to be an accurate method when comparisons are made with other chronometric dating methods; however, little has been published on the verification of the measurement protocols used to determine the equivalent dose (palaeodose). Instead of testing TL dating protocols for heated flint using archaeological material with unknown thermal and radiation history, dose recovery tests for three samples of different geological origin are presented. These samples exhibit TL emission in the UV, blue and orange-red wavelengths. In addition to the two multiple aliquot protocols (standard additive-regeneration and normalization) generally used to determine the palaeodose, the single-aliquot-regenerative-dose (SAR) TL and OSL procedure, a 'short' SAR-TL and isothermal luminescence (IT) decay procedures are applied using detection windows limited to these emissions. Accurate dose recovery is obtained for the standard and normalization protocols in the commonly employed detection window (UV-blue), the 'short' SAR in the orange-red window and some IT measurements. While the standard techniques give the most accurate and precise results, detection of the TL and IT orange-red emission in connection with a 'short' SAR protocol also gave accurate and precise results. Such procedures are especially suitable for samples too small for standard multiple aliquot techniques, which require large samples

  7. A new open absorption heat pump for latent heat recovery from moist gas

    International Nuclear Information System (INIS)

    Highlights: • A new open absorption heat pump system was proposed. • The new system aims at recovering latent heat from low-temperature moist gas. • The new system can utilize a lower temperature range of heat source. • COPh and heat recovery efficiency is high with the production of high-temperature steam. • Increasing generation temperature and humidity of gas is beneficial for the new system. - Abstract: Conventional drying processes discharge high humidity gas to the atmosphere. The exhaust gas contains large amount of energy. The direct discharging would result in relatively large energy waste. In order to improve the thermal efficiency of drying process, in this paper, a new open absorption heat pump system was proposed, which aims at recovering the latent heat from exhausted moist gas and producing steam for reutilization. The working principle was discussed in detail and thermodynamic models were established to analyze the performance of the new system. The new system can work under both single-stage and double-stage modes. Simulation results showed that the new system could utilize a heat source with lower generation temperature compared with that utilized by a traditional open absorption system. The temperature range of heat source for the double-stage mode is 130–160 °C, and that for the single-stage mode is 160–175 °C. The new system also eliminates the limitation of traditional close absorption system, whose evaporation temperature has to be lower than the dew point temperature of discharged moist gas to recover the latent heat of water steam. Simulation results also indicated an improved COPh of the new system compared with that of double-stage close absorption heat pump system. The COPh of the new system varied from 1.52 to 1.97 and the efficiency of heat recovery varied from 15.1% to 54.8% when the temperature of heat source varied from 135 °C to 175 °C and saturated steam of 100 °C was produced

  8. Simulation of the pebble bed modular reactor natural air convection passive heat removal system

    International Nuclear Information System (INIS)

    Cooling of the Pebble Bed Nuclear Reactor under evaluation in South Africa is primarily effected by the flow of helium through the cavity which contains the nuclear fuel. However, apart from this, a certain amount of heat flows from the reactor cavity, through the graphite barrel and reactor vessel to the containment building and ultimately to the environment During normal operation this passive heat loss represents approximately 1MW for a 100MW reactor and constitutes an undesirable loss of power. In the event of a shutdown or loss of main coolant, however, this passive heat removal is relied upon to remove the decay heat from the core. A study was initiated to simulate the process of this heat removal to provide an indication of the maximum vessel temperature and power transfers after shutdown. However, there is a lack of precise data indicating values for thermal conductivity, heat transfer coefficients, heat capacities or even densities. This paper describes the assumptions made and the manner in which these data were estimated so as to provide what is hoped to be a reasonably accurate estimate of the behaviour of the passive heat removal process. (author)

  9. Control optimizations for heat recovery from CO2 refrigeration systems in supermarket

    International Nuclear Information System (INIS)

    Highlights: • Application of supermarket energy control system model. • Heat recovery from CO2 refrigeration system in supermarket space conditioning. • Effect of pressure controls of CO2 refrigeration system on heat recovery potentials. • Control optimization of CO2 refrigeration system for heat recovery in supermarket. - Abstract: A modern supermarket energy control system has a concurrent need for electricity, food refrigeration and space heating or cooling. Approximately 10% of this energy is for conventional gas-powered heating. In recent years, the use of CO2 as a refrigerant in supermarket systems has received considerable attention due to its negligible contribution to direct greenhouse gas emissions and excellent thermophysical and heat transfer properties. CO2 refrigeration systems also offer more compact component designs over a conventional HFC system and heat recovery potential from compressor discharge. In this paper, the heat recovery potential of an all-CO2 cascade refrigeration system in a supermarket has been investigated using the supermarket simulation model “SuperSim” developed by the authors. It has been shown that at UK weather conditions, the heat recovery potential of CO2 refrigeration systems can be increased by increasing the condenser/gas cooler pressure to the point where all the heat requirements are satisfied. However, the optimum level of heat recovery will vary during the year and the control system should be able to continuously optimize this level based on the relative cost of energy, i.e., gas and electricity

  10. Ventilation effectiveness : health benefits of heat recovery ventilators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-08-15

    Studies have shown that the installation of a heat recovery ventilator (HRV) in homes in northern Canada could improve indoor air quality and the respiratory health of inhabitants. Low ventilation rates are common in many homes in the North because the climate is severe, homes are smaller and lack basements, and occupancies are higher, leading to unhealthy indoor air quality. Northern communities also have a high rate of respiratory infections. HRVs recover much of the energy used to ventilate, which is desirable in cold regions with high heating costs. For the study, the test sample was divided into two types of houses, notably houses with active HRVs and those with control HRVs that were installed and operated but that did not function. The study results showed that HRVs provided increased ventilation. Complaints by residents about HRV noise, discomfort, or low humidity were common but equally spread between those with active and placebo HRVs. The study showed that the system design needs to be improved to better suit the needs of Inuit families. The nature of northern housing presents installation and maintenance challenges. It is hard to retrofit HRV ducting inside small, existing houses, and building supplies arrive infrequently, so detailed planning and careful take-offs of all supplies and materials must be done well in advance of construction. In addition, contractors are hard to locate and have variable expertise, and there is little technical follow-up. Robust technical support by local contractors and housing authorities is therefore important. 2 refs.

  11. Transcriptomic analysis of grape (Vitis vinifera L. leaves during and after recovery from heat stress

    Directory of Open Access Journals (Sweden)

    Liu Guo-Tian

    2012-09-01

    Full Text Available Abstract Background Grapes are a major fruit crop around the world. Heat stress can significantly reduce grape yield and quality. Changes at the molecular level in response to heat stress and subsequent recovery are poorly understood. To elucidate the effect of heat stress and subsequent recovery on expression of genes by grape leaves representing the classic heat stress response and thermotolerance mechanisms, transcript abundance of grape (Vitis vinifera L. leaves was quantified using the Affymetrix Grape Genome oligonucleotide microarray (15,700 transcripts, followed by quantitative Real-Time PCR validation for some transcript profiles. Results We found that about 8% of the total probe sets were responsive to heat stress and/or to subsequent recovery in grape leaves. The heat stress and recovery responses were characterized by different transcriptional changes. The number of heat stress-regulated genes was almost twice the number of recovery-regulated genes. The responsive genes identified in this study belong to a large number of important traits and biological pathways, including cell rescue (i.e., antioxidant enzymes, protein fate (i.e., HSPs, primary and secondary metabolism, transcription factors, signal transduction, and development. We have identified some common genes and heat shock factors (HSFs that were modulated differentially by heat stress and recovery. Most HSP genes were upregulated by heat stress but were downregulated by the recovery. On the other hand, some specific HSP genes or HSFs were uniquely responsive to heat stress or recovery. Conclusion The effect of heat stress and recovery on grape appears to be associated with multiple processes and mechanisms including stress-related genes, transcription factors, and metabolism. Heat stress and recovery elicited common up- or downregulated genes as well as unique sets of responsive genes. Moreover, some genes were regulated in opposite directions by heat stress and recovery

  12. Theoretical and experimental investigation on the transient coupled heat and mass transfer in a radial flow desiccant packed bed

    International Nuclear Information System (INIS)

    Highlights: ► We present theoretical and experimental investigation of desiccant bed. ► Transient coupled heat and mass transfer in a radial flow desiccant packed bed has been reported. ► A real-time model is used. ► The prediction of air exit conditions from the bed is carried out. - Abstract: Theoretical and experimental investigation on the transient coupled heat and mass transfer in a radial flow desiccant packed bed has been reported in the present work. An experimental test rig has been designed and constructed to carry out the required experimental measurements. System parameters and flowing air conditions (bed weight, air velocity, air conditions – dry and wet bulb temperatures- at exit of test rig components) are measured and analyzed. A hollow cylindrical packed bed has been used as a desiccant dehumidifier. This configuration decreases the required power to blow air through the bed. In the theoretical study, prediction of air exit conditions from the bed is carried out based on the model of Barlow for the analysis of adsorption and regeneration processes in the desiccant bed. This model uses simple effectiveness equations for steady-state heat and mass exchangers within a finite difference procedure. Air at different conditions of temperature and humidity enters the regenerated bed and the exit temperature and humidity are plotted with time. Acceptable agreement is found between the theoretical and experimental results. The most effective parameters on the system performance are the initial water content of the bed and its initial temperature. Bed cooling during adsorption improves the system performance.

  13. Numerical investigation of coupled heat and mass transfer during desorption of hydrogen in metal hydride beds

    Energy Technology Data Exchange (ETDEWEB)

    Muthukumar, P.; Satheesh, A.; Madhavakrishna, U.; Dewan, Anupam [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam (India)

    2009-01-15

    This paper presents a numerical investigation of two-dimensional coupled heat and mass transfer processes in MmNi{sub 4.6}Fe{sub 0.4} and MmNi{sub 4.6}Al{sub 0.4} based metal hydride beds of cylindrical configuration during desorption of hydrogen using a commercial software FLUENT 6.1.22. Temperature and concentration profiles at different radial locations, variation of average bed temperature and amount of hydrogen desorbed are presented at different hot fluid temperatures and bed thicknesses ranging from 30 to 50 C and 5 to 15 mm, respectively. The numerical results show that the dehydriding process for both the alloys depends on the temperature distribution in the metal hydride bed. At a given hot fluid temperature of 50 C, MmNi{sub 4.6}Fe{sub 0.4} and MmNi{sub 4.6}Al{sub 0.4} desorb the maximum hydrogen of about 1.11 and 1.28 wt%, respectively at the supply conditions of 30 bar and 25 C. The present computational results are also compared with the experimental data reported in the literature and a good agreement was found between the two. (author)

  14. NONUNIFORMITIES OF TWO-PHASE COOLANT DISTRIBUTION IN A HEAT GENERATING PARTICLES BED

    Directory of Open Access Journals (Sweden)

    V. V. Sorokin

    2015-02-01

    Full Text Available Sufficient atomic power generation safety increase may be done with microfuel adapting to reactor plants with water coolant. Microfuel particle is a millimeter size grain containing fission material core in a protecting coverage. The coverage protects fuel contact with coolant and provides isolation of fission products inside. Well thermophysical properties of microfuel bed in a direct contact with water coolant excludes fuel overheating when accidents. Microfuel use was suggested for a VVER, а direct flow reactor for superheat steam generation, a reactor with neutron spectra adjustment by the steam partial content varying in the coolant.Nonuniformities of two-phase coolant distribution in a heat generating particles bed are predicted by calculations in this text. The one is due to multiple-valuedness of pressure drop across the bed on the steam quality dependency. The nonuniformity decreases with flow rate and particle size growths absolute pressure diminishing while porosity effect is weak. The worse case is for pressure quality of order of one. Some pure steam filled pores appears parallel to steam water mixture filled pores, latter steam quality is less than the mean of the bed. Considering this regime for the direct flow reactor for superheat steam generation we predict some water drops at the exit flow. The two-phase coolant filtration with subcooled water feed is unstable to strong disturbance effects are found. Uniformity of two-phase coolant distribution is worse than for one-phase in the same radial type reactor.

  15. Transcriptomic analysis of grape (Vitis vinifera L.) leaves during and after recovery from heat stress

    OpenAIRE

    Liu Guo-Tian; Wang Jun-Fang; Cramer Grant; Dai Zhan-Wu; Duan Wei; Xu Hong-Guo; Wu Ben-Hong; Fan Pei-Ge; Wang Li-Jun; Li Shao-Hua

    2012-01-01

    Abstract Background Grapes are a major fruit crop around the world. Heat stress can significantly reduce grape yield and quality. Changes at the molecular level in response to heat stress and subsequent recovery are poorly understood. To elucidate the effect of heat stress and subsequent recovery on expression of genes by grape leaves representing the classic heat stress response and thermotolerance mechanisms, transcript abundance of grape (Vitis vinifera L.) leaves was quantified using the ...

  16. Experimental Evaluation of a Total Heat Recovery Unit with Polymer Membrane Foils

    DEFF Research Database (Denmark)

    Fang, Lei; Yuan, Shu; Nie, Jinzhe

    2014-01-01

    condition indoors. The airflows taken from the two chambers were connected into the total heat recovery unit and exchange heat in a polymer membrane foil heat exchanger installed inside the unit. The temperature and humidity of the air upstream and downstream of the heat exchanger were measured. Based on...... climate. The test was also conducted in isothermal conditions to observe the moisture transfer performance of the polymer membrane heat exchanger. The results of the experiment shows that total heat recovery equipment tested can recover up to 60 % of the total heat from the ventilation air. Around 87 % of...

  17. Optimal operation of integrated processes. Studies on heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Glemmestad, Bjoern

    1997-12-31

    Separators, reactors and a heat exchanger network (HEN) for heat recovery are important parts of an integrated plant. This thesis deals with the operation of HENs, in particular, optimal operation. The purpose of heat integration is to save energy, but the HEN also introduces new interactions and feedback into the overall plant. A prerequisite for optimisation is that there are extra degrees of freedom left after regulatory control is implemented. It is shown that extra degrees of freedom may not always be utilized for energy optimisation, and a quantitative expression for the degrees of freedom that can be so utilized are presented. A simplified expression that is often valid is also deduced. The thesis presents some improvements and generalisations of a structure based method that has been proposed earlier. Structural information is used to divide possible manipulations into three categories depending on how each manipulation affects the utility consumption. By means of these categories and two heuristic rules for operability, the possible manipulations are ordered in a priority table. This table is used to determine which manipulation should be preferred and which manipulation should be selected if an active manipulation is saturated. It is shown that the method may correspond to split-range control. A method that uses parametric information in addition to structural information is proposed. In this method, the optimal control structure is found through solving an integer programming problem. The thesis also proposes a method that combines the use of steady state optimisation and optimal selection of measurements. 86 refs., 46 figs., 8 tabs.

  18. Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs.

    Science.gov (United States)

    Rukke, Bjørn Arne; Aak, Anders; Edgar, Kristin Skarsfjord

    2015-01-01

    Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring's feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions. PMID:25996999

  19. Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs.

    Directory of Open Access Journals (Sweden)

    Bjørn Arne Rukke

    Full Text Available Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring's feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions.

  20. Current and future prospects for heat recovery from waste in European district heating systems: A literature and data review

    DEFF Research Database (Denmark)

    Persson, Urban; Münster, Marie

    2016-01-01

    Municipal solid waste has seen increasing annual volumes for many decades in contemporary Europe and constitutes, if not properly managed, an environmental problem due to local pollution and greenhouse gas emissions. From an energy perspective, waste is also an alternative fuel for power and heat...... heat distribution infrastructures, without which no large-scale recovery and utilisation of excess heat is possible. In this paper, which aims to estimate municipal solid waste volumes available for heat recovery in European district heating systems in 2030, a literature and data review is performed to...... generation; energy recovery from waste represents an effective measure to reduce landfilling and avoid disposal emissions while simultaneously reducing the equivalent demand for primary energy supply. A key factor for obtaining the full synergetic benefits of this energy recovery is the presence of local...

  1. Surface-particle-emulsion heat transfer model between fluidized bed and horizontal immersed tube

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A mathematical model, surface-particle-emulsion heat transfer model, is presented by considering voidage variance in emulsion in the vicinity of an immersed surface. Heat transfer near the surface is treated by dispersed particles touching the surface and through the emulsion when the distance from the surface is greater than the diameter of a particle. A film with an adjustable thickness which separates particles from the surface is not introduced in this model. The coverage ratio of particles on the surface is calculated by a stochastic model of particle packing density on a surface. By comparison of theoretical solutions with experimental data from some references, the mathematical model shows better qualitative and quantitative prediction for local heat transfer coefficients around a horizontal immersed tube in a fluidized bed.

  2. Development of Moving Bed Technology for Heat Treatment and Grinding of Dismantled Concrete

    International Nuclear Information System (INIS)

    The factors such as gas or fluid velocity, length, width and depth of each stage, number of Zig-Zag stage, angle of each stage, position of feed stage, size and amount of feed material, amount of treated concrete waste, method of fluid distribution, surface area of heat transfer, position of heater, method of heating, temperature difference between the heater and the material, amount of heat have been found to be important factors in the system. The capability of the system has been analyzed and evaluated by means of total efficiency and grade separation efficiency the experiments by using the simulated Zig-Zag type moving bed flow process with bench scale(3.2m high, Ifi-stage) have shown that the total efficiency has been in the range of 92% - 95% and the grade efficiency of 93% - 95%, respectively, elucidating that the system is quite good

  3. Model predictive control of a waste heat recovery system for automotive diesel engines

    NARCIS (Netherlands)

    Feru, E.; Willems, F.; De Jager, B.; Steinbuch, M.

    2014-01-01

    In this paper, a switching Model Predictive Control strategy is designed for an automotive Waste Heat Recovery system with two parallel evaporators. The objective is to maximize Waste Heat Recovery system output power, while satisfying safe operation under highly dynamic disturbances from the engine

  4. CFD Simulation and Experimental Analyses of a Copper Wire Woven Heat Exchanger Design to Improve Heat Transfer and Reduce the Size of Adsorption Beds

    Directory of Open Access Journals (Sweden)

    John White

    2016-02-01

    Full Text Available The chief objective of this study is the proposal design and CFD simulation of a new compacted copper wire woven fin heat exchanger and silica gel adsorbent bed used as part of an adsorption refrigeration system. This type of heat exchanger design has a large surface area because of the wire woven fin design. It is estimated that this will help improve the coefficient of performance (COP of the adsorption phase and increase the heat transfer in this system arrangement. To study the heat transfer between the fins and porous adsorbent reactor bed, two experiments were carried out and matched to computational fluid dynamics (CFD results.

  5. Study on a heat recovery system for the thermal power plant utilizing air cooling island

    International Nuclear Information System (INIS)

    A new heat recovery system for CHP (combined heat and power) systems named HRU (heat recovery unit) is presented, which could recover the low grade heat of exhausted steam from the turbine at the thermal power plant directly. Heat recovery of exhausted steam is often accomplished by recovering the heat of cooling water in current systems. Therefore, two processes of heat transfer is needed at least. However, exhausted steam could be condensed in the evaporator of HRU directly, which reduce one process of heat transfer. A special evaporator is designed condense the exhausted steam directly. Simulated results are compared to experiments, which could include the calculation of heat transfer coefficients of different parts of HRU. It is found that about 25Mw of exhausted steam is recovered by this system. HRU could be promising for conventional CHP systems, which could increase the total energy efficiency obviously and enlarge the heating capacity of a built CHP system. - Highlights: • A new heat recovery system for thermal power plant is presented. • A mathematical model including heat transfer coefficients calculation is given. • This heat recovery system is experimented at a thermal power plant. • Performances of this system under different working conditions are simulated

  6. Experimental study on full-scale ZrCo and depleted uranium beds applied for fast recovery and delivery of hydrogen isotopes

    International Nuclear Information System (INIS)

    Highlights: • Thin double-layered annulus beds with ZrCo and depleted uranium were fabricated. • Depleted uranium bed delivered 16.41 mol H2 at rate of 20 Pa m3/s within 30 min. • The delivery property of depleted uranium bed was very stable during the 10 cycles. - Abstract: Metal hydride bed is an important component for the deuterium–tritium fusion energy under development in International Thermonuclear Experimental Reactor (ITER), in which the hydrogen recovery and delivery properties are influenced by the bed configuration, operation conditions and the hydrogen storage materials contained in the bed. In this work, a thin double-layered annulus bed configuration was adopted and full-scale beds loaded with ZrCo and depleted uranium (DU) for fast recovery and delivery of hydrogen isotopes were fabricated. The properties of hydrogen recovery/delivery together with the inner structure variation in the fabricated beds were systematically studied. The effects of operation conditions on the performances of the bed were also investigated. It was found that both of the fabricated ZrCo and DU beds were able to achieve the hydrogen storage target of 17.5 mol with fast recovery rate. In addition, experimental results showed that operation of employing extra buffer vessel and scroll pump could not only promote the hydrogen delivery process but also reduce the possibility about disproportionation of ZrCo. Compared with ZrCo bed, DU bed exhibited superior hydrogen delivery performances in terms of fast delivery rate and high hydrogen delivery amount, which could deliver over 16.4 mol H2 (93.7% of recovery amount) within 30 min at the average delivery rate of 20 Pa m3/s. Good reversibility as high as 10 cycles without obvious degradation tendency in both of hydrogen delivery amount and delivery rate for DU bed was also achieved in our study. It was suggested that the fabricated thin double-layered annulus DU bed was a good candidate to rapidly deliver and recover

  7. Experimental Study of the Gas Engine Driven Heat Pump with Engine Heat Recovery

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2015-01-01

    Full Text Available Gas engine driven heat pumps (GEHPs represent one of practical solutions to effectively utilize fossil fuel energy and reduce environmental pollution. In this paper, the performance characteristics of the GEHP were investigated experimentally with engine heat recovery. A GEHP test facility was set up for this purpose. The effects of several important factors including engine speed, ambient temperature, condenser water flow rate, and condenser water inlet temperature on the system performance were studied over a wide range of operating conditions. The results showed that the engine waste heat accounted for about 40–50% of the total heat capacity over the studied operating conditions. It also showed that engine speed and ambient temperature had significant effects on the GEHP performance. The coefficient of performance (COP and the primary energy ratio (PER decreased by 14% and 12%, respectively, as engine speed increased from 1400 rpm to 2000 rpm. On the other hand, the COP and PER of the system increased by 22% and 16%, respectively, with the ambient temperature increasing from 3 to 12°C. Furthermore, it was demonstrated that the condenser water flow rate and condenser water inlet temperature had little influence on the COP of the heat pump and the PER of the GEHP system.

  8. A waste heat recovery steam power generation system for ACE Power Embilipitiya (Pvt) Ltd, Sri Lanka

    OpenAIRE

    Weerasiri, Udayani Priyadarshana

    2014-01-01

    In this study, the heat recovery from exhaust gas at the ACE Power Embilipitiya (Pvt) Ltd (APE) in Sri Lanka was conceptually proposed and evaluated. APE has an installed capacity of 100 MW comprising 14 units of 7.5MW medium speed diesel engines fired with heavy fuel oil. There is only a minimum recovery of waste heat in the plant at the moment, only for fuel preheating, whereas waste heat recovery (WHR) boilers of 750kWth are equipped on eight engines. The larger portion of the waste heat i...

  9. Waste heat and water recovery opportunities in California tomato paste processing

    International Nuclear Information System (INIS)

    Water and energy efficiency are important for the vitality of the food processing industry as demand for these limited resources continues to increase. Tomato processing, which is dominated by paste production, is a major industry in California – where the majority of tomatoes are processed in the United States. Paste processing generates large amounts of condensate as moisture is removed from the fruit. Recovery of the waste heat in this condensate and reuse of the water may provide avenues to decrease net energy and water use at processing facilities. However, new processing methods are needed to create demand for the condensate waste heat. In this study, the potential to recover condensate waste heat and apply it to the tomato enzyme thermal inactivation processing step (the hot break) is assessed as a novel application. A modeling framework is established to predict heat transfer to tomatoes during the hot break. Heat recovery and reuse of the condensate water are related to energy and monetary savings gained through decreased use of steam, groundwater pumping, cooling towers, and wastewater processing. This analysis is informed by water and energy usage data from relevant unit operations at a commercial paste production facility. The case study indicates potential facility seasonal energy and monetary savings of 7.3 GWh and $166,000, respectively, with most savings gained through reduced natural gas use. The sensitivity of heat recovery to various process variables associated with heat exchanger design and processing conditions is presented to identify factors that affect waste heat recovery. - Highlights: • The potential to recovery waste heat in tomato paste processing is examined. • Heat transfer from evaporator condensate to tomatoes in the hot break is modeled. • Processing facility data is used in model to predict heat recovery energy savings. • The primary benefit of heat recovery is reduced use of natural gas in boilers. • Reusing

  10. Study on neutron diffusion and time dependence heat ina fluidized bed nuclear reactor

    International Nuclear Information System (INIS)

    The purpose of this work is to model the neutron diffusion and heat transfer for a Fluidized Bed Nuclear Reactor and its solution by Laplace Transform Technique with numerical inversion using Fourier Series. Also Gaussian quadrature and residues techniques were applied for numerical inversion. The neutron transport, diffusion, and point Kinetic equation for this nuclear reactor concept are developed. A matricial and Taylor Series methods are proposed for the solution of the point Kinetic equation which is a time scale problem of Stiff type

  11. Radiographic examination of pressured parts for heat recovery steam generator

    International Nuclear Information System (INIS)

    A larger Nuclear Power Generation and Non Nuclear Power Generation are shipped to the job sites in various stages of fabrication and subassembly. Welding and welding related processes are central to Power Generation component fabrication and assembly in the site. This papers presents some results of the investigation that was carried out to examine the welding results of the site construction of Heat Recovery Steam Generator Piping of Tanjung Priok Gas Fired Power Plant Extension Project (740 MW) using the Radiography Test Method based on the ASME Standard. From this investigation it could be concluded that there was no crack founded in the selected specimens of the piping. The rejectable Incomplete Penetration was found in the Hot Reheat Steam Piping HRSG1. Some Porosities and Slag Inclusion are rejected because their size and length are longer than acceptable value limits, therefore should be repaired. However some of the results are accepted and no need to be repaired. The rejected Worm Holes is found on IP Super Heater Inlet Piping of HRSG1 whereas the undercut occurred on HP Steam Drum of HRSG. (author)

  12. Exergetic Optimization of the Heat Recovery Steam Generators by Imposing the Total Heat Transfer Area

    Directory of Open Access Journals (Sweden)

    Michel Feidt

    2004-09-01

    Full Text Available The paper presents an original and fast method for the heat recovery steam generator (HRSG exergetic optimization. The objective is maximizing the exergy transfer to the water / steam circuit. The proposed approach, different from the classical method that fixes the pinch point, is essentially thermodynamic but it considers also the economics by imposing the total heat transfer area of HRSG. The HRSG may have one or two steam pressures, without reheat. The input data from the gas turbine are: the mass flow rate, the temperature and the molar composition of flue gases. The results are the optimum pressures of the superheated steam. The numerical computations were realized in Delphi programming utility. The obtained results are in agreement with the recent literature.

  13. Modeling phosphorus removal and recovery from anaerobic digester supernatant through struvite crystallization in a fluidized bed reactor.

    Science.gov (United States)

    Rahaman, Md Saifur; Mavinic, Donald S; Meikleham, Alexandra; Ellis, Naoko

    2014-03-15

    The cost associated with the disposal of phosphate-rich sludge, the stringent regulations to limit phosphate discharge into aquatic environments, and resource shortages resulting from limited phosphorus rock reserves, have diverted attention to phosphorus recovery in the form of struvite (MAP: MgNH4PO4·6H2O) crystals, which can essentially be used as a slow release fertilizer. Fluidized-bed crystallization is one of the most efficient unit processes used in struvite crystallization from wastewater. In this study, a comprehensive mathematical model, incorporating solution thermodynamics, struvite precipitation kinetics and reactor hydrodynamics, was developed to illustrate phosphorus depletion through struvite crystal growth in a continuous, fluidized-bed crystallizer. A thermodynamic equilibrium model for struvite precipitation was linked to the fluidized-bed reactor model. While the equilibrium model provided information on supersaturation generation, the reactor model captured the dynamic behavior of the crystal growth processes, as well as the effect of the reactor hydrodynamics on the overall process performance. The model was then used for performance evaluation of the reactor, in terms of removal efficiencies of struvite constituent species (Mg, NH4 and PO4), and the average product crystal sizes. The model also determined the variation of species concentration of struvite within the crystal bed height. The species concentrations at two extreme ends (inlet and outlet) were used to evaluate the reactor performance. The model predictions provided a reasonably good fit with the experimental results for PO4-P, NH4-N and Mg removals. Predicated average crystal sizes also matched fairly well with the experimental observations. Therefore, this model can be used as a tool for performance evaluation and process optimization of struvite crystallization in a fluidized-bed reactor. PMID:24384559

  14. Frontal Regime of Heat and Mass Transfer in a Geothermal Bed

    Science.gov (United States)

    Alkhasov, A. B.; Ramazanov, M. M.; Alkhasova, D. A.

    2015-11-01

    Based on an earlier proposed mathematical model, the conditions for the existence of a frontal regime of steam extraction from a high-temperature bed have been derived. It is shown that unlike the familiar one-dimensional case, in the radial-symmetrical model considered the radius of the region occupied by steam tends to a limiting value, that is, the front of boiling that separates the regions of water and steam practically comes to a stop after a time. A formula has been derived pointing clearly to the dependence of the indicated limiting value of the front radius on the water and steam parameters as well as on the characteristics of the geothermal bed. It is shown that for the steam to occupy a considerable region around the well when the bed is in service, it is necessary that the initial state of water be close to that of steam generation. Otherwise the front of boiling in the considered regime of heat and mass transfer extends from the well only a little.

  15. Energy efficiency improvement of dryer section heat recovery systems in paper machines – A case study

    OpenAIRE

    Sivill, Leena; Ahtila, Pekka

    2009-01-01

    Abstract Modern paper machines are equipped with heat recovery systems that transfer heat from the humid exhaust air of the paper machine?s dryer section to different process streams. As a result of process changes, the heat recovery systems may operate in conditions far from the original design point, creating a significant potential for energy efficiency improvement. In this paper we demonstrate this potential with a case study of three operating paper machines. Both operational ...

  16. Experimental Efficiency investigation on heat recovery system used in a solar-powered desalination process

    OpenAIRE

    Rachdi, Aouatef; Qoaider, Louy; Ben-Amara, Mahmoud; Guizani, Amenallah

    2012-01-01

    The aim of this work is to experimentally study, the effect of the heat recovery on water production in a solar desalination process that is working with multiple stage humidification technique. The water production, the temperature and the humidity were tested for such a pilot plant, which operates without and with a heat recovery system. The humidifier efficiency increases with the number of the operating heat exchangers and cannot normally exceed 45% when the system operates wi...

  17. Experimental Study of Thermoelectric Heat Pump Water Heater with Exhaust Heat Recovery from Kitchens

    Institute of Scientific and Technical Information of China (English)

    LIU Zhong-bing; ZHANG Ling; YANG Zhang; XU Ming; HAN Tian-he

    2009-01-01

    A new kind of thermoelectric heat pump water heater for kitchens exhaust heat recovery was pre-sented,and its performances were investigated under different operating voltages.The experiment results show that the coefficient of performance decreases and the temperature difference between the hot and cold sides be-comes larger with the increase of the operating voltage,but the heating time becomes short.The higher the temperature of water,the greater the temperature difference between the hot and cold sides,leading to a smaller eoeffieient of performance.Under an exhaust temperature of 36℃,the coefficient of performance decreases from 1.66 tO 1.22 when the temperature of water increases from 28℃to 46℃with operating voltage 16 V.Performance tests illustrate that,compared with the conventional electrical water heaters,the new kind of ther-moelectric heat pump water heater is more coefficient.

  18. Techno-economic study of a heat pump enhanced flue gas heat recovery for biomass boilers

    International Nuclear Information System (INIS)

    An active condensation system for the heat recovery of biomass boilers is evaluated. The active condensation system utilizes the flue gas enthalpy exiting the boiler by combining a quench and a compression heat pump. The system is modelled by mass and energy balances. This study evaluates the operating costs, primary energy efficiency and greenhouse gas emissions on an Austrian data basis for four test cases. Two pellet boilers (10 kW and 100 kW) and two wood chip boilers (100 kW and 10 MW) are considered. The economic analysis shows a decrease in operating costs between 2% and 13%. Meanwhile the primary energy efficiency is increased by 3–21%. The greenhouse gas emissions in CO2 equivalents are calculated to 15.3–27.9 kg MWh−1 based on an Austrian electricity mix. The payback time is evaluated on a net present value (NPV) method, showing a payback time of 2–12 years for the 10 MW wood chip test case. - Highlights: • A heat pump was studied to recover both sensible and latent heat of the flue gas. • The economic analysis shows a decrease in operating costs between 2% and 13%. • For a 10 MW wood chip boiler a payback time of 2–12 years was estimated

  19. Identification of thermal boundary conditions in heat exchangers of fluidized bed boilers

    International Nuclear Information System (INIS)

    A CFD simulation was carried out for the platen superheater placed in the combustion chamber of the CFB boiler. Velocity, pressure, and temperature of the steam as well as the temperature of the tube wall with the complex cross section were computed using the ANSYS/CFX software. The direct and inverse problems were solved. In the first inverse problem, the heat transfer coefficient on the flue gas side was determined based on the measured steam temperature at the inlet and outlet of the three pass steam superheater. In the second inverse problem, the inlet steam temperature and the heat transfer coefficient on the flue gas side were estimated using measured steam temperatures at selected locations of the superheater. The first inverse problem was solved iteratively using the secant method. The Levenberg-Marquardt method was used to solve the second inverse problem. At every iteration step, a direct conjugate heat transfer problem was solved using the ANSYS/CFX software. -- Highlights: • Platen superheater in Circulating Fluidized Bed Boilers (CFB Boilers) was modeled using CFD simulation. • Method for determining flue-gas side heat transfer coefficient was developed. • Two inverse heat transfer problems were solved

  20. Performance improvement of a 330MWe power plant by flue gas heat recovery system

    OpenAIRE

    Xu Changchun; Xu Min; Zhao Ming; Liang Junyu; Sai Juncong; Qiu Yalin; Xiang Wenguo

    2016-01-01

    In a utility boiler, the most heat loss is from the exhaust flue gas. In order to reduce the exhaust flue gas temperature and further boost the plant efficiency, an improved indirect flue gas heat recovery system and an additional economizer system are proposed. The waste heat of flue gas is used for high-pressure condensate regeneration heating. This reduces high pressure steam extraction from steam turbine and more power is generated. The waste heat recov...

  1. Recovery of valuable materials from spent NIMH batteries using spouted bed elutriation.

    Science.gov (United States)

    Tanabe, Eduardo H; Schlemmer, Diego F; Aguiar, Mônica L; Dotto, Guilherme L; Bertuol, Daniel A

    2016-04-15

    In recent years, a great increase in the generation of spent batteries occurred. Then, efficient recycling ways and correct disposal of hazardous wastes are necessary. An alternative to recover the valuable materials from spent NiMH batteries is the spouted bed elutriation. The aim of this study was to apply the mechanical processing (grinding and sieving) followed by spouted bed elutriation to separate the valuable materials present in spent NiMH batteries. The results of the manual characterization showed that about 62 wt.% of the batteries are composed by positive and negative electrodes. After the mechanical separation processes (grinding, sieving and spouted bed elutriation), three different fractions were obtained: 24.21 wt.% of metals, 28.20 wt.% of polymers and 42.00 wt.% of powder (the positive and negative electrodes). It was demonstrated that the different materials present in the spent NiMH batteries can be efficiently separated using a simple and inexpensive mechanical processing. PMID:26895722

  2. On the recovery of traveling water waves with vorticity from the pressure at the bed

    CERN Document Server

    Hur, Vera Mikyoung

    2015-01-01

    We propose higher-order approximation formulae recovering the surface elevation from the pressure at the bed and the background shear flow for small-amplitude Stokes and solitary water waves. They offer improvements over the pressure transfer function and the hydrostatic approximation. The formulae compare reasonably well with asymptotic approximations of the exact relation between the pressure at the bed and the surface wave in the zero vorticity case, but they incorporate the effects of vorticity through solutions of the Rayleigh equation. Several examples are discussed.

  3. Volatile organic compound recovery by Brayton cycle Heat Pump

    International Nuclear Information System (INIS)

    Organic solvent emissions from industrial processes are a major source of volatile organic compounds (VOCs). VOCs contribute to the formation of photochemical ozone, a major component of smog. Over 90 percent of the organic solvents used in industry are emitted. Not only does this represent a significant source of air pollution, but it also represents a waste of energy resources. A pound of solvent requires an average of 23,000 Btu of energy to produce, in the form of the feedstock and processing energy expenditures. In 1988, the total amount of solvents emitted in the United States was over 4 billion pounds and represent 100 trillion Btu in energy loss. In the mid-1970's, the 3M Company began developing the Brayton Cycle Heat Pump for solvent recovery (BCSRHP). In 1979, the US Department of Energy (DOE) began a project to fabricate and install a BCSRHP in a 3M plant in Hutchinson, Minnesota. DOE has continued sponsoring the development of a large BCSRHP system with 3M, and NUCON International (NUCON). In 1989 DOE and NUCON, with cosponsorship from the Electric Power Research Institute and Southern California Edison Company began development of a small-scale system for use by small emitters. To obtain data for design of the small-scale system, a small, mobile pilot plant was built by NUCON. Between 1990 and 1991, the pilot plant was demonstrated at four industrial sites in Southern California. The operation of the pilot plant was continuously monitored during the demonstrations, and its ability to remove VOCS, utility consumption and other operating characteristics were recorded and its performance quantified

  4. Compacting of coal for heat recovery ovens, Illawarra Coke Company Pty Ltd., Coalcliffe, NSW, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Wright, R.; Schuecker, F.; Kim, R. [Illawara Coke Company, NSW (Australia)

    2006-07-01

    This paper described a simple method of compacting coal for heat-recovery coke making. Coal carbonization tests in commercial non-recovery coke ovens have shown that coal densities greater than 1100 kg/m{sup 3} were obtained in a simple manner by means of hydraulically actuated compression plates. The tests and the results have significantly increased the level of knowledge regarding compacting technology. The coke produced from the compacted cakes is comparable to well-known qualities from non-recovery coke ovens using top charging technology. The quality of stamp charged heat recovery coke will provide a positive impact on blast furnace performance. 2 refs., 5 figs., 11 photos.

  5. Selection of Heat Recovery Ventilators in Different Climate Zones of China

    Institute of Scientific and Technical Information of China (English)

    ZHONG Ke; ZHAO Jing-de; LIU Jia-ping

    2007-01-01

    Considering four different climate zones in China, an investigation on the choice of heat recovery ventilator for the buildings with little moisture emissions is carried out. The annual composition of energy consumption of air intake for per unitary air ventilation flow rate is evaluated by employing the testing data of climatic parameters in eight selected cities. The analysis shows that the total heat recovery is suitable in a controlled ventilation system with air humidity controlled during heating period of all the climates. For the building without air humidity controlled in winter, the sensible heat recovery ventilators can be used in severe cold and cold regions, and total heat recovery systems are more suitable for energy saving in hot summer and cold winter and hot summer and warm winter regions.

  6. Recovery and purification of chitosanase produced by Bacillus cereus using expanded bed adsorption and central composite design.

    Science.gov (United States)

    de Araújo, Nathália Kelly; Pimentel, Vanessa Carvalho; da Silva, Nayane Macedo Portela; de Araújo Padilha, Carlos Eduardo; de Macedo, Gorete Ribeiro; Dos Santos, Everaldo Silvino

    2016-02-01

    This study presents a system for expanded bed adsorption for the purification of chitosanase from broth extract in a single step. A chitosanase-producing strain was isolated and identified as Bacillus cereus C-01 and used to produce chitosanases. The expanded bed adsorption conditions for chitosanase purification were optimized statistically using STREAMLINE(TM) DEAE and a homemade column (2.6 × 30.0 cm). Dependent variables were defined by the quality criteria purification factor (P) and enzyme yield to optimize the chromatographic process. Statistical analyses showed that the optimum conditions for the maximum P were 150 cm/h load flow velocity, 6.0 cm settled bed height, and 7.36 cm distributor height. Distributor height had a strong influence on the process, considerably affecting both the P and enzyme yield. Optimizing the purification variables resulted in an approximately 3.66-fold increase in the P compared with the value under nonoptimized conditions. This system is promising for the recovery of chitosanase from B. cereus C-01 and is economically viable because it promotes the reduction steps. PMID:26638991

  7. Waste heat recovery in data centres in Finland: a choice between new technology adoption and process change

    OpenAIRE

    Gerova, Elitza

    2014-01-01

    In this Master's thesis was studied the feasibility of waste heat recovery in data centres. The aim was to address the problem with the continuously increasing electricity consumption in data centres, to explore the waste heat recovery opportunities in them and to find out which is the preferred alternative for waste heat recovery in the Finnish data centres. Also, to observe the role of management in influencing the waste heat recovery policies. The study was conducted through a mixe...

  8. Comparative assessment of alternative cycles for waste heat recovery and upgrade

    International Nuclear Information System (INIS)

    Thermally activated systems based on sorption cycles, as well as mechanical systems based on vapor compression/expansion are assessed in this study for waste heat recovery applications. In particular, ammonia-water sorption cycles for cooling and mechanical work recovery, a heat transformer using lithium bromide-water as the working fluid pair to yield high temperature heat, and organic Rankine cycles using refrigerant R245fa for work recovery as well as versions directly coupled to a vapor compression cycle to yield cooling are analyzed with overall heat transfer conductances for heat exchangers that use similar approach temperature differences for each cycle. Two representative cases are considered, one for smaller-scale and lower temperature applications using waste heat at 60 oC, and the other for larger-scale and higher temperature waste heat at 120 oC. Comparative assessments of these cycles on the basis of efficiencies and system footprints guide the selection of waste heat recovery and upgrade systems for different applications and waste heat availabilities. Furthermore, these considerations are used to investigate four case studies for waste heat recovery for data centers, vehicles, and process plants, illustrating the utility and limitations of such solutions. The increased implementation of such waste heat recovery systems in a variety of applications will lead to decreased primary source inputs and sustainable energy utilization. -- Highlights: → Sorption and mechanical pathways for the conversion of waste heat streams to work, cooling, and temperature boosting were investigated. → Waste heat sources including 300 W of energy at 60oC and 1 kW of energy at 120 oC were analyzed. → Up to about seventy percent of the input waste heat can be converted to cooling. → Up to about ten percent can be converted to work. → Up to about 47 percent can be upgraded to a higher temperature.

  9. Soy protein recovery in a solvent-free process using continuous liquid-solid circulating fluidized bed ion exchanger.

    Science.gov (United States)

    Prince, Andrew; Bassi, Amarjeet S; Haas, Christine; Zhu, Jesse X; Dawe, Jennifer

    2012-01-01

    Soy protein concentrates and soy protein isolates act as ingredients in bakery, meat and dairy products, baby formulas, starting materials for spun textured vegetable products, and other nutritional supplements. In this study, the effectiveness of a liquid-solid circulating fluidized bed (LSCFB) ion exchanger is demonstrated for the recovery of soluble soy proteins from full fat and defatted soy flour. Under steady-state operating conditions, about 50% of the proteins could be recovered from the feed streams entering the ion exchanger. The LSCFB was shown to be a promising system for the recovery of soy protein from both defatted and full fat soy flour solutions. As the ion exchange process captures dissolved proteins, the system may offer a less damaging form of processing compared with the acid precipitation process where soy protein aggregates form and functionality is affected. In addition, the LSCFB allows simultaneous adsorption and desorption of the proteins allowing for a continuous operation. No prefiltration of feed containing suspended particles is required as well, because fluidization is used in place of packed bed technology to improve on current ion exchange processes. PMID:22002948

  10. Heat-transfer characteristics of flowing and stationary particle-bed-type fusion-reactor blankets

    International Nuclear Information System (INIS)

    The following five appendices are included: (1) physical properties of materials, (2) thermal entrance length Nusselt number variations, (3) stationary particle bed temperature variations, (4) falling bed experimental data and calculations, and (5) stationary bed experimental data and calculations

  11. Heat-transfer characteristics of flowing and stationary particle-bed-type fusion-reactor blankets

    Energy Technology Data Exchange (ETDEWEB)

    Nietert, R.E.

    1983-02-01

    The following five appendices are included: (1) physical properties of materials, (2) thermal entrance length Nusselt number variations, (3) stationary particle bed temperature variations, (4) falling bed experimental data and calculations, and (5) stationary bed experimental data and calculations. (MOW)

  12. Techno-economic analysis and optimization of the heat recovery of utility boiler flue gas

    International Nuclear Information System (INIS)

    Highlights: • Four typical flue gas heat recovery schemes are quantitatively analyzed. • The analysis considers thermodynamic, heat transfer and hydrodynamics factors. • Techno-economic analysis and optimization design are carried out. • High-stage steam substitute scheme obtains better energy-saving effect. • Large heat transfer area and high flue gas resistances weaken overall performance. - Abstract: Coal-fired power plants in China consume nearly half of available coals, and the resulting CO2 emissions cover over 40% of total national emissions. Therefore, reducing the energy expenditure of coal-fired power plants is of great significance to China’s energy security and greenhouse gas reduction programs. For coal-fired power plants, the temperature of a boiler’s exhaust gas reaches 120–150 °C or even higher. The thermal energy of boiler’s exhaust accounts for approximately 3–8% of the total energy of fuel input. Given these factors, we conducted a techno-economic analysis and optimization design of the heat recovery system using boiler exhaust gas. This research is conformed to the principles of thermodynamic, heat transfer, and hydrodynamics. Based on the data from an existing 1000 MW typical power generation unit in China, four typical flue gas heat recovery schemes are quantitatively analyzed from the thermodynamics perspective. The impacts of flue gas heat recovery on net work output and standard coal consumption rate of various schemes are performed. Furthermore, the transfer area of heat recovery exchanger and the draft fan work increment due to the flue gas pressure drop are analyzed. Finally, a techno-economic analysis of the heat recovery schemes is conducted, and some recommendations on optimization design parameters are proposed, with full consideration of various factors such as the decrease on fuel cost due to energy conservation as well as the investment cost of heat recovery retrofitting. The results revealed that, high

  13. Three-zonal engineering method of heat calculation for fluidized bed furnaces based on data on commercial investigations of heat generation distribution during biomass combustion

    Science.gov (United States)

    Litun, D. S.; Ryabov, G. A.

    2016-02-01

    A three-zonal method of heat calculation of furnaces for combustion of biomass and low-caloric fuel in the fluidized bed is described. The method is based on equations of thermal and material balances that account for heat generation by fuel in the zone, heat-and-mass transfer heat exchange between the furnace media and surfaces that bound the zone, and heat-and-mass transfer between furnace zones. The calculation procedure for heat generation by fuel in the fluidized bed (FB) using the heat generation portion by the fuel is proposed. Based on commercial investigations, the main factors that affect the average temperature in the FB and the portion of fuel heat that is released in the FB are determined. Results of commercial investigations showed that the airflow coefficient in the FB should be recognized as the main operation parameter that affects the average temperature in the FB and, consequently, heat generation in the FB. The gas flow rate in the FB can be marked out as the second factor that affects the consumption degree of oxidizer supplied in the FB. Commercial investigations revealed that mixing is affected by the gas flow rate in the FB and the bed material particle size, which may be changed during the boiler operation because of the agglomeration of particles of sand and ash. The calculation processing of commercial investigations on a KM-75-40M boiler of a CHP-3 of an Arkhangelsk Pulp and Paper Mill (APPM), which was carried out using the inverse problem procedure by means of a developed computer program, determined the range of the fuel heat release share in the FB, which was 0.26-0.45 at an excess air factor of 0.59-0.93 in the bed, and the heat release share in the maximum temperature zone in the total heat release in the superbed space. The heat release share in the bed is determined as an approximating function of the excess air factor in the bed and the fluidization number. The research results can be used during designing boilers with the

  14. The influence of heat accumulation on the surface roughness in powder-bed additive manufacturing

    International Nuclear Information System (INIS)

    The influence of heat accumulation on surface roughness during powder-bed additive manufacturing was investigated. A series of Ti-6Al-4V thin plates were produced by using an identical heat input by electron beam melting® (EBM). Spacing distances of 5 mm, 10 mm, and 20 mm were used. The surface roughness of as-built thin plates was measured using a two-axis profilometer. A numerical model was developed to study the influence of spacing distance on heat accumulation. An inverse relationship between the spacing distance and surface roughness was revealed. The experimental and numerical results showed that the surface quality of buildups could be controlled not only by process parameters, but also by the arrangement of components in the buildup chamber. At a constant spacing distance, an increase in the number of powder layers resulted in the accumulation of more heat between the thin plates. An increase in the spacing distance resulted in an upward translation of the Bearing Area Curve (BAC) toward shallower depths, with a reduced core roughness depth (Rk) and peak height (Rpk). A logarithmic regression equation was established from the experimental data. This equation could be used to predict the surface roughness of parts fabricated by EBM® in the studied range of spacing distances. (paper)

  15. Influence of Compressor Station Waste-Heat Recovery Section on Operational Efficiency of Gas Turbine Drive with Isobaric Heat Supply and Regenerative Heat Utilization

    OpenAIRE

    A. Nesenchuk; V. Romaniuk; A. Аbrazovsky; A. Begliak; T. Ryzhova; V. Begliak; Kuzmin, R.

    2014-01-01

    The possibility to utilize existing secondary energy resources for heat supply of an industrial enterprise has been proposed on the basis of the analysis on operation of compressor stations of a cross-country gas pipe-line. The paper considers an influence of waste heat recovery section on operational efficiency of gas turbine drive with regenerative heat utilization.

  16. Influence of Compressor Station Waste-Heat Recovery Section on Operational Efficiency of Gas Turbine Drive with Isobaric Heat Supply and Regenerative Heat Utilization

    Directory of Open Access Journals (Sweden)

    A. Nesenchuk

    2014-09-01

    Full Text Available The possibility to utilize existing secondary energy resources for heat supply of an industrial enterprise has been proposed on the basis of the analysis on operation of compressor stations of a cross-country gas pipe-line. The paper considers an influence of waste heat recovery section on operational efficiency of gas turbine drive with regenerative heat utilization.

  17. Cooling Performance Improvement of the Heat Driven Type Metal Hydride Refrigerator-Heat Transfer Enhancement Influence of Metal Hydride Sheet Loading Into a Metal Hydride Particle Bed

    OpenAIRE

    Bae, Sangchul; Katsuta, Masafumi; Homma, Ikuto; Morita, Eiji

    2012-01-01

    In the refrigeration and air conditioning fields, the demands of energy conservation and renewable energy have been increased recently. In this study, we aim at the development of the heat driven type metal hydride (abbr., MH) that can be driven by the low temperature exhaust or solar heat under 100ᵒC. In order to use this system commercially, heat transfer enhancement of MH particle bed, activation characteric improvement and production cost reduction of MH must be achieved. In this study, w...

  18. Heat recovery from a thermal energy storage based on the Ca(OH)2/CaO cycle

    International Nuclear Information System (INIS)

    Thermal energy storage is very important in many applications related to the use of waste heat from industrial processes, renewable energies or from other sources. Thermochemical storage is very interesting for long-term storage as it can be carried out at room temperature with no energy losses. Dehydration/hydration cycle of Ca(OH)2/CaO has been applied for thermal energy storage in two types of reactors. One of them was a prototype designed by the authors, and in the other type conventional laboratory glassware was used. Parameters such as specific heats, reaction rate and enthalpy, mass losses and heat release were monitored during cycles. Although in the hydration step water is normally added in vapour phase, liquid water, at 0 deg. C has been used in these experiences. Results indicated that the energy storage system performance showed no significant differences, when we compared several hydration/dehydration cycles. The selected chemical reaction did not exhibit a complete reversibility because complete Ca(OH)2 dehydration, was not achieved. However the system could be used satisfactorily along 20 cycles at least. Heat recovery experiments showed general system behaviour during the hydration step in both types of reactors. The designed prototype was more efficient in this step. Main conclusions suggested carrying out one complete cycle at a higher dehydration temperature to recover total system reversibility. A modification of the prototype design trying to enhance heat transfer from the Ca(OH)2 bed could also be proposed

  19. Experimental study on metal-hydrogen reactions and reaction beds with a view to application in heat transformation

    International Nuclear Information System (INIS)

    Using heat transformation processes, low-value heat can be upgraded. Besides the well-known absorption cycles based on a liquid/vapour working pair, reversible chemical reactions between solids and gases, especially hydride-forming metal-hydrogen reactions can be applied. The theoretical background of these heat transformation processes based on solid-gas-reactions, the functional principles of single and multiple stage devices as well as relationships for possible temperature rises and efficiencies are discussed. The experimental investigations are used to evaluate these reactions with respect to their possible application in heat transformers. The emphasis of this work is the experimental determination of the reaction velocity between hydrogen and LaNi5, CaNi5 and LaNisub(4.63)Alsub(0.37) in powder form in simple reaction beds; this reaction velocity is depending on the heat and mass transfer in the reaction beds. The parameters which are considered are the deviation from the thermodynamik equilibrium, the effective powder density, the heat transfer from and to the place of reaction and the effect of gas flow channels within the reaction beds. Criteria for the application of such reaction beds are the temperatures of the heat transfer fluid as well as the temperatures within the reaction which can be reached during the reaction. The use of powders in the reaction beds leads to reasonably short reaction times, if appropriate gas flow channels are provided; however, the required temperature rise in the heat transfer fluid cannot be reached. (orig./WL)

  20. High temperature heat recovery systems; Les recuperateurs de chaleur a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Martin, L.

    2003-07-15

    A state-of-the-art of high temperature heat recovery systems has been made to highlight the advantages of recovery in different energy cycles, and to compare the different geometries, materials and fabrication processes used by the different manufacturers. This leads to define the criteria that a heat recovery system must satisfy in gas turbine cogeneration applications. The pre-dimensioning of a recovery system has been performed in order to compare different geometries and to evaluate them with respect to the criteria defined in the bibliographic study. Finally, the new configuration of the 'Claire' loop has permitted to experimentally characterize a recovery system with an innovative technology based on an helical geometry. These tests have permitted to obtain the global data of the recovery system (efficiency, pressure drop, global exchange coefficient, friction coefficient, velocity and temperature profiles) and to position it with respect to the criteria defined in the bibliographic study. (J.S.)

  1. Industrial applications study. Volume IV. Industrial plant surveys. Final report. [Waste heat recovery and utilization

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Harry L.; Hamel, Bernard B.; Karamchetty, Som; Steigelmann, William H.; Gajanana, Birur C.; Agarwal, Anil P.; Klock, Lawrence M.; Henderson, James M.; Calobrisi, Gary; Hedman, Bruce A.; Koluch, Michael; Biancardi, Frank; Bass, Robert; Landerman, Abraham; Peters, George; Limaye, Dilip; Price, Jeffrey; Farr, Janet

    1977-01-01

    An initial evaluation of the waste heat recovery and utilization potential in the manufacturing portion of the industrial sector is presented. The scope of this initial phase addressed the feasibility of obtaining in-depth energy information in the industrial sector. Within this phase, the methodology and approaches for data gathering and assessment were established. Using these approaches, energy use and waste heat profiles were developed at the 2-digit level; with this data, waste heat utilization technologies were evaluated. This study represents an important first step in the evaluation of waste heat recovery potential.

  2. Energetic and exergetic analysis of waste heat recovery systems in the cement industry

    International Nuclear Information System (INIS)

    In a typical cement producing procedure, 25% of the total energy used is electricity and 75% is thermal energy. However, the process is characterized by significant heat losses mainly by the flue gases and the ambient air stream used for cooling down the clinker (about 35%–40% of the process heat loss). Approximately 26% of the heat input to the system is lost due to dust, clinker discharge, radiation and convection losses from the kiln and the preheaters. A heat recovery system could be used to increase the efficiency of the cement plant and thus contribute to emissions decrease. The aim of this paper is to examine and compare energetically and exergetically, two different WHR (waste heat recovery) methods: a water-steam Rankine cycle, and an Organic Rankine Cycle (ORC). A parametric study proved that the water steam technology is more efficient than ORC in exhaust gases temperature higher than 310 °C. Finally a brief economic assessment of the most efficient solution was implemented. WHR installations in cement industry can contribute significantly in the reduction of the electrical consumptions operating cost thus being a very attractive investment with a payback period up to 5 years. - Highlights: • This paper presents waste heat recovery as a way to gain energy from the exhaust gases in a cement plant. • Water steam cycle and ORC has been analyzed for waste heat recovery. • The energetic and exergetic evaluation of the two waste heat recovery processes is presented and compared

  3. Performance improvement of a 330MWe power plant by flue gas heat recovery system

    Directory of Open Access Journals (Sweden)

    Xu Changchun

    2016-01-01

    Full Text Available In a utility boiler, the most heat loss is from the exhaust flue gas. In order to reduce the exhaust flue gas temperature and further boost the plant efficiency, an improved indirect flue gas heat recovery system and an additional economizer system are proposed. The waste heat of flue gas is used for high-pressure condensate regeneration heating. This reduces high pressure steam extraction from steam turbine and more power is generated. The waste heat recovery of flue gas decreases coal consumption. Other approaches for heat recovery of flue gas, direct utilization of flue gas energy and indirect flue gas heat recovery system, are also considered in this work. The proposed systems coupled with a reference 330MWe power plant are simulated using equivalent enthalpy drop method. The results show that the additional economizer scheme has the best performance. When the exhaust flue gas temperature decreases from 153℃ to 123℃, power output increases by 6.37MWe and increment in plant efficiency is about 1.89%. For the improved indirect flue gas heat recovery system, power output increases by 5.68MWe and the increment in plant efficiency is 1.69%.

  4. Pyrolysis of municipal sewage sludges in a slowly heating and gas sweeping fixed-bed reactor

    International Nuclear Information System (INIS)

    Highlights: • A fixed-bed reactor with sweeping gas was used to mitigate secondary reactions. • The pyrolysis products reflected the original structures of sludge compositions. • The slow pyrolysis produced high yields of liquid. • The oxygen-containing and nitrogenated compounds were the main liquid products. • The gas and liquid yields correlated with the volatile matter contents in the sludges. - Abstract: The pyrolysis of three municipal sewage sludges was carried out using a slowly heating and gas sweeping fixed-bed reactor in the temperature range between 300 °C and 700 °C. The study was aimed to characterize the gaseous and liquid products derived from three different sewage sludges and mainly to discuss the varieties of sewage sludges on the yields and compositions of the gaseous and liquid products. The pyrolysis in this reactor was observed to produce high yields of liquid (above 40 wt.% at 700 °C) that contained high proportions of oxygen-containing compounds and nitrogenated compounds, with minor monoaromatics and aliphatic compounds. The gas and liquid yields correlated with the volatile matter contents in the sludges. For all three sewage sludges, the oxygenated compounds were the principal liquid compounds which could be produced at a low temperature of 300 °C, while more of nitrogenated compounds and other compounds were formed at 700 °C depending on the varieties of sewage sludges

  5. Modular pebble-bed reactor reforming plant design for process heat

    International Nuclear Information System (INIS)

    This report describes a preliminary design study of a Modular Pebble-Bed Reactor System Reforming (MPB-R) Plant. The system uses one pressure vessel for the reactor and a second pressure vessel for the components, i.e., reformer, steam generator and coolant circulator. The two vessels are connected by coaxial pipes in an arrangement known as the side-by-side (SBS). The goal of the study is to gain an understanding of this particular system and to identify any technical issues that must be resolved for its application to a modular reformer plant. The basic conditions for the MPB-R were selected in common with those of the current study of the MRS-R in-line prismatic fuel concept, specifically, the module core power of 250 MWt, average core power density of 4.1 w/cc, low enriched uranium (LEU) fuel with a 235U content of 20% homogeneously mixed with thorium, and a target burnup of 80,000 MWD/MT. Study results include the pebble-bed core neutronics and thermal-hydraulic calculations. Core characteristics for both the once-through-then-out (OTTO) and recirculation of fuel sphere refueling schemes were developed. The plant heat balance was calculated with 55% of core power allotted to the reformer

  6. Heat Recovery from High Temperature Slags: A Review of Chemical Methods

    OpenAIRE

    Yongqi Sun; Zuotai Zhang; Lili Liu; Xidong Wang

    2015-01-01

    Waste heat recovery from high temperature slags represents the latest potential way to remarkably reduce the energy consumption and CO2 emissions of the steel industry. The molten slags, in the temperature range of 1723–1923 K, carry large amounts of high quality energy. However, the heat recovery from slags faces several fundamental challenges, including their low thermal conductivity, inside crystallization, and discontinuous availability. During past decades, various chemical methods have ...

  7. Heat recovery from Diesel engines: a thermodynamic comparison between Kalina and ORC cycles

    OpenAIRE

    Bombarda, Paola; Invernizzi, Costante; Pietra, Claudio

    2009-01-01

    Abstract In the context of heat recovery for electric power generation, Kalina cycle (a thermodynamic cycle using as working fluid a mixture of water and ammonia) and Organic Rankine Cycle (ORC) represent two different eligible technologies. In this work a comparison between the thermodynamic performances of Kalina cycle and an ORC cycle, using hexamethyldisiloxane as working fluid, was conducted for the case of heat recovery from two Diesel engines, each one with an electrical pow...

  8. Parameter optimization of heat recovery steam generation for hyndai engine h25/33

    OpenAIRE

    MARCHENKO ANDRII PETROVYCH; ALI ADEL HAMZAH; OMAR ADEL HAMZAH

    2016-01-01

    Conducted experimental studies of thermodynamic parameters changes in working environments in Hyundai engine H25/33 when the engine is operating at different times of the year. Obtained regressional dependence to calculate the parameters of working environment in the range of ambient temperature changes from 0 to 40 °C. Based the possibility of use of ICE cooling water in the heat recovery steam generator in its appropriate treatment. Formed mathematical model of the heat recovery steam gener...

  9. Themoeconomic optimization of triple pressure heat recovery steam generator operating parameters for combined cycle plants

    OpenAIRE

    Mohammd Mohammed S.; Petrović Milan V.

    2015-01-01

    The aim of this work is to develop a method for optimization of operating parameters of a triple pressure heat recovery steam generator. Two types of optimization: (a) thermodynamic and (b) thermoeconomic were preformed. The purpose of the thermodynamic optimization is to maximize the efficiency of the plant. The selected objective for this purpose is minimization of the exergy destruction in the heat recovery steam generator (HRSG). The purpose of the ther...

  10. Wind- and stack-assisted mechanical ventilation with heat recovery and night cooling

    OpenAIRE

    Hviid, Christian Anker; Svendsen, Svend

    2012-01-01

    The dual-sided issue of indoor environment and energy consumption have become increasingly important in building design. One possible solution is to ventilate by passive means, such as bystack eect and wind pressure, but this requires the development of new concepts and components. Here we have presented the outline of a heat recovery concept suitable for stack and wind-assistedmechanical ventilation systems with total system pressure losses of 74Pa. The heat recovery concept is based on two ...

  11. Are ORCs a Good Option for Waste Heat Recovery in a Petroleum Refinery?

    OpenAIRE

    Mazetto, Bruno Mitsuo; Silva, Julio Augusto Mendes da; Junior, Silvio De Oliveira

    2015-01-01

    The studies regarding Organic Rankine Cycles (ORCs) have been intensified due to the capacity of these systems to convert low-grade energy sources such as geothermal, solar and industrial waste heat into electricity. In this work optimized configurations of ORCs are compared with conventional options of industrial waste heat recovery such as preheating of boiler feed water and cooling of the gas turbine inlet air using an absorption chiller. The study was focused on the recovery of thermal ex...

  12. Thermodynamic performance analysis and algorithm model of multi-pressure heat recovery steam generators (HRSG) based on heat exchangers layout

    International Nuclear Information System (INIS)

    Highlights: • A general model of multi-pressure HRSG based on heat exchangers layout is built. • The minimum temperature difference is introduced to replace pinch point analysis. • Effects of layout on dual pressure HRSG thermodynamic performances are analyzed. - Abstract: Changes of heat exchangers layout in heat recovery steam generator (HRSG) will modify the amount of waste heat recovered from flue gas; this brings forward a desire for the optimization of the design of HRSG. In this paper the model of multi-pressure HRSG is built, and an instance of a dual pressure HRSG under three different layouts of Taihu Boiler Co., Ltd. is discussed, with specified values of inlet temperature, mass flow rate, composition of flue gas and water/steam parameters as temperature, pressure etc., steam mass flow rate and heat efficiency of different heat exchangers layout of HRSG are analyzed. This analysis is based on the laws of thermodynamics and incorporated into the energy balance equations for the heat exchangers. In the conclusion, the results of the steam mass flow rate, heat efficiency obtained for three heat exchangers layout of HRSGs are compared. The results show that the optimization of heat exchangers layout of HRSGs has a great significance for waste heat recovery and energy conservation

  13. Waste Heat Recovery by Heat Pipe Air-Preheater to Energy Thrift from the Furnace in a Hot Forging Process

    Directory of Open Access Journals (Sweden)

    Lerchai Yodrak

    2010-01-01

    Full Text Available Problem statement: Currently, the heat pipe air-preheater has become importance equipment for energy recovery from industrial waste heat because of its low investment cost and high thermal conductivity. Approach: This purpose of the study was to design, construct and test the waste heat recovery by heat pipe air-preheater from the furnace in a hot brass forging process. The mathematical model was developed to predict heat transfer rate and applied to compute the heat pipe air-preheater in a hot brass forging process. The heat pipe air-preheater was designed, constructed and tested under medium temperature operating conditions with inlet hot gas ranging between 370-420°C using water as the working fluid with 50% filling by volume of evaporator length. Results: The experiment findings indicated that when the hot gas temperature increased, the heat transfer rate also increased. If the internal diameter increased, the heat transfer rate increased and when the tube arrangement changed from inline to staggered arrangement, the heat transfer rate increased. Conclusion/Recommendations: The heat pipe air-preheater can reduced the quantity of using gas in the furnace and achieve energy thrift effectively.

  14. Energy recovery from municipal solid waste and sewage sludge using multi-solid fluidized bed combustion technology

    Science.gov (United States)

    1981-07-01

    The concept is to recover energy as high and low pressure steam, simultaneously. High pressure steam would be generated from flue gas using a conventional tubular boiler. Low pressure steam would be generated by direct contact drying of DSS (as 4 percent solids) with hot sand in a fluidized bed that is an integral part of the MS-FBC process. It is proposed that high pressure steam could be used for district heating or electricity generation. The low pressure steam could be used for close proximity building heat. The results of the investigation show that the MS-FBC process concept for the co-utilization of MSW and DSS is technically feasible and that the thermal efficiency of the process is 76 to 82 percent based on experiments conducted in a 70 to 85 lb/h pilot plant and calculations on three conceptual cases.

  15. Metabolomic profiling of heat stress: hardening and recovery of homeostasis in Drosophila

    DEFF Research Database (Denmark)

    Malmendal, Anders; Overgaard, Johannes; Bundy, Jacob G.;

    2006-01-01

    Frequent exposure of terrestrial insects to temperature variation has led to the evolution of protective biochemical and physiological mechanisms, such as the heat shock response, which markedly increases the tolerance to heat stress. Insight into such mechanisms has, so far, mainly relied on...... selective studies of specific compounds or characteristics or studies at the genomic or proteomic levels. In the present study, we have used untargeted NMR metabolomic profiling to examine the biological response to heat stress in Drosophila melanogaster. The metabolite profile was analyzed during recovery...... homeostasis after subsequent heat stress. Several metabolites were identified as responsive to heat stress and could be related to known physiological and biochemical responses. The time course of the recovery of metabolite homeostasis mirrored general changes in gene expression, showing that recovery follows...

  16. Metabolomic profiling of heat stress: hardening and recovery of homeostasis in Drosophila

    DEFF Research Database (Denmark)

    Malmendal, Anders; Overgaard, Johannes; Bundy, Jacob G;

    2006-01-01

    Frequent exposure of terrestrial insects to temperature variation has led to the evolution of protective biochemical and physiological mechanisms, such as the heat shock response, which markedly increases the tolerance to heat stress. Insight into such mechanisms has, so far, mainly relied on...... selective studies of specific compounds or characteristics or studies at the genomic or proteomic levels. In the present study, we have used untargeted NMR metabolomic profiling to examine the biological response to heat stress in Drosophila melanogaster. The metabolite profile was analyzed during recovery...... homeostasis after subsequent heat stress. Several metabolites were identified as responsive to heat stress and could be related to known physiological and biochemical responses. The time course of the recovery of metabolite homeostasis mirrored general changes in gene expression, showing that recovery follows...

  17. Experimental analysis of energy performance of a ventilated window for heat recovery under controlled conditions

    DEFF Research Database (Denmark)

    Appelfeld, David; Svendsen, Svend

    2011-01-01

    A ventilated window in cold climates can be considered as a passive heat recovery system. This study carried out tests to determine the thermal transmittance of ventilated windows by using the Guarded Hot Box. By testing under defined boundary conditions, the investigation described the heat...... balance of the ventilated window and clarified the methodology for thermal performance evaluation. Comparison between windows with and without ventilation using the window-room-ventilation heat balance revealed that a ventilated window can potentially contribute to energy savings. In addition......, it was found that a significant part of preheating occurred through the window frames, which positively influenced the heat recovery of the window but increased the heat loss. Results also showed that increasing air flow decreased the recovery efficiency until the point when the additional thermal...

  18. Wettability modified nanoporous ceramic membrane for simultaneous residual heat and condensate recovery

    Science.gov (United States)

    Hu, H. W.; Tang, G. H.; Niu, D.

    2016-06-01

    Recovery of both latent heat and condensate from boiler flue gas is significant for improving boiler efficiency and water conservation. The condensation experiments are carried out to investigate the simultaneous heat and mass transfer across the nanoporous ceramic membranes (NPCMs) which are treated to be hydrophilic and hydrophobic surfaces using the semicontinuous supercritical reactions. The effects of typical parameters including coolant flow rate, vapor/nitrogen gas mixture temperature, water vapor volume fraction and transmembrane pressure on heat and mass transfer performance are studied. The experimental results show that the hydrophilic NPCM exhibits higher performances of condensation heat transfer and condensate recovery. However, the hydrophobic modification results in remarkable degradation of heat and condensate recovery from the mixture. Molecular dynamics simulations are conducted to establish a hydrophilic/hydrophobic nanopore/water liquid system, and the infiltration characteristics of the single hydrophilic/hydrophobic nanopore is revealed.

  19. Performance of Helical Coil Heat Recovery Exchanger using Nanofluid as Coolant

    Directory of Open Access Journals (Sweden)

    Navid Bozorgan

    2015-07-01

    Full Text Available Nanofluids are expected to be a promising coolant condidate in chemical processes for heat transfer system size reduction. This paper focuses on reducing the number of turns in a helical coil heat recovery exchanger with a given heat exchange capacity in a biomass heating plant using γ-Al2O3/n-decane nanofluid as coolant. The nanofluid flows through the tubes and the hot n-hexane flows through the shell. The numerical results show that using nanofluid as coolant in a helical coil heat exchanger can reduce the manufacturing cost of the heat exchanger and pumping power by reducing the number of turns of the coil.

  20. Advanced Supermarket Refrigeration/Heat Recovery Systems. Country Report, Denmark

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard; Christensen, K. G.

    Annex 26 is the first international project under the IEA Heat Pump Programme that links refrigeration and heat pump technology. Recovering heat from advanced supermarket refrigeration systems for space and water heating seems obvious and is beneficial for owners and operators. Because the great...... number of supermarkets that offer frozen and chilled food and further growth of this sector may be expected, the amount of energy used for refrigeration is enormous and will likely increase in the near future. Annex 26 analysed several advanced supermarket refrigeration systems and came to remarkable...... provide valuable information for practitioners (designers, installers) and manufactures of supermarket refrigeration systems....

  1. A combined thermodynamic cycle used for waste heat recovery of internal combustion engine

    International Nuclear Information System (INIS)

    In this paper, we present a steady-state experiment, energy balance and exergy analysis of exhaust gas in order to improve the recovery of the waste heat of an internal combustion engine (ICE). Considering the different characteristics of the waste heat of exhaust gas, cooling water, and lubricant, a combined thermodynamic cycle for waste heat recovery of ICE is proposed. This combined thermodynamic cycle consists of two cycles: the organic Rankine cycle (ORC), for recovering the waste heat of lubricant and high-temperature exhaust gas, and the Kalina cycle, for recovering the waste heat of low-temperature cooling water. Based on Peng–Robinson (PR) equation of state (EOS), the thermodynamic parameters in the high-temperature ORC were calculated and determined via an in-house computer program. Suitable working fluids used in high-temperature ORC are proposed and the performance of this combined thermodynamic cycle is analyzed. Compared with the traditional cycle configuration, more waste heat can be recovered by the combined cycle introduced in this paper. -- Highlights: ► We study the energy balance of fuel in internal combustion engine. ► Heat recovery effect of exhaust gas is good when ICE is at a high-load condition. ► We propose a new combined thermodynamic cycle for waste heat of ICE. ► The combined cycle has a higher recovery efficiency than previous configurations.

  2. The diffusion model of fractal heat and mass transfer in fluidized bed a local fractional arbitrary Euler-Lagrange formula

    Directory of Open Access Journals (Sweden)

    Cheng Xu

    2015-01-01

    Full Text Available In this manuscript, the local fractional arbitrary Euler-Lagrange formula are utilized to address the diffusion model of fractal heat and mass transfer in a fluidized bed based on the Fick's law with local fractional vector calculus. This article has been corrected. Link to the correction 10.2298/TSCI150923149E

  3. The diffusion model of fractal heat and mass transfer in fluidized bed a local fractional arbitrary Euler-Lagrange formula

    OpenAIRE

    Cheng Xu; Wang Lin

    2015-01-01

    In this manuscript, the local fractional arbitrary Euler-Lagrange formula are utilized to address the diffusion model of fractal heat and mass transfer in a fluidized bed based on the Fick's law with local fractional vector calculus. This article has been corrected. Link to the correction 10.2298/TSCI150923149E

  4. Heat recovery from wastewater systems; Waermerueckgewinnung aus Abwassersystemen

    Energy Technology Data Exchange (ETDEWEB)

    Wanner, O.

    2004-07-01

    Wastewater contains large amounts of heat energy which can be recovered by means of a heat pump and a heat exchanger installed in the sewer system. Practical problems, which may arise and have been investigated in this research project, are the reduction of the heat transfer efficiency due to heat exchanger fouling and the reduction of the nitrification capacity of downstream wastewater treatment plants due to lower wastewater temperatures. A mathematical model was developed by which the decrease of the wastewater temperature in the treatment plant influent can be determined as a function of the amount of heat energy gathered from the wastewater in the sewer system. By this model the variation in time and space of the wastewater temperature in a sewer pipe is calculated for given hydraulics, geometry and environmental conditions. By analysis of data from a large wastewater treatment plant and simulations with a calibrated model, the effect of lowered influent temperatures on nitrification safety, total nitrogen removal efficiency and ammonium effluent concentrations could be quantified. A procedure is suggested by which the reserve nitrification capacity of an existing treatment plant and the increase of the ammonium effluent concentration resulting from a permanent decrease of the wastewater influent temperature can be estimated. By experiments with a pilot scale heat exchanger in a small wastewater channel, the significance of parameters known to have an effect on fouling was investigated and measures to reduce fouling were tested. The measures tested included controlled variation of the wastewater flow velocity (flushing), coatings and finish of the heat exchanger surface and obstacles mounted on the surface. The best results were obtained by regular short term increases of the flow velocity. By this measure, the efficiency of the fouled heat exchanger, which on the average was 60% of the efficiency of the clean heat exchanger, could repeatedly be raised to an

  5. Design and rating of an evaporator for waste heat recovery organic rankine cycles using SES36

    OpenAIRE

    Kaya, Alihan; Lazova, Marija; De Paepe, Michel

    2015-01-01

    The paper presents a design and rating study of a 4MW evaporator having plain horizontal carbon steel tubes having diameters of 25,4 mm, 31,8 mm and 38 mm, to be used in waste heat recovery via Organic Rankine cycle (ORC). SES36 is chosen as working fluid due to its low boiling point, which makes it suitable for low-grade waste heat recovery with subcritical ORCs. Waste heat carrier industrial air arrives at the evaporator bundle at 280°C. Inlet temperature of the working fluid is 40°C and th...

  6. Industrial Waste Heat Recovery - Potential Applications, Available Technologies and Crosscutting R&D Opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Thekdi, Arvind [E3M Inc, North Potomac, MD (United States); Nimbalkar, Sachin U. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    The purpose of this report was to explore key areas and characteristics of industrial waste heat and its generation, barriers to waste heat recovery and use, and potential research and development (R&D) opportunities. The report also provides an overview of technologies and systems currently available for waste heat recovery and discusses the issues or barriers for each. Also included is information on emerging technologies under development or at various stages of demonstrations, and R&D opportunities cross-walked by various temperature ranges, technology areas, and energy-intensive process industries.

  7. Thermal design analysis of triple-pressure heat recovery steam generator and stream turbine systems

    International Nuclear Information System (INIS)

    A computation routine, capable of performing thermal design analysis of the triple-pressure bottoming System (heat recovery steam generator and steam turbine) of combined cycle power plants, is developed. It is based on thermal analysis of the heat recovery steam generator and estimation of its size and steam turbine power. It can be applied to various parametric analyses including optimized design calculation. This paper presents analysis results for the effects on the design performance of heat exchanger arrangements at intermediate and high temperature parts as well as steam pressures. Also examined is the effect of steam sources for de-aeration on design performance

  8. Increasing oil productivity through electromagnetic induction heating for heavy oil recovery using seawater and ferrofluid

    Energy Technology Data Exchange (ETDEWEB)

    Prama, Agus [Bandung Institute of Technology (Indonesia)

    2011-07-01

    One of the methods to recover heavy oil consists of heating the reservoir electrically to reduce oil viscosity and increase its mobility. The aim of this paper is to present the latest developments in electrical heating technologies. The author proposes electromagnetic induction heating as the best technique if coupled with seawater and ferrofluid. Seawater has the potential to improve oil recovery through increasing water wetness, this capacity also increases with increase in temperature. Oil recovery can also be increased through increasing the salinity of the seawater. On the other hand, ferrofluid generates more heat than seawater when heated by electromagnetic induction and it can be directed to the desired location through the use of multilateral well and crosswell EM monitoring. This paper highlighted the fact that electromagnetic induction heating coupled with seawater and ferrofluid can increase oil productivity.

  9. Investigation of the potential of thermophotovoltaic heat recovery for the Turkish industrial sector

    International Nuclear Information System (INIS)

    Highlights: • This study was to determine the potential of thermophotovoltaic heat recovery for Turkish industrial sector. • It was performed by using actual data for TIS. • Total technical–potential energy heat recovery in the high-temperature industry was estimated as 447.8 PJ/year. • Electricity can be achieved from 22.40 PJ/year to 67.45 PJ/year according to the TPV efficiencies. • This study will be very beneficial in energy policies of countries in terms of the usage of waste heat energy. - Abstract: Thermophotovoltaics (TPV) are the use of the photovoltaic effect to generate electricity from a high-temperature thermal (infrared) source. This study deals with to provide an overview of heat recovery by TPV from industrial high-temperature processes in Turkish industrial sector. The paper reviews the relevant facts about TPV technology and the high-temperature industry and identifies three principle locations for TPV heat recovery. For each location, one example process is assessed in terms of applicability of TPV impact on the existing process and power scale. Knowledge of these factors should contribute to the design of an optimum TPV system. In the TIS, the total technical–potential energy recovery in the high-temperature industry using deployed and demonstrated heat recovery devices for product, flue gas, and wall heat recovery was estimated as 447.8 PJ/year. However, an estimation from 22.40 PJ/year to 67.45 PJ/year can be achieved according to the TPV efficiencies. Also, the paper estimates the range of possible energy savings and the reduction in CO emission using TPV in the high-temperature industry. It is expected that this study will be very beneficial in developing energy policies of countries in terms of the usage of waste energy efficiency

  10. Phosphate enhance recovery from wastewater by mechanism analysis and optimization of struvite settleability in fluidized bed reactor.

    Science.gov (United States)

    Fang, Ci; Zhang, Tao; Jiang, Rongfeng; Ohtake, Hisao

    2016-01-01

    Since phosphorus, a non-renewable and non-substitutable resource, has become the principal contributor and limiting factor to water eutrophication, achieving phosphorus removal and recovery from wastewater is pretty essential. Even though struvite crystallization process has been widely used for phosphate (P) recovery in wastewater treatment, its application is hampered by difficulties controlling small particle size and crystal growth. This study was conducted to control the settleability of struvite by calculating and predicting the struvite-settling percentage (Ps), which is always affected by the initial concentration of P (CP), solution pH (pH), reaction time (t), reaction temperature (T), agitation rate (Ar), and inlet flow velocity (vf) of the fluidized bed reactor. The results showed that the settleability of struvite could be enhanced by increasing T and decreasing pH, Ar, or vf, and would perform worse with overlong t or excessive CP. The dynamic variation process of the solution supersaturated index (SI) combined with the phase equilibrium theory and Ostwald ripening mechanism explained the above results sufficiently. The logistic model was chosen to predict the Ps under multi-factors, but the accuracy needs to be improved. PMID:27573918

  11. Study on heat and mass transfer between a greenhouse considered as a solar air heater and a rock packed bed as ambient control system

    International Nuclear Information System (INIS)

    A general study on heat transfer in dry packed beds is made, with special emphasis in comparing different transient models and in identifying the required conditions by which the attained results are equivalent. The differences in thermal behaviour on packed beds, when simultaneous heat mass transfer occurs as wet air is used as heat transfer fluid and exchanges heat and water with the solid in the bed, is analyzed. We modelize wet packed beds considering them as one dimension adsorbents beds, with dispersive and non-dispersive models, where adsorption, condensation-evaporation and liquid water downward flow from condensate phenomena are present. Models were solved numerically and experiments with a rock bed with dry and wet air through it, were made to test assumptions and to further understand the behavior of the system, obtaining a pretty good agreement between expected and measured profiles of the temperature evolution within the packed bed. As a possible application of the wet rock bed for storage purposes, a forced ventilation greenhouse was characterized as a wet air solar heater and analyzed the energetic potential of storing the heat that has to be rejected during daytime to control the crop ambient conditions, in a rock bed for later use at night for heating. (author)

  12. Application of an Integrated Heat Recovery Technology for Domestic Hot Water Supply System and Air Conditioning

    OpenAIRE

    Chen Yan; Zhang Yufeng

    2013-01-01

    This study is to design an integrated heat recovery and air conditioner system and to investigate the feasibility and the potential performance of this system in changing conditions. Different season conditions and operating modes are studied based on the items of one hotel. In winter, heat recovered from wastewater is used on water heating and air condition and the surplus energy of air conditioner system is used on hot water system in summer. Dynamic energy ...

  13. HT-PEM Fuel Cell System with Integrated Thermoelectric Exhaust Heat Recovery

    OpenAIRE

    Gao, Xin

    2014-01-01

    This thesis presents two case studies on improving the efficiency and the loadfollowing capability of a high temperature polymer electrolyte membrane (HTPEM) fuel cell system by the application of thermoelectric (TE) devices.TE generators (TEGs) are harnessed to recover the system exhaust gas for electricity. For this aim, a heat exchanger based TEG heat recovery subsystem is designed. Instead of optimizing an ordinary rectangular heat exchanger, high efficient and commercialized compact plat...

  14. The Misselhorn Cycle: Batch-Evaporation Process for Efficient Low-Temperature Waste Heat Recovery

    OpenAIRE

    Moritz Gleinser; Christoph Wieland

    2016-01-01

    The concept of the Misselhorn cycle is introduced as a power cycle that aims for efficient waste heat recovery of temperature sources below 100 °C. The basic idea shows advantages over a standard Organic Rankine Cycle (ORC) in overall efficiency and utilization of the heat source. The main characteristic of this cycle is the use of at least three parallel batch evaporators instead of continuous heat exchangers. The operational phases of the evaporators are shifted so that there is always one ...

  15. Study and Design of Waste Heat Recovery using Organic Rankine Cycle

    OpenAIRE

    Seyed Saied Homami; Ahmad Khoshgard; Maryam Momenifar; Hamed Nemati Sayad; Hamidreza Heidarimoghadam

    2016-01-01

    Existing energy crisis in the world has diverted human perspective to the optimum usage of the available energy resources. One of these solutions is waste heat recovery systems[1]. Simultaneous production of fresh water, power and cooling from waste heat improves energy efficiency in industrial applications which could be operated by organic Rankine cycles. In this article, cogeneration of electricity and heat (CHP) in the petrochemical industry, textile and paper production has been reviewed...

  16. Modelling of Evaporator in Waste Heat Recovery System using Finite Volume Method and Fuzzy Technique

    OpenAIRE

    Jahedul Islam Chowdhury; Bao Kha Nguyen; David Thornhill

    2015-01-01

    The evaporator is an important component in the Organic Rankine Cycle (ORC)-based Waste Heat Recovery (WHR) system since the effective heat transfer of this device reflects on the efficiency of the system. When the WHR system operates under supercritical conditions, the heat transfer mechanism in the evaporator is unpredictable due to the change of thermo-physical properties of the fluid with temperature. Although the conventional finite volume model can successfully capture those changes in ...

  17. Relationship between core temperature change during recovery and prognosis in classic heat stroke rat models

    OpenAIRE

    Liu, Ya-Nan; Geng, Yan; Fu, Wei; Na PENG; Zheng-tao GU; Su, Lei

    2013-01-01

    Objective To construct classic heat stroke rat models, and observe the changes of body temperature in the recovery period after heat stress to explore its relationship with prognosis. Methods Sixty male SD rats were randomly divided into heat stroke group (HS group, n=50) and control group (C group, n=10). Rats in HS group were exposed to 39℃ heat stress. Core temperature and systolic blood pressure (SBP) of rats were monitored until it reached diagnostic criteria of heat stroke. The core bod...

  18. Ventilation Heat Recovery from Wood-Burning Domestic Flues. A Theoretical Analysis Based on a Triple Concentric Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Lionel Druette

    2013-01-01

    Full Text Available This paper presents a new air-heating system concept for energy-efficient dwellings. It is a system designed to heat a low-energy building by coupling a heat-recovery ventilation system with a three-fluid heat exchanger located on the chimney of a wood-pellet stove. The proposed work focuses on the heat transfer that occurs between flue gases, the ventilation air and the combustion air within a triple concentric tube heat exchanger with no insulation at its outer surface. The main objective is to predict outlet temperature for the specific geometry of the heat exchanger studied here. Thus, the governing differential equations are derived for a counter-co-current flow arrangement of the three fluids. Then analytical solutions for the steady-state temperature distribution are obtained as well as the amount of heat transferred to the outside. An expression for the effectiveness of the heat exchanger is also proposed. Based on these results, calculations are performed on a case study to predict the fluid temperature distribution along the heat exchanger. Finally, a parametric study is carried out on this case study to assess the influence of the relevant parameters on the effectiveness of the heat exchanger. In addition, computation of heat losses to the outside justifies whether insulation is needed.

  19. Recovery of low temperature heat in oil mills

    Directory of Open Access Journals (Sweden)

    Carré Patrick

    2012-11-01

    Full Text Available Energy consumption in oil mills is a major item of costs and a sensitive point in the production of biofuels. To improve their performance, industrials can recover lowtemperature heat thanks to a new technology of heat exchangers suitable for treating granular solid materials. Information about the energy requirements of the rapeseed crushing being not readily available, the article gives a detailed assessment of consumption items (per ton of seed: 263 MJ for preparation operations and 284 MJ for solvent extraction. These exchangers used as pre-conditioners saves about 55 MJ.t−1 of heat by use of steam condensates. We could go further in use of these devices on the one hand to recover heat from press cake and meal, and secondly to use recovered energy to dry and warm up the seeds before pre-pressing. In this configuration, the energy savings could reach 38% of current needs.

  20. Recovery of low temperature heat in oil mills

    OpenAIRE

    Carré Patrick

    2012-01-01

    Energy consumption in oil mills is a major item of costs and a sensitive point in the production of biofuels. To improve their performance, industrials can recover lowtemperature heat thanks to a new technology of heat exchangers suitable for treating granular solid materials. Information about the energy requirements of the rapeseed crushing being not readily available, the article gives a detailed assessment of consumption items (per ton of seed: 263 MJ for preparation operations and 284 MJ...

  1. Waste heat recovery system with new thermoelectric materials

    OpenAIRE

    Borgström, Fredrik; Coyet, Jonas

    2015-01-01

    Increasing fuel prices, higher demands on "greener" transports and tougher international emission regulations puts requirements on companies in the automotive industry in improving their vehicle fuel efficiency. On a typical heavy duty Scania truck around 30% of the total fuel energy is wasted through the exhaust system in terms of heat dissipated to the environment. Hence, several investigations and experiments are conducted trying to find ways to utilize this wasted heat in what is called a...

  2. Assessment of the Performance of a Ventilated Window Coupled with a Heat Recovery Unit through the Co-Heating Test

    Directory of Open Access Journals (Sweden)

    Ludovico Danza

    2016-01-01

    Full Text Available The aim of the article is to describe the results of an experimental campaign based on the assessment of a heat recovery unit coupled with a dynamic window. Two fully monitored and calibrated outdoor test cells are used, in order to evaluate the energy performance and the related thermal comfort. The former presents a traditional window with double-glazing, aluminum frame and indoor blind and a centrifugal extractor for the air circulation. The latter is equipped with a dynamic window with ventilated and blinded double-glazing provided with a heat exchanger. The connection of the dynamic window and heat recovery unit provides different actions: heat recovery; heat transfer reduction; pre-heating before the exchanger. Different operating configurations allowed the trends of the dynamic system to be assessed in different seasons in terms of energy saving, thermal comfort behavior and energy efficiency. The results showed an overall lower consumption of the innovative system, both in winter and summer, with 20% and 15% energy saving, respectively. In general, the dynamic system provided the best comfort conditions, even if it involves a worse behavior than expected, in the summer season.

  3. Recovery of heat from the refrigeration plant at the Bjoerkaeng stadium in Huddinge

    Energy Technology Data Exchange (ETDEWEB)

    Glas, L.O.

    1984-01-01

    The report describes an investigation of heat recovery from the refrigeration plant at the ice hockey rinks outdoors and in the stadium building at the Bjoerkaeng athletics centre. Heat emitted by the refrigeration plant is utilized for heating of the stadium building and for heating water. The heat recovery was measured and analysed over the period 1.12.78-30.11.79, a net energy saving of approximately 380,000 kWh being achieved. The heat recovery analysis comprises a complete heat balance for the ice hockey rinks, the ice stadium, the water heating and the refrigeration plant. On average, test results are very near the figures produced by calculations. The calculation method described should therfore reproduce with good accuracy the possible energy savings in refrigeration plants for ice rinks both indoors and outdoors, of widely differing sizes and geographical location. For instance, the calculation takes into account the effect of the ice stadium temperature selected on the net energy saving and the recoverable quantity of heat.

  4. An Analytical Solution Applied to Heat and Mass Transfer in a Vibrated Fluidised Bed Dryer

    Energy Technology Data Exchange (ETDEWEB)

    Picado, Apolinar

    2011-07-01

    A mathematical model for the drying of particulate solids in a continuous vibrated fluidised bed dryer was developed and applied to the drying of grain wetted with a single liquid and porous particles containing multicomponent liquid mixtures. Simple equipment and material models were applied to describe the process. In the plug-flow equipment model, a thin layer of particles moving forward and well mixed in the direction of the gas flow was regarded; thus, only the longitudinal changes of particle moisture content and composition as well as temperature along the dryer were considered. Concerning the material model, mass and heat transfer in a single isolated particle was studied. For grain wetted with a single liquid, mass and heat transfer within the particles was described by effective transfer coefficients. Assuming a constant effective mass transport coefficient and effective thermal conductivity of the wet particles, analytical solutions of the mass and energy balances were obtained. The variation of both transport coefficients along the dryer was taken into account by a stepwise application of the analytical solution in space intervals with non-uniform inlet conditions and averaged coefficients from previous locations in the dryer. Calculation results were verified by comparison with experimental data from the literature. There was fairly good agreement between experimental data and simulation but the results depend strongly on the correlation used to calculate heat and mass transfer coefficients. For the case of particles containing a multicomponent liquid mixture dried in the vibrated fluidised bed dryer, interactive diffusion and heat conduction were considered the main mechanisms for mass and heat transfer within the particles. Assuming a constant matrix of effective multicomponent diffusion coefficients and thermal conductivity of the wet particles, analytical solutions of the diffusion and conduction equations were obtained. The equations for mass

  5. Fluid flow and heat transfer investigation of pebble bed reactors using mesh adaptive large-eddy simulation

    International Nuclear Information System (INIS)

    A computational fluid dynamics model with anisotropic mesh adaptivity is used to investigate coolant flow and heat transfer in pebble bed reactors. A novel method for implicitly incorporating solid boundaries based on multi-fluid flow modelling is adopted. The resulting model is able to resolve and simulate flow and heat transfer in randomly packed beds, regardless of the actual geometry, starting off with arbitrarily coarse meshes. The model is initially evaluated using an orderly stacked square channel of channel-height-to-particle diameter ratio of unity for a range of Reynolds numbers. The model is then applied to the face-centred cubical geometry. Coolant flow and heat transfer patterns are investigated. (author)

  6. Heat transfer from immersed vertical cylinders in gas-liquid and gas-liquid-solid fluidized beds

    Energy Technology Data Exchange (ETDEWEB)

    Muroyama, Katsuhiko; Okumichi, Shinya; Goto, Yuya; Yamamoto, Yusuke; Saito, Sinobu [Kansai Univ., Suita, Osaka (Japan). Dept. of Chemical Engineering

    2001-08-01

    Heat transfer coefficients are measured using a cylindrical heater vertically immersed in liquid-solid and gas-liquid-solid fluidized beds. The gas used for these investigations was air and the liquids used were water and 0.7 and 1.5 wt-% carboxymethylcellulose aqueous solutions. The authors tried to obtain unified dimensionless correlations for the cylinder surface-to-liquid heat transfer coefficients in the liquid-solid and gas-liquid-solid fluidized beds. It is confirmed that a good analogy exists between the surface-to-liquid heat transfer and mass transfer on the immersed cylinder in the liquid-solid and gas-liquid-solid fluidization systems. (orig.)

  7. Latent x-ray damage in the rat sciatic nerve results in delay in functional recovery after a heat treatment

    International Nuclear Information System (INIS)

    The influence of X-irradiation on the sensitivity of the rat sciatic nerve to local hyperthermia was investigated. Irradiation (35 Gy) of a nerve segment, which included the heated part, resulted in a delayed recovery from heat treatment compared to controls (heat only). The time interval and sequence between irradiation and hyperthermia hardly influenced recovery delay. The size of the irradiated nerve segment did influence recovery delay. Irradiation of a 20 mm nerve segment led to longer recovery delays then irradiation of a 10 mm segment (5-10 days and 1-5 days respectively). A dose-response relation for irradiation-induced delay in recovery was observed when a large segment (20mm) of nerve was irradiated immediately after heat with a dose ranging from 5 to 40 Gy. The delay in heat recovery was dose-dependent below 20 Gy, but after radiation doses above 20 Gy recovery delay remained almost constant. (author)

  8. Advanced Thermoelectric Materials for Efficient Waste Heat Recovery in Process Industries

    Energy Technology Data Exchange (ETDEWEB)

    Adam Polcyn; Moe Khaleel

    2009-01-06

    The overall objective of the project was to integrate advanced thermoelectric materials into a power generation device that could convert waste heat from an industrial process to electricity with an efficiency approaching 20%. Advanced thermoelectric materials were developed with figure-of-merit ZT of 1.5 at 275 degrees C. These materials were not successfully integrated into a power generation device. However, waste heat recovery was demonstrated from an industrial process (the combustion exhaust gas stream of an oxyfuel-fired flat glass melting furnace) using a commercially available (5% efficiency) thermoelectric generator coupled to a heat pipe. It was concluded that significant improvements both in thermoelectric material figure-of-merit and in cost-effective methods for capturing heat would be required to make thermoelectric waste heat recovery viable for widespread industrial application.

  9. Network analysis of oyster transcriptome revealed a cascade of cellular responses during recovery after heat shock.

    Directory of Open Access Journals (Sweden)

    Lingling Zhang

    Full Text Available Oysters, as a major group of marine bivalves, can tolerate a wide range of natural and anthropogenic stressors including heat stress. Recent studies have shown that oysters pretreated with heat shock can result in induced heat tolerance. A systematic study of cellular recovery from heat shock may provide insights into the mechanism of acquired thermal tolerance. In this study, we performed the first network analysis of oyster transcriptome by reanalyzing microarray data from a previous study. Network analysis revealed a cascade of cellular responses during oyster recovery after heat shock and identified responsive gene modules and key genes. Our study demonstrates the power of network analysis in a non-model organism with poor gene annotations, which can lead to new discoveries that go beyond the focus on individual genes.

  10. Control of Single-room Ventilation with Regenerative Heat Recovery for Indoor Climate and Energy Performance

    DEFF Research Database (Denmark)

    Smith, Kevin Michael; Svendsen, Svend

    2016-01-01

    constructions and will soon require 85%. The development of single-room ventilation units may aim for these requirements as a result. The exhaust temperatures in highly efficient heat exchangers may approach outdoor levels. The cold exhaust cannot contain ample moisture, so vapour will condense on the heat......The Danish government will seek energy-efficiency improvements to meet their targeted aims. Single-room ventilation with heat recovery allows simple installation through the façade and may be broadly deployed in apartments. Danish building regulations require greater than 80% heat recovery in new...... exchanger. Available literature suggests that uncoated rotary heat exchangers transfer this condensate to the supply air, so the drying capacity of the ventilation system may be severely limited. This could raise indoor relative humidities to unsafe levels, which could promote the growth of dust...

  11. Process integration in bioprocess indystry: waste heat recovery in yeast and ethyl alcohol plant

    International Nuclear Information System (INIS)

    The process integration of the bioprocess plant for production of yeast and alcohol was studied. Preliminary energy audit of the plant identified the huge amount of thermal losses, caused by waste heat in exhausted process streams, and reviled the great potential for energy efficiency improvement by heat recovery system. Research roadmap, based on process integration approach, is divided on six phases, and the primary tool used for the design of heat recovery network was Pinch Analysis. Performance of preliminary design are obtained by targeting procedure, for three process stream sets, and evaluated by the economic criteria. The results of process integration study are presented in the form of heat exchanger networks which fulfilled the utilization of waste heat and enable considerable savings of energy in short payback period.

  12. Effect of foam on temperature prediction and heat recovery potential from biological wastewater treatment.

    Science.gov (United States)

    Corbala-Robles, L; Volcke, E I P; Samijn, A; Ronsse, F; Pieters, J G

    2016-05-15

    Heat is an important resource in wastewater treatment plants (WWTPs) which can be recovered. A prerequisite to determine the theoretical heat recovery potential is an accurate heat balance model for temperature prediction. The insulating effect of foam present on the basin surface and its influence on temperature prediction were assessed in this study. Experiments were carried out to characterize the foam layer and its insulating properties. A refined dynamic temperature prediction model, taking into account the effect of foam, was set up. Simulation studies for a WWTP treating highly concentrated (manure) wastewater revealed that the foam layer had a significant effect on temperature prediction (3.8 ± 0.7 K over the year) and thus on the theoretical heat recovery potential (30% reduction when foam is not considered). Seasonal effects on the individual heat losses and heat gains were assessed. Additionally, the effects of the critical basin temperature above which heat is recovered, foam thickness, surface evaporation rate reduction and the non-absorbed solar radiation on the theoretical heat recovery potential were evaluated. PMID:27017195

  13. Effect of pH on Thermoanaerobacterium thermosaccharolyticum DSM 571 growth, spore heat resistance and recovery.

    Science.gov (United States)

    Mtimet, Narjes; Guégan, Stéphanie; Durand, Lucile; Mathot, Anne-Gabrielle; Venaille, Laurent; Leguérinel, Ivan; Coroller, Louis; Couvert, Olivier

    2016-05-01

    Thermophilic spore-forming bacteria are potential contaminants in several industrial sectors involving high temperatures (40-65 °C) in the manufacturing process. Among those thermophilic spore-forming bacteria, Thermoanaerobacterium thermosaccharolyticum, called "the swelling canned food spoiler", has generated interest over the last decade in the food sector. The aim of this study was to investigate and to model pH effect on growth, heat resistance and recovery abilities after a heat-treatment of T. thermosaccharolyticum DSM 571. Growth and sporulation were conducted on reinforced clostridium media and liver broth respectively. The highest spore heat resistances and the greatest recovery ability after a heat-treatment were obtained at pH condition allowing maximal growth rate. Growth and sporulation boundaries were estimated, then models using growth limits as main parameters were extended to describe and quantify the effect of pH on recovery of injured spores after a heat-treatment. So, cardinal values were used as a single set of parameters to describe growth, sporulation and recovery abilities. Besides, this work suggests that T. thermosaccharolyticum preserve its ability for germination and outgrowth after a heat-treatment at a low pH where other high resistant spore-forming bacteria like Geobacillus stearothermophilus are unable to grow. PMID:26742617

  14. Solar and heat recovery window element. Solar- und Waermerueckgewinnungs-Fensterscheibenelement

    Energy Technology Data Exchange (ETDEWEB)

    Teuber, P.

    1979-10-18

    The solar and heat recovery window element consists of 2 insulating glass windows, which are separated by a square sealing frame, and so form a chamber for the solar liquid to flow through. There is a collecting pipe with return connection in the top part of the sealed frame, and there is a distributor pipe with incoming connection with the appropriate seals in the top part. The incoming or return pipe is laid in the window frame. The inner and outer insulating glass windows are used to insulate the room and to insulate or produce a solar and heat recovery chamber. The inner insulating glass window prevents condensation of humidity from the room at lower temperatures of the solar and heat recovery liquid. This window has liquid flowing through it, pumped by a circulating pump. This liquid is not transparent and clear, and is protected against frost. The solar energy absorbed when flowing through the liquid chamber is taken to a heat pump system, and part of the energy is extracted from the liquid there. This is done continuously. If there is no solar energy available, then the system works as a heat recovery system, where energy from the room is absorbed by the liquid and is transported to the heat pump.

  15. Relationship between core temperature change during recovery and prognosis in classic heat stroke rat models

    Directory of Open Access Journals (Sweden)

    Ya-nan LIU

    2013-11-01

    Full Text Available Objective To construct classic heat stroke rat models, and observe the changes of body temperature in the recovery period after heat stress to explore its relationship with prognosis. Methods Sixty male SD rats were randomly divided into heat stroke group (HS group, n=50 and control group (C group, n=10. Rats in HS group were exposed to 39℃ heat stress. Core temperature and systolic blood pressure (SBP of rats were monitored until it reached diagnostic criteria of heat stroke. The core body temperature and survival were continuously monitored until 72h. The risk factors of survival were analyzed by univariate and multivariate Cox regression analyses. Results During the recovery, compared with the control group, the body temperature of the HS rats represented a biphasic change that consisted of an initial hypothermia and a delayed hyperthermia. Univariable analysis showed that both the highest and lowest core body temperatures were correlated with prognosis in the heat stroke rats (P<0.05. Multivariate analysis revealed that both the highest core body temperature (P=0.000, HR=102.386 and lowest core body temperature in the recovery period (P=0.001, HR=0.134 were the independent risk factors for heat stroke. Conclusion In heat stroke rats, the higher the core body temperature and the deeper the depth of hypothermia, the poorer the prognosis. Core body temperature in heat stress and recovery period could serve as prognostic indexes in heat stroke. DOI: 10.11855/j.issn.0577-7402.2013.10.007

  16. Heat and mass transfer during drying of a bed of shrinking particles - Simulation for carrot cubes dried in a spout-fluidized-bed drier

    Energy Technology Data Exchange (ETDEWEB)

    Bialobrzewski, Ireneusz; Zielinska, Magdalena; Markowski, Marek [Department of Agri-Food Process Engineering, University of Warmia and Mazury, Heweliusza 14, 10-718 Olsztyn (Poland); Mujumdar, Arun S. [Department of Mechanical Engineering and Engineering Science Program, National University of Singapore (Singapore)

    2008-09-15

    The purpose of the present study was to develop a model to describe the heat and mass transfer during the drying of carrot cubes in a spout-fluidized-bed drier. The model took into account the non-homogeneous shrinkage of the material. The Arbitrary Lagrange-Eulerian (ALE) formulation was applied to enter the problem with moving boundaries. Three phases of drying were distinguished according to the behavior of changes in percent local error of estimation: an initial phase of warming up the material - characterized by a low level of error of moisture content prediction, a second phase - characterized by an increase in the error of moisture content prediction and a phase of decreasing error. A simple test of the sensitivity of the model to the changes in heat transfer coefficient was performed in order to improve the ability of the model to predict the changes in moisture content and temperature of dried carrots. The predicted changes in both the moisture content and the temperature of carrot cubes during drying in a spout-fluidized-bed drier indicate that the model can be successfully applied to describe moisture content, temperature and deformation of dried particles in cases when the very high accuracy of moisture content and temperature prediction is not a crucial element of investigation of the drying process. (author)

  17. Technologies for waste heat recovery in off-shore applications

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Haglind, Fredrik; Kandepu, Rambabu; Fermi, Alessandro; Rossetti, Nicola

    2013-01-01

    In off-shore oil and gas platforms the selection of the gas turbine to support the electrical and mechanical demand on site is often a compromise between reliability, efficiency, compactness, low weight and fuel flexibility. Therefore, recovering the waste heat in off-shore platforms presents both...

  18. Independent air dehumidification with membrane-based total heat recovery: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Liang, C.H.; Zhang, L.Z.; Pei, L.X. [Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Education Ministry, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

    2010-03-15

    Fresh air ventilation is helpful for the control of epidemic respiratory disease like Swine flu (H1N1). Fresh air dehumidification systems with energy recovery measures are the key equipments to realize this goal. As a solution, an independent air dehumidification system with membrane-based total heat recovery is proposed. A prototype is built in laboratory. A detailed model is proposed and a cell-by-cell simulation technique is used in simulation to evaluate performances. The results indicate that the model can predict the system accurately. The effects of varying operating conditions like air-flow rates, temperature, and air relative humidity on the air dehumidification rates, cooling powers, electric power consumption, and thermal coefficient of performance are evaluated. The prototype has a COP of 6.8 under nominal operating conditions with total heat recovery. The performance is rather robust to outside weather conditions with a membrane-based total heat exchanger. (author)

  19. Cost Scaling of a Real-World Exhaust Waste Heat Recovery Thermoelectric Generator: A Deeper Dive

    Science.gov (United States)

    Hendricks, Terry J.; Yee, Shannon; LeBlanc, Saniya

    2016-03-01

    Cost is equally important to power density or efficiency for the adoption of waste heat recovery thermoelectric generators (TEG) in many transportation and industrial energy recovery applications. In many cases, the system design that minimizes cost (e.g., the /W value) can be very different than the design that maximizes the system's efficiency or power density, and it is important to understand the relationship between those designs to optimize TEG performance-cost compromises. Expanding on recent cost analysis work and using more detailed system modeling, an enhanced cost scaling analysis of a waste heat recovery TEG with more detailed, coupled treatment of the heat exchangers has been performed. In this analysis, the effect of the heat lost to the environment and updated relationships between the hot-side and cold-side conductances that maximize power output are considered. This coupled thermal and thermoelectric (TE) treatment of the exhaust waste heat recovery TEG yields modified cost scaling and design optimization equations, which are now strongly dependent on the heat leakage fraction, exhaust mass flow rate, and heat exchanger effectiveness. This work shows that heat exchanger costs most often dominate the overall TE system costs, that it is extremely difficult to escape this regime, and in order to achieve TE system costs of 1/W it is necessary to achieve heat exchanger costs of 1/(W/K). Minimum TE system costs per watt generally coincide with maximum power points, but preferred TE design regimes are identified where there is little cost penalty for moving into regions of higher efficiency and slightly lower power outputs. These regimes are closely tied to previously identified low cost design regimes. This work shows that the optimum fill factor F opt minimizing system costs decreases as heat losses increase, and increases as exhaust mass flow rate and heat exchanger effectiveness increase. These findings have profound implications on the design and

  20. Hsp27 enhances recovery of splicing as well as rephosphorylation of SRp38 after heat shock

    OpenAIRE

    Marin Vinader, L.; Shin, C.; Onnekink, C; Manley, J L; Lubsen, N H

    2005-01-01

    A heat stress causes a rapid inhibition of splicing. Exogenous expression of Hsp27 did not prevent that inhibition but enhanced the recovery of splicing afterward. Another small heat shock protein, αB-crystallin, had no effect. Hsp27, but not αB-crystallin, also hastened rephosphorylation of SRp38—dephosphorylated a potent inhibitor of splicing—after a heat shock, although it did not prevent dephosphorylation by a heat shock. The effect of Hsp27 on rephosphorylation of SRp38 required phosphor...

  1. Cost Efficient Optimization Based Supervisory Controller for Supermarket Subsystems with Heat Recovery

    DEFF Research Database (Denmark)

    Minko, Tomasz; Wisniewski, Rafal; Bendtsen, Jan Dimon;

    2015-01-01

    In this paper, we present a simple modelling approach for a thermal system, which consists of heating, ventilation, air conditioning system (HVAC) and a vapor compression cycle (VCC) system, with one loop heat recovery. In addition a simple model for water tank is presented, in which the reclaimed...... heat is stored and/or which can be used for heating purposes of the building. We present a dynamic optimization algorithm that according to the received price signal, occupancy information and ambient temperature minimizes the operation cost of the whole system and distributes set points to local...

  2. Performance of Helical Coil Heat Recovery Exchanger using Nanofluid as Coolant

    OpenAIRE

    Navid Bozorgan

    2015-01-01

    Nanofluids are expected to be a promising coolant condidate in chemical processes for heat transfer system size reduction. This paper focuses on reducing the number of turns in a helical coil heat recovery exchanger with a given heat exchange capacity in a biomass heating plant using γ-Al2O3/n-decane nanofluid as coolant. The nanofluid flows through the tubes and the hot n-hexane flows through the shell. The numerical results show that using nanofluid as coolant in a helical...

  3. Protection of icing for heat recovery units; Vereisungsschutz fuer Waermerueckgewinner

    Energy Technology Data Exchange (ETDEWEB)

    Ammann, Josef [TechEffekt Anstalt, Schaan (Germany)

    2010-05-15

    During the evaluation of ventilation systems according to the energetic efficiency the additional expenditure for the anti-icing is of great importance. Thereby, it has to be differentiated between measures with respect to the ventilation equipment and measures with respect to the ventilation system. As a function of the execution/combination, an additional energy expenditure results due to the heat demand and the expenditure of electricity. The variants result in losses in the comfort and are qualitatively not comparable. It must be considered that the building owner mainly needs the ventilation in the heating season. The investigation described in the contribution supplies a ranking of the measures to the anti-icing from energetic and qualitative view.

  4. Low grade waste heat recovery using heat pumps and power cycles

    International Nuclear Information System (INIS)

    Thermal energy represents a large part of the global energy usage and about 43% of this energy is used for industrial applications. Large amounts are lost via exhaust gases, liquid streams and cooling water while the share of low temperature waste heat is the largest. Heat pumps upgrading waste heat to process heat and cooling and power cycles converting waste heat to electricity can make a strong impact in the related industries. The potential of several alternative technologies, either for the upgrading of low temperature waste heat such as compression-resorption, vapor compression and trans-critical heat pumps, or for the conversion of this waste heat by using organic Rankine, Kalina and trilateral cycle engines, are investigated with regards to energetic and economic performance by making use of thermodynamic models. This study focuses on temperature levels of 45–60 °C as at this temperature range large amounts of heat are rejected to the environment but also investigates the temperature levels for which power cycles become competitive. The heat pumps deliver 2.5–11 times more energy value than the power cycles in this low temperature range at equal waste heat input. Heat engines become competitive with heat pumps at waste heat temperatures at 100 °C and above. - Highlights: • Application of heat pump technology for heating and cooling. • Compression resorption heat pumps operating with large glides approaching 100 K. • Compression-resorption heat pumps with wet compression. • Potential to convert Industrial waste heat to power or high grade heat. • Comparison between low temperature power cycles and heat pumps

  5. Modeling, Estimation, and Control of Waste Heat Recovery Systems

    OpenAIRE

    Luong, David

    2013-01-01

    Energy consumption and efficiency continue to be an area of high interest with the diminishing supply and rising costs of fossil fuels. In the United States, the industrial and transportation sectors consume a significant portion of the resources and total energy, accounting for significant fossil-fuel-related environmental impacts such as greenhouse gas pollution and global warming. It has been estimated that between 20 to 50\\% of the energy consumed is lost as waste heat in the form of ho...

  6. Nano-EngineeredThermoelectric Materials for Waste Heat Recovery

    OpenAIRE

    Saleemi, Mohsin

    2014-01-01

    Energy crisis and thermal management related issues have been highlighted in the modern century due to escalating demands for energy consumption and global warming from fossil fuels. Sustainable and alternative energy sources are an ever growing global concern. Thermoelectric (TE) materials have gained significant interest, due to effective solid-state energy conversion from waste heat to useful electrical energy and vice versa.   Clean, noise-free, and environment-friendly operation of TE de...

  7. Energy efficiency improvement of a Kraft process through practical stack gases heat recovery

    International Nuclear Information System (INIS)

    A process scheme for the optimal recovery of heat from stack gases considering energy and technical constraints has been developed and applied to an existing Kraft pulping mill. A system based on a closed loop recirculation of hot oil is used to recover the heat from stack gases and distribute it to the appropriate cold streams. The recovery of heat from stack gases is part of an overall optimization of the Kraft mill. Tools such as Pinch Analysis and exergy analysis are used to evaluate the process streams. The results indicate that 10.8 MW of heat from stack gases can be reused to heat process streams such as the deaerator water, hot water, drying filtrates, and black liquor. A simulation model of the recirculation loop has been developed to determine the specifications of the recovery system. The total heat exchanger surface area required by the system is 3460 m2, with a hot oil recirculation temperature of 137 oC. The anticipated total investment is $10.3 M, with a payback time of 1.8 years. - Highlights: → We developed a process design for recovering heat from stack gases in a Kraft mill. → The recovered heat is optimally distributed to the process cold streams. → Heat recovery system has a total surface area of 3500 m2 without gases condensation. → A reduction of 7 percent in total process steam demand is anticipated. → A total investment of 10.3 M$ is needed with a payback time of less than two years

  8. Georgia Pacific: Crossett Mill Identifies Heat Recovery Projects and Operational Improvements

    Energy Technology Data Exchange (ETDEWEB)

    None

    2003-10-01

    An assessment team conducted a mill-wide energy survey at Georgia-Pacific's Crossett, Arkansas mill to update a previous pinch analysis. Three heat recovery projects were identified that could reduce annual costs by $4.8 million and reduce natural gas use by 1,845,000 x 106 Btu. The overall payback period for the heat recovery projects would be less than 1 year. Furthermore, by implementing operational improvements, the mill could save $4.8 million more annually and 1,500,000 x 106 Btu in natural gas.

  9. Prediction of heat recovery characteristics of oxyfuel combustion boiler using CFD

    Energy Technology Data Exchange (ETDEWEB)

    Takafuji, Makoto; Suda, Toshiyuki; Ito, Takamasa [IHI Corporation, Yokohama (Japan). Heat and Fluid Dynamics Dept.; Yamada, Toshihiko [IHI Corporation, Tokyo (Japan). Power Plant Div.

    2013-07-01

    Oxyfuel combustion is one of the promising technologies to reduce CO{sub 2} emission from pulverized coal fired power plant. In order to apply this technology to the commercial boiler, it is important to predict the boiler performance (especially heat recovery characteristics) in Oxyfuel combustion condition. In this study, prediction of heat recovery characteristics of Oxyfuel combustion boiler using CFD was conducted. As a result, it was shown that the same boiler performance can be achieved in Oxyfuel combustion mode as that in Air combustion mode.

  10. Waste Heat Powered Ammonia Absorption Refrigeration Unit for LPG Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Donald C, Energy Concepts Co.; Lauber, Eric, Western Refining Co.

    2008-06-20

    An emerging DOE-sponsored technology has been deployed. The technology recovers light ends from a catalytic reformer plant using waste heat powered ammonia absorption refrigeration. It is deployed at the 17,000 bpd Bloomfield, New Mexico refinery of Western Refining Company. The technology recovers approximately 50,000 barrels per year of liquefied petroleum gas that was formerly being flared. The elimination of the flare also reduces CO2 emissions by 17,000 tons per year, plus tons per year reductions in NOx, CO, and VOCs. The waste heat is supplied directly to the absorption unit from the Unifiner effluent. The added cooling of that stream relieves a bottleneck formerly present due to restricted availability of cooling water. The 350oF Unifiner effluent is cooled to 260oF. The catalytic reformer vent gas is directly chilled to minus 25oF, and the FCC column overhead reflux is chilled by 25oF glycol. Notwithstanding a substantial cost overrun and schedule slippage, this project can now be considered a success: it is both profitable and highly beneficial to the environment. The capabilities of directly-integrated waste-heat powered ammonia absorption refrigeration and their benefits to the refining industry have been demonstrated.

  11. Performance evaluation and experiment system for waste heat recovery of diesel engine

    International Nuclear Information System (INIS)

    In this paper, a waste heat recovery system is proposed where a high speed turbocharged diesel engine acts as the topper of a combined cycle with exhaust gases used for a bottoming Rankine cycle. The paper describes a mathematical model to evaluate the performance of Rankine cycle system with a reciprocating piston expander. The paper focuses on the performance evaluation and parameter selection of the heat exchanger and reciprocating piston expander that are suitable to waste heat recovery of ICE (internal combustion engine). The paper also describes the experimental setup and the preliminary results. The simulation results show that a proper intake pressure should be 4–5 MPa at its given mass flow rate of 0.015–0.021 kg/s depending on the waste heat recovery of a turbocharged diesel engine (80 kW/2590 rpm). The net power and net power rise rate at various ICE rotation speeds are calculated. The result shows that introducing heat recovery system can increase the engine power output by 12%, when diesel engine operates at 80 kW/2590 rpm. The preliminary experimental results indirectly prove the simulation model by two negative work loops in the P–V curve, under a low intake pressure and steam flow rate condition. - Highlights: • We investigate waste heat recovery through secondary fluid power cycle. • We establish a thermodynamic model of reciprocating steam engine. • We conduct the performance evaluation and experimental system development. • Primary parameters of the heat exchangers and expander are determined

  12. A Thermoelectric Waste-Heat-Recovery System for Portland Cement Rotary Kilns

    Science.gov (United States)

    Luo, Qi; Li, Peng; Cai, Lanlan; Zhou, Pingwang; Tang, Di; Zhai, Pengcheng; Zhang, Qingjie

    2015-06-01

    Portland cement is produced by one of the most energy-intensive industrial processes. Energy consumption in the manufacture of Portland cement is approximately 110-120 kWh ton-1. The cement rotary kiln is the crucial equipment used for cement production. Approximately 10-15% of the energy consumed in production of the cement clinker is directly dissipated into the atmosphere through the external surface of the rotary kiln. Innovative technology for energy conservation is urgently needed by the cement industry. In this paper we propose a novel thermoelectric waste-heat-recovery system to reduce heat losses from cement rotary kilns. This system is configured as an array of thermoelectric generation units arranged longitudinally on a secondary shell coaxial with the rotary kiln. A mathematical model was developed for estimation of the performance of waste heat recovery. Discussions mainly focus on electricity generation and energy saving, taking a Φ4.8 × 72 m cement rotary kiln as an example. Results show that the Bi2Te3-PbTe hybrid thermoelectric waste-heat-recovery system can generate approximately 211 kW electrical power while saving 3283 kW energy. Compared with the kiln without the thermoelectric recovery system, the kiln with the system can recover more than 32.85% of the energy that used to be lost as waste heat through the kiln surface.

  13. Thermochemical recovery of heat contained in flue gases by means of bioethanol conversion

    Science.gov (United States)

    Pashchenko, D. I.

    2013-06-01

    In the present paper consideration is being given to the use of bioethanol in the schemes of thermochemical recovery of heat contained in exit flue gases. Schematic diagrams illustrate the realization of thermochemical heat recovery by implementing ethanol steam conversion and conversion of ethanol by means of products of its complete combustion. The feasibility of attaining a high degree of recovery of heat contained in flue gases at the moderate temperature (up to 450°C) of combustion components is demonstrated in the example of the energy balance of the system for thermochemical heat recovery. The simplified thermodynamic analysis of the process of ethanol steam conversion was carried out in order to determine possible ranges of variation of process variables (temperature, pressure, composition) of a reaction mixture providing the efficient heat utilization. It was found that at the temperature above 600 K the degree of ethanol conversion is near unity. The equilibrium composition of products of reaction of ethanol steam conversion has been identified for different temperatures at which the process occurs at the ratio H2O/EtOH = 1 and at the pressure of 0.1 MPa. The obtained results of calculation agree well with the experimental data.

  14. Opportunities for low-grade heat recovery in the UK food processing industry

    International Nuclear Information System (INIS)

    Energy efficiency in the process industry is becoming an increasingly important issue due to the rising costs of both electricity and fossil fuel resources, as well as the tough targets for the reduction in greenhouse gas emissions outlined in the Climate Change Act 2008. Utilisation of waste heat sources is key to improving industrial energy efficiency, with an estimated 11.4 TWh of recoverable heat being wasted each year, a quarter of which is from the food and drinks processing sector. This paper examines the low-grade waste heat sources common to the food and drinks processing sector and the various opportunities for the use of this heat. A review of the best available technologies for recovery of waste heat is provided, ranging from heat transfer between source and sink, to novel technologies for the generation of electricity and refrigeration. Generally, the most economic option for waste heat recovery is heat exchange between nearby/same process source and sink, with a number of well-developed heat exchangers widely available for purchase. More novel options, such as the use of organic Rankine cycles for electricity generation prove to be less economical due to high capital outlays. However, with additional funding provision for demonstration of such projects and development of modular units, such technologies would become more common

  15. Control aspects of latent heat storage and recovery in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T.; Hawes, D.W.; Banu, D.; Feldman, D. [Department of Building, Civil and Environmental Engineering, Centre for Building Studies, 1455 de Maisonmeuve Blud. w., Concordia University, Montreal (Canada)

    2000-05-15

    This paper presents the results of macro scale tests that compare the thermal storage performance of ordinary concrete blocks with those that have been impregnated with two phase change materials (PCM). One is a commercial Butyl Stearate (Emerest 2326), and the other is a commercial Paraffin (Unicere 55). The comparative characteristics of these PCM - concrete combinations were examined. Also, the effect of air velocity was studied in respect to the control of the rates of heat storage and discharge. This research is an extension of the laboratory scale work in this area, which were carried out in recent years.

  16. Energy efficiency analysis of condensed waste heat recovery ways in cogeneration plant

    International Nuclear Information System (INIS)

    Highlights: • The heating equivalent electricity method is used to analyze energy efficiencies. • Analysis is made combining with the characteristics of the steam turbines. • Main factors affecting energy efficiencies of the common heating ways are analyzed. • Applicability evaluations of the heating ways are made under design conditions. - Abstract: Making full use of condensed waste heat is an effective approach to increase heating capacity and reduce air pollutant emissions of the cogeneration plant. In this article, the heating equivalent electricity method is adopted to evaluate energy efficiencies and applicability of different condensed waste heat recovery ways, such as the condenser, the single-effect lithium bromide absorption heat pump and the bleeding-steam-driven compression heat pump. The following discussion is based on a 300 MW water-cooling steam turbine heating system and a 300 MW air-cooling steam turbine heating system. Combining with the characteristics of the water-cooling steam turbine and the air-cooling steam turbine, main factors affecting energy efficiencies are analyzed. Applicability evaluations of these condensed waste heat recovery ways are made by comparing energy efficiencies with each other under design conditions. Analysis shows that direct heat exchange by the condenser should be given the first priority. The condenser is most suitable to provide basic heating load. For the heat source composed of several steam turbines, the corresponding condensers should be connected in series. The proportion of steam turbines with high backpressures should be controlled due to high energy consumptions and inflexibility of adjustment. When supply water temperature is low, a surplus of bleeding steam pressure causes large irreversible loss in the generator of the single-effect absorption heat pump. A waste of energy grade of the bleeding steam makes the energy efficiency of the single-effect absorption heat pump lower than that of the

  17. Effect of particle size on the average heat-transfer rate from a cylinder in a liquid-penetrated granular bed

    International Nuclear Information System (INIS)

    Data of heat transfer of bodies submerged in a fixed liquid-penetrated granular bed are important for the development of efficient catalytic and helium reactors an hydrogen accumulators based on porous intermetallics. In this work, experimental results on the average heat transfer from a cylinder in a liquid-penetrated granular bed are presented and the dependence of the heat-transfer rate on the particle size in the bed is found. The results of these experiments are important for practical estimation and design of catalytic reactors

  18. Modeling of Waste Heat Recovery System and Effects at Different Engine Operating Conditions

    OpenAIRE

    Tu, Ming; Li, Gangyan; Hu, Jian

    2014-01-01

    The model of waste heat recovery (WHR) system is considered by using the thermodynamics cycle, organic Rankine cycle (ORC), to reutilize the waste heat from engine exhaust gas. The model was validated and then applied to different operating conditions. From the results, it could be seen that the working fluid mass flow rate, engine speed, and system pressure would determine the output power and thermal efficiency; the working fluid mass flow rate need not be fixed at a certain point, but a wi...

  19. Retrofit of heat exchanger networks with pressure recovery of process streams at sub-ambient conditions

    International Nuclear Information System (INIS)

    Highlights: • New mathematical model for heat exchanger networks retrofit with pressure recovery. • Optimal heat and work integration applied to the retrofit of sub-ambient processes. • Streams pressure manipulation is used to enhance heat integration of the system. • Compressors and turbines can act on a coupling shaft and/or as stand-alone equipment. • Use of smaller amount of cold utilities, reducing significantly the operational costs. - Abstract: This paper presents a new mathematical programming model for the retrofit of heat exchanger networks (HENs), wherein the pressure recovery of process streams is conducted to enhance heat integration. Particularly applied to cryogenic processes, HENs retrofit with combined heat and work integration is mainly aimed at reducing the use of expensive cold services. The proposed multi-stage superstructure allows the increment of the existing heat transfer area, as well as the use of new equipment for both heat exchange and pressure manipulation. The pressure recovery of streams is carried out simultaneously with the HEN design, such that the process conditions (streams pressure and temperature) are variables of optimization. The mathematical model is formulated using generalized disjunctive programming (GDP) and is optimized via mixed-integer nonlinear programming (MINLP), through the minimization of the retrofit total annualized cost, considering the turbine and compressor coupling with a helper motor. Three case studies are performed to assess the accuracy of the developed approach, including a real industrial example related to liquefied natural gas (LNG) production. The results show that the pressure recovery of streams is efficient for energy savings and, consequently, for decreasing the HEN retrofit total cost especially in sub-ambient processes

  20. Analysis of a Rotating Spool Expander for Organic Rankine Cycles in Heat Recovery Applications

    OpenAIRE

    Krishna, Abhinav; Bradshaw, Craig R.; Eckhard A. Groll

    2014-01-01

    The increasing cost of energy, coupled with the recent drive for energy security and climate change mitigation have provided the impetus for harnessing renewable energy sources as viable alternatives to conventional fossil fuels. Furthermore, recovering heat that is discharged from power plants, automobiles and various other industrial processes is of growing interest. Nevertheless, technologies attempting to provide small-scale heat recovery solutions have seen very limited commercialization...

  1. Optimization of Thermoelectric Components for Automobile Waste Heat Recovery Systems

    Science.gov (United States)

    Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.

    2015-10-01

    For a typical spark ignition engine approximately 40% of available thermal energy is lost as hot exhaust gas. To improve fuel economy, researchers are currently evaluating technology which exploits exhaust stream thermal power by use of thermoelectric generators (TEGs) that operate on the basis of the Seebeck effect. A 5% improvement in fuel economy, achieved by use of TEG output power, is a stated objective for light-duty trucks and personal automobiles. System modeling of thermoelectric (TE) components requires solution of coupled thermal and electric fluxes through the n and p-type semiconductor legs, given appropriate thermal boundary conditions at the junctions. Such applications have large thermal gradients along the semiconductor legs, and material properties are highly dependent on spatially varying temperature profiles. In this work, one-dimensional heat flux and temperature variations across thermoelectric legs were solved by using an iterative numerical approach to optimize both TE module and TEG designs. Design traits were investigated by assuming use of skutterudite as a thermoelectric material with potential for automotive applications in which exhaust gas and heat exchanger temperatures typically vary from 100°C to over 600°C. Dependence of leg efficiency, thermal fluxes and electric power generation on leg geometry, fill fractions, electric current, thermal boundary conditions, etc., were studied in detail. Optimum leg geometries were computed for a variety of automotive exhaust conditions.

  2. A Green Roof Test Bed for Stormwater Management and Reduction of Urban Heat Island Effect in Singapore

    OpenAIRE

    Qin, Xiaosheng; Wu, Xiangyu; Yee-Meng CHIEW; Li, Yanhong

    2013-01-01

    A green roof test bed, established at the Nanyang Technological University in Singapore, was used to investigate its benefit for storm water management and urban heat island effect mitigation. The system comprised 3 units, 2 in the form of vegetated roofs and the other a bare roof. The system was equipped with automatic monitoring devices for measuring the hydrological data. Continuous data monitoring on the roofs was conducted to evaluate the thermal and hydrological effects. The study shows...

  3. Energy saving in ceramic tile kilns: Cooling gas heat recovery

    International Nuclear Information System (INIS)

    A great quantity of thermal energy is consumed in ceramic tile manufacture, mainly in the firing stage. The most widely used facilities are roller kilns, fuelled by natural gas, in which more than 50% of the energy input is lost through the flue gas and cooling gas exhaust stacks. This paper presents a calculation methodology, based on certain kiln operating parameters, for quantifying the energy saving obtained in the kiln when part of the cooling gases are recovered in the firing chamber and are not exhausted into the atmosphere. Energy savings up to 17% have been estimated in the studied case. Comparison of the theoretical results with the experimental data confirmed the validity of the proposed methodology. The study also evidenced the need to improve combustion process control, owing to the importance of the combustion process in kiln safety and energy efficiency. - Highlights: •Some energy input (30–35%) in ceramic roller kilns is lost through the cooling gas stack. •Cooling air is directly recovered in the combustion chamber, providing oxygen. •This energy recovery from the cooling gas stack has been quantified. •It has been proven that the proposed methodology to estimate energy savings is valid

  4. Heat Recovery from High Temperature Slags: A Review of Chemical Methods

    Directory of Open Access Journals (Sweden)

    Yongqi Sun

    2015-03-01

    Full Text Available Waste heat recovery from high temperature slags represents the latest potential way to remarkably reduce the energy consumption and CO2 emissions of the steel industry. The molten slags, in the temperature range of 1723–1923 K, carry large amounts of high quality energy. However, the heat recovery from slags faces several fundamental challenges, including their low thermal conductivity, inside crystallization, and discontinuous availability. During past decades, various chemical methods have been exploited and performed including methane reforming, coal and biomass gasification, and direct compositional modification and utilization of slags. These methods effectively meet the challenges mentioned before and help integrate the steel industry with other industrial sectors. During the heat recovery using chemical methods, slags can act as not only heat carriers but also as catalysts and reactants, which expands the field of utilization of slags. Fuel gas production using the waste heat accounts for the main R&D trend, through which the thermal heat in the slag could be transformed into high quality chemical energy in the fuel gas. Moreover, these chemical methods should be extended to an industrial scale to realize their commercial application, which is the only way by which the substantial energy in the slags could be extracted, i.e., amounting to 16 million tons of standard coal in China.

  5. Waste heat recovery system for recapturing energy after engine aftertreatment systems

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Nelson, Christopher R.

    2014-06-17

    The disclosure provides a waste heat recovery (WHR) system including a Rankine cycle (RC) subsystem for converting heat of exhaust gas from an internal combustion engine, and an internal combustion engine including the same. The WHR system includes an exhaust gas heat exchanger that is fluidly coupled downstream of an exhaust aftertreatment system and is adapted to transfer heat from the exhaust gas to a working fluid of the RC subsystem. An energy conversion device is fluidly coupled to the exhaust gas heat exchanger and is adapted to receive the vaporized working fluid and convert the energy of the transferred heat. The WHR system includes a control module adapted to control at least one parameter of the RC subsystem based on a detected aftertreatment event of a predetermined thermal management strategy of the aftertreatment system.

  6. Polymer spiral film gas-liquid heat exchanger for waste heat recovery in exhaust gases

    OpenAIRE

    Breton, Antoine

    2012-01-01

    In this master thesis report the development of an innovative spiral heat exchanger based on polymer materials is described. Building prototypes, erection of a test bench and firsts tests of the heat exchanger are presented. The heat exchanger prototype survived all tests especially several days in contact with aggressive gases. A facility integrating a Diesel exhaust gases production has been developed to test this heat exchanger design. Performance results obtained during the tes...

  7. APPLICATIONS OF THERMAL ENERGY STORAGE TO WASTE HEAT RECOVERY IN THE FOOD PROCESSING INDUSTRY, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, W. L.; Christenson, James A.

    1979-07-31

    A project is discussed in which the possibilities for economical waste heat recovery and utilization in the food industry were examined. Waste heat availability and applications surveys were performed at two manufacturing plants engaged in low temperature (freezing) and high temperature (cooking, sterilizing, etc.) food processing. The surveys indicate usable waste heat is available in significant quantities which could be applied to existing, on-site energy demands resulting in sizable reductions in factory fuel and energy usage. At the high temperature plant, the energy demands involve the heating of fresh water for boiler make-up, for the food processes and for the daily clean-up operation. Clean-up poses an opportunity for thermal energy storage since waste heat is produced during the one or two production shifts of each working day while the major clean-up effort does not occur until food production ends. At the frozen food facility, the clean-up water application again exists and, in addition, refrigeration waste heat could also be applied to warm the soil beneath the ground floor freezer space. Systems to recover and apply waste heat in these situations were developed conceptually and thermal/economic performance predictions were obtained. The results of those studies indicate the economics of waste heat recovery can be attractive for facilities with high energy demand levels. Small factories, however, with relatively low energy demands may find the economics marginal although, percentagewise, the fuel and energy savings are appreciable.

  8. Optimal waste heat recovery in micro gas turbine cycles through liquid water injection

    International Nuclear Information System (INIS)

    Water injection in the compressor exhaust, to recuperate waste heat, is considered a possible route to improve the electric efficiency and overall performance of the micro Gas Turbine turbine (mGT). Many research exists on water injection in mGTs, however a generic study to determine the optimal route for waste heat recovery is still missing. To determine the optimal cycle settings for waste heat recovery through water injection, we have performed simulations using a two-step method. In a first step, the thermodynamic limit for water injection is sought using a black box method. In a second step, the cycle layout is designed by means of composite curve theory. This paper summarizes the results of two scenarios. In the first scenario, the black box is considered as adiabatic and no fixed stack temperature is imposed (thus allowing condensation of the exhaust gasses). One of the major concerns when injecting water is the water consumption, which can be compensated in some cases through condensation and recycling the condensate. Therefore, in the second scenario, the cycle is made self-sufficient with water. In this case, the black box is no longer considered adiabatic and heat exchange with the environment is allowed for condensation of the flue gasses. Black box simulations showed that lowering the stack temperature to 53 °C results in an injection of 17 %wt of water and an increase in electric efficiency of 9% absolute. To keep the mGT cycle layout simple, low cost and not too complex, a maximum of two heat exchangers was imposed for the heat exchanger network design. Although black box analysis indicated a large potential for water introduction, this potential could not be achieved with the considered networks in this paper. Finally, injection of preheated water was identified as the optimal water injection scheme for waste heat recovery resulting in 4.6% absolute electric efficiency increase and a final stack temperature of 62 °C. Results of simulations of

  9. Heat Recovery Ventilation for Housing: Air-to-Air Heat Exchangers.

    Science.gov (United States)

    Corbett, Robert J.; Miller, Barbara

    The air-to-air heat exchanger (a fan powered ventilation device that recovers heat from stale outgoing air) is explained in this six-part publication. Topic areas addressed are: (1) the nature of air-to-air heat exchangers and how they work; (2) choosing and sizing the system; (3) installation, control, and maintenance of the system; (4) heat…

  10. Performance of Counter Flow Heat Recovery Ventilation Systems in Dwellings Considering the Influence of Uncertainties

    NARCIS (Netherlands)

    Yang, Z.; Cauberg, J.J.M.; Tenpierik, M.J.

    2012-01-01

    Both critical and optimistic claims have been made regarding the performance of heat recovery ventilation systems (HRVS) in dwellings. Such arguments are raised partly because two key aspects are not fully clarified, i.e. the performance criteria and the influence of uncertainties. In the current pa

  11. ORC waste heat recovery in European energy intensive industries: Energy and GHG savings

    International Nuclear Information System (INIS)

    Highlights: • A methodology to estimate ORC industrial heat recovery potential is defined. • Heat recovery applications for different industrial processes are shown. • Cement, steel, glass and oil and gas applications are considered in EU27. • Savings in electricity costs and greenhouse gases are quantified. - Abstract: Organic Rankine Cycle (ORC) is a technology with important opportunities in heat recovery from energy intensive industrial processes. This paper represents the first comprehensive estimate of ORC units that can be installed in cement, steel, glass and oil and gas industries in the 27 countries of the European Union based on an accurate methodology related to real plants in operation or under construction. An evaluation of energy savings, depending on the number of operating hours per year and of the consequent decrease in CO2 emission and electricity expenditure, is also provided. The study, carried out in the framework of an European research project on heat recovery in energy intensive industries, found that, in the most convenient considered scenario, up to about 20,000 GW h of thermal energy per year can be recovered and 7.6 M ton of CO2 can be saved by the application of ORC technology to the investigated and most promising industrial sectors

  12. Integrated energy and emission management for heavy-duty diesel engines with waste heat recovery system

    NARCIS (Netherlands)

    Willems, F.P.T.; Kupper, F.; Rascanu, G.; Feru, E.

    2015-01-01

    Rankine-cycleWasteHeatRecovery (WHR)systems are promising solutions to reduce fuel consumption for trucks. Due to coupling between engine andWHR system, control of these complex systems is challenging. This study presents an integrated energy and emission management strategy for an Euro-VI Diesel en

  13. Optimization of paper machine heat recovery system; Paperikoneen laemmoentalteenottosysteemin optimointi - PMSY 02

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, H. [Valmet Oyj Pansio, Turku (Finland)

    1998-12-31

    Conventionally the energy content of paper and board machine dryer section exhaust air is recovered in the heat recovery tower. This has had a major contribution to the overall energy economy of a paper machine. Modern paper machines have already reached momentary record speeds above 1700 m/min, and speeds above 2000 m/min will be strived to. This is possible by developing new efficient drying technologies. These will require new solutions for the heat recovery systems. At the same time requirements for new heat recovery solutions come from the gradually closing of paper mill water circulation systems. In this project a discrete tool based on optimization is developed, a tool for analyzing, optimizing and dimensioning of paper machine heat recovery systems for different process conditions. Delivery of a paper machine process requires more and more transferring of process knowledge into calculation model parameters. The overall target of the tool is to decrease the energy consumption considering new drying technologies and the gradually closing of water circulation systems. (orig.)

  14. Waste Heat Recovery for the Cement Sector : Market and Supplier Analysis

    OpenAIRE

    International Finance Corporation; Institute for Industrial Productivity

    2014-01-01

    This report analyzes the current status of Waste Heat Recovery (WHR) technology deployment in developing countries and investigates the success factors in countries where WHR has become widely spread. The report then focuses on the in-depth analysis of WHR potential and enabling factors in eleven country markets in Africa (Nigeria, South Africa), South Asia (India, Pakistan), Middle East (...

  15. Local heat transfer properties in co- and counter-current G-L-S magnetically stabilized fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Jinli Zhang; Ming Zhang; Wei Li; Xiaofang Li; Xiangkun Meng; Baoning Zong

    2011-01-01

    Heat transfer coefficients were measured by immersed probes in co- and counter-current G-L-S magnetically stabilized fluidized beds (MSFBs) using air,water and nickel-alloy particles as the gas,liquid and solid phases. Influences of major factors,including magnetic field intensity,superficial gas and liquid velocities,liquid viscosity and surface tension,on heat-transfer properties were studied experimentally,indicating that both co- and counter-current G-L-S MSFB can provide relatively uniform radial distribution of heat transfer coefficients under appropriate operation conditions,thus controlling operation temperature for highly exothermic multi-phase reaction systems. Two correlations were provided to estimate accurately heat transfer properties in both co- and counter-current G-L-S MSFB systems,with an average error of less than 10%.

  16. Stress and recovery assessment during simulated microgravity: Effects of exercise during a long-term head down tilt bed rest in women.

    OpenAIRE

    Karine, Weiss; Nicolas, Michel

    2009-01-01

    The aim of this study was to determine the effects of a 60-day head-down tilt long-term bed rest (HDT) on stress and recovery in sixteen healthy female volunteers. Participants were randomly assigned to either an exercise group (Exe) that followed a training program combining resistive and aerobic exercises, or to a no-exercise control group (Ctl). Psychological states were assessed using the Rest-Q, a validated questionnaire based on stress-recovery responses. A longitudinal analysis reveale...

  17. Waste heat recovery using a thermoelectric power generation system in a biomass gasifier

    International Nuclear Information System (INIS)

    The aim of this study is to investigate the use of waste heat that is recovered from a biomass gasifier. In the gasification process, the low heating value of biomass can be transferred to a high heating value for combustible gaseous fuel, a form that is widely used in industry and power plants. Conventionally, some of cleaning processes need to be conducted under higher operating temperatures that the low temperatures typically used to burn biomass. Therefore, the catalytic reactor was designed before installation the scrubber in the downdraft gasifier system to make effective use of the waste heat. The experimental result shows that the temperature of the gasifier outlet is about 623–773 K; dolomite is used for tar removal in the catalytic reactor. To further improve the use of waste heat, a thermoelectric generator is added to provide for the recovery of waste heat. The thermoelectric generator system is manufactured using a Bi2Te3 based material and is composed of eight thermoelectric modules on the surface of catalytic reactor. The measured surface temperature of the catalytic reactor is 473–633 K that is the correct temperature for Bi2Te3 as thermoelectric generator. The result shows that the maximum power output of the thermoelectric generator system is 6.1 W and thermoelectric generator power density is approximately 193.1 W/m2. - Highlights: • Set up the thermoelectric power generation system to recover waste heat from biomass gasifier. • Bi2Te3 based material is suitable for choosing as a thermoelectric generator in the waste heat recovery temperature range of 473–633 K form gasifier. • The maximum power density can reach 193.1 W/m2 for waste heat recovery

  18. Experimental investigation of a reticulated porous alumina heat exchanger for high temperature gas heat recovery

    International Nuclear Information System (INIS)

    The present study presents an experimental study of a prototype counter-flow heat exchanger designed to recover sensible heat from inert and reactive gases flowing through a high temperature solar reactor for splitting CO2. The tube-in-tube heat exchanger is comprised of two concentric alumina tubes, each filled with reticulated porous alumina with a nominal porosity of 80% and pore density of 5 pores per inch (ppi). The RPC provides high heat transfer surface area per unit volume (917 m−1) with low pressure drop. Measurements include the permeability, inertial coefficient, overall heat transfer coefficient, effectiveness and pressure drop. For laminar flow and an inlet gas temperature of 1240 K, the overall heat transfer coefficients are 36–41 W m−2 K−1. The measured performance is in good agreement with a prior CFD model of the heat exchanger. - Highlights: • A ceramic heat exchanger provides gas-phase heat recuperation for a solar thermochemical reactor. • Alumina reticulated porous ceramic (RPC) provides high surface area and low pressure drop. • Heat transfer and pressure drop are measured at temperatures up to 1240 K. • RPC provides a 9-fold increase in heat transfer compared to bare tubes

  19. Waste heat recovery options in a large gas-turbine combined power plant

    Science.gov (United States)

    Upathumchard, Ularee

    This study focuses on power plant heat loss and how to utilize the waste heat in energy recovery systems in order to increase the overall power plant efficiency. The case study of this research is a 700-MW natural gas combined cycle power plant, located in a suburban area of Thailand. An analysis of the heat loss of the combustion process, power generation process, lubrication system, and cooling system has been conducted to evaluate waste heat recovery options. The design of the waste heat recovery options depends to the amount of heat loss from each system and its temperature. Feasible waste heat sources are combustion turbine (CT) room ventilation air and lubrication oil return from the power plant. The following options are being considered in this research: absorption chillers for cooling with working fluids Ammonia-Water and Water-Lithium Bromide (in comparison) and Organic Rankine Cycle (ORC) with working fluids R134a and R245fa. The absorption cycles are modeled in three different stages; single-effect, double-effect and half-effect. ORC models used are simple ORC as a baseline, ORC with internal regenerator, ORC two-phase flash expansion ORC and ORC with multiple heat sources. Thermodynamic models are generated and each system is simulated using Engineering Equation Solver (EES) to define the most suitable waste heat recovery options for the power plant. The result will be synthesized and evaluated with respect to exergy utilization efficiency referred as the Second Law effectiveness and net output capacity. Results of the models give recommendation to install a baseline ORC of R134a and a double-effect water-lithium bromide absorption chiller, driven by ventilation air from combustion turbine compartment. The two technologies yield reasonable economic payback periods of 4.6 years and 0.7 years, respectively. The fact that this selected power plant is in its early stage of operation allows both models to economically and effectively perform waste heat

  20. Implementation of Exhaust Gas Recirculation for Double Stage Waste Heat Recovery System on Large Container Vessel

    DEFF Research Database (Denmark)

    Andreasen, Morten; Marissal, Matthieu; Sørensen, Kim;

    2014-01-01

    Concerned to push ships to have a lower impact on the environment, the International Maritime Organization are implementing stricter regulation of NOx and SOx emissions, called Tier III, within emission control areas (ECAs). Waste Heat Recovery Systems (WHRS) on container ships consist of...... recovering some of the waste heat from the exhaust gas. This heat is converted into electrical energy used on-board instead of using auxiliary engines. Exhaust Gas Recirculation (EGR) systems, are recirculating a part of the exhaust gas through the engine combustion chamber to reduce emissions. WHRS combined...

  1. Water Recovery with the Heat Melt Compactor in a Microgravity Environment

    Science.gov (United States)

    Golliher, Eric L.; Goo, Jonathan; Fisher, John

    2015-01-01

    The Heat Melt Compactor is a proposed utility that will compact astronaut trash, extract the water for eventual re-use, and form dry square tiles that can be used as additional ionizing radiation shields for future human deep space missions. The Heat Melt Compactor has been under development by a consortium of NASA centers. The downstream portion of the device is planned to recover a small amount of water while in a microgravity environment. Drop tower low gravity testing was performed to assess the effect of small particles on a capillary-based water/air separation device proposed for the water recovery portion of the Heat Melt Compactor.

  2. Heat stress and recovery of photosystem II efficiency in wheat (Triticum aestivum L.) cultivars acclimated to different growth temperatures

    DEFF Research Database (Denmark)

    Haque, Sabibul; Kjær, Katrine Heinsvig; Rosenqvist, Eva; Sharma, Dew Kumari; Ottosen, Carl-Otto

    2014-01-01

    The effect of heat stress on photosystem II (PS II) efficiency and post-stress recovery was studied in four wheat cultivars using chlorophyll fluorescence. The main aim was to examine the cultivar differences in relation to inhibition and recovery of PSII functionality after heat stress at differ...

  3. Cooling energy efficiency and classroom air environment of a school building operated by the heat recovery air conditioning unit

    International Nuclear Information System (INIS)

    The recently-built school buildings have adopted novel heat recovery ventilator and air conditioning system. Heat recovery efficiency of the heat recovery facility and energy conservation ratio of the air conditioning unit were analytically modeled, taking the ventilation networks into account. Following that, school classroom displacement ventilation and its thermal stratification and indoor air quality indicated by the CO2 concentration have been numerically modeled concerning the effects of delivering ventilation flow rate and supplying air temperature. Numerical results indicate that the promotion of mechanical ventilation rate can simultaneously boost the dilution of indoor air pollutants and the non-uniformity of indoor thermal and pollutant distributions. Subsequent energy performance analysis demonstrates that classroom energy demands for ventilation and cooling could be reduced with the promotion of heat recovery efficiency of the ventilation facility, and the energy conservation ratio of the air conditioning unit decreases with the increasing temperatures of supplying air. Fitting correlations of heat recovery ventilation and cooling energy conservation have been presented. - Highlights: • Low energy school buildings and classroom environment. • Heat recovery facility operating with an air conditioning unit. • Displacement ventilation influenced by the heat recovery efficiency. • Energy conservation of cooling and ventilation through heat recovery. • Enhancement of classroom environment with reduction of school building energy

  4. New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

    International Nuclear Information System (INIS)

    Highlights: • Thermal and heat transfer models of absorption heat pumps driven by exhaust gas, hot water, or natural gas. • Natural gas boiler combustion model. • Heat exchanger for condensing. • Experimental data of a hot water absorption heat pump. • Economic assessment of heat recovery absorption heat pump for improving natural gas boilers. - Abstract: Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150–200 °C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50–60 °C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural

  5. Design and analysis of a cogeneration plant using heat recovery of a cement factory

    Directory of Open Access Journals (Sweden)

    G.V. Pradeep Varma

    2015-03-01

    Full Text Available There is a more potential in a cement factory for electric power generation using waste heat recovery compared to the other industries. A case study has been done at a cement factory having two units, 1600 TPD and 5500 TPD, identified three waste heat rejections at 176 °C, 330 °C and 420 °C and designed a suitable power plant configuration. In this work, an attempt has been made to quantify the power generation capacity with plant analysis. It has been resulted that 12.5 MW of power can be produced with the available heat recovery against a cement factory demand of 15 MW. The available process heat for cement production and power generation has been estimated at a capacity range from 5000 to 9000 TPD. The analysis recommended a low steam pressure for power generation at above said heat recovery gas temperature.

  6. Direct waste heat recovery via thermoelectric materials - chosen issues of the thermodynamic description

    Science.gov (United States)

    Kolasiński, Piotr; Kolasińska, Ewa

    2016-02-01

    The effective waste heat recovery is one of the present-day challenges in the industry and power engineering. The energy systems dedicated for waste heat conversion into electricity are usually characterized by low efficiency and are complicated in the design. The possibility of waste heat recovery via thermoelectric materials may be an interesting alternative to the currently used technologies. In particular, due to their material characteristics, conducting polymers may be competitive when compared with the power machinery and equipment. These materials can be used in a wide range of the geometries e.g. the bulk products, thin films, pristine form or composites and the others. In this article, the authors present selected issues related to the mathematical and thermodynamic description of the heat transfer processes in the thermoelectric materials dedicated for the waste heat recovery. The link of these models with electrical properties of the material and a material solution based on a conducting polymer have also been presented in this paper.

  7. A methodology for the geometric design of heat recovery steam generators applying genetic algorithms

    International Nuclear Information System (INIS)

    This paper shows how the geometric design of heat recovery steam generators (HRSG) can be achieved. The method calculates the product of the overall heat transfer coefficient (U) by the area of the heat exchange surface (A) as a function of certain thermodynamic design parameters of the HRSG. A genetic algorithm is then applied to determine the best set of geometric parameters which comply with the desired UA product and, at the same time, result in a small heat exchange area and low pressure losses in the HRSG. In order to test this method, the design was applied to the HRSG of an existing plant and the results obtained were compared with the real exchange area of the steam generator. The findings show that the methodology is sound and offers reliable results even for complex HRSG designs. -- Highlights: ► The paper shows a methodology for the geometric design of heat recovery steam generators. ► Calculates product of the overall heat transfer coefficient by heat exchange area as a function of certain HRSG thermodynamic design parameters. ► It is a complement for the thermoeconomic optimization method. ► Genetic algorithms are used for solving the optimization problem

  8. Performance investigation of advanced adsorption desalination cycle with condenser-evaporator heat recovery scheme

    KAUST Repository

    Thu, Kyaw

    2013-01-01

    Energy or heat recovery schemes are keys for the performance improvement of any heat-activated cycles such as the absorption and adsorption cycles. We present two innovative heat recovery schemes between the condensing and evaporating units of an adsorption desalination (AD) cycle. By recovering the latent heat of condenser and dumping it into the evaporative process of the evaporator, it elevates the evaporating temperature and hence the adsorption pressure seen by the adsorbent. From isotherms, this has an effect of increasing the vapour uptake. In the proposed configurations, one approach is simply to have a run-about water circuit between the condenser and the evaporator and a pump is used to achieve the water circulation. This run-around circuit is a practical method for retrofitting purposes. The second method is targeted towards a new AD cycle where an encapsulated condenser-evaporator unit is employed. The heat transfer between the condensing and evaporative vapour is almost immediate and the processes occur in a fully integrated vessel, thereby minimizing the heat transfer resistances of heat exchangers. © 2013 Desalination Publications.

  9. Thermodynamic Analysis of a Ship Power Plant Operating with Waste Heat Recovery through Combined Heat and Power Production

    Directory of Open Access Journals (Sweden)

    Mirko Grljušić

    2014-11-01

    Full Text Available The goal of this research is to study a cogeneration plant for combined heat & power (CHP production that utilises the low-temperature waste energy in the power plant of a Suezmax-size oil tanker for all heating and electricity requirements during navigation. After considering various configurations, a standard propulsion engine operating at maximum efficiency and a CHP Plant with R245fa fluid using a supercritical organic Rankine cycle (ORC is selected. All the ship heat requirements can be covered by energy of organic fluid after expansion in the turbine, except feeder-booster heating. Hence, an additional quantity of working fluid may be heated using an after Heat Recovery Steam Generator (HRSG directed to the feeder-booster module. An analysis of the obtained results shows that the steam turbine plant does not yield significant fuel savings. However, a CHP plant with R245fa fluid using supercritical ORC meets all of the demands for electrical energy and heat while burning only a small amount of additional fuel in HRSG at the main engine off-design operation.

  10. Wind- and stack-assisted mechanical ventilation with heat recovery and night cooling

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    , a prototype of a heat exchanger, was developed based on design criteria about pressure drop, eciency and production concerns. The exchanger is based on banks of plastic tubing cris-crossing the air flow, thus creating approximate counter flow between air and water. Round PE plastic tubing is used. The tubing......The dual-sided issue of indoor environment and energy consumption have become increasingly important in building design. One possible solution is to ventilate by passive means, such as by stack eect and wind pressure, but this requires the development of new concepts and components. Here we have...... presented the outline of a heat recovery concept suitable for stack and wind-assisted mechanical ventilation systems with total system pressure losses of 74Pa. The heat recovery concept is based on two air-to-water exchangers connected by a liquid loop powered by a pump. The core element of the concept...

  11. Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources

    Science.gov (United States)

    Wajs, Jan; Mikielewicz, Dariusz; Fornalik-Wajs, Elżbieta; Bajor, Michał

    2015-12-01

    A tendency to increase the importance of so-called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative production of heat and electricity. For such systems the crucial points are connected with the heat exchangers, which should be small in size but be able to transfer high heat fluxes. In presented paper the prototype microjet heat exchanger dedicated for heat recovery systems is introduced. Its novel construction is described together with the systematical experimental analysis of heat transfer and flow characteristics. Reported results showed high values of the overall heat transfer coefficient and slight increase in the pressure drop. The results of microjet heat exchanger were compared with the results of commercially available compact plate heat exchanger.

  12. Heat Recovery in a Pasta Factory. Pinch Analysis Leads to Optimal Heat Pump Usage.

    OpenAIRE

    Staine, Frédéric; Favrat, Daniel; Krummenacher, Pierre

    1994-01-01

    In the previous issue of the IEA Heat Pump Centre Newsletter (Vol, 12, No.3, pp. 29-31), an article by these authors described the use of pinch analysis (also known as pinch technology) in a buildings application. This article describes a similar procedure for integrating a heat pump into a pasta production process. Many industrial processes, and particularly those dealing with drying, are characterized by an overabundance of low- grade heat which often cannot be effi...

  13. Advanced Energy and Water Recovery Technology from Low Grade Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Dexin Wang

    2011-12-19

    The project has developed a nanoporous membrane based water vapor separation technology that can be used for recovering energy and water from low-temperature industrial waste gas streams with high moisture contents. This kind of exhaust stream is widely present in many industrial processes including the forest products and paper industry, food industry, chemical industry, cement industry, metal industry, and petroleum industry. The technology can recover not only the sensible heat but also high-purity water along with its considerable latent heat. Waste heats from such streams are considered very difficult to recover by conventional technology because of poor heat transfer performance of heat-exchanger type equipment at low temperature and moisture-related corrosion issues. During the one-year Concept Definition stage of the project, the goal was to prove the concept and technology in the laboratory and identify any issues that need to be addressed in future development of this technology. In this project, computational modeling and simulation have been conducted to investigate the performance of a nanoporous material based technology, transport membrane condenser (TMC), for waste heat and water recovery from low grade industrial flue gases. A series of theoretical and computational analyses have provided insight and support in advanced TMC design and experiments. Experimental study revealed condensation and convection through the porous membrane bundle was greatly improved over an impermeable tube bundle, because of the membrane capillary condensation mechanism and the continuous evacuation of the condensate film or droplets through the membrane pores. Convection Nusselt number in flue gas side for the porous membrane tube bundle is 50% to 80% higher than those for the impermeable stainless steel tube bundle. The condensation rates for the porous membrane tube bundle also increase 60% to 80%. Parametric study for the porous membrane tube bundle heat transfer

  14. Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

    Directory of Open Access Journals (Sweden)

    Wail Aladayleh

    2015-01-01

    Full Text Available This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine.

  15. Ammonia and Carbon Dioxide Heat Pumps for Heat Recovery in Industry

    DEFF Research Database (Denmark)

    Brix, Wiebke; Christensen, Stefan W.; Markussen, Michael M.;

    2012-01-01

    . Calculations of cycle performances are performed using a reference cycle for both ammonia and carbon dioxide as refrigerant. For each cycle a thorough sensitivity analysis reveals that the forward and return temperatures of the heat sink (condenser or gas cooler) of the heat pump are most important for the...... coefficient of performance, COP. By comparing the cycles it is found that for each set of operating conditions the two refrigerants perform equally well at one given inlet temperature of the heat sink. Above this temperature ammonia cycles have the best COP and below CO2 cycles perform best. A general...... conclusion is that ammonia heat pumps are best at heat sink inlet temperatures above 28°C and CO2 is best below 24°C, independent of other parameters....

  16. Evaluation of trigeneration system using microturbine, ammonia-water absorption chiller, and a heat recovery boiler

    Energy Technology Data Exchange (ETDEWEB)

    Preter, Felipe C.; Rocha, Marcelo S.; Simoes-Moreira, Jose Roberto [SISEA - Alternative Energy Systems Lab. Dept. of Mechanical Engineering. University of Sao Paulo (EP/USP), SP (Brazil)], e-mails: felipe.preter@poli.usp.br, msrocha@poli.usp.br, jrsimoes@usp.br; Andreos, Ronaldo [COMGAS - Companhia de Gas de Sao Paulo, SP (Brazil)], e-mail: randreos@comgas.com.br

    2010-07-01

    In this work, a CCHP or tri generation system has been projected, mounted, and tested in laboratory, combining a microturbine for power generation, a heat recovery boiler for hot water production, and an ammonia water absorption chiller for chilled water production. The project was motivated by the large practical applications of this kind of energy recovery system in commerce, and industry, and, in general, more than 85% of the energy source is used as power, hot water, and cold water. In the first part, the trigeneration system theoretical model is detailed, and in the second part, experimental results are presented for different operation conditions. (author)

  17. ASPEN Plus simulation of coal integrated gasification combined blast furnace slag waste heat recovery system

    International Nuclear Information System (INIS)

    Highlights: • An integrated system of coal gasification with slag waste heat recovery was proposed. • The goal of BF slag heat saving and emission reduction was achieved by this system. • The optimal parameters were obtained and the waste heat recovery rate reached 83.08%. • About 6.64 kmol/min syngas was produced when using one ton BF slag to provide energy. - Abstract: This article presented a model for the system of coal gasification with steam and blast furnace slag waste heat recovery by using the ASPEN Plus as the simulating and modeling tool. Constrained by mass and energy balance for the entire system, the model included the gasifier used to product syngas at the chemical equilibrium based on the Gibbs free energy minimization approach and the boiler used to recover the heat of the blast furnace slag (BF slag) and syngas. Two parameters of temperature and steam to coal ratio (S/C) were considered to account for their impacts on the Datong coal (DT coal) gasification process. The carbon gasification efficiency (CE), cold gasification efficiency (CGE), syngas product efficiency (PE) and the heating value of syngas produced by 1 kg pulverized coal (HV) were adopted as the indicators to examine the gasification performance. The optimal operating temperature and S/C were 800 °C and 1.5, respectively. At this condition, CE reached above 90% and the maximum values of the CGE, PE and HV were all obtained. Under the optimal operating conditions, 1000 kg/min BF slag, about 40.41 kg/min DT pulverized coal and 77.94 kg/min steam were fed into the gasifier and approximate 6.64 kmol/min syngas could be generated. Overall, the coal was converted to clean syngas by gasification reaction and the BF slag waste heat was also recovered effectively (reached up to 83.08%) in this system, achieving the objective of energy saving and emission reduction

  18. Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tianqi He

    2016-04-01

    Full Text Available In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC, which are named the organic Rankine cycle (ORC, and heat pump (HP combined organic Rankine cycle (HPORC. The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60 °C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

  19. A study of trilateral flash cycles for low-grade waste heat recovery-to-power generation

    OpenAIRE

    Ajimotokan, Habeeb A.

    2014-01-01

    There has been renewed significance for innovative energy conversion technologies, particularly the heat recovery-to-power technologies for sustainable power generation from renewable energies and waste heat. This is due to the increasing concern over high demand for electricity, energy shortage, global warming and thermal pollution. Among the innovative heat recovery-to- power technologies, the proposed trilateral flash cycle (TFC) is a promising option, which presents a gr...

  20. Heating of domestic water by waste heat recovery from household refrigerating equipment

    Science.gov (United States)

    Reil, J.; Kaster, B.; Wegner, M.

    1982-09-01

    Heat from a 370 l deep freeze was used to heat water in a 250 l boiler. Both units were made from mass produced components. Tests show that the functions of cooling and deep freezing units can be effectively combined with one warm water boiler. The necessary expenditure for the appliance is, however, only economical with deep freezing units because with normal domestic refrigerators the amount of waste heat is too small. The economy of the unit could be considerably increased by the development of a mass produced motor compressor with a sufficiently large oil cooler to accomplish an optimum thermal insulation of the motor compressor surface area.

  1. Tritium recovery from helium purge stream of solid breeder blanket by cryogenic molecular sieve bed. 2. Regeneration operation of cryogenic molecular sieve bed

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Yoshinori; Enoeda, Mikio; Nishi, Masataka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Regeneration operation is a very important operation, because it is the most influential factor for deciding the net operation cycle time and the minimum dimension of Cryogenic Molecular Sieve Bed (CMSB). However, the experimental data of CMSB regeneration operation was not so sufficient that even the optimum regeneration procedure could not be decided yet. This work was focused on getting the primary information about various regeneration procedures. (author)

  2. Evaluation of Waste Heat Recovery and Utilization from Residential Appliances and Fixtures

    Energy Technology Data Exchange (ETDEWEB)

    Tomlinson, John J [ORNL; Christian, Jeff [Oak Ridge National Laboratory (ORNL); Gehl, Anthony C [ORNL

    2012-09-01

    Executive Summary In every home irrespective of its size, location, age, or efficiency, heat in the form of drainwater or dryer exhaust is wasted. Although from a waste stream, this energy has the potential for being captured, possibly stored, and then reused for preheating hot water or air thereby saving operating costs to the homeowner. In applications such as a shower and possibly a dryer, waste heat is produced at the same time as energy is used, so that a heat exchanger to capture the waste energy and return it to the supply is all that is needed. In other applications such as capturing the energy in drainwater from a tub, dishwasher, or washing machine, the availability of waste heat might not coincide with an immediate use for energy, and consequently a heat exchanger system with heat storage capacity (i.e. a regenerator) would be necessary. This study describes a two-house experimental evaluation of a system designed to capture waste heat from the shower, dishwasher clothes washer and dryer, and to use this waste heat to offset some of the hot water energy needs of the house. Although each house was unoccupied, they were fitted with equipment that would completely simulate the heat loads and behavior of human occupants including operating the appliances and fixtures on a demand schedule identical to Building American protocol (Hendron, 2009). The heat recovery system combined (1) a gravity-film heat exchanger (GFX) installed in a vertical section of drainline, (2) a heat exchanger for capturing dryer exhaust heat, (3) a preheat tank for storing the captured heat, and (4) a small recirculation pump and controls, so that the system could be operated anytime that waste heat from the shower, dishwasher, clothes washer and dryer, and in any combination was produced. The study found capturing energy from the dishwasher and clothes washer to be a challenge since those two appliances dump waste water over a short time interval. Controls based on the status of the

  3. WASTE HEAT RECOVERY FROM BOILER OF LARGE-SCALE TEXTILE INDUSTRY

    Directory of Open Access Journals (Sweden)

    Prateep Pattanapunt

    2013-01-01

    Full Text Available Many industrial heating processes generate waste energy in textile industry; especially exhaust gas from the boiler at the same time reducing global warming. Therefore, this article will present a study the way to recovery heat waste from boiler exhaust gas by mean of shell and tube heat exchanger. Exhaust gas from boiler dyeing process, which carries a large amount of heat, energy consumptions could be decrease by using of waste-heat recovery systems. In this study, using ANASYS simulation performs a thermodynamics analysis. An energy-based approach is performed for optimizing the effective working condition for waste-heat recovery with exhaust gas to air shell and tube heat exchanger. The variations of parameters, which affect the system performance such as, exhaust gas and air temperature, velocity and mass flow rate and moisture content is examined respectively. From this study, it was found that heat exchanger could be reduced temperature of exhaust gases and emission to atmosphere and the time payback is the fastest. The payback period was determined about 6 months for investigated ANSYS. The air is circulated in four passes from the top to the bottom of the test section, in overall counter-flow with exhaust gas. The front area is 1720×1720 mm, the flow length 7500 mm, the inner and outer diameter of exhaust gas is 800 mm, the tube assembly consist of 196 tubes, the tube diameter is 76.2 mm, the tube thickness is 2.6 mm, the tube length is 4500 mm, the tube length of air inner and outer is 500 mm. The result show that, the boiler for superheated type there are exhaust gas temperature is 190°C, 24% the moisture content of fuel and there are palm kernel shell 70 tons day-1 which there are the high temperature after the heat exchanger, 150°C. It was occurred acid rain. The hot air from heat exchanger process can be reduced the moisture of palm kernel shell fuel to 15%.The fuel consumption is reduced by about 2.05% (322.72 kJ kg-1

  4. A novel NGL (natural gas liquid) recovery process based on self-heat recuperation

    International Nuclear Information System (INIS)

    This study examined an innovative self-heat-recuperation technology that circulates latent and sensible heat in the thermal process and applied it to the NGL (natural gas liquid) recovery process. A CGCC (column grand composite curve) was used to assess the thermodynamic feasibility of implementing the heat pump system and self-heat-recuperation technology into a conventional distillation column. The proposed distillation based on self-heat recuperation reduced the energy consumption dramatically by compressing the effluent stream, whose temperature was increased to provide the minimum temperature difference for the heat exchanger, and circulating the stream heat in the process. According to a simulation of the proposed sequence, up to 73.43 and 83.48% of the condenser and reboiler energy, respectively, were saved compared to a conventional column. This study also proposes heat integration to improve the performance of self-heat recuperation. The results showed that the modified sequence saves up 64.35, 100.00 and 31.60% of the condenser energy requirements, reboiler energy requirements and OP (operating cost), respectively, compared to a classical heat pump system, and 90.24, 100.00, and 67.19%, respectively, compared to a conventional column. The use of these sequences to retrofit a distillation column to save energy was also considered. - Highlights: • Innovative self-heat-recuperation technology that circulates latent and sensible heat. • A CGCC (column grand composite curve) is used to assess the thermodynamic feasibility. • The proposed sequence saves up 67.19% of the OP (operating cost). • The proposed sequences can be used to retrofit a distillation column to save energy

  5. Application of waste heat powered absorption refrigeration system to the LNG recovery process

    Energy Technology Data Exchange (ETDEWEB)

    Kalinowski, Paul; Hwang, Yunho; Radermacher, Reinhard [Center for Environmental Energy Engineering, Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 (United States); Al Hashimi, Saleh; Rodgers, Peter [The Petroleum Institute, Abu Dhabi (United Arab Emirates)

    2009-06-15

    The recovery process of the liquefied natural gas requires low temperature cooling, which is typically provided by the vapor compression refrigeration systems. The usage of an absorption refrigeration system powered by waste heat from the electric power generating gas turbine could provide the necessary cooling at reduced overall energy consumption. In this study, a potential replacement of propane chillers with absorption refrigeration systems was theoretically analyzed. From the analysis, it was found that recovering waste heat from a 9 megawatts (MW) electricity generation process could provide 5.2 MW waste heat produced additional cooling to the LNG plant and save 1.9 MW of electricity consumption. Application of the integrated cooling, heating, and power is an excellent energy saving option for the oil and gas industry. (author)

  6. Selection criteria for plain and segmented finned tubes for heat recovery systems

    Science.gov (United States)

    Reid, D. R.; Taborek, J.

    1994-04-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded 'plain' fins were generally used in the past, until the high-frequency resistance welding technology permitted a cost-effective manufacture of 'segmented' fins. The main advantage of this fin design is that it permits higher heat flux and hence smaller, lighter weight units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight, and cost per unit area favor the segmented fin design, a few other considerations such as fouling, ease of cleaning, and availability of dependable design methods have to be considered. This paper analyzes the performance parameters that affect the selection of either fin type.

  7. Recovery of exhaust waste heat for a hybrid car using steam turbine

    Science.gov (United States)

    Ababatin, Yasser

    A number of car engines operate with an efficiency rate of approximately 22% to 25% [1]. The remainder of the energy these engines generate is wasted through heat escape out of the exhaust pipe. There is now an increasing desire to reuse this heat energy, which would improve the overall efficiency of car engines by reducing their consumption of fuel. Another benefit is that such reuse would minimize harmful greenhouse gases that are emitted into the environment. Therefore, the purpose of this project is to examine how the wasted heat energy can be reused and/or recovered by use of a heat recovery system that would store this energy in a hybrid car battery. Green turbines will be analyzed as a possible solution to recycle the lost energy in a way that will also improve the overall automotive energy efficiency.

  8. Waste Heat Recovery from the Advanced Test Reactor Secondary Coolant Loop

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen

    2012-11-01

    This study investigated the feasibility of using a waste heat recovery system (WHRS) to recover heat from the Advanced Test Reactor (ATR) secondary coolant system (SCS). This heat would be used to preheat air for space heating of the reactor building, thus reducing energy consumption, carbon footprint, and energy costs. Currently, the waste heat from the reactor is rejected to the atmosphere via a four-cell, induced-draft cooling tower. Potential energy and cost savings are 929 kW and $285K/yr. The WHRS would extract a tertiary coolant stream from the SCS loop and pump it to a new plate and frame heat exchanger, from which the heat would be transferred to a glycol loop for preheating outdoor air supplied to the heating and ventilation system. The use of glycol was proposed to avoid the freezing issues that plagued and ultimately caused the failure of a WHRS installed at the ATR in the 1980s. This study assessed the potential installation of a new WHRS for technical, logistical, and economic feasibility.

  9. Oxidative stress impairs the heat stress response and delays unfolded protein recovery.

    Directory of Open Access Journals (Sweden)

    Masaaki Adachi

    Full Text Available BACKGROUND: Environmental changes, air pollution and ozone depletion are increasing oxidative stress, and global warming threatens health by heat stress. We now face a high risk of simultaneous exposure to heat and oxidative stress. However, there have been few studies investigating their combined adverse effects on cell viability. PRINCIPAL FINDINGS: Pretreatment of hydrogen peroxide (H(2O(2 specifically and highly sensitized cells to heat stress, and enhanced loss of mitochondrial membrane potential. H(2O(2 exposure impaired the HSP40/HSP70 induction as heat shock response (HSR and the unfolded protein recovery, and enhanced eIF2alpha phosphorylation and/or XBP1 splicing, land marks of ER stress. These H(2O(2-mediated effects mimicked enhanced heat sensitivity in HSF1 knockdown or knockout cells. Importantly, thermal preconditioning blocked H(2O(2-mediated inhibitory effects on refolding activity and rescued HSF1 +/+ MEFs, but neither blocked the effects nor rescued HSF1 -/- MEFs. These data strongly suggest that inhibition of HSR and refolding activity is crucial for H(2O(2-mediated enhanced heat sensitivity. CONCLUSIONS: H(2O(2 blocks HSR and refolding activity under heat stress, thereby leading to insufficient quality control and enhancing ER stress. These uncontrolled stress responses may enhance cell death. Our data thus highlight oxidative stress as a crucial factor affecting heat tolerance.

  10. Draft report: application of organic Rankine cycle heat recovery systems to diesel powered marine vessels

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-15

    The analysis and results of an investigation of the application of organic Rankine cycle heat recovery systems to diesel-powered marine vessels are described. The program under which this study was conducted was sponsored jointly by the US Energy Research and Development Administration, the US Navy, and the US Maritime Administration. The overall objective of this study was to investigate diesel bottoming energy recovery systems, currently under development by three US concerns, to determine the potential for application to marine diesel propulsion and auxiliary systems. The study primarily focused on identifying the most promising vessel applications (considering vessel type, size, population density, operational duty cycle, etc.) so the relative economic and fuel conservation merits of energy recovery systems could be determined and assessed. Vessels in the current fleet and the projected 1985 fleet rated at 1000 BHP class and above were investigated.

  11. Engineering Scoping Study of Thermoelectric Generator Systems for Industrial Waste Heat Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, Terry [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choate, William T. [BCS, Inc., Laurel, MD (United States)

    2006-11-01

    This report evaluates thermoelectric generator (TEG) systems with the intent to: 1) examine industrial processes in order to identify and quantify industrial waste heat sources that could potentially use TEGs; 2) describe the operating environment that a TEG would encounter in selected industrial processes and quantify the anticipated TEG system performance; 3) identify cost, design and/or engineering performance requirements that will be needed for TEGs to operate in the selected industrial processes; and 4) identify the research, development and deployment needed to overcome the limitations that discourage the development and use of TEGs for recovery of industrial waste heat.

  12. Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part II: Parametric Evaluation and Topological Studies

    Science.gov (United States)

    Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.; Meisner, Gregory P.

    2013-06-01

    A comprehensive numerical model has been proposed to model thermoelectric generators (TEGs) for automotive waste heat recovery. Details of the model and results from the analysis of General Motors' prototype TEG were described in part I of the study. In part II of this study, parametric evaluations are considered to assess the influence of heat exchanger, geometry, and thermoelectric module configurations to achieve optimization of the baseline model. The computational tool is also adapted to model other topologies such as transverse and circular configurations (hexagonal and cylindrical) maintaining the same volume as the baseline TEG. Performance analysis of these different topologies and parameters is presented and compared with the baseline design.

  13. Fuel cell heat recovery, electrical load management, and the economics of solar-hydrogen systems

    Energy Technology Data Exchange (ETDEWEB)

    Shabani, B.; Andrews, J. [Royal Melbourne Inst. of Technology, Melbourne, VIC (Australia). School of Aerospace, Mechanical and Manufacturing Engineering; Badwal, S.P.S. [Australian Commonwealth Scientific and Research Organization CSIRO Energy Transformed Flagship and Energy Technology, Clayton South (Australia)

    2009-03-11

    A solar-hydrogen system located in a remote household in southeast Australia was modelled in order to investigate electrical load management and fuel cell heat recovery processes. An electrical demand profile was used to determine factors related to power supply system size. Results of the study showed that the operating cost of the solar-hydrogen system can be reduced by managing peak demands while ensuring that the average daily electrical energy supply remains constant. Increases in fuel cell size lowered the average unit cost of energy due to the fact that larger fuel cells operate at lower current densities. Although recoverable heat supplies are lowered when optimal load management practices are applied, a net economic benefit for both heat and power is observed. The economic gains of recovering heat for domestic hot water were estimated at approximately US$4300 over an assessment period of 30 years. The economic gains of combining the load management technique with the heat recovery process were estimated at US$8164 over the same time period. 19 refs., 2 tabs., 8 figs.

  14. Exergy efficiency enhancement of MSF desalination by heat recovery from hot distillate water stages

    International Nuclear Information System (INIS)

    This detailed exergy analysis of a 3800 m3/h Multi-Stage Flash (MSF) desalination plant is based on the latest published thermodynamics properties of water and seawater. The parameters of the study were extracted from a validated model of MSF desalination using IPSEpro software. The results confirmed that the overall exergy efficiency of the unit is lower than would be desirable at only 5.8%. Exergy inputs were destroyed by 55%, 17%, 10%, 4.3%, and 14% respectively, in the heat recovery stages, brine heater, heat rejection stages, pumps and brine streams disposal. Moreover, the detail of the study showed that the lowest exergy destruction occurs in the first stage, increasing gradually in heat recovery stages and sharply in heat rejection stages. The study concludes that recovering the heat from the hot distillate water stages can improve unit exergy efficiency from its low 5.8% to a more economical 14%, with the hot water parameters suitable for powering other thermal systems such as absorption chiller and multi-effect desalination

  15. Calculation of Efficiencies of a Ship Power Plant Operating with Waste Heat Recovery through Combined Heat and Power Production

    Directory of Open Access Journals (Sweden)

    Mirko Grljušić

    2015-05-01

    Full Text Available The aim of this research was to investigate the possibility of a combined heat & power (CHP plant, using the waste heat from a Suezmax-size oil tanker’s main engine, to meet all heating and electricity requirements during navigation. After considering various configurations, a standard propulsion engine operating at maximum efficiency, combined with a supercritical Organic Rankine cycle (ORC system, was selected to supply the auxiliary power, using R245fa or R123 as the working fluid. The system analysis showed that such a plant can meet all heat and electrical power requirements at full load, with the need to burn only a small amount of supplementary fuel in a heat recovery steam generator (HRSG when the main engine operates at part load. Therefore, it is possible to increase the overall thermal efficiency of the ship’s power plant by more than 5% when the main engine operates at 65% or more of its specified maximum continuous rating (SMCR.

  16. Performance of Counter Flow Heat Recovery Ventilation Systems in Dwellings Considering the Influence of Uncertainties

    OpenAIRE

    Yang, Z.; Cauberg, J.J.M.; Tenpierik, M.J.

    2012-01-01

    Both critical and optimistic claims have been made regarding the performance of heat recovery ventilation systems (HRVS) in dwellings. Such arguments are raised partly because two key aspects are not fully clarified, i.e. the performance criteria and the influence of uncertainties. In the current paper, an assessment method for HRVS considering the influence of uncertainties is described. This includes adequate assessment criteria, the method of identifying the uncertainties, and the method o...

  17. Inverse Estimation of Temperature Profiles in Landfills Using Heat Recovery Fluids Measurements

    OpenAIRE

    V. G. Dovi'; Reverberi, A.P.; A. Del Borghi; C. Solisio

    2012-01-01

    In addition to leachate and gas emission analysis, temperature variations in municipal solid waste landfills are routinely monitored for safety and health reasons, such as the increased production of biogas or the danger of spontaneous combustion phenomena if the temperature exceeds 70–75°C. The increasing constraints on greenhouse gas emissions and the convenience of fuel and heat recovery have helped develop a global approach to landfills' operation and maintenance, generally referred to as...

  18. Integrated energy and emission management for diesel engines with waste heat recovery using dynamic models

    OpenAIRE

    Willems Frank; Kupper Frank; Rascanu George; Feru Emanuel

    2015-01-01

    Rankine-cycle Waste Heat Recovery (WHR) systems are promising solutions to reduce fuel consumption for trucks. Due to coupling between engine and WHR system, control of these complex systems is challenging. This study presents an integrated energy and emission management strategy for an Euro-VI Diesel engine with WHR system. This Integrated Powertrain Control (IPC) strategy optimizes the CO2-NOx trade-off by minimizing online the operational costs associated with fuel and AdBlue consumption. ...

  19. Thermodynamic analysis of an in-cylinder waste heat recovery system for internal combustion engines

    International Nuclear Information System (INIS)

    In this paper, an in-cylinder waste heat recovery system especially for turbocharged engines is proposed to improve the thermal efficiencies of internal combustion engines. Simplified recovery processes can be described as follows: superheated steam generated by engine waste heat is injected into the pipe before the turbine to increase the boost pressure of the fresh air; intake valve close timing is adjusted to control the amount of fresh air as the original level, and thus the higher pressure charged air expands in the intake stroke and transfers the pressure energy directly to the crankshaft. In this way, the increased turbine output by the pre-turbine steam injection is finally recovered in the cylinder, which is different from the traditional Rankine cycle. The whole energy transfer processes are studied with thermodynamic analyses and numerical simulations. The results show that the mass flow rate of the injected steam has the biggest influence on the energy transfer processes followed by the temperature of the injected steam. With this in-cylinder waste heat recovery system, the fuel economy of a selected turbocharged diesel engine can be improved by 3.2% at the rated operating point when the injected mass flow ratio is set to be 0.1. - Highlights: • An in-cylinder waste heat recovery system is proposed. • Effects of injected parameters are studied with energy and exergy balance theories. • Variations of operating points on the compressor map are studied in detail. • The fuel economy is improved by 3.2% at the rated operating point

  20. A combined thermodynamic cycle based on methanol dissociation for IC (internal combustion) engine exhaust heat recovery

    International Nuclear Information System (INIS)

    In this paper, a novel approach for exhaust heat recovery was proposed to improve IC (internal combustion) engine fuel efficiency and also to achieve the goal for direct usage of methanol as IC engine fuel. An open organic Rankine cycle system using methanol as working medium is coupled to IC engine exhaust pipe for exhaust heat recovery. In the bottom cycle, the working medium first undergoes dissociation and expansion processes, and is then directed back to IC engine as fuel. As the external bottom cycle and the IC engine main cycle are combined together, this scheme forms a combined thermodynamic cycle. Then, this concept was applied to a turbocharged engine, and the corresponding simulation models were built for both of the external bottom cycle and the IC engine main cycle. On this basis, the energy saving potential of this combined cycle was estimated by parametric analyses. Compared to the methanol vapor engine, IC engine in-cylinder efficiency has an increase of 1.4–2.1 percentage points under full load conditions, while the external bottom cycle can increase the fuel efficiency by 3.9–5.2 percentage points at the working pressure of 30 bar. The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points. - Highlights: • A combined thermodynamic cycle using methanol as working medium for IC engine exhaust heat recovery is proposed. • The external bottom cycle of exhaust heat recovery and IC engine working cycle are combined together. • IC engine fuel efficiency could be improved from both in-cylinder working cycle and external bottom cycle. • The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points at full load

  1. Thermoelectric Exhaust Heat Recovery with Heat Pipe-Based Thermal Control

    Science.gov (United States)

    Brito, F. P.; Martins, Jorge; Hançer, Esra; Antunes, Nuno; Gonçalves, L. M.

    2015-06-01

    Heat pipe (HP)-based heat exchangers can be used for very low resistance heat transfer between a hot and a cold source. Their operating temperature depends solely on the boiling point of their working fluid, so it is possible to control the heat transfer temperature if the pressure of the HP can be adjusted. This is the case of the variable conductance HPs (VCHP). This solution makes VCHPs ideal for the passive control of thermoelectric generator (TEG) temperature levels. The present work assesses, both theoretically and experimentally, the merit of the aforementioned approach. A thermal and electrical model of a TEG with VCHP assist is proposed. Experimental results obtained with a proof of concept prototype attached to a small single-cylinder engine are presented and used to validate the model. It was found that the HP heat exchanger indeed enables the TEG to operate at a constant, optimal temperature in a passive and safe way, and with a minimal overall thermal resistance, under part load, it effectively reduces the active module area without deprecating the temperature level of the active modules.

  2. Numerical study of finned type heat exchangers for ICEs exhaust waste heat recovery

    Directory of Open Access Journals (Sweden)

    M. Hatami

    2014-11-01

    Full Text Available In this paper, two cases of heat exchangers (HEXs which previously were used in exhaust of internal combustion engines (ICEs are modeled numerically to recover the exhaust waste heat. It is tried to find the best viscous model to obtain the results with more accordance by experimental results. One of the HEXs is used in a compression ignition (CI engine with water as cold fluid and other is used in a spark ignition (SI engine with a mixture of 50% water and 50% ethylene glycol as cold fluid. As a main outcome, SST k–ω and RNG k–ε are suitable viscous models for these kinds of problems. Also, effect sizes and numbers of fins on recovered heat amount are investigated in various engine loads and speeds.

  3. Experimental study of a burner with high temperature heat recovery system for TPV applications

    International Nuclear Information System (INIS)

    An experimental investigation to develop and test a burner and a heat recovery system for thermophotovoltaic (TPV) applications is presented. Experimental data have been compared with theoretical calculations and considerations in the pre-design and design phases of the project to find the weakest point of the concept and to validate the expected performance. The TPV generator has been designed as a compact module in order to be used as a range extender in an electric car. The heat recovery system is the key element to increase the efficiency of the system. The heat recovery system presented in this paper is a rotary type regenerator that is very compact and has higher effectiveness in comparison with other types of regenerators with the same number of transfer units (NTU). The experimental data have been used to verify the numerical models used in the calculations for design of the regenerator matrix. A new version of the numerical model has been developed to take into account the variation of the thermal properties of the system with the temperature. Dimensions, weight, efficiency, emissions and high working temperatures have been the most important competitive constraints to observe for design of the system

  4. Minimum variance control of organic Rankine cycle based waste heat recovery

    International Nuclear Information System (INIS)

    Highlights: • The self-tuning generalized minimum variance control is applied for a waste heat recovery process with organic Rankine cycle. • The design procedure of generalized minimum variance controller is presented. • Simulation tests show the tracking ability and the disturbance rejecting performance of this controller. - Abstract: In this paper, an online self-tuning generalized minimum variance (GMV) controller is proposed for a 100 KW waste heat recovery system with organic Rankine cycle (ORC). The ORC process model is formulated by the controlled autoregressive moving average (CARMA) model whose parameters are identified using the recursive least squares (RLS) algorithm with forgetting factor. The generalized minimum variance algorithm is applied to regulate ORC based waste heat recovery system. The contributions of this work are twofold: (1) the proposed control strategy is formulated under the data-driven framework, which does not need the precise mathematic model; (2) this proposed method is applied to handle tracking set-point variations and process disturbances by improved minimum objective GMV function. The performance of GMV controller is compared with the PID controller. The simulation results show that the proposed strategy can achieve satisfactory set-point tracking and disturbance rejection performance

  5. A combined air cycle used for IC engine supercharging based on waste heat recovery

    International Nuclear Information System (INIS)

    Highlights: • A combined air cycle is proposed for IC engine supercharging based on WHR. • Cycle efficiency and energy recovery efficiency depend largely on working pressure. • Exhaust gas pressure of IC engine with combined air cycle is reduced largely. • IC engine fuel efficiency can be increased by 4.1% points at most. - Abstract: A combined air cycle is designed for internal combustion (IC) engine supercharging, which consists of IC engine working cycle and bottom cycle of waste heat recovery (WHR). The bottom cycle uses IC engine exhaust gas as cycle heat source, and its output power is used to drive the gas compressor. Both the heat transfer and thermodynamic processes of combined air cycle were investigated by numerical calculation under various cycle parameters and IC engine operating conditions. On this basis, the performances of combined air cycle and the improvement to IC engine performances were analyzed. Results show that, the cycle efficiency and exhaust gas energy recovery efficiency depend largely on the working pressure, and their maximum values appear at the working pressure of 0.35 MPa and 0.2 MPa, respectively. Compared with the naturally aspirated (NA) engine and turbocharging engine, this approach can make the fuel utilization efficiency of IC engine increase by 8.9% points and 4.1% points at most, respectively, due to the reduction of exhaust gas pressure. All these demonstrate that the proposed concept is a potentially useful approach for IC engine energy saving

  6. Energy and exergy analyses of a bottoming Rankine cycle for engine exhaust heat recovery

    International Nuclear Information System (INIS)

    In this paper, a theoretical study on the thermodynamic processes of a bottoming Rankine cycle for engine waste heat recovery is conducted from the viewpoints of energy balance and exergy balance. A theoretical formula and an exergy distribution map for qualitative analyses of the main operating parameters are presented under simplified conditions when exhaust gas is selected as the only heat source. Five typical working fluids, which are always selected by manufacturers for different types of engines, are compared under various operating conditions in Matlab software. The results show that working fluid properties, evaporating pressure and superheating temperature are the main factors influencing the system design and performances. The global recovery efficiency does not exceed 0.14 under typical operating conditions. Ethanol and R113 show better thermodynamic performances in the whole exhaust gas temperature range. In addition, the optimal evaporating pressure usually does not exist in engine exhaust heat recovery, and the distributions of exergy destruction are varied with working fluid categories and system design constraints. - Highlights: • A theoretical formula for qualitative analyses of the Rankine cycle is proposed. • System exergy destruction is investigated with an exergy distribution map. • Design constraints of the bottoming Rankine cycle for ICEs are summarized. • The optimal evaporating pressure does not occur under typical exhaust conditions. • The exergy destruction depends on working fluid categories and system constraints

  7. Kinetics of recovery and recystallization of the large heat of V-4Cr-4Ti

    Energy Technology Data Exchange (ETDEWEB)

    Gubbi, A N; Rowcliffe, A F; Eatherly, W S; Gibson, L T

    1996-04-01

    A series of slow cycle and rapid cycle anneals was carried out in the large heat of V-4Cr-4Ti alloy (heat 832665). Also, a differential scanning calorimetry (DSC) study was initiated on the samples of the same alloy. The recovery and recrystallization phenomena of V-4Cr-4Ti in slow cycle annealing were quite different from that observed in rapid cycle annealing. The large driving force for recrystallization due to rapid heating resulted in the first nuclei appearing after only 1 minute of 1000{degrees}C. There was a two-stage hardness reduction; the first stage involved recovery due to cell formation and annihilation of dislocation, and second stage was associated with the growth of recrystallization nuclei. This is consistent with results obtained from the DSC in which there was a broad exothermic peak from {approx}200 to 800{degrees}C due to recovery followed by a sharp exotherm associated with recrystallization. The activation energy for recrystallization for V-4Cr-4Ti, which was determined at 576 {+-} 75, kJ/mole is significantly higher than that for pure V, and is thought to be related to Ti and Cr in solid solution.

  8. Modelling of waste heat recovery for combined heat and power applications

    International Nuclear Information System (INIS)

    The current environmental context dictates to reduce the pollutant emissions by improving thermal efficiency of the energy production units. The authors present some studies of cogeneration applications using gas turbines and thermal engines. The on-going research concerns a detailed study of thermodynamic modelling cycles with energy recovery. These combined cycles with gas turbine and ICE can generate a potential increase of about 10% of the energy efficiency. They will generate a technological complexity and the over-charge must be estimated. At last, the authors insist on the necessary synergy between gas turbines and thermal engines.

  9. Heat recovery from Diesel engines: A thermodynamic comparison between Kalina and ORC cycles

    International Nuclear Information System (INIS)

    In the context of heat recovery for electric power generation, Kalina cycle (a thermodynamic cycle using as working fluid a mixture of water and ammonia) and Organic Rankine Cycle (ORC) represent two different eligible technologies. In this work a comparison between the thermodynamic performances of Kalina cycle and an ORC cycle, using hexamethyldisiloxane as working fluid, was conducted for the case of heat recovery from two Diesel engines, each one with an electrical power of 8900 kWe. The maximum net electric power that can be produced exploiting the heat source constituted by the exhaust gases mass flow (35 kg/s for both engines, at 346 deg. C) was calculated for the two thermodynamic cycles. Owing to the relatively low useful power, for the Kalina cycle a relatively simple plant layout was assumed. Supposing reasonable design parameters and a logarithmic mean temperature difference in the heat recovery exchanger of 50 deg. C, a net electric power of 1615 kW and of 1603 kW respectively for the Kalina and for the ORC cycle was calculated. Although the obtained useful powers are actually equal in value, the Kalina cycle requires a very high maximum pressure in order to obtain high thermodynamic performances (in our case, 100 bar against about 10 bar for the ORC cycle). So, the adoption of Kalina cycle, at least for low power level and medium-high temperature thermal sources, seems not to be justified because the gain in performance with respect to a properly optimized ORC is very small and must be obtained with a complicated plant scheme, large surface heat exchangers and particular high pressure resistant and no-corrosion materials.

  10. Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling and Baseline Model Analysis

    Science.gov (United States)

    Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.; Meisner, Gregory P.

    2013-04-01

    A numerical model has been developed to simulate coupled thermal and electrical energy transfer processes in a thermoelectric generator (TEG) designed for automotive waste heat recovery systems. This model is capable of computing the overall heat transferred, the electrical power output, and the associated pressure drop for given inlet conditions of the exhaust gas and the available TEG volume. Multiple-filled skutterudites and conventional bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from exhaust into usable electrical power. Heat transfer between the hot exhaust gas and the hot side of the TEMs is enhanced with the use of a plate-fin heat exchanger integrated within the TEG and using liquid coolant on the cold side. The TEG is discretized along the exhaust flow direction using a finite-volume method. Each control volume is modeled as a thermal resistance network which consists of integrated submodels including a heat exchanger and a thermoelectric device. The pressure drop along the TEG is calculated using standard pressure loss correlations and viscous drag models. The model is validated to preserve global energy balances and is applied to analyze a prototype TEG with data provided by General Motors. Detailed results are provided for local and global heat transfer and electric power generation. In the companion paper, the model is then applied to consider various TEG topologies using skutterudite and bismuth telluride TEMs.

  11. Numerical Modeling of Fin and Tube Heat Exchanger for Waste Heat Recovery

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    In the present work, multiphysics numerical modeling is carried out to predict the performance of a liquid-gas fin and tube heat exchanger design. Three-dimensional (3D) steady-state numerical model using commercial software COMSOL based on finite element method (FEM) is developed. The study...

  12. Parkhotel Bellevue, Adelboden - Measurement campaign on heat recovery; Parkhotel Bellevue Adelboden. Schlussbericht der Messkampagne der WRG Wellness-Anlage

    Energy Technology Data Exchange (ETDEWEB)

    Grob, D. [Grob und Schoepfer AG, Wil (Switzerland); Baumann, E. [Baumann Akustik und Bauphysik AG, Bazenheid (Switzerland)

    2004-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a measurement campaign carried out on the heat-recovery system of a spa and wellness complex installed at the Park Hotel Bellevue in Adelboden, Switzerland, in 2001. The report takes a look at how heat is recovered from wastewater from the baths, showers and the filter-backwash water of the hotels' salt-water pool. The heat recovered is used to pre-heat the hot-water supply and the brine supply for the salt-water pool. Schematics, photos and tables present details of the installations. The results of the measurements made are presented and discussed. The percentage of energy needs met by the heat-recovery system is quoted and discussed. The economic feasibility of the project is also examined. Suggestions for further heat-recovery action to be taken are made.

  13. Modelling of Evaporator in Waste Heat Recovery System using Finite Volume Method and Fuzzy Technique

    Directory of Open Access Journals (Sweden)

    Jahedul Islam Chowdhury

    2015-12-01

    Full Text Available The evaporator is an important component in the Organic Rankine Cycle (ORC-based Waste Heat Recovery (WHR system since the effective heat transfer of this device reflects on the efficiency of the system. When the WHR system operates under supercritical conditions, the heat transfer mechanism in the evaporator is unpredictable due to the change of thermo-physical properties of the fluid with temperature. Although the conventional finite volume model can successfully capture those changes in the evaporator of the WHR process, the computation time for this method is high. To reduce the computation time, this paper develops a new fuzzy based evaporator model and compares its performance with the finite volume method. The results show that the fuzzy technique can be applied to predict the output of the supercritical evaporator in the waste heat recovery system and can significantly reduce the required computation time. The proposed model, therefore, has the potential to be used in real time control applications.

  14. Review of organic Rankine cycles for internal combustion engine exhaust waste heat recovery

    International Nuclear Information System (INIS)

    Escalating fuel prices and future carbon dioxide emission limits are creating a renewed interest in methods to increase the thermal efficiency of engines beyond the limit of in-cylinder techniques. One promising mechanism that accomplishes both objectives is the conversion of engine waste heat to a more useful form of energy, either mechanical or electrical. This paper reviews the history of internal combustion engine exhaust waste heat recovery focusing on Organic Rankine Cycles since this thermodynamic cycle works well with the medium-grade energy of the exhaust. Selection of the cycle expander and working fluid are the primary focus of the review, since they are regarded as having the largest impact on system performance. Results demonstrate a potential fuel economy improvement around 10% with modern refrigerants and advancements in expander technology. -- Highlights: ► This review article focuses on engine exhaust waste heat recovery works. ► The organic Rankine cycle is superior for low to medium exergy heat sources. ► Working fluid and expander selection strongly influence efficiency. ► Several authors demonstrate viable systems for vehicle installation

  15. Energy aAnalysis and Kinetics of Mint Leaves Dehydration Using Vibro-Fluidized Bed Heat Pump Dryer

    Directory of Open Access Journals (Sweden)

    S. M Ataei Ardestani

    2016-04-01

    Full Text Available Fluidized bed dryers have not yet been used for drying products such as mint leaves. This could be due to high porosity and low mechanical resistance resulting in poor quality of fluidization. Applying vibration has been recommended to overcome problems such as channeling and defluidization, and hence improving the fluidization quality. In this research, a laboratory scale vibro-fluidized bed heat pump dryer was designed and constructed for drying mint leaves. The experiments were conducted at vibration frequency of 80 Hz and amplitude of 3 mm. The velocity and temperature of the inlet air was controlled by an automatic control system. Experiments were carried out at 40, 50 and 60 °C, and two methods: heat pump drying (HPD and non-heat pump drying (NHPD. The results revealed that drying process primarily occurred in the falling rate period. Effective moisture diffusivity of the samples increased with increase in drying air temperature and varied from 4.26656×10-11 to 2.95872×10-10 m2 s-1 for the HPD method, and 3.71918×10-11 to 1.29196×10-10 m2 s-1 for the NHPD method and was within the reported range of 10-9 to 10-11 m2 s-1 for drying of food materials. The activation energy was determined to be 84 kJ mol-1 for the HPD and 54.34 kJ mol-1 for the NHPD, both have very good agreement with the results of other investigators. The coefficient of performance and specific moisture evaporation rate showed the acceptable performance of the heat pump system. Moreover, the energy consumption of the dryer for the NHPD method was more than the HPD method.

  16. New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Ming [Purdue University, West Lafayette, IN; Abdelaziz, Omar [ORNL; Yin, Hongxi [Southeast University, Nanjing, China

    2014-11-01

    Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150 200 C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50 60 C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural gas boilers for applications with process fluid return temperatures higher than or close to the dew point of the water vapor in the flue gas.

  17. Thermo-economic analysis of steady state waste heat recovery in data centers using absorption refrigeration

    International Nuclear Information System (INIS)

    Highlights: • Absorption refrigeration is powered by data center waste heat. • Waste heat from 3 to 5 server racks produces cooling for an additional rack. • An economic analysis shows the payback period can be as short as 4–5 months. - Abstract: This paper addresses the technical and economic issues associated with waste heat recovery in data centers through the use of absorption cooling machines. The theoretical possibility of utilizing the heat dissipated by a server, or a number of servers, to power an absorption system, which in turn produces cooling for other servers in the data center, is investigated. For this purpose, a steady-state thermodynamic model is developed to perform energy balance and exergy analyses for a novel configuration of an on-chip two-phase cooling system and an absorption refrigeration system. This combination is created by replacing the condenser in the on-chip cooling circuit with the generator of an absorption refrigeration cycle. The performance of the developed model in simulating both LiBr–water and water–ammonia absorption cooling systems is examined through verification of the model results against the reference data available in the literature. The verification indicates the superiority of LiBr–water absorption system for data center/server operating conditions. Therefore, a LiBr–water absorption refrigeration system is modeled in the novel combined heat recovery system. For these systems it is shown that the traditional definition for the coefficient of performance (COP) is not appropriate to evaluate the performance and, in its place, introduce a new figure of merit. Through a sensitivity analysis, the effects of server waste heat quality, server coolant type, solution peak concentration, solution heat exchanger effectiveness, evaporator temperature, and operating pressures on the performance of the novel system are investigated. Finally, using the thermodynamic model and cost information provided by the

  18. Influence of thermophoresis on particle removal in a moving granular bed filter and heat exchanger

    International Nuclear Information System (INIS)

    Bench-scale investigations were made to determine the influence of thermophoresis on particle removal in a moving granular bed filter. A continuous flow of 2-mm diameter ceramic granules at ambient temperature entered the top of the filter and moved slowly downward under the influence of gravity countercurrent to the gas stream. At an inlet gas temperature of 2400C, gas mass velocity of 0.12 kg/(s.m2), and granule velocities up to 0.015 cm/s, clean bed collection efficiency for a submicrometer sodium chloride aerosol was found to increase the more the gas was cooled, indicating that thermophoretic forces were playing a measurable role in particle collection

  19. Use of a turboexpander in steam power units for heat energy recovery in heat supply systems

    Science.gov (United States)

    Sadykov, R. A.; Daminov, A. Z.; Solomin, I. N.; Futin, V. A.

    2016-05-01

    A method for raising the efficiency of a boiler plant by installing a unit operating by the organic Rankine cycle is presented. Such units allow one to generate electricity to cover the auxiliaries of a heat source at a heat-transfer fluid temperature of no more than 130°C. The results of commissioning tests of boilers revealed that their efficiency is maximized under a load that is close or corresponds to the nominal one. If this load is maintained constantly, excess heat energy is produced. This excess may be used to generate electric energy in a steam power unit with a turboexpander. A way to insert this unit into the flow diagram of a boiler plant is proposed. The results of analysis of turbine types (turboexpanders included) with various capacities are presented, and the optimum type for the proposed flow diagram is chosen. The methodology for the design of turboexpanders and compressors used in the oil and gas industry and their operational data were applied in the analysis of a turboexpander. The results of the thermogasdynamic analysis of a turboexpander and the engineered shape of an axial-radial impeller are presented. Halocarbon R245fa is chosen as the working medium based on its calorimetric properties.

  20. Thermodynamic evaluation of the Kalina split-cycle concepts for waste heat recovery applications

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Knudsen, Thomas; Larsen, Ulrik;

    2014-01-01

    The Kalina split-cycle is a thermodynamic process for converting thermal energy into electrical power. It uses an ammonia–water mixture as a working fluid (like a conventional Kalina cycle) and has a varying ammonia concentration during the pre-heating and evaporation steps. This second feature...... results in an improved match between the heat source and working fluid temperature profiles, decreasing the entropy generation in the heat recovery system. The present work compares the thermodynamic performance of this power cycle with the conventional Kalina process, and investigates the impact...... cycle with reheat, and by 4.3% points without reheat. The cycle efficiency varies by 14% points for a variation of the exhaust gas temperature of 100 °C, and by 1% point for a cold water temperature variation of 30 °C. This analysis also pinpoints the large irreversibilities in the low-pressure turbine...

  1. Optimization of a thermoelectric generator subsystem for high temperature PEM fuel cell exhaust heat recovery

    DEFF Research Database (Denmark)

    Gao, Xin; Andreasen, Søren Juhl; Kær, Søren Knudsen;

    2014-01-01

    In previous work, a thermoelectric (TE) exhaust heat recovery subsystem for a high temperature polymer electrolyte membrane (HT-PEM) fuel cell stack was developed and modeled. Numerical simulations were conducted and have identified an optimized subsystem configuration and 4 types of compact heat...... exchangers with superior performance for further analysis. In this work, the on-design performances of the 4 heat exchangers are more thoroughly assessed on their corresponding optimized subsystem configurations. Afterward, their off-design performances are compared on the whole working range of the fuel...... cell stack. All through this study, different electrical connection styles of all the thermoelectric generator (TEG) modules in the subsystem and their influences are also discussed. In the end, the subsystem configuration is further optimized and a higher subsystem power output is achieved. All TEG...

  2. Optimization of Boiler Blowdown and Blowdown Heat Recovery in Textile Sector

    Directory of Open Access Journals (Sweden)

    Sunudas T

    2013-09-01

    Full Text Available Boilers are widely used in most of the processing industries like textile, for the heating applications. Surat is the one of the largest textile processing area in India. In textile industries coal is mainly used for the steam generation. In a textile industry normally a 4% of heat energy is wasted through blowdown. In the study conducted in steam boilers in textile industries in surat location, 1.5% of coal of total coal consumption is wasted in an industry by improper blowdwon. This thesis work aims to prevent the wastage in the coal use by optimizing the blowdown in the boiler and maximizing the recovery of heat wasting through blowdown.

  3. Study and Design of Waste Heat Recovery using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Seyed Saied Homami

    2016-03-01

    Full Text Available Existing energy crisis in the world has diverted human perspective to the optimum usage of the available energy resources. One of these solutions is waste heat recovery systems[1]. Simultaneous production of fresh water, power and cooling from waste heat improves energy efficiency in industrial applications which could be operated by organic Rankine cycles. In this article, cogeneration of electricity and heat (CHP in the petrochemical industry, textile and paper production has been reviewed and the usage of aforesaid cycle in these industries is determined. Designing organic Rankine cycle (with operating fluid organic trans-butene and taking advantage of the excess low pressure steam, a strategy for producing three valuable products of fresh water, power and refrigeration in the petrochemical industries has been offered. Simultaneous production of 10,000 kg/hr fresh water, 1533 kw power and access to the lower temperatures of about 226 K and 260 K were resulted.

  4. Recovery of Heat Treated Bacillus cereus Spores Is Affected by Matrix Composition and Factors with Putative Functions in Damage Repair.

    Science.gov (United States)

    Warda, Alicja K; Tempelaars, Marcel H; Abee, Tjakko; Nierop Groot, Masja N

    2016-01-01

    The ability of spores to recover and grow out after food processing is affected by cellular factors and by the outgrowth conditions. In the current communication we studied the recovery and outgrowth of individually sorted spores in BHI and rice broth media and on agar plates using flow cytometry. We show that recovery of wet heat treated Bacillus cereus ATCC 14579 spores is affected by matrix composition with highest recovery in BHI broth or on rice agar plates, compared to BHI agar plates and rice broth. Data show that not only media composition but also its liquid or solid state affect the recovery of heat treated spores. To determine the impact of factors with putative roles in recovery of heat treated spores, specific genes previously shown to be highly expressed in outgrowing heat-treated spores were selected for mutant construction. Spores of nine B. cereus ATCC 14579 deletion mutants were obtained and their recovery from wet heat treatment was evaluated using BHI and rice broth and agar plates. Deletion mutant spores showed different capacity to recover from heat treatment compared to wild type with the most pronounced effect for a mutant lacking BC5242, a gene encoding a membrane protein with C2C2 zinc finger which resulted in over 95% reduction in recovery compared to the wild type in BHI broth. Notably, similar relative performance of wild type and mutants was observed using the other recovery conditions. We obtained insights on the impact of matrix composition and state on recovery of individually sorted heat treated spores and identified cellular factors with putative roles in this process. These results may provide leads for future developments in design of more efficient combined preservation treatments. PMID:27486443

  5. Case study : Syncrude Canada Ltd. optimizing waste heat recovery at an oil sands operation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Syncrude Canada Ltd., the world's largest producer of crude oil from oil sands, has made upgrades over a seven-year period to its water recycling process, resulting in more heat recovered at the preheaters in its oil sands operations. The preheaters are the key to the recycling process water system. The incentive to optimize heat recovery at the preheaters was to reduce the amount of natural gas required to heat the water used to extract bitumen from the oil sands. The second objective was to lower costs spent on new equipment to heat the water. Syncrude operators attended workshops offered by the Office of Energy Efficiency at Natural Resources Canada to learn the value of monitoring and cleaning the process-water system to recover as much lost heat as possible. This paper presented a project profile and the approach used to optimize the system, beginning with the installation of twisted-tube heat exchangers in 1997, followed by the installation of a larger pump impeller in 1998 which increased the pumping capacity. In 2003, the target outlet temperature for the preheaters was set at 20 degrees C. This paper also described the challenges regarding water temperature, water pressure and maintenance issues. The innovative solutions used to overcome them have lead to energy costs savings of about $60,000 per month. Syncrude is currently exploring whether water can be preheated higher than 20 degrees C. 2 figs.

  6. Exergy analysis of the Szewalski cycle with a waste heat recovery system

    Directory of Open Access Journals (Sweden)

    Kowalczyk Tomasz

    2015-09-01

    Full Text Available The conversion of a waste heat energy to electricity is now becoming one of the key points to improve the energy efficiency in a process engineering. However, large losses of a low-temperature thermal energy are also present in power engineering. One of such sources of waste heat in power plants are exhaust gases at the outlet of boilers. Through usage of a waste heat regeneration system it is possible to attain a heat rate of approximately 200 MWth, under about 90 °C, for a supercritical power block of 900 MWel fuelled by a lignite. In the article, we propose to use the waste heat to improve thermal efficiency of the Szewalski binary vapour cycle. The Szewalski binary vapour cycle provides steam as the working fluid in a high temperature part of the cycle, while another fluid – organic working fluid – as the working substance substituting conventional steam over the temperature range represented by the low pressure steam expansion. In order to define in detail the efficiency of energy conversion at various stages of the proposed cycle the exergy analysis was performed. The steam cycle for reference conditions, the Szewalski binary vapour cycle as well as the Szewalski hierarchic vapour cycle cooperating with a system of waste heat recovery have been comprised.

  7. Exergy analysis of the Szewalski cycle with a waste heat recovery system

    Science.gov (United States)

    Kowalczyk, Tomasz; Ziółkowski, Paweł; Badur, Janusz

    2015-09-01

    The conversion of a waste heat energy to electricity is now becoming one of the key points to improve the energy efficiency in a process engineering. However, large losses of a low-temperature thermal energy are also present in power engineering. One of such sources of waste heat in power plants are exhaust gases at the outlet of boilers. Through usage of a waste heat regeneration system it is possible to attain a heat rate of approximately 200 MWth, under about 90 °C, for a supercritical power block of 900 MWel fuelled by a lignite. In the article, we propose to use the waste heat to improve thermal efficiency of the Szewalski binary vapour cycle. The Szewalski binary vapour cycle provides steam as the working fluid in a high temperature part of the cycle, while another fluid - organic working fluid - as the working substance substituting conventional steam over the temperature range represented by the low pressure steam expansion. In order to define in detail the efficiency of energy conversion at various stages of the proposed cycle the exergy analysis was performed. The steam cycle for reference conditions, the Szewalski binary vapour cycle as well as the Szewalski hierarchic vapour cycle cooperating with a system of waste heat recovery have been comprised.

  8. Studies on the effect of ohmic heating on oil recovery and quality of sesame seeds.

    Science.gov (United States)

    Kumari, Kirti; Mudgal, V D; Viswasrao, Gajanan; Srivastava, Himani

    2016-04-01

    This research describes a new technological process for sesame oil extraction. The process deals with the effect of ohmic heating on enhancement of oil recovery and quality of cleaned and graded sesame seed. The effect of ohmic heating parameters namely electric field strength (EFS), end point temperature (EPT) and holding time (HT) on oil extraction process were investigated. Three levels of electric field strength (600, 750 and 900 V/m), end point temperature (65, 75 and 85 °C) and holding time (5, 10 and 15 min.) were taken as independent variables using full factorial design. Percentage oil recovered from sesame seed through mechanical extracted oil by application of ohmic heating varies from 39.98 to 43.15 %. The maximum oil recovery 43.15 % was obtained when the sample was heated and maintained at 85 °C using EFS of 900 V/m for a holding time of 10 min as against 34.14 % in control sample. The free fatty acid (FFA) of the extracted oil was within the acceptable limit (1.52 to 2.26 % oleic acid) of 0.5 to 3 % as prescribed respectively by Prevention of Food Adulteration (PFA) and Bureau of Indian Standards (BIS). The peroxide value of extracted oil was also found within the acceptable limit (0.78 to 1.01 meq/kg). The optimum value for maximum oil recovery, minimum residual oil content, free fatty acid (FFA) and peroxide value were 41.24 %, 8.61 %, 1.74 % oleic acid and 0.86 meq/kg, respectively at 722.52 V/m EFS at EPT 65 °C for 5 min. holding time which was obtained by response surface methodology. PMID:27413228

  9. Analysis of vehicle exhaust waste heat recovery potential using a Rankine cycle

    International Nuclear Information System (INIS)

    This study evaluates the vehicle exhaust WHR (waste heat recovery) potential using a RC (Rankine cycle ). To this end, both a RC thermodynamic model and a heat exchanger model have been developed. Both models use as input, experimental data obtained from a vehicle tested on a chassis dynamometer. The thermodynamic analysis was performed for water, R123 and R245fa and revealed the advantage of using water as the working fluid in applications of thermal recovery from exhaust gases of vehicles equipped with a spark-ignition engine. Moreover, the heat exchanger effectiveness for the organic working fluids R123 and R245fa is higher than that for the water and, consequently, they can also be considered appropriate for use in vehicle WHR applications through RCs when the exhaust gas temperatures are relatively low. For an ideal heat exchanger, the simulations revealed increases in the internal combustion engine thermal and vehicle mechanical efficiencies of 1.4%–3.52% and 10.16%–15.95%, respectively, while for a shell and tube heat exchanger, the simulations showed an increase of 0.85%–1.2% in the thermal efficiency and an increase of 2.64%–6.96% in the mechanical efficiency for an evaporating pressure of 2 MPa. The results confirm the advantages of using the thermal energy contained in the vehicle exhaust gases through RCs. Furthermore, the present analysis demonstrates that improved evaporator designs and appropriate expander devices allowing for higher evaporating pressures are required to obtain the maximum WHR potential from vehicle RC systems. -- Highlights: ► This study evaluates the vehicle exhaust waste heat recovery potential using Rankine cycle systems. ► A thermodynamic model and a heat exchanger model were developed. ► Experimental data obtained in a vehicle tested on a chassis dynamometer was used as models input. ► Thermodynamic analysis was performed for water, R123 and R245fa. ► Results confirm advantages of using the thermal energy

  10. Unidimensional heat transfer analysis of elephant grass and sugar cane bagasse slow pyrolysis in a fixed bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mesa-Perez, J.M.; Cortez, L.A.B. [Faculdade de Engenharia Agricola-FEAGRI/UNICAMP, Cidade Universitaria ' Zeferino Vaz' , Barao Geraldo, CP 6011, 13084-971, Campinas SP (Brazil); Rocha, J.D.; Olivares-Gomez, E. [Nucleo Interdisciplinar de Planejamento Energetico, NIPE/UNICAMP, Cidade Universitaria ' Zeferino Vaz' , Barao Geraldo, CP 6086, 13084-971, Campinas SP (Brazil); Brossard-Perez, L.E. [Faculdad de Ingenieria Quimica, Universidade de Oriente Sede Mella, ave, Las Americas sn, Ampliacion de Terraza, Santiago de Cuba, CP 90 600 (Cuba)

    2005-02-25

    Elephant grass (Pennicetum purpureum) and sugar cane bagasse slow pyrolysis experiments was carried out in a fixed bed reactor. A 20-cm internal diameter and 12-cm-long reactor was used. Particulate biomass filled up the reactor volume. Biomass was loaded into the reactor and heated in the axial direction using an electrical resistance located at the reactor's bottom. In order to control the temperature variation during the biomass pyrolysis process, four thermocouples were installed inside of the reactor. The remain residual mass was constant approximately after 73 min of heating; the running was stopped and remain carbonised; material was manually removed from the reactor. The residue formed three layer of biomass visually different described in detail here. Proximate analysis and higher heating value (HHV) tests were carried out to the material in each layer. Mass loss against time was recorded during experiments. The results indicated that the carbonisation ratio decreases in time because the carbon layer has low thermal conductivity and it does not permit proper heat transfer to the upper layer of biomass. It means that technology that avoids high-temperature gradients during the pyrolysis of bulk-dispersed biomass could avoid the problems described before.

  11. Direct in situ butanol recovery inside the packed bed during continuous acetone-butanol-ethanol (ABE) fermentation.

    Science.gov (United States)

    Wang, Yin-Rong; Chiang, Yu-Sheng; Chuang, Po-Jen; Chao, Yun-Peng; Li, Si-Yu

    2016-09-01

    In this study, the integrated in situ extraction-gas stripping process was coupled with continuous ABE fermentation using immobilized Clostridium acetobutylicum. At the same time, oleyl alcohol was cocurrently flowed into the packed bed reactor with the fresh medium and then recycled back to the packed bed reactor after removing butanol in the stripper. A high glucose consumption of 52 g/L and a high butanol productivity of 11 g/L/h were achieved, resulting in a high butanol yield of 0.21 g-butanol/g-glucose. This can be attributed to both the high bacterial activity for solvent production as well as a threefold increase in the bacterial density inside the packed bed reactor. Also reported is that 64 % of the butanol produced can be recovered by the integrated in situ extraction-gas stripping process. A high butanol productivity and a high glucose consumption were simultaneously achieved. PMID:27005413

  12. Trends in heat recovery in modern Dutch supermarkets; Trends in WTW bij moderne Nederlandse supermarkten

    Energy Technology Data Exchange (ETDEWEB)

    Jans, R. [Coolsultancy, Breda (Netherlands)

    2012-06-15

    The signing of the energy efficiency covenant by a large number of supermarkets has made the deployment of heat recovery in refrigeration quite common. Previous reports have mentioned the importance of aligning the various disciplines. Generally, the heat installer is unaware of the influence he has on the energy use of refrigeration. This article addresses several types of heat recovery that may be suitable for deployment, depending on the situation (new buildings, renovation, et cetera) [Dutch] Doordat een groot aantal supermarkten het convenant energiebesparing bij supermarkten hebben ondertekend is het toepassen van WTW op de koel- en vriesinstallatie nagenoeg gemeen goed geworden. In eerdere rapportages is reeds melding gemaakt van het belang van de afstemming tussen de verschillende disciplines. Over het algemeen kan gezegd worden dat de warmte-installateur zich niet bewust is welke invloed hij uitoefent op het energiegebruik van de koel- en vriesinstallatie. In dit artikel komen een aantal uitvoeringsvormen van WTW aan de orde die op dit moment afhankelijk van de situatie (nieuwbouw/renovatie, enz.) overwogen kunnen worden.

  13. Waste burning and heat recovery characteristics of a mass burn incineration system.

    Science.gov (United States)

    Chen, Wei-Hsin

    2003-02-01

    An experimental investigation on waste combustion characteristics of a mass burn incinerator is conducted in this study. Three different charging modes, including operator manipulation, periodic feeding, and temperature control, are taken into consideration. The results indicate that the burning characteristics in the combustion chambers are closely related to the operating modes. For the operator manipulation where the wastes are sent into the incinerator in two short periods, the entire temperature distribution of the primary combustion chamber can be partitioned into two parts, thereby yielding waste group combustion. Temperature oscillations in both the primary and secondary combustion chambers are characterized for the periodic feeding. However, because of the shorter charging period and smaller amount of waste, the burning interaction between the two chambers is initially weak and becomes notable in the final stage. When temperature control is performed, the burning oscillation of the primary combustion chamber is further amplified so the combustion interaction is drastic. These exhibitions are mainly caused by the competition between endothermic and exothermic reactions. The instantaneous heat exchange efficiency of the cyclone heat recovery system (CHRS) installed in the incineration system is also evaluated to obtain details of energy recovery behaviors. As a result, the efficiency tends to decrease linearly with increasing temperature of hot flue gas. This arises from the fact that heat loss from the gas to the environment is increased when the temperature of the former is higher, even though the temperature gradient across the cyclone is enlarged. PMID:12617288

  14. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W.

    1996-06-01

    The objective of the research is to provide databases and design criteria to assist in the selection of optimum alloys for construction of components needed to contain process streams in advanced heat recovery and hot-gas cleanup systems. Typical components include: steam line piping and superheater tubing for low emission boilers (600 to 700{degrees}C), heat exchanger tubing for advanced steam cycles and topping cycle systems (650 to 800{degrees}C), foil materials for recuperators, on advanced turbine systems (700 to 750{degrees}C), and tubesheets for barrier filters, liners for piping, cyclones, and blowback system tubing for hot-gas cleanup systems (850 to 1000{degrees}C). The materials being examined fall into several classes, depending on which of the advanced heat recovery concepts is of concern. These classes include martensitic steels for service to 650{degrees}C, lean stainless steels and modified 25Cr-30Ni steels for service to 700{degrees}C, modified 25Cr-20Ni steels for service to 900{degrees}C, and high Ni-Cr-Fe or Ni-Cr-Co-Fe alloys for service to 1000{degrees}C.

  15. Disposal of High-Temperature Slags: A Review of Integration of Heat Recovery and Material Recycling

    Science.gov (United States)

    Sun, Yongqi; Zhang, Zuotai

    2016-05-01

    Nowadays with the continuous urbanization in China, the carbon emission and resource shortage have been serious issues, for which the disposal of blast furnace slags (BFS) and steel slags (SS) discharged from the metallurgical industry make up a significant strategy. The output of crude steel reached 823 Mt in China in 2014 and the thermal heat in these slags was equivalent to ~18 Mt of standard coal. Herein, the recent advances were systemically reviewed and analyzed, mainly from two respects, i.e., integration of heat recovery and material recycling and crystallization control of the slags. It was first found that for the heat recovery from BFS, the most intensively investigated physical method and chemical method were centrifugal granulation and gasification reaction, respectively. Furthermore, a two-step approach could contribute to a promising strategy for the treatment of slags, i.e., the liquid slags were first granulated into small particles, and then other further treatment was performed such as gasification reaction. With regard to SS, the effective disposal could be achieved using a selective crystallization and phase separation (SCPS) method, and moreover, the solid solution of 2CaO·SiO2 and the target phases could act as a promising enriched phase to extract the valuable elements.

  16. Second law analysis of a diesel engine waste heat recovery with a combined sensible and latent heat storage system

    International Nuclear Information System (INIS)

    The exhaust gas from an internal combustion engine carries away about 30% of the heat of combustion. The energy available in the exit stream of many energy conversion devices goes as waste. The major technical constraint that prevents successful implementation of waste heat recovery is due to intermittent and time mismatched demand for and availability of energy. The present work deals with the use of exergy as an efficient tool to measure the quantity and quality of energy extracted from a diesel engine and stored in a combined sensible and latent heat storage system. This analysis is utilized to identify the sources of losses in useful energy within the components of the system considered, and provides a more realistic and meaningful assessment than the conventional energy analysis. The energy and exergy balance for the overall system is quantified and illustrated using energy and exergy flow diagrams. In order to study the discharge process in a thermal storage system, an illustrative example with two different cases is considered and analyzed, to quantify the destruction of exergy associated with the discharging process. The need for promoting exergy analysis through policy decision in the context of energy and environment crisis is also emphasized. - Highlights: → WHR with TES system eliminates the mismatch between the supply of energy and demand. → A saving of 15.2% of energy and 1.6% of exergy is achieved with PCM storage. → Use of multiple PCMs with cascaded system increases energy and exergy efficiency.

  17. Second law analysis of a diesel engine waste heat recovery with a combined sensible and latent heat storage system

    Energy Technology Data Exchange (ETDEWEB)

    Pandiyarajan, V., E-mail: pandiyarajan_v@yahoo.com [Institute for Energy Studies, Anna University, Chennai-600 025 (India); Chinnappandian, M., E-mail: muthuchinnapandian@yahoo.com [Department of Mechanical Engineering, St. Peter' s Engineering College, Avadi, Chennai-600054 (India); Raghavan, V., E-mail: raghavan.energy@gmail.com [Institute for Energy Studies, Anna University, Chennai-600 025 (India); Velraj, R., E-mail: velrajr@gmail.com [Institute for Energy Studies, Anna University, Chennai-600 025 (India)

    2011-10-15

    The exhaust gas from an internal combustion engine carries away about 30% of the heat of combustion. The energy available in the exit stream of many energy conversion devices goes as waste. The major technical constraint that prevents successful implementation of waste heat recovery is due to intermittent and time mismatched demand for and availability of energy. The present work deals with the use of exergy as an efficient tool to measure the quantity and quality of energy extracted from a diesel engine and stored in a combined sensible and latent heat storage system. This analysis is utilized to identify the sources of losses in useful energy within the components of the system considered, and provides a more realistic and meaningful assessment than the conventional energy analysis. The energy and exergy balance for the overall system is quantified and illustrated using energy and exergy flow diagrams. In order to study the discharge process in a thermal storage system, an illustrative example with two different cases is considered and analyzed, to quantify the destruction of exergy associated with the discharging process. The need for promoting exergy analysis through policy decision in the context of energy and environment crisis is also emphasized. - Highlights: > WHR with TES system eliminates the mismatch between the supply of energy and demand. > A saving of 15.2% of energy and 1.6% of exergy is achieved with PCM storage. > Use of multiple PCMs with cascaded system increases energy and exergy efficiency.

  18. Simulation of CO2 Brayton Cycle for Engine Exhaust Heat Recovery under Various Operating Loads

    Institute of Scientific and Technical Information of China (English)

    舒歌群; 张承宇; 田华; 高媛媛; 李团兵; 仇荣赓

    2015-01-01

    A bottoming cycle system based on CO2 Brayton cycle is proposed to recover the engine exhaust heat. Its performance is compared with the conventional air Brayton cycle under five typical engine conditions. The results show that CO2 Brayton cycle proves to be superior to the air Brayton cycle in terms of the system net output power, thermal efficiency and recovery efficiency. In most cases, the recovery efficiency of CO2 Brayton cycle can be higher than 9%and the system has a better performance at the engine’s high operating load. The thermal efficiency can be as large as 24.83%under 100%operating load, accordingly, the net output power of 14.86 kW is obtained.

  19. Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs

    OpenAIRE

    Rukke, Bjørn Arne; Aak, Anders; Edgar, Kristin Skarsfjord

    2015-01-01

    Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40...

  20. The pebble bed high temperature reactor as a source of nuclear process heat. Vol. 2

    International Nuclear Information System (INIS)

    A theoretical analysis is given for a series of 8 different variants of the pebble-bed reactor in the 'once through' fuel management scheme. The comparison gives some insight into the parametric sensitivities and into the development potential of this type. The thorium/U-233 recycling fuel cycle allows to increase the conversion ratio up to the range between 0.90 and 0.95. The feasibility for a changeover between different fuel cycles under full power operation. - The study is complemented by a review of the relevant previous investigations. (orig.)

  1. A thermodynamic analysis of waste heat recovery from reciprocating engine power plants by means of Organic Rankine Cycles

    International Nuclear Information System (INIS)

    Organic Rankine Cycle (ORC) is a Rankine cycle using organic fluid as the working fluid instead of water and steam. The ORC process is a feasible choice in waste heat recovery applications producing electricity from relatively low-temperature waste heat sources or in applications having a rather low power output. Utilizing waste heat from a large high-efficiency reciprocating engine power plant with ORC processes is studied by means of computations. In addition to exhaust gas heat recovery, this study represents and discusses an idea of directly replacing the charge air cooler (CAC) of a large turbocharged engine with an ORC evaporator to utilize the charge air heat in additional power production. A thermodynamic analysis for ORCs was carried out with working fluids toluene, n-pentane, R245fa and cyclohexane. The effect of different ORC process parameters on the process performance are presented and analyzed in order to investigate the heat recovery potential from the exhaust gas and charge air. A simplified feasibility consideration is included by comparing the ratio of the theoretical heat transfer areas needed and the obtained power output from ORC processes. The greatest potential is related to the exhaust gas heat recovery, but in addition also the lower temperature waste heat streams could be utilized to boost the electrical power of the engine power plant. A case study for a large-scale gas-fired engine was carried out showing that the maximum power increase of 11.4% was obtained from the exhaust gas and 2.4% from the charge air heat. - Highlights: • Waste heat recovery potential of reciprocating engines was studied. • Thermodynamic optimization for ORCs was carried out with different fluids. • The utilization of exhaust gas and charge air heat is presented and discussed. • Simplified economic feasibility study was included in the analysis. • Power increase of 11.4% was obtained from exhaust gas and 2.4% from charge air

  2. Heat recovery investigation from dryer–thermal oxidizer system in corn-ethanol plants

    International Nuclear Information System (INIS)

    In recent years, annual corn ethanol production in the U.S. has exceeded 13,298,000,000 gallons. However, net energy balance for this sector became a subject of controversy in many discussions. The aim of the presented research is an investigation of thermal improvement opportunities in a corn ethanol plant. For this purpose, a complex mathematical model was developed for a dryer–thermal oxidizer system. Three variants were subjected thermodynamic analyses: one state of the art system and two proposed system modifications. The properties of humid gas, a mixture of combustion products and moisture evaporated from distiller's grain, were updated based on the steam properties according to the formulation proposed by the International Association for the Properties of Water and Steam. All calculations were performed by uniquely-developed C++ code. The results indicate major potential for improvement in the following areas: (i) water recovery from humid gas; (ii) heat recovery from moisture condensation – max. 44% of total primary energy usage (TPEU); and (iii) fuel savings by reduction of humid gas flow through a thermal oxidizer – max. 1.4% of TPEU. Also the presented analysis can be a starting point for further modifications in real corn ethanol manufacturing applications, leading towards pilot system implementation. - Highlights: • Mathematical model for dryer–oxidizer system in a corn ethanol plant was proposed. • Three configurations were discussed: with intercooler, regenerator, and recuperator. • Recovery rate of water condensed at various conditions and locations was quantified. • Heat recovery possibilities at various temperatures and locations have been assessed. • Energy savings in thermal oxidizer due to preliminary condensation were calculated

  3. Effect of Internal Heat Recovery in Ammonia-Water Absorption Cooling Cycles: Exergy and Structural Analysis

    Directory of Open Access Journals (Sweden)

    Miquel Nogués

    2009-03-01

    Full Text Available First and second law analysis have been conducted for three low temperature driven ammonia-water absorption cooling cycles with increasing internal heat recovery. Based on the results of exergy analysis the structural analysis has been achieved. The obtained Coefficients of Structural Bonds (CSB consider how the irreversibility of the whole cycle is affected by a change in the irreversibility related to an efficiency improvement of a single component. Trends for the different configurations are similar, while quantitative differences among the main heat exchangers are considerable. The highest values of the CSB are found for the refrigerant heat exchanger. Also the evaporator, the condenser, the generator and the absorber show values higher than unity. The lowest CSB’s are obtained in the solution heat exchanger. In general, CSB’s decrease with increasing efficiency. That means that for very efficient heat exchangers, a further improvement looks less attractive. The dephlegmator is an exception as it shows a singularity of the CSB value due to its complex interactions with the other components. Once the CSB’s are obtained for the main components, they can be used in the structural method of the thermoeconomic optimisation. This method enables us to find the optimum design of a component in a straightforward calculation.

  4. Heat recovery steam generators design considerations addressing utility combined cycle needs

    International Nuclear Information System (INIS)

    The application of large gas turbines to combined cycles for power production has increased significantly in the past ten years. Heat Recovery Steam Generators for large power plant applications have been developed to meet utility customer needs for compressed delivery and installation schedules, compliance with present and future emissions requirements, dispatchability, ruggedness and maintainability. This paper discusses design features of the current generation of HRSGs that promote modular shop assembly, minimum field erection, and characteristics that provide the ability to perform in quick start-up and daily cycle service

  5. Energy savings in industrial NH/sub 3/ plant by heat recovery in the waste heat system

    Energy Technology Data Exchange (ETDEWEB)

    Weber, H.; Graeve, H.W.; Herbort, H.J.; Marsch, H.D.

    1984-05-01

    Minimization of energy consumption is nowadays a primary goal in the design of NH/sub 3/ plant. In this context two aspects are particularly important: first, the process steps and their combination must be selected in such a way that the level of energy that has to be supplied to the plant is kept low from the very beginning; second, heat recovery must be optimized by the choice of process conditions and use of appropriate equipment. An industrial NH/sub 3/ plant built according to these principles can operate at a consumption of as low as 29.5 GJ/t NH/sub 3/, using proven processes and equipment. The first plant of this new generation with a capacity of 1120 t/d is currently under construction for Canadian Industries Ltd. (CIL) in Canada.

  6. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Edward; Bilirgen, Harun; DuPont, John

    2011-03-31

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: • An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing highmoisture, low rank coals. • Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. • Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. • Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. • Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. • Condensed flue gas water treatment needs and costs. • Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. • Results of cost-benefit studies of condensing heat exchangers.

  7. Recovery of Water from Boiler Flue Gas Using Condensing Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy; Harun Bilirgen; John DuPoint

    2011-03-31

    Most of the water used in a thermoelectric power plant is used for cooling, and DOE has been focusing on possible techniques to reduce the amount of fresh water needed for cooling. DOE has also been placing emphasis on recovery of usable water from sources not generally considered, such as mine water, water produced from oil and gas extraction, and water contained in boiler flue gas. This report deals with development of condensing heat exchanger technology for recovering moisture from flue gas from coal-fired power plants. The report describes: (1) An expanded data base on water and acid condensation characteristics of condensing heat exchangers in coal-fired units. This data base was generated by performing slip stream tests at a power plant with high sulfur bituminous coal and a wet FGD scrubber and at a power plant firing high-moisture, low rank coals. (2) Data on typical concentrations of HCl, HNO{sub 3} and H{sub 2}SO{sub 4} in low temperature condensed flue gas moisture, and mercury capture efficiencies as functions of process conditions in power plant field tests. (3) Theoretical predictions for sulfuric acid concentrations on tube surfaces at temperatures above the water vapor dewpoint temperature and below the sulfuric acid dew point temperature. (4) Data on corrosion rates of candidate heat exchanger tube materials for the different regions of the heat exchanger system as functions of acid concentration and temperature. (5) Data on effectiveness of acid traps in reducing sulfuric acid concentrations in a heat exchanger tube bundle. (6) Condensed flue gas water treatment needs and costs. (7) Condensing heat exchanger designs and installed capital costs for full-scale applications, both for installation immediately downstream of an ESP or baghouse and for installation downstream of a wet SO{sub 2} scrubber. (8) Results of cost-benefit studies of condensing heat exchangers.

  8. The Misselhorn Cycle: Batch-Evaporation Process for Efficient Low-Temperature Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Moritz Gleinser

    2016-05-01

    Full Text Available The concept of the Misselhorn cycle is introduced as a power cycle that aims for efficient waste heat recovery of temperature sources below 100 °C. The basic idea shows advantages over a standard Organic Rankine Cycle (ORC in overall efficiency and utilization of the heat source. The main characteristic of this cycle is the use of at least three parallel batch evaporators instead of continuous heat exchangers. The operational phases of the evaporators are shifted so that there is always one vaporizer in discharge mode. A transient MATLAB® model (The MathWorks: Natick, MA, USA is used to simulate the achievable performance of the Misselhorn cycle. The calculations of the thermodynamic states of the system are based on the heat flux, the equations for energy conservation and the equations of state found in the NIST Standard Reference Database 23 (Reference Fluid Thermodynamic and Transport Properties - REFPROP, National Institute of Standards and Technology: Gaithersburg, MD, USA. In the isochoric batch evaporation, the pressure and the corresponding boiling temperature rise over time. With a gradually increasing boiling temperature, no pinch point limitation occurs. Furthermore, the heat source medium is passed through the evaporators in serial order to obtain a quasi-counter flow setup. It could be shown that these features offer the possibility to gain both high thermal efficiencies and an enhanced utilization of the heat source at the same time. A basic model with a fixed estimated heat transfer coefficient promises a possible system exergy efficiency of 44.4%, which is an increase of over 60% compared to a basic ORC with a system exergy efficiency of only 26.8%.

  9. Reuse of Produced Water from CO2 Enhanced Oil Recovery, Coal-Bed Methane, and Mine Pool Water by Coal-Based Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, Chad [Univ. of Illinois, Champaign, IL (United States); Dastgheib, Seyed A. [Univ. of Illinois, Champaign, IL (United States); Yang, Yaning [Univ. of Illinois, Champaign, IL (United States); Ashraf, Ali [Univ. of Illinois, Champaign, IL (United States); Duckworth, Cole [Univ. of Illinois, Champaign, IL (United States); Sinata, Priscilla [Univ. of Illinois, Champaign, IL (United States); Sugiyono, Ivan [Univ. of Illinois, Champaign, IL (United States); Shannon, Mark A. [Univ. of Illinois, Champaign, IL (United States); Werth, Charles J. [Univ. of Illinois, Champaign, IL (United States)

    2012-07-01

    Power generation in the Illinois Basin is expected to increase by as much as 30% by the year 2030, and this would increase the cooling water consumption in the region by approximately 40%. This project investigated the potential use of produced water from CO2 enhanced oil recovery (CO2-EOR) operations; coal-bed methane (CBM) recovery; and active and abandoned underground coal mines for power plant cooling in the Illinois Basin. Specific objectives of this project were: (1) to characterize the quantity, quality, and geographic distribution of produced water in the Illinois Basin; (2) to evaluate treatment options so that produced water may be used beneficially at power plants; and (3) to perform a techno-economic analysis of the treatment and transportation of produced water to thermoelectric power plants in the Illinois Basin. Current produced water availability within the basin is not large, but potential flow rates up to 257 million liters per day (68 million gallons per day (MGD)) are possible if CO2-enhanced oil recovery and coal bed methane recovery are implemented on a large scale. Produced water samples taken during the project tend to have dissolved solids concentrations between 10 and 100 g/L, and water from coal beds tends to have lower TDS values than water from oil fields. Current pretreatment and desalination technologies including filtration, adsorption, reverse osmosis (RO), and distillation can be used to treat produced water to a high quality level, with estimated costs ranging from $2.6 to $10.5 per cubic meter ($10 to $40 per 1000 gallons). Because of the distances between produced water sources and power plants, transportation costs tend to be greater than treatment costs. An optimization algorithm was developed to determine the lowest cost pipe network connecting sources and sinks. Total water costs increased with flow rate up to 26 million liters per day (7 MGD), and the range was from $4 to $16 per cubic meter

  10. Vibro-fluidized bed heat pump drying of mint leaves with respect to phenolic content, antioxidant activity, and color indices

    Directory of Open Access Journals (Sweden)

    Ataei Ardestani Seyed Majid

    2015-01-01

    Full Text Available Because of high porosity and stickiness of mint leaves, they could not be fluidized well during fluidization. In this study, a vibro-fluidized bed dryer assisted heat pump system was designed and fabricated to overcome this problem. The drying experiments were carried out at temperatures of 40, 50 and 60 °C. The quality of the dehydrated samples was assessed based on color indices, antioxidant activity, and total phenolic content. Drying process primarily occurred in falling rate period. The effective coefficient of moisture transfer of the samples was increased with air temperature and varied from 4.26656×10-11 to 2.95872×10-10 m2 s-1 for heat pump drying (HPD method, and 3.71918×10-11 to 1.29196×10-10 m2 s-1 for none-heat pump drying (NHPD method. The color indices for temperatures of 40 and 50 °C were very close to each other, whereas by increasing temperature to 60 °C, a remarkable loss of green color was observed. The highest phenolic content was found in methanolic extract for HPD at 60 °C, and NHPD at 50 °C contained the lowest amount of phenolic compounds. NHPD treatments showed lower antioxidant activity compared to HPD treatments at the same temperature due to the longer drying times.

  11. Closed Brayton cycle power system with a high temperature pellet bed reactor heat source for NEP applications

    International Nuclear Information System (INIS)

    Capitalizing on past and future development of high temperature gas reactor (HTGR) technology, a low mass 15 MWe closed gas turbine cycle power system using a pellet bed reactor heating helium working fluid is proposed for Nuclear Electric Propulsion (NEP) applications. Although the design of this directly coupled system architecture, comprising the reactor/power system/space radiator subsystems, is presented in conceptual form, sufficient detail is included to permit an assessment of overall system performance and mass. Furthermore, an attempt is made to show how tailoring of the main subsystem design characteristics can be utilized to achieve synergistic system level advantages that can lead to improved reliability and enhanced system life while reducing the number of parasitic load driven peripheral subsystems

  12. Thermodynamic evaluation of the Kalina split-cycle concepts for waste heat recovery applications

    International Nuclear Information System (INIS)

    The Kalina split-cycle is a thermodynamic process for converting thermal energy into electrical power. It uses an ammonia–water mixture as a working fluid (like a conventional Kalina cycle) and has a varying ammonia concentration during the pre-heating and evaporation steps. This second feature results in an improved match between the heat source and working fluid temperature profiles, decreasing the entropy generation in the heat recovery system. The present work compares the thermodynamic performance of this power cycle with the conventional Kalina process, and investigates the impact of varying boundary conditions by conducting an exergy analysis. The design parameters of each configuration were determined by performing a multi-variable optimisation. The results indicate that the Kalina split-cycle with reheat presents an exergetic efficiency by 2.8% points higher than a reference Kalina cycle with reheat, and by 4.3% points without reheat. The cycle efficiency varies by 14% points for a variation of the exhaust gas temperature of 100 °C, and by 1% point for a cold water temperature variation of 30 °C. This analysis also pinpoints the large irreversibilities in the low-pressure turbine and condenser, and indicates a reduction of the exergy destruction by about 23% in the heat recovery system compared to the baseline cycle. - Highlights: • The thermodynamic performance of the Kalina split-cycle is assessed. • The Kalina split-cycle is compared to the Kalina cycle, with and without reheat. • An exergy analysis is performed to evaluate its thermodynamic performance. • The impact of varying boundary conditions is investigated. • The Kalina split-cycle displays high exergetic efficiency for low- and medium-temperature applications

  13. COLLISION PROCESS DETAILS CONTROL THE HYDRODYNAMICS AND HEAT TRANSFER IN FLUIDIZED BED REACTORS

    Institute of Scientific and Technical Information of China (English)

    Masayuki; Horio

    2005-01-01

    In the '90s DEM simulation research was successful in exploring its potential in the simulation of fluidization phenomenaand in its application to the design of fluidized-bed processes. Nevertheless, not much progress has been made regardingthe realistic treatment of collision processes that are critical in determining macroscopic mode of fluidization. All throughthe second half of the '90s, the author investigated/demonstrated the issue by introducing different surface interactionscaused by formation of liquid and/or solid bridges, van der Waals force and the existence of surface roughness. In the firstpart of the presentation these are to be summarized and the tasks remaining are discussed. In the second part, are pre-sented the results from a newly developed force-deformation meter to demonstrate the significance of the surfaceroughness and its elasto-plastic characteristics.

  14. Flash pyrolysis of jatropha oil cake in electrically heated fluidized bed reactor

    International Nuclear Information System (INIS)

    Fluidized bed flash pyrolysis experiments have been conducted on a sample of jatropha oil cake to determine particularly the effects of particle size, pyrolysis temperature and nitrogen gas flow rate on the pyrolysis yields. The particle size, nitrogen gas flow rate and temperature of jatropha oil cake were varied from 0.3 to 1.18 mm, 1.25 to 2.4 m3/h and 350 to 550 oC. The maximum oil yield of 64.25 wt% was obtained at a nitrogen gas flow rate of 1.75 m3/h, particle size of 0.7-1.0 mm and pyrolysis temperature of 500 oC. The calorific value of pyrolysis oil was found to be 19.66 MJ/kg. The pyrolysis gas can be used as a gaseous fuel.

  15. Thermodynamic analysis for heat recovery steam generation of cogeneration gas turbine cycle with reheat

    Energy Technology Data Exchange (ETDEWEB)

    Mosafa, A.H. [Islamic Azad Univ., Bonab (Iran, Islamic Republic of); Mahmoudi, S.M.S.; Farshi, L.G. [Tabriz Univ., Tabriz (Iran, Islamic Republic of). Faculty of Mechanical Engineering

    2008-07-01

    Much attention has been given to reheat gas turbine cycles in recent years due to their high exhaust gas temperature and the possibility of using that waste heat in a steam generation system. In this study, a heat recovery steam generator (HRSG) was analyzed as an appliance for transferring heat between exhaust gases and water. Design parameters were optimized. The results showed that a decrease in the pinch point temperature difference resulted in an increase in both energetic and exergetic efficiency. As process steam pressure increased, exergetic efficiency increased significantly but energetic efficiency decreased. These efficiencies were less affected by variation in final temperature difference. However decreasing the final temperature difference resulted in an increase in the steam's mass flow rate. Therefore, in order to design an optimal HRSG in a combined system such as cogeneration gas turbine cycle with reheat, a proper value of parameters must be chosen depending on the demand for heat or power. 15 refs., 2 tabs., 14 figs.

  16. The Optimal Evaporation Temperature of Subcritical ORC Based on Second Law Efficiency for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Xu

    2012-03-01

    Full Text Available The subcritical Organic Rankine Cycle (ORC with 28 working fluids for waste heat recovery is discussed in this paper. The effects of the temperature of the waste heat, the critical temperature of working fluids and the pinch temperature difference in the evaporator on the optimal evaporation temperature (OET of the ORC have been investigated. The second law efficiency of the system is regarded as the objective function and the evaporation temperature is optimized by using the quadratic approximations method. The results show that the OET will appear for the temperature ranges investigated when the critical temperatures of working fluids are lower than the waste heat temperatures by 18 ± 5 K under the pinch temperature difference of 5 K in the evaporator. Additionally, the ORC always exhibits the OET when the pinch temperature difference in the evaporator is raised under the fixed waste heat temperature. The maximum second law efficiency will decrease with the increase of pinch temperature difference in the evaporator.

  17. Thermodynamic Optimization of the Operative Parameters for the Heat Recovery in Combined Power Plants

    Directory of Open Access Journals (Sweden)

    Alessandro Franco

    2001-03-01

    Full Text Available

    For the combined power plants, the optimization of the heat recovery steam generator (HRSG is of particular interest in order to improve the efficiency of the heat recovery from turbine exhaust gas and to maximize the power production in the steam cycle. The thermodynamic optimization is the first step of a power plant design optimization process. The aim of this paper is to provide thermodynamic tools for the optimal selection of the operative parameters of the HRSG, starting from which a detailed optimization of its design variables can be carried out. For the thermodynamic analysis, the selected objective is the minimization of thermal exergy losses, taking into account only the irreversibility due to the temperature difference between the hot and cold streams. Various HRSG configurations have been analyzed, from the simpler, a single evaporator to the common configuration of two-pressure steam generator with five different sections.

    •  This paper was presented at the ECOS'00 Conference in Enschede, July 5-7, 2000

  18. Themoeconomic optimization of triple pressure heat recovery steam generator operating parameters for combined cycle plants

    Directory of Open Access Journals (Sweden)

    Mohammd Mohammed S.

    2015-01-01

    Full Text Available The aim of this work is to develop a method for optimization of operating parameters of a triple pressure heat recovery steam generator. Two types of optimization: (a thermodynamic and (b thermoeconomic were preformed. The purpose of the thermodynamic optimization is to maximize the efficiency of the plant. The selected objective for this purpose is minimization of the exergy destruction in the heat recovery steam generator (HRSG. The purpose of the thermoeconomic optimization is to decrease the production cost of electricity. Here, the total annual cost of HRSG, defined as a sum of annual values of the capital costs and the cost of the exergy destruction, is selected as the objective function. The optimal values of the most influencing variables are obtained by minimizing the objective function while satisfying a group of constraints. The optimization algorithm is developed and tested on a case of CCGT plant with complex configuration. Six operating parameters were subject of optimization: pressures and pinch point temperatures of every three (high, intermediate and low pressure steam stream in the HRSG. The influence of these variables on the objective function and production cost are investigated in detail. The differences between results of thermodynamic and the thermoeconomic optimization are discussed.

  19. Same Recovery Level of Compressed Chinese Fir Wood Can Be Obtained Through Different Heating Fixation Pathways

    Institute of Scientific and Technical Information of China (English)

    Xiaoshu Tang; Zhao Guangjie; Nakao Tetsuya

    2003-01-01

    The recovery of compression set (RS) of wood after dry heating or steam treatment mainly depends on the temperature and time of treatment. For quantitative elucidation, a graph of intermediate RS was built with temperature (T) and time (t) as coordinates. In this graph (abbreviated as T-t planum), a series of curves of RS were created. This leads to a conclusion that same RS can be obtained by numerous different pathways. Further research on pathway equivalency based on T-t planum indicates that a low RS of 10% can be achieved definitely by different combinations of time and temperature. However, the fixation mechanism varies at different temperatures. On the equivalent pathways of higher recovery, the influence of temperature must be taken into consideration. The actual routes must be somewhat modified to achieve an expected result. This makes it possible for us to work out a best fixation pathway among all the possibilities, to eliminate the impact of heat on the mechanical properties of wood.

  20. Experimental and computational investigation of a MEMS-based boiler for waste heat recovery

    International Nuclear Information System (INIS)

    Highlights: • A microboiler with capillary channels for low temperature energy harvesting. • Complete thermodynamic analysis is completed. • The boiler is designed for minimum thermal losses. • Capability of capillary channels to pump at various pressure is investigated. - Abstract: Thermodynamically limited processes make waste heat abundant in availability. An Organic Rankine Cycle (ORC) steam powered micro system designed to scavenge waste heat from various sources (transportation, industries or solar) is presented. The key boiler component is fabricated and characterized in this work. The system design has been inspired by the various efforts implemented in development of micro heat recovery devices and engines. The complete system consists of three individual micro components (1) boiler, (2) free piston expander and (3) superheater. Specifically, design, fabrication techniques, test setup and results of the miniaturized boiler are presented in this paper. A key design feature of the boiler is the inclusion of capillary channels for fluid flow from the surrounding reservoirs to the heated area. The pressurized steam is created by the boiler as a result of phase transformation of the working fluid. This pressurized steam can be utilized to drive another MEMS device (PZT membranes, turbines, thermoelectric, etc.) to generate power. In this upgraded boiler design, radial capillary channels and a thin film glass steamdome were considered to improve the operating efficiency. These inclusions enhanced capillary flow, energy absorption via phase change, mass flow rate and operating pressure. The power inputs of 1.8 W and 2.7 W were selected to simulate and characterize the boiler performance based on real-world waste heat source temperatures. For these power inputs, the maximum power absorption efficiency demonstrated by the boiler via phase change of the working fluid was approximately 88%. The peak operating pressure demonstrated by the boiler was 8.5 k

  1. Thermodynamic analysis of a low-temperature waste heat recovery system based on the concept of solar chimney

    International Nuclear Information System (INIS)

    Highlights: • A low grade waste heat recovery system based on the concept of solar chimney is proposed. • The effects of three key factors on the system performance are examined. • Thermodynamics analysis is to find a better way to utilize low grade heat source efficiently. - Abstract: The utilization of low-temperature waste heat draws more and more attention due to serious energy crisis nowadays. This paper proposes a low-temperature waste heat recovery system based on the concept of solar chimney. In the system, low-temperature waste heat is used to heat air to produce an air updraft in the chimney tower. The air updraft propels a turbine fixed at the base of the chimney tower to convert waste heat into electricity. The mathematical model of the system is established based on first law and second law of thermodynamics. Hot water is selected as the representative of low-temperature waste heat sources for researching. The heat source temperature, ambient air temperature and area of heat transfer are examined to evaluate their effects on the system performance such as velocity of updraft, mass flow rate of air, power output, conversion efficiency, and exergy efficiency. The velocity of air demonstrates a better stability than the mass flow rate of air and the pressure difference when temperature of heat source, ambient air temperature or area of heat transfer changes

  2. Coal gasification by indirect heating in a single moving bed reactor: Process development & simulation

    Directory of Open Access Journals (Sweden)

    Junaid Akhlas

    2015-10-01

    Full Text Available In this work, the development and simulation of a new coal gasification process with indirect heat supply is performed. In this way, the need of pure oxygen production as in a conventional gasification process is avoided. The feasibility and energetic self-sufficiency of the proposed processes are addressed. To avoid the need of Air Separation Unit, the heat required by gasification reactions is supplied by the combustion flue gases, and transferred to the reacting mixture through a bayonet heat exchanger installed inside the gasifier. Two alternatives for the flue gas generation have been investigated and compared. The proposed processes are modeled using chemical kinetics validated on experimental gasification data by means of a standard process simulator (Aspen PlusTM, integrated with a spreadsheet for the modeling of a special type of heat exchanger. Simulation results are presented and discussed for proposed integrated process schemes. It is shown that they do not need external energy supply and ensure overall efficiencies comparable to conventional processes while producing syngas with lower content of carbon dioxide.

  3. How Fast Is Recovery of Impaired Glucose Tolerance after 21-Day Bed Rest (NUC Study in Healthy Adults?

    Directory of Open Access Journals (Sweden)

    Martina Heer

    2014-01-01

    Full Text Available Aim. We hypothesized that 4 days of normal daily activity after 21 days of experimental bed rest (BR will not reverse BR induced impaired glucose tolerance. Design. Glucose tolerance of seven male, healthy, untrained test subjects (age: 27.6 (3.3 years (mean (SD; body mass: 78.6 (6.4 kg; height: 1.81 (0.04 m; VO2 max: 39.5 (5.4 ml/kg body mass/min was studied. They stayed twice in the metabolic ward (crossover design, 21 days in bed and 7 days before and after BR each. Oral glucose tolerance tests were applied before, on day 21 of BR, and 5 and 14 days after BR. Results. On day 21 of BR, AUC120 min of glucose concentration was increased by 28.8 (5.2% and AUC120 min of insulin by 35.9 (10.2% (glucose: P<0.001; insulin: P=0.02. Fourteen days after BR, AUC120 min of serum insulin concentrations returned to pre-bed-rest concentrations (P=0.352 and AUC120 min of glucose was still higher (P=0.038. Insulin resistance did not change, but sensitivity index was reduced during BR (P=0.005. Conclusion. Four days of light physical workload does not compensate inactivity induced impaired glucose tolerance. An individually tailored and intensified training regime is mandatory in patients being in bed rest to get back to normal glucose metabolism in a reasonable time frame.

  4. Experimental and numerical analyses on a plate heat exchanger with phase change for waste heat recovery at off-design conditions

    Science.gov (United States)

    Cipollone, Roberto; Bianchi, Giuseppe; Di Battista, Davide; Fatigati, Fabio

    2015-11-01

    This paper analyzes the performances of an evaporator for small scale waste heat recovery applications based on bottoming Organic Rankine Cycles with net output power in the range 2-5 kW. The heat recovery steam generator is a plate heat exchanger with oil as hot stream and an organic fluid on the cold side. An experimental characterization of the heat exchanger was carried out at different operating points measuring temperatures, pressures and flow rates on both sides. The measurement data further allowed to validate a numerical model of the evaporator whereas heat transfer coefficients were evaluated comparing several literature correlations, especially for the phase-change of the organic fluid. With reference to a waste heat recovery application in industrial compressed air systems, multiple off-design conditions were simulated considering the effects of oil mass flow rate and temperature on the superheating of the organic fluid, a key parameter to ensure a proper operation of the expansion machine, thus of the energy recovery process.

  5. Reactors for heat production with good electrical generating efficiency. Recovery of heat in helium-cooled direct-cycle reactors with one or two compression stages

    International Nuclear Information System (INIS)

    In order to be realistic, an evaluation of the performance of helium-cooled direct-cycle reactors must be based on a preliminary study of the circuits and the architecture. This was the procedure adopted by the Department of Mechanical and Thermal Studies (Saclay Nuclear Research Centre) which recently developed a plant concept aimed at solving the various problems involved and also defined the sizes of the principal components. The circuits have been designed to obtain a good electrical generating efficiency but without prejudicing this it has also been attempted to obtain the best conditions for recovering heat from the coolants. Results are presented for the following cases: a two-compression-stage cycle with good electrical generating efficiency and non-preferential heat recovery; a two-compression-stage cycle with acceptable electrical generating efficiency and improved heat recovery; a single-compression-stage cycle for the production of electricity with recovery of heat in the form of hot water; a single-compression-stage cycle with large-scale production of heat in the form of steam and hot water. It appears that the characteristics of the hot water in the secondary recovery circuits are well suited to district heating. It should be noted that the overall performances of all the different variants are satisfactory for a helium temperature at the core outlet of 8000C, which is reasonable. (author)

  6. Parametric study of reverse electrodialysis using ammonium bicarbonate solution for low-grade waste heat recovery

    International Nuclear Information System (INIS)

    Highlights: • We characterized the influence of various parameters on the NH4HCO3-RED system. • We found the best power density at the concentrated solutions of 1.5 mol L−1 and the diluted solution of 0.01 mol L−1. • We obtained the higher power density of 0.77 W m−2 than previous studies. - Abstract: Waste heat recovery has attracted a significant attention because of the world growth in energy demand. In this paper, we report the study on an energy recovery system utilizing low-grade waste heat below 100 °C. This system called a thermal-driven electrochemical generator is composed of reverse electrodialysis (RED) power generation and thermal separation using waste heat. We especially focus on the experimental characterization of the RED process with ammonium bicarbonate (NH4HCO3) solution, which is known to be easily decomposed at the temperature around 60 °C. We characterized this NH4HCO3-RED system with various parameters including the concentration difference, the membrane type, the inlet flow rate, and the compartment thickness. We found the best power density at the concentrated solution of 1.5 mol L−1 and the diluted solution of 0.01 mol L−1. The maximum power density increases as the inlet flow rate increases or the compartment thickness decreases owing to the decrease in the internal resistance. We obtained the excellent power density of 0.77 W m−2, compared with the previous studies

  7. Heat Transfer Calculations for Normal Operations of a Fixed CST Bed Column

    International Nuclear Information System (INIS)

    In support of the crystalline silicotitanate (CST) ion exchange project of High-Level Waste (HLW) Process Engineering, heat transfer calculations have been made for a fully-loaded CST column during abnormal and normal operating conditions. The objective of the present work is to compute temperature distributions across the column when there is steady flow of salt solution through the CST column under normal conditions of the process operations

  8. Coupling of a radiative heat transfer model and a three-dimensional combustion model for a circulating fluidized bed furnace

    International Nuclear Information System (INIS)

    A 3D semi-empirical model for reactive two-phase flow in a circulating fluidized bed furnace (CFB3D) is modified by implementing the radiative zone method to solve the radiation heat transfer. The radiative properties of the gas and particle phase have been calculated using detailed information of gas and particle distribution obtained from the CFB3D model. A recently published WSGGM for oxygen-fired combustion has been used to calculate the absorption coefficient of gaseous combustion products. The results of implementing the radiative zonal approach have been compared with those obtained using empirical radiative correlations. The temperature field obtained by using the radiative zone method is more uniform than the one obtained by empirical correlation, and the total heat flux to the wall is slightly higher. The long distance effect of radiation has been found more important in the upper furnace where the gas is the dominant phase. Detailed discussion concerning the obtained results is presented.- Highlights: • Radiative zone model is used to analyze a large scale CFB furnace. • A semi-empirical model for CFB processes is presented. • The radiative effect of long distance is taken into account. • The geometric optic is used for radiative properties of particles. • The WSGGM is used for radiative properties of combustion gases

  9. Comparative analysis of a bottoming transcritical ORC and a Kalina cycle for engine exhaust heat recovery

    International Nuclear Information System (INIS)

    Highlights: • Thermal performance comparison of two eligible bottoming cycles is investigated. • Thermal match between the temperature profiles of working fluid and exhaust is considered. • Influences of the various-temperature heat source on the two WHR cycles are studied. • Bottoming transcritical ORC shows advantages at a certain ICE load. • Suitable working conditions for both of the bottoming cycles are given. - Abstract: A performance comparison of two types of bottoming cycles, including a Kalina cycle and a transcritical organic Rankine cycle (ORC) using working fluids with sliding-temperature boiling characteristics, is conducted in order to analyze energy saving of the sensible exhaust waste heat recovery (WHR) under various internal combustion engine (ICE) working conditions. Through quantitatively analyzing the relation between exhaust waste-heat behaviors and the ICE load of a commercial ICE, two bottoming subsystems models, including a transcritical ORC using some several Alkanes and a Kalina cycle using NH3–H2O as working fluids, are build under the same ICE various-temperature exhaust heat-source and air heat-sink conditions. Compared to Kalina cycle, the transcritical ORC shows prominent advantages on the overall thermal efficiency, low operation pressure and simple components configuration at the ICE load with exhaust temperature over 491 K. The optimal thermal performance of the transcritical ORC appears at the ICE load with the certain exhaust temperature of 569–618 K. However, thermodynamic performance of the bottoming transcritical ORC is worsened considerably at the ICE load with the exhaust temperature over or under the certain value. Moreover, the extremely high turbine expansion ratio requires a complex multi-stage turbine design and big turbine dimensions for the bottoming transcritical ORC using Alkanes-based working fluid

  10. Design sensitivity analysis of using various flow boiling correlations for a direct evaporator in high-temperature waste heat recovery ORCs

    OpenAIRE

    Kaya, Alihan; Lecompte, Steven; Lazova, Marija; De Kerpel, Kathleen; De Paepe, Michel

    2015-01-01

    High-temperature waste heat (250°C-400°C) sources being created by industrial operations such as metallurgical industry, incinerators, combustion engines, annealing furnaces, drying, baking, cement production etc. are being utilized in Organic Rankine cycle (ORC) waste heat recovery systems. Alongside indirect ORC evaporators having intermediate heat carrier loops, ORC waste heat recovery can also be done through a direct evaporator (e.g. tube bundles) applied on a heat source. In an evaporat...

  11. Design and modeling of an advanced marine machinery system including waste heat recovery and removal of sulphur oxides

    DEFF Research Database (Denmark)

    Frimann Nielsen, Rasmus; Haglind, Fredrik; Larsen, Ulrik

    2013-01-01

    In order to reduce the formation of acid rain and its harmful effects, stricter legislations on emissions of sulphur oxides from ships applies as of 2015 in emission control areas and globally in 2020 by the international maritime organization (IMO). Consequently, prices on low sulphur fuels...... of the machinery system. The wet sulphuric acid process has shown to be an effective way of removing sulphur oxides from flue gas of land-based coal fired power plants. Moreover, organic Rankine cycles are suitable for heat to power conversion for low temperature heat sources. This paper is aimed at designing......-stroke diesel engine and a conventional waste heat recovery system. The results suggest that an organic Rankine cycle placed after the conventional waste heat recovery system is able to extract the sulphuric acid from the exhaust gas, while at the same time increase power generation from waste heat by 32...

  12. Experimental and numerical analysis of the optimized finned-tube heat exchanger for OM314 diesel exhaust exergy recovery

    International Nuclear Information System (INIS)

    Highlights: • An optimized finned-tube heat exchanger is modeled. • Artificial Neural Networks and Genetic Algorithm are applied. • Exergy recovery from exhaust of a diesel engine is studied. - Abstract: In this research, a multi objective optimization based on Artificial Neural Network (ANN) and Genetic Algorithm (GA) are applied on the obtained results from numerical outcomes for a finned-tube heat exchanger (HEX) in diesel exhaust heat recovery. Thirty heat exchangers with different fin length, thickness and fin numbers are modeled and those results in three engine loads are optimized with weight functions for pressure drop, recovered heat and HEX weight. Finally, two cases of HEXs (an optimized and a non-optimized) are produced experimentally and mounted on the exhaust of an OM314 diesel engine to compare their results in heat and exergy recovery. All experiments are done for five engine loads (0%, 20%, 40%, 60% and 80% of full load) and four water mass flow rates (50, 40, 30 and 20 g/s). Results show that maximum exergy recovers occurs in high engine loads and optimized HEX with 10 fins have averagely 8% second law efficiency in exergy recovery

  13. Performance analysis of a waste heat recovery thermoelectric generation system for automotive application

    International Nuclear Information System (INIS)

    Graphical abstract: A new automotive exhaust-based thermoelectric generator and its “four-TEGs” system are constructed, and the performance characteristics of system are discussed through road test and revolving drum test. - Highlights: • The automotive thermoelectric generator system was constructed and studied. • Road test and revolving drum test were used to measure the output power. • A performance of 201.7 V (open circuit voltage)/944 W obtained. - Abstract: Thermoelectric power generators are one of the promising green energy sources. In this case study, an energy-harvesting system which extracts heat from an automotive exhaust pipe and turns the heat into electricity by using thermoelectric power generators (TEGs) has been constructed. The test bench is developed to analysis the performance of TEG system characteristics, which are undertaken to assess the feasibility of automotive applications. Based on the test bench, a new system called “four-TEGs” system is designed and assembled into prototype vehicle called “Warrior”, through the road test and revolving drum test table, characteristics of the system such as hot-side temperature, cold-side temperature, open circuit voltage and power output are studied, and a maximum power of 944 W was obtained, which completely meets the automotive application. The present study shows the promising potential of using this kind of thermoelectric generator for low-temperature waste heat recovery vehicle

  14. Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed

    OpenAIRE

    2014-01-01

    Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed’s fluid flow field. For 0.5–0.25 mm circuit board particles, metal ...

  15. Heat and mass transfer through a thick bed of cocoa beans during drying

    Science.gov (United States)

    Nganhou, J.

    This article relates to the establishment of macroscopic equations of thick and fixed hygroscopical porous medium allowing an analysis of couply phenomena of heat and mass transfers in drying operation. The drying is done through forced convection by imposing a circulation of hot air across the layer. The authors then make their study particular to the case of thick layer of cocoa beans grown in the region of Yaounde in cameroon. A study realized on a prototype constructed and tested in the laboratory enables the validation of the proposed model.

  16. Design of heat recovery system in an aluminium cast house : Design av varmegjenvinningssystem i et aluminium smelteverk

    OpenAIRE

    Albert, Daniel

    2012-01-01

    In this diploma thesis, the possibilities to enhance the process production and energy efficiencyas well as the energy recovery potential of PFA 2 at Hydro-Sunndalsøra have been determined.To identify the potentials for energy recovery, it has been conducted energy balances. The resultsfrom the balances give an overview of the waste heat sources and their total energy content, togetherwith the temperatures at which they are available. The total energy in the waste heatsources for PFA 2 w...

  17. Application of computational fluid dynamics for the simulation of cryogenic molecular sieve bed absorber of hydrogen isotopes recovery system for Indian LLCB-TBM

    International Nuclear Information System (INIS)

    One of the most challenging tasks in the design of the fuel cycle system lies in the effective design of Tritium Extraction System (TES) which involves proper extraction and purification of tritium in the fuel cycle of the fusion reactor. Indian Lead Lithium cooled Ceramic Breeder Test Blanket Module (LLCB-TBM) would extract hydrogen isotopes through Cryogenic Molecular Sieve Bed (CMSB) adsorber system. A prototype Hydrogen Isotopes Recovery System (HIRS) is being developed to validate the concepts for tritium extraction by adsorption mass transfer mechanism. In this study, a design model has been developed and analyzed to simulate the adsorption mass transfer kinetics in a fixed bed adsorption column. The simulation leads primarily to effective design of HIRS, which is a state-of-the-art technology. The paper describes the process simulation approach and the results of Computational Fluid Dynamics (CFD) analysis. The effects of different operating conditions are studied to investigate their influence on the hydrogen isotopes adsorption capacity. The results of the present simulation study would be used to understand the best optimized transport phenomenon before realizing the TES as a system for LLCB-TBM. (authors)

  18. Non-uniform groundwater discharge across a stream bed: Heat as a tracer

    DEFF Research Database (Denmark)

    Jensen, Jannick Kolbjørn; Engesgaard, Peter Knudegaard

    2011-01-01

    steady throughout the period. On the other hand, discharge to the stream at the opposite bank near a steep hillslope decreased signifi cantly toward the end of the period (early June), which was a¿ ributed to a drop in the water table on this side of the stream. The results from the O me series analysis......Time series analysis of conO nuous streambed temperature during a period of 47 d revealed that discharge to a stream is nonuniform, with strongly increasing verO cal fl uxes throughout the top 20 cm of the streambed–aquifer interface. An analyO cal soluO on to the transient heat transport equaO on...... were compared with seepage meter measurements and the results from a steady-state analyO cal soluO on to the heat transport equaO on. The diff erent methods agreed on the pa¿ ern of discharge across the stream width, and the mean values during the studied period generally agreed well but with diff...

  19. Investigation of Strength Recovery in Welds of NUCu-140 Steel Through Multipass Welding and Isothermal Post-Weld Heat Treatments

    Science.gov (United States)

    Bono, Jason T.; DuPont, John N.; Jain, Divya; Baik, Sung-Il; Seidman, David N.

    2015-11-01

    NUCu-140 is a ferritic copper precipitation-strengthened steel that is a candidate material for use in many naval and structural applications. Previous work has shown that the heat-affected zone (HAZ) and fusion zone (FZ) of NUCu-140 exhibit softening that is due to dissolution of the copper-rich precipitates. This study aims to recover the FZ and HAZ strength by re-precipitation of the copper-rich precipitates through either multiple weld passes or an isothermal post-weld heat treatment (PWHT). The potential use of multiple thermal cycles was investigated with HAZ simulations using a Gleeble thermo-mechanical simulator. The HAZ simulations represented two weld thermal cycles with different combinations of peak temperatures during the initial and secondary weld passes. To investigate the potential for a PWHT for strength recovery, gas tungsten arc weld samples were isothermally heated for various times and temperatures. Microhardness measurements revealed no strength recovery in the multipass HAZ samples. The time-dependent precipitate characteristics were modeled under the HAZ thermal cycle conditions, and the results showed that the lack of strength recovery could be attributed to insufficient time for re-precipitation during the secondary weld pass. Conversely, full strength recovery in the HAZ was observed in the isothermally heat treated samples. Atom probe tomography analysis correlated this strength recovery to re-precipitation of the copper-rich precipitates during the isothermal PWHT.

  20. Heating System of High Temperature Biogas Digester by Solar Energy and Methane Liquid Heat Recovery Heat Pump%太阳能-沼液余热式热泵高温厌氧发酵加温系统

    Institute of Scientific and Technical Information of China (English)

    裴晓梅; 石惠娴; 朱洪光; 龙惟定

    2012-01-01

    A heating system of biogas digester was developed to avoid area limitations of buried wells in the heating system of biogas digester by ground-source heat pump, in which the heat energy was supplied by hot water from waste heat recovery coupled with solar- assisted heat pump. The key parameters such as the heat load of digester, waste heat recovery rate of the methane liquid, medium and high heat pump, the solar energy collector area and so on werecalculated. The results show that this system can guarantee the temperature of 50+2℃ in the digester, the heat recovery rate of the methane liquid can reach upto 70%. The system is characterized by that the solar energy and waste heat recovery of the methane liquid serve as the low-graded heat sources of the heat pump. There a're three kinds of running modes including the sloar energy heating directly, the solar energy low level heat sources heat pump, and the combination of the solar energy and waste heat recovery low - graded heat resources heat pump and so on. The waste heat recovery technique can make full use of energy of the system and prevent thermal pollution.%针对地源热泵式沼气池加温系统需要打地埋井及铺设地埋管受地质水质局限等问题,系统构建了太阳能—沼液余热式热泵高温厌氧发酵加温系统.对系统发酵池热负荷、沼液余热回收率、中高温热泵机组、太阳能集热装置等关键参数进行了理论计算,得出系统能够保证发酵池温度50±2℃,沼液余热回收量可以达到系统总需要热量的70%.系统特点在于采用太阳能和沼液余热联合作为中高温热泵低位热源并确立其三种运行模式,包括太阳能直接加温模式,太阳能低位热源—热泵加热模式和太阳能—沼液余热回收联合式热泵加温模式.

  1. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Alloys for design and construction of structural components needed to contain process streams and provide internal structures in advanced heat recovery and hot gas cleanup systems were examined. Emphasis was placed on high-strength, corrosion-resistant alloys for service at temperatures above 1000 {degrees}F (540{degrees}C). Data were collected that related to fabrication, joining, corrosion protection, and failure criteria. Alloys systems include modified type 310 and 20Cr-25Ni-Nb steels and sulfidation-resistance alloys HR120 and HR160. Types of testing include creep, stress-rupture, creep crack growth, fatigue, and post-exposure short-time tensile. Because of the interest in relatively inexpensive alloys for high temperature service, a modified type 310 stainless steel was developed with a target strength of twice that for standard type 310 stainless steel.

  2. Model Predictive Control of Offshore Power Stations With Waste Heat Recovery

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Chan, Richard; Li, Xiangan; Lyengar, Krishna; Haglind, Fredrik; Ydstie, Erik

    2016-01-01

    control (MPC) coupled with a steady-state performance optimizer has been developed in the SIMULINK language and is documented in the paper. The test case is the regulation of a power system serving an oil and gas platform in the Norwegian Sea. One of the three gas turbines is combined with an organic......The implementation of waste heat recovery units on oil and gas offshore platforms demands advances in both design methods and control systems. Model-based control algorithms can play an important role in the operation of offshore power stations. A novel regulator based on a linear model predictive...... Rankine cycle (ORC) turbogenerator to increase the energy conversion efficiency. Results show a potential reduction of frequency drop up to 40%for a step in the load set-point of 4 MW, compared to proportional–integral control systems. Fuel savings in the range of 2–3% are also expected by optimizing on...

  3. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, modified alloy 800, and two sulfidation resistant alloys: HR160 and HR120. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700{degrees}C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925{degrees}C with good weldability and ductility.

  4. A comparison of advanced heat recovery power cycles in a combined cycle for large ships

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Sigthorsson, Oskar; Haglind, Fredrik

    2014-01-01

    working fluids possess high global warming potentials and hazard levels. It is concluded that the ORC has the greatest potential for increasing the fuel efficiency, and the combined cycle offers very high thermal efficiency. While being less efficient, the steam cycle has the advantages of being well......Strong motivation exists within the marine sector to reduce fuel expenses and to comply with ever stricter emission regulations. Heat recovery can address both of these issues. The ORC (organic Rankine cycle), the Kalina cycle and the steam Rankine cycle have received the majority of the focus in...... the literature. In the present work we compare these cycles in a combined cycle application with a large marine two-stroke diesel engine. We present an evaluation of the efficiency and the environmental impact, safety concerns and practical aspects of each of the cycles. A previously validated...

  5. Investigation of austenitic alloys for advanced heat recovery and hot-gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, and modified alloy 800. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700 C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925 C with good weldability and ductility.

  6. Dynamic test on waste heat recovery system with organic Rankine cycle

    Institute of Scientific and Technical Information of China (English)

    王志奇; 刘力文; 夏小霞; 周乃君

    2014-01-01

    Dynamic performance is important to the controlling and monitoring of the organic Rankine cycle(ORC) system so to avoid the occurrence of unwanted conditions. A small scale waste heat recovery system with organic Rankine cycle was constructed and the dynamic behavior was presented. In the dynamic test, the pump was stopped and then started. In addition, there was a step change of the flue gas volume flow rate and the converter frequency of multistage pump, respectively. The results indicate that the working fluid flow rate has the shortest response time, followed by the expander inlet pressure and the expander inlet temperature. The operation frequency of pump is a key parameter for the ORC system. Due to a step change of pump frequency (39.49−35.24 Hz), the expander efficiency and thermal efficiency drop by 16%and 21%within 2 min, respectively. Besides, the saturated mixture can lead to an increase of the expander rotation speed.

  7. Prediction of heat recovery steam generator (HRSG) noise attenuation using scale model testing

    Energy Technology Data Exchange (ETDEWEB)

    Bracken, M.; Barman, M.; Gambino, V. [Aercoustics Engineering Limited, Toronto, ON (Canada)

    1996-08-01

    An investigation was undertaken to determine whether scale modelling was effective for the study of (1) reactive attenuation on the gas flow path of heat recovery steam generators (HRSGs), (2) attenuation due to diffusion and scattering of sound, and (3) propagation loss due to flow resistivity of the tube bundles. MIDAS, a state-of-the-art measurement system, suitable for use with small models, and a microphone capable of ultrasonic measurement, were used. The noise source used was supplied by a high voltage spark source. The methodology used in the study, and some of the initial results of the scale model testing were described. A review of the initial results showed that it will be possible to model reactive effects, viscous loss and diffusion and scattering. 2 refs., 1 fig.

  8. Optimization of heat recovery steam generators for combined cycle gas turbine power plants

    Energy Technology Data Exchange (ETDEWEB)

    Valdes, M. [Universidad Politecnica de Madrid (Spain). Departamento de Ingenieria Energetica y Fluidomecanica; Rapun, J.L. [IBERDROLA Ingenieria y Consultoria, Madrid (Spain)

    2001-08-01

    The heat recovery steam generator (HRSG) is one of the few components of combined cycle gas turbine power plants tailored for each specific application. Any change in its design would directly affect all the variables of the cycle and therefore the availability of tools for its optimization is of the greatest relevance. This paper presents a method for the optimization of the HRSG based on the application of influence coefficients. The influence coefficients are a useful mathematical tool in design optimization problems. They are obtained after solving the equations of the system through the Newton-Raphson method. The main advantage of the proposed method is that it permits a better understanding of the influence of the design parameters on the cycle performance. The study of the optimization of the distribution of the boiler area between its different components is presented as an example of the proposed technique. (author)

  9. Study on an advanced adsorption desalination cycle with evaporator–condenser heat recovery circuit

    KAUST Repository

    Thu, Kyaw

    2011-01-01

    This paper presents the results of an investigation on the efficacy of a silica gel-water based advanced adsorption desalination (AD) cycle with internal heat recovery between the condenser and the evaporator. A mathematical model of the AD cycle was developed and the performance data were compared with the experimental results. The advanced AD cycle is able to produce the specific daily water production (SDWP) of 9.24 m3/tonne of silica gel per day at 70 °C hot water inlet temperature while the corresponding performance ratio (PR) is comparatively high at 0.77. It is found that the cycle can be operational at 50 °C hot water temperature with SDWP 4.3. The SDWP of the advanced cycle is almost twice that of the conventional AD cycle. © 2010 Elsevier Ltd. All rights reserved.

  10. Analysis of heat recovery from a spray dryer by recirculation of exhaust air

    International Nuclear Information System (INIS)

    Highlights: • We study a spray dryer with heat recovery by partial recirculation of exhaust air. • We examine effects of process parameters on energy efficiency and energy savings. • Decreasing drying air temperature and flow rate will increase energy efficiency. • Increasing recirculation ratio and slurry feed rate will increase energy efficiency. - Abstract: Model simulations were employed to investigate the influences of process parameters on the energy recovery in spray drying process that partially recycle the exhaust drying gas. The energy efficiency and energy saving were studied for various values of recirculation ratios with respect to the temperature and flow rate of the drying air, slurry feed rate and concentration of slurry in spray drying of advanced ceramic materials. As a result, significant gains in energy efficiency and energy saving were obtained for a spray drying system with high recirculation ratio of exhaust air. The high slurry feed rate and the low slurry concentration, inlet drying air temperature and drying air flow rate enhanced the energy efficiency of spray drying system. However, the high energy saving was obtained in spray dryers operating at low slurry feed rate and high slurry concentration

  11. CO2-Dissolved - A Novel Approach to Combining CCS and Geothermal Heat Recovery

    International Nuclear Information System (INIS)

    This paper presents the outline of the CO2-Dissolved project whose objective is to assess the technical-economic feasibility of a novel CCS concept integrating geothermal energy recovery, aqueous dissolution of CO2 and injection via a doublet system, and an innovative post-combustion CO2 capture technology. Compared to the use of a supercritical phase, this approach offers substantial benefits in terms of storage safety, due to lower brine displacement risks, lower CO2 escape risks, and the potential for more rapid mineralization. However, the solubility of CO2 in brine will be a limiting factor to the amount of CO2 that can be injected. Consequently, and as another contributing novel factor, this proposal targets low to medium range CO2 emitters (ca. 10-100 kt/yr), that could be compatible with a single doublet installation. Since it is intended to be a local solution, the costs related to CO2 transport would then be dramatically reduced, provided that the local underground geology is favorable. Finally, this project adds the potential for energy and/or revenue generation through geothermal heat recovery. This constitutes an interesting way of valorization of the injection operations, demonstrating that an actual synergy between CO2 storage and geothermal activities may exist. (authors)

  12. The Brayton Cycle heat pump for solvent recovery and pollution control

    International Nuclear Information System (INIS)

    The Brayton Cycle heat pump technology for the recovery of solvent and prevention of emissions is relatively new. Like most new technologies, it is a combination of older concepts, ideas and types of processes put together in a unique way. As a result, proven equipment enables achievement of extremely low condensing temperatures at relatively low cost. The Brayton Cycle is a thermodynamic principle. It was used first for a turbine engine, but more recently it has been used for a variety of other kinds of processes including refrigeration. A great variety of methods are used for emission control including adsorption, direct condensation, absorption in a fluid, and incineration or destruction. The Brayton Cycle technology actually fits into two of these categories, adsorption and direct condensation. Since it is a refrigeration process, it can be used to condense solvents from a solvent-laden air stream. The advantage of this particular process over other refrigeration methods is that lower temperatures can be achieved more easily. In fact, temperatures as low as -150 degrees F have been used to recover solvents in this manner. That happens to be the freezing point of methylene chloride which is a very volatile compound. High recovery efficiencies can be obtained for a whole variety of organic materials. 8 figs., 1 tab

  13. A comparison of advanced heat recovery power cycles in a combined cycle for large ships

    International Nuclear Information System (INIS)

    Strong motivation exists within the marine sector to reduce fuel expenses and to comply with ever stricter emission regulations. Heat recovery can address both of these issues. The ORC (organic Rankine cycle), the Kalina cycle and the steam Rankine cycle have received the majority of the focus in the literature. In the present work we compare these cycles in a combined cycle application with a large marine two-stroke diesel engine. We present an evaluation of the efficiency and the environmental impact, safety concerns and practical aspects of each of the cycles. A previously validated numerical engine model is combined with a turbocharger model and bottoming cycle models written in Matlab. Genetic algorithm optimisation results suggest that the Kalina cycle possess no significant advantages compared to the ORC or the steam cycle. While contributing to very high efficiencies, the organic working fluids possess high global warming potentials and hazard levels. It is concluded that the ORC has the greatest potential for increasing the fuel efficiency, and the combined cycle offers very high thermal efficiency. While being less efficient, the steam cycle has the advantages of being well proven, harmless to the environment as well as being less hazardous in comparison. - Highlights: • We compare steam, ORC (organic Rankine cycle) and Kalina cycles for waste heat recovery in marine engines. • We evaluate the efficiency and important qualitative differences. • The Kalina cycle presents no apparent advantages. • The steam cycle is well known, harmless and has a high efficiency. • The ORC has the highest efficiency but also important drawbacks

  14. Performance Analysis and Working Fluid Selection of a Supercritical Organic Rankine Cycle for Low Grade Waste Heat Recovery

    OpenAIRE

    Yourong Li; Shuangying Wu; Xiaoxiao Xu; Chao He; Chao Liu; Hong Gao

    2012-01-01

    The performance analysis of a supercritical organic Rankine cycle system driven by exhaust heat using 18 organic working fluids is presented. Several parameters, such as the net power output, exergy efficiency, expander size parameter (SP), and heat exchanger requirement of evaporator and the condenser, were used to evaluate the performance of this recovery cycle and screen the working fluids. The results reveal that in most cases, raising the expander inlet temperature i...

  15. Analysis of Exhaust Gas Waste Heat Recovery and Pollution Processing for Z12V190 Diesel Engine

    OpenAIRE

    Hou Xuejun; Gao Deli

    2012-01-01

    With the increasingly prominent problem regarding rapid economy development and the gradually serious environmental pollution, the waste heat recovery and waste gas pollution processing have received significant attention. Z12V190 diesel engine has high fuel consumption and low thermal efficiency and releases large amounts of exhaust gas and waste heat into the atmosphere, causing serious problems of energy waste and environmental pollution. In this work, the diesel engine exhaust gas compone...

  16. The use of mechanical ventilation with heat recovery for controlling radon and radon-daughter concentrations

    International Nuclear Information System (INIS)

    An energy research house in Maryland was found to have radon concentrations far in excess of recommended guidelines. A mechanical ventilation system with heat recovery was installed in this house to test its effectiveness as an energy-efficient control technique for indoor radon. Radon concentration was monitored continuously for two weeks under varying ventilation conditions (0.07 to 0.8 air changes per hour (ach)) and radon daughter concentrations were measured by grab-sample techniques about nine times daily during this period. At ventilation rates of 0.6 ach and higher radon and radon daughter levels dropped below guidelines for indoor concentrations. Comparison with other studies indicates that indoor radon buildup may be a problem in a considerable portion of houses characterized by their low infiltration rates. The use of mechanical ventilation systems with air-to-air heat exchangers may offer a practical, cost-effective, and energy-efficient means of alleviating not only the radon problem specifically but also the general deterioration of indoor air quality in houses designed or retrofitted to achieve low infiltration

  17. Thermodynamic analysis and performance optimization of an Organic Rankine Cycle (ORC) waste heat recovery system for marine diesel engines

    International Nuclear Information System (INIS)

    Escalating fuel prices and imposition of carbon dioxide emission limits are creating renewed interest in methods to increase the thermal efficiency of marine diesel engines. One viable means to achieve such improved thermal efficiency is the conversion of engine waste heat to a more useful form of energy, either mechanical or electrical. Organic Rankine Cycle (ORC) has been demonstrated to be a promising technology to recover waste heat. This paper examines waste heat recovery of a marine diesel engine using ORC technology. Two separated ORC apparatuses for the waste heat from both the jacket cooling water and the engine exhaust gas are designed as the traditional recovery system. The maximum net power output is chosen as the evaluation criterion to select the suitable working fluid and define the optimal system parameters. To simplify the waste heat recovery, an optimized system using the jacket cooling water as the preheating medium and the engine exhaust gas for evaporation is presented. The influence of preheating temperature on the system performance is evaluated to define the optimal operating condition. Economic and off-design analysis of the optimized system is conducted. The simulation results reveal that the optimized system is technically feasible and economically attractive. - Highlights: • ORC is used to recover waste heat from both exhaust gas and jacket cooling water. • Comparative study is conducted for different ORC systems. • Thermal performance, system structure and economic feasibility are considered. • Optimal preheating temperature of the system is selected

  18. 炼油厂废热回收利用%The Recovery and Exploitation of Heat Discarded from Oil Refinery

    Institute of Scientific and Technical Information of China (English)

    陈晓东

    2012-01-01

    针对江苏某炼油厂废热回收问题为研究方向,将硫回收车间需要降温的净化水进行热量回收,采用HTFS软件作为换热器计算的工具,设计换热器使用净化水加热原工艺设置用1.0 MPa蒸汽加热的原油,降温后的净化水可直接送至减压、加氢等装置回收利用,以实现原油加热、净化水降温且最终达到节能的目的。%Based on the study direction of the hot recovery problems of some oil refinerysf in Jiangsu,reduce the heat the decontamination water that the sulphur recover the car to need to be reduce the heat carries on the calories recovery,adopting HTFS software as the tool of changing hot and calculating,making the the hot change machine use the 1.0 MPa steam heating crude oil that the original craft for decontamination water heating use,and the decontamination water can directly send to the decompression,hydrogenation,etc.to equip the recovery exploitation,to carry out the crude oil heating,decontamination the water reduce the heat and end attain the purpose of economy energy.

  19. Final Scientific/Technical Report [Recovery Act: Districtwide Geothermal Heating Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Chatterton, Mike

    2014-02-12

    The Recovery Act: Districtwide Geothermal Heating Conversion project performed by the Blaine County School District was part of a larger effort by the District to reduce operating costs, address deferred maintenance items, and to improve the learning environment of the students. This project evaluated three options for the ground source which were Open-Loop Extraction/Re-injection wells, Closed-Loop Vertical Boreholes, and Closed-Loop Horizontal Slinky approaches. In the end the Closed-Loop Horizontal Slinky approach had the lowest total cost of ownership but the majority of the sites associated with this project did not have enough available ground area to install the system so the second lowest option was used (Open-Loop). In addition to the ground source, this project looked at ways to retrofit existing HVAC systems with new high efficiency systems. The end result was the installation of distributed waterto- air heat pumps with water-to-water heat pumps installed to act as boilers/chillers for areas with a high ventilation demand such as they gymnasiums. A number of options were evaluated and the lowest total cost of ownership approach was implemented in the majority of the facilities. The facilities where the lowest total cost of ownership approaches was not selected were done to maintain consistency of the systems from facility to facility. This project had a number of other benefits to the Blaine County public. The project utilizes guaranteed energy savings to justify the levy funds expended. The project also developed an educational dashboard that can be used in the classrooms and to educate the community on the project and its performance. In addition, the majority of the installation work was performed by contractors local to Blaine County which acted as an economic stimulus to the area during a period of recession.

  20. Thermo-economic optimization of Regenerative Organic Rankine Cycle for waste heat recovery applications

    International Nuclear Information System (INIS)

    Highlights: • Thermo-economic optimization of regenerative ORC is performed. • Optimization is performed using multi objective genetic algorithm. • Objective function is maximum cycle efficiency and minimum specific investment. • Evaporation pressure, pinch point and superheat are decision variables. • Sensitivity analysis is performed to investigate effect of decision variables. - Abstract: Organic Rankine Cycle (ORC) is low grade and waste heat conversion technology. The current article deal with the thermo-economic optimization of basic ORC and regenerative ORC for waste heat recovery applications under constant heat source condition. Thermal efficiency and specific investment cost of basic ORC, single stage regenerative and double stage regenerative ORC has been optimized by using Non-dominated Sorting Genetic Algorithm-II (NSGA-II). Maximum thermal efficiency and minimum specific investment cost were selected as objective functions and relative increase in thermal efficiency and cost has been analyzed taking the basic ORC as base case. The constraint set consist of evaporation pressure, superheat, pinch point temperature difference in evaporator and condenser. The optimization was performed for five different working fluids. The optimization result show that R245fa is best working under considered conditions and basic ORC has low specific investment cost and thermal efficiency compared to regenerative ORC. R245fa is low boiling organic fluid, which has high degree of thermal stability and compatible with common construction materials of ORC. The average increase in thermal efficiency from basic ORC to single stage regenerative ORC was 1.01% with an additional cost of 187 $/kW while from basic ORC to double stage regenerative ORC was 1.45% with an average increase in cost of 297 $/kW. The sensitivity analysis was also performed to investigate the effect of operating conditions which show that evaporation pressure has promising effect on thermal