WorldWideScience

Sample records for unit tube-and-shell heat

  1. Aplicación del Método de la Colonia de Hormigas Mixto a la optimización de intercambiadores de calor de tubo y coraza//Application of the Mixed Ant Colony Method to the optimization of tube and shell heat exchangers

    Directory of Open Access Journals (Sweden)

    Maida Bárbara Reyes‐Rodríguez

    2014-05-01

    Full Text Available Los procesos de transferencia de calor sonuno de los problemas más importantes a resolver en el campo de la Ingeniería. Entre los equipos más usados en la industria para realizar la transferencia de calor están los intercambiadores de calor de tubo y coraza. En el presente trabajo se desarrolla el procedimiento para la optimización del diseño de estos equipos utilizando el método de Kern y aplicando el algoritmo de la colonia de hormigas. Se aplica el mismo a tres ejemplos concretos y los resultados obtenidos se comparan con los obtenidos aplicando otros métodos de la inteligencia artificial. Se optimizan los principales parámetros geométricos de los intercambiadores de calor de tubo y coraza para lograr un menor costo de los mismos. Se demuestra la eficacia del nuevo procedimiento MACO (Mixed Ant Colony Optimization, en el proceso de optimización desde el punto de vista económico utilizando diferentes casos de estudios.Palabras claves: intercambiadores de calor, colonia de hormigas, método de Kern.______________________________________________________________________________AbstractHeat transfer processes are one of the most important problems to be solved in the field of Engineering. Among the most widely used equipment for heat transfer in the industry are the shell and tube heat exchangers. This paper develops the procedure for optimizing the design of shell and tube heat exchangers using the method of Kern and applying the ant colony algorithm. The procedure has been applied to three specific examples and the results obtained are compared with those obtained by applying other methods of artificial intelligence. The main geometric parameters of shell and tube heat exchangers are optimized, to achieve a lower cost of the exchanger. The efficacy of the new procedure MACO (Mixed Ant Colony Optimization for the optimization process from economically point of view was demonstrated, using different case studies.Key words: heat

  2. Numerical model for the thermal-hydraulic solution of shell-and-U-tubes heat exchanger with segmental baffles

    International Nuclear Information System (INIS)

    Baptista Filho, Benedito Dias

    1979-01-01

    A numerical model has been developed to calculate the flow, pressure and temperature distribution of steady-state |for the tube and shell-side fluids in a shell-and-U-tubes heat exchanger with segmental baffles. It was based on the Subchannel Analysis Method- The model, checked with experimental results from one heat exchanger, predicted with good accuracy outlet temperatures for both fluids. The method, implemented ' in a computer program of low cost and easy application, can be used in the design and performance evaluation of commercial units.(author)

  3. Indoor unit for electric heat pump

    Science.gov (United States)

    Draper, R.; Lackey, R.S.; Fagan, T.J. Jr.; Veyo, S.E.; Humphrey, J.R.

    1984-05-22

    An indoor unit for an electric heat pump is provided in modular form including a refrigeration module, an air mover module, and a resistance heat package module, the refrigeration module including all of the indoor refrigerant circuit components including the compressor in a space adjacent the heat exchanger, the modules being adapted to be connected to air flow communication in several different ways as shown to accommodate placement of the unit in various orientations. 9 figs.

  4. Installation guidelines for Solar Heating System, single-family residence at New Castle, Pennsylvania

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    The Solar Heating System installer guidelines are provided for each subsystem and includes testing and filling the system. This single-family residential heating system is a solar-assisted, hydronic-to-warm-air system with solar-assisted domestic water heating. It is composed of the following major components: liquid cooled flat plate collectors; water storage tank; passive solar-fired domestic water preheater; electric hot water heater; heat pump with electric backup; solar hot water coil unit; tube-and-shell heat exchanger, three pumps, and associated pipes and valving in an energy transport module; control system; and air-cooled heat purge unit. Information is also provided on the operating procedures, controls, caution requirements, and routine and schedule maintenance. Information consists of written procedures, schematics, detail drawings, pictures and manufacturer's component data.

  5. Heat stress assessment in artistic glass units.

    Science.gov (United States)

    d'AMBROSIO Alfano, Francesca Romana; Palella, Boris Igor; Riccio, Giuseppe; Bartalini, Massimo; Strambi, Fabio; Malchaire, Jacques

    2018-04-07

    Heat stress in glass industry is mainly studied in large and highly mechanized manufacturing Units. To the contrary, few studies were carried out in small factories specialized in hand-made products. To stress the need of combined objective and medical surveys in these environments, this paper deals with a simultaneous climatic and physiological investigation of working conditions in artistic crystal glass factories in Tuscany (Italy). The microclimatic monitoring, through a continuous survey has been carried out in early spring. The main physiological parameters (metabolic rate, heart rate, tympanic temperature and water loss) were measured over the whole shifts. The results show that, despite the arduousness of the working conditions, the heat stress levels are physiologically tolerable. The predictions made using the PHS model at the Analysis level described in ISO 15265 agree closely to the observed values, validating the use of PHS model in these conditions. This model was then used to analyse what is likely to be the situation during the summer. It is concluded that the heat constraint will be very high and that some steps must be taken from the spring to monitor closely the exposed workers in the summer and take measures to prevent any heat accident.

  6. 21 CFR 890.5950 - Powered heating unit.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered heating unit. 890.5950 Section 890.5950...) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5950 Powered heating unit. (a) Identification. A powered heating unit is a device intended for medical purposes that...

  7. Heating great residential units with combustion-motor heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Vossen, W

    1982-10-01

    Economic usage of combustion-motor heat pumps requires: reliable technology and delivery of the heat pump; design and operation. The heat pump must be integrated perfectly into the heating system. This contributions is based on a three-year operational experience with over 150 heat pumps used mainly in residential and administrative buildings (plus commercial buildings, swimming pools, sport centres etc.). These are heat pumps operating on the compression principle with natural gas, liquid gas, or fuel oil.

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

    International Nuclear Information System (INIS)

    Militzer, J.; Basu, P.; Adaikkappan, N.

    1985-01-01

    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)

  9. Heat transfer unit and method for prefabricated vessel

    Science.gov (United States)

    Tamburello, David A.; Kesterson, Matthew R; Hardy, Bruce J.

    2017-11-07

    Vessel assemblies, heat transfer units for prefabricated vessels, and methods for heat transfer prefabricated vessel are provided. A heat transfer unit includes a central rod, and a plurality of peripheral rods surrounding the central rod and connected to the central rod. The plurality of peripheral rods are movable between a first collapsed position and a second bowed position, wherein in the second bowed position a midpoint of each of the plurality of peripheral rods is spaced from the central rod relative to in the first position. The heat transfer unit further includes a heat transfer element connected to one of the plurality of peripheral rods.

  10. Computer aided heat transfer analysis in a laboratory scaled heat exchanger unit

    International Nuclear Information System (INIS)

    Gunes, M.

    1998-01-01

    In this study. an explanation of a laboratory scaled heat exchanger unit and a software which is developed to analyze heat transfer. especially to use it in heat transfer courses, are represented. Analyses carried out in the software through sample values measured in the heat exchanger are: (l) Determination of heat transfer rate, logarithmic mean temperature difference and overall heat transfer coefficient; (2)Determination of convection heat transfer coefficient inside and outside the tube and the effect of fluid velocity on these; (3)Investigation of the relationship between Nusselt Number. Reynolds Number and Prandtl Number by using multiple non-linear regression analysis. Results are displayed on the screen graphically

  11. Consumer Unit for Low Energy District Heating Net

    DEFF Research Database (Denmark)

    Paulsen, Otto; Fan, Jianhua; Furbo, Simon

    2008-01-01

    to reduce heat loss in the network. The consumer’s installation is a unit type with an accumulation tank for smoothing the heat load related to the domestic hot water. The building heat load is delivered by an under-floor heating system. The heavy under-floor heating system is assumed to smooth the room...... heat load on a daily basis, having a flow temperature control based on outdoor climate. The unit is designed for a near constant district heating water flow. The paper describes two concepts. The analyses are based on TRNSYS (Klein et al., 2006) simulation, supplied with laboratory verification......A low energy/ low temperature consumer installation is designed and analyzed. The consumer type is a low energy single family house 145 m2 with annual energy consumption in the range of 7000 kWh, incl. domestic hot water in a 2800 degree day climate. The network is an extreme low temperature system...

  12. The role of heat pipes in intensified unit operations

    International Nuclear Information System (INIS)

    Reay, David; Harvey, Adam

    2013-01-01

    Heat pipes are heat transfer devices that rely, most commonly, on the evaporation and condensation of a working fluid contained within them, with passive pumping of the condensate back to the evaporator. They are sometimes referred to as ‘thermal superconductors’ because of their exceptionally high effective thermal conductivity (substantially higher than any metal). This, together with several other characteristics make them attractive to a range of intensified unit operations, particularly reactors. The majority of modern computers deploy heat pipes for cooling of the CPU. The application areas of heat pipes come within a number of broad groups, each of which describes a property of the heat pipe. The ones particularly relevant to chemical reactors are: i. Separation of heat source and sink. ii. Temperature flattening, or isothermalisation. iii. Temperature control. Chemical reactors, as a heat pipe application area, highlight the benefits of the heat pipe based on isothermalisation/temperature flattening device and on being a highly effective heat transfer unit. Temperature control, done passively, is also of relevance. Heat pipe technology offers a number of potential benefits to reactor performance and operation. The aim of increased yield of high purity, high added value chemicals means less waste and higher profitability. Other intensified unit operations, such as those employing sorption processes, can also profit from heat pipe technology. This paper describes several variants of heat pipe and the opportunities for their use in intensified plant, and will give some current examples. -- Highlights: ► Heat pipes – thermal superconductors – can lead to improved chemical reactor performance. ► Isothermalisation within a reactor vessel is an ideal application. ► The variable conductance heat pipe can control reaction temperatures within close limits. ► Heat pipes can be beneficial in intensified reactors

  13. Low Temperature District Heating Consumer Unit with Micro Heat Pump for Domestic Hot Water Preparation

    DEFF Research Database (Denmark)

    Zvingilaite, Erika; Ommen, Torben Schmidt; Elmegaard, Brian

    2012-01-01

    In this paper we present and analyse the feasibility of a district heating (DH) consumer unit with micro heat pump for domestic hot water (DHW) preparation in a low temperature (40 °C) DH network. We propose a micro booster heat pump of high efficiency (COP equal to 5,3) in a consumer DH unit...... in order to boost the temperature of the district heating water for heating the DHW. The paper presents the main designs of the suggested system and different alternative micro booster heat pump concepts. Energy efficiency and thermodynamic performance of these concepts are calculated and compared....... The results show that the proposed system has the highest efficiency. Furthermore, we compare thermodynamic and economic performance of the suggested heat pump-based concept with different solutions, using electric water heater. The micro booster heat pump system has the highest annualised investment (390 EUR...

  14. Manufacturing A Refrigerator with Heat Recovery Unit

    Directory of Open Access Journals (Sweden)

    Mustafa Mohammed Kadhim

    2018-02-01

    Full Text Available This study aims to exploite the rejected heating energy from condenser and benefit from it to reheat the foods and other materials. It can also be employed to improve the coefficient of performance of a refrigerator at the same time by using approximately the same consumption electrical energy used to operate the compressor and refrigerator in general. This idea has been implemented by manufacturing of a refrigerator with using additional part has the same metal and condenser pipe diameters but its surface area does not exceed 40% from total surface area of the condenser and its design as an insulated cabinet from all sides to prevent heat leakage through it and located between the compressor and the condenser. Small electrical fan has been added inside this cabinet to provide a suitable air circulation and a homogenous temperature distribution inside the cabinet space. It is expected that the super heating energy of refrigerant (R134a which comes out of the compressor would be removed  inside this cabinet and this insist to condensate the refrigerant (cooling fluid with a rate higher than that used in the normal refrigerator only. Three magnetic valves have been used in order to control the refrigerant flow in state of operation the refrigerator only or to gather with heating cabinet. To measure the temperatures at each process of the simple vapor compression refrigeration cycle, nine temperature sensors at input and output of each compressor, condenser and an evaporator in additional to input of cabinet and inside it and on evaporator surface have been provided. Five pressure gages have been used to measure the value of pressure and compare it for the two states of operation. The consumption of electrical energy  can be calculated by adding an ammeter and a voltmeter and compare between the consumption energy of both states. The obtained results show that there is an improvement in the coeffecient of performance in state of operation the

  15. Heating unit of Berovo by co-generation (Macedonia)

    International Nuclear Information System (INIS)

    Armenski, Slave; Dimitrov, Konstantin; Tashevski, Done

    1999-01-01

    A plant for combined heat and electric power production, for central heating of the town Berovo (Macedonia) is proposed. The common reason to use a co-generation unit is the energy efficiency and a significant reduction of environmental pollution. The heat consumption of town Berovo is analyzed and determined. Based on the energy consumption of a whole power plant, e. i. the plant for combined and simultaneous production of power is proposed. The quantity of annually heat and electrical production and annually coal consumption are estimated. (Author)

  16. Energetic and Exergy Efficiency of a Heat Storage Unit for Building Heating

    International Nuclear Information System (INIS)

    Hazami, Mejdi; Kooli, Sami; Lazaar, Meriem; Farhat, Abdelhamid; Belghith, Ali

    2009-01-01

    This paper deals with a numerical and experimental investigation of a daily solar storage system conceived and built in Laboratoire de Maitrise des Technologies de l Energie (LMTE, Borj Cedria). This system consists mainly of the storage unit connected to a solar collector unit. The storage unit consists of a wooden case with dimension of 5 m 3 (5 m x 1m x 1m) filed with fin sand. Inside the wooden case was buried a network of a polypropylene capillary heat exchanger with an aperture area equal to 5 m 2 . The heat collection unit consisted of 5 m 2 of south-facing solar collector mounted at a 37 degree tilt angle. In order to evaluate the system efficiency during the charging period (during the day) and discharging period (during the night) an energy and exergy analyses were applied. Outdoor experiments were also carried out under varied environmental conditions for several consecutive days. Results showed that during the charging period, the average daily rates of thermal energy and exergy stored in the heat storage unit were 400 and 2.6 W, respectively. It was found that the net energy and exergy efficiencies in the charging period were 32 pour cent and 22 pour cent, respectively. During the discharging period, the average daily rates of the thermal energy and exergy recovered from the heat storage unit were 2 kW and 2.5 kW, respectively. The recovered heat from the heat storage unit was used for the air-heating of a tested room (4 m x 3 m x 3 m). The results showed that 30 pour cent of the total heating requirement of the tested room was obtained from the heat storage system during the whole night in cold seasons

  17. Outdoor unit construction for an electric heat pump

    Science.gov (United States)

    Draper, R.; Lackey, R.S.

    1984-09-11

    The outdoor unit for an electric heat pump is provided with an upper portion containing propeller fan means for drawing air through the lower portion containing refrigerant coil means in the form of four discrete coils connected together in a subassembly forming a W shape, the unit being provided with four adjustable legs which are retracted in shipment, and are adjusted on site to elevate the unit to a particular height suitable for the particular location in which the unit is installed. 4 figs.

  18. A New Approach for Heating the Plastics Injection Units

    Directory of Open Access Journals (Sweden)

    Virgilius Vasilache

    2010-06-01

    Full Text Available The plastics injection molding machines are one of the most eager consumers of energy. The plasticizing unit itself is the most important energetic consumer among the subassemblies of these machines; that is why this subassembly is the target of most actions of consumption decreasing on such machines. Our concerns on this direction got the shape of developing a new heating system for the plasticizing unit, which system was already patented [1].

  19. The urban heat island dynamics during heat waves: a study of cities in the United States

    Science.gov (United States)

    Hu, Leiqiu

    2016-04-01

    The urban heat island (UHI) is a common phenomenon describing that metropolitan areas are usually warmer than their rural surroundings. This effect is compounded by extreme heat events, which are a leading cause of weather-related human mortality in many countries worldwide. However, the spatial and diurnal variability of temperature and humidity in urban and adjacent rural areas during extreme heat events is not well measured and therefore not well understood. The recently developed dataset of near-surface air and dew temperature from MODIS atmospheric profiles and the new method for the UHI quantification--urban heat island curve are used to quantify the urban climatic changes during heat waves in cities of the United States. The enhanced and weakened UHIs are observed in various cities. The causes of UHI changes during heat waves are discussed, including climate region, vegetation type and amount, city geolocation, etc.

  20. Sustainability assessment of heat exchanger units for spray dryers

    International Nuclear Information System (INIS)

    Caglayan, Hasan; Caliskan, Hakan

    2017-01-01

    In this study, the sustainability assessment is performed to the system known as heat exchanger unit with spray dryer. The five-different dead state temperatures (0-5-10-15-20 °C) are considered. It is found that the heat exchanger has the highest energy efficiency (63.32%), while the overall system has the lowest one (5.56%). So, the combination of the spray dryer with the heat exchanger is more effective. On the other hand, the overall exergy efficiency of the system is lower than the heat exchanger and spray dryer for all of the dead state (environmental) temperatures. The exergy efficiency of the heat exchanger is inversely proportional to the dead state temperature, and the maximum rate is found as 49.65% at 0 °C. Furthermore, the exergy efficiencies of the spray dryer and overall system are directly proportional to the dead state temperatures, and the corresponding maximum rates are found to be 26.41% and 24.32% at 20 °C, respectively. Also, the exergy destruction is directly proportional to the dead state temperatures. The minimum and maximum exergy destruction rates are found at the dead state temperatures of 0 °C and 20 °C, respectively. Furthermore, the most sustainable system is found as the heat exchanger unit. - Highlights: • Thermodynamic analyses of industrial heat exchangers and spray dryers. • Sustainability of heat exchangers for spray dryers. • Dead state temperature effects on exergy efficiencies of heat exchangers and spray dryers.

  1. Airflow and Heat Transfer in the Slot-Vented Room with Radiant Floor Heating Unit

    Directory of Open Access Journals (Sweden)

    Xiang-Long Liu

    2012-01-01

    Full Text Available Radiant floor heating has received increasing attention due to its diverse advantages, especially the energy saving as compared to the conventional dwelling heating system. This paper presents a numerical investigation of airflow and heat transfer in the slot-vented room with the radiant floor heating unit. Combination of fluid convection and thermal radiation has been implemented through the thermal boundary conditions. Spatial distributions of indoor air temperature and velocity, as well as the heat transfer rates along the radiant floor and the outer wall, have been presented and analyzed covering the domains from complete natural convection to forced convection dominated flows. The numerical results demonstrate that the levels of average temperature in the room with lateral slot-ventilation are higher than those without slot-ventilation, but lower than those in the room with ceiling slot-ventilation. Overall, the slot-ventilation room with radiant floor heating unit could offer better indoor air quality through increasing the indoor air temperature and fresh air exchanging rate simultaneously. Concerning the airborne pollutant transports and moisture condensations, the performance of radiant floor heating unit will be further optimized in our future researches.

  2. Empirical Analysis for the Heat Exchange Effectiveness of a Thermoelectric Liquid Cooling and Heating Unit

    Directory of Open Access Journals (Sweden)

    Hansol Lim

    2018-03-01

    Full Text Available This study aims to estimate the performance of thermoelectric module (TEM heat pump for simultaneous liquid cooling and heating and propose empirical models for predicting the heat exchange effectiveness. The experiments were conducted to investigate and collect the performance data of TEM heat pump where the working fluid was water. A total of 57 sets of experimental data were statistically analyzed to estimate the effects of each independent variable on the heat exchange effectiveness using analysis of variance (ANOVA. To develop the empirical model, the six design parameters were measured: the number of transfer units (NTU of the heat exchangers (i.e., water blocks, the inlet water temperatures and temperatures of water blocks at the cold and hot sides of the TEM. As a result, two polynomial equations predicting heat exchange effectiveness at the cold and hot sides of the TEM heat pump were derived as a function of the six selected design parameters. Also, the proposed models and theoretical model of conventional condenser and evaporator for heat exchange effectiveness were compared with the additional measurement data to validate the reliability of the proposed models. Consequently, two conclusions have been made: (1 the possibility of using the TEM heat pump for simultaneous cooling and heating was examined with the maximum temperature difference of 30 °C between cold and hot side of TEM, and (2 it is revealed that TEM heat pump has difference with the conventional evaporator and condenser from the comparison results between the proposed models and theoretical model due to the heat conduction and Joule effect in TEM.

  3. Characterization of heat emission of light-curing units.

    Science.gov (United States)

    Wahbi, Mohammed A; Aalam, F A; Fatiny, F I; Radwan, S A; Eshan, I Y; Al-Samadani, K H

    2012-04-01

    This study was designed to analyze the heat emissions produced by light-curing units (LCUs) of different intensities during their operation. The null hypothesis was that the tested LCUs would show no differences in their temperature rises. FIVE COMMERCIALLY AVAILABLE LCUS WERE TESTED: a "Flipo" plasma arc, "Cromalux 100" quartz-tungsten-halogen, "L.E. Demetron 1" second-generation light-emitting diode (LED), and "Blue Phase C5" and "UltraLume 5" third-generation LED LCUs. The intensity of each LCU was measured with two radiometers. The temperature rise due to illumination was registered with a type-K thermocouple, which was connected to a computer-based data acquisition system. Temperature changes were recorded in continues 10 and 20 s intervals up to 300 s. The Flipo (ARC) light source revealed the highest mean heat emission while the L.E. Demetron 1 LED showing the lowest mean value at 10 and 20 s exposure times. Moreover, Cromalux (QTH) recorded the second highest value for all intervals (12.71, 14.63, 14.60) of heat emission than Blue Phase C5 (LED) (12.25, 13.87, 13.69), interestingly at 20 s illumination for all intervals the highest results (18.15, 19.27, 20.31) were also recorded with Flipo (PAC) LCU, and the lowest (6.71, 5.97, 5.55) with L.E. Demetron 1 LED, while Blue Phase C5 (LED) recorded the second highest value at the 1st and 2nd 20 s intervals (14.12, 11.84, 10.18) of heat emission than Cromalux (QTH) (12.26, 11.43, 10.26). The speed of temperature or heat rise during the 10 and 20 s depends on light intensity of emitted light. However, the QTH LCU was investigated resulted in a higher temperature rise than LED curing units of the same power density. The PAC curing unit induced a significantly higher heat emission and temperature increase in all periods, and data were statistically different than the other tested groups (p < .05). LED (Blue Phase C5) was not statistically significant (p < .05) (at 10 s) than QTH units, also LED (Blue

  4. A heated vapor cell unit for DAVLL in atomic rubidium

    OpenAIRE

    McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

    2007-01-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm-long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field...

  5. Heat recovery unit operation of HVAC system in IMEF

    International Nuclear Information System (INIS)

    Paek, S. R.; Oh, Y. W.; Song, E. S.; Park, D. K.; Joo, Y. S.; Hong, K. P.

    2003-01-01

    HVAC system including a supply and exhaust air system in IMEF(Irradiated Materials Examination Facility) is an essential facility for preventing a leakage of radioactive materials and for a preservation of a working environment. It costs a lot to operate the HVAC system in IMEF because our ventilation type is once-through system, and an air flow is maintained from low level contamination area to high level and maintained high turns of ventilation air under certain conditions. As HRU(Heat Recovery Unit) at HVAC system based on PIEF(Post Irradiation Examination Facility) operation experiences is designed and adopted, it prevents from a heating coil freezing destruction in winter and makes much energy saving etc.. Heat pipe type HRU is adopted in IMEF, and a construction and operation result of HRU is examined

  6. HEAT ENGINEERING TESTING OF AIR COOLING UNIT OF HORIZONTAL TYPE

    OpenAIRE

    Rohachov, Valerii Andriiovych; Semeniako, Oleksandr Volodymyrovych; Лазоренко, Р. О.; Середа, Р. М.; Parafeinyk, Volodymyr Petrovych

    2018-01-01

    The results of the thermal tests of the section of air cooler, the heat-exchange surface of which is made up of chess package of bimetal finned tubes are presented. The methods of research are presented, the experimental stand is described, the measurement errors are given. The efficiency of the experimental stand and the accuracy of the experimental data on it are confirmed. Proposed to use the stand for researches of air cooling units with other types and sections of finned tubes.

  7. Comparison of the heat generation of light curing units.

    Science.gov (United States)

    Bagis, Bora; Bagis, Yildirim; Ertas, Ertan; Ustaomer, Seda

    2008-02-01

    The aim of this study was to evaluate the heat generation of three different types of light curing units. Temperature increases were recorded from a distance of 1 mm from a thermocouple to the tip of three different types of light curing units including one quartz-tungsten halogen (QTH), one plasma arc (PAC), and one light emitting diode (LED) unit. An experimental model was designed to fix the 1 mm distance between the tip of the light curing units and the thermocouple wire. Temperature changes were recorded in 10 second intervals up to 40 seconds. (10, 20, 30, and 40 seconds). Temperature measurements were repeated three times for every light curing unit after a one hour standby period. Statistical analysis of the results was performed using the analysis of variance (ANOVA) and the Bonferroni Test. The highest temperature rises (54.4+/-1.65 degrees C) occurred during activation of a PAC light curing unit for every test period (pdamage to the pulp.

  8. Possibility of using adsorption refrigeration unit in district heating network

    Science.gov (United States)

    Grzebielec, Andrzej; Rusowicz, Artur; Jaworski, Maciej; Laskowski, Rafał

    2015-09-01

    Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

  9. Linking Excessive Heat with Daily Heat-Related Mortality over the Coterminous United States

    Science.gov (United States)

    Quattrochi, Dale A.; Crosson, William L.; Al-Hamdan, Mohammad Z.; Estes, Maurice G., Jr.

    2014-01-01

    In the United States, extreme heat is the most deadly weather-related hazard. In the face of a warming climate and urbanization, which contributes to local-scale urban heat islands, it is very likely that extreme heat events (EHEs) will become more common and more severe in the U.S. This research seeks to provide historical and future measures of climate-driven extreme heat events to enable assessments of the impacts of heat on public health over the coterminous U.S. We use atmospheric temperature and humidity information from meteorological reanalysis and from Global Climate Models (GCMs) to provide data on past and future heat events. The focus of research is on providing assessments of the magnitude, frequency and geographic distribution of extreme heat in the U.S. to facilitate public health studies. In our approach, long-term climate change is captured with GCM outputs, and the temporal and spatial characteristics of short-term extremes are represented by the reanalysis data. Two future time horizons for 2040 and 2090 are compared to the recent past period of 1981- 2000. We characterize regional-scale temperature and humidity conditions using GCM outputs for two climate change scenarios (A2 and A1B) defined in the Special Report on Emissions Scenarios (SRES). For each future period, 20 years of multi-model GCM outputs are analyzed to develop a 'heat stress climatology' based on statistics of extreme heat indicators. Differences between the two future and the past period are used to define temperature and humidity changes on a monthly time scale and regional spatial scale. These changes are combined with the historical meteorological data, which is hourly and at a spatial scale (12 km) much finer than that of GCMs, to create future climate realizations. From these realizations, we compute the daily heat stress measures and related spatially-specific climatological fields, such as the mean annual number of days above certain thresholds of maximum and minimum air

  10. Possibility of using adsorption refrigeration unit in district heating network

    Directory of Open Access Journals (Sweden)

    Grzebielec Andrzej

    2015-09-01

    Full Text Available Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

  11. Computational model and performance optimization methodology of a compact design heat exchanger used as an IHX in HTGR

    International Nuclear Information System (INIS)

    De la Torre V, R.; Francois L, J. L.

    2017-09-01

    The intermediate heat exchangers (IHX) present in high-temperature gas-cooled reactor (HTGR) present complex operating conditions, characterized by temperature values higher than 1073 K. Conventional designs of tubes and shell have shown disadvantages with respect to compact designs. In this work, computational models of a compact heat exchanger design, the printed circuit, were built under IHX conditions in a HTGR installation. In these models, a detailed geometry was considered in three dimensions, corresponding to a transfer unit of the heat exchanger. Computational fluid dynamics techniques and finite element methods were used to study the thermo-hydraulic and mechanical functioning of the equipment, respectively. The properties of the materials were defined as temperature functions. The thermo-hydraulic results obtained were established as operating conditions in the structural calculations. A methodology was developed based on the analysis of capital and operating costs, which takes into account the heat transfer, pressure drop and the mechanical behavior of the structure, in a single optimization variable. By analyzing the experimental results of other authors, a relationship was obtained between the operation time of the equipment and the maximum effort in the structure, which was used in the model. The results show that the model that allows a greater thermal efficiency differs from the one that has lower total cost per year. (Author)

  12. Experimental investigations on cylindrical latent heat storage units with sodium acetate trihydrate composites utilizing supercooling

    DEFF Research Database (Denmark)

    Dannemand, Mark; Johansen, Jakob Berg; Kong, Weiqiang

    2016-01-01

    Latent heat storage units utilizing stable supercooling of sodium acetate trihydrate (SAT) composites were tested in a laboratory. The stainless steel units were 1.5 m high cylinders with internal heat exchangers of tubes with fins. One unit was tested with 116 kg SAT with 6% extra water. Another...... in the thickened phase change material after melting. The heat content in the fully charged state and the heat released after solidification of the supercooled SAT mixtures at ambient temperature was higher for the unit with the thickened SAT mixture. The heat discharged after solidification of the supercooled SAT...

  13. Design and operation of gas-heated thermal pumping units

    Energy Technology Data Exchange (ETDEWEB)

    Rostek, H A [Ruhrgas A.G., Essen (Germany, F.R.)

    1979-03-01

    The first gas heat pump systems have been operated since spring 1977. These are applied in living houses, school, swimming pools, and sport places and administration buildings. The heating performance of these systems is 150-3800 kW. Two of these systems, one in a swimming pool and one in a house for several families are operating, each of them for one heating period. The operational experiences with these gas heat pumps are reported on, basing on measurement results. The experience gathered from the operation of gas heat pumps systems is applied to the planning of other plants. The development of a standardized gas heat pump-series is emphasized.

  14. 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

    A laboratory experimental study was conducted to investigate the energy performance of a total heat recovery unit using a polymer membranes heat exchanger. The study was conducted in twin climate chambers. One of the chambers simulated outdoor climate conditions and the other simulated the climate...... 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 the measured temperature and humidity values, the temperature, humidity, and enthalpy efficiencies of the total heat recovery unit were calculated. The experiment was conducted in different combinations of outdoor climate conditions simulating warm and humid outdoor climates and air-conditioned indoor climate...

  15. Analysis and Choice of Optimal Heating Ventilation Air Conditioning System for a Teaching Unit

    Directory of Open Access Journals (Sweden)

    Marina Verdeş

    2007-01-01

    Full Text Available Under the conditions of present society in which providing an optimum interior comfort is confronted with the necessity of the energy consumption reduction, solving this problem depends on the factors which contribute to the achievements of this comfort. Modern buildings -- implicitly teaching unit -- may be equipped with installations which have low energy consumption, respective a heating, cooling and ventilating integrated system with heat pumps system which can assure all the required comfort conditions. This paper underlines the necessity to use the heat pump in heating system for a teaching unit, energetic and economic guides and the possibility to increase them when using cooling and heating mixed. The solution of heat pumps for heating of the teaching unit and the energetic and economic advantages of the system is made in study.

  16. Electric heating of a unit for uranium trioxide production

    International Nuclear Information System (INIS)

    Faron, R.; Striff, A.

    1985-01-01

    Ammonium diuranate U 2 O 7 (NH 4 ) 2 containing about 50% of water is dried and transformed by calcination in uranium trioxide UO 3 . Drying and calcination was obtained by air heated by two burners using domestic fuel. In 1984 the plant was transformed for utilization of electric heating improving maintenance cost, decreasing heat losses and by energy saving the payback period on investment is of 2.6 years [fr

  17. Developing maintenance technologies for FBR's heat exchanger units by advanced laser processing

    International Nuclear Information System (INIS)

    Nishimura, Akihiko; Shimada, Yukihiro

    2011-01-01

    Laser processing technologies were developed for the purpose of maintenance of FBR's heat exchanger units. Ultrashort laser processing fabricated fiber Bragg grating sensor for seismic monitoring. Fiber laser welding with a newly developed robot system repair cracks on inner wall of heat exchanger tubes. Safety operation of the heat exchanger units will be improved by the advanced laser processing technologies. These technologies are expected to be applied to the maintenance for the next generation FBRs. (author)

  18. Alternative Procedure of Heat Integration Tehnique Election between Two Unit Processes to Improve Energy Saving

    Science.gov (United States)

    Santi, S. S.; Renanto; Altway, A.

    2018-01-01

    The energy use system in a production process, in this case heat exchangers networks (HENs), is one element that plays a role in the smoothness and sustainability of the industry itself. Optimizing Heat Exchanger Networks (HENs) from process streams can have a major effect on the economic value of an industry as a whole. So the solving of design problems with heat integration becomes an important requirement. In a plant, heat integration can be carried out internally or in combination between process units. However, steps in the determination of suitable heat integration techniques require long calculations and require a long time. In this paper, we propose an alternative step in determining heat integration technique by investigating 6 hypothetical units using Pinch Analysis approach with objective function energy target and total annual cost target. The six hypothetical units consist of units A, B, C, D, E, and F, where each unit has the location of different process streams to the temperature pinch. The result is a potential heat integration (ΔH’) formula that can trim conventional steps from 7 steps to just 3 steps. While the determination of the preferred heat integration technique is to calculate the potential of heat integration (ΔH’) between the hypothetical process units. Completion of calculation using matlab language programming.

  19. Computational model and performance optimization methodology of a compact design heat exchanger used as an IHX in HTGR; Modelo computacional y metodologia de optimizacion del funcionamiento de un intercambiador de calor de diseno compacto empleado como IHX en HTGR

    Energy Technology Data Exchange (ETDEWEB)

    De la Torre V, R.; Francois L, J. L., E-mail: delatorrevaldes@gmail.com [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Ciudad Universitaria, Circuito Exterior s/n, 04510 Ciudad de Mexico (Mexico)

    2017-09-15

    The intermediate heat exchangers (IHX) present in high-temperature gas-cooled reactor (HTGR) present complex operating conditions, characterized by temperature values higher than 1073 K. Conventional designs of tubes and shell have shown disadvantages with respect to compact designs. In this work, computational models of a compact heat exchanger design, the printed circuit, were built under IHX conditions in a HTGR installation. In these models, a detailed geometry was considered in three dimensions, corresponding to a transfer unit of the heat exchanger. Computational fluid dynamics techniques and finite element methods were used to study the thermo-hydraulic and mechanical functioning of the equipment, respectively. The properties of the materials were defined as temperature functions. The thermo-hydraulic results obtained were established as operating conditions in the structural calculations. A methodology was developed based on the analysis of capital and operating costs, which takes into account the heat transfer, pressure drop and the mechanical behavior of the structure, in a single optimization variable. By analyzing the experimental results of other authors, a relationship was obtained between the operation time of the equipment and the maximum effort in the structure, which was used in the model. The results show that the model that allows a greater thermal efficiency differs from the one that has lower total cost per year. (Author)

  20. Cold and heat waves in the United States.

    Science.gov (United States)

    Barnett, A G; Hajat, S; Gasparrini, A; Rocklöv, J

    2012-01-01

    Extreme cold and heat waves, characterized by a number of cold or hot days in succession, place a strain on people's cardiovascular and respiratory systems. The increase in deaths due to these waves may be greater than that predicted by extreme temperatures alone. We examined cold and heat waves in 99 US cities for 14 years (1987-2000) and investigated how the risk of death depended on the temperature threshold used to define a wave, and a wave's timing, duration and intensity. We defined cold and heat waves using temperatures above and below cold and heat thresholds for two or more days. We tried five cold thresholds using the first to fifth percentiles of temperature, and five heat thresholds using the 95-99 percentiles. The extra wave effects were estimated using a two-stage model to ensure that their effects were estimated after removing the general effects of temperature. The increases in deaths associated with cold waves were generally small and not statistically significant, and there was even evidence of a decreased risk during the coldest waves. Heat waves generally increased the risk of death, particularly for the hottest heat threshold. Cold waves of a colder intensity or longer duration were not more dangerous. Cold waves earlier in the cool season were more dangerous, as were heat waves earlier in the warm season. In general there was no increased risk of death during cold waves above the known increased risk associated with cold temperatures. Cold or heat waves earlier in the cool or warm season may be more dangerous because of a build up in the susceptible pool or a lack of preparedness for extreme temperatures. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Analysis of Thermal Design of Heating Units with Meteorological Climate Peculiarities

    Science.gov (United States)

    Seminenko, A. S.; Elistratova, Y. V.; Pererva, M. I.; Moiseev, M. V.

    2018-03-01

    This article is devoted to the analysis of thermal design of heating units, one of the compulsory calculations of heating systems, which ensures their stable and efficient operation. The article analyses the option of a single-pipe heating system with shifted end-capping areas and the overhead supply main; the difference is shown in the calculation results between heat balance equation of the heating unit and calculation of the actual heat flux (heat transfer coefficient) taking into account deviation from the standardized (technical passport) operating conditions. The calculation of the thermal conditions of residential premises is given, the deviation of the internal air temperature is shown taking into account the discrepancy between the calculation results for thermal energy.

  2. Experimental investigations on cylindrical latent heat storage units with sodium acetate trihydrate composites utilizing supercooling

    DEFF Research Database (Denmark)

    Dannemand, Mark; Johansen, Jakob Berg; Kong, Weiqiang

    2016-01-01

    unit was tested with 116.3 kg SAT with 0.5% Xanthan rubber as a thickening agent and 4.4% graphite powder. The heat exchange capacity rate during charge was significantly lower for the unit with SAT and Xanthan rubber compared to the unit with SAT and extra water. This was due to less convection...

  3. Experimental investigations on prototype heat storage units utilizing stable supercooling of sodium acetate trihydrate mixtures

    DEFF Research Database (Denmark)

    Dannemand, Mark; Dragsted, Janne; Fan, Jianhua

    2016-01-01

    Laboratory tests of two heat storage units based on the principle of stable supercooling of sodium acetate trihydrate (SAT) mixtures were carried out. One unit was filled with 199.5 kg of SAT with 9% extra water to avoid phase separation of the incongruently melting salt hydrate. The other unit...

  4. Simulation of a passive house coupled with a heat pump/organic Rankine cycle reversible unit

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Randaxhe, François

    2014-01-01

    This paper presents a dynamic model of a passive house located in Denmark with a large solar absorber, a horizontal ground heat exchanger coupled with a HP/ORC unit. The HP/ORC reversible unit is a module able to work as an Organic Rankine Cycle (ORC) or as a heat pump (HP). There are 3 possible ...... presents a higher global COP because the heat produced on the roof can heat the storage directly.......This paper presents a dynamic model of a passive house located in Denmark with a large solar absorber, a horizontal ground heat exchanger coupled with a HP/ORC unit. The HP/ORC reversible unit is a module able to work as an Organic Rankine Cycle (ORC) or as a heat pump (HP). There are 3 possible...... modes that need to be chosen optimally depending on the weather conditions, the heat demand and the temperature level of the storage. The ORC mode is activated, as long as the heat demand of the house is covered by the storage to produce electricity based upon the heat generated by the solar roof...

  5. An application of the gas-fired chilling and heating units to domestic houses

    Energy Technology Data Exchange (ETDEWEB)

    Choi, J.H.; Yang, Y.M.; Chae, J.M.; Bang, H.S.; Kwon, O.B.; Yoo, S.I.; Kim, T.H. [R and D Center, Korea Gas Co. (Korea); Lee, T.W.; Kim, T.H.; Kim, B.H.; Hwang, I.J.; Kim, J.Y.; Kim, C.D.; Park, S.J. [Korea Institute of Construction Technology (Korea)

    1999-10-01

    Following researches and considerations were performed in this study for an efficient application of gas-fired chilling and heating units to the residential buildings. (1) Status of domestic cooling and heating for residential building. (2) Various introduction schemes of outdoor unit. (3) Design exclusive area for the gas appliance and installation of it. (4) Ventilation of exhaust gas and heat. (5) Prepare the installation specifications or standards for gas-fired chilling and heating units. (6) Design technique of plumbing for cooling and heating. (7) Evaluation of unit's capacity considering the thermal load of domestic buildings. (8) Cooling and heating system with the unit. (9) Fundamental test for evaluation of applicability. (10) Actual design and construction of experimental house for an application and a demonstration of the developed gas units. (11) Field test for cooling and heating. (12) Evaluation of economic efficiency. (13) Establish a business potential. (14) Establishment of legal and systematic support, energy rate. (15) Troubleshooting in the course of development and application of the new gas appliance. 41 refs., 214 figs., 52 tabs.

  6. Integrating Solar Heating into an Air Handling Unit to Minimize Energy Consumption

    OpenAIRE

    Wilson, Scott A

    2010-01-01

    The purpose of this project was to test a method of integrating solar heating with a small commercial air handling unit (AHU). In order to accomplish this a heat exchanger was placed in the reheat position of the AHU and piped to the solar heating system. This heat exchanger is used to supplement or replace the existing electric reheat. This method was chosen for its ability to utilize solar energy on a more year round basis when compared to a traditional heating system. It allows solar h...

  7. Performance investigation on a multi-unit heat pump for simultaneous temperature and humidity control

    International Nuclear Information System (INIS)

    Fan, Hongming; Shao, Shuangquan; Tian, Changqing

    2014-01-01

    Highlights: • A multi-unit heat pump is proposed for simultaneous temperature and humidity control. • Condensation heat is non, partly or fully recovered for temperature regulation. • Highly integrated heat pump for residential cooling, dehumidification and heating. • High energy saving potential for all-year-round operation in wet and warm regions. - Abstract: A multi-unit heat pump is presented for simultaneous humidity and temperature control to improve the energy efficiency and the thermal comfort. Two parallel connected condensers are employed in the system, locating at the back of the indoor evaporator and the outdoor unit, respectively. The heat pump can operate in four modes, including heating, cooling and dehumidification without and/or with partial or total condensing heat recovery. The experimental investigation shows that the temperature control capacity is from 3.5 kW for cooling to 3.8 kW for heating with the cooling and heating efficiency higher than 3.5 kW kW −1 , and the dehumidification rate is about 2.0 kg h −1 with the efficiency about 2.0 kg h −1 kW −1 . The supply air temperature and humidity can be simultaneously regulated with high accuracy and high efficiency by adjusting the indoor and/or outdoor air volumes. It provides an integrated and effective solution for simultaneous indoor air temperature and humidity control for all-year-round operation in residential buildings

  8. 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.

  9. Evaluation of heat stress in dry cleaner units:A case study in Qom, Iran

    Directory of Open Access Journals (Sweden)

    Javad Malakouti

    2016-04-01

    Full Text Available Background & Aims of the Study: Nowadays, heat stress is one of the most harmful physical agents in workplaces. According to the consequences of heat stress and have no information about it in Qom dry cleaner units, Iran, this study have been designed to evaluate the heat stress among workers of dry cleaner units in Qom province of Iran, in Jul-Aug 2011. Materials & Methods: This cross-sectional study was conducted in 113 units of active dry cleaner units. WBGT (Wet Bulb Globe Temperature index was selected for heat stress evaluation. In order to measure the requisite parameters, WBGT meter made of Casella Company had been used according to ISO 7243. Data had been analyzed according to Occupational Exposure Limits (OELs with SPSS V.16, using analysis of variance, independent T and LSD tests. Results: The average of WBGT index in Qom dry cleaner units of Iran were 28.98±1.64 °C. The average of WBGT index in 66.4% of units was up to 28°C. The average of relative humidity was 42.86%, the average of wet bulb temperature and globe temperature were 25.56°C and 36.72°C, respectively. The findings showed a significant correlation between the average of WBGT index and the standard recommendation level (p<0.0001. In dry cleaner units with less than 10 m2 area, heat stress was higher than other units  significantly (p<0.05. Conclusions: Heat stress in many dry cleaner units in Qom, Iran, was more than recommended OELs. Because of wet bulb and globe temperature in units were high value, the most important measures to heat controls, are technical engineering controls such as  radiation shield, insulation on boilers and modify the cooling systems.

  10. Nuclear safety inspection in treatment process for SG heat exchange tubes deficiency of unit 1, TNPS

    International Nuclear Information System (INIS)

    Zhang Chunming; Song Chenxiu; Zhao Pengyu; Hou Wei

    2006-01-01

    This paper describes treatment process for SG heat exchange tubes deficiency of Unit 1, TNPS, nuclear safety inspection of Northern Regional Office during treatment process for deficiency and further inspection after deficiency had been treated. (authors)

  11. 40 CFR 63.6092 - Are duct burners and waste heat recovery units covered by subpart YYYY?

    Science.gov (United States)

    2010-07-01

    ... Combustion Turbines What This Subpart Covers § 63.6092 Are duct burners and waste heat recovery units covered by subpart YYYY? No, duct burners and waste heat recovery units are considered steam generating units... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Are duct burners and waste heat...

  12. Thermal Efficiency of Cogeneration Units with Multi-Stage Reheating for Russian Municipal Heating Systems

    Directory of Open Access Journals (Sweden)

    Evgeny Lisin

    2016-04-01

    Full Text Available This paper explores the layout of an optimum process for supplying heat to Russian municipal heating systems operating in a market environment. We analyze and compare the standard cogeneration unit design with two-stage reheating of service water coming from controlled extraction locations and layouts that employ three in-line reheaters with heat the supply controlled by a rotary diaphragm and qualitative/quantitative methods (so-called “uncontrolled extraction”. Cogeneration unit designs are benchmarked in terms of their thermal efficiency expressed as a fuel consumption rate. The specific fuel consumption rate on electricity production is viewed as a key parameter of thermal efficiency.

  13. Numerical simulation of the thermal behavior of heat transfer equipment operated at low temperature

    International Nuclear Information System (INIS)

    Pearsica, C.; Zamfirache, M.; Bornea, A.; Gherghinescu, S.

    2003-01-01

    The paper presents a method for calculating the non-steady heat transfer in a shell and tube heat exchanger. The characteristic equations were solved with a Finite Element Method. As the geometry is cylindrical and axial symmetry was assumed, the equations were solved in a two dimensional geometry. The interpolation functions are linear and the Galerkin method was applied. The process occurred without phase change. For the solving of the algebraic equations associated with the differential equations, we used the method of steepest descendent (gradient method). As results, we present the temperature profile for the tube and shell gas. (author)

  14. Flow-induced vibration analysis of heat exchanger and steam generator designs

    International Nuclear Information System (INIS)

    Pettigrew, M.J.; Sylvestre, Y.; Campagna, A.O.

    1977-08-01

    Tube and shell heat exchange components such as steam generators, heat exchangers and condensers are essential parts of CANDU nuclear power stations. Excessive flow-induced vibration may cause tube failures by fatigue or more likely by fretting-wear. Such failures may lead to station shutdowns that are very undesirable in terms of lost production. Hence good performance and reliability dictate a thorough flow-induced vibration analysis at the design stage. This paper presents our approach and techniques in this respect. (author)

  15. Trial production of ceramic heat storage unit and study on thermal properties and thermal characteristics of the heat storage unit. Mixed salts of Na2CO3, MgCl2 and CaCl2 as heat storage medium

    International Nuclear Information System (INIS)

    Shiina, Yasuaki

    1998-12-01

    Heat storage technique of high temperature and high density latent heat can be applied to an accumulator of heat generated by nuclear power plant in the night and to a thermal load absorber. For the practical use of the heat storage technique, it is important to improve heat exchange characteristics between heat storage medium, such as molten salts, and heat transfer fluid because of low thermal conductivity of the molten salts, to improve durability among molten salt and structure materials and to develop the molten salt with stable thermal properties for a long period. Considering the possibility for the improvement of heat exchange characteristics of phase change heat storage system by absorbing molten salt in porous ceramics with high thermal conductivity, high temperature proof and high resistance to corrosion, several samples of the ceramics heat storage unit were made. Basic characteristics of the samples (strength, thermal properties, temperature characteristics during phase change) were measured experimentally and analytically to study the utility and applicability of the samples for the heat storage system. The results show that the heat storage unit should be used in inactive gas condition because water in the air absorbed in the molten salts would yield degeneration of properties and deterioration of strength and that operation temperature should be confined near fusion temperature because some molten salts would be vaporized and mass would be decreased in considerable high temperature. The results also show that when atmospheric temperature changes around the melting temperature, change in ceramic temperature becomes small. This result suggests the possibility that ceramic heat storage unit could be used as thermal load absorber. (J.P.N.)

  16. Large-Scale Combined Heat and Power (CHP) Generation at Loviisa Nuclear Power Plant Unit 3

    International Nuclear Information System (INIS)

    Bergroth, N.

    2010-01-01

    Fortum has applied for a Decision in Principle concerning the construction of a new nuclear power plant unit (Loviisa 3) ranging from 2800-4600 MWth at its site located at the southern coast of Finland. An attractive alternative investigated is a co-generation plant designed for large-scale district heat generation for the Helsinki metropolitan area that is located approximately 75 km west of the site. The starting point is that the district heat generation capacity of 3 unit would be around 1 000 MWth.The possibility of generating district heat for the metropolitan area by Loviisa's two existing nuclear power plant units was investigated back in the 1980s, but it proved unpractical at the time. With the growing concern of the climate change and the subsequent requirements on heat and power generation, the idea is much more attractive today, when recognising its potential to decrease Finland's carbon dioxide emissions significantly. Currently the district heat generation in metropolitan area is based on coal and natural gas, producing some five to seven million tonnes of carbon dioxide emissions annually. Large-scale combined heat and power (CHP) generation at the 3 unit could cut this figure by up to four million tonnes. This would decrease carbon dioxide emissions by as much as six percent. In addition, large-scale CHP generation would increase the overall efficiency of the new unit significantly and hence, reduce the environmental impact on the local marine environment by cutting heat discharges into the Gulf of Nuclear energy has been used for district heating in several countries both in dedicated nuclear heating plants and in CHP generation plants. However, the heat generation capacity is usually rather limited, maximum being around 250 MWth per unit. Set against this, the 3 CHP concept is much more ambitious, not only because of the much larger heat generation output envisaged, but also because the district heating water would have to be transported over a

  17. Thermal performance analysis of a phase change thermal storage unit for space heating

    Energy Technology Data Exchange (ETDEWEB)

    Halawa, E.; Saman, W. [Institute for Sustainable Systems and Technologies School of Advanced Manufacturing and Mechanical Engineering, University of South Australia, Mawson Lakes SA 5095 (Australia)

    2011-01-15

    This paper presents the results of a comprehensive numerical study on the thermal performance of an air based phase change thermal storage unit (TSU) for space heating. The unit is designed for integration into space heating and cooling systems. The unit consists of a number of one dimensional phase change material (PCM) slabs contained in a rectangular duct where air passes between the slabs. The numerical analysis was based on an experimentally validated model. A parametric study has been carried out including the study on the effects of charge and discharge temperature differences, air mass flow rate, slab thicknesses, air gaps and slab dimensions on the air outlet temperatures and heat transfer rates of the thermal storage unit. The paper introduces and discusses quantities called charge and discharge temperature differences which play an important role in the melting and freezing processes. (author)

  18. Organic Rankine cycle unit for waste heat recovery on ships (PilotORC)

    DEFF Research Database (Denmark)

    Haglind, Fredrik; Montagud, Maria E. Mondejar; Andreasen, Jesper Graa

    The project PilotORC was aimed at evaluating the technical and economic feasibility of the use of organic Rankine cycle (ORC) units to recover low-temperature waste heat sources (i.e. exhaust gases, scavenge air, engine cooling system, and lubricant oil system) on container vessels. The project...... included numerical simulations and experimental tests on a 125 kW demonstration ORC unit that utilizes the waste heat of the main engine cooling system on board one of Mærsk's container vessels. During the design of the demonstration ORC unit, different alternatives for the condenser were analyzed in order...... of using ORC units for maritime applications, and the relevance of this technology for new-building projects. Firstly, an evaluation of the waste heat resources available on board Mærsk containers fleet, and an estimation of the potential energy recovery by means of the ORC technology was performed...

  19. Heat-transfer, inside of the ground heat-transfer units, from liquid, additionally cooling the oil-immersed transformer

    Directory of Open Access Journals (Sweden)

    Madyshev Ilnur

    2017-01-01

    Full Text Available A device for cooling the oil-immersed transformer by means of thermoelectric transducers has been developed. Their operating principle is based on the fact that at night at minimum ambient temperature, the cold is accumulated inside of a vessel due to formation of water ice layer on the developed surfaces of thermoelectric transducers` ribs. Melting of this layer is used in the hottest time of a day for additional cooling of transformer oil in the cooling system of the transformer. Pre-cooling of the circulating water takes place in vertical ground heat-transfer units (VGHT units, mounted into ground drilled boreholes. Certain estimate calculations of the heat-transfer process have been carried out.

  20. Thermodynamic investigation of waste heat driven desalination unit based on humidification dehumidification (HDH) processes

    International Nuclear Information System (INIS)

    He, W.F.; Xu, L.N.; Han, D.; Gao, L.; Yue, C.; Pu, W.H.

    2016-01-01

    Highlights: • HDH desalination system powered by waste heat is proposed. • Performance of the desalination unit and the relevant heat recovery effect is calculated. • Sensitive analysis of the performance for the HDH desalination system is investigated. • Mathematical model based on the first and second laws of thermodynamics is established. - Abstract: Humidification dehumidification (HDH) technology is an effective pattern to separate freshwater from seawater or brackish water. In this paper, a closed-air open-water (CAOW) desalination unit coupled with plate heat exchangers (PHEs) is applied to recover the waste heat from the gas exhaust. Sensitivity analysis for the HDH desalination unit as well as the PHEs from the key parameters including the top and initial temperature of the seawater, operation pressure, and the terminal temperature difference (TTD) of the PHEs are accomplished, and the corresponding performance of the whole HDH desalination system is calculated and presented. The simulation results show that the balance condition of the dehumidifier is allowed by the basic thermodynamic laws, followed by a peak value of gained-output-ratio (GOR) and a bottom value of total specific entropy generation. It is concluded that excellent results including the system performance, heat recovery effect and investment of the PHEs can be simultaneously obtained with a low top temperature, while the obtained desalination performance and the heat recovery effect from other measures are always conflicting. Different from other parameters of the desalination unit, the terminal temperature difference of the PHEs has little influences on the final value of GOR.

  1. Calculation method for the seasonal performance of heat pump compact units and validation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wemhoener, C.; Dott, R.; Afjei, Th. [University of Applied Sciences Northwestern Switzerland, Institute of Energy in Buildings, Muttenz (Switzerland); Huber, H.; Helfenfinger, D.; Keller, P.; Furter, R. [University of Applied Sciences Lucerne (HTA), Test center HLKS, Horw (Switzerland)

    2007-02-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) takes a look at compact heat pump units that have been developed for the heating of low energy consumption houses built to MINERGIE or MINERGIE-P standards. These units, which combine the functions of space heating, domestic hot water preparation and ventilation in one unit are described. A testing procedure developed at the University of Applied Science in Lucerne, Switzerland, using a test rig for the measurement of the seasonal performance factor (SPF) is described. A calculation method based on temperature classes for the calculation of the SPF of combined heat pump systems for space heating and domestic hot water preparation that was developed by the Institute of Energy in Buildings at the University of Applied Sciences Northwestern Switzerland is examined. Two pilot plants allowing detailed field monitoring of two compact units are described. One pilot plant installed in a single-family house built to MINERGIE standard in Gelterkinden, Switzerland, provided data on a compact unit. These results of measurements made on this and a further installation in a MINERGIE-P ultra-low energy consumption house in Zeiningen, Switzerland, are presented and discussed. Calculation methods, including exergy considerations are reviewed and their validation is discussed.

  2. Cooperation of Horizontal Ground Heat Exchanger with the Ventilation Unit During Summer - Case Study

    Science.gov (United States)

    Romańska-Zapała, Anna; Furtak, Marcin; Dechnik, Mirosław

    2017-10-01

    Renewable energy sources are used in the modern energy-efficient buildings to improve their energy balance. One of them is used in the mechanical ventilation system ground air heat exchanger (earth-air heat exchanger - EAHX). This solution, right after heat recovery from exhaust air (recuperation), allows the reduction in the energy needed to obtain the desired temperature of supply air. The article presents the results of "in situ" measurements of pipe ground air heat exchanger cooperating with the air handling unit, supporting cooling the building in the summer season, in Polish climatic conditions. The laboratory consists of a ventilation unit intake - exhaust with rotor for which the source of fresh air is the air intake wall and two air intakes field cooperating with the tube with ground air heat exchangers. Selection of the source of fresh air is performed using sprocket with actuators. This system is part of the ventilation system of the Malopolska Laboratory of Energy-Efficient Building (MLBE) building of Cracow University of Technology. The measuring system are, among others, the sensors of parameters of air inlets and outlets of the heat exchanger channels EAHX and weather station that senses the local weather conditions. The measurement data are recorded and archived by the integrated process control system in the building of MLBE. During the study measurements of operating parameters of the ventilation unit cooperating with the selected source of fresh air were performed. Two cases of operation of the system: using EAHX heat exchanger and without it, were analyzed. Potentially the use of ground air heat exchanger in the mechanical ventilation system can reduce the energy demand for heating or cooling rooms by the pre-adjustment of the supply air temperature. Considering the results can be concluded that the continuous use of these exchangers is not optimal. This relationship is appropriate not only on an annual basis for the transitional periods (spring

  3. Calculation method for the seasonal performance of heat pump compact units and validation. Appendix

    Energy Technology Data Exchange (ETDEWEB)

    Wemhoener, C.; Dott, R.; Afjei, Th. [University of Applied Sciences Northwestern Switzerland, Institute of Energy in Buildings, Muttenz (Switzerland); Huber, H.; Helfenfinger, D.; Keller, P.; Furter, R. [University of Applied Sciences Lucerne (HTA), Test center HLKS, Horw (Switzerland)

    2007-02-15

    This appendix to a comprehensive final report for the Swiss Federal Office of Energy (SFOE) presents the results of tests made on compact heat pump units that have been developed for the heating of low energy consumption houses built to MINERGIE or MINERGIE-P standards. The tests on these units, which combine the functions of space heating, domestic hot water preparation and ventilation in one unit are presented and discussed. Test conditions are described; these cover ventilation, acoustic, hygiene and safety aspects. Detailed results from the two test objects - buildings built to MINERGIE and MINERGIE-P low energy consumption standards - are presented and discussed. The calculation methods used are examined and discussed.

  4. SOME METHODS FOR SAVING HEAT ENERGY WHILE MANUFACTURING VERTICAL INSULATING GLASS UNITS

    Directory of Open Access Journals (Sweden)

    S. A. Shybeka

    2018-01-01

    Full Text Available The paper proposes and considers two constructive methods for saving heat energy while manufacturing vertical insulating glass units with various gas filling of inter-glass space. The first method presupposes manufacturing of insulating glass units having specific thickness which is calculated in accordance with specific features of convective heat exchange in the closed loop circuit. Value of the heat-exchange coefficient depends on gas properties which is filling a chamber capacity (coefficients of thermal conductivity, volumetric expansion, kinematic viscosity, thermometric conducivity, temperature difference on the boundary of interlayer and its thickness. It has been shown that while increasing thickness of gas layer convective heat exchange coefficient is initially decreasing up to specific value and then after insignificant increase it practically remains constant. In this connection optimum thicknesses of filled inter-layers for widely-spread gas in production (dry air, argon, krypton, xenon and for carbon dioxide have determined in the paper. Manufacturing of insulating glass units with large thickness of gas chamber practically does not lead to an increase in resistance to heat transfer but it will increase gas consumption rate. The second industrial economic method is interrelated with application of carbon dioxide СО2 as a filler of inter-glass space which has some advantages in comparison with other gases (small cost due to abundance, nontoxicity, transparency for visual light and absorption of heat rays. Calculations have shown that application of carbon dioxide will make it possible to increase resistance to heat transfer of one-chamber glass unit by 0.05 m²×K/W (with emissivity factor of internal glass – 0.837 or by 0.16 m²×K/W (with emission factor – 0.1 in comparison with the glass unit where a chamber is filled with dry air.

  5. Performance analysis of phase-change material storage unit for both heating and cooling of buildings

    Science.gov (United States)

    Waqas, Adeel; Ali, Majid; Ud Din, Zia

    2017-04-01

    Utilisation of solar energy and the night ambient (cool) temperatures are the passive ways of heating and cooling of buildings. Intermittent and time-dependent nature of these sources makes thermal energy storage vital for efficient and continuous operation of these heating and cooling techniques. Latent heat thermal energy storage by phase-change materials (PCMs) is preferred over other storage techniques due to its high-energy storage density and isothermal storage process. The current study was aimed to evaluate the performance of the air-based PCM storage unit utilising solar energy and cool ambient night temperatures for comfort heating and cooling of a building in dry-cold and dry-hot climates. The performance of the studied PCM storage unit was maximised when the melting point of the PCM was ∼29°C in summer and 21°C during winter season. The appropriate melting point was ∼27.5°C for all-the-year-round performance. At lower melting points than 27.5°C, declination in the cooling capacity of the storage unit was more profound as compared to the improvement in the heating capacity. Also, it was concluded that the melting point of the PCM that provided maximum cooling during summer season could be used for winter heating also but not vice versa.

  6. Energy Savings and Breakeven Costs for Residential Heat Pump Water Heaters in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, Jeff [National Renewable Energy Lab. (NREL), Golden, CO (United States); Burch, Jay [National Renewable Energy Lab. (NREL), Golden, CO (United States); Merrigan, Tim [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ong, Sean [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-07-01

    Heat pump water heaters (HPWHs) have recently re-emerged in the U.S. residential water heating market and have the potential to provide homeowners with significant energy savings. However, there are questions as to the actual performance and energy savings potential of these units, in particular in regards to the heat pump's performance in unconditioned space and the impact of the heat pump on space heating and cooling loads when it is located in conditioned space. To help answer these questions, NREL performed simulations of a HPWH in both conditioned and unconditioned space at over 900 locations across the continental United States and Hawaii. Simulations included a Building America benchmark home so that any interaction between the HPWH and the home's HVAC equipment could be captured. Comparisons were performed to typical gas and electric water heaters to determine the energy savings potential and cost effectiveness of a HPWH relative to these technologies. HPWHs were found to have a significant source energy savings potential when replacing typical electric water heaters, but only saved source energy relative to gas water heater in the most favorable installation locations in the southern United States. When replacing an electric water heater, the HPWH is likely to break even in California, the southern United States, and parts of the northeast in most situations. However, the HPWH will only break even when replacing a gas water heater in a few southern states.

  7. Centrifugal Compressor Unit-based Heat Energy Recovery at Compressor Stations

    Directory of Open Access Journals (Sweden)

    V. S. Shadrin

    2016-01-01

    Full Text Available About 95% of the electricity consumed by air compressor stations around the world, is transformed into thermal energy, which is making its considerable contribution to global warming. The present article dwells on the re-use (recovery of energy expended for air compression.The article presents the energy analysis of the process of compressing air from the point of view of compressor drive energy conversion into heat energy. The temperature level of excess heat energy has been estimated in terms of a potential to find the ways of recovery of generated heat. It is shown that the temperature level formed by thermal energy depends on the degree of air compression and the number of stages of the compressor.Analysis of technical characteristics of modern equipment from leading manufacturers, as well as projects of the latest air compressor stations have shown that there are two directions for the recovery of heat energy arising from the air compression: Resolving technological problems of compressor units. The use of the excess heat generation to meet the technology objectives of the enterprise. This article examines the schematic diagrams of compressor units to implement the idea of heat recovery compression to solve technological problems: Heating of the air in the suction line during operation of the compressor station in winter conditions. Using compression heat to regenerate the adsorbent in the dryer of compressed air.The article gives an equity assessment of considered solutions in the total amount of heat energy of compressor station. Presented in the present work, the analysis aims to outline the main vectors of technological solutions that reduce negative impacts of heat generation of compressor stations on the environment and creating the potential for reuse of energy, i.e. its recovery.

  8. Study of the thermal behavior of a latent heat cold storage unit operating under frosting conditions

    International Nuclear Information System (INIS)

    Simard, A.P.; Lacroix, M.

    2003-01-01

    A study is performed of the thermal behavior of a latent heat cold storage unit operating under frosting conditions. This unit is employed to maintain the temperature inside the refrigerated compartment of a truck below 265 K. The system consists of parallel plates filled with a phase change material (PCM) that absorbs heat from the flow of warm moist air. A mathematical model for the system is first presented and, next, validated with numerical and experimental data. It is then exploited to assess the effects of design parameters and operating conditions on the performance of the system. The recommended thickness and distance separating the PCM plates are found to be 50x10 -3 and 30x10 -3 m, respectively. The results indicate that the performance of the unit is enhanced by turbulent air flow in spite of the increased pressure loss and accentuated frost growth. The unit also performs well even when the surrounding relative humidity is 100%

  9. Accelerating the energy policy turnaround with combined heat and power units; Mit Blockheizkraftwerken die Energiewende rund machen

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Joerg; Geiler, Nikolaus [Klimabuendnis Freiburg, Freiburg im Breisgau (Germany)

    2013-03-15

    No other type of decentralized power plants transforms natural gas to electric power so efficiently as a combined heat and power unit. In the long term, the climate-friendly effect using renewable hydrogen or renewably generated 'natural gas' even could be increased. Thus, combined heat and power units are ideal to achieve the national climate change objectives. Despite their advantages, the implementation of combined heat and power units advances only sluggishly.

  10. Study on constraints for heat removal duties of the main fractionator in delayed coking units

    International Nuclear Information System (INIS)

    Lei, Yang; Zhang, Bingjian; Qi, Xin; Chen, Qinglin; Hui, Chi-Wai

    2014-01-01

    A novel method is presented in this paper to quantitatively define the heat removal of the main fractionator in delayed coking units on the basis of a fractionating precision diagram (Houghland diagram) and column grand composite curve (CGCC). By referring to the CGCC method, several envelopes are illustrated at draw trays including the top pumparound draw, diesel draw, intermediate pumparound draw and gas oil draw, the energy and material balances are then calculated. Assuming practical near-minimum thermodynamic condition (PNMTC), the minimum liquid reflux flow is zero in the envelope for pumparound trays without product draw and the minimum liquid reflux flow is defined by Houghland diagram for pumparound trays with product draw. The PNMTC-CGCC is constructed by calculating the enthalpy-flow deficit to quantitatively define the heat removal constraints in each envelope. Meanwhile, the corresponding practical heat removal curve is constructed. A case study shows that the high temperature heat removal ratio within the main fractionator increased by 8%. The proposed method offers heat removal inequality constraints for the model to optimize the heat integration between the main fractionator and the heat exchanger network. - Highlights: • A novel method defines the heat removal constraints of the main fractionator. • Fractionating precision diagram and column grand composite curve are combined. • The results are the inequality constraints in a simultaneous optimization model

  11. He II Heat Exchanger Test Unit for the LHC Inner Triplet

    CERN Document Server

    Blanco-Viñuela, E; Huang, Y; Nicol, T H; Peterson, T; Van Weelderen, R

    2002-01-01

    The Inner Triplet Heat Exchanger Test Unit (IT-HXTU) is a 30-m long thermal model designed at Fermilab, built in US industry, fully automated and tested at CERN as part of the US LHC program to develop the LHC Interaction Region quadrupole system. The cooling scheme of the IT-HXTU is based on heat exchange between stagnant pressurized He II in the magnet cold mass and saturated He II (two-phase) flowing in a heat exchanger located outside of and parallel to the cold mass. The purposes of this test are, among others, to validate the proposed cooling scheme and to define an optimal control strategy to be implemented in the future LHC accelerator. This paper discusses the results for the heat exchanger test runs and emphasizes the thermal and hydraulic behavior of He II for the inner triplet cooling scheme.

  12. Early emergence of anthropogenically forced heat waves in the western United States and Great Lakes

    Science.gov (United States)

    Lopez, Hosmay; West, Robert; Dong, Shenfu; Goni, Gustavo; Kirtman, Ben; Lee, Sang-Ki; Atlas, Robert

    2018-05-01

    Climate projections for the twenty-first century suggest an increase in the occurrence of heat waves. However, the time at which externally forced signals of anthropogenic climate change (ACC) emerge against background natural variability (time of emergence (ToE)) has been challenging to quantify, which makes future heat-wave projections uncertain. Here we combine observations and model simulations under present and future forcing to assess how internal variability and ACC modulate US heat waves. We show that ACC dominates heat-wave occurrence over the western United States and Great Lakes regions, with ToE that occurred as early as the 2020s and 2030s, respectively. In contrast, internal variability governs heat waves in the northern and southern Great Plains, where ToE occurs in the 2050s and 2070s; this later ToE is believed to be a result of a projected increase in circulation variability, namely the Great Plain low-level jet. Thus, greater mitigation and adaptation efforts are needed in the Great Lakes and western United States regions.

  13. Energy Savings and Breakeven Cost for Residential Heat Pump Water Heaters in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, J.; Burch, J.; Merrigan, T.; Ong, S.

    2013-07-01

    Heat pump water heaters (HPWHs) have recently reemerged in the U.S. residential water heating market and have the potential to provide homeowners with significant energy savings. However, there are questions as to the actual performance and energy savings potential of these units, in particular in regards to the heat pump's performance in unconditioned space and the impact of the heat pump on space heating and cooling loads when it is located in conditioned space. To help answer these questions, simulations were performed of a HPWH in both conditioned and unconditioned space at over 900 locations across the continental United States and Hawaii. Simulations included a Building America benchmark home so that any interaction between the HPWH and the home's HVAC equipment could be captured. Comparisons were performed to typical gas and electric water heaters to determine the energy savings potential and cost effectiveness of a HPWH relative to these technologies. HPWHs were found to have a significant source energy savings potential when replacing typical electric water heaters, but only saved source energy relative to gas water heater in the most favorable installation locations in the southern US. When replacing an electric water heater, the HPWH is likely to break even in California, the southern US, and parts of the northeast in most situations. However, the HPWH will only break even when replacing a gas water heater in a few southern states.

  14. Comparison of Advanced Residential Water Heating Technologies in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, Jeff [National Renewable Energy Lab. (NREL), Golden, CO (United States); Fang, Xia [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wilson, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-05-01

    In this study, gas storage, gas tankless, condensing, electric storage, heat pump, and solar water heaters were simulated in several different climates across the United States, installed in both conditioned and unconditioned space and subjected to several different draw profiles. While many pre-existing models were used, new models of condensing and heat pump water heaters were created specifically for this work. In each case modeled, the whole house was simulated along with the water heater to capture any interactions between the water heater and the space conditioning equipment.

  15. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

    Science.gov (United States)

    McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  16. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium

    International Nuclear Information System (INIS)

    McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

    2007-01-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D 2 transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude

  17. HEAT STORAGE SYSTEM WITH PHASE CHANGE MATERIALS IN COGENERATION UNITS: STUDY OF PRELIMINARY MODEL

    Directory of Open Access Journals (Sweden)

    Claudio Caprara

    2008-12-01

    Full Text Available The continuous increase in the mechanization of farm activities, the rise in fuel prices and the environmental aspects concerning gas emissions are the main driving forces behind efforts toward more effective use of renewable energy sources and cogeneration systems even in agricultural and cattle farms. Nevertheless these systems are still not very suitable for this purpose because of their little flexibility in following the changing energy demand as opposed to the extremely various farm load curves, both in daytime and during the year. In heat recovery systems, the available thermal energy supply is always linked to power production, thus it does not usually coincide in time with the heat demand. Hence some form of thermal energy storage (TES is necessary in order to reach the most effective utilization of the energy source. This study deals with the modelling of a packed bed latent heat TES unit, integrating a cogeneration system made up of a reciprocating engine. The TES unit contains phase change materials (PCMs filled in spherical capsules, which are packed in an insulated cylindrical storage tank. Water is used as heat transfer fluid (HTF to transfer heat from the tank to the final uses, and exhausts from the engine are used as thermal source. PCMs are considered especially for their large heat storage capacity and their isothermal behaviour during the phase change processes. Despite their high energy storage density, most of them have an unacceptably low thermal conductivity, hence PCMs encapsulation technique is adopted in order to improve heat transfer. The special modular configuration of heat exchange tubes and the possibility of changing water flow through them allow to obtain the right amount of thermal energy from the tank, according to the hourly demand of the day. The model permits to choose the electrical load of the engine, the dimensions of the tank and the spheres, thickness and diameter of heat exchanger and the nature of

  18. Method for heating of the primary circuit of WWER electric power units at cold start-up

    International Nuclear Information System (INIS)

    Ivanov, I.N.; Dimitrov, B.D.; Korkinova, M.I.

    1982-01-01

    The method increases the heating rate and shorten the start-up time of the electric power units. It comprises a primary stopping of the reactor core heating and provides a forced circulation of the heat-carrier through the circulation cycles of the primary circuit. The thermal energy is supplied in one or several steam generators in the secondary circuit of an NPP operating unit. 1 cl., 3 figs

  19. Evaluation of the performance of combined cooling, heating, and power systems with dual power generation units

    International Nuclear Information System (INIS)

    Knizley, Alta A.; Mago, Pedro J.; Smith, Amanda D.

    2014-01-01

    The benefits of using a combined cooling, heating, and power system with dual power generation units (D-CCHP) is examined in nine different U.S. locations. One power generation unit (PGU) is operated at base load while the other is operated following the electric load. The waste heat from both PGUs is used for heating and for cooling via an absorption chiller. The D-CCHP configuration is studied for a restaurant benchmark building, and its performance is quantified in terms of operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE). Cost spark spread, PEC spark spread, and CDE spark spread are examined as performance indicators for the D-CCHP system. D-CCHP system performance correlates well with spark spreads, with higher spark spreads signifying greater savings through implementation of a D-CCHP system. A new parameter, thermal difference, is introduced to investigate the relative performance of a D-CCHP system compared to a dual PGU combined heat and power system (D-CHP). Thermal difference, together with spark spread, can explain the variation in savings of a D-CCHP system over a D-CHP system for each location. The effect of carbon credits on operational cost savings with respect to the reference case is shown for selected locations. - Highlights: • We investigate benefits from using combined cooling, heating, and power systems. • A dual power generation unit configuration is considered for CCHP and CHP. • Spark spreads for cost, energy, and emissions correlate with potential savings. • Thermal difference parameter helps to explain variations in potential savings. • Carbon credits may increase cost savings where emissions savings are possible

  20. A Direct Heat Exchanger Unit used for Domestic Hot Water Supply in a Single-family House Supplied by Low Energy District Heating

    DEFF Research Database (Denmark)

    Brand, Marek; Thorsen, Jan Eric; Svendsen, Svend

    2010-01-01

    The increasing number of new and renovated buildings with reduced heating requirements will soon make traditional District Heating (DH) systems uneconomic. To keep DH competitive in the future, the heat loss in DH networks needs to be reduced. One option is to reduce the supply temperature of DH...... as much as possible. This requires a review of the behaviour of the whole domestic hot water (DHW) supply system with focus on the user comfort and overall costs. This paper describes some practical approaches to the implementation of this Low Energy District Heating (LEDH) concept. It reports...... on the testing of the dynamic behaviour of an Instantaneous Heat Exchanger Unit(IHEU) designed for DHW heating and space heating in detached family houses supplied by LEDH ensuring an entry-to-substation temperature of 51 °C. We measured the time it takes for the IHEU to produce DHW with a temperature of 42 °C...

  1. ANALYSIS OF THE INFLUENCE OF PARAMETERS OF CONTROL OF HEATING POWER GENERATING UNITS ON FUEL CONSUMPTION

    Directory of Open Access Journals (Sweden)

    Shchinnikov P.A.

    2011-04-01

    Full Text Available It is presented analysis of the influence of parameters of state of the process of control on the increase of the fuel consumption of heat power generating units. There are presented results of calculations of the increase of the fuel consumption at the deviation of the working steam temperature and pressure from rated values. Result of calculus is compared with the experiment.

  2. Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

    OpenAIRE

    Dongmin Yu; Yuanzhu Meng; Gangui Yan; Gang Mu; Dezhi Li; Simon Le Blond

    2017-01-01

    Many combined heat and power (CHP) units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity ...

  3. Thermal-economic optimization of an air-cooled heat exchanger unit

    International Nuclear Information System (INIS)

    Alinia Kashani, Amir Hesam; Maddahi, Alireza; Hajabdollahi, Hassan

    2013-01-01

    Thermodynamic modeling and optimal design of an air-cooled heat exchanger (ACHE) unit are developed in this study. For this purpose, ε–NTU method and mathematical relations are applied to estimate the fluids outlet temperatures and pressure drops in tube and air sides. The main goal of this study is minimizing of two conflicting objective functions namely the temperature approach and the minimum total annual cost, simultaneously. For this purpose, fast and elitist non-dominated sorting genetic-algorithm (NSGA-II) is applied to minimize the objective functions by considering ten design parameters. In addition, a set of typical constraints, governing on the ACHE unit design, is subjected to obtain more practical optimum design points. Furthermore, sensitivity analysis of change in the objective functions, when the optimum design parameters vary, is conducted and the degree of each parameter on conflicting objective functions has been investigated. Finally, a selection procedure of the best optimum point is introduced and final optimum design point is determined. -- Highlights: ► Multi-objective optimization of air-cooled heat exchanger. ► Considering ten new design parameters in this type of heat exchanger. ► A detailed cost function is used to estimate the heat exchanger investment cost. ► Presenting a mathematical relation for optimum total cost vs. temperature approach. ► The sensitivity analysis of parameters in the optimum situation

  4. Exertional heat stroke management strategies in United States high school football.

    Science.gov (United States)

    Kerr, Zachary Y; Marshall, Stephen W; Comstock, R Dawn; Casa, Douglas J

    2014-01-01

    The 5-year period of 2005-2009 saw more exertional heat stroke-related deaths in organized sports than any other 5-year period in the past 35 years. The risk of exertional heat stroke appears highest in football, particularly during the preseason. To estimate the incidence of exertional heat stroke events and assess the utilization of exertional heat stroke management strategies during the 2011 preseason in United States high school football programs. Cross-sectional study; Level of evidence, 3. A self-administered online questionnaire addressing the incidence of exertional heat stroke events and utilization of exertional heat stroke management strategies (eg, removing athlete's football equipment, calling Emergency Medical Services [EMS]) was completed in May to June 2012 by 1142 (18.0%) athletic trainers providing care to high school football athletes during the 2011 preseason. Among all respondents, 20.3% reported treating at least 1 exertional heat stroke event. An average of 0.50 ± 1.37 preseason exertional heat stroke events were treated per program. Athletic trainers responding to exertional heat stroke reported using an average of 6.6 ± 1.8 management strategies. The most common management strategies were low-level therapeutic interventions such as removing the athlete's football equipment (98.2%) and clothing (77.8%) and moving the athlete to a shaded area (91.6%). Few athletic trainers reported active management strategies such as calling EMS (29.3%) or using a rectal thermometer to check core body temperature (0.9%). Athletic trainers in states with mandated preseason heat acclimatization guidelines reported a higher utilization of management strategies such as cooling the athlete through air conditioning (90.1% vs 65.0%, respectively; P football programs. The standard of care is (and should be) to treat proactively; therefore, treatment is not a perfect proxy for incidence. Nevertheless, there is an urgent need for improved education and awareness of

  5. Emission factors of modern wood-pellet heating units under typical heating conditions - Final report; Emissionsfaktoren moderner Pelletkessel unter typischen Heizbedingungen - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Good, J.; Nussbaumer, T.

    2009-12-15

    This final report for the Swiss Federal Office of Energy (SFOE) reports on the results of measurements made concerning the emission factors of two modern wood-pellet heating units under typical heating conditions. Using simulations, typical operation in single-family homes and apartment blocks were examined. Emissions during the different phases of operation were examined. Systems with and without buffer storage were also examined. The minimum running times to be striven for are quoted which would lead to a reduction of emissions to an acceptable level. The characteristic operating modes for the two heating units and the results obtained for various emissions are presented and discussed.

  6. Heat stress control in the TMI-2 [Three Mile Island Unit 2] defueling and decontamination activities

    International Nuclear Information System (INIS)

    Schork, J.S.; Parfitt, B.A.

    1988-01-01

    During the initial stages of the Three Mile Island Unit 2 (TMI-2) defueling and decontamination activities for the reactor building, it was realized that the high levels of loose radioactive contamination would require the use of extensive protective clothing by entry personnel. While there was no doubt that layered protective clothing protects workers from becoming contaminated, it was recognized that these same layers of clothing would impose a very significant heat stress burden. To prevent the potentially serious consequences of a severe reaction to heat stress by workers in the hostile environment of the TMI-2 reactor building and yet maintain the reasonable work productivity necessary to perform the recovery adequately, an effective program of controlling worker exposure to heat stress had to be developed. Body-cooling devices produce a flow of cool air, which is introduced close to the skin to remove body heat through convection and increased sweat evaporation. The cooling effect produced by the Vortex tube successfully protected the workers from heat stress, however, there were several logistical and operational problems that hindered extensive use of these devices. The last type of cooling garment examined was the frozen water garment (FWG) developed by Elizier Kamon at the Pennsylvania State University as part of an Electric Power Research Institute research grant. Personal protection, i.e., body cooling, engineering controls, and administrative controls, have been implemented successfully

  7. Heat transfer and thermal storage performance of an open thermosyphon type thermal storage unit with tubular phase change material canisters

    International Nuclear Information System (INIS)

    Wang, Ping-Yang; Hu, Bo-Wen; Liu, Zhen-Hua

    2015-01-01

    Highlights: • A novel open heat pipe thermal storage unit is design to improve its performance. • Mechanism of its operation is phase-change heat transfer. • Tubular canisters with phase change material were placed in thermal storage unit. • Experiment and analysis are carried out to investigate its operation properties. - Abstract: A novel open thermosyphon-type thermal storage unit is presented to improve design and performance of heat pipe type thermal storage unit. In the present study, tubular canisters filled with a solid–liquid phase change material are vertically placed in the middle of the thermal storage unit. The phase change material melts at 100 °C. Water is presented as the phase-change heat transfer medium of the thermal storage unit. The tubular canister is wrapped tightly with a layer of stainless steel mesh to increase the surface wettability. The heat transfer mechanism of charging/discharging is similar to that of the thermosyphon. Heat transfer between the heat resource or cold resource and the phase change material in this device occurs in the form of a cyclic phase change of the heat-transfer medium, which occurs on the surface of the copper tubes and has an extremely high heat-transfer coefficient. A series of experiments and theoretical analyses are carried out to investigate the properties of the thermal storage unit, including power distribution, start-up performance, and temperature difference between the phase change material and the surrounding vapor. The results show that the whole system has excellent heat-storage/heat-release performance

  8. Optimization model of a system of crude oil distillation units whit heat integration and meta modeling

    International Nuclear Information System (INIS)

    Lopez, Diana C; Mahecha, Cesar A; Hoyos, Luis J; Acevedo, Leonardo; Villamizar Jaime F

    2009-01-01

    The process of crude distillation impacts the economy of any refinery in a considerable manner. Therefore, it is necessary to improve it taking good advantage of the available infrastructure, generating products that conform to the specifications without violating the equipment operating constraints or plant restrictions at industrial units. The objective of this paper is to present the development of an optimization model for a Crude Distillation Unit (CDU) system at a ECOPETROL S.A. refinery in Barrancabermeja, involving the typical restrictions (flow according to pipeline capacity, pumps, distillation columns, etc) and a restriction that has not been included in bibliographic reports for this type of models: the heat integration of streams from Atmospheric Distillation Towers (ADTs) and Vacuum Distillation Towers (VDT) with the heat exchanger networks for crude pre-heating. On the other hand, ADTs were modeled with Meta models in function of column temperatures and pressures, pumparounds flows and return temperatures, stripping steam flows, Jet EBP ASTM D-86 and Diesel EBP ASTM D-86. Pre-heating trains were modeled with mass and energy balances, and design equation of each heat exchanger. The optimization model is NLP, maximizing the system profit. This model was implemented in GAMSide 22,2 using the CONOPT solver and it found new operating points with better economic results than those obtained with the normal operation in the real plants. It predicted optimum operation conditions of 3 ADTs for constant composition crude and calculated the yields and properties of atmospheric products, additional to temperatures and duties of 27 Crude Oil exchangers.

  9. Optimization model of a system of crude oil distillation units with heat integration and metamodeling

    International Nuclear Information System (INIS)

    Lopez, Diana C; Mahecha, Cesar A; Hoyos, Luis J; Acevedo, Leonardo; Villamizar Jaime F

    2010-01-01

    The process of crude distillation impacts the economy of any refinery in a considerable manner. Therefore, it is necessary to improve it taking good advantage of the available infrastructure, generating products that conform to the specifications without violating the equipment operating constraints or plant restrictions at industrial units. The objective of this paper is to present the development of an optimization model for a Crude Distillation Unit (CDU) system at a ECOPETROL S.A. refinery in Barrancabermeja, involving the typical restrictions (flow according to pipeline capacity, pumps, distillation columns, etc) and a restriction that has not been included in bibliographic reports for this type of models: the heat integration of streams from Atmospheric Distillation Towers (ADTs) and Vacuum Distillation Towers (VDT) with the heat exchanger networks for crude pre-heating. On the other hand, ADTs were modeled with Metamodels in function of column temperatures and pressures, pump a rounds flows and return temperatures, stripping steam flows, Jet EBP ASTM D-86 and Diesel EBP ASTM D-86. Pre-heating trains were modeled with mass and energy balances, and design equation of each heat exchanger. The optimization model is NLP, maximizing the system profit. This model was implemented in GAMSide 22,2 using the CONOPT solver and it found new operating points with better economic results than those obtained with the normal operation in the real plants. It predicted optimum operation conditions of 3 ADTs for constant composition crude and calculated the yields and properties of atmospheric products, additional to temperatures and duties of 27 Crude Oil exchangers.

  10. Heat recovery from UPS units - Analysis of a first unit and technology assessment; Waermerueckgewinnung in USV-Anlagen. Analyse einer Erstanlage und Potentialabschaetzung

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, S.; Schlegel, A.

    2009-11-15

    UPS units (uninterruptible power supply) generate large heat losses, which have to be dissipated with cooling units. awtec has developed a unique UPS system with integrated heat recovery which was installed in 2001 (Building Gretag/SAP in Regensdorf) and which is still running error-free. With this system the waste heat can be recovered and electrical energy for the refrigeration system can be saved likewise. The measured data shows that during the heating season, the unit transfers virtually all heat loss (about 20 MWh/year) to the space heating system. The building's refrigeration system, however, has its own heat recovery system, so the actual annual energy savings can be estimated to be only about 4 MWh of electricity. The prototype shows that awtec built a robust unit which - given an appropriate cooling and heating system - has the potential for high energy savings (without central heat recovery system: 4 MWh electric + 20 MWh thermal) without increased investment. Based on the UPS heat recovery development, previous projects of the Swiss Federal Office of Energy and a market survey, scenarios for the cooling and heat recovery from UPS units were developed. Since the same concepts also apply to the cooling of servers and other IT components, they were also included in the analysis. The scenario analysis shows that a high potential for savings of electric energy and heat exists in this area. In particular, the direct cooling of the IT components with cooling water offers big benefits for heat recovery and free cooling (cooling without the use of the refrigeration system) compared to conventional air cooling. These direct cooling systems are currently mainly used for special applications or as a fallback in case of overheating problems. Passive cooling through geothermal probes, which are now mainly used for buildings with small heat pump systems, provides an interesting approach to the cooling of IT equipment in accordance with the temperature level. It

  11. Heat Exchange and Fouling Analysis on a Set of Hydrogen Sulphide Gas Coolers

    Directory of Open Access Journals (Sweden)

    Andrés Adrian Sánchez-Escalona

    2017-07-01

    Full Text Available The sulphide acid coolers are tube and shell jacketed heat exchangers designed to cool down the produced gas from 416,15 K to 310,15 K in addition to separate the sulphur carried over by the outlet gas from the reactor tower. The investigation was carried out by applying the passive experimentation process in an online cooler set in order to determine the heat transfer rates and fouling based on heat resistance. It was corroborated that the operation of this equipment outside design parameters increases outlet gas temperature and liquid sulphur carryovers. Efficiency loss is caused by fouling elements in the fluid, which results in changes in the overall heat transfer rate. The linear tendency of the fouling heat resistance based on time for three gas flowrates.

  12. Global Warming Impacts on Heating and Cooling Degree-Days in the United States

    Science.gov (United States)

    Petri, Y.; Caldeira, K.

    2014-12-01

    Anthropogenic climate change is expected to significantly alter residential air conditioning and space heating requirements, which account for 41% of U.S. household energy expenditures. The degree-day method can be used for reliable estimation of weather related building energy consumption and costs, as well as outdoor climatic thermal comfort. Here, we use U.S. Climate Normals developed by NOAA based on weather station observations along with Climate Model Intercomparison Project phase 5 (CMIP5) multi-model ensemble simulations. We add the projected change in heating and cooling degree-days based on the climate models to the estimates based on the NOAA U.S. Climate Normals to project future heating and cooling degree-days. We find locations with the lowest and highest combined index of cooling (CDDs) and heating degree-days (HDDs) for the historical period (1981 - 2010) and future period (2080 - 2099) under the Representation Concentration Pathway 8.5 (RCP8.5) climate change scenario. Our results indicate that in both time frames and among the lower 48 states, coastal areas in the West and South California will have the smallest degree-day sum (CDD + HDD), and hence from a climatic perspective become the best candidates for residential real estate. The Rocky Mountains region in Wyoming, in addition to northern Minnesota and North Dakota, will have the greatest CDD + HDD. While global warming is projected to reduce the median heating and cooling demand (- 5%) at the end of the century, CDD + HDD will decrease in the North, with an opposite effect in the South. This work could be helpful in deciding where to live in the United States based on present and future thermal comfort, and could also provide a basis for estimates of changes in heating and cooling energy demand.

  13. Heat Flow and Geothermal Potential in the South-Central United States

    International Nuclear Information System (INIS)

    Negraru, Petru T.; Blackwell, David D.; Erkan, Kamil

    2008-01-01

    Geothermal exploration is typically limited to high-grade hydrothermal reservoirs that are usually found in the western United States, yet large areas with subsurface temperatures above 150 deg. C at economic drilling depths can be found east of the Rocky Mountains. The object of this paper is to present new heat flow data and to evaluate the geothermal potential of Texas and adjacent areas. The new data show that, west of the Ouachita Thrust Belt, the heat flow values are lower than east of the fault zone. Basement heat flow values for the Palo Duro and Fort Worth Basins are below 50 mW/m 2 while, in the frontal zone of the belt, they can exceed 60 mW/m 2 . Further east, along the Balcones fault system the heat flow is in general higher than 55 mW/m 2 . The eastern most heat flow sites are in Louisiana and they show very high heat flow (over 80 mW/m 2 ), which is associated with the apparently highly radioactive basement of the Sabine uplift. The geothermal resource in this area is large and diverse, and can be divided in high grade (temperature above 150 deg. C) convective systems, conductive based enhanced geothermal systems and geothermal/geopressured systems. One of the most attractive areas east of the cordillera extends from eastern Texas across Louisiana and Arkansas to western Mississippi. Here temperatures reach exploitation range at depths below 4 km, and tapping such a resource from shut in hydrocarbon fields is relatively easy. The initial costs of the development can be greatly reduced if existing hydrocarbon infrastructure is used, and therefore using shut-in hydrocarbon fields for geothermal purposes should not be neglected

  14. The energy efficiency ratio of heat storage in one shell-and-one tube phase change thermal energy storage unit

    International Nuclear Information System (INIS)

    Wang, Wei-Wei; Wang, Liang-Bi; He, Ya-Ling

    2015-01-01

    Highlights: • A parameter to indicate the energy efficiency ratio of PCTES units is defined. • The characteristics of the energy efficiency ratio of PCTES units are reported. • A combined parameter of the physical properties of the working mediums is found. • Some implications of the energy efficiency ratio in design of PCTES units are analyzed. - Abstract: From aspect of energy consuming to pump heat transfer fluid, there is no sound basis on which to create an optimum design of a thermal energy storage unit. Thus, it is necessary to develop a parameter to indicate the energy efficiency of such unit. This paper firstly defines a parameter that indicates the ratio of heat storage of phase change thermal energy storage unit to energy consumed in pumping heat transfer fluid, which is called the energy efficiency ratio, then numerically investigates the characteristics of this parameter. The results show that the energy efficiency ratio can clearly indicate the energy efficiency of a phase change thermal energy storage unit. When the fluid flow of a heat transfer fluid is in a laminar state, the energy efficiency ratio is larger than in a turbulent state. The energy efficiency ratio of a shell-and-tube phase change thermal energy storage unit is more sensitive to the outer tube diameter. Under the same working conditions, within the heat transfer fluids studied, the heat storage property of the phase change thermal energy storage unit is best for water as heat transfer fluid. A combined parameter is found to indicate the effects of both the physical properties of phase change material and heat transfer fluid on the energy efficiency ratio

  15. Use of Artificial Neural Networks for Prediction of Convective Heat Transfer in Evaporative Units

    Directory of Open Access Journals (Sweden)

    Romero-Méndez Ricardo

    2014-01-01

    Full Text Available Convective heat transfer prediction of evaporative processes is more complicated than the heat transfer prediction of single-phase convective processes. This is due to the fact that physical phenomena involved in evaporative processes are very complex and vary with the vapor quality that increases gradually as more fluid is evaporated. Power-law correlations used for prediction of evaporative convection have proved little accuracy when used in practical cases. In this investigation, neural-network-based models have been used as a tool for prediction of the thermal performance of evaporative units. For this purpose, experimental data were obtained in a facility that includes a counter-flow concentric pipes heat exchanger with R134a refrigerant flowing inside the circular section and temperature controlled warm water moving through the annular section. This work also included the construction of an inverse Rankine refrigeration cycle that was equipped with measurement devices, sensors and a data acquisition system to collect the experimental measurements under different operating conditions. Part of the data were used to train several neural-network configurations. The best neural-network model was then used for prediction purposes and the results obtained were compared with experimental data not used for training purposes. The results obtained in this investigation reveal the convenience of using artificial neural networks as accurate predictive tools for determining convective heat transfer rates of evaporative processes.

  16. Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

    Directory of Open Access Journals (Sweden)

    Dongmin Yu

    2017-06-01

    Full Text Available Many combined heat and power (CHP units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity and heat loads are firstly used as sizing criteria in finding the best capacities of different types of CHP with the help of the maximum rectangle (MR method. Subsequently, the genetic algorithm (GA will be used to optimise the daily energy costs of the different cases. Then, heat and electricity loads are jointly considered for sizing different types of CHP and for optimising the daily energy costs through the GA method. The optimisation results show that the GA sizing method gives a higher average daily energy cost saving, which is 13% reduction compared to a building without installing CHP. However, to achieve this, there will be about 3% energy efficiency reduction and 7% input power to rated power ratio reduction compared to using the MR method and heat demand in sizing CHP.

  17. A basic study on Thermosyphon-type thermal storage unit (TSU) using Nanofluid as the heat transfer medium

    Science.gov (United States)

    Li, Shuang-Fei; Wang, Ping-Yang; Liu, Zhen-hua

    2017-11-01

    This study proposed a novel thermosyphon-type thermal storage unit using water-based CuO nanofluid as the phase-change heat transfer medium. Seven tubular canisters containing solid-liquid phase-change material (PCM) with peak melting temperature of 100 °C were placed vertically into the center of the TSU which is a vertical cylindrical vessel made of stainless steel. Coat formed by depositing nanoparticles during the phase-change process was adopted to increase the wettability of the heat transfer surfaces of the canisters. We investigated the phase-change heat transfer, as well as the heat-storage and heat-release properties, of the TSU through experimental and computational analysis. Our results demonstrate that this thermal storage unit construction can propose good heat transfer and heat-storage/heat-release performance. The coating of nanoparticles onto the heat transfer surfaces increases the surface wettability and improves both the evaporation and condensation heat transfer. The main thermal resistance in the TSU results from the conductive heat transfer inside of the PCM. All phase-change thermal resistance of liquid film in charging and discharging processes can be ignored in this TSU.

  18. A basic study on Thermosyphon-type thermal storage unit (TSU) using Nanofluid as the heat transfer medium

    Science.gov (United States)

    Li, Shuang-Fei; Wang, Ping-Yang; Liu, Zhen-hua

    2018-05-01

    This study proposed a novel thermosyphon-type thermal storage unit using water-based CuO nanofluid as the phase-change heat transfer medium. Seven tubular canisters containing solid-liquid phase-change material (PCM) with peak melting temperature of 100 °C were placed vertically into the center of the TSU which is a vertical cylindrical vessel made of stainless steel. Coat formed by depositing nanoparticles during the phase-change process was adopted to increase the wettability of the heat transfer surfaces of the canisters. We investigated the phase-change heat transfer, as well as the heat-storage and heat-release properties, of the TSU through experimental and computational analysis. Our results demonstrate that this thermal storage unit construction can propose good heat transfer and heat-storage/heat-release performance. The coating of nanoparticles onto the heat transfer surfaces increases the surface wettability and improves both the evaporation and condensation heat transfer. The main thermal resistance in the TSU results from the conductive heat transfer inside of the PCM. All phase-change thermal resistance of liquid film in charging and discharging processes can be ignored in this TSU.

  19. Cogeneration of heat and electricity from rape oil with a little CHP unit in a car wash

    International Nuclear Information System (INIS)

    Pilz, H.D.; Thomas, S.; Zeilinger, J.

    2002-01-01

    Environmentally friendly energy supply system for smaller houses is described. In Elsbett system the so-called multi fuel engine starts the combined electricity and heat production unit. In such a system one can use also natural fuels, animal oils and fats besides heating oil. Therefore no additional CO 2 is produced, but it will be brought to the balanced natural circle

  20. Heat waves in the United States: mortality risk during heat waves and effect modification by heat wave characteristics in 43 U.S. communities.

    Science.gov (United States)

    Anderson, G Brooke; Bell, Michelle L

    2011-02-01

    Devastating health effects from recent heat waves, and projected increases in frequency, duration, and severity of heat waves from climate change, highlight the importance of understanding health consequences of heat waves. We analyzed mortality risk for heat waves in 43 U.S. cities (1987-2005) and investigated how effects relate to heat waves' intensity, duration, or timing in season. Heat waves were defined as ≥ 2 days with temperature ≥ 95th percentile for the community for 1 May through 30 September. Heat waves were characterized by their intensity, duration, and timing in season. Within each community, we estimated mortality risk during each heat wave compared with non-heat wave days, controlling for potential confounders. We combined individual heat wave effect estimates using Bayesian hierarchical modeling to generate overall effects at the community, regional, and national levels. We estimated how heat wave mortality effects were modified by heat wave characteristics (intensity, duration, timing in season). Nationally, mortality increased 3.74% [95% posterior interval (PI), 2.29-5.22%] during heat waves compared with non-heat wave days. Heat wave mortality risk increased 2.49% for every 1°F increase in heat wave intensity and 0.38% for every 1-day increase in heat wave duration. Mortality increased 5.04% (95% PI, 3.06-7.06%) during the first heat wave of the summer versus 2.65% (95% PI, 1.14-4.18%) during later heat waves, compared with non-heat wave days. Heat wave mortality impacts and effect modification by heat wave characteristics were more pronounced in the Northeast and Midwest compared with the South. We found higher mortality risk from heat waves that were more intense or longer, or those occurring earlier in summer. These findings have implications for decision makers and researchers estimating health effects from climate change.

  1. Flue gas moisture capacity calculation at the outlet of the condensation heat recovery unit

    Directory of Open Access Journals (Sweden)

    Galashov Nikolay

    2017-01-01

    Full Text Available As a result, study equation has been obtained which determine the flue gas moisture capacity at the outlet of the condensation heat recovery unit with an error of less than 1%. It possible to at the temperature of the flue gas below the dew point and the known air-fuel ratio efficient. The equation can be used to calculate plants operating on products of gas combustion without Use of tables and programs for calculating the water-vapor saturation pressure.

  2. Thermal Analysis of a Thermal Energy Storage Unit to Enhance a Workshop Heating System Driven by Industrial Residual Water

    Directory of Open Access Journals (Sweden)

    Wenqiang Sun

    2017-02-01

    Full Text Available Various energy sources can be used for room heating, among which waste heat utilization has significantly improved in recent years. However, the majority of applicable waste heat resources are high-grade or stable thermal energy, while the low-grade or unstable waste heat resources, especially low-temperature industrial residual water (IRW, are insufficiently used. A thermal energy storage (TES unit with paraffin wax as a phase change material (PCM is designed to solve this problem in a pharmaceutical plant. The mathematical models are developed to simulate the heat storage and release processes of the TES unit. The crucial parameters in the recurrence formulae are determined: the phase change temperature range of the paraffin wax used is 47 to 56 °C, and the latent heat is 171.4 kJ/kg. Several thermal behaviors, such as the changes of melting radius, solidification radius, and fluid temperature, are simulated. In addition, the amount of heat transferred, the heat transfer rate, and the heat storage efficiency are discussed. It is presented that the medicine production unit could save 10.25% of energy consumption in the investigated application.

  3. Heat Mortality Versus Cold Mortality: A Study of Conflicting Databases in the United States.

    Science.gov (United States)

    Dixon, P. G.; Brommer, D. M.; Hedquist, B. C.; Kalkstein, A. J.; Goodrich, G. B.; Walter, J. C.; Dickerson, C. C., IV; Penny, S. J.; Cerveny, R. S.

    2005-07-01

    Studies, public reports, news reports, and Web sites cite a wide range of values associated with deaths resulting from excessive heat and excessive cold. For example, in the United States, the National Climatic Data Center's Storm Data statistics of temperature- related deaths are skewed heavily toward heat-related deaths, while the National Center for Health Statistics Compressed Mortality Database indicates the reverse—4 times more people die of “excessive cold” conditions in a given year than of “excessive heat.” In this study, we address the fundamental differences in the various temperature-related mortality databases, assess their benefits and limitations, and offer suggestions as to their use. These datasets suffer from potential incompleteness of source information, long compilation times, limited quality control, and the subjective determination of a direct versus indirect cause of death. In general, these separate mortality datasets should not be combined or compared, particularly with regard to policy determination. The use of gross mortality numbers appears to be one of the best means of determining temperature-related mortality, but those data must be detrended into order to remove a persistent winter-dominant death maximum and are difficult to obtain on a regional daily basis.

  4. Impacts of global warming on residential heating and cooling degree-days in the United States.

    Science.gov (United States)

    Petri, Yana; Caldeira, Ken

    2015-08-04

    Climate change is expected to decrease heating demand and increase cooling demand for buildings and affect outdoor thermal comfort. Here, we project changes in residential heating degree-days (HDD) and cooling degree-days (CDD) for the historical (1981-2010) and future (2080-2099) periods in the United States using median results from the Climate Model Intercomparison Project phase 5 (CMIP5) simulations under the Representation Concentration Pathway 8.5 (RCP8.5) scenario. We project future HDD and CDD values by adding CMIP5 projected changes to values based on historical observations of US climate. The sum HDD + CDD is an indicator of locations that are thermally comfortable, with low heating and cooling demand. By the end of the century, station median HDD + CDD will be reduced in the contiguous US, decreasing in the North and increasing in the South. Under the unmitigated RCP8.5 scenario, by the end of this century, in terms of HDD and CDD values considered separately, future New York, NY, is anticipated to become more like present Oklahoma City, OK; Denver, CO, becomes more like Raleigh, NC, and Seattle, WA, becomes more like San Jose, CA. These results serve as an indicator of projected climate change and can help inform decision-making.

  5. Experimental comparison between R409A and R437A performance in a heat pump unit

    Directory of Open Access Journals (Sweden)

    Duarte M. V.

    2017-04-01

    Full Text Available This paper reports an experimental comparison between the use of the refrigerants R409A and R437A in a heat pump unit designed and developed to work with R12. Although the use of both refrigerants in new equipments were abolished in EU and US according the new F-Gas Regulation of EU and SNAP, they still being used as options for R12 in old equipments, especially in developing countries. Both refrigerants were studied for the same test conditions, according to two groups of tests: group A (variation of the heat source temperature and group B (variation of refrigerant flow rate. The results obtained showed that the R437A presents a higher discharge pressure and a lower discharge temperature. The heating and cooling capacities of both refrigerants were similar, as well as the exergetic efficiency. For the group A of tests the COP of both refrigerants was similar and for the group B of tests the R409A presented an average COP 15% higher. According to the results obtained it is recommended the use of R409A in old equipments (as transition refrigerant until the acquisition of equipments operating with refrigerants with low-GWP becomes technically and economic feasible.

  6. Impacts of global warming on residential heating and cooling degree-days in the United States

    Science.gov (United States)

    Petri, Yana; Caldeira, Ken

    2015-01-01

    Climate change is expected to decrease heating demand and increase cooling demand for buildings and affect outdoor thermal comfort. Here, we project changes in residential heating degree-days (HDD) and cooling degree-days (CDD) for the historical (1981–2010) and future (2080–2099) periods in the United States using median results from the Climate Model Intercomparison Project phase 5 (CMIP5) simulations under the Representation Concentration Pathway 8.5 (RCP8.5) scenario. We project future HDD and CDD values by adding CMIP5 projected changes to values based on historical observations of US climate. The sum HDD + CDD is an indicator of locations that are thermally comfortable, with low heating and cooling demand. By the end of the century, station median HDD + CDD will be reduced in the contiguous US, decreasing in the North and increasing in the South. Under the unmitigated RCP8.5 scenario, by the end of this century, in terms of HDD and CDD values considered separately, future New York, NY, is anticipated to become more like present Oklahoma City, OK; Denver, CO, becomes more like Raleigh, NC, and Seattle, WA, becomes more like San Jose, CA. These results serve as an indicator of projected climate change and can help inform decision-making. PMID:26238673

  7. Analysis of chiller units capacity for different heat loads considering variation of ambient air and cooling water temperature

    International Nuclear Information System (INIS)

    Coman, Aurelia Camelia; Tenescu, Mircea

    2010-01-01

    The paper purpose is to analyze the chiller units capacity to determine whether they can cope with high air and cooling water temperatures during summer time to remove heat loads imposed from Heating, Ventilation and Air Conditioning (HVAC) units in a CANDU 6 Nuclear Power Plant. The starting point is calculation of the overall heat transfer coefficient at the evaporator and condenser. They are used in heat balance equations of heat exchangers. A mathematical model was developed that simulates the refrigeration cycle to assess the response of chilled water system and its performance at different heat loads. In this analysis there were calculated values for inlet/outlet chilled water temperature and the refrigerant cycle thermodynamic parameters (condenser and evaporator pressure/temperature, refrigerant mass flowrate, refrigerant quality at the evaporator, refrigerant vapour superheated temperature at the compressor outlet, refrigerant subcooled temperature at the condenser outlet). To find the adequate functioning parameters of the installation, the MathCAD 13 software was used in all cases analyzed. The behaviour of the chiller units was investigated by examining the variation of three basic parameters, namely: - cooling water (river water) temperature; - air temperature; - heat load. The simultaneous variation of these three independent parameters allows to identify the actual chillers unit operating point (including chiller trip). (authors)

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

    International Nuclear Information System (INIS)

    Wang, Yang; Zhao, Fu-Yun; Kuckelkorn, Jens; Liu, Di; Liu, Li-Qun; Pan, Xiao-Chuan

    2014-01-01

    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 CO 2 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

  9. Regional implications of heat flow of the Snake River Plain, Northwestern United States

    Science.gov (United States)

    Blackwell, D. D.

    1989-08-01

    The Snake River Plain is a major topographic feature of the Northwestern United States. It marks the track of an upper mantle and crustal melting event that propagated across the area from southwest to northeast at a velocity of about 3.5 cm/yr. The melting event has the same energetics as a large oceanic hotspot or plume and so the area is the continental analog of an oceanic hotspot track such as the Hawaiian Island-Emperor Seamount chain. Thus, the unique features of the area reflect the response of a continental lithosphere to a very energetic hotspot. The crust is extensively modified by basalt magma emplacement into the crust and by the resulting massive rhyolite volcanism from melted crustal material, presently occurring at Yellowstone National Park. The volcanism is associated with little crustal extension. Heat flow values are high along the margins of the Eastern and Western Snake River Plains and there is abundant evidence for low-grade geothermal resources associated with regional groundwater systems. The regional heat flow pattern in the Western Snake River Plains reflects the influence of crustal-scale thermal refraction associated with the large sedimentary basin that has formed there. Heat flow values in shallow holes in the Eastern Snake River Plains are low due to the Snake River Plains aquifer, an extensive basalt aquifer where water flow rates approach 1 km/yr. Below the aquifer, conductive heat flow values are about 100 mW m -2. Deep holes in the region suggest a systematic eastward increase in heat flow in the Snake River Plains from about 75-90 mW m -2 to 90-110 mW m -2. Temperatures in the upper crust do not behave similarly because the thermal conductivity of the Plio-Pleistocene sedimentary rocks in the west is lower than that in the volcanic rocks characteristic of the Eastern Snake River Plains. Extremely high heat loss values (averaging 2500 mW m -2) and upper crustal temperatures are characteristic of the Yellowstone caldera.

  10. Climate Change and Health Risks from Extreme Heat and Air Pollution in the Eastern United States

    Science.gov (United States)

    Limaye, V.; Vargo, J.; Harkey, M.; Holloway, T.; Meier, P.; Patz, J.

    2013-12-01

    Climate change is expected to exacerbate health risks from exposure to extreme heat and air pollution through both direct and indirect mechanisms. Directly, warmer ambient temperatures promote biogenic emissions of ozone precursors and favor the formation of ground-level ozone, while an anticipated increase in the frequency of stagnant air masses will allow fine particulates to accumulate. Indirectly, warmer summertime temperatures stimulate energy demand and exacerbate polluting emissions from the electricity sector. Thus, while technological adaptations such as air conditioning can reduce risks from exposures to extreme heat, they can trigger downstream damage to air quality and public health. Through an interdisciplinary modeling effort, we quantify the impacts of climate change on ambient temperatures, summer energy demand, air quality, and public health. The first phase of this work explores how climate change will directly impact the burden of heat-related mortality. Climatic patterns, demographic trends, and epidemiologic risk models suggest that populations in the eastern United States are likely to experience an increasing heat stress mortality burden in response to rising summertime air temperatures. We use North American Regional Climate Change Assessment Program modeling data to estimate mid-century 2-meter air temperatures and humidity across the eastern US from June-August, and quantify how long-term changes in actual and apparent temperatures from present-day will affect the annual burden of heat-related mortality across this region. With the US Environmental Protection Agency's Environmental Benefits Mapping and Analysis Program, we estimate health risks using concentration-response functions, which relate temperature increases to changes in annual mortality rates. We compare mid-century summertime temperature data, downscaled using the Weather Research and Forecasting model, to 2007 baseline temperatures at a 12 km resolution in order to estimate

  11. Loss of residual heat removal system: Diablo Canyon, Unit 2, April 10, 1987

    International Nuclear Information System (INIS)

    1987-06-01

    This report presents the findings of an NRC Augmented Inspection Team (AIT) investigation into the circumstances associated with the loss of residual heat removal (RHR) system capability for a period of approximately one and one-half hours at the Diablo Canyon, Unit 2 reactor facility on April 10, 1987. This event occurred while the Diablo Canyon, Unit 2, a pressurized water reactor, was shutdown with the reactor coolant system (RCS) water level drained to approximately mid-level of the hot leg piping. The reactor containment building equipment hatch was removed at the time of the event, and plant personnel were in the process of removing the primary side manways to gain access into the steam generator channel head areas. Thus, two fission product barriers were breached throughout the event. The RCS temperature increased from approximately 87 0 F to bulk boiling conditions without RCS temperature indication available to the plant operators. The RCS was subsequently pressurized to approximately 7 to 10 psig. The NRC AIT members concluded that the Diablo Canyon, Unit 2 plant was, at the time of the event, in a condition not previously analyzed by the NRC staff. The AIT findings from this event appear significant and generic to other pressurized water reactor facilities licensed by the NRC

  12. Studies on split heat pipe type adsorption ice-making test unit for fishing boats: Choice of heat pipe medium and experiments under unsteady heating sources

    International Nuclear Information System (INIS)

    Wang, L.W.; Wang, R.Z.; Lu, Z.S.; Chen, C.J.

    2006-01-01

    The split heat pipe type compound adsorption ice maker for fishing boats not only has the advantage of large volume cooling density but also has the advantage of less power consumption and high heat transfer performance. The available heat pipe media for the split heat pipe type compound adsorption ice maker, which are methanol, acetone and water are studied and compared in this paper, and the heat pipe medium of water shows the better performance for the reason of its stable heating and cooling process and high heat transfer performance. Considering the waste heat recovered from the diesel engine on fishing boats varies when the velocity of the fishing boat changes, the refrigeration performances at the condition of different values of heating power are studied while water is used as the heat pipe medium. Results show that the cooling power, as while as COP and SCP decrease when the heating power decreases. The highest COP and SCP are 0.41 and 731 W/kg, respectively, at the highest heating power of 4.2 kW, and the values decrease by 22% and 33%, respectively, when the heating power decreases by 15%. The values decrease by 32% and 51%, respectively, when the heating power decreases by 30%. The performance of the adsorption ice maker for the fishing boat with the 6160A type diesel engine is estimated, and the results show that the cooling power and ice productivity are as high as 5.44 kW and 1032 kg ice per day, respectively, even if the recovered waste heat decreases by 30% compared with the normal value. It can satisfy the ice requirements of such a fishing boat

  13. Experimental characterization, modeling and simulation of a wood pellet micro-combined heat and power unit used as a heat source for a residential building

    Energy Technology Data Exchange (ETDEWEB)

    Thiers, Stephane; Aoun, Bernard; Peuportier, Bruno [MINES ParisTech, CEP - Centre Energetique et Procedes, 60 Boulevard St Michel, 75272 Paris Cedex 06 (France)

    2010-06-15

    Cogeneration provides heat and power in a more efficient way than separate production. Micro-cogeneration (micro-CHP) is an emerging solution for the improvement of energy and environmental assessments of residential buildings. A wood pellet Stirling engine micro-CHP unit has been studied in order to characterize its annual performance when integrated to a building. First, through a test bench experiment, both transient and steady state behaviors of the micro-CHP unit have been characterized and modeled. Then a more complete model representing a hot water and heating system including the micro-CHP unit and a stratified storage tank has been carried out. This model has been coupled to a building model. A sensitivity analysis by simulation shows that the dimensioning of different elements of the system strongly influences its global energy performance. (author)

  14. Optimum Design of Heat Exchangers Networks Part-2: case study: Atmospheric Crude Distillation Unit

    International Nuclear Information System (INIS)

    Gabr, E.M.A.; EI-Temtamy, S.A.; Deriasl, S.F.; Moustafa, H.A.

    2004-01-01

    In this paper the computerized framework introduced in part-I for Heat Exchanger Network Synthesis (HENS) with optimality conditions of achieving the least operating and capital cost has been applied on an industrial atmospheric distillation unit existing in one of the Egyptian refineries . The application includes two types of designing: grass-root and revamp of the existing design. For the final grass-root design, the saving of utilities is 50% of the actual consumption while the net annual saving reaches 2,193,690 S/year .For revamping of existing design the % saving of hot and cold utilities are 38.1% and 43.2% respectively and the annual saving of 1,723,104 $/year is achieved

  15. Experimental investigation on AC unit integrated with sensible heat storage (SHS)

    Science.gov (United States)

    Aziz, N. A.; Amin, N. A. M.; Majid, M. S. A.; Hussin, A.; Zhubir, S.

    2017-10-01

    The growth in population and economy has increases the energy demand and raises the concerns over the sustainable energy source. Towards the sustainable development, energy efficiency in buildings has become a prime objective. In this paper, the integration of thermal energy storage was studied. This paper presents an experimental investigation on the performance of an air conditioning unit integrated with sensible heat storage (SHS) system. The results were compared to the conventional AC systems in the terms of average electricity usage, indoor temperature and the relative humidity inside the experimented room (cabin container). Results show that the integration of water tank as an SHS reduces the electricity usage by 5%, while the integration of well-insulated water tank saves up to 8% of the electricity consumption.

  16. Non-linear advanced control of the LHC inner triplet heat exchanger test unit

    International Nuclear Information System (INIS)

    Vinuela, E. Blanco; Cubillos, J. Casas; Prada Moraga, C. de; Cristea, S.

    2002-01-01

    The future Large Hadron Collider (LHC) at CERN will include eight interaction region final focus magnet systems, the so-called 'Inner Triplet', one on each side of the four beam collision points. The Inner Triplets will be cooled in a static bath of pressurized He II nominally at 1.9 K. This temperature is a control parameter and has very severe constraints in order to avoid the transition from the superconducting to normal resistive state. The main difference in these special zones with respect to a regular LHC cell is higher dynamic heat load unevenly distributed which modifies largely the process characteristics and hence the controller performance. Several control strategies have already been tested at CERN in a pilot plant (LHC String Test) which reproduced a LHC half-cell. In order to validate a common control structure along the whole LHC ring, a Nonlinear Model Predictive Control (NMPC) has been developed and implemented in the Inner Triplet Heat Exchanger Unit (IT-HXTU) at CERN. Automation of the Inner Triplet setup and the advanced control techniques deployed based on the Model Based Predictive Control (MBPC) principle are presented

  17. Stochastic Multicriteria Acceptability Analysis for Evaluation of Combined Heat and Power Units

    Directory of Open Access Journals (Sweden)

    Haichao Wang

    2014-12-01

    Full Text Available Combined heat and power (CHP is a promising technology that can contribute to energy efficiency and environmental protection. More CHP-based energy systems are planned for the future. This makes the evaluation and selection of CHP systems very important. In this paper, 16 CHP units representing different technologies are taken into account for multicriteria evaluation with respect to the end users’ requirements. These CHP technologies cover a wide range of power outputs and fuel types. They are evaluated from the energy, economy and environment (3E points of view, specifically including the criteria of efficiency, investment cost, electricity cost, heat cost, CO2 production and footprint. Uncertainties and imprecision are common both in criteria measurements and weights, therefore the stochastic multicriteria acceptability analysis (SMAA model is used in aiding this decision making problem. These uncertainties are treated better using a probability distribution function and Monte Carlo simulation in the model. Moreover, the idea of “feasible weight space (FWS” which represents the union of all preference information from decision makers (DMs is proposed. A complementary judgment matrix (CJM is introduced to determine the FWS. It can be found that the idea of FWS plus CJM is well compatible with SMAA and thus make the evaluation reliable.

  18. District space heating potential of low temperature hydrothermal geothermal resources in the southwestern United States. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    McDevitt, P.K.; Rao, C.R.

    1978-10-01

    A computer simulation model (GIRORA-Nonelectric) is developed to study the economics of district space heating using geothermal energy. GIRORA-Nonelectric is a discounted cashflow investment model which evaluates the financial return on investment for space heating. This model consists of two major submodels: the exploration for and development of a geothermal anomaly by a geothermal producer, and the purchase of geothermal fluid by a district heating unit. The primary output of the model is a calculated rate of return on investment earned by the geothermal producer. The results of the sensitivity analysis of the model subject to changes in physical and economic parameters are given in this report. Using the results of the economic analysis and technological screening criteria, all the low temperature geothermal sites in Southwestern United States are examined for economic viability for space heating application. The methodology adopted and the results are given.

  19. The critical role of extreme heat for maize production in the United States

    Science.gov (United States)

    Lobell, David B.; Hammer, Graeme L.; McLean, Greg; Messina, Carlos; Roberts, Michael J.; Schlenker, Wolfram

    2013-05-01

    Statistical studies of rainfed maize yields in the United States and elsewhere have indicated two clear features: a strong negative yield response to accumulation of temperatures above 30°C (or extreme degree days (EDD)), and a relatively weak response to seasonal rainfall. Here we show that the process-based Agricultural Production Systems Simulator (APSIM) is able to reproduce both of these relationships in the Midwestern United States and provide insight into underlying mechanisms. The predominant effects of EDD in APSIM are associated with increased vapour pressure deficit, which contributes to water stress in two ways: by increasing demand for soil water to sustain a given rate of carbon assimilation, and by reducing future supply of soil water by raising transpiration rates. APSIM computes daily water stress as the ratio of water supply to demand, and during the critical month of July this ratio is three times more responsive to 2°C warming than to a 20% precipitation reduction. The results suggest a relatively minor role for direct heat stress on reproductive organs at present temperatures in this region. Effects of elevated CO2 on transpiration efficiency should reduce yield sensitivity to EDD in the coming decades, but at most by 25%.

  20. Thermal performance evaluation of a latent heat storage unit for late evening cooking in a solar cooker having three reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Buddhi, D.; Sharma, A. [Devi Ahilya University, Indore (India). School of Energy and Environmental Studies, Thermal Energy Storage Laboratory; Sharma, S.D. [Mie University, Tsu (Japan). Faculty of Engineering, Department of Architecture

    2003-04-01

    In this paper, a phase change material (PCM) storage unit for a solar cooker was designed and developed to store energy during sunshine hours. The stored energy was utilised to cook food in the late evening. Commercial grade acetanilide (melting point 118.9 {sup o}C, latent heat of fusion 222 kJ/kg) was used as a latent heat storage material. Evening cooking experiments were conducted with different loads and loading times during the winter season. The experimental results showed that late evening cooking is possible in a solar cooker having three reflectors to enhance the incident solar radiation with the PCM storage unit. (author)

  1. Cernavoda NPP Unit 1: Ensuring heat sink at very low Danube river levels

    International Nuclear Information System (INIS)

    Urjan, D.

    2005-01-01

    Full text: On August 24, 2003 the summer heat wave has caused the Danube River to drop to its lowest level in more than a century, forcing a government commission of experts and a team of technical specialists from Cernavoda NPP to close Romania's unique nuclear reactor in operation at Cernavoda. The paper presents some of the required actions needed for plant shutdown and ensuring adequate fuel cooling at very low suction bay levels, due to the Danube River level drop (Danube waters cools the reactor). The water level in the Danube River at Cernavoda village, where the reactor is located, fell to a depth of less than three meters (10 feet) on Saturday, down from its usual level of almost seven meters (23 feet). Consequently, the Unit 1 nuclear power plant was shut down Sunday due to this record drought, which left insufficient water to cool down the reactor. Operating Instruction procedures were elaborated in order to provide a logical sequence of actions when the bay level decreases under 2.25 m, or the estimated level after 3 days will be lower than 1.8 m. When Raw Service Water (RSW) is lost, Recirculated Cooling Water (RCW) will remain in service only for Moderator, ESC, HT Pumps, HT Purification, D/C Cooler, LAC's, and D 2 O Feed Pump. Alternate water sources, like potable water and water from the fire protection system were taken in consideration in order to ensure heat sink to the RCW loads. At the same time, in case of total loss of Class III and Class IV Power, and Stand-By Diesel Generators unavailable because of the loss of heat sink provided by the RSW, Emergency Power System (EPS) was configured to supply directly the Class III Power 6 kV bus (BUG bus). Economical Impact According to a report, closing the nuclear plant costs Romania $500,000 a day. The total cost includes also losses due to a 40 percent reduction in hydroelectric power generation due to reduced river flow. The country had to cease power exports until the reactor comes back on line

  2. Active heat exchange system development for latent heat thermal energy storage

    Science.gov (United States)

    Lefrois, R. T.; Mathur, A. K.

    1980-01-01

    Five tasks to select, design, fabricate, test and evaluate candidate active heat exchanger modules for future applications to solar and conventional utility power plants were discussed. Alternative mechanizations of active heat exchange concepts were analyzed for use with heat of fusion phase change materials (PCMs) in the temperature range of 250 to 350 C. Twenty-six heat exchange concepts were reviewed, and eight were selected for detailed assessment. Two candidates were selected for small-scale experimentation: a coated tube and shell heat exchanger and a direct contact reflux boiler. A dilute eutectic mixture of sodium nitrate and sodium hydroxide was selected as the PCM from over 50 candidate inorganic salt mixtures. Based on a salt screening process, eight major component salts were selected initially for further evaluation. The most attractive major components in the temperature range of 250 to 350 C appeared to be NaNO3, NaNO2, and NaOH. Sketches of the two active heat exchange concepts selected for test are given.

  3. Development of a unit suitable for corrosion monitoring in district heating systems. Experiences with the LOCOR-cell test method

    DEFF Research Database (Denmark)

    Andersen, Asbjørn; Hilbert, Lisbeth Rischel

    2004-01-01

    A by-pass unit suitable for placement of a number of different probes for corrosion monitoring has been designed. Also measurements of water parameters are allowed in a side stream from the unit. The project is a part of the Nordic Innovation Fund project KORMOF. The by-pass unit has been installed...... in 6 pressurised circulating heating systems and in one cooling system. 7 different corrosion monitoring methods have been used to study corrosion rates and types in dependency of water chemistry. This paper describes the design of the by-pass unit including water analysis methods. It also describes...... the purpose, background and gained results of one of the used monitoring techniques, the crevice corrosion measurements obtained by the LOCOR-Cell„§. The crevice corrosion cell was developed by FORCE Technology in a previous district heating project financed by Nordic Industrial Fund (1)(2). Results from...

  4. Study of regeneration system of 300 MW power unit based on nondeaerating heat balance diagram at reduced load

    Science.gov (United States)

    Esin, S. B.; Trifonov, N. N.; Sukhorukov, Yu. G.; Yurchenko, A. Yu.; Grigor'eva, E. B.; Snegin, I. P.; Zhivykh, D. A.; Medvedkin, A. V.; Ryabich, V. A.

    2015-09-01

    More than 30 power units of thermal power stations, based on the nondeaerating heat balance diagram, successfully operate in the former Soviet Union. Most of them are power units with a power of 300 MW, equipped with HTGZ and LMZ turbines. They operate according to a variable electric load curve characterized by deep reductions when undergoing night minimums. Additional extension of the range of power unit adjustment makes it possible to maintain the dispatch load curve and obtain profit for the electric power plant. The objective of this research is to carry out estimated and experimental processing of the operating regimes of the regeneration system of steam-turbine plants within the extended adjustment range and under the conditions when the constraints on the regeneration system and its equipment are removed. Constraints concerning the heat balance diagram that reduce the power unit efficiency when extending the adjustment range have been considered. Test results are presented for the nondeaerating heat balance diagram with the HTGZ turbine. Turbine pump and feed electric pump operation was studied at a power unit load of 120-300 MW. The reliability of feed pump operation is confirmed by a stable vibratory condition and the absence of cavitation noise and vibration at a frequency that characterizes the cavitation condition, as well as by oil temperature maintenance after bearings within normal limits. Cavitation performance of pumps in the studied range of their operation has been determined. Technical solutions are proposed on providing a profitable and stable operation of regeneration systems when extending the range of adjustment of power unit load. A nondeaerating diagram of high-pressure preheater (HPP) condensate discharge to the mixer. A regeneration system has been developed and studied on the operating power unit fitted with a deaeratorless thermal circuit of the system for removing the high-pressure preheater heating steam condensate to the mixer

  5. 40 CFR 75.81 - Monitoring of Hg mass emissions and heat input at the unit level.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Monitoring of Hg mass emissions and... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Hg Mass Emission Provisions § 75.81 Monitoring of Hg mass emissions and heat input at the unit level. The owner or operator of the...

  6. Development of a new distillation unit combined with compressed heat pump (heat integrated distillation column (HIDiC)) (eco-energy city project)

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Toshinari; Aso, Kazumasa [Kimura Chemical Plants Co., Ltd., Amagasaki City, Hyogo (Japan); Takamatsu, Takeichiro [Research Inst. of Industrial Technology, Suita-City, Osaka (Japan); Nakaiwa, Masaru [National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan); Noda, Hideo; Kuratani, Nobuyuki [Kansai Chemical Engineearing Co., Ltd., Amagasaki-city, Hyogo (Japan); Yoshida, Kazufumi [Maruzen Petrochemical Co., Ltd., 25-10, Tokyo (Japan)

    1999-07-01

    To reduce the irreversible loss the Heat Integrated Distillation Column (HIDiC) is proposed by application of heat-pump technology. (Distillation column, which is an energy consuming separation unit, has been widely used in oil refinery and the other chemical-related plants. The reason why it is a major energy consumer is that a large amount of irreversible loss occurs in heat transfer within the process.) In this paper, current results on the study of HIDiC in both simulations and experiments are shown. HIDiC must be operated at a higher pressure in the rectifying section so as to make its temperature higher than that of the stripping section which stands parallel with the rectifying section. That makes heat transfer from the rectifying section to the stripping section. Because of vaporization in the stripping section and condensation in the rectifying section, the energy for the reboiler can be saved. The degree of energy saving can be expected to be much more than 30%, although the exact value depends on the characteristics of mixture to be separated. (The degree of energy saving is higher than the above, if the exhaust vapor from the HIDiC is used to heat the feed or the other processes.) To save energy by the HIDiC, high separation performances and heat transfer capabilities are required. It has been found out that the HIDiC, whose shape is like vertical shell and tube heat exchanger was enough to be practical use of the HIDiC from the static design principle points of view. (orig.)

  7. Behavior of copper corrosion products in water loops of heat-exchange units

    International Nuclear Information System (INIS)

    Zarembo, V.I.; Kritskii, V.G.; Slobodov, A.A.; Puchkov, L.V.

    1989-01-01

    This communication is dedicated to an examination of copper corrosion products (CP) in the conditions of real aqueous-chemical regime (ACR) parameters. The deposition of these CP in steam-generating zones (up to 85% of their total amount) stimulate local types of corrosion. The solubility in Cu CP (Cu 2 O, CuO, Cu(OH) 2 )-water (H 2 O)-gas (H 2 , O 2 )-conditioning additives (HCl, KOH) systems was determined by computer modeling according to the minimum Gibbs energy criterion on the basis of selected and matched thermodynamic constants for various chemical forms of copper under standard conditions. As a result of the authors' calculations they obtained the solubilities in water of CuO, Cu 2 O and Cu(OH) 2 when changing the dosage of active gases from 0 to 10 -2 mole/kg of water, of acid or equal to that of saturated vapor of pure water. Thus, they were able to monitor the behavior of copper CP in conditions modeling those of real ACR in operating heat exchange units, including in conditions deviating from the standard

  8. Optical Coating Performance and Thermal Structure Design for Heat Reflectors of JWST Electronic Control Unit

    Science.gov (United States)

    Quijada, Manuel A.; Threat, Felix; Garrison, Matt; Perrygo, Chuck; Bousquet, Robert; Rashford, Robert

    2008-01-01

    The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling system.

  9. Energy-Efficient Supermarket Heating, Ventilation, and Air Conditioning in Humid Climates in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    Supermarkets are energy-intensive buildings that consume the greatest amount of electricity per square foot of building of any building type in the United States and represent 5% of total U.S. commercial building primary energy use (EIA 2005). Refrigeration and heating, ventilation, and air-conditioning (HVAC) systems are responsible for a large proportion of supermarkets’ total energy use. These two systems sometimes work together and sometimes compete, but the performance of one system always affects the performance of the other. To better understand these challenges and opportunities, the Commercial Buildings team at the National Renewable Energy Laboratory investigated several of the most promising strategies for providing energy-efficient HVAC for supermarkets and quantified the resulting energy use and costs using detailed simulations. This research effort was conducted on behalf of the U.S. Department of Energy (DOE) Commercial Building Partnerships (CBP) (Baechler et al. 2012; Parrish et al. 2013; Antonopoulos et al. 2014; Hirsch et al. 2014). The goal of CBP was to reduce energy use in the commercial building sector by creating, testing, and validating design concepts on the pathway to net zero energy commercial buildings. Several CBP partners owned or operated buildings containing supermarkets and were interested in optimizing the energy efficiency of supermarket HVAC systems in hot-humid climates. These partners included Walmart, Target, Whole Foods Market, SUPERVALU, and the Defense Commissary Agency.

  10. Optimal coordinated scheduling of combined heat and power fuel cell, wind, and photovoltaic units in micro grids considering uncertainties

    International Nuclear Information System (INIS)

    Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein

    2016-01-01

    In this paper, a stochastic model is proposed for coordinated scheduling of combined heat and power units in micro grid considering wind turbine and photovoltaic units. Uncertainties of electrical market price; the speed of wind and solar radiation are considered using a scenario-based method. In the method, scenarios are generated using roulette wheel mechanism based on probability distribution functions of input random variables. Using this method, the probabilistic specifics of the problem are distributed and the problem is converted to a deterministic one. The type of the objective function, coordinated scheduling of combined heat and power, wind turbine, and photovoltaic units change this problem to a mixed integer nonlinear one. Therefore to solve this problem modified particle swarm optimization algorithm is employed. The mentioned uncertainties lead to an increase in profit. Moreover, the optimal coordinated scheduling of renewable energy resources and thermal units in micro grids increase the total profit. In order to evaluate the performance of the proposed method, its performance is executed on modified 33 bus distributed system as a micro grid. - Highlights: • Stochastic model is proposed for coordinated scheduling of renewable energy sources. • The effect of combined heat and power is considered. • Maximizing profits of micro grid is considered as objective function. • Considering the uncertainties of problem lead to profit increasing. • Optimal scheduling of renewable energy sources and thermal units increases profit.

  11. Evaluating the energy and CO2 emissions impacts of shifts in residential water heating in the United States

    International Nuclear Information System (INIS)

    Sanders, Kelly T.; Webber, Michael E.

    2015-01-01

    Water heating represented nearly 13% of 2010 residential energy consumption making it an important target for energy conservation efforts. The objective of this work is to identify spatially-resolved strategies for energy conservation, since little analysis has been done to identify how regional characteristics affect the energy consumed for water heating. We present a first-order thermodynamic analysis, utilizing ab initio calculations and regression methods, to quantify primary energy consumption and CO 2 emissions with regional specificity by considering by considering local electricity mixes, heat rates, solar radiation profiles, heating degrees days, and water heating unit sales for 27 regions of the US. Results suggest that shifting from electric towards natural gas or solar water heating offered primary energy and CO 2 emission reductions in most US regions, but these reductions varied considerably according to regional electricity mix and solar resources. We find that regions that would benefit most from technology transitions, are often least likely to switch due to limited economic incentives. Our results suggest that federal energy factor metrics, which ignore upstream losses in power generation, are insufficient in informing consumers about the energy performance of residential end use appliances. - Highlights: • US energy factor ratings for water heaters ignore upstream losses. • Switching from electric storage water heating reduces CO 2 emissions in most US regions. • Regions with greatest potential for CO 2 avoidance are least likely to shift technologies. • Benefits vary significantly according to climate and regional electricity fuel mix

  12. Application of intensified heat transfer for the retrofit of heat exchanger network

    International Nuclear Information System (INIS)

    Wang, Yufei; Pan, Ming; Bulatov, Igor; Smith, Robin; Kim, Jin-Kuk

    2012-01-01

    Highlights: → Novel design approach for the retrofit of HEN based on intensified heat transfer. → Development of a mathematical model to evaluate shell-and-tube heat exchanger performances. → Identification of the most appropriate heat exchangers requiring heat transfer enhancements in the heat exchanger network. -- Abstract: A number of design methods have been proposed for the retrofit of heat exchanger networks (HEN) during the last three decades. Although considerable potential for energy savings can be identified from conventional retrofit approaches, the proposed solutions have rarely been adopted in practice, due to significant topology modifications required and resulting engineering complexities during implementation. The intensification of heat transfer for conventional shell-and-tube heat exchangers can eliminate the difficulties of implementing retrofit in HEN which are commonly restricted by topology, safety and maintenance constraints, and includes high capital costs for replacing equipment and pipelines. This paper presents a novel design approach to solve HEN retrofit problems based on heat transfer enhancement. A mathematical model has been developed to evaluate shell-and-tube heat exchanger performances, with which heat-transfer coefficients and pressure drops for both fluids in tube and shell sides are obtained. The developed models have been compared with the Bell-Delaware, simplified Tinker and Wills-Johnston methods and tested with the HTRI (registered) and HEXTRAN (registered) software packages. This demonstrates that the new model is much simpler but can give reliable results in most cases. For the debottlenecking of HEN, four heuristic rules are proposed to identify the most appropriate heat exchangers requiring heat transfer enhancements in the HEN. The application of this new design approach allows a significant improvement in energy recovery without fundamental structural modifications to the network.

  13. Economic feasibility of heat supply from nuclear power plants in the United States

    International Nuclear Information System (INIS)

    Roe, K.K.; Oliker, I.

    1987-01-01

    Nuclear energy is regarded as competitive for urban district heating applications. Hot water heat transoport systems of up to 50 miles are feasible for heat loads over 1500 MWt, and heat load density of over 130 MWt/mi 2 is most suitable for nuclear applications. An incremental approach and a nuclear plant design provision for future heat extraction are recommended. Nuclear district heating technology status is discussed, particularly turbine design. Results of a study for retrofitting a major existing nuclear power plant to cogeneration operation are presented. The study indicates that for transmission distances up to 20 miles it is economical to generate and transport between 600 and 1200 MWt of district heat (author)

  14. Monitoring and understanding changes in heat waves, cold waves, floods, and droughts in the United States: State of knowledge

    Science.gov (United States)

    Peterson, Thomas C.; Heim, Richard R.; Hirsch, Robert M.; Kaiser, Dale P.; Brooks, Harold; Diffenbaugh, Noah S.; Dole, Randall M.; Giovannettone, Jason P.; Guirguis, Kristen; Karl, Thomas R.; Katz, Richard W.; Kunkel, Kenneth E.; Lettenmaier, Dennis P.; McCabe, Gregory J.; Paciorek, Christopher J.; Ryberg, Karen R.; K Wolter, BS Silva; Schubert, Siegfried; Silva, Viviane B. S.; Stewart, Brooke C.; Vecchia, Aldo V.; Villarini, Gabriele; Vose, Russell S.; Walsh, John; Wehner, Michael; Wolock, David; Wolter, Klaus; Woodhouse, Connie A.; Wuebbles, Donald

    2013-01-01

    Weather and climate extremes have been varying and changing on many different time scales. In recent decades, heat waves have generally become more frequent across the United States, while cold waves have been decreasing. While this is in keeping with expectations in a warming climate, it turns out that decadal variations in the number of U.S. heat and cold waves do not correlate well with the observed U.S. warming during the last century. Annual peak flow data reveal that river flooding trends on the century scale do not show uniform changes across the country. While flood magnitudes in the Southwest have been decreasing, flood magnitudes in the Northeast and north-central United States have been increasing. Confounding the analysis of trends in river flooding is multiyear and even multidecadal variability likely caused by both large-scale atmospheric circulation changes and basin-scale “memory” in the form of soil moisture. Droughts also have long-term trends as well as multiyear and decadal variability. Instrumental data indicate that the Dust Bowl of the 1930s and the drought in the 1950s were the most significant twentieth-century droughts in the United States, while tree ring data indicate that the megadroughts over the twelfth century exceeded anything in the twentieth century in both spatial extent and duration. The state of knowledge of the factors that cause heat waves, cold waves, floods, and drought to change is fairly good with heat waves being the best understood.

  15. Heat illness and death among workers - United States, 2012-2013.

    Science.gov (United States)

    Arbury, Sheila; Jacklitsch, Brenda; Farquah, Opeyemi; Hodgson, Michael; Lamson, Glenn; Martin, Heather; Profitt, Audrey

    2014-08-08

    Exposure to heat and hot environments puts workers at risk for heat stress, which can result in heat illnesses and death. This report describes findings from a review of 2012‒2013 Occupational Safety and Health Administration (OSHA) federal enforcement cases (i.e., inspections) resulting in citations under paragraph 5(a)(1), the "general duty clause" of the Occupational Safety and Health Act of 1970. That clause requires that each employer "furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees". Because OSHA has not issued a heat standard, it must use 5(a)(1) citations in cases of heat illness or death to enforce employers' obligations to provide a safe and healthy workplace. During the 2-year period reviewed, 20 cases of heat illness or death were cited for federal enforcement under paragraph 5(a)(1) among 18 private employers and two federal agencies. In 13 cases, a worker died from heat exposure, and in seven cases, two or more employees experienced symptoms of heat illness. Most of the affected employees worked outdoors, and all performed heavy or moderate work, as defined by the American Conference of Governmental Industrial Hygienists. Nine of the deaths occurred in the first 3 days of working on the job, four of them occurring on the worker's first day. Heat illness prevention programs at these workplaces were found to be incomplete or absent, and no provision was made for the acclimatization of new workers. Acclimatization is the result of beneficial physiologic adaptations (e.g., increased sweating efficiency and stabilization of circulation) that occur after gradually increased exposure to heat or a hot environment. Whenever a potential exists for workers to be exposed to heat or hot environments, employers should implement heat illness prevention programs (including acclimatization requirements) at their

  16. Quantity, Quality, and Availability of Waste Heat from United States Thermal Power Generation.

    Science.gov (United States)

    Gingerich, Daniel B; Mauter, Meagan S

    2015-07-21

    Secondary application of unconverted heat produced during electric power generation has the potential to improve the life-cycle fuel efficiency of the electric power industry and the sectors it serves. This work quantifies the residual heat (also known as waste heat) generated by U.S. thermal power plants and assesses the intermittency and transport issues that must be considered when planning to utilize this heat. Combining Energy Information Administration plant-level data with literature-reported process efficiency data, we develop estimates of the unconverted heat flux from individual U.S. thermal power plants in 2012. Together these power plants discharged an estimated 18.9 billion GJ(th) of residual heat in 2012, 4% of which was discharged at temperatures greater than 90 °C. We also characterize the temperature, spatial distribution, and temporal availability of this residual heat at the plant level and model the implications for the technical and economic feasibility of its end use. Increased implementation of flue gas desulfurization technologies at coal-fired facilities and the higher quality heat generated in the exhaust of natural gas fuel cycles are expected to increase the availability of residual heat generated by 10.6% in 2040.

  17. Heat balance calculation and feasibility analysis for initial startup of Fuqing nuclear turbine unit with non-nuclear steam

    International Nuclear Information System (INIS)

    He Liu; Xiao Bo; Song Yumeng

    2014-01-01

    Non-nuclear steam run up compared with nuclear steam run up, can verify the design, manufacture, installation quality of the unit, at the same time shorten the follow-up duration of the entire group ready to start debugging time. In this paper, starting from the first law of thermodynamics, Analyzed Heat balance Calculation and Feasibility analysis for Initial startup of Fuqing nuclear Turbine unit with Non-nuclear steam, By the above calculation, to the system requirements and device status on the basis of technical specifications, confirmed the feasibility of Non-nuclear steam running up in theory. After the implementation of the Non-nuclear turn of Fuqing unit, confirmed the results fit with the actual process. In summary, the Initial startup of Fuqing turbine unit with Non-nuclear steam is feasible. (authors)

  18. A novel algorithm for demand-control of a single-room ventilation unit with a rotary heat exchanger

    DEFF Research Database (Denmark)

    Smith, Kevin Michael; Jansen, Anders Lund; Svendsen, Svend

    in the indoor environment. Based on these values, a demand-control algorithm varies fan speeds to change airflow rates and varies the rotational speed of the heat exchanger to modulate heat and moisture recovery. The algorithm varies airflow rates to provide free cooling and limit CO2 concentrations and varies...... moisture recovery by varying the rotational speed and then safely unbalances airflows in a worst-case scenario. In the algorithm, frost protection and minimum supply temperature take the highest priority and override other controls. This paper documents the proposed demand control algorithm and analyses...... its impacts on compliance of building regulations in Denmark. The paper presents an algorithm that manufacturers can program into their controls. The commercially available single-room ventilation unit with a rotary heat exchanger uses this algorithm coded in the C language. Future work will document...

  19. Comparison of Advanced Residential Water Heating Technologies in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, J.; Fang, X.; Wilson, E.

    2013-05-01

    Gas storage, gas tankless, condensing, electric storage, heat pump, and solar water heaters were simulated in several different climates across the US installed in both conditioned and unconditioned space and subjected to several different draw profiles. While many preexisting models were used, new models of condensing and heat pump water heaters were created specifically for this work.

  20. Experimental analysis of an air-to-air heat recovery unit for balanced ventilation systems in residential buildings

    International Nuclear Information System (INIS)

    Fernandez-Seara, Jose; Diz, Ruben; Uhia, Francisco J.; Dopazo, Alberto; Ferro, Jose M.

    2011-01-01

    This paper deals with the experimental analysis of an air-to-air heat recovery unit equipped with a sensible polymer plate heat exchanger (PHE) for balanced ventilation systems in residential buildings. The PHE is arranged in parallel triangular ducts. An experimental facility was designed to reproduce the typical outdoor and exhaust air conditions with regard to temperature and humidity. The unit was tested under balanced operation conditions, as commonly used in practice. A set of tests was conducted under the reference operating conditions to evaluate the PHE performance. Afterwards, an experimental parametric analysis was conducted to investigate the influence of changing the operating conditions on the PHE performance. Experiments were carried out varying the inlet fresh air temperature, the exhaust air relative humidity and the air flow rate. The experimental results are shown and discussed in this paper.

  1. Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Xun Yang

    2017-08-01

    Full Text Available In this study, the dynamic melting process of the phase change material (PCM in a vertical cylindrical tube-in-tank thermal energy storage (TES unit was investigated through numerical simulations and experimental measurements. To ensure good heat exchange performance, a concentric helical coil was inserted into the TES unit to pipe the heat transfer fluid (HTF. A numerical model using the computational fluid dynamics (CFD approach was developed based on the enthalpy-porosity method to simulate the unsteady melting process including temperature and liquid fraction variations. Temperature measurements using evenly spaced thermocouples were conducted, and the temperature variation at three locations inside the TES unit was recorded. The effects of the HTF inlet parameters were investigated by parametric studies with different temperatures and flow rate values. Reasonably good agreement was achieved between the numerical prediction and the temperature measurement, which confirmed the numerical simulation accuracy. The numerical results showed the significance of buoyancy effect for the dynamic melting process. The system TES performance was very sensitive to the HTF inlet temperature. By contrast, no apparent influences can be found when changing the HTF flow rates. This study provides a comprehensive solution to investigate the heat exchange process of the TES system using PCM.

  2. Micro-cogeneration units based on Stirling engine for heating and their real operation

    Science.gov (United States)

    Čierny, Jaroslav; Patsch, Marek

    2014-08-01

    This article was deal with micro-cogeneration units based on Stirling engine. We watched problematic of real working Stirling engine. The article also contain hookup of unit constructed at University of Zilina.

  3. A variant of the dynamic programming algorithm for unit commitment of combined heat and power systems

    DEFF Research Database (Denmark)

    Rong, Aiying; Hakonen, Henri; Lahdelma, Risto

    2008-01-01

    introduce in this paper the DP-RSC1 algorithm, which is a variant of the dynamic programming (DP) algorithm based on linear relaxation of the ON/OFF states of the units and sequential commitment of units one by one. The time complexity of DP-RSC1 is proportional to the number of generating units...

  4. Evaluation of European District Heating Systems for Application to Army Installations in the United States

    Science.gov (United States)

    2006-07-01

    of the conurbation, the effectiveness of the investments as well as the plant’s management and the owner’s return requirements ( Energia 2004...37 p. Design Manual of ThermoNet Systems. 32 p. (In Finnish). ECONET Manual. 2005. Fläktwoods. Energia 2004. Energy year 2004. “District Heating...Pulliainen, K. 2005. Helsingin Energia . Oral source. Seppänen, O. 1995. ISBN 951-97233-1-5. Heating of Buildings. Publisher Suomen LVI- yhdistyken

  5. Complementary-relationship-based 30 year normals (1981-2010) of monthly latent heat fluxes across the contiguous United States

    Science.gov (United States)

    Szilagyi, Jozsef

    2015-11-01

    Thirty year normal (1981-2010) monthly latent heat fluxes (ET) over the conterminous United States were estimated by a modified Advection-Aridity model from North American Regional Reanalysis (NARR) radiation and wind as well as Parameter-Elevation Regressions on Independent Slopes Model (PRISM) air and dew-point temperature data. Mean annual ET values were calibrated with PRISM precipitation (P) and validated against United States Geological Survey runoff (Q) data. At the six-digit Hydrologic Unit Code level (sample size of 334) the estimated 30 year normal runoff (P - ET) had a bias of 18 mm yr-1, a root-mean-square error of 96 mm yr-1, and a linear correlation coefficient value of 0.95, making the estimates on par with the latest Land Surface Model results but without the need for soil and vegetation information or any soil moisture budgeting.

  6. Analysis of loss of decay heat removal sequences at Browns Ferry Unit One: Chapter 17

    International Nuclear Information System (INIS)

    Harrington, R.M.

    1983-01-01

    This paper summarizes the Oak Ridge National Laboratory (ORNL) report ''Loss of DHR Sequences at Browns Ferry Unit One - Accident Sequence Analysis'' (NUREG/CR-2973). The Loss of DHR investigation is the third in a series of accident studies concerning the BWR 4 - MK I containment plant design. These studies, sponsored by the Nuclear Regulatory Commission Severe Accident Sequence Analysis (SASA) program, have been conducted at ORNL with the full cooperation of the Tennessee Valley Authority (TVA), using Unit One of the Browns Ferry Nuclear Plant as the model design. Each unit of this three-unit plant has a maximum authorized power of 3293 MW(t) or 1067 net MW(e). The primary containments are of the Mark I pressure suppression pool type and the three units share a secondary containment of the controlled leakage, elevated release design. Each unit occupies a separate reactor building located in one structure underneath the common refueling floor

  7. Differences in Heat-Related Mortality by Citizenship Status: United States, 2005-2014.

    Science.gov (United States)

    Taylor, Ethel V; Vaidyanathan, Ambarish; Flanders, W Dana; Murphy, Matthew; Spencer, Merianne; Noe, Rebecca S

    2018-04-01

    To determine whether non-US citizens have a higher mortality risk of heat-related deaths than do US citizens. We used place of residence reported in mortality data from the National Vital Statistics System from 2005 to 2014 as a proxy for citizenship to examine differences in heat-related deaths between non-US and US citizens. Estimates from the US Census Bureau American Community Survey of self-reported citizenship status and place of birth provided the numbers for the study population. We calculated the standardized mortality ratio and relative risk for heat-related deaths between non-US and US citizens nationally. Heat-related deaths accounted for 2.23% (n = 999) of deaths among non-US citizens and 0.02% (n = 4196) of deaths among US citizens. The age-adjusted standardized mortality ratio for non-US citizens compared with US citizens was 3.4 (95% confidence ratio [CI] = 3.2, 3.6). This risk was higher for Hispanic non-US citizens (risk ratio [RR] = 3.6; 95% CI = 3.2, 3.9) and non-US citizens aged 18 to 24 years (RR = 20.6; 95% CI = 16.5, 25.7). We found an increased mortality risk among non-US citizens compared with US citizens for heat-related deaths, especially those younger and of Hispanic ethnicity.

  8. The epidemiology of occupational heat exposure in the United States: a review of the literature and assessment of research needs in a changing climate

    Science.gov (United States)

    Gubernot, Diane M.; Anderson, G. Brooke; Hunting, Katherine L.

    2014-10-01

    In recent years, the United States has experienced record-breaking summer heat. Climate change models forecast increasing US temperatures and more frequent heat wave events in the coming years. Exposure to environmental heat is a significant, but overlooked, workplace hazard that has not been well-characterized or studied. The working population is diverse; job function, age, fitness level, and risk factors to heat-related illnesses vary. Yet few studies have examined or characterized the incidence of occupational heat-related morbidity and mortality. There are no federal regulatory standards to protect workers from environmental heat exposure. With climate change as a driver for adaptation and prevention of heat disorders, crafting policy to characterize and prevent occupational heat stress for both indoor and outdoor workers is increasingly sensible, practical, and imperative.

  9. Development of a method for calculating steady-state equipment sensible heat ratio of direct expansion air conditioning units

    International Nuclear Information System (INIS)

    Xia Liang; Chan, M.Y.; Deng Shiming

    2008-01-01

    A complete set of calculation method for steady-state equipment sensible heat ratio (SHR) for a direct expansion (DX) cooling coil has been developed and reported. The method was based on the fundamentals of energy conservation and heat and mass transfer taking place in the DX cooling coil, and was experimentally validated using an experimental DX A/C rig. With the method developed, the effect of refrigerant evaporating temperature at fixed inlet air conditions on equipment SHR has been theoretically analyzed. The validated method can be useful in further studying the inherent operating characteristics of a DX air conditioning (A/C) unit and in developing suitable control strategies for achieving higher energy efficiency and better indoor thermal environment

  10. Metallurgical investigation of cracking of the isolation valve downstream piping of regenerative heat exchanger at beaver valley unit 1 station

    International Nuclear Information System (INIS)

    Rao, G.V.

    1998-01-01

    A metallurgical investigation was conducted to establish the mechanism and cause of cracking in the regenerative heat exchanger piping at Beaver Valley Unit 1 PWR station in the USA. The investigation, which was centered on an eight inch long pipe section containing the cracking included surface examinations, metallographic and fractographic examinations, and chemistry evaluations. The results of the examinations showed that there were two types of pipe degradation mechanisms that affected the type 304 stainless schedule 40 piping. These consisted of localized corrosive attack on the OD surface due to the presence of chlorides, sulphates and phosphates, and transgranular stress corrosion cracking in the pipe wall due to the presence of chloride contaminants. The overall results of the investigation showed that the introduction of contaminants from external sources other than pipe insulation was the cause of heat exchanger pipe cracking. (author)

  11. Economic and policy factors driving adoption of institutional woody biomass heating systems in the United States

    Science.gov (United States)

    Jesse D. Young; Nathaniel M. Anderson; Helen T. Naughton; Katrina Mullan

    2018-01-01

    Abundant stocks of woody biomass that are associated with active forest management can be used as fuel for bioenergy in many applications. Though factors driving large-scale biomass use in industrial settings have been studied extensively, small-scale biomass combustion systems commonly used by institutions for heating have received less attention. A zero inflated...

  12. Parameter effect of a phase change thermal energy storage unit with one shell and one finned tube on its energy efficiency ratio and heat storage rate

    International Nuclear Information System (INIS)

    Wang, Wei-Wei; Wang, Liang-Bi; He, Ya-Ling

    2016-01-01

    Highlights: • The parameter effect on the performance of PCTES unit using fins is reported. • The configurations of PCTES unit using fins in optimum performance are suggested. • Two parameters to indicate the effects of PCM and tube material properties are found. • The working conditions of PCTES unit using fins in optimum performance are analyzed. - Abstract: The performance of a phase change thermal energy storage (PCTES) unit using circular finned tube is affected by many parameters. Thorough studies of the parameter effect on the performance of PCTES unit are strongly required in its optimum design process. Based on a reported energy efficiency ratio and a newly defined parameter named the heat storage rate, the parameter effect on the performance of PCTES unit using circular finned tube is numerically investigated. When the fin pitch is greater than 4 times of the inner radius of the tube, the fin height and the fin thickness have little effect on the energy efficiency ratio and the heat storage rate. When the fin pitch is small, the performance of PCTES unit becomes better using large fin height and width. The energy efficiency ratio and the heat storage rate are more sensitive to the outer tube diameter. The performance of PCTES unit using circular finned tube is best when water is used as the heat transfer fluid (HTF). When the fluid flow of HTF is in a laminar state, the energy efficiency ratio and the heat storage rate are larger than that in a turbulent state.

  13. Heat Transfer Reactor Experiment (HTRE)-3 Container Storage Unit Resource Conservation Recovery Act closure plan

    International Nuclear Information System (INIS)

    Spry, M.J.

    1992-11-01

    This document describes the closure of the HTRE-3 Container Storage Unit under the requirements of the Resource Conservation and Recovery Act. The unit's location, size, history, and current status are described. The document also summarizes the decontamination and decommissioning efforts performed in 1983 and provides an estimate of,waste residues remaining in the HTRE-3 assembly. A risk evaluation was performed that demonstrates that the residue does not pose a hazard to public health or the environment. Based on the risk evaluation, it is proposed that the HTRE-3 Container Storage Unit be closed in its present condition, without further decontamination or removal activities

  14. Fundamental research on the gravity assisted heat pipe thermal storage unit (GAHP-TSU) with porous phase change materials (PCMs) for medium temperature applications

    International Nuclear Information System (INIS)

    Hu, Bo-wen; Wang, Qian; Liu, Zhen-Hua

    2015-01-01

    Highlights: • A novel gravity-assisted heat pipe thermal storage unit (GAHP-TSU) is presented and tested. • Composite granular solid–liquid PCM is piled up as the porous medium layer in GAHP-TSU. • GAHP-TSU avoids the major obstacle of low thermal conductivity of the PCM. • GAHP-TSU enables the thermal storage unit with outstanding heat transfer performance. - Abstract: In this study, a novel gravity-assisted heat pipe type thermal storage unit (GAHP-TSU) has been presented for the potential application in solar air conditioning and refrigeration systems, in which composite granular solid–liquid PCMs compounded by RT100 and high-density polyethylene with phase change temperature of 100 °C are piled up as a porous PCMs medium layer. Water is used as heat transfer fluid in the GAHP-TSU. The heat transfer mechanism of heat storage/release in the GAHP-TSU is similar to that of the gravity-assisted heat pipe, which is superior to traditional direct-contact or indirect-contact thermal storage units. The properties of start-up, heat transfer characteristics on the stages of heat absorption and release of the GAHP-TSU are studied in detailed, including necessary calculations based on heat transfer theory. The results show that the whole system is almost isothermal at the temperature over 70 °C and the heat transfer properties are excellent both for heat absorption and release stages. The GAHP-TSU device with low thermal conductivity of the PCMs is promising in potential industry applications

  15. Performance of double source boiler with coal-fired and solar power tower heat for supercritical power generating unit

    International Nuclear Information System (INIS)

    Zhang, Maolong; Du, Xiaoze; Pang, Liping; Xu, Chao; Yang, Lijun

    2016-01-01

    An approach of high-efficiency utilization of solar energy was proposed, by which the high concentrated heat received by the solar tower was integrated to the supercritical coal-fired boiler. Two schemes that solar energy was used to heat superheat steam or subcooled feed water were presented. The thermodynamic and heat transfer models were established. For a practical 660 MW supercritical power generating unit, the standard coal consumption of power generation could be decreased by more than 17 g/kWh by such double source boiler. The drawbacks of both schemes were found and then were amended by adding a flue gas bypass to the boiler. It also can be concluded that the maximum solar contribution of two schemes for the gross power generation are 6.11% and 4.90%, respectively. The solar power efficiency of the re-modified designs were demonstrated be superior to that of PS10. In terms of turbine efficiency, the comparisons with Solar Two plant having similar initial temperature found that the efficiency of Scheme I was 5.25% higher than that of Solar Two while the advantage of Scheme II was existing either. Additionally, in two schemes with flue bypass when the medium was extracted, the thermal efficiency of boiler could be improved as well. - Highlights: • High concentrated solar tower heat is integrated to the supercritical coal-fired boiler. • The double source boiler can use solar energy to heat superheat steam or subcooled feed water. • Power generating coal consumption can be reduced by more than 17 g/kWh by the double source boiler. • The solar contribution of double source boiler for the gross power generation can be as high as 6.11%.

  16. Stochastic PSO-based heat and power dispatch under environmental constraints incorporating CHP and wind power units

    Energy Technology Data Exchange (ETDEWEB)

    Piperagkas, G.S.; Anastasiadis, A.G.; Hatziargyriou, N.D. [National Technical University of Athens, School of Electrical and Computer Engineering, Electric Power Division, 9, Iroon Polytechneiou Str., GR-15773 Zografou, Athens (Greece)

    2011-01-15

    In this paper an extended stochastic multi-objective model for economic dispatch (ED) is proposed, that incorporates in the optimization process heat and power from CHP units and expected wind power. Stochastic restrictions for the CO{sub 2}, SO{sub 2} and NO{sub x} emissions are used as inequality constraints. The ED problem is solved using a multi-objective particle swarm optimization technique. The available wind power is estimated from a transformation of the wind speed considered as a random variable to wind power. Simulations are performed on the modified IEEE 30 bus network with 2 cogeneration units and actual wind data. Results concerning minimum cost and emissions reduction options are finally drawn. (author)

  17. Initial Investigation into the Potential of CSP Industrial Process Heat for the Southwest United States

    Energy Technology Data Exchange (ETDEWEB)

    Kurup, Parthiv [National Renewable Energy Lab. (NREL), Golden, CO (United States); Turchi, Craig [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-11-01

    After significant interest in the 1970s, but relatively few deployments, the use of solar technologies for thermal applications, including enhanced oil recovery (EOR), desalination, and industrial process heat (IPH), is again receiving global interest. In particular, the European Union (EU) has been a leader in the use, development, deployment, and tracking of Solar Industrial Process Heat (SIPH) plants. The objective of this study is to ascertain U.S. market potential of IPH for concentrating collector technologies that have been developed and promoted through the U.S. Department of Energy's Concentrating Solar Power (CSP) Program. For this study, the solar-thermal collector technologies of interest are parabolic trough collectors (PTCs) and linear Fresnel (LF) systems.

  18. Heat Release Rate of an Open Kitchen Fire of Small Residential Units in Tall Buildings

    OpenAIRE

    Chow, W.K.

    2014-01-01

    Many small units of area less than 30 m2 in residential buildings over 200 m tall are equipped with open kitchens in Asia, including Hong Kong. Fire safety provisions of these kitchens are determined by performance-based design (PBD). In most PBD projects, only the spread of smoke from the kitchen on fire to the outside was commonly studied. However, a fire load survey in Hong Kong indicated large quantities of combustibles are stored in residential units. Cooking oil was found to be ignited ...

  19. Break-Even Cost for Residential Solar Water Heating in the United States: Key Drivers and Sensitivities

    Energy Technology Data Exchange (ETDEWEB)

    Cassard, H.; Denholm, P.; Ong, S.

    2011-02-01

    This paper examines the break-even cost for residential rooftop solar water heating (SWH) technology, defined as the point where the cost of the energy saved with a SWH system equals the cost of a conventional heating fuel purchased from the grid (either electricity or natural gas). We examine the break-even cost for the largest 1,000 electric and natural gas utilities serving residential customers in the United States as of 2008. Currently, the break-even cost of SWH in the United States varies by more than a factor of five for both electricity and natural gas, despite a much smaller variation in the amount of energy saved by the systems (a factor of approximately one and a half). The break-even price for natural gas is lower than that for electricity due to a lower fuel cost. We also consider the relationship between SWH price and solar fraction and examine the key drivers behind break-even costs. Overall, the key drivers of the break-even cost of SWH are a combination of fuel price, local incentives, and technical factors including the solar resource location, system size, and hot water draw.

  20. An improved unit decommitment algorithm for combined heat and power systems

    DEFF Research Database (Denmark)

    Rong, Aiying; Lahdelma, R.; Grunow, Martin

    2009-01-01

    can decommit (switch off) the least cost-efficient plants properly. The improved initial solution for the committed plants is generated by a heuristic procedure. The heuristic procedure utilizes both the Lagrangian relaxation principle that relaxes the system-wide (heat and power) demand constraints...... cases. The maximum improvement is 11.3% and the maximum degradation is only 0.04% (only two sub-cases out of 216 sub-cases) with an average improvement of 0.3-0.5%, for different planning horizons. Moreover, IUD is more efficient (1.1-3 times faster on average) than UD. (C) 2008 Elsevier B.V. All rights...

  1. Heat and Molecules. Seychelles Integrated Science. [Teacher and Pupil Booklets]. Unit 10.

    Science.gov (United States)

    Brophy, M.; Fryars, M.

    Seychelles Integrated Science (SIS), a 3-year laboratory-based science program for students (ages 11-15) in upper primary grades 7, 8, and 9, was developed from an extensive evaluation and modification of previous P7-P9 materials. This P8 SIS unit deals with: (1) changes in temperature which make matter expand and contract (and how this affects…

  2. Simple equation for estimating actual evapotranspiration using heat units for wheat in arid regions

    Directory of Open Access Journals (Sweden)

    M.A. Salama

    2015-07-01

    Application of treatment (B resulted in highly significant increase in yield production of Gemmeza10 and Misr2 as compared to treatment (A. Grain yield of different wheat varieties grown under treatment (B could be ranked in the following descending order: Misr2 > Gemmeza10 > Sids12. While under treatment (A it could be arranged in the following descending order: Misr2 > Sids12 > Gemmeza10. On the other hand, the overall means indicated non-significant difference between all wheat verities. The highest values of water and irrigation use efficiency as well as heat use efficiency were obtained with treatment (B. The equation used in the present study is available to estimate ETa under arid climate with drip irrigation system.

  3. Environmental compatibility of biogas operated combined heat and power units in practice; Umweltvertraeglichkeit biogasbetriebener Blockheizkraftwerke in der Praxis

    Energy Technology Data Exchange (ETDEWEB)

    Aschmann, V.; Kissel, R.; Gronauer, A. [Bayerische Landesanstalt fuer Landwirtschaft (LfL), Freising (Germany). Inst. fuer Landtechnik und Tierhaltung

    2008-07-01

    Since the amendment of the Renewable Energies Act the number of start-ups of new biogas plants increased substantially. For a sustainable and environmentally friendly power production the output of pollutants is to be minimized. Under this aspect, the authors of the contribution under consideration report on investigations at six biogas operated combined heat and power units on agricultural biogas facilities. The limit values of exhaust gas relative to nitrogen oxides cannot be kept during operation at full load. A falling below of the limit value can be achieved only under acceptance of losses of the efficiency and simultaneous increase of the portion of unburned hydrocarbons in the exhaust gas. There is a direct connection between the reduction of the concentration of nitrogen oxides and the output quantity of hydrocarbons.

  4. Bone heat generated using conventional implant drills versus piezosurgery unit during apical cortical plate perforation.

    Science.gov (United States)

    Lajolo, Carlo; Valente, Nicola Alberto; Romandini, William Giuseppe; Petruzzi, Massimo; Verdugo, Fernando; D'Addona, Antonio

    2018-03-09

    The apical portion of the implant osteotomy receives less irrigation and cooling during surgical preparation. High bone temperatures, above the critical 10°C threshold, may impair osseointegration, particularly, around dense cortical bone. The aim of this study is to evaluate the apical cortical plate temperature increase with two different devices and pressure loads in a porcine rib ex-vivo model. Twenty-four implant sites were prepared on porcine ribs divided into 4 groups of 6 samples each according to the device used (conventional drill system or piezosurgery) and pressure load applied (1000 g or 1500 g). A rubber dam was used to isolate the apical cortical plate from the cooling effect of irrigation. Temperature variation measurements were taken using an infrared thermometer. The piezosurgery unit was 2 times more likely to increase the osteotomy temperature by 10.0°C (OR = 2; 95% CI = 1.136-3.522; p piezosurgery-1000 g) and 8.17°C (SD = 6.12) for group 4 (piezosurgery-1,500 g). The piezosurgery site preparation caused significantly higher temperature increase than conventional drills (p piezosurgery unit is a potential risk during implant site preparation. The piezosurgical device reached significantly higher temperatures than conventional drilling at the apical cortical portion of the osteotomy. The temperature increase is often higher than the critical 10°C threshold. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  5. Optimal stochastic coordinated scheduling of proton exchange membrane fuel cell-combined heat and power, wind and photovoltaic units in micro grids considering hydrogen storage

    International Nuclear Information System (INIS)

    Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein

    2017-01-01

    Highlights: •Stochastic model is proposed for coordinated scheduling of renewable energy sources. •The effect of combined heat and power is considered. •Hydrogen storage is considered for fuel cells. •Maximizing profits of micro grid is considered as objective function. •Considering the uncertainties of problem lead to profit increasing. -- Abstract: Nowadays, renewable energy sources and combined heat and power units are extremely used in micro grids, so it is necessary to schedule these units to improve the performance of the system. In this regard, a stochastic model is proposed in this paper to schedule proton exchange membrane fuel cell-combined heat and power, wind turbines, and photovoltaic units coordinately in a micro grid while considering hydrogen storage. Hydrogen storage strategy is considered for the operation of proton exchange membrane fuel cell-combined heat and power units. To consider stochastic generation of renewable energy source units in this paper, a scenario-based method is used. In this method, the uncertainties of electrical market price, the wind speed, and solar irradiance are considered. This stochastic scheduling problem is a mixed integer- nonlinear programming which considers the proposed objective function and variables of coordinated scheduling of PEMFC-CHP, wind turbines and photovoltaic units. It also considers hydrogen storage strategy and converts it to a mixed integer nonlinear problem. In this study a modified firefly algorithm is used to solve the problem. This method is examined on modified 33-bus distributed network as a MG for its performance.

  6. Water from abandoned mines as a heat source: practical experiences of open- and closed-loop strategies, United Kingdom

    OpenAIRE

    Banks, D; Athresh, A; Al-Habaibeh, A; Burnside, N

    2017-01-01

    Pilot heat pump systems have been installed at two former collieries in Yorkshire/Derbyshire, England, to extract heat from mine water. The installations represent three fundamental configurations of heat exchanger. At Caphouse Colliery, mine water is pumped through a heat exchanger coupled to a heat pump and then discharged to waste (an open-loop heat exchange system). The system performs with high thermal efficiency, but the drawbacks are: (1) it can only be operated when mine water is bein...

  7. Combined heat and power unit using renewable raw materials. A cogeneration power plant with wood chips and pellets; BHKW auf Basis nachwachsender Rohstoffe. KWK mit Holzhackschnitzeln und Pellets

    Energy Technology Data Exchange (ETDEWEB)

    Lennartz, Marc Wilhelm

    2013-07-15

    The combined heat and power units of the next generation operate with renewable resources. The plants working with wood chips or pellets now are ready for mass production. So, farmers and foresters, trade and municipalities may pile in the decentralized, energetic self-sufficiency. Two companies have developed procedures with which combined heat and power plants based can be operated on wood chips or pellets.

  8. Analysis of the use of waste heat obtained from coal-fired units in Organic Rankine Cycles and for brown coal drying

    International Nuclear Information System (INIS)

    Łukowicz, Henryk; Kochaniewicz, Andrzej

    2012-01-01

    The ever-increasing restrictions on greenhouse gas emissions have created a need for new energy technologies. One way to meet these new requirements is to optimise the efficiency of power units. This paper presents two energy technologies that, if used, will increase the efficiency of electricity generation. One of the most effective ways to improve the efficiency of brown coal-fired units is by drying the coal that is fed into the boiler. Here, we describe a technology that uses the waste heat obtained from exhaust gases. This paper also presents an analysis of the feasibility of and potential for using waste heat obtained from exhaust gases to feed Organic Rankine Cycles (ORCs). Several low-temperature working fluids were considered, which were selected based on properties that were best suited for these types of cycles. The impact of these working fluids on the efficiency and capacity of the ORC was also examined. The calculations for ORCs fed with waste heat obtained from exhaust gases from hard coal- and brown coal-fired boilers were compared. -- Highlights: ► We describe a technology that uses the waste heat obtained from exhaust gases. ► The impact of using different working fluids with a low boiling point is examined. ► We describe integrating the ORC with the power unit. ► The use of waste heat from boiler exhaust gases to dry brown coal is proposed. ► We demonstrate a possible increase in power unit efficiency.

  9. Selection of cooling fluid for an organic Rankine cycle unit recovering heat on a container ship sailing in the Arctic region

    DEFF Research Database (Denmark)

    Suárez de la Fuente, Santiago; Larsen, Ulrik; Pierobon, Leonardo

    2017-01-01

    As Arctic sea ice coverage declines it is expected that marine traffic could increase in this northern region due to shorter routes. Navigating in the Arctic offers opportunities and challenges for waste heat recovery systems (WHRS). Lower temperatures require larger heating power on board, hence...... air as coolant. This paper explores the use of two different coolants, air and seawater, for an organic Rankine cycle (ORC) unit using the available waste heat in the scavenge air system of a container ship navigating in Arctic Circle. Using a two-step single objective optimisation process, detailed...

  10. A study of the reverse cycle defrosting performance on a multi-circuit outdoor coil unit in an air source heat pump – Part I: Experiments

    International Nuclear Information System (INIS)

    Qu, Minglu; Xia, Liang; Deng, Shiming; Jiang, Yiqiang

    2012-01-01

    Highlights: ► We experimental study the defrosting performance on a multi-circuit outdoor coil unit in an ASHP unit. ► We find that defrosting is quicker on the airside of upper circuits than that on the lower circuits. ► We discuss the effects of downwards flowing of the melted frost along the outdoor coil surface on defrosting performance. -- Abstract: When an air source heat pump (ASHP) unit operates in heating mode, frost can be accumulated on the surface of its finned outdoor coil which normally has multiple parallel circuits on its refrigerant side for minimized refrigerant pressure loss and enhanced heat transfer efficiency. On its airside, however, there is usually no segmentation corresponding to the number of refrigerant circuit. Frosting deteriorates the operation and energy efficiency of the ASHP unit and periodic defrosting becomes necessary. Currently the most widely used standard defrosting method for ASHPs is reverse cycle defrost. This paper, the first part of a two-part series, reports on the experimental part of a study of the reverse cycle defrosting performance on a multi-circuit outdoor coil unit in an experimental 6.5 kW heating capacity residential ASHP unit. Firstly the experimental ASHP unit is described and experimental procedures detailed. Secondly, the experimental results are reported. This is followed by the discussion on the effects of downwards flowing of the melted frost along a multi-circuit outdoor coil surface on defrosting performance. Finally, the evaluation of the defrosting efficiency for the experimental ASHP unit is provided. In the second part of the series, a modeling analysis on the effects of downwards flowing of the melted frost along the multi-circuit outdoor coil surface on defrosting performance of the experimental ASHP unit will be presented.

  11. Heat Maps of Hypertension, Diabetes Mellitus, and Smoking in the Continental United States.

    Science.gov (United States)

    Loop, Matthew Shane; Howard, George; de Los Campos, Gustavo; Al-Hamdan, Mohammad Z; Safford, Monika M; Levitan, Emily B; McClure, Leslie A

    2017-01-01

    Geographic variations in cardiovascular mortality are substantial, but descriptions of geographic variations in major cardiovascular risk factors have relied on data aggregated to counties. Herein, we provide the first description of geographic variation in the prevalence of hypertension, diabetes mellitus, and smoking within and across US counties. We conducted a cross-sectional analysis of baseline risk factor measurements and latitude/longitude of participant residence collected from 2003 to 2007 in the REGARDS study (Reasons for Geographic and Racial Differences in Stroke). Of the 30 239 participants, all risk factor measurements and location data were available for 28 887 (96%). The mean (±SD) age of these participants was 64.8(±9.4) years; 41% were black; 55% were female; 59% were hypertensive; 22% were diabetic; and 15% were current smokers. In logistic regression models stratified by race, the median(range) predicted prevalence of the risk factors were as follows: for hypertension, 49% (45%-58%) among whites and 72% (68%-78%) among blacks; for diabetes mellitus, 14% (10%-20%) among whites and 31% (28%-41%) among blacks; and for current smoking, 12% (7%-16%) among whites and 18% (11%-22%) among blacks. Hypertension was most prevalent in the central Southeast among whites, but in the west Southeast among blacks. Diabetes mellitus was most prevalent in the west and central Southeast among whites but in south Florida among blacks. Current smoking was most prevalent in the west Southeast and Midwest among whites and in the north among blacks. Geographic disparities in prevalent hypertension, diabetes mellitus, and smoking exist within states and within counties in the continental United States, and the patterns differ by race. © 2017 American Heart Association, Inc.

  12. Heat and Humidity in the City: Neighborhood Heat Index Variability in a Mid-Sized City in the Southeastern United States.

    Science.gov (United States)

    Hass, Alisa L; Ellis, Kelsey N; Reyes Mason, Lisa; Hathaway, Jon M; Howe, David A

    2016-01-11

    Daily weather conditions for an entire city are usually represented by a single weather station, often located at a nearby airport. This resolution of atmospheric data fails to recognize the microscale climatic variability associated with land use decisions across and within urban neighborhoods. This study uses heat index, a measure of the combined effects of temperature and humidity, to assess the variability of heat exposure from ten weather stations across four urban neighborhoods and two control locations (downtown and in a nearby nature center) in Knoxville, Tennessee, USA. Results suggest that trees may negate a portion of excess urban heat, but are also associated with greater humidity. As a result, the heat index of locations with more trees is significantly higher than downtown and areas with fewer trees. Trees may also reduce heat stress by shading individuals from incoming radiation, though this is not considered in this study. Greater amounts of impervious surfaces correspond with reduced evapotranspiration and greater runoff, in terms of overall mass balance, leading to a higher temperature, but lower relative humidity. Heat index and relative humidity were found to significantly vary between locations with different tree cover and neighborhood characteristics for the full study time period as well as for the top 10% of heat index days. This work demonstrates the need for high-resolution climate data and the use of additional measures beyond temperature to understand urban neighborhood exposure to extreme heat, and expresses the importance of considering vulnerability differences among residents when analyzing neighborhood-scale impacts.

  13. Heat pipes and heat pipe exchangers for heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, L L; Grakovich, L P; Kiselev, V G; Kurustalev, D K; Matveev, Yu

    1984-01-01

    Heat pipes and heat pipe exchangers are of great importance in power engineering as a means of recovering waste heat of industrial enterprises, solar energy, geothermal waters and deep soil. Heat pipes are highly effective heat transfer units for transferring thermal energy over large distance (tens of meters) with low temperature drops. Their heat transfer characteristics and reliable working for more than 10-15 yr permit the design of new systems with higher heat engineering parameters.

  14. ‘That’s when we started using the living room’ : lessons from a local history of domestic heating in the United Kingdom

    NARCIS (Netherlands)

    Kuijer, L.; Watson, M.

    Indoor climate control forms a major share of residential energy demand. Policy measures to curb this demand tend to focus on energy-efficient technologies. However, while the energy efficiency of domestic heat provision in the United Kingdom (UK) has increased considerably over the past century,

  15. Mathematical modelling and optimization of a large-scale combined cooling, heat, and power system that incorporates unit changeover and time-of-use electricity price

    International Nuclear Information System (INIS)

    Zhu, Qiannan; Luo, Xianglong; Zhang, Bingjian; Chen, Ying

    2017-01-01

    Highlights: • We propose a novel superstructure for the design and optimization of LSCCHP. • A multi-objective multi-period MINLP model is formulated. • The unit start-up cost and time-of-use electricity prices are involved. • Unit size discretization strategy is proposed to linearize the original MINLP model. • A case study is elaborated to demonstrate the effectiveness of the proposed method. - Abstract: Building energy systems, particularly large public ones, are major energy consumers and pollutant emission contributors. In this study, a superstructure of large-scale combined cooling, heat, and power system is constructed. The off-design unit, economic cost, and CO_2 emission models are also formulated. Moreover, a multi-objective mixed integer nonlinear programming model is formulated for the simultaneous system synthesis, technology selection, unit sizing, and operation optimization of large-scale combined cooling, heat, and power system. Time-of-use electricity price and unit changeover cost are incorporated into the problem model. The economic objective is to minimize the total annual cost, which comprises the operation and investment costs of large-scale combined cooling, heat, and power system. The environmental objective is to minimize the annual global CO_2 emission of large-scale combined cooling, heat, and power system. The augmented ε–constraint method is applied to achieve the Pareto frontier of the design configuration, thereby reflecting the set of solutions that represent optimal trade-offs between the economic and environmental objectives. Sensitivity analysis is conducted to reflect the impact of natural gas price on the combined cooling, heat, and power system. The synthesis and design of combined cooling, heat, and power system for an airport in China is studied to test the proposed synthesis and design methodology. The Pareto curve of multi-objective optimization shows that the total annual cost varies from 102.53 to 94.59 M

  16. Heat and Humidity in the City: Neighborhood Heat Index Variability in a Mid-Sized City in the Southeastern United States

    Directory of Open Access Journals (Sweden)

    Alisa L. Hass

    2016-01-01

    Full Text Available Daily weather conditions for an entire city are usually represented by a single weather station, often located at a nearby airport. This resolution of atmospheric data fails to recognize the microscale climatic variability associated with land use decisions across and within urban neighborhoods. This study uses heat index, a measure of the combined effects of temperature and humidity, to assess the variability of heat exposure from ten weather stations across four urban neighborhoods and two control locations (downtown and in a nearby nature center in Knoxville, Tennessee, USA. Results suggest that trees may negate a portion of excess urban heat, but are also associated with greater humidity. As a result, the heat index of locations with more trees is significantly higher than downtown and areas with fewer trees. Trees may also reduce heat stress by shading individuals from incoming radiation, though this is not considered in this study. Greater amounts of impervious surfaces correspond with reduced evapotranspiration and greater runoff, in terms of overall mass balance, leading to a higher temperature, but lower relative humidity. Heat index and relative humidity were found to significantly vary between locations with different tree cover and neighborhood characteristics for the full study time period as well as for the top 10% of heat index days. This work demonstrates the need for high-resolution climate data and the use of additional measures beyond temperature to understand urban neighborhood exposure to extreme heat, and expresses the importance of considering vulnerability differences among residents when analyzing neighborhood-scale impacts.

  17. Thermal analysis and modeling of a swimming pool heating system by utilizing waste energy rejected from a chiller unit of an ice rink

    Directory of Open Access Journals (Sweden)

    Kuyumcu Muhammed Enes

    2017-01-01

    Full Text Available This study deals with the thermal analysis and modeling of a swimming pool heating system in which the waste energy rejected from the chiller unit of an ice rink is used as an energy source. The system consists of a swimming pool and an ice rink coupled by a chiller unit. The swimming pool and the ice rink both indoor types and were constructed in city of Gaziantep, Turkey. The thermal energy requirement for each section is determined by thermal analysis of each component of the system. Effects of different design parameters such as ceiling insulation thickness, ceiling emissivity, Carnot efficiency factor and size of the ice rink on the thermal energy requirements and coefficient of performance of the chiller unit are investigated. As a result of analyses of the system, the minimum ice rink area is determined in order to meet annual total heat energy demand of the olympic-sized swimming pool.

  18. Flow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units

    DEFF Research Database (Denmark)

    Zhang, Ji; Desideri, Adriano; Kærn, Martin Ryhl

    2017-01-01

    . This paper is aimed at obtaining flow boiling heat transfer and pressure drop characteristics in a plate heat exchanger under the working conditions prevailing in the evaporator of organic Rankine cycle units. Two hydrofluoroolefins R1234yf and R1234ze, and one hydrofluorocarbon R134a, were selected...... as the working fluids. The heat transfer coefficients and pressure drops of the three working fluids were measured with varying saturation temperatures, mass fluxes, heat fluxes and outlet vapour qualities, which range from 60°C to 80°C, 86 kg/m2 s to 137 kg/m2 s, 9.8 kW/m2 to 36.8 kW/m2 and 0.5 to 1...... developed that are more suitable for evaporation in organic Rankine cycles. The experimental results indicate that heat transfer coefficients are strongly dependent upon the heat flux and saturation temperature. Moreover, the results suggest better thermal-hydraulic performance for R1234yf than the other...

  19. Field tests for the comparative evaluation of heat and enthalpy exchangers in compact ventilation units; Feldvergleich von Waerme- und Enthalpieuebertragern in Kompakt-Lueftungsgeraeten - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Frei, B.

    2007-07-01

    In an efficiency review on low energy buildings promoted by the Swiss Federal Office of Energy, low air humidity has been measured during thousands of annual hours. Modern compact ventilation units are being increasingly offered with transmission of heat and moisture. One possibility to raise the air humidity level is an enthalpy exchanger with steam-permeable membranes. With an enthalpy exchanger you can not only recover heat but also a good part of the humidity of the return air. In a comparative field study alternate applications with enthalpy or heat exchangers have been analysed at four different locations. Also calculations have been made to estimate how a rotating heat exchanger with ion-exchange resin would have performed. The comparative field study has shown that the enthalpy exchanger is able to raise the humidity level. Conditions for this are internal humidity loads, balanced air volume rates which correspond to occupancy as well as low leakages of the ventilation unit. Over-moistening due to the system with enthalpy exchanger was not found. The measurements have been affected by a sequence of winter months which have been partially warmer than usual. Otherwise the difference between enthalpy and heat exchangers would have been more significant. (author)

  20. The local response of elastic tubes and shells to spherical pressure pulse loading

    International Nuclear Information System (INIS)

    Thompson, J.J.; Holy, Z.J.

    1977-01-01

    This paper develops a formulation and numerical solution technique for calculating the peak transient stresses developed in tubes or shells with external and internal acoustic media, as a result of shock loadings which may be represented as originating from external or internal point symmetric or dipole sources. The field of application is intended to be the local peak response of the cylindrical fuel cans, core barrels, pressure vessels, pipes and containment shells of Nuclear Reactor Technology, subjected to transient pressure shock loadings for a variety of operational or accident conditions, which cannot adequately be described as one dimensional plane shocks, for which elastic shell responses have been presented by other workers. The work reported here concerns the basic problem of an infinite static fluid filled hollow cylinder of arbitrary thickness, in an infinite static fluid medium, with a source at an arbitrary internal or external radial location. An acoustic model is used, with acoustic damping due to radiation as the only possible damping mechanism. The formulation and solution technique is based on the availability of the multi-dimensional Fast Fourier Transform algorithm. The basic result is the representation, in cylindrical co-ordinates, of the two dimensional (time and axial co-ordinate) Fourier Transform of the infinite medium frequency response function for outgoing waves from a point symmetrical source, as a series of azimuthal Fourier harmonics, from which the result for a dipole source of arbitrary orientation follows. Where possible numerical results will be presented

  1. Optimization of shell-and-tube heat exchangers conforming to TEMA standards with designs motivated by constructal theory

    International Nuclear Information System (INIS)

    Yang, Jie; Fan, Aiwu; Liu, Wei; Jacobi, Anthony M.

    2014-01-01

    Highlights: • A design method of heat exchangers motivated by constructal theory is proposed. • A genetic algorithm is applied and the TEMA standards are rigorously followed. • Three cases are studied to illustrate the advantage of the proposed design method. • The design method will reduce the total cost compared to two other methods. - Abstract: A modified optimization design approach motivated by constructal theory is proposed for shell-and-tube heat exchangers in the present paper. In this method, a shell-and-tube heat exchanger is divided into several in-series heat exchangers. The Tubular Exchanger Manufacturers Association (TEMA) standards are rigorously followed for all design parameters. The total cost of the whole shell-and-tube heat exchanger is set as the objective function, including the investment cost for initial manufacture and the operational cost involving the power consumption to overcome the frictional pressure loss. A genetic algorithm is applied to minimize the cost function by adjusting parameters such as the tube and shell diameters, tube length and tube arrangement. Three cases are studied which indicate that the modified design approach can significantly reduce the total cost compared to the original design method and traditional genetic algorithm design method

  2. Validation of intermediate heat and decay heat exchanger model in MARS-LMR with STELLA-1 and JOYO tests

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Ha, Kwiseok; Hong, Jonggan; Yeom, Sujin; Eoh, Jaehyuk [Sodium-cooled Fast Reactor Design Division, Korea Atomic Energy Research Institute (KAERI), 989-111, Daedeok-Daero, Yuseong-Gu, Daejeon 305-353 (Korea, Republic of); Jeong, Hae-yong, E-mail: hyjeong@sejong.ac.kr [Department of Nuclear Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

    2016-11-15

    , respectively. It was reported that a bypass flow of 20% was allowed in type A test. When the bypass flow model was added to MARS-LMR, the RMS error for type A reduced to 12.6%. The RMS error for the STELLA-1 DHX was estimated to be 3.5%. Through the comparative studies with various alternative heat transfer models in the tube and shell-side, the base heat transfer model in MARS-LMR was found to give good prediction for the STELLA-1 and JOYO experiment results.

  3. Conceptual design of a FGM thermoelectric energy conversion system for high temperature heat source. 1. Design of thermoelectric energy conversion unit

    International Nuclear Information System (INIS)

    Kambe, Mitsuru; Teraki, Junichi; Hirano, Toru.

    1996-01-01

    Thermoelectric (TE) power conversion system has been focused as a candidate of direct energy conversion systems for high temperature heat source to meet the various power requirements in next century. A concept of energy conversion unit by using TE cell elements combined with FGM compliant pads has been presented to achieve high thermal energy density as well as high energy conversion efficiency. An energy conversion unit consists of 8 couples of P-N cell elements sandwiched between two FGM compliant pads. Performance analysis revealed that the power generated by this unit was 11 watts which is nearly ten times as much as conventional unit of the same size. Energy conversion efficiency of 12% was expected based on the assumption of ZT = 1. All the member of compliant pads as well as TE cells could be bonded together to avoid thermal resistance. (author)

  4. Performance of a reversible heat pump/organic Rankine cycle unit coupled with a passive house to get a positive energy building

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Fontaine, Valentin

    2016-01-01

    This paper presents an innovative technology that can be used to deliver more renewable electricity production than the total electrical consumption of a building while covering the heat demand on a yearly basis. The technology concept uses a heat pump (HP), slightly modified to revert its cycle...... and generate electricity, coupled to a solar thermal collector roof. This reversible HP/organic Rankine cycle unit presents three operating modes: direct heating, HP and organic Rankine cycle. This work focuses on describing the dynamic model of the multi-component system followed by a techno-economic analysis......Wh/year and total electrical consumption of 2318 kWh/year) with a 138.8 m2 solar roof in Denmark....

  5. STEAM GENERATOR TUBE INTEGRITY ANALYSIS OF A TOTAL LOSS OF ALL HEAT SINKS ACCIDENT FOR WOLSONG NPP UNIT 1

    Directory of Open Access Journals (Sweden)

    HEOK-SOON LIM

    2014-02-01

    Full Text Available A total loss of all heat sinks is considered a severe accident with a low probability of occurrence. Following a total loss of all heat sinks, the degasser/condenser relief valves (DCRV become the sole means available for the depressurization of the primary heat transport system. If a nuclear power plant has a total loss of heat sinks accident, high-temperature steam and differential pressure between the primary heat transport system (PHTS and the steam generator (SG secondary side can cause a SG tube creep rupture. To protect the PHTS during a total loss of all heat sinks accident, a sufficient depressurization capability of the degasser/condenser relief valve and the SG tube integrity is very important. Therefore, an accurate estimation of the discharge through these valves is necessary to assess the impact of the PHTS overprotection and the SG tube integrity of the primary circuit. This paper describes the analysis of DCRV discharge capacity and the SG tube integrity under a total loss of all heat sink using the CATHENA code. It was found that the DCRV's discharge capacity is enough to protect the overpressure in the PHTS, and the SG tube integrity is maintained in a total loss of all heat accident.

  6. Steam Generator Tube Integrity Analysis of A Total Loss of all Heat Sinks Accident for Wolsong NPP Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Heoksoon; Song, Taeyoung; Chi, Moongoo [Korea Htydro and Nuclear Power Co., Ltd., Daejeon (Korea, Republic of); Kim, Seoungrae [Nuclear Engineering Service and Solution, Daejeon (Korea, Republic of)

    2014-02-15

    A total loss of all heat sinks is considered a severe accident with a low probability of occurrence. Following a total loss of all heat sinks, the degasser/condenser relief valves (DCRV) become the sole means available for the depressurization of the primary heat transport system. If a nuclear power plant has a total loss of heat sinks accident, high-temperature steam and differential pressure between the primary heat transport system (PHTS) and the steam generator (SG) secondary side can cause a SG tube creep rupture. To protect the PHTS during a total loss of all heat sinks accident, a sufficient depressurization capability of the degasser/condenser relief valve and the SG tube integrity is very important. Therefore, an accurate estimation of the discharge through these valves is necessary to assess the impact of the PHTS overprotection and the SG tube integrity of the primary circuit. This paper describes the analysis of DCRV discharge capacity and the SG tube integrity under a total loss of all heat sink using the CATHENA code. It was found that the DCRV's discharge capacity is enough to protect the overpressure in the PHTS, and the SG tube integrity is maintained in a total loss of all heat accident.

  7. Steam Generator Tube Integrity Analysis of A Total Loss of all Heat Sinks Accident for Wolsong NPP Unit 1

    International Nuclear Information System (INIS)

    Lim, Heoksoon; Song, Taeyoung; Chi, Moongoo; Kim, Seoungrae

    2014-01-01

    A total loss of all heat sinks is considered a severe accident with a low probability of occurrence. Following a total loss of all heat sinks, the degasser/condenser relief valves (DCRV) become the sole means available for the depressurization of the primary heat transport system. If a nuclear power plant has a total loss of heat sinks accident, high-temperature steam and differential pressure between the primary heat transport system (PHTS) and the steam generator (SG) secondary side can cause a SG tube creep rupture. To protect the PHTS during a total loss of all heat sinks accident, a sufficient depressurization capability of the degasser/condenser relief valve and the SG tube integrity is very important. Therefore, an accurate estimation of the discharge through these valves is necessary to assess the impact of the PHTS overprotection and the SG tube integrity of the primary circuit. This paper describes the analysis of DCRV discharge capacity and the SG tube integrity under a total loss of all heat sink using the CATHENA code. It was found that the DCRV's discharge capacity is enough to protect the overpressure in the PHTS, and the SG tube integrity is maintained in a total loss of all heat accident

  8. Heat and Mass Transfer during Hydrogen Generation in an Array of Fuel Bars of a BWR Using a Periodic Unit Cell

    Directory of Open Access Journals (Sweden)

    H. Romero-Paredes

    2012-01-01

    Full Text Available This paper presents, the numerical analysis of heat and mass transfer during hydrogen generation in an array of fuel cylinder bars, each coated with a cladding and a steam current flowing outside the cylinders. The analysis considers the fuel element without mitigation effects. The system consists of a representative periodic unit cell where the initial and boundary-value problems for heat and mass transfer were solved. In this unit cell, we considered that a fuel element is coated by a cladding with steam surrounding it as a coolant. The numerical simulations allow describing the evolution of the temperature and concentration profiles inside the nuclear reactor and could be used as a basis for hybrid upscaling simulations.

  9. Thermal analysis and modeling of a swimming pool heating system by utilizing waste energy rejected from a chiller unit of an ice rink

    OpenAIRE

    Kuyumcu Muhammed Enes; Yumrutaş Recep

    2017-01-01

    This study deals with the thermal analysis and modeling of a swimming pool heating system in which the waste energy rejected from the chiller unit of an ice rink is used as an energy source. The system consists of a swimming pool and an ice rink coupled by a chiller unit. The swimming pool and the ice rink both indoor types and were constructed in city of Gaziantep, Turkey. The thermal energy requirement for each section is determined by thermal analysis of each component of the system. Effec...

  10. Probabilistic assessment of the potential indoor air impacts of vent-free gas heating appliances in energy-efficient homes in the United States.

    Science.gov (United States)

    Whitmyre, Gary K; Pandian, Muhilan D

    2018-06-01

    Use of vent-free gas heating appliances for supplemental heating in U.S. homes is increasing. However, there is currently a lack of information on the potential impact of these appliances on indoor air quality for homes constructed according to energy-efficient and green building standards. A probabilistic analysis was conducted to estimate the impact of vent-free gas heating appliances on indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO 2 ), carbon dioxide (CO 2 ), water vapor, and oxygen in "tight" energy-efficient homes in the United States. A total of 20,000 simulations were conducted for each Department of Energy (DOE) heating region to capture a wide range of home sizes, appliance features, and conditions, by varying a number of parameters, e.g., room volume, house volume, outdoor humidity, air exchange rates, appliance input rates (Btu/hr), and house heat loss factors. Predicted airborne levels of CO were below the U.S. Environmental Protection Agency (EPA) standard of 9 ppm for all modeled cases. The airborne concentrations of NO 2 were below the U.S. Consumer Product Safety Commission (CPSC) guideline of 0.3 ppm and the Health Canada benchmark of 0.25 ppm in all cases and were below the World Health Organization (WHO) standard of 0.11 ppm in 99-100% of all cases. Predicted levels of CO 2 were below the Health Canada standard of 3500 ppm for all simulated cases. Oxygen levels in the room of vent-free heating appliance use were not significantly reduced. The great majority of cases in all DOE regions were associated with relative humidity (RH) levels from all indoor water vapor sources that were less than the EPA-recommended 70% RH maximum to avoid active mold and mildew growth. The conclusion of this investigation is that when installed in accordance with the manufacturer's instructions, vent-free gas heating appliances maintain acceptable indoor air quality in tight energy-efficient homes, as defined by the standards referenced in

  11. Heat unit accumulation and inflorescence and fruit development in ‘Ubá’ mango trees grown in Visconde do Rio Branco-MG

    Directory of Open Access Journals (Sweden)

    Lorena Moreira Carvalho Lemos

    2018-04-01

    Full Text Available Abstract There are little information in the scientific literature on flowering and fruiting of ‘Ubá’ mango trees. These information enables to know the proportion of hermaphrodite flowers in inflorescence, fruit set percentage and developmental stages of the fruit. In this study evaluations on inflorescence and fruit development of the ‘Ubá’ mango tree (Mangifera indica L. were carried out, as well as the determination of the required number of heat units for full fruit development. Thirty branches whose terminal buds were swollen were selected from five mango trees. With the aid of a camera and a caliper, the panicle and fruit development were evaluated weekly until full fruit development. A digital thermometer was used to record ambient temperatures during fruit development in order to estimate the number of heat units required for complete development of the fruits. Male and hermaphrodite flowers of the panicles were also identified and counted. The developmental cycle of ‘Ubá’ mango from the beginning of apical bud swelling to commercial harvest of the fruit lasted 168 days in 2011 and 154 days in 2012. The number of hermaphrodite flowers and the percentage of fruit set in the inflorescence in 2011 were 32.3 and 0.066%, respectively; and 122.1 and 0.099% in 2012, respectively. There was accumulation of 3,173 heat units from flower bud swelling to full development of the ‘Ubá’ mangoes.

  12. Split heat pipe heat recovery system

    OpenAIRE

    E. Azad

    2008-01-01

    This paper describes a theoretical analysis of a split heat pipe heat recovery system. The analysis is based on an Effectiveness-NTU approach to deduce its heat transfer characteristics. In this study the variation of overall effectiveness of heat recovery with the number of transfer units are presented. Copyright , Manchester University Press.

  13. Assessment of the Long Term Trends in Extreme Heat Events and the Associated Health Impacts in the United States

    Science.gov (United States)

    Bell, J.; Rennie, J.; Kunkel, K.; Herring, S.; Cullen, H. M.

    2017-12-01

    Land surface air temperature products have been essential for monitoring the evolution of the climate system. Before a temperature dataset is included in such reports, it is important that non-climatic influences be removed or changed so the dataset is considered homogenous. These inhomogeneities include changes in station location, instrumentation and observing practices. While many homogenized products exist on the monthly time scale, few daily products exist, due to the complication of removing breakpoints that are truly inhomogeneous rather than solely by chance (for example, sharp changes due to synoptic conditions). Recently, a sub monthly homogenized dataset has been developed using data and software provided by NOAA's National Centers for Environmental Information (NCEI). Homogeneous daily data are useful for identification and attribution of extreme heat events over a period of time. Projections of increasing temperatures are expected to result in corresponding increases in the frequency, duration, and intensity of extreme heat events. It is also established that extreme heat events can have significant public health impacts, including short-term increases in mortality and morbidity. In addition, it can exacerbate chronic health conditions in vulnerable populations, including renal and cardiovascular issues. To understand how heat events impact a specific population, it will be important to connect observations on the duration and intensity of extreme heat events with health impacts data including insurance claims and hospital admissions data. This presentation will explain the methodology to identify extreme heat events, provide a climatology of heat event onset, length and severity, and explore a case study of an anomalous heat event with available health data.

  14. An assessment of the present and future opportunities for combined heat and power with district heating (CHP-DH) in the United Kingdom

    International Nuclear Information System (INIS)

    Kelly, Scott; Pollitt, Michael

    2010-01-01

    As global fuel reserves are depleted, alternative and more efficient forms of energy generation and delivery will be required. Combined heat and power with district heating (CHP-DH) provides an alternative energy production and delivery mechanism that is less resource intensive, more efficient and provides greater energy security than many popular alternatives. It will be shown that the economic viability of CHP-DH networks depends on several principles, namely (1) the optimisation of engineering and design principles; (2) organisational and regulatory frameworks; (3) financial and economic factors. It was found that in the long term DH is competitive with other energy supply and distribution technologies such as electricity and gas. However, in the short to medium term it is shown that economic risk, regulatory uncertainty and lock-in of existing technology are the most significant barriers to CHP-DH development. This research suggests that under the present regulatory and economic paradigm, the infrastructure required for DH networks remains financially prohibitive; the implementation of government policies are complicated and impose high transaction costs, while engineering solutions are frequently not implemented or economically optimised. If CHP-DH is going to play any part in meeting climate change targets then collaboration between public and private organisations will be required. It is clear from this analysis that strong local government involvement is therefore necessary for the co-ordination, leadership and infrastructural deployment of CHP-DH.

  15. Layout of heating units for solar-heated gas turbine systems with paraboloid collectors. Die Auslegung von Erhitzern Solar beheizter Gasturbinenanlagen mit Paraboloidkollektoren

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, P

    1983-07-04

    Solar energy is converted in a gas turbine plant, with solar radiation collected in a parabolic collector and reflected into a hollow receiver. The receiver, which is rigidly connected to the collector, consists of a conical bottom part and a cylindrical upper part. The highly focussed radiation enters through the aperture of the conus. The cool, compressed working fluid of the gas turbine flows through pipes arranged in front of the cylindrical inner wall. The distribution of the radiation was studied as well as the resulting receiver wall temperature, radiation losses and useful heat absorbed by the working fluid. Temperature distributions and three-dimensional fields of thermal stresses were calculated. The influence of geometric and thermodynamic parameters on the stresses inside the pipes was studied in consideration of thermal stresses and stresses due to working fluid pressure. The findings will help to optimize the heating surface load, material utilisation, and efficiency of the receiver. The interdependences between receiver characteristics and gas turbine operation are explained.

  16. Numerical Study of the Dynamic Response of Heat and Mass Transfer to Operation Mode Switching of a Unitized Regenerative Fuel Cell

    Directory of Open Access Journals (Sweden)

    Hong Xiao

    2016-12-01

    Full Text Available Knowledge concerning the complicated changes of mass and heat transfer is desired to improve the performance and durability of unitized regenerative fuel cells (URFCs. In this study, a transient, non-isothermal, single-phase, and multi-physics mathematical model for a URFC based on the proton exchange membrane is generated to investigate transient responses in the process of operation mode switching from fuel cell (FC to electrolysis cell (EC. Various heat generation mechanisms, including Joule heat, reaction heat, and the heat attributed to activation polarizations, have been considered in the transient model coupled with electrochemical reaction and mass transfer in porous electrodes. The polarization curves of the steady-state models are validated by experimental data in the literatures. Numerical results reveal that current density, gas mass fractions, and temperature suddenly change with the sudden change of operating voltage in the mode switching process. The response time of temperature is longer than that of current density and gas mass fractions. In both FC and EC modes, the cell temperature and gradient of gas mass fraction in the oxygen side are larger than that in the hydrogen side. The temperature difference of the entire cell is less than 1.5 K. The highest temperature appears at oxygen-side catalyst layer under the FC mode and at membrane under a more stable EC mode. The cell is exothermic all the time. These dynamic responses and phenomena have important implications for heat analysis and provide proven guidelines for the improvement of URFCs mode switching.

  17. CO{sub 2} reduction: potential of heat pumps when used together with combined heat and power units; Potentiel energetique des pompes a chaleur combinees au couplage chaleur-force. Pour une reduction maximale des emissions de CO{sub 2} et pour une production de courant fossile avec reduction des emissions de CO{sub 2} en Suisse - Rapport final

    Energy Technology Data Exchange (ETDEWEB)

    Rognon, F.

    2005-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project that examined the potential of using heat pumps in combination with Combined Heat and Power (CHP) units as a replacement for fossil-fuel fired heating units in Switzerland. The electrical power produced by the CHP units can be used to provide power for the drives of heat pump systems. The author states that the fossil fuel consumption and the resulting emissions of carbon dioxide can be halved using this combination. Also, even more efficient systems using power produced in larger combined-cycle power generation are discussed. Further examples of how fossil-fired power generation in combination with heat pumps can not only replace fossil-fuelled heating systems but also provide additional electricity too are given. This overview includes figures on the potential of such combined systems.

  18. Steady natural convection heat transfer experiments in a horizontal annulus for the United States Spent Fuel Shipping Cask Technology Program

    International Nuclear Information System (INIS)

    Boyd, R.D.

    1981-04-01

    This experimental study deals with the measurement of the heat transfer across a horizontal annulus which is formed by an inner hexagonal cylinder and an outer concentric circular cylinder. The geometry simulates, in two dimensions, a liquid metal fast breeder reactor radioactive fuel subassembly inside a shipping container. This geometry is also similar to a radioactive fuel pin inside a horizontal reactor subassembly. The objective of the experiments is to measure the local and mean heat transfer at the surface of the inner hexagonal cylinder

  19. European ErP Directive. Total condensing technology: the solution for heating and DHW units in the hotel sector

    International Nuclear Information System (INIS)

    Martín, G.

    2016-01-01

    Since 26 September 2015, the Ecodesign ErP Directive has been of compulsory application for EU Member States as regards the design of Energy-related Products (ErP) and as from its entry into force only those products manufactured according to the ErP requirements can be sold with the EC label. Although this directive affects over 1,000 product categories, for those relating to HVAC and DHW production, it covers boilers, heat pumps, accumulators, cogeneration systems, combined products systems, establishing their minimum efficiency levels, the maximum levels of NOX emissions, the minimum insulation for accumulators and the maximum level of acoustic emissions for heat pumps. (Author)

  20. Assessment of Coping Capability of KORI Unit 1 under Extended Loss AC Power and Loss of Ultimate Heat Sink Initiated by Beyond Design Natural Disaster

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Hyun; Ha, Sang Jun [KHNP CRI, Daejeon (Korea, Republic of); Han, Kee Soo [Nuclear Engineering Service and Solution (NESS) Co. Ltd., Deajeon (Korea, Republic of); Park, Chan Eok [KEPCO Engineering and Constructd., Deajeon (Korea, Republic of)

    2016-10-15

    In Korea, the government and industry performed comprehensive safety inspection on all domestic nuclear power plants against beyond design basis external events and fifty action items have been issued. In addition to post- Fukushima action items, the stress tests for all domestic nuclear power plants are on the way to enhance the safety of domestic nuclear power plants through finding the vulnerabilities in intentional stress conditions initiated by beyond design natural disaster. This paper presents assessment results of coping capability of KORI Unit 1 under the simultaneous Extended Loss of AC Power (ELAP) and Loss of Ultimate Heat Sink (LUHS) which is a representative plant condition initiated by beyond design natural disaster. The assessment of the coping capability of KORI Unit 1 has been performed under simultaneous the extended loss of AC power and loss of ultimate heat sink initiated by beyond design natural disaster. It is concluded that KORI Unit 1 has the capability, in the event of loss of safety functions by beyond design natural disaster, to sufficiently cool down the reactor core without fuel damage, to keep pressure boundaries of the reactor coolant system in transient condition and to control containment and temperature to maintain the integrity of the containment buildings.

  1. Assessment of Coping Capability of KORI Unit 1 under Extended Loss AC Power and Loss of Ultimate Heat Sink Initiated by Beyond Design Natural Disaster

    International Nuclear Information System (INIS)

    Kim, Chang Hyun; Ha, Sang Jun; Han, Kee Soo; Park, Chan Eok

    2016-01-01

    In Korea, the government and industry performed comprehensive safety inspection on all domestic nuclear power plants against beyond design basis external events and fifty action items have been issued. In addition to post- Fukushima action items, the stress tests for all domestic nuclear power plants are on the way to enhance the safety of domestic nuclear power plants through finding the vulnerabilities in intentional stress conditions initiated by beyond design natural disaster. This paper presents assessment results of coping capability of KORI Unit 1 under the simultaneous Extended Loss of AC Power (ELAP) and Loss of Ultimate Heat Sink (LUHS) which is a representative plant condition initiated by beyond design natural disaster. The assessment of the coping capability of KORI Unit 1 has been performed under simultaneous the extended loss of AC power and loss of ultimate heat sink initiated by beyond design natural disaster. It is concluded that KORI Unit 1 has the capability, in the event of loss of safety functions by beyond design natural disaster, to sufficiently cool down the reactor core without fuel damage, to keep pressure boundaries of the reactor coolant system in transient condition and to control containment and temperature to maintain the integrity of the containment buildings

  2. Energy Savings and Economics of Advanced Control Strategies for Packaged Air-Conditioning Units with Gas Heat

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weimin; Katipamula, Srinivas; Huang, Yunzhi; Brambley, Michael R.

    2011-12-31

    Pacific Northwest National Laboratory (PNNL) with funding from the U.S. Department of Energy's Building Technologies Program (BTP) evaluated a number of control strategies that can be implemented in a controller, to improve the operational efficiency of the packaged air conditioning units. The two primary objectives of this research project are: (1) determine the magnitude of energy savings achievable by retrofitting existing packaged air conditioning units with advanced control strategies not ordinarily used for packaged units and (2) estimating what the installed cost of a replacement control with the desired features should be in various regions of the U.S. This document reports results of the study.

  3. Results of Steam-Water-Oxygen Treatment of the Inside of Heating Surfaces in Heat-Recovery Steam Generators of the PGU-800 Power Unit at the Perm' District Thermal Power Station

    Science.gov (United States)

    Ovechkina, O. V.; Zhuravlev, L. S.; Drozdov, A. A.; Solomeina, S. V.

    2018-05-01

    Prestarting, postinstallation steam-water-oxygen treatment (SWOT) of the natural circulation/steam reheat heat-recovery steam generators (HRSG) manufactured by OAO Krasny Kotelshchik was performed at the PGU-800 power unit of the Perm District Thermal Power Station (GRES). Prior to SWOT, steam-oxygen cleaning, passivation, and preservation of gas condensate heaters (GCH) of HRSGs were performed for 10 h using 1.3MPa/260°C/70 t/h external steam. After that, test specimens were cut out that demonstrated high strength of the passivating film. SWOT of the inside of the heating surfaces was carried out during no-load operation of the gas turbine unit with an exhaust temperature of 280-300°C at the HRSG inlet. The steam turbine was shutdown, and the generated steam was discharged into the atmosphere. Oxygen was metered into the discharge pipeline of the electricity-driven feed pumps and downcomers of the evaporators. The behavior of the concentration by weight of iron compounds and the results of investigation of cutout specimens by the drop or potentiometric method indicate that the steam-water-oxygen process makes it possible to remove corrosion products and reduce the time required to put a boiler into operation. Unlike other processes, SWOT does not require metal-intensive cleaning systems, temporary metering stations, and structures for collection of the waste solution.

  4. Biogas combined-heat-and-power-unit in practice: emission behaviour and performance behaviour; Biogas-BHKW in der Praxis: Emissions- und Leistungsverhalten

    Energy Technology Data Exchange (ETDEWEB)

    Aschmann, V.; Kissel, R.; Gronauer, A. [Bayerische Landesanstalt fuer Landwirtschaft (LfL), Freising-Weihenstephan (Germany). Inst. fuer Landtechnik und Tierhaltung

    2007-07-01

    The electrical power output of the combined-heat-and-power-unit (CHPU) is prioritized when biogas is used for electricity production. However, during servicing and adjusting of engines, beside power output, exhaust gas emissions should also be taken into consideration. Investigations at several biogas driven CHPU prior to maintenance revealed NO{sub x}-levels in the exhaust gas that were in part considerably in excess of respective limit values. The limit values could be met by servicing and adjusting the engine, but this resulted in decreased electrical efficiency and power output. (orig.)

  5. A new tool of decentralized power supply. Micro-cogeneration unit for heat and power supply; Neuer Spielball der dezentralen Energieversorgung. Mikro-Waermekraftkopplung liefert Strom und Waerme

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-07-01

    Small fuel cell heating systems have renewed interest in decentralized power supply. The Dutch company EnAtEc recently announced their intention of presenting a micro-cogeneration unit ({mu}WK) at this year's ISH. The unit is a combination of a gas-fuelled high-efficiency boiler and a free-piston Stirling engine. With 1 kW{sub el} and 6 - 24 kW{sub th} it is suited for single-family dwellings. [German] Kleine Brennstoffzellenheizgeraete haben eine rege Diskussion um die dezentrale Energieversorgung entfacht. Juengst ueberraschte die niederlaendische Firma EnAtEc mit der Ankuendigung, zur ISH eine ''Mikro-Waermekraftkopplung'' ({mu}WK) vorzustellen. Das Geraet kombiniert einen Gas-Brennwertkessel mit einer Freikolben-Stirlingmaschine. Mit Leistungen von 1 kW{sub el} und 6 bis 24 kW{sub th} zielt die {mu}WK auf Einfamilienhaushalte. (orig.)

  6. NUMERICAL MODELING OF CONJUGATE HEAT TRANSFER IN AN INSULATED GLASS UNIT (IGU WITH ACCOUNT FOR ITS DEFORMATION

    Directory of Open Access Journals (Sweden)

    Golubev Stanislav Sergeevich

    2012-12-01

    The effects of different climatic impacts lead to the deformation of glasses within an IGU (and its vertical cavity, respectively. Deformation of glasses and vertical cavities reduces the thermal resistance of an IGU. A numerical simulation of conjugate heat transfer within an IGU was implemented as part of the research into this phenomenon. Calculations were performed in ANSYS FLUENT CFD package. Basic equations describing the conservation of mass, conservation of momentum (in the Boussinesq approximation, conservation of energy were solved. Also, the radiation of the cavity wall was taken into account. Vertical walls were considered as non-isothermal, while horizontal walls were adiabatic. Calculations were made for several patterns of glass deformations. Calculation results demonstrate that the heat flow over vertical walls intensifies as the distance between centres of IGU glasses is reduced. The temperature in the central area of the hot glass drops.

  7. Solar unit

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, A M; Trushevskiy, S N; Tveryanovich, E V

    1982-01-01

    A solar unit is proposed which contains an inclined solar collector with supply and outlet pipelines, the first of which is connected to the source of a heat carrier, while the second is connected through the valve to the tank for collecting heated heat carrier equipped with a device for recovery. In order to improve the effectiveness of heating the heat carrier, it additionally contains a concentrator of solar radiation and a device for maintaining a level of the heat carrier in the collector in the zone of the focal spot of the concentrator, while the heat pipeline is connected to the source of the heat carrier with the help of a device for maintaining the level of the heat carrier.

  8. Heat Stroke

    DEFF Research Database (Denmark)

    Mørch, Sofie Søndergaard; Andersen, Johnny Dohn Holmgren; Bestle, Morten Heiberg

    2017-01-01

    not diagnosed until several days after admittance; hence treatment with cooling was delayed. Both patients were admitted to the intensive care unit, where they were treated with an external cooling device and received treatment for complications. Both cases ended fatally. As global warming continues, more heat......Heat stroke is an acute, life-threatening emergency characterized clinically by elevated body temperature and central nervous system dysfunction. Early recognition and treatment including aggressive cooling and management of life-threatening systemic complications are essential to reduce morbidity...... and mortality. This case report describes two Danish patients diagnosed with heat stroke syndrome during a heat wave in the summer of 2014. Both patients were morbidly obese and had several predisposing illnesses. However since heat stroke is a rare condition in areas with temperate climate, they were...

  9. A dynamic regrouping based sequential dynamic programming algorithm for unit commitment of combined heat and power systems

    DEFF Research Database (Denmark)

    Rong, Aiying; Hakonen, Henri; Lahdelma, Risto

    2009-01-01

    efficiency of the plants. We introduce in this paper the DRDP-RSC algorithm, which is a dynamic regrouping based dynamic programming (DP) algorithm based on linear relaxation of the ON/OFF states of the units, sequential commitment of units in small groups. Relaxed states of the plants are used to reduce...... the dimension of the UC problem and dynamic regrouping is used to improve the solution quality. Numerical results based on real-life data sets show that this algorithm is efficient and optimal or near-optimal solutions with very small optimality gap are obtained....

  10. An improvement of the base bleed unit on base drag reduction and heat energy addition as well as mass addition

    International Nuclear Information System (INIS)

    Xue, Xiaochun; Yu, Yonggang

    2016-01-01

    Highlights: • A 2D axisymmetric Navier-Stokes equation for a multi-component reactive system is solved. • The coupling of the internal and wake flow field with secondary combustion is calculated. • Detailed data with combined effects of boattailing and post-combustion are obtained. • The mechanism of heat energy addition and thermodynamics performances is investigated. - Abstract: Numerical simulations are carried out to investigate the base drag and energy characteristics of a base-bleed projectile with and without containing the effect of a post-combustion process for a boattailed afterbody in a supersonic flow, and then to analyze the key factor of drag reduction and pressure decreasing of base bleed projectile. Detailed chemistry models for H_2−CO combustion have been incorporated into a Navier-Stokes computer code and applied to flow field simulation in the base region of a base-bleed projectile. Detailed numerical results for the flow patterns and heat energy addition as well as mass addition for different conditions are presented and compared with existing experimental data. The results shows that, the post-combustion contributes to energy addition and base drag reduction up to 78% on account of that the heat energy released from the post-combustion using fuel-rich reaction products as the fuel in the wake region is much higher than for the corresponding cold bleed and hot bleed cases. In addition, the temperature distribution regularities are changed under post-combustion effect, presenting that the peak appears in a couple of recirculation regions. The fuel-rich bleed gas flows into the shear layer along the crack between these two recirculation regions and then those can readily burn when mixing with the freestream, thus causing component changes of H_2 and CO in the base flowfield.

  11. Monitoring Urban Heat Island Through Google Earth Engine: Potentialities and Difficulties in Different Cities of the United States

    Science.gov (United States)

    Ravanelli, R.; Nascetti, A.; Cirigliano, R. V.; Di Rico, C.; Monti, P.; Crespi, M.

    2018-04-01

    The aim of this work is to exploit the large-scale analysis capabilities of the innovative Google Earth Engine platform in order to investigate the temporal variations of the Urban Heat Island phenomenon as a whole. A intuitive methodology implementing a largescale correlation analysis between the Land Surface Temperature and Land Cover alterations was thus developed.The results obtained for the Phoenix MA are promising and show how the urbanization heavily affects the magnitude of the UHI effects with significant increases in LST. The proposed methodology is therefore able to efficiently monitor the UHI phenomenon.

  12. Thermodynamic and economic analysis of integrating lignocellulosic bioethanol production in a Danish combined heat and power unit

    DEFF Research Database (Denmark)

    Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik; Clausen, Lasse Røngaard

    bioethanol production in the Danish CHP unit Avedøreværket 1. Numerical models of the plants were developed, and feasible integration solutions were identified and optimised using exergy analysis. Hour-wise production simulations were run over a reference year, and market prices and economic parameters from...

  13. Direct Heat

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P J

    1990-01-01

    Potential resources and applications of earth heat in the form of geothermal energy are large. United States direct uses amount to 2,100 MWt thermal and worldwide 8,850 MWt above a reference temperature of 35 degrees Celsius. Space and district heating are the major direct uses of geothermal energy. Equipment employed in direct use projects is of standard manufacture and includes downhole and circulation pumps, transmission and distribution pipelines, heat exchangers and convectors, heat pumps and chillers. Direct uses of earth heat discussed are space and district heating, greenhouse heating and fish farming, process and industrial applications. The economic feasibility of direct use projects is governed by site specific factors such as location of user and resource, resource quality, system load factor and load density, as well as financing. Examples are presented of district heating in Klamath Falls, and Elko. Further developments of direct uses of geothermal energy will depend on matching user needs to the resource, and improving load factors and load density.

  14. A device for locating intercircuit leaks in heat transfer components of WWER steam generators during unit outage

    International Nuclear Information System (INIS)

    Matal, O.; Klinga, J.; Holy, F.; Fabian, S.

    1991-01-01

    The device is based on the following principle. The space between the tubes of the cold steam generator is filled with pressurized gas, the spaces of primary collectors in their bottom neck and in the attached tubing are waterproof-closed, and the inner spaces of the heat transfer tubes are gradually filled with modified water. This water is illuminated and its level is monitored. The formation and magnitude of flow and locality of source of gas bubbles leaking into the primary collector space are optically observed and acoustically measured. The device for this includes a module attached to a support, which is slidably located on a column. The module houses a water level indicator, a camera, a light source, and at least one acoustic sensor located under the water level. On the bottom part of the column, along which a water filling hose and a water tubing are led, is suspended an inflatable bag placed into the bottom neck of the primary collector and into the tubing. The water tubing empties in the lowest space, which is formed by the bottom neck of the primary collector and the surface of the inflated bag. On the inflatable bag is located a flange fitted with a light source oriented into the water-filled space of the primary collector, and with safety and attachment valves. (P.A.). 2 figs

  15. Spatially explicit estimation of heat stress-related impacts of climate change on the milk production of dairy cows in the United Kingdom

    Science.gov (United States)

    Topp, Cairistiona F. E.; Moorby, Jon M.; Pásztor, László; Foyer, Christine H.

    2018-01-01

    Dairy farming is one the most important sectors of United Kingdom (UK) agriculture. It faces major challenges due to climate change, which will have direct impacts on dairy cows as a result of heat stress. In the absence of adaptations, this could potentially lead to considerable milk loss. Using an 11-member climate projection ensemble, as well as an ensemble of 18 milk loss estimation methods, temporal changes in milk production of UK dairy cows were estimated for the 21st century at a 25 km resolution in a spatially-explicit way. While increases in UK temperatures are projected to lead to relatively low average annual milk losses, even for southern UK regions (cow), the ‘hottest’ 25×25 km grid cell in the hottest year in the 2090s, showed an annual milk loss exceeding 1300 kg/cow. This figure represents approximately 17% of the potential milk production of today’s average cow. Despite the potential considerable inter-annual variability of annual milk loss, as well as the large differences between the climate projections, the variety of calculation methods is likely to introduce even greater uncertainty into milk loss estimations. To address this issue, a novel, more biologically-appropriate mechanism of estimating milk loss is proposed that provides more realistic future projections. We conclude that South West England is the region most vulnerable to climate change economically, because it is characterised by a high dairy herd density and therefore potentially high heat stress-related milk loss. In the absence of mitigation measures, estimated heat stress-related annual income loss for this region by the end of this century may reach £13.4M in average years and £33.8M in extreme years. PMID:29738581

  16. Spatially explicit estimation of heat stress-related impacts of climate change on the milk production of dairy cows in the United Kingdom.

    Directory of Open Access Journals (Sweden)

    Nándor Fodor

    Full Text Available Dairy farming is one the most important sectors of United Kingdom (UK agriculture. It faces major challenges due to climate change, which will have direct impacts on dairy cows as a result of heat stress. In the absence of adaptations, this could potentially lead to considerable milk loss. Using an 11-member climate projection ensemble, as well as an ensemble of 18 milk loss estimation methods, temporal changes in milk production of UK dairy cows were estimated for the 21st century at a 25 km resolution in a spatially-explicit way. While increases in UK temperatures are projected to lead to relatively low average annual milk losses, even for southern UK regions (<180 kg/cow, the 'hottest' 25×25 km grid cell in the hottest year in the 2090s, showed an annual milk loss exceeding 1300 kg/cow. This figure represents approximately 17% of the potential milk production of today's average cow. Despite the potential considerable inter-annual variability of annual milk loss, as well as the large differences between the climate projections, the variety of calculation methods is likely to introduce even greater uncertainty into milk loss estimations. To address this issue, a novel, more biologically-appropriate mechanism of estimating milk loss is proposed that provides more realistic future projections. We conclude that South West England is the region most vulnerable to climate change economically, because it is characterised by a high dairy herd density and therefore potentially high heat stress-related milk loss. In the absence of mitigation measures, estimated heat stress-related annual income loss for this region by the end of this century may reach £13.4M in average years and £33.8M in extreme years.

  17. Use of an Esophageal Heat Exchanger to Maintain Core Temperature during Burn Excisions and to Attenuate Pyrexia on the Burns Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    David Williams

    2016-01-01

    Full Text Available Introduction. Burns patients are vulnerable to hyperthermia due to sepsis and SIRS and to hypothermia due to heat loss during excision surgery. Both states are associated with increased morbidity and mortality. We describe the first use of a novel esophageal heat exchange device in combination with a heater/cooler unit to manage perioperative hypothermia and postoperative pyrexia. Material and Methods. The device was used in three patients with full thickness burns of 51%, 49%, and 45% body surface area to reduce perioperative hypothermia during surgeries of >6 h duration and subsequently to control hyperthermia in one of the patients who developed pyrexia of 40°C on the 22nd postoperative day due to E. coli/Candida septicaemia which was unresponsive to conventional cooling strategies. Results. Perioperative core temperature was maintained at 37°C for all three patients, and it was possible to reduce ambient temperature to 26°C to increase comfort levels for the operating team. The core temperature of the pyrexial patient was reduced to 38.5°C within 2.5 h of instituting the device and maintained around this value thereafter. Conclusion. The device was easy to use with no adverse incidents and helped maintain normothermia in all cases.

  18. Financial analysis on the proposed renewable heat incentive for residential houses in the United Kingdom: A case study on the solar thermal system

    International Nuclear Information System (INIS)

    Abu-Bakar, Siti Hawa; Muhammad-Sukki, Firdaus; Ramirez-Iniguez, Roberto; Munir, Abu Bakar; Mohd Yasin, Siti Hajar; Mallick, Tapas Kumar; McLennan, Campbell; Abdul Rahim, Ruzairi

    2014-01-01

    This short communication paper focuses on the renewable heat incentive (RHI) scheme in the United Kingdom (UK); and in particular, on its implication on domestic installations of solar thermal systems (STSs). First, a short review on the STS in the UK is provided. Then, a detailed description of the RHI is discussed. A financial analysis is presented afterwards, analysing the impact of the RHI scheme on the applicants, in terms of the net present value and the internal rate of return. From the financial analysis it has been found that the RHI scheme for domestic installations is only attractive if a longer period of RHI payment, i.e. 17 years, or a higher RHI rate i.e. £0.32 per kW h is implemented. The current proposal from the UK government is not financially viable, and as a result, it may hinder the penetration of domestic solar thermal systems in the residential sector in the UK. - Highlights: • A short review on solar thermal system (STS) is presented. • The renewable heat incentive (RHI) scheme is discussed. • A financial analysis is evaluated under the RHI scheme in the UK. • The analysis indicates the current proposal is not desirable to consumers

  19. Heat and fluid flow in accident of Fukushima Daiichi Nuclear Power Plant, Unit 2. Accident scenario based on thermodynamic model

    International Nuclear Information System (INIS)

    Maruyama, Shigenao

    2012-01-01

    An accident scenario of Fukushima Daiichi Nuclear Power Plant, Unit 2 is analyzed from the data open to the public. Phase equilibrium process model was introduced that the vapor and water are at saturation point in the vessels. Proposed accident scenario agrees very well with the data of the plant parameters obtained just after the accident. The estimation describes that the rupture time of the reactor pressure vessel (RPV) was at 22:50 14/3/2011. The estimation shows that the rupture time of the pressure containment vessel (RCP) was at 7:40 15/3/2011. These estimations are different from the ones by TEPCO, however; many measured evidences show good accordance with the present scenario. (author)

  20. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Lund, Henrik

    2015-01-01

    This document is a summary of the key technical inputs for the modelling of the heat strategy for Europe outlined in the latest Heat Roadmap Europe studies [1, 2]. These studies quantify the impact of alternative heating strategies for Europe in 2030 and 2050. The study is based on geographical...... information systems (GIS) and energy system analyses. In this report, the inputs for other modelling tools such as PRIMES are presented, in order to enable other researches to generate similar heating scenarios for Europe. Although Heat Roadmap Europe presents a complete heat strategy for Europe, which...... includes energy efficiency, individual heating units (such as boilers and heat pumps), and heat networks, the recommendations here are primarily relating to the potential and modelling of district heating. Although other solutions will play a significant role in decarbonising the heating and cooling sector...

  1. The surface urban heat island response to urban expansion: A panel analysis for the conterminous United States

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaoma; Zhou, Yuyu; Asrar, Ghassem R.; Imhoff, Marc; Li, Xuecao

    2017-12-01

    Abstract: Urban heat island (UHI), a major concern worldwide, affects human health and energy use. With current and anticipated rapid urbanization, improved understanding of the response of UHI to urbanization is important for impact analysis and developing effective adaptation measures and mitigation strategies. Current studies mainly focus on a single or a few big cities and knowledge on the response of UHI to urbanization for large areas is very limited. Modelling UHI caused by urbanization for large areas that encompass multiple metropolitans remains a major scientific challenge/opportunity. As a major indicator of urbanization, urban area size lends itself well for representation in prognostic models to investigate the impacts of urbanization on UHI and the related socioeconomic and environmental effects. However, we have little knowledge on how UHI responds to the increase of urban area size, namely urban expansion, and its spatial and temporal variation over large areas. In this study, we investigated the relationship between surface UHI (SUHI) and urban area size in the climate and ecological context, and its spatial and temporal variations, based on a panel analysis of about 5000 urban areas of 10 km2 or larger, in the conterminous U.S. We found statistically significant positive relationship between SUHI and urban area size, and doubling the urban area size led to a SUHI increase of higher than 0.7 °C. The response of SUHI to the increase of urban area size shows spatial and temporal variations, with stronger SUHI increase in the Northern region of U.S., and during daytime and summer. Urban area size alone can explain as much as 87% of the variance of SUHI among cities studied, but with large spatial and temporal variations. Urban area size shows higher association with SUHI in regions where the thermal characteristics of land cover surrounding the urban are more homogeneous, such as in Eastern U.S., and in the summer months. This study provides a

  2. Numerical investigation of the energy performance of an Opaque Ventilated Façade system employing a smart modular heat recovery unit and a latent heat thermal energy system

    International Nuclear Information System (INIS)

    Diallo, Thierno M.O.; Zhao, Xudong; Dugue, Antoine; Bonnamy, Paul; Javier Miguel, Francisco; Martinez, Asier; Theodosiou, Theodoros; Liu, Jing-Sheng; Brown, Nathan

    2017-01-01

    Highlights: •An innovative E2VENT ventilated façade system is presented and modelled with TRNSYS. •The energy efficiency of the system is assessed for five climates in Europe. •The E2VENT retrofitting system is compared with a traditional retrofit method. •The E2VENT system achieves 16.5–23.5% primary energy saving. •The E2VENT system saves twice as much primary energy as the traditional retrofit. -- Abstract: The building sector is responsible for more than 40% of the EU’s total energy consumption. To reduce the energy consumption in buildings and to achieve the EU’s fossil fuel saving targets for 2020 and beyond 2050, the energy efficient retrofitting strategies are critically important and need to be implemented effectively. This paper presents a dynamic numerical investigation of the energy performance of an innovative façade integrate-able energy efficient ventilation system (E2VENT) that incorporates a smart modular heat recovery unit (SMHRU) and a latent heat thermal energy system (LHTES). A number of component simulation models, including SMHRU, LHTES, Cladding and Building Energy Management System (BEMS), were developed and then integrated using the TRNSYS software which is an advanced building energy performance simulation tool. On this basis, sizing, optimisation and characterisation of the system elements including the HVAC system and insulation layer thickness were carried out. The overall energy efficiency of the E2VENT system and its impact on the energy performance of a post-retrofit building were then investigated. In particular, the heating and cooling energy performance of the E2VENT façade module was numerically studied at five different climatic conditions in Europe. Furthermore, the innovative E2VENT retrofitting was compared with traditional retrofittings in terms of the energy efficiency and primary energy savings. It was found that the innovative E2VENT solution can achieve 16.5–23.5% building primary energy saving and

  3. Microwave processing heats up

    Science.gov (United States)

    Microwaves are a common appliance in many households. In the United States microwave heating is the third most popular domestic heating method food foods. Microwave heating is also a commercial food processing technology that has been applied for cooking, drying, and tempering foods. It's use in ...

  4. Control system pre-feedbacked for the super heated steam temperature in heat recovering units; Sistema de control pre-retroalimentado para la temperatura de vapor sobrecalentado en recuperadores de calor

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Alvarez, Hilario; Madrigal Espinosa, Guadalupe [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The study that is presented corresponds to the analysis, design and development of a pre-feedbacked control system for the superheated steam temperature regulation in the heat recovery units of a combined cycle thermoelectric power plant. The designs of the feedback controller and the pre-feedback control system were implemented based in a linear model of the tempering zone. This linear model was obtained through the application of parametric identification techniques to the non-linear mathematical model of a combined cycle power plant. [Espanol] El estudio que se presenta corresponde al analisis, diseno y desarrollo de un sistema de control pre-retroalimentado para regular la temperatura de vapor sobrecalentado en los recuperadores de calor de una central termoelectrica de ciclo combinado. Los disenos del controlador retroalimentado y del sistema de control prealimentado se realizaron con base en un modelo lineal de la zona de atemperacion. Este modelo lineal se obtuvo aplicando tecnicas de identificacion parametrica al modelo matematico no-lineal de una central de ciclo combinado.

  5. Control system pre-feedbacked for the super heated steam temperature in heat recovering units; Sistema de control pre-retroalimentado para la temperatura de vapor sobrecalentado en recuperadores de calor

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Alvarez, Hilario; Madrigal Espinosa, Guadalupe [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The study that is presented corresponds to the analysis, design and development of a pre-feedbacked control system for the superheated steam temperature regulation in the heat recovery units of a combined cycle thermoelectric power plant. The designs of the feedback controller and the pre-feedback control system were implemented based in a linear model of the tempering zone. This linear model was obtained through the application of parametric identification techniques to the non-linear mathematical model of a combined cycle power plant. [Espanol] El estudio que se presenta corresponde al analisis, diseno y desarrollo de un sistema de control pre-retroalimentado para regular la temperatura de vapor sobrecalentado en los recuperadores de calor de una central termoelectrica de ciclo combinado. Los disenos del controlador retroalimentado y del sistema de control prealimentado se realizaron con base en un modelo lineal de la zona de atemperacion. Este modelo lineal se obtuvo aplicando tecnicas de identificacion parametrica al modelo matematico no-lineal de una central de ciclo combinado.

  6. Utilising heat from nuclear waste for space heating

    International Nuclear Information System (INIS)

    Deacon, D.

    1982-01-01

    A heating unit utilising the decay heat from irradiated material comprises a storage envelope for the material associated with a heat exchange system, means for producing a flow of air over the heat exchange system to extract heat from the material, an exhaust duct capable of discharging the heated air to the atmosphere, and means for selectively diverting at least some of the heated air to effect the required heating. With the flow of air over the heat exchange system taking place by a natural thermosyphon process the arrangement is self regulating and inherently reliable. (author)

  7. Plate heat exchangers in air conditioning applications. Development of air-coolers, air-heaters and air-conditioning units with low pressure loss. Plattenwaermetauscher in raumlufttechnischen Anlagen. Entwicklung stroemungsoptimierter Luftkuehler, Lufterhitzer und Klimageraete

    Energy Technology Data Exchange (ETDEWEB)

    Bach, H; Diemer, R; Eisenmann, G; Goettling, D; Madjidi, M

    1989-08-01

    To prepare the development of a water to air plate heat exchanger the state of the art, i.e. the technological knowhow and the design basis are given. The concept and ideas are presented which lead to a slightly wavy plate. Furthermore an exemplary design of a plate heat exchanger and an air-conditioning unit is described and finally the application of plate heat exchangers as direct evaporators and the potential icing problems are investigated. Comparing measured and calculated data shows that the performance of plates with plane surfaces can be predicted fairly well by the presented design methods. The performance of plates with strongly wavy surface however has to be measured. Optimization calculations yield to an air gap of slightly over 4 mm. Comparison with an air-conditioning unit demonstrates that the strongest advantage is for the air cooler (one third of the pressure loss) that a new concept of an air-conditioning unit has lower losses in the fan unit and that it does not need an eliminator. This results in half the volume for the new unit, in a pressure drop of 88%, fan power of 90% and fan revolutions of 50%. (orig./GL).

  8. Optimal usage of low temperature heat sources to supply district heating by heat pumps

    DEFF Research Database (Denmark)

    Pieper, Henrik; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2017-01-01

    This paper presents a theoretical study on the optimal usage of different low temperature heat sources to supply district heating by heat pumps. The study is based on data for the Copenhagen region. The heat sources were prioritized based on the coefficient of performance calculated for each hour...... and the covered demand of each heat source as well as required peak unit capacity. The results showed that heat pumps using different heat sources yield better performance than a heat pump based on a single one. The performance was influenced by the composition of the different heat sources. It was found that 78......% groundwater, 22% seawater and 0% air resulted in highest COP of 3.33 for the given heat demand. Furthermore, the implementation of rule based short term storage made peak units redundant. The variation in base load capacity showed that heat pumps utilizing the analyzed heat sources could perform very...

  9. Heat and power from combustibles

    International Nuclear Information System (INIS)

    Zogg, M.

    2002-01-01

    This article compares four ways of generating heat and power from liquid and gaseous fuels. Various combinations of conventional boilers, heat pumps, combined heat and power units and combined-cycle power plants are considered and the ratio of heat to electrical power produced is discussed. Fuel requirements for the four combinations are looked at and net emissions of carbon dioxide, oxides of nitrogen and carbon monoxide presented in graphical form. The author makes recommendations on the choice of the technology to be used to generate heat and electricity for different heat/power ratios and criticises the all too slack emission limits for small combined heat and power units

  10. Industrial excess heat for district heating in Denmark

    International Nuclear Information System (INIS)

    Bühler, Fabian; Petrović, Stefan; Karlsson, Kenneth; Elmegaard, Brian

    2017-01-01

    Highlights: •Method for utilisation potential of industrial excess heat for district heating. •Industrial excess heat from thermal processes is quantified at single production units. •Linking of industrial excess heat sources and district heating demands done in GIS. •Excess heat recovery using direct heat transfer and heat pumps. •5.1% of the Danish district heating demand could be supplied by industrial excess heat. -- Abstract: Excess heat is available from various sources and its utilisation could reduce the primary energy use. The accessibility of this heat is however dependent amongst others on the source and sink temperature, amount and potential users in its vicinity. In this work a new method is developed which analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal processes which equals 5.1% of the current demand. More than half of this heat was found to be usable directly, without the need for a heat pump.

  11. Effect of enhanced ultraviolet germicidal irradiation in the heating ventilation and air conditioning system on ventilator-associated pneumonia in a neonatal intensive care unit.

    Science.gov (United States)

    Ryan, R M; Wilding, G E; Wynn, R J; Welliver, R C; Holm, B A; Leach, C L

    2011-09-01

    The objective of this study was to test the hypothesis that enhanced ultraviolet germicidal irradiation (eUVGI) installed in our neonatal intensive care unit (NICU) heating ventilation and air conditioning system (HVAC) would decrease HVAC and NICU environment microbes, tracheal colonization and ventilator-associated pneumonia (VAP). The study was designed as a prospective interventional pre- and post-single-center study. University-affiliated Regional Perinatal Center NICU. Intubated patients in the NICU were evaluated for colonization, and a high-risk sub-population of infants <30 weeks gestation ventilated for ≥ 14 days was studied for VAP. eUVGI was installed in the NICU's remote HVACs. The HVACs, NICU environment and intubated patients' tracheas were cultured pre- and post-eUVGI for 12 months. The high-risk patients were studied for VAP (positive bacterial tracheal culture, increased ventilator support, worsening chest radiograph and ≥ 7 days of antibiotics). Pseudomonas, Klebsiella, Serratia, Acinetobacter, Staphylococcus aureus and Coagulase-negative Staphylococcus species were cultured from all sites. eUVGI significantly decreased HVAC organisms (baseline 500,000 CFU cm(-2); P=0.015) and NICU environmental microbes (P<0.0001). Tracheal microbial loads decreased 45% (P=0.004), and fewer patients became colonized. VAP in the high-risk cohort fell from 74% (n=31) to 39% (n=18), P=0.04. VAP episodes per patient decreased (Control: 1.2 to eUVGI: 0.4; P=0.004), and antibiotic usage was 62% less (P=0.013). eUVGI decreased HVAC microbial colonization and was associated with reduced NICU environment and tracheal microbial colonization. Significant reductions in VAP and antibiotic use were also associated with eUVGI in this single-center study. Large randomized multicenter trials are needed.

  12. Heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Harada, F; Yanagida, T; Fujie, K; Futawatari, H

    1975-04-30

    The purpose of this construction is the improvement of heat transfer in finned tube heat exchangers, and therefore the improvement of its efficiency or its output per unit volume. This is achieved by preventing the formation of flow boundary layers in gaseous fluid. This effect always occurs on flow of smooth adjacent laminae, and especially if these have pipes carrying liquid passing through them; it worsens the heat transfer of such a boundary layer considerably compared to that in the turbulent range. The fins, which have several rows of heat exchange tubes passing through them, are fixed at a small spacing on theses tubes. The fins have slots cut in them by pressing or punching, where the pressed-out material remains as a web, which runs parallel to the level of the fin and at a small distance from it. These webs and slots are arranged radially around every tube hole, e.g. 6 in number. For a suitable small tube spacing, two adjacent tubes opposite each other have one common slot. Many variants of such slot arrangements are illustrated.

  13. The health effects of hotter summers and heat waves in the population of the United Kingdom: a review of the evidence.

    Science.gov (United States)

    Arbuthnott, Katherine G; Hajat, Shakoor

    2017-12-05

    It is widely acknowledged that the climate is warming globally and within the UK. In this paper, studies which assess the direct impact of current increased temperatures and heat-waves on health and those which project future health impacts of heat under different climate change scenarios in the UK are reviewed.This review finds that all UK studies demonstrate an increase in heat-related mortality occurring at temperatures above threshold values, with respiratory deaths being more sensitive to heat than deaths from cardiovascular disease (although the burden from cardiovascular deaths is greater in absolute terms). The relationship between heat and other health outcomes such as hospital admissions, myocardial infarctions and birth outcomes is less consistent. We highlight the main populations who are vulnerable to heat. Within the UK, these are older populations, those with certain co-morbidities and those living in Greater London, the South East and Eastern regions.In all assessments of heat-related impacts using different climate change scenarios, deaths are expected to increase due to hotter temperatures, with some studies demonstrating that an increase in the elderly population will also amplify burdens. However, key gaps in knowledge are found in relation to how urbanisation and population adaptation to heat will affect health impacts, and in relation to current and future strategies for effective, sustainable and equitable adaptation to heat. These and other key gaps in knowledge, both in terms of research needs and knowledge required to make sound public- health policy, are discussed.

  14. Heat pumps: heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Pielke, R

    1976-01-01

    The author firstly explains in a general manner the functioning of the heat pump. Following a brief look at the future heat demand and the possibilities of covering it, the various methods of obtaining energy (making use of solar energy, ground heat, and others) and the practical applications (office heating, swimming pool heating etc.) are explained. The author still sees considerable difficulties in using the heat pump at present on a large scale. Firstly there is not enough maintenance personnel available, secondly the electricity supply undertakings cannot provide the necessary electricity on a wide basis without considerable investments. Other possibilities to save energy or to use waste energy are at present easier and more economical to realize. Recuperative and regenerative systems are described.

  15. Industrial excess heat for district heating in Denmark

    DEFF Research Database (Denmark)

    Bühler, Fabian; Petrovic, Stefan; Karlsson, Kenneth Bernard

    2017-01-01

    analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate...... the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity...... analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal...

  16. Environmental and energy efficiency evaluation of residential gas and heat pump heating

    International Nuclear Information System (INIS)

    Ganji, A.R.

    1993-01-01

    Energy efficiency and source air pollutant emission factors of gas heaters, gas engine heat pumps, and electric heat pumps for domestic heating have been evaluated and compared. The analysis shows that with the present state of technology, gas engine heat pumps have the highest energy efficiency followed by electric heat pumps and then gas heaters. Electric heat pumps produce more than twice as much NO x , and comparable CO 2 and CO per unit of useful heating energy compared to natural gas heaters. CO production per unit of useful heating energy from gas engine heat pumps without any emission control is substantially higher than electric heat pumps and natural gas heaters. NO x production per unit of useful heating energy from natural gas engine heat pumps (using lean burn technology) without any emission control is about the same as effective NO x production from electric heat pumps. Gas engine heat pumps produce about one-half CO 2 compared to electric heat pumps

  17. Heat pipe heat storage performance

    Energy Technology Data Exchange (ETDEWEB)

    Caruso, A; Pasquetti, R [Univ. de Provence, Marseille (FR). Inst. Universitaire des Systemes; Grakovich, L P; Vasiliev, L L [A.V. Luikov Heat and Mass Transfer Inst. of the BSSR, Academy of Sciences, Minsk (BY)

    1989-01-01

    Heat storage offers essential thermal energy saving for heating. A ground heat store equipped with heat pipes connecting it with a heat source and to the user is considered in this paper. It has been shown that such a heat exchanging system along with a batch energy source meets, to a considerable extent, house heating requirements. (author).

  18. Result of comparative experiment on environmental comfort in room using hot heat environment testing unit. Onnetsu kankyo shiken unit ni yoru shitsunai kankyo no kaitekisa no hikaku jikken kekka ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, T; Kawashima, K [The Hokkaido Electric Power Co. Inc., Sapporo (Japan)

    1991-11-20

    Measurements were carried out on three buildings having different heat insulation, airtightness and heat capacity for testing the hot heast enviroments (having a room size of about 4.6 m{times}3.7m{times}2.3 m) as to the temperature differences between the upper and lower parts of the room and the MRT (mean radiation temperature, representing the temperature of radiation from the wall face). These are compared according to types of heating appliance. The result is summarize as follows: The temperature difference in the upper and lower parts is affected largely by the airtightness of the building, the difference being capable of getting reduced by rasing the airtightness even in a buildings low in heat insulation. In a building with low airtightness, type of heating appliance and its installation location affect the temperature difference. The MRT is determined determined nearly completely by the heat insulation of the wall face in a room, but it tends to be affected easily by the specification and area of windows. A floor heating system increases the MRT and generates very little difference in temperatures in the upper and lower parts of the room. A comparison using a PMV (one of the indexes for enviromental comfort in a room) was also conducted. 12 figs., 7tabs.

  19. Heat transfer

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Heat transfer. Heat conduction in solid slab. Convective heat transfer. Non-linear temperature. variation due to flow. HEAT FLUX AT SURFACE. conduction/diffusion.

  20. Heat Waves

    Science.gov (United States)

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and spasms due ... that the body is having trouble with the heat. If a heat wave is predicted or happening… - ...

  1. Heat Islands

    Science.gov (United States)

    EPA's Heat Island Effect Site provides information on heat islands, their impacts, mitigation strategies, related research, a directory of heat island reduction initiatives in U.S. communities, and EPA's Heat Island Reduction Program.

  2. Miniature Heat Pipes

    Science.gov (United States)

    1997-01-01

    Small Business Innovation Research contracts from Goddard Space Flight Center to Thermacore Inc. have fostered the company work on devices tagged "heat pipes" for space application. To control the extreme temperature ranges in space, heat pipes are important to spacecraft. The problem was to maintain an 8-watt central processing unit (CPU) at less than 90 C in a notebook computer using no power, with very little space available and without using forced convection. Thermacore's answer was in the design of a powder metal wick that transfers CPU heat from a tightly confined spot to an area near available air flow. The heat pipe technology permits a notebook computer to be operated in any position without loss of performance. Miniature heat pipe technology has successfully been applied, such as in Pentium Processor notebook computers. The company expects its heat pipes to accommodate desktop computers as well. Cellular phones, camcorders, and other hand-held electronics are forsible applications for heat pipes.

  3. Champagne Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    2004-01-01

    The term champagne heat pump denotes a developmental heat pump that exploits a cycle of absorption and desorption of carbon dioxide in an alcohol or other organic liquid. Whereas most heat pumps in common use in the United States are energized by mechanical compression, the champagne heat pump is energized by heating. The concept of heat pumps based on other absorption cycles energized by heat has been understood for years, but some of these heat pumps are outlawed in many areas because of the potential hazards posed by leakage of working fluids. For example, in the case of the water/ammonia cycle, there are potential hazards of toxicity and flammability. The organic-liquid/carbon dioxide absorption/desorption cycle of the champagne heat pump is similar to the water/ammonia cycle, but carbon dioxide is nontoxic and environmentally benign, and one can choose an alcohol or other organic liquid that is also relatively nontoxic and environmentally benign. Two candidate nonalcohol organic liquids are isobutyl acetate and amyl acetate. Although alcohols and many other organic liquids are flammable, they present little or no flammability hazard in the champagne heat pump because only the nonflammable carbon dioxide component of the refrigerant mixture is circulated to the evaporator and condenser heat exchangers, which are the only components of the heat pump in direct contact with air in habitable spaces.

  4. Decentralized central heating

    Energy Technology Data Exchange (ETDEWEB)

    Savic, S.; Hudjera, A.

    1994-08-04

    The decentralized central heating is essentially based on new technical solutions for an independent heating unit, which allows up to 20% collectible energy savings and up to 15% savings in built-in-material. These savings are already made possible by the fact that the elements described under point A are thus eliminated from the classical heating. The thus superfluous made elements are replaced by new technical solutions described under point B - technical problem - and point E - patent claim. The technical solutions described in detail under point B and point E form together a technical unit and are essential parts of the invention protected by the patent. (author)

  5. Solar heating system

    Science.gov (United States)

    Schreyer, James M.; Dorsey, George F.

    1982-01-01

    An improved solar heating system in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75.degree. to 180.degree. F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing and releasing heat for distribution.

  6. Improved solar heating systems

    Science.gov (United States)

    Schreyer, J.M.; Dorsey, G.F.

    1980-05-16

    An improved solar heating system is described in which the incident radiation of the sun is absorbed on collector panels, transferred to a storage unit and then distributed as heat for a building and the like. The improvement is obtained by utilizing a storage unit comprising separate compartments containing an array of materials having different melting points ranging from 75 to 180/sup 0/F. The materials in the storage system are melted in accordance with the amount of heat absorbed from the sun and then transferred to the storage system. An efficient low volume storage system is provided by utilizing the latent heat of fusion of the materials as they change states in storing ad releasing heat for distribution.

  7. Heat jettisoning from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water; Waermeabwurf aus einer solarthermisch getriebenen LiBr- H{sub 2}O Absorptionskaeltemaschine durch gepulstes Bespruehen eines Trockenkuehlers mit Wasser

    Energy Technology Data Exchange (ETDEWEB)

    Gantenbein, P.; Helfenberger, R.; Frank, E.

    2010-07-01

    This short, illustrated final report discusses the removal of heat from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water. The reduction of electricity consumption for room cooling using conventional chillers is examined. Heat dissipation using open cooling towers and the disadvantages encountered are compared with heat dissipation using a dry cooler with heat-exchanger and fans. Additional evaporation cooling achieved by spraying the heat exchanger with water is described and discussed. The results of measurements made at the Institute for Solar Technology in Rapperswil, Switzerland, are presented and discussed.

  8. Heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, E L; Eisenmann, G; Hahne, E [Stuttgart Univ. (TH) (F.R. Germany). Inst. fuer Thermodynamik und Waermetechnik

    1976-04-01

    A survey is presented on publications on design, heat transfer, form factors, free convection, evaporation processes, cooling towers, condensation, annular gap, cross-flowed cylinders, axial flow through a bundle of tubes, roughnesses, convective heat transfer, loss of pressure, radiative heat transfer, finned surfaces, spiral heat exchangers, curved pipes, regeneraters, heat pipes, heat carriers, scaling, heat recovery systems, materials selection, strength calculation, control, instabilities, automation of circuits, operational problems and optimization.

  9. Analysis of the heat transfer mechanisms during energy storage in a Phase Change Material filled vertical finned cylindrical unit for free cooling application

    International Nuclear Information System (INIS)

    Solomon, Gnanadurai Ravikumar; Velraj, Ramalingam

    2013-01-01

    Highlights: • Freezing behavior of a PCM, in a cylinder with annular longitudinal fins is presented. • Among various fin heights, 20 mm fin contribute maximum heat transfer enhancement. • Addition of fins plays a contradictory role during the sensible cooling of liquid PCM. • The fin effect along with external cooling, vary the sensible cooling rate of liquid PCM. • The surface convective resistance dominated over the conductive resistance of PCM. - Abstract: The heat transfer performance of the Phase Change Material (PCM) used in free cooling application is low due to poor thermal conductivity. The addition of fins to enhance the heat transfer during solidification process is commonly employed, to address this. However for application such as free cooling, where the driving temperature potential is very less, the present experimental study is intended to investigate the sensible and subcooling phenomena during the outward cylindrical solidification of the PCM stored on the annulus side, along with 8 longitudinal uniformly spaced copper fins of different heights. The performance of the fins during solidification is analyzed, and the best suitable height is arrived at. The addition of fins plays a contradicting role during the sensible cooling of the liquid PCM, due to the suppression of free convection. The external cooling conditions along with the effect of the fin, vary the sensible cooling rate of the liquid PCM, that influences the subcooling effect, and also drifts the temperature at which major phase change occurs. In addition, the effects due to the inlet velocity of the heat transfer fluid, and its temperature on heat transfer are investigated and reported. The increase in velocity decreases the duration of solidification, and this effect is more pronounced towards the entry region, due to the higher local convective heat transfer co-efficient and a comparatively higher driving temperature potential

  10. Incorporation of a Helical Tube Heat Transfer Model in the MARS Thermal Hydraulic Systems Analysis Code for the T/H Analyses of the SMART Reactor

    International Nuclear Information System (INIS)

    Young Jin Lee; Bub Dong Chung; Jong Chull Jo; Hho Jung Kim; Un Chul Lee

    2004-01-01

    SMART is a medium sized integral type advanced pressurized water reactor currently under development at KAERI. The steam generators of SMART are designed with helically coiled tubes and these are designed to produce superheated steam. The helical shape of the tubes can induce strong centrifugal effect on the secondary coolant as it flows inside the tubes. The presence of centrifugal effect is expected to enhance the formation of cross-sectional circulation flows within the tubes that will increase the overall heat transfer. Furthermore, the centrifugal effect is expected to enhance the moisture separation and thus make it easier to produce superheated steam. MARS is a best-estimate thermal-hydraulic systems analysis code with multi-phase, multi-dimensional analysis capability. The MARS code was produced by restructuring and merging the RELAP5 and the COBRA-TF codes. However, MARS as well as most other best-estimate systems analysis codes in current use lack the detailed models needed to describe the thermal hydraulics of helically coiled tubes. In this study, the heat transfer characteristics and relevant correlations for both the tube and shell sides of helical tubes have been investigated, and the appropriate models have been incorporated into the MARS code. The newly incorporated helical tube heat transfer package is available to the MARS users via selection of the appropriate option in the input. A performance analysis on the steam generator of SMART under full power operation was carried out using the modified MARS code. The results of the analysis indicate that there is a significant improvement in the code predictability. (authors)

  11. Heat recovery system series arrangements

    Science.gov (United States)

    Kauffman, Justin P.; Welch, Andrew M.; Dawson, Gregory R.; Minor, Eric N.

    2017-11-14

    The present disclosure is directed to heat recovery systems that employ two or more organic Rankine cycle (ORC) units disposed in series. According to certain embodiments, each ORC unit includes an evaporator that heats an organic working fluid, a turbine generator set that expands the working fluid to generate electricity, a condenser that cools the working fluid, and a pump that returns the working fluid to the evaporator. The heating fluid is directed through each evaporator to heat the working fluid circulating within each ORC unit, and the cooling fluid is directed through each condenser to cool the working fluid circulating within each ORC unit. The heating fluid and the cooling fluid flow through the ORC units in series in the same or opposite directions.

  12. Primary energy savings using heat storage for biomass heating systems

    Directory of Open Access Journals (Sweden)

    Mitrović Dejan M.

    2012-01-01

    Full Text Available District heating is an efficient way to provide heat to residential, tertiary and industrial users. The heat storage unit is an insulated water tank that absorbs surplus heat from the boiler. The stored heat in the heat storage unit makes it possible to heat even when the boiler is not working, thus increasing the heating efficiency. In order to save primary energy (fuel, the boiler operates on nominal load every time it is in operation (for the purpose of this research. The aim of this paper is to analyze the water temperature variation in the heat storage, depending on the heat load and the heat storage volume. Heat load is calculated for three reference days, with average daily temperatures from -5 to 5°C. The primary energy savings are also calculated for those days in the case of using heat storage in district heating.[Projekat Ministarstva nauke Republike Srbije, br. TR 33051: The concept of sustainable energy supply of settlements with energy efficient buildings

  13. Heat Stress

    Science.gov (United States)

    ... Publications and Products Programs Contact NIOSH NIOSH HEAT STRESS Recommend on Facebook Tweet Share Compartir OSHA-NIOSH ... hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational ...

  14. Research of the heat exchanging processes running in the heating and hot water supply loops of the coil heat exchangers

    Directory of Open Access Journals (Sweden)

    Ірина Геннадіївна Шитікова

    2016-11-01

    Full Text Available The fuel-energy complex research has made it possible to disclose a huge power-saving potential in the municipal heat-and-power engineering. Power-and-resource-saving units and systems are becoming extremely urgent because of the power engineering crisis expansion. The self-adjusting heat supply system from the individual heating points with the heat-accumulating units and coil heat exchangers for independent heating and water supply systems has been examined. Coil heat exchangers are used in municipal heating for heat transfer (e.g. geothermal waters for the independent mains of the heating and hot water supply systems. The heat engineering calculation of the heating and accumulating unit with the coil heat exchanger for independent heat supply systems from individual heater was performed and experimental data were received at the experimental industrial unit under the laboratory conditions. The peculiarities of the flows in the intertubular space, their influence on the heat exchange and temperatures of the first and intermediate mains have been shown. It is important to know the processes running inside the apparatus to be able to improve the technical characteristics of the three-loop coil heat exchanger. The task solution will make it possible to save the materials consumption for the three-loop coil heat exchangers in the future

  15. Solar/electric heating systems for the future energy system

    DEFF Research Database (Denmark)

    Furbo, Simon; Dannemand, Mark; Perers, Bengt

    elements/heat pump, advanced heat storage tanks and advanced control systems. Heat is produced by solar collectors in sunny periods and by electrical heating elements/heat pump. The electrical heating elements/heat pump will be in operation in periods where the heat demand cannot be covered by solar energy....... The aim is to use the auxiliary heating units when the electricity price is low, e.g. due to large electricity production by wind turbines. The unit is equipped with an advanced control system where the control of the auxiliary heating is based on forecasts of the electricity price, the heat demand...

  16. Non-linear model predictive supervisory controller for building, air handling unit with recuperator and refrigeration system with heat waste recovery

    DEFF Research Database (Denmark)

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

    2016-01-01

    . The retrieved heat excess can be stored in the water tank. For this purpose the charging and the discharging water loops has been designed. We present the non-linear model of the above described system and a non-linear model predictive supervisory controller 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 controllers of supermarkets subsystems. We find that when reliable information about the high price period is available, it is profitable to use the refrigeration system...... to generate heat during the low price period, store it and use it to substitute the conventional heater during the high price period....

  17. A Study on Heat-up Phenomena of the RHR Pump Room in KORI Unit 2 for the Loss of HVAC Accidents

    International Nuclear Information System (INIS)

    Yoon, Churl; Park, Jin Hee; Lim, Ho Gon; Han, Sang Hoon

    2009-01-01

    In PSA(Probabilistic Safety Analysis) Models, the HVAC(Heating, Ventilation, and Air Condition) system is essential for the various vital mitigation safety systems operating during a mission time. So far, the unavailability of a safety system when the HVAC system fails has been applied conservatively or optimistically based on operating experience and expert judgment, so the total core damage frequency could be unrealistic. When the HVAC system of a nuclear power plant fails, it is one of the main issues in a PSA FT (Fault Tree) model to estimate the transient temperature variations of some component rooms. The purpose of this study is to establish a heat-up prediction model by using direct measuring and CFD(Computational Fluid Dynamics) analyses

  18. Design of A District Heating System Including The Upgrading of Residual Industrial Waste Heat

    NARCIS (Netherlands)

    Falcao, P.W.; Mesbah, A.; Suherman, M.V.; Wennekes, S.

    2005-01-01

    This study was aimed to evaluate the feasibility of using a waste heat stream from DSM for a District Heating System. A conceptual design was carried out with emphasis on the unit for upgrading the residual waste heat. Having reviewed heat pump technology, mechanical heat pump was found to be the

  19. Cooldown to residual heat removal entry conditions using atmospheric dump valves and auxiliary pressurizer spray following a loss-of-offsite power at Calvert Cliffs, Unit 1

    International Nuclear Information System (INIS)

    Jenks, R.P.

    1984-01-01

    An investigation of cooldown using atmospheric dump valves (ADVs) and auxiliary pressurizer spray (APS) following loss-of-offsite power at Calvert Cliffs-1 showed residual heat removal entry conditions could not be reached with the plant ADVs alone. Use of APS with the plant ADVs enhanced depressurization, but still provided insufficient cooldown. Effective cooldown and depressurization was shown to occur when rated steady state flow through the ADVs was increased by a factor of four. 6 refs., 30 figs., 2 tabs

  20. Simulation of heat and mass transfer processes in the experimental section of the air-condensing unit of Scientific Production Company "Turbocon"

    Science.gov (United States)

    Artemov, V. I.; Minko, K. B.; Yan'kov, G. G.; Kiryukhin, A. V.

    2016-05-01

    A mathematical model was developed to be used for numerical analysis of heat and mass transfer processes in the experimental section of the air condenser (ESAC) created in the Scientific Production Company (SPC) "Turbocon" and mounted on the territory of the All-Russia Thermal Engineering Institute. The simulations were performed using the author's CFD code ANES. The verification of the models was carried out involving the experimental data obtained in the tests of ESAC. The operational capability of the proposed models to calculate the processes in steam-air mixture and cooling air and algorithms to take into account the maldistribution in the various rows of tube bundle was shown. Data on the influence of temperature and flow rate of the cooling air on the pressure in the upper header of ESAC, effective heat transfer coefficient, steam flow distribution by tube rows, and the dimensions of the ineffectively operating zones of tube bundle for two schemes of steam-air mixture flow (one-pass and two-pass ones) were presented. It was shown that the pressure behind the turbine (in the upper header) increases significantly at increase of the steam flow rate and reduction of the flow rate of cooling air and its temperature rise, and the maximum value of heat transfer coefficient is fully determined by the flow rate of cooling air. Furthermore, the steam flow rate corresponding to the maximum value of heat transfer coefficient substantially depends on the ambient temperature. The analysis of the effectiveness of the considered schemes of internal coolant flow was carried out, which showed that the two-pass scheme is more effective because it provides lower pressure in the upper header, despite the fact that its hydraulic resistance at fixed flow rate of steam-air mixture is considerably higher than at using the one-pass schema. This result is a consequence of the fact that, in the two-pass scheme, the condensation process involves the larger internal surface of tubes

  1. Heat pumps

    CERN Document Server

    Macmichael, DBA

    1988-01-01

    A fully revised and extended account of the design, manufacture and use of heat pumps in both industrial and domestic applications. Topics covered include a detailed description of the various heat pump cycles, the components of a heat pump system - drive, compressor, heat exchangers etc., and the more practical considerations to be taken into account in their selection.

  2. Fighting fire in the heat of the day: An analysis of operational and environmental conditions of use for large airtankers in United States fire suppression

    Science.gov (United States)

    Crystal S. Stonesifer; Dave Calkin; Matthew P. Thompson; Keith D. Stockmann

    2016-01-01

    Large airtanker use is widespread in wildfire suppression in the United States. The current approach to nationally dispatching the fleet of federal contract airtankers relies on filling requests for airtankers to achieve suppression objectives identified by fire managers at the incident level. In general, demand is met if resources are available, and the...

  3. A synopsis of the wood-based energy and heating industries in the northeastern United States with consideration of potential impacts on future demand for roundwood

    Science.gov (United States)

    Jan Wiedenback; Chuck D. Ray; Li. Ma

    2011-01-01

    The project team identified 323 facilities in the northeastern United States that input pulpwood or "energy wood." Of these, 88 are located in Pennsylvania, Ohio, and West Virginia, part of the central hardwood forest region. In the 13-state northeastern region, 81 percent of the facilities that use pulp-type roundwood produce an energy-related product. For...

  4. IEA HPP Annex 42 Heat Pumps in Smart Grids - Task 1 Market Overview United States: ORNL/TM-2014/73

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sikes, Karen [SRA International, Inc., Fairfax, VA (United States); Domitrovic, Ronald [Electric Power Research Institute (EPRI), Palo Alto, CA (United States); Amrane, Karim [Air-Conditioning, Heating, and Refrigeration Inst., Arlington, VA (United States)

    2014-04-01

    As a result of the American Recovery and Reinvestment Act of 2009 (ARRA), rapid deployment of smart meters occurred between 2009 and 2012 in the United States. Now that this large amount of advanced metering infrastructure is installed, utilities are revisiting how to best incorporate them into operations to enhanced power distribution.

  5. 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...

  6. Fuel fired heat sources

    Energy Technology Data Exchange (ETDEWEB)

    Ortlinghaus, U

    1977-09-08

    Fuel fired heat sources with a valve-controlled ignition and main burner, whose flame is monitored and whose control valve is closed or opened by a controller according to the control deviation between actual and reference heat source temperature, previously suffered the disadvantage of high consumption of ignition gas. According to the invention this disadvantage is avoided by closing the ignition valve from the controller via a delay unit and having the delay time of the delay unit controlled either by the temperature measured by the sensor or increasing it with increasing deviation of the actual value of pre-temperature from the reference value of the pre-temperature.

  7. Investigation of four problems on the units of material and its properties, energy with heat and temperature in the secondary school physics textbooks

    Science.gov (United States)

    Kavcar, Nevzat; Özen, Ali Ihsan

    2017-02-01

    In the present study, three units in textbooks in accordance with the 2013 Secondary School Physics Curriculum were analyzed in defined four problems, and some recommendations were made. The study carried out in the Spring semester of education year 2015-2016, within the scope of an undergraduate course. Method of the study is the descriptive model based on qualitative research technics. The data collection instruments were textbook evaluation reports prepared by the participants and pre-service teachers, and presentations reflecting teachers' and pre-service teachers' ideas on the textbooks. A document analysis was conducted by means of these data collection tools. It has been concluded that in the related units a significant shortcoming is not found regarding being student-centered, activity and contex-based approximations. However, some shortcomings were found in activity-gain concordance with measurement and evaluation applications. On the basis of the collected data, some recommendations for improving the textbooks have been presented.

  8. Failure study of helium-cooled tungsten divertor plasma-facing units tested at DEMO relevant steady-state heat loads

    International Nuclear Information System (INIS)

    Ritz, G; Pintsuk, G; Linke, J; Hirai, T; Norajitra, P; Reiser, J; Giniyatulin, R; Makhankov, A; Mazul, I

    2009-01-01

    Tungsten was selected as armor material for the helium-cooled divertor in future DEMO-type fusion reactors and fusion power plants. After realizing the design and testing of them under cyclic thermal loads of up to ∼14 MW m -2 , the tungsten divertor plasma-facing units were examined by metallography; they revealed failures such as cracks at the thermal loaded and as-machined surfaces, as well as degradation of the brazing layers. Furthermore, in order to optimize the machining processes, the quality of tungsten surfaces prepared by turning, milling and using a diamond cutting wheel were examined. This paper presents a metallographic examination of the tungsten plasma-facing units as well as technical studies and the characterization on machining of tungsten and alternative brazing joints.

  9. Failure study of helium-cooled tungsten divertor plasma-facing units tested at DEMO relevant steady-state heat loads

    Science.gov (United States)

    Ritz, G.; Hirai, T.; Norajitra, P.; Reiser, J.; Giniyatulin, R.; Makhankov, A.; Mazul, I.; Pintsuk, G.; Linke, J.

    2009-12-01

    Tungsten was selected as armor material for the helium-cooled divertor in future DEMO-type fusion reactors and fusion power plants. After realizing the design and testing of them under cyclic thermal loads of up to ~14 MW m-2, the tungsten divertor plasma-facing units were examined by metallography; they revealed failures such as cracks at the thermal loaded and as-machined surfaces, as well as degradation of the brazing layers. Furthermore, in order to optimize the machining processes, the quality of tungsten surfaces prepared by turning, milling and using a diamond cutting wheel were examined. This paper presents a metallographic examination of the tungsten plasma-facing units as well as technical studies and the characterization on machining of tungsten and alternative brazing joints.

  10. Heat pumps

    CERN Document Server

    Brodowicz, Kazimierz; Wyszynski, M L; Wyszynski

    2013-01-01

    Heat pumps and related technology are in widespread use in industrial processes and installations. This book presents a unified, comprehensive and systematic treatment of the design and operation of both compression and sorption heat pumps. Heat pump thermodynamics, the choice of working fluid and the characteristics of low temperature heat sources and their application to heat pumps are covered in detail.Economic aspects are discussed and the extensive use of the exergy concept in evaluating performance of heat pumps is a unique feature of the book. The thermodynamic and chemical properties o

  11. Effectiveness of heating, ventilation and air conditioning system with HEPA filter unit on indoor air quality and asthmatic children's health

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying; Raja, Suresh; Ferro, Andrea R.; Jaques, Peter A.; Hopke, Philip K. [Clarkson University, 8 Clarkson Avenue, Center for Air Resources Engineering and Science, Potsdam, NY 13699 (United States); Gressani, Cheryl; Wetzel, Larry E. [Air Innovations, Inc, 7000 Performance Drive, North Syracuse, NY 13212 (United States)

    2010-02-15

    Poor indoor air quality has been linked to the exacerbation of asthma symptoms in children. Because people spend most of their time indoors, improving indoor air quality may provide some relief to asthma sufferers. A study was conducted to assess whether operating an air cleaning/ventilating unit (HEPAiRx {sup registered}) in a child's bedroom can improve his/her respiratory health. Thirty children diagnosed with asthma were randomly split into two groups. For the first six weeks, group A had the air cleaning/ventilating unit (HEPAiRx {sup registered}) running in the bedrooms of the participants and group B did not; for the second six weeks, both groups had the cleaners running in the bedrooms; and, for the final six weeks, group A turned the cleaners off and group B kept theirs running. Indoor air quality parameters, including temperature, relative humidity, particulate matter (PM 0.5-10 {mu}m), carbon monoxide, carbon dioxide and total volatile organic compound (TVOC) concentrations, were monitored in each bedroom using an AirAdvice indoor air quality multi-meter. As a measure of pulmonary inflammation, exhaled breath condensate (EBC) was collected every sixth day and analyzed for nitrate and pH. Peak expiratory flow (PEF) was also measured. PM and TVOC concentrations decreased with operation of the HEPAiRx an average of 72% and 59%, respectively. The EBC nitrate concentrations decreased significantly and the EBC pH and PEF values increased significantly with operation of the unit (p < 0.001 when comparing on/off sample means). These results indicate that air cleaning in combination with ventilation can effectively reduce symptoms for asthma sufferers. (author)

  12. Heat Capacity Analysis Report

    International Nuclear Information System (INIS)

    Findikakis, A.

    2004-01-01

    The purpose of this report is to provide heat capacity values for the host and surrounding rock layers for the waste repository at Yucca Mountain. The heat capacity representations provided by this analysis are used in unsaturated zone (UZ) flow, transport, and coupled processes numerical modeling activities, and in thermal analyses as part of the design of the repository to support the license application. Among the reports that use the heat capacity values estimated in this report are the ''Multiscale Thermohydrologic Model'' report, the ''Drift Degradation Analysis'' report, the ''Ventilation Model and Analysis Report, the Igneous Intrusion Impacts on Waste Packages and Waste Forms'' report, the ''Dike/Drift Interactions report, the Drift-Scale Coupled Processes (DST and TH Seepage) Models'' report, and the ''In-Drift Natural Convection and Condensation'' report. The specific objective of this study is to determine the rock-grain and rock-mass heat capacities for the geologic stratigraphy identified in the ''Mineralogic Model (MM3.0) Report'' (BSC 2004 [DIRS 170031], Table 1-1). This report provides estimates of the heat capacity for all stratigraphic layers except the Paleozoic, for which the mineralogic abundance data required to estimate the heat capacity are not available. The temperature range of interest in this analysis is 25 C to 325 C. This interval is broken into three separate temperature sub-intervals: 25 C to 95 C, 95 C to 114 C, and 114 C to 325 C, which correspond to the preboiling, trans-boiling, and postboiling regimes. Heat capacity is defined as the amount of energy required to raise the temperature of a unit mass of material by one degree (Nimick and Connolly 1991 [DIRS 100690], p. 5). The rock-grain heat capacity is defined as the heat capacity of the rock solids (minerals), and does not include the effect of water that exists in the rock pores. By comparison, the rock-mass heat capacity considers the heat capacity of both solids and pore

  13. Heat transfer

    International Nuclear Information System (INIS)

    Saad, M.A.

    1985-01-01

    Heat transfer takes place between material systems as a result of a temperature difference. The transmission process involves energy conversions governed by the first and second laws of thermodynamics. The heat transfer proceeds from a high-temperature region to a low-temperature region, and because of the finite thermal potential, there is an increase in entropy. Thermodynamics, however, is concerned with equilibrium states, which includes thermal equilibrium, irrespective of the time necessary to attain these equilibrium states. But heat transfer is a result of thermal nonequilibrium conditions, therefore, the laws of thermodynamics alone cannot describe completely the heat transfer process. In practice, most engineering problems are concerned with the rate of heat transfer rather than the quantity of heat being transferred. Resort then is directed to the particular laws governing the transfer of heat. There are three distinct modes of heat transfer: conduction, convection, and radiation. Although these modes are discussed separately, all three types may occur simultaneously

  14. Heat exchanger

    Science.gov (United States)

    Daman, Ernest L.; McCallister, Robert A.

    1979-01-01

    A heat exchanger is provided having first and second fluid chambers for passing primary and secondary fluids. The chambers are spaced apart and have heat pipes extending from inside one chamber to inside the other chamber. A third chamber is provided for passing a purge fluid, and the heat pipe portion between the first and second chambers lies within the third chamber.

  15. Assessing the impacts of droughts and heat waves at thermoelectric power plants in the United States using integrated regression, thermodynamic, and climate models

    Directory of Open Access Journals (Sweden)

    Margaret A. Cook

    2015-11-01

    Full Text Available Recent droughts and heat waves have revealed the vulnerability of some power plants to effects from higher temperature intake water for cooling. In this evaluation, we develop a methodology for predicting whether power plants are at risk of violating thermal pollution limits. We begin by developing a regression model of average monthly intake temperatures for open loop and recirculating cooling pond systems. We then integrate that information into a thermodynamic model of energy flows within each power plant to determine the change in cooling water temperature that occurs at each plant and the relationship of that water temperature to other plants in the river system. We use these models together with climate change models to estimate the monthly effluent temperature at twenty-six power plants in the Upper Mississippi River Basin and Texas between 2015 and 2035 to predict which ones are at risk of reaching thermal pollution limits. The intake model shows that two plants could face elevated intake temperatures between 2015 and 2035 compared to the 2010–2013 baseline. In general, a rise in ambient cooling water temperature of 1 °C could cause a drop in power output of 0.15%–0.5%. The energy balance shows that twelve plants might exceed state summer effluent limits.

  16. A combination of Stirling engine and high-efficiency boiler. Microsize cogeneration unit for heat and power supply; Stirlingmotor und Brennwertkessel vereint. Mikro-Waermekraftkopplung liefert Strom und Waerme

    Energy Technology Data Exchange (ETDEWEB)

    Donnerbauer, R.

    2001-03-01

    Apart from the heat pump and fuel cell, there is another new development: At the ISH in March, the Dutch producer EnAtEc intends to present a microsize cogeneration unit consisting of a gas-fuelled high-efficiency boiler and a free-piston Stirling motor. [German] Sind die Wirkungsgrade in der Heiztechnik ausgenutzt? Auf die Frage 'Was kommt nach der Brennwerttechnik?' gibt es jetzt neben Waermepumpe und Brennstoffzelle eine neue Antwort. Zur kommenden ISH Ende Maerz hat die niederlaendische Firma EnAtEc die Vorstellung einer 'Mikro-Waermekraftkopplung' ({mu}WK) angekuendigt. Das Geraet kombiniert einen Gas-Brennwertkessel mit einer Freikolben-Stirlingmaschine. (orig.)

  17. Thermal construction unit activation with supply air gains significance. Ceilings cooling - supply air heating - more than 50 % energy conservation; Thermische Bauteilaktivierung mit Zuluft gewinnt an Bedeutung. Decke kuehlen - Zuluft erwaermen - mehr als 50% Energie einsparen

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Wolfgang

    2009-05-15

    In the year 2001, in Stuttgart (Federal Republic of Germany) the first office building was established which uses a thermal construction unit activation with air as cooling agent. Today, the system ''Concret-cool'' already is installed in more than 40 buildings. Computations show that due to the room heating by means of internally finned ventilation pipes embedded in concrete more than 50 % less energy in comparison to comparable systems can be used. In his Green Building project ''Skyline Tower'' in Munich (Federal Republic of Germany), also star architect Helmut Jahn uses the know-how of the manufacturer of ventilation systems from Stuttgart. As one of the first multi-storied buildings in Munich, ''Skyline Tower'' with its 23 floors was prized with the pre-certificate of the German quality seal ''sustainable building ''in gold.

  18. Loss of vital ac power and the residual heat removal system during mid-loop operations at Vogtle Unit 1 on March 20, 1990

    International Nuclear Information System (INIS)

    1990-06-01

    On March 20, 1990, the Vogtle Electric Generating Plant Unit 1, located in Burke County, Georgia, about 25 miles southeast of Augusta, experienced a loss of all safety (vital) ac power. The plant was in cold shutdown with reactor coolant level lowered to ''mid-loop'' for various maintenance tasks. Both the containment building personnel hatch and equipment hatch were open. One emergency diesel generator and one reserve auxiliary transformer were out of service for maintenance, with the remaining reserve auxiliary transformer supplying both Unit 1 safety buses. A truck in the low voltage switchyard backed into the support column for an offsite power feed to the reserve auxiliary transformer which was supplying safety power. The insulator broke, a phase-to-ground fault occurred, and the feeder circuit breakers for the safety buses opened. The operable emergency diesel generator started automatically because of the undervoltage condition on the safety bus, but tripped off after about 1 minute. About 20 minutes later the diesel generator load sequencer was reset, causing the diesel generator to start a second time. The diesel generator operated for about 1 minute, and tripped off. The diesel generator was restarted in the manual emergency mode 36 minutes after the loss of power. The generator remained on line and provided power to its safety bus. During the 36 minutes without safety bus power, the reactor coolant system temperature rose from about 90 degree F to 136 degree F. This report documents the results of an Incident Investigation Team sent to Vogtle by the Executive Director for Operations of the US Nuclear Regulatory Commission to determine what happened, identify the probable causes, and make appropriate findings and conclusions. 79 figs., 16 tabs

  19. Heat pipe

    International Nuclear Information System (INIS)

    Triggs, G.W.; Lightowlers, R.J.; Robinson, D.; Rice, G.

    1986-01-01

    A heat pipe for use in stabilising a specimen container for irradiation of specimens at substantially constant temperature within a liquid metal cooled fast reactor, comprises an evaporator section, a condenser section, an adiabatic section therebetween, and a gas reservoir, and contains a vapourisable substance such as sodium. The heat pipe further includes a three layer wick structure comprising an outer relatively fine mesh layer, a coarse intermediate layer and a fine mesh inner layer for promoting unimpeded return of condensate to the evaporation section of the heat pipe while enhancing heat transfer with the heat pipe wall and reducing entrainment of the condensate by the upwardly rising vapour. (author)

  20. Process integration study of a kraft pulp mill converted to an ethanol production plant – Part A: Potential for heat integration of thermal separation units

    International Nuclear Information System (INIS)

    Fornell, Rickard; Berntsson, Thore

    2012-01-01

    Energy efficiency is an important parameter for the profitability of biochemical ethanol production from lignocellulosic raw material. The yield of ethanol is generally low due to the limited amount of fermentable compounds in the raw material. Increasing energy efficiency leads to possibilities of exporting more by-products, which in turn might reduce the net production cost of ethanol. Energy efficiency is also an important issue when discussing the repurposing of kraft pulp mills to biorefineries, since the mills in question most likely will be old and inefficient. Investing in energy efficiency measures might therefore have a large effect on the economic performance. This paper discusses energy efficiency issues related to the repurposing of a kraft pulp mill into a lignocellulosic ethanol production plant. The studied process is a typical Scandinavian kraft pulp mill that has been converted to a biorefinery with ethanol as main product. A process integration study, using pinch analysis and process simulations, has been performed in order to assess alternative measures for improving the energy efficiency. The improvements found have also been related to the possibilities for by-product sales from the plant (electricity and/or lignin). In a forthcoming paper, which is the second part of this process integration study, an economic analysis based on the results from this paper will be presented. - Highlights: ► Conversion of a kraft pulp mill to ethanol production. ► Heat integration of distillation/evaporation in a lignocellulosic ethanol plant. ► Advanced pinch curves used to find new integration possibilities. ► 35–40% reduction of steam demand.

  1. HEAT PUMP USING SUBSOIL WATERS AS LOW TEMPERATURE HEAT SOURCE

    Directory of Open Access Journals (Sweden)

    Denysova Alla

    2015-08-01

    Full Text Available One of the basic directions of perfection of heat supply systems is the tendency of transition to the low-temperature heating systems based on application of heat pump installations. We consider heat supply system with heat pump installations using subsoil waters. Numerical simulation of thermal processes in the elements of a single-stage and double-stage heat pump systems has been worked out. Values of depths of wells and their quantity, necessary for effective operation of the offered installations, and values of capacity of electric water pumps for subsoil waters unit are calculated. Capacity of compressor electric drive and coefficient of performance of heat pump for the conditions of the city of Odessa are presented.

  2. Chapter 11. Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Rafferty, Kevin D.; Culver, Gene

    1998-01-01

    Most geothermal fluids, because of their elevated temperature, contain a variety of dissolved chemicals. These chemicals are frequently corrosive toward standard materials of construction. As a result, it is advisable in most cases to isolate the geothermal fluid from the process to which heat is being transferred. The task of heat transfer from the geothermal fluid to a closed process loop is most often handled by a plate heat exchanger. The two most common types used in geothermal applications are: bolted and brazed. For smaller systems, in geothermal resource areas of a specific character, downhole heat exchangers (DHEs) provide a unique means of heat extraction. These devices eliminate the requirement for physical removal of fluid from the well. For this reason, DHE-based systems avoid entirely the environmental and practical problems associated with fluid disposal. Shell and tube heat exchangers play only a minor role in low-temperature, direct-use systems. These units have been in common use in industrial applications for many years and, as a result, are well understood. For these reasons, shell and tube heat exchangers will not be covered in this chapter.

  3. Heat and fluid flow in accident of Fukushima Daiichi Nuclear Power Plant, Unit 3. Behaviour of high pressure coolant injection system (HPCI) based on thermodynamic model

    International Nuclear Information System (INIS)

    Maruyama, Shigenao

    2014-01-01

    In order to clarify the process of Accident of Fukushima Nuclear Plants, an accident scenario of Fukushima Daiichi Nuclear Power Plant, Unit 3 is analyzed from the data open to the public. Phase equilibrium process model was introduced in which the vapor and water are at saturation point in the vessels. The present accident scenario assumes that the high pressure coolant injection system (HPCI) did not worked properly, but the steam in the reactor pressure vessel (RPV) leaked through the turbine of HPCI to the suppression chamber since 12/3/2011 12:35. It is assumed that the Tsunami flooded the torus room where the suppression chamber was placed. Proposed accident scenario agrees with the data of the plant parameters obtained just after the accident. It is estimated that the water injection by HPIC was stopped since around at 13/3 19:00 and the water level in RPV decreased since then. It is estimated that the RPV broke at 14/3 8:55 and water could injected from fire engines due to the depression due to the rupture of RPV. There was little water left in RPV at the time of the rupture. If the present scenario is correct, the behavior that operators in the plant stopped HPCI at 13/3 2:42 did not affect seriously on the RPV rupture. If HPCI was working properly until the operators stopped it, the plant parameters obtained in the accident cannot be explained. (author)

  4. Heat Roadmap Europe 3 (STRATEGO)

    DEFF Research Database (Denmark)

    Connolly, David; Hansen, Kenneth; Drysdale, David

    Heat Roadmap Europe 3 is from work package 2 of the STRATEGO project (http://stratego-project.eu/). It quantifies the impact of implementing various energy efficiency measures in the heating and cooling sectors of five EU Member States: Czech Republic, Croatia, Italy, Romania, and the United...... of approximately €1.1 trillion in energy efficiency measures across all five of these countries, between 2010 and 2050, will save enough fuel to reduce the costs of their energy systems. After considering both the initial investment and the resulting savings, the total annual cost of the heating, cooling......, and electricity sectors is reduced by an average of ~15% in each country. These initial investments are primarily required in heat savings for the buildings, district heating in urban areas, and electric heat pumps in rural areas. In essence, energy efficiency measures in the heating sector will enable EU Member...

  5. Comparison of silorane and methacrylate-based composites on the polymerization heat generated with different light-curing units and dentin thicknesses.

    Science.gov (United States)

    Guiraldo, Ricardo Danil; Consani, Simonides; Consani, Rafael Leonardo Xediek; Berger, Sandrine Bittencourt; Correr, Américo Bortolazzo; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço

    2013-01-01

    This study evaluated the temperature variation in the pulp chamber during photoactivation of two restorative composite resins (Filtek P90 silorane-based composite and Heliomolar methacrylate-based composite) with either a quartz-tungsten-halogen (QTH) or light-emitting diodes (LED) light-curing unit (LCU) and using dentin thicknesses (0.5 and 1.0 mm). Standardized cavities (2x2x2 mm) were prepared in 80 bovine incisors, which were randomly assigned to 8 groups according to the photoactivation method and dentin thickness. Filtek P90 and Heliomolar (both in shade A3) were used with their respective adhesive systems (P90 self-etch primer / P90 adhesive bond and Excite adhesive). All experiments were carried out in a controlled environment (37°C). The temperature variations (°C) were recorded using a digital thermometer attached to a K-type thermocouple. The results were analyzed statistically by ANOVA and Tukey's test (α=0.05). For composite/dentin thickness interaction, temperature increase was significantly higher in 0.5 mm dentin thickness (40.07°C) compared with 1.0 mm dentin thickness (39.61°C) for Filtek P90. For composite/LCU interaction, the temperature increase was significantly higher for Filtek P90 (39.21°C - QTH and 40.47°C - LED) compared with Heliomolar (38.40°C - QTH and 39.30°C - LED). The silorane-based composite promoted higher temperature increase in the pulp chamber than the methacrylate-based composite.

  6. Geothermal heat pump performance

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Tonya L.; Lienau, Paul J.

    1995-01-01

    Geothermal heat pump systems are a promising new energy technology that has shown rapid increase in usage over the past ten years in the United States. These systems offer substantial benefits to customers and utilities in energy (kWh) and demand (kW) savings. The purpose of this study was to determine what existing monitored data was available mainly from electric utilities on heat pump performance, energy savings and demand reduction for residential, school, and commercial building applications. Information was developed on the status of electric utility marketing programs, barriers to market penetration, incentive programs, and benefits.

  7. Geothermal Heat Pump Performance

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Tonya L.; Lienau, Paul J.

    1995-01-01

    Geothermal heat pump systems are a promising new energy technology that has shown rapid increase in usage over the past ten years in the United States. These systems offer substantial benefits to customers and utilities in energy (kWh) and demand (kW) savings. The purpose of this study was to determine what existing monitored data was available mainly from electric utilities on heat pump performance, energy savings and demand reduction for residential, school, and commercial building applications. Information was developed on the status of electric utility marketing programs, barriers to market penetration, incentive programs, and benefits.

  8. Heat exchanger

    International Nuclear Information System (INIS)

    Leigh, D.G.

    1976-01-01

    The arrangement described relates particularly to heat exchangers for use in fast reactor power plants, in which heat is extracted from the reactor core by primary liquid metal coolant and is then transferred to secondary liquid metal coolant by means of intermediate heat exchangers. One of the main requirements of such a system, if used in a pool type fast reactor, is that the pressure drop on the primary coolant side must be kept to a minimum consistent with the maintenance of a limited dynamic head in the pool vessel. The intermediate heat exchanger must also be compact enough to be accommodated in the reactor vessel, and the heat exchanger tubes must be available for inspection and the detection and plugging of leaks. If, however, the heat exchanger is located outside the reactor vessel, as in the case of a loop system reactor, a higher pressure drop on the primary coolant side is acceptable, and space restriction is less severe. An object of the arrangement described is to provide a method of heat exchange and a heat exchanger to meet these problems. A further object is to provide a method that ensures that excessive temperature variations are not imposed on welded tube joints by sudden changes in the primary coolant flow path. Full constructional details are given. (U.K.)

  9. Plasma heating

    International Nuclear Information System (INIS)

    Wilhelm, R.

    1989-01-01

    Successful plasma heating is essential in present fusion experiments, for the demonstration of DpT burn in future devices and finally for the fusion reactor itself. This paper discusses the common heating systems with respect to their present performance and their applicability to future fusion devices. The comparative discussion is oriented to the various function of heating, which are: - plasma heating to fusion-relevant parameters and to ignition in future machines, -non-inductive, steady-pstate current drive, - plasma profile control, -neutral gas breakdown and plasma build-up. In view of these different functions, the potential of neutral beam injection (NBI) and the various schemes of wave heating (ECRH, LH, ICRH and Alven wave heating) is analyzed in more detail. The analysis includes assessments of the present physical and technical state of these heating methods, and makes suggestions for future developments and about outstanding problems. Specific attention is given to the still critical problem of efficient current drive, especially with respect to further extrapolation towards an economically operating tokamak reactor. Remarks on issues such as reliability, maintenance and economy conclude this comparative overview on plasma heating systems. (author). 43 refs.; 13 figs.; 3 tabs

  10. Analysis of the heat transfer in double and triple concentric tube heat exchangers

    Science.gov (United States)

    Rădulescu, S.; Negoiţă, L. I.; Onuţu, I.

    2016-08-01

    The tubular heat exchangers (shell and tube heat exchangers and concentric tube heat exchangers) represent an important category of equipment in the petroleum refineries and are used for heating, pre-heating, cooling, condensation and evaporation purposes. The paper presents results of analysis of the heat transfer to cool a petroleum product in two types of concentric tube heat exchangers: double and triple concentric tube heat exchangers. The cooling agent is water. The triple concentric tube heat exchanger is a modified constructive version of double concentric tube heat exchanger by adding an intermediate tube. This intermediate tube improves the heat transfer by increasing the heat area per unit length. The analysis of the heat transfer is made using experimental data obtained during the tests in a double and triple concentric tube heat exchanger. The flow rates of fluids, inlet and outlet temperatures of water and petroleum product are used in determining the performance of both heat exchangers. Principally, for both apparatus are calculated the overall heat transfer coefficients and the heat exchange surfaces. The presented results shows that triple concentric tube heat exchangers provide better heat transfer efficiencies compared to the double concentric tube heat exchangers.

  11. Urban Heat Wave Hazard Assessment

    Science.gov (United States)

    Quattrochi, Dale A.; Jedlovec, Gary; Meyer, Paul J.; LaFontaine, Frank J.; Crane, Dakota L.

    2016-01-01

    Heat waves are the largest cause of environment-related deaths globally. On average, over 6,000 people in the United States alone are hospitalized each summer due to excessive heat. Key elements leading to these disasters are elevated humidity and the urban heat island effect, which act together to increase apparent temperature and amplify the effects of a heat wave. Urban demographics and socioeconomic factors also play a role in determining individual risk. Currently, advisories of impending heat waves are often too generalized, with limited or no spatial variability over urban regions. This frequently contributes to a lack of specific response on behalf of the population. A goal of this project is to develop a product that has the potential to provide more specific heat wave guidance invoking greater awareness and action.

  12. Acclimatization to extreme heat

    Science.gov (United States)

    Warner, M. E.; Ganguly, A. R.; Bhatia, U.

    2017-12-01

    Heat extremes throughout the globe, as well as in the United States, are expected to increase. These heat extremes have been shown to impact human health, resulting in some of the highest levels of lives lost as compared with similar natural disasters. But in order to inform decision makers and best understand future mortality and morbidity, adaptation and mitigation must be considered. Defined as the ability for individuals or society to change behavior and/or adapt physiologically, acclimatization encompasses the gradual adaptation that occurs over time. Therefore, this research aims to account for acclimatization to extreme heat by using a hybrid methodology that incorporates future air conditioning use and installation patterns with future temperature-related time series data. While previous studies have not accounted for energy usage patterns and market saturation scenarios, we integrate such factors to compare the impact of air conditioning as a tool for acclimatization, with a particular emphasis on mortality within vulnerable communities.

  13. Open heat exchanger for improved heat efficiency in geothermal spas

    Energy Technology Data Exchange (ETDEWEB)

    Nasrabady, S.J.; Palsson, H.; Saevarsdottir, G.A.

    2008-09-15

    Hot spas and Jacuzzis are popular in Iceland due to the abundance of reasonably prized geothermal heat available. However the water from the district heating system is too warm to be admitted directly into the spa. For safety reasons the water is mixed with cold water, in order to reduce temperature from about 80 deg C down to 45 deg C, which leads to wasting a large quantity of heat. Therefore a design is suggested here that enables the feeding of geothermal water directly into the spa, omitting the step of mixing it with cold water. The idea is to employ an open heat exchanger that transfers heat from the geothermal water to the bulk water in the spa, before letting it mix with the spa water. A case study was done for one particular spa. Heat load was calculated and measured when the spa was in use, and when it was unused. A design is suggested employing a circular double-plate which is to be placed at the bottom of the spa. This unit will function as an open heat exchanger feeding district heating water into the spa. Free convection takes place at the upper side of the upper plate and forced convection below the upper plate. Heat transfer coefficient for both was calculated. Using results from calculations, temperature distribution at critical parts of spa and plate was modeled. Results are reasonable and promising for a good design that may considerably reduce the energy expenses for a continuously heated geothermal spa

  14. 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...... production, due to low gas turbine outlet temperature, space and weight restrictions and the need for make-up water. A more promising option for use offshore is organic Rankine cycles (ORC). Moreover, several oil and gas platforms are equipped with waste heat recovery units to recover a part of the thermal...... energy in the gas turbine off-gas using heat exchangers, and the recovered thermal energy acts as heat source for some of the heat loads on the platform. The amount of the recovered thermal energy depends on the heat loads and thus the full potential of waste heat recovery units may not be utilized...

  15. Heat pipes

    CERN Document Server

    Dunn, Peter D

    1994-01-01

    It is approximately 10 years since the Third Edition of Heat Pipes was published and the text is now established as the standard work on the subject. This new edition has been extensively updated, with revisions to most chapters. The introduction of new working fluids and extended life test data have been taken into account in chapter 3. A number of new types of heat pipes have become popular, and others have proved less effective. This is reflected in the contents of chapter 5. Heat pipes are employed in a wide range of applications, including electronics cooling, diecasting and injection mo

  16. Heat conduction

    International Nuclear Information System (INIS)

    Grigull, U.; Sandner, H.

    1984-01-01

    Included are discussions of rates of heat transfer by conduction, the effects of varying and changing properties, thermal explosions, distributed heat sources, moving heat sources, and non-steady three-dimensional conduction processes. Throughout, the importance of thinking both numerically and symbolically is stressed, as this is essential to the development of the intuitive understanding of numerical values needed for successful designing. Extensive tables of thermophysical properties, including thermal conductivity and diffusivity, are presented. Also included are exact and approximate solutions to many of the problems that arise in practical situations

  17. Induced current heating probe

    International Nuclear Information System (INIS)

    Thatcher, G.; Ferguson, B.G.; Winstanley, J.P.

    1984-01-01

    An induced current heating probe is of thimble form and has an outer conducting sheath and a water flooded flux-generating unit formed from a stack of ferrite rings coaxially disposed in the sheath. The energising coil is made of solid wire which connects at one end with a coaxial water current tube and at the other end with the sheath. The stack of ferrite rings may include non-magnetic insulating rings which help to shape the flux. (author)

  18. Heat pumps in western Switzerland

    International Nuclear Information System (INIS)

    Freymond, A.

    2003-01-01

    The past ten years have seen an extraordinary expansion of heat-pump market figures in the western (French speaking) part of Switzerland. Today, more than 14,000 units are in operation. This corresponds to about 18% of all the machines installed in the whole country, compared to only 10 to 12% ten years ago. This success illustrates the considerable know-how accumulated by the leading trade and industry during these years. It is also due to the promotional program 'Energy 2000' of the Swiss Federal Department of Energy that included the heat pump as a renewable energy source. Already in 1986, the Swiss Federal Institute of Technology in Lausanne was equipped with a huge heat pump system comprising two electrically driven heat pumps of 3.5 MW thermal power each. The heat source is water drawn from the lake of Geneva at a depth of 70 meters. An annual coefficient of performance of 4.5 has been obtained since the commissioning of the plant. However, most heat pump installations are located in single-family dwellings. The preferred heat source is geothermal heat, using borehole heat exchangers and an intermediate heat transfer fluid. The average coefficient of performance of these installations has been increased from 2.5 in 1995 to 3.1 in 2002

  19. District heating

    International Nuclear Information System (INIS)

    Hansen, L.

    1993-01-01

    The environmental risks and uncertainties of a high-energy future are disturbing and give rise to several reservations concerning the use of fossil fuels. A number of technologies will help to reduce atmospheric pollution. In Denmark special importance is attached to the following: Energy conservation. Efficient energy conversion. Renewable energy sources. District heating, combined production of heat and power. Many agree that district heating (DH), produced by the traditional heat-only plant, and combined heat and power (CHP) have enormous potential when considering thermal efficiency and lowered environmental impacts: The basic technology of each is proven, it would be relatively simple to satisfy a substantial part of the energy demand, and their high efficiencies mean reduced pollution including greenhouse gas emissions. This is especially important in high population density areas - the obviously preferred sites for such energy generation. Compared with individual heating DH can provide a community with an operationally efficient and most often also an economically competitive heat supply. This is particularly true under the circumstances where the DH system is supplied from CHP plants. Their use results in very substantial improvements in overall efficiency. Further environmental improvements arise from the reduced air pollution obtainable in reasonably large CHP plants equipped with flue gas cleaning to remove particles, sulphur dioxide, and nitrogen acids. As a consequence of these considerations, DH plays an important role in fulfilling the space and water heating demand in many countries. This is especially the case in Denmark where this technology is utilised to a very great extent. Indeed, DH is one of the reasons why Denmark has relatively good air quality in the cities. (au)

  20. Solar heating and cooling of buildings

    Science.gov (United States)

    Bourke, R. D.; Davis, E. S.

    1975-01-01

    Solar energy has been used for space heating and water heating for many years. A less common application, although technically feasible, is solar cooling. This paper describes the techniques employed in the heating and cooling of buildings, and in water heating. The potential for solar energy to displace conventional energy sources is discussed. Water heating for new apartments appears to have some features which could make it a place to begin the resurgence of solar energy applications in the United States. A project to investigate apartment solar water heating, currently in the pilot plant construction phase, is described.

  1. Research of waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water

    Science.gov (United States)

    Zhang, Li; Zhang, Yu; Zhou, Liansheng; E, Zhijun; Wang, Kun; Wang, Ziyue; Li, Guohao; Qu, Bin

    2018-02-01

    The waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water has been analyzed. After the operation of heat pump, the influences on power generation and heat generation of unit were taken into account. In the light of the characteristics of heat pump in different operation stages, the energy efficiency of heat pump was evaluated comprehensively on both sides of benefits belonging to electricity and benefits belonging to heat, which adopted the method of contrast test. Thus, the reference of energy efficiency for same type projects was provided.

  2. Cleaning Schedule Operations in Heat Exchanger Networks

    Directory of Open Access Journals (Sweden)

    Huda Hairul

    2018-01-01

    Full Text Available Heat exchanger networks have been known to be the essential parts in the chemical industries. Unfortunately, since the performance of heat exchanger can be decreasing in transferring the heat from hot stream into cold stream due to fouling, then cleaning the heat exchanger is needed to restore its initial performance periodically. A process of heating crude oil in a refinery plant was used as a case study. As many as eleven heat exchangers were used to heat crude oil before it was heated by a furnace to the temperature required to the crude unit distillation column. The purpose of this study is to determine the cleaning schedule of heat exchanger on the heat exchanger networks due to the decrease of the overall heat transfer coefficient by various percentage of the design value. A close study on the process of heat exchanger cleaning schedule in heat exchanger networks using the method of decreasing overall heat transfer coefficient as target. The result showed that the higher the fouling value the more often the heat exchanger is cleaned because the overall heat transfer coefficient decreases quickly.

  3. Experimental investigation on Heat Transfer Performance of Annular Flow Path Heat Pipe

    International Nuclear Information System (INIS)

    Kim, In Guk; Kim, Kyung Mo; Jeong, Yeong Shin; Bang, In Cheol

    2015-01-01

    Mochizuki et al. was suggested the passive cooling system to spent nuclear fuel pool. Detail analysis of various heat pipe design cases was studied to determine the heat pipes cooling performance. Wang et al. suggested the concept PRHRS of MSR using sodium heat pipes, and the transient performance of high temperature sodium heat pipe was numerically simulated in the case of MSR accident. The meltdown at the Fukushima Daiichi nuclear power plants alarmed to the dangers of station blackout (SBO) accident. After the SBO accident, passive decay heat removal systems have been investigated to prevent the severe accidents. Mochizuki et al. suggested the heat pipes cooling system using loop heat pipes for decay heat removal cooling and analysis of heat pipe thermal resistance for boiling water reactor (BWR). The decay heat removal systems for pressurized water reactor (PWR) were suggested using natural convection mechanisms and modification of PWR design. Our group suggested the concept of a hybrid heat pipe with control rod as Passive IN-core Cooling System (PINCs) for decay heat removal for advanced nuclear power plant. Hybrid heat pipe is the combination of the heat pipe and control rod. In the present research, the main objective is to investigate the effect of the inner structure to the heat transfer performance of heat pipe containing neutron absorber material, B 4 C. The main objective is to investigate the effect of the inner structure in heat pipe to the heat transfer performance with annular flow path. ABS pellet was used instead of B 4 C pellet as cylindrical structures. The thermal performances of each heat pipes were measured experimentally. Among them, concentric heat pipe showed the best performance compared with others. 1. Annular evaporation section heat pipe and annular flow path heat pipe showed heat transfer degradation. 2. AHP also had annular vapor space and contact cooling surface per unit volume of vapor was increased. Heat transfer coefficient of

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

    International Nuclear Information System (INIS)

    Saneipoor, P.; Naterer, G.F.; Dincer, I.

    2011-01-01

    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 CO 2 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.

  5. Review: heat pipe heat exchangers at IROST

    OpenAIRE

    E. Azad

    2012-01-01

    The use of the heat pipe as a component in a heat recovery device has gained worldwide acceptance. Heat pipes are passive, highly reliable and offer high heat transfer rates. This study summarizes the investigation of different types of heat pipe heat recovery systems (HPHRSs). The studies are classified on the basis of the type of the HPHRS. This research is based on 30 years of experience on heat pipe and heat recovery systems that are presented in this study. Copyright , Oxford University ...

  6. Unwanted heat

    International Nuclear Information System (INIS)

    Benka, M.

    2006-01-01

    The number of small heating plants using biomass is growing. According to TREND's information, Hrinovska energeticka, is the only one that controls the whole supplier chain in cooperation with its parent company in Bratislava. Starting with the collection and processing of wood chips by burning, heat production and heat distribution to the end user. This gives the company better control over costs and consequently its own prices. Last year, the engineering company, Hrinovske storjarne, decided to focus only on its core business and sold its heating plant, Hrinovske tepelne hospodarstvo, to Intech Slovakia and changed the company name to Hrinovska energeticka. Local companies and inhabitants were concerned that the new owner would increase prices. But the company publicly declared and kept promises that the heat price for households would remain at 500 Slovak crowns/gigajoule (13.33 EUR/gigajoule ), one of the lowest prices in Slovakia. This year the prices increased slightly to 570 Slovak crowns (15.2 EUR). 'We needed - even at the cost of lower profit - to satisfy our customers so that we would not lose them. We used this time for transition to biomass. This will allow us to freeze our prices in the coming years,' explained the statutory representative of the company, Ivan Dudak. (authors)

  7. Heat Pipes

    Science.gov (United States)

    1990-01-01

    Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than 57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was 28,706, and that figures out to a cost reduction.

  8. Residential CO{sub 2} heat pump system for combined space heating and hot water heating

    Energy Technology Data Exchange (ETDEWEB)

    Stene, Joern

    2004-02-01

    the inlet water temperature for the Dh preheating gas cooler unit. The lower the inlet temperature, the higher the Cop. The CO{sub 2} system will therefore achieve the highest COP at low city water temperatures, and when there is negligible mixing and minimum conductive heat transfer between the hot and cold water in the DHW tank during the tapping and charging periods. (5) The COP for the integrated CO{sub 2} heat pump is generally more sensitive to variations in the compressor efficiency than that of conventional brine/water-to-water heat pump systems. It is therefore of particular importance to apply a high-efficiency compressor. (6) At each operating mode and temperature programme, there will be an optimum gas cooler (high-side) pressure that leads to a maximum COP for the integrated CO{sub 2} heat pump. However, at moderate DHW temperatures, the heat pump can be operated at constant high-side pressure in all heating modes with only a minor reduction in the COP. This is favourable, since it simplifies the operation of the system and reduces the first cost. (7) During operation in the combined heating mode, the COP for the integrated CO{sub 2} heat pump may be higher than in the DHW heating mode due to similar temperature approaches at the cold outlet of the gas coolers and lower optimum high-side pressure. The higher the DHW temperature, the larger the COP difference for the operating modes. (8) The integrated CO{sub 2} heat pump system will be more complex than the state-of-the art residential heat pump systems due to the requirement for a tripartite gas cooler, extra valves and tubing for by-pass of fluids, an inverter controlled pump in the DHW circuit as well as an especially designed DHW storage tank. The application of optimum high-side pressure control will further increase the technical and operational complexity of the system. (9) Conductive heat transfer between the DHW and the cold city water in the storage tank during the tapping and charging periods

  9. Design of common heat exchanger network for batch processes

    International Nuclear Information System (INIS)

    Anastasovski, Aleksandar

    2014-01-01

    Heat integration of energy streams is very important for the efficient energy recovery in production systems. Pinch technology is a very useful tool for heat integration and maximizing energy efficiency. Creating of heat exchangers network as a common solution for systems in batch mode that will be applicable in all existing time slices is very difficult. This paper suggests a new methodology for design of common heat exchanger network for batch processes. Heat exchanger network designs were created for all determined repeatable and non-repeatable time periods – time slices. They are the basis for creating the common heat exchanger network. The common heat exchanger network as solution, satisfies all heat-transfer needs for each time period and for every existing combination of selected streams in the production process. This methodology use split of some heat exchangers into two or more heat exchange units or heat exchange zones. The reason for that is the multipurpose use of heat exchangers between different pairs of streams in different time periods. Splitting of large heat exchangers would maximize the total heat transfer usage of heat exchange units. Final solution contains heat exchangers with the minimum heat load as well as the minimum need of heat transfer area. The solution is applicable for all determined time periods and all existing stream combinations. - Highlights: •Methodology for design of energy efficient systems in batch processes. •Common Heat Exchanger Network solution based on designs with Pinch technology. •Multipurpose use of heat exchangers in batch processes

  10. Heating experiments of JT-60

    International Nuclear Information System (INIS)

    1987-01-01

    In JT-60, after the finish of the first stage Joule experiment, the heating facilities were installed, and the heating experiment was started in August, 1986. As to neutral beam injection, the beam injection experiment at the maximum rating 20 MW carried out, and also as to RF, the injection experiment up to 1.4 MW was carried out in both ion cyclotron and low band hybrid waves. The results worthy of special mention in the heating experiment were the success in the current drive up to 1.7 MA at maximum using low band hybrid waves and the improvement of plasma confinement characteristics obtained by the compound heating of NBI and RF. In this paper, the main results of these heating experiments and their significance are explained. The JT-60 is the testing facilities for attaining the critical plasma condition by additionally heating the plasma which is generated by Joule electric discharge with NBI and RF heatings. The experimental operation cycle of the JT-60 consists of the unit cycle of two weeks, and the number of days in operation is nine days. The temperature of heated plasma rose to 70 million deg C in the 20 MW NBI heating. Hereafter, the improvement of confinement time by increasing the stored energy of plasma is attempted. (Kako, I.)

  11. Safety provision during heating of coal downcast shafts with gas heat generators using degassed methane

    Directory of Open Access Journals (Sweden)

    В. Р. Алабьев

    2017-06-01

    Together with heat generators of mixed type the article also describes a working principle of heat generator of indirect action type, which to the fullest extent possible meets requirements of Russian Federation legislation and regulation for application of this heat generators in coal mines conditions. The article has a principal working scheme of heat unit layout using this type of generator. It is shown that after development of corresponding normative documents regulating processes of design, construction and operation of heating units using heaters of indirect action, their application in Russian coal mines will be possible without breaking Safety standards and rules.

  12. A review of magnetic heat pump technology

    International Nuclear Information System (INIS)

    Barclay, J.A.

    1990-01-01

    The area of technology classified as heat pumps generally refers to refrigerators, heat pumps and heat engines. This review is restricted to the literature on magnetic refrigerators and magnetic heat pumps which are referred to interchangeably. Significant progress has been made on the development of engineering prototypes of cryogenic, nonregenerative magnetic refrigerators utilizing conductive heat transfer in the 0.1 K to 20 K temperature range. Advances have also been made in analysis of regenerative magnetic refrigerators and heat pumps utilizing the active magnetic regeneration (AMR) concept. Units based on AMR are being modeled, designed and/or built to operate in various temperature ranges including 1.8-4.5 K, 4-15 K, 15-85 K, and 270-320 K. The near room temperature units have been scaled to 50 kW as both refrigerators and heat pumps. The progress of magnetic refrigeration over the last three years is summarized and discussed

  13. Monopole heat

    International Nuclear Information System (INIS)

    Turner, M.S.

    1983-01-01

    Upper bounds on the flux of monopoles incident on the Earth with velocity -5 c(10 16 GeV m -1 ) and on the flux of monopoles incident on Jupiter with velocity -3 c(10 16 GeV m -1 ), are derived. Monopoles moving this slowly lose sufficient energy to be stopped, and then catalyse nucleon decay, releasing heat. The limits are obtained by requiring the rate of energy release from nucleon decay to be less than the measured amount of heat flowing out from the surface of the planet. (U.K.)

  14. Heat exchanger

    International Nuclear Information System (INIS)

    Drury, C.R.

    1988-01-01

    A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections

  15. Heat Convection

    Science.gov (United States)

    Jiji, Latif M.

    Professor Jiji's broad teaching experience lead him to select the topics for this book to provide a firm foundation for convection heat transfer with emphasis on fundamentals, physical phenomena, and mathematical modelling of a wide range of engineering applications. Reflecting recent developments, this textbook is the first to include an introduction to the challenging topic of microchannels. The strong pedagogic potential of Heat Convection is enhanced by the follow ing ancillary materials: (1) Power Point lectures, (2) Problem Solutions, (3) Homework Facilitator, and, (4) Summary of Sections and Chapters.

  16. Heat stroke in Hajj ceremonies

    Directory of Open Access Journals (Sweden)

    Sadr Sh

    1995-04-01

    Full Text Available Three hundred and seventy seven patients with different degrees of heat stroke were treated by the haji medical team of the Islamic Republic of Iran in 1371 (1992. Studies were carried out on sex of the patients, time and intensity of occurance and the vital signs after a medical examination. The most important method of treatment employed for intense heat stroke was iced bath. This procedure leads to 64.5% of patients being treated in te specific heat stroke unit and 35% were sent to a general hospital ward for furthur treatment. Morbidity and mortality were seen in less than 0.5% of the patients.

  17. Influence of the heat transfer to the building structures on the confinement parameters in case of a 200 mm LOCA on units 3 and 4 of NPP Kozloduy with reactors WWER-440/V230

    International Nuclear Information System (INIS)

    Stanev, I.

    2001-01-01

    The authors present a general analysis of the mass and energy balance in the WWER-440/V230 confinement structure in case of a 200 mm LOCA, based on results from CONTAIN calculations. The character of the heat transfer to the confinement building structures is analyzed and its influence on the confinement parameters is evaluated. The results show that the building structures heat consumption is comparable to that of the Spray System heat exchanger. (author)

  18. Overall conductance and heat transfer area minimization of refrigerators and heat pumps with finite heat reservoirs

    International Nuclear Information System (INIS)

    Sarkar, J.; Bhattacharyya, Souvik

    2007-01-01

    In the present study, the overall conductance and the overall heat transfer area per unit capacity of refrigeration and heat pump systems have been minimized analytically considering both internal and external irreversibilities with variable temperature (finite capacity) heat reservoirs. Hot and cold side refrigerant temperatures, conductance and heat transfer area ratios have been optimized to attain this goal. The results have been verified with the more elaborate numerical optimization results obtained for ammonia based vapour compression refrigeration and heat pump systems working with variable temperature reservoirs. It is observed that the analytical results for optimum refrigerant temperatures, minimum overall conductance and heat transfer area deviate marginally from the numerically optimized results (within 1%), if one assumes a constant heat rejection temperature. The deviation of minimum overall conductance and heat transfer area is more (about 20%), if one considers both the desuperheating and condensation regions separately. However, in the absence of complex and elaborate numerical models, the simple analytical results obtained here can be used as reasonably accurate preliminary guidelines for optimization of refrigeration and heat pump systems

  19. Renewable Heating And Cooling

    Science.gov (United States)

    Renewable heating and cooling is a set of alternative resources and technologies that can be used in place of conventional heating and cooling technologies for common applications such as water heating, space heating, space cooling and process heat.

  20. Heat exchanger

    Science.gov (United States)

    Wolowodiuk, Walter

    1976-01-06

    A heat exchanger of the straight tube type in which different rates of thermal expansion between the straight tubes and the supply pipes furnishing fluid to those tubes do not result in tube failures. The supply pipes each contain a section which is of helical configuration.

  1. Heat exchangers

    International Nuclear Information System (INIS)

    1975-01-01

    The tubes of a heat exchanger tube bank have a portion thereof formed in the shape of a helix, of effective radius equal to the tube radius and the space between two adjacent tubes, to tangentially contact the straight sections of the tubes immediately adjacent thereto and thereby provide support, maintain the spacing and account for differential thermal expansion thereof

  2. Heat exchanger

    International Nuclear Information System (INIS)

    Wolowodiuk, W.

    1976-01-01

    A heat exchanger of the straight tube type is described in which different rates of thermal expansion between the straight tubes and the supply pipes furnishing fluid to those tubes do not result in tube failures. The supply pipes each contain a section which is of helical configuration

  3. Heat pumps as a way to Low or Zero Emission district heating systems

    Directory of Open Access Journals (Sweden)

    Jadwiszczak Piotr

    2017-01-01

    In traditional district heating (DH system heat is generated from fossil fuel (FF combustion in heating only boilers (HOB or in combined heat and power (CHP plants. It results in greenhouse gases and other pollutants emission. The reduction of emission is one of the main target in EU climate policy. Among the alternative technologies in DH heat pumps (HP play a crucial role and enable to decrease or even eliminate emission to create a low or zero emission (LZE DH system. The emission reduction effect of integration the large scale HP units into DH systems can by defined by four groups of factors: the share of HP in the heat demand, the heat source for HP, the driving energy for HP and heat sink for HP. This paper illustrates the main options for large scale HP units application for LZE DH based on HP technology.

  4. Refrigeration Playbook. Heat Reclaim; Optimizing Heat Rejection and Refrigeration Heat Reclaim for Supermarket Energy Conservation

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Chuck [CTA Architects Engineers, Boise, ID (United States); Nelson, Eric [CTA Architects Engineers, Boise, ID (United States); Armer, James [CTA Architects Engineers, Boise, ID (United States); Johnson, Tim [CTA Architects Engineers, Boise, ID (United States); Hirsch, Adam [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Doebber, Ian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    The purpose of this playbook and accompanying spreadsheets is to generalize the detailed CBP analysis and to put tools in the hands of experienced refrigeration designers to evaluate multiple applications of refrigeration waste heat reclaim across the United States. Supermarkets with large portfolios of similar buildings can use these tools to assess the impact of large-scale implementation of heat reclaim systems. In addition, the playbook provides best practices for implementing heat reclaim systems to achieve the best long-term performance possible. It includes guidance on operations and maintenance as well as measurement and verification.

  5. Model of a thermal energy storage device integrated into a solar assisted heat pump system for space heating

    International Nuclear Information System (INIS)

    Badescu, Viorel

    2003-01-01

    Details about modelling a sensible heat thermal energy storage (TES) device integrated into a space heating system are given. The two main operating modes are described. Solar air heaters provide thermal energy for driving a vapor compression heat pump. The TES unit ensures a more efficient usage of the collected solar energy. The TES operation is modeled by using two non-linear coupled partial differential equations for the temperature of the storage medium and heat transfer fluid, respectively. Preliminary results show that smaller TES units provide a higher heat flux to the heat pump vaporiser. This makes the small TES unit discharge more rapidly during time periods with higher thermal loads. The larger TES units provide heat during longer time periods, even if the heat flux they supply is generally smaller. The maximum heat flux is extracted from the TES unit during the morning. Both the heat pump COP and exergy efficiency decrease when the TES unit length increases. Also, the monthly thermal energy stored by the TES unit and the monthly energy necessary to drive the heat pump compressor are increased by increasing the TES unit length

  6. Heat pipe heat exchangers in heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Stulc, P; Vasiliev, L L; Kiseljev, V G; Matvejev, Ju N

    1985-01-01

    The results of combined research and development activities of the National Research Institute for Machine Design, Prague, C.S.S.R. and the Institute for Heat and Mass Transfer, Minsk, U.S.S.R. concerning intensification heat pipes used in heat pipe heat exchangers are presented. This sort of research has been occasioned by increased interest in heat power economy trying to utilise waste heat produced by various technological processes. The developed heat pipes are deployed in construction of air-air, gas-air or gas-gas heat recovery exchangers in the field of air-engineering and air-conditioning. (author).

  7. Waste Heat to Power Market Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Elson, Amelia [ICF International, Fairfax, VA (United States); Tidball, Rick [ICF International, Fairfax, VA (United States); Hampson, Anne [ICF International, Fairfax, VA (United States)

    2015-03-01

    Waste heat to power (WHP) is the process of capturing heat discarded by an existing process and using that heat to generate electricity. In the industrial sector, waste heat streams are generated by kilns, furnaces, ovens, turbines, engines, and other equipment. In addition to processes at industrial plants, waste heat streams suitable for WHP are generated at field locations, including landfills, compressor stations, and mining sites. Waste heat streams are also produced in the residential and commercial sectors, but compared to industrial sites these waste heat streams typically have lower temperatures and much lower volumetric flow rates. The economic feasibility for WHP declines as the temperature and flow rate decline, and most WHP technologies are therefore applied in industrial markets where waste heat stream characteristics are more favorable. This report provides an assessment of the potential market for WHP in the industrial sector in the United States.

  8. Heat Conduction of Air in Nano Spacing

    Directory of Open Access Journals (Sweden)

    Zhang Yao-Zhong

    2009-01-01

    Full Text Available Abstract The scale effect of heat conduction of air in nano spacing (NS is very important for nanodevices to improve their life and efficiency. By constructing a special technique, the changes of heat conduction of air were studied by means of measuring the heat conduction with heat conduction instrument in NS between the hot plate and the cooling plate. Carbon nanotubes were used to produce the nano spacing. The results show that when the spacing is small down to nanometer scale, heat conduction plays a prominent role in NS. It was found that the thickness of air is a non-linear parameter for demarcating the heat conduction of air in NS and the rate of heat conduction in unit area could be regard as a typical parameter for the heat conduction characterization at nanometer scale.

  9. Heat exchanger

    International Nuclear Information System (INIS)

    Bennett, J.C.

    1975-01-01

    A heat exchanger such as forms, for example, part of a power steam boiler is made up of a number of tubes that may be arranged in many different ways, and it is necessary that the tubes be properly supported. The means by which the tubes are secured must be as simple as possible so as to facilitate construction and must be able to continue to function effectively under the varying operating conditions to which the heat exchanger is subject. The arrangement described is designed to meet these requirements, in an improved way. The tubes are secured to a member extending past several tubes and abutment means are provided. At least some of the abutment means comprise two abutment pieces and a wedge secured to the supporting member, that acts on these pieces to maintain the engagement. (U.K.)

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

    KAUST Repository

    Thu, Kyaw; Kim, Youngdeuk; Myat, Aung; Chakraborty, Anutosh; Ng, K. C.

    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

  11. Distributed heat generation in a district heating system

    OpenAIRE

    Lennermo, Gunnar; Lauenberg, Patrick

    2016-01-01

    District heating (OH) systems need to be improved  regarding integration  of decentralised  heat generation. Micro production, prosumers and smart grids are terms becoming more and more common  in  connection  to  the  power  grid.  Concerning district  heating,  the  development  is slower, although improving. Today there are a number of such decentralised units for heat generation,  mainly  solar,  that have been partly evaluated.  Previous  studies  have shown  that there is a need to deve...

  12. Basic principles of solar water heating

    CSIR Research Space (South Africa)

    Page-Shipp, RJ

    1980-09-10

    Full Text Available This article correctly reflects the principles of Solar Water Heating as they pertain to South African conditions. However, it was written in 1980 and the global energy situation has changed considerably. Furthermore, modern commercial units...

  13. Unregulated heat output of a storage heater

    OpenAIRE

    Lysak, Oleg Віталійович

    2017-01-01

    In the article the factors determining the heat transfer between the outer surfaces of a storage heater and the ambient air. This heat exchange is unregulated, and its definition is a precondition for assessing heat output range of this type of units. It was made the analysis of the literature on choosing insulating materials for each of the external surfaces of storage heaters: in foreign literature, there are recommendations on the use of various types of insulation depending on the type of...

  14. Cooling Acoustic Transcucer with Heat Pipes

    Science.gov (United States)

    2009-07-19

    circuits to a heat sink. [0009] In Kan et al (United States Patent No. 6,528,909), a spindle motor assembly is disclosed which has a shaft with an...integral heat pipe. The shaft with the integral heat pipe improves the thermal conductively of the shaft and the spindle motor assembly. The shaft ...2) Description of the Prior Art [0004] It is known in the art that transducers, designed to project acoustic power, are often limited by the

  15. Cooling Acoustic Transducer with Heat Pipes

    Science.gov (United States)

    2009-07-29

    a heat sink. [0009] In Kan et al (United States Patent No. 6,528,909), a spindle motor assembly is disclosed which has a shaft with an integral...heat pipe. The shaft with the integral heat pipe improves the thermal conductively of the shaft and the spindle motor assembly. The shaft includes...Description of the Prior Art [0004] It is known in the art that transducers, designed to project acoustic power, are often limited by the build

  16. Heating networks and domestic central heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Kamler, W; Wasilewski, W

    1976-08-01

    This is a comprehensive survey of the 26 contributions from 8 European countries submitted to the 3rd International District Heating Conference in Warsaw held on the subject 'Heating Networks and Domestic Central Heating Systems'. The contributions are grouped according to 8 groups of subjects: (1) heat carriers and their parameters; (2) system of heating networks; (3) calculation and optimization of heating networks; (4) construction of heating networks; (5) operation control and automation; (6) operational problems; (7) corrosion problems; and (8) methods of heat accounting.

  17. Hydride heat pump with heat regenerator

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  18. Heating systems for heating subsurface formations

    Science.gov (United States)

    Nguyen, Scott Vinh [Houston, TX; Vinegar, Harold J [Bellaire, TX

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  19. Heat pumps at the maltings

    Energy Technology Data Exchange (ETDEWEB)

    1987-11-01

    Heat pumps have halved the energy costs of producing finished malt at two of the country's maltsters. The fuel-fired kilning processes described are now performed by heat pumps with considerable energy and production benefits at the maltings of J.P. Simpson and Co. (Alnwick) Ltd, in Tivetshall St Margaret, Norfolk, and of Munton and Fison Plc of Stowmarket, Suffolk. The heat pump system installed at the Station Malting of J.P. Simpson was devised by the Electricity Council Research Centre at Capenhurst near Chester. Energy cost benefits of Pound 6,000 a month are being realised at Simpsons, but there is the added benefit that the system has been designed to provide conditioned air to the germination cycle to ensure that the correct temperature is maintained throughout the year. At the Cedars factory of Munton and Fison, heat pumps were used on a trial basis for plant micropropagation and for a fish farming unit.

  20. A modeling approach for district heating systems with focus on transient heat transfer in pipe networks

    DEFF Research Database (Denmark)

    Mohammadi, Soma; Bojesen, Carsten

    2015-01-01

    the temperature in DH systems. The main focus is on modeling transient heat transfer in pipe networks regarding the time delays between the heat supply unit and the consumers, the heat loss in the pipe networks and the consumers’ dynamic heat loads. A pseudo-dynamic approach is adopted and also the implicit...... district heating networks [DHN] characteristics. This paper is presenting a new developed model, which reflects the thermo-dynamic behavior of DHN. It is designed for tree network topologies. The purpose of the model is to serve as a basis for applying a variety of scenarios towards lowering...... finite element method is applied to simulate transient temperature changes in pipe networks. The model is calculating time series data related to supply temperature to the DHN from heat production units, heat loads and return temperature related to each consumer to calculate dynamic temperature changes...

  1. Studies of unavoidable heat production and valorisation in Ile-de-France from non-hazardous waste incineration units (UIDNDs), industries, data centres and waste waters. Local communities - External synthesis phase 1, September 2015 + Synthesis May 2017

    International Nuclear Information System (INIS)

    Florette, Claire; Louillat, Stefan; Lopes, Marie; Jacquemin, L.A.

    2017-09-01

    After a presentation of the study and of its context (more particularly phase I of the study which addresses the identification and characterisation of existing operations and of maximum deposits of unavoidable heat), a first report presents characteristics of industrial non-avoidable heat: deposit description, data collection and deposit assessment methodology, synthesis and deposit map. In the same way, it addresses others deposits: non-hazardous waste incineration plants, data centres, and waste waters. The second report aims at defining a strategy for the recovery of unavoidable heat at a regional scale (Ile-de-France). It focuses on processes for which heat production is not the main purpose. For the same deposits as in the first report, the study aims at identifying and characterizing existing operations and maximum deposits of heat recovery at the regional scale, at assessing and characterizing potential recovery of non avoidable heat while taking technical, legal and economic obstacles into account, and then at defining areas for priority actions

  2. Heat pipes

    CERN Document Server

    Dunn, Peter D

    1982-01-01

    A comprehensive, up-to-date coverage of the theory, design and manufacture of heat pipes and their applications. This latest edition has been thoroughly revised, up-dated and expanded to give an in-depth coverage of the new developments in the field. Significant new material has been added to all the chapters and the applications section has been totally rewritten to ensure that topical and important applications are appropriately emphasised. The bibliography has been considerably enlarged to incorporate much valuable new information. Thus readers of the previous edition, which has established

  3. Heat exchanger

    International Nuclear Information System (INIS)

    Dostatni, A.W.; Dostatni, Michel.

    1976-01-01

    In the main patent, a description was given of a heat exchanger with an exchange surface in preformed sheet metal designed for the high pressure and temperature service particularly encountered in nuclear pressurized water reactors and which is characterised by the fact that it is composed of at least one exchanger bundle sealed in a containment, the said bundle or bundles being composed of numerous juxtaposed individual compartments whose exchange faces are built of preformed sheet metal. The present addendun certificate concerns shapes of bundles and their positioning methods in the exchanger containment enabling its compactness to be increased [fr

  4. Experimental study on heat pipe assisted heat exchanger used for industrial waste heat recovery

    International Nuclear Information System (INIS)

    Ma, Hongting; Yin, Lihui; Shen, Xiaopeng; Lu, Wenqian; Sun, Yuexia; Zhang, Yufeng; Deng, Na

    2016-01-01

    Highlights: • A heat pipe heat exchanger (HPHE) was used to recycle the waste heat in a slag cooling process of steel industry. • An specially designed on-line cleaning device was construed and used to enhance the heat transfer of HPHE. • The performance characteristics of a HPHE has been assessed by integrating the first and second law of thermodynamics. • The optimum operation conditions was determined by integrating the first and the second law of thermodynamics. - Abstract: Steel industry plays an important role economically in China. A great amount of hot waste liquids and gases are discharged into environment during many steelmaking processes. These waste liquids and gases have crucial energy saving potential, especially for steel slag cooling process. It could be possible to provide energy saving by employing a waste heat recovery system (WHRS). The optimum operation condition was assessed by integrating the first and the second law of thermodynamics for a water–water heat pipe heat exchanger (HPHE) for a slag cooling process in steel industry. The performance characteristics of a HPHE has been investigated experimentally by analyzing heat transfer rate, heat transfer coefficient, effectiveness, exergy efficiency and number of heat transfer units (NTU). A specially designed on-line cleaning device was used to clean the heat exchange tubes and enhance heat transfer. The results indicated that the exergy efficiency increased with the increment of waste water mass flow rate at constant fresh water mass flow rate, while the effectiveness decreased at the same operation condition. As the waste water mass flow rate varied from 0.83 m"3/h to 1.87 m"3/h, the effectiveness and exergy efficiency varied from 0.19 to 0.09 and from 34% to 41%, respectively. In the present work, the optimal flow rates of waste water and fresh water were 1.20 m"3/h and 3.00 m"3/h, respectively. The on-line cleaning device had an obvious effect on the heat transfer, by performing

  5. Regenerative Hydride Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    1992-01-01

    Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

  6. Low temperature nuclear heat

    Energy Technology Data Exchange (ETDEWEB)

    Kotakorpi, J.; Tarjanne, R. [comps.

    1977-08-01

    The meeting was concerned with the use of low grade nuclear heat for district heating, desalination, process heat, and agriculture and aquaculture. The sessions covered applications and demand, heat sources, and economics.

  7. Radiofrequency plasma heating: proceedings

    International Nuclear Information System (INIS)

    Swenson, D.G.

    1985-01-01

    The conference proceedings include sessions on Alfven Wave Heating, ICRF Heating and Current Drive, Lower Hybrid Heating and Current Drive, and ECRF Heating. Questions of confinement, diagnostics, instabilities and technology are considered. Individual papers are cataloged separately

  8. Low-Cost Gas Heat Pump for Building Space Heating

    Energy Technology Data Exchange (ETDEWEB)

    Garrabrant, Michael [Stone Mountain Technologies, Inc., Johnson City, TN (United States); Keinath, Christopher [Stone Mountain Technologies, Inc., Johnson City, TN (United States)

    2016-10-11

    Gas-fired residential space heating in the U.S is predominantly supplied by furnaces and boilers. These technologies have been approaching their thermodynamic limit over the past 30 years and improvements for high efficiency units have approached a point of diminishing return. Electric heat pumps are growing in popularity but their heating performance at low ambient temperatures is poor. The development of a low-cost gas absorption heat pump would offer a significant improvement to current furnaces and boilers, and in heating dominated climate zones when compared to electric heat pumps. Gas absorption heat pumps (GAHP) exceed the traditional limit of thermal efficiency encountered by typical furnaces and boilers, and maintain high levels of performance at low ambient temperatures. The project team designed and demonstrated two low-cost packaged prototype GAHP space heating systems during the course of this investigation. Led by Stone Mountain Technologies Inc. (SMTI), with support from A.O. Smith, and the Gas Technology Institute (GTI), the cross-functional team completed research and development tasks including cycle modeling, 8× scaling of a compact solution pump, combustion system development, breadboard evaluation, fabrication of two packaged prototype units, third party testing of the first prototype, and the evaluation of cost and energy savings compared to high and minimum efficiency gas options. Over the course of the project and with the fabrication of two Alpha prototypes it was shown that this technology met or exceeded most of the stated project targets. At ambient temperatures of 47, 35, 17 and -13°F the prototypes achieved gas based coefficients of performance of 1.50, 1.44, 1.37, and 1.17, respectively. Both units operated with parasitic loads well below the 750 watt target with the second Alpha prototype operating 75-100 watts below the first Alpha prototype. Modulation of the units at 4:1 was achieved with the project goal of 2:1 modulation

  9. The optimization of longitudinal convective fins with internal heat generation

    International Nuclear Information System (INIS)

    Razelos, P.

    1979-01-01

    The solution of the optimization problem for longitudinal convective fins of constant thickness, triangular or parabolic profile, and uniform internal heat generation, is presented. The cases considered are those of a given heat generation density, total heat generation and heat generation per unit width of the fin, when either the heat dissipation or the width of the fin is prescribed. The results are set forth in a nondimensional form, which are presented graphically. The effect of the fin's thermal conductivity upon the optimum dimensions is discussed, and limiting values for the heat generation and the heat dissipation, which may be imposed on the fin for a feasible optimization, are also obtained. (Auth.)

  10. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  11. Dual source heat pump

    Science.gov (United States)

    Ecker, Amir L.; Pietsch, Joseph A.

    1982-01-01

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

  12. 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.

  13. Earliest Deadline Control of a Group of Heat Pumps with a Single Energy Source

    NARCIS (Netherlands)

    Fink, J.; van Leeuwen, Richard Pieter

    2016-01-01

    In this paper, we develop and investigate the optimal control of a group of 104 heat pumps and a central Combined Heat and Power unit (CHP). The heat pumps supply space heating and domestic hot water to households. Each house has a buffer for domestic hot water and a floor heating system for space

  14. Reactor waste heat utilization and district heating reactors. Nuclear district heating in Sweden - Regional reject heat utilization schemes and small heat-only reactors

    International Nuclear Information System (INIS)

    Hannerz, K.; Larsson, Y.; Margen, P.

    1977-01-01

    A brief review is given of the current status of district heating in Sweden. In future, district heating schemes will become increasingly interesting as a means of utilizing heat from nuclear reactors. Present recommendations in Sweden are that large reactors should not be located closer than about 20 km from large population centres. Reject heat from such reactors is cheap at source. To minimize the cost of long distance hot water transmission large heat rates must be transmitted. Only areas with large populations can meet this requirement. The three areas of main interest are Malmoe/Lund/Helsingborg housing close to 0.5 million; Greater Stockholm housing 1 to 1.5 million and Greater Gothenburg housing about 0.5 million people. There is an active proposal that the Malmoe/Lund/Helsingborg region would be served by a third nuclear unit at Barsebaeck, located about 20 km from Malmoe/Lund and supplying 950 MW of base load heat. Preliminary proposals for Stockholm involve a 2000 MW heat supply; proposals for Gothenburg are more tentative. The paper describes progress on these proposals and their technology. It also outlines technology under development to increase the economic range of large scale heat transport and to make distribution economic even for low heat-density family housing estates. Regions apart from the few major urban areas mentioned above require the adoption of a different approach. To this end the development of a small, simple low-temperature reactor for heat-only production suitable for urban location has been started in Sweden in close contact with Finland. Some results of the work in progress are presented, with emphasis on the safety requirements. An outline is given in the paper as to how problems of regional heat planning and institutional and legislative issues are being approached

  15. Solar assisted heat pump on air collectors: A simulation tool

    Energy Technology Data Exchange (ETDEWEB)

    Karagiorgas, Michalis; Galatis, Kostas; Tsagouri, Manolis [Department of Mechanical Engineering Educators, ASPETE, N. Iraklio, GR 14121 (Greece); Tsoutsos, Theocharis [Environmental Engineering Dept., Technical University of Crete, Technical University Campus, GR 73100, Chania (Greece); Botzios-Valaskakis, Aristotelis [Centre for Renewable Energy Sources (CRES), 19th km Marathon Ave., GR 19001, Pikermi (Greece)

    2010-01-15

    The heating system of the bioclimatic building of the Greek National Centre for Renewable Energy Sources (CRES) comprises two heating plants: the first one includes an air source heat pump, Solar Air Collectors (SACs) and a heat distribution system (comprising a fan coil unit network); the second one is, mainly, a geothermal heat pump unit to cover the ground floor thermal needs. The SAC configuration as well as the fraction of the building heating load covered by the heating plant are assessed in two operation modes; the direct (hot air from the collectors is supplied directly to the heated space) and the indirect mode (warm air from the SAC or its mixture with ambient air is not supplied directly to the heated space but indirectly into the evaporator of the air source heat pump). The technique of the indirect mode of heating aims at maximizing the efficiency of the SAC, saving electrical power consumed by the compressor of the heat pump, and therefore, at optimizing the coefficient of performance (COP) of the heat pump due to the increased intake of ambient thermal energy by means of the SAC. Results are given for three research objectives: assessment of the heat pump efficiency whether in direct or indirect heating mode; Assessment of the overall heating plant efficiency on a daily or hourly basis; Assessment of the credibility of the suggested simulation model TSAGAIR by comparing its results with the TRNSYS ones. (author)

  16. Heat pipes in modern heat exchangers

    International Nuclear Information System (INIS)

    Vasiliev, Leonard L.

    2005-01-01

    Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 10 3 -10 5 W/m 2 K, heat pipe thermal resistance is 0.01-0.03 K/W, therefore leading to smaller area and mass of heat exchangers. Miniature and micro heat pipes are welcomed for electronic components cooling and space two-phase thermal control systems. Loop heat pipes, pulsating heat pipes and sorption heat pipes are the novelty for modern heat exchangers. Heat pipe air preheaters are used in thermal power plants to preheat the secondary-primary air required for combustion of fuel in the boiler using the energy available in exhaust gases. Heat pipe solar collectors are promising for domestic use. This paper reviews mainly heat pipe developments in the Former Soviet Union Countries. Some new results obtained in USA and Europe are also included

  17. Improving district heating in Kiev

    International Nuclear Information System (INIS)

    Salminen, P.

    2000-01-01

    The district heating modernisation project currently under way in Kiev, the capital of the Ukraine, is the largest project of its type financed by the World Bank. The budget for the five-year project is some USD 250 million of which USD 200 million is financed by the World Bank loan. The target of the project is to improve the city's district heating system, which is owned and operated by Kyivenergo. Consultancy services for the Project Implementation Unit are being provided by Electrowatt-Ekono and financed by the Finnish government

  18. Interface unit

    NARCIS (Netherlands)

    Keyson, D.V.; Freudenthal, A.; De Hoogh, M.P.A.; Dekoven, E.A.M.

    2001-01-01

    The invention relates to an interface unit comprising at least a display unit for communication with a user, which is designed for being coupled with a control unit for at least one or more parameters in a living or working environment, such as the temperature setting in a house, which control unit

  19. Comparison of heat-testing methodology.

    Science.gov (United States)

    Bierma, Mark M; McClanahan, Scott; Baisden, Michael K; Bowles, Walter R

    2012-08-01

    Patients with irreversible pulpitis occasionally present with a chief complaint of sensitivity to heat. To appropriately diagnose the offending tooth, a variety of techniques have been developed to reproduce this chief complaint. Such techniques cause temperature increases that are potentially damaging to the pulp. Newer electronic instruments control the temperature of a heat-testing tip that is placed directly against a tooth. The aim of this study was to determine which method produced the most consistent and safe temperature increase within the pulp. This consistency facilitates the clinician's ability to differentiate between a normal pulp and irreversible pulpitis. Four operators applied the following methods to each of 4 extracted maxillary premolars (for a total of 16 trials per method): heated gutta-percha, heated ball burnisher, hot water, and a System B unit or Elements unit with a heat-testing tip. Each test was performed for 60 seconds, and the temperatures were recorded via a thermocouple in the pulp chamber. Analysis of the data was performed by using the intraclass correlation coefficient. The least consistent warming was found with hot water. The heat-testing tip also demonstrated greater consistency between operators compared with the other methods. Hot water and the heated ball burnisher caused temperature increases high enough to damage pulp tissue. The Elements unit with a heat-testing tip provides the most consistent warming of the dental pulp. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  20. A nuclear reactor for district heating

    International Nuclear Information System (INIS)

    Bancroft, A.R.; Fenton, N.

    1989-07-01

    Global energy requirements are expected to double over the next 40 years. In the northern hemisphere, many countries consume in excess of 25 percent of their primary energy supply for building heating. Satisfying this need, within the constraints now being acknowledged for sustainable global development, provides an important opportunity for district heating. Fuel-use flexibility, energy and resource conservation, and reduced atmospheric pollution from acid gases and greenhouse gases, are important features offered by district heating systems. Among the major fuel options, only hydro-electricity and nuclear heat completely avoid emissions of combustion gases. To fill the need for an economical nuclear heat source, Atomic Energy of Canada Limited has designed a 10 MW plant that is suitable as a heat source within a network or as the main supply to large individual users. Producing hot water at temperatures below 100 degrees C, it incorporates a small pool-type reactor based on AECL's successful SLOWPOKE Research Reactor. A 2 MW prototype for the commercial unit is now being tested at the Whiteshell Nuclear Research Establishment in Manitoba. With capital costs of $7 million (Canadian), unit energy costs are projected to be $0.02/kWh for a 10 MW unit operating in a heating grid over a 30-year period. By keeping the reactor power low and the water temperature below 100 degrees C, much of the complexity of the large nuclear power plants can be avoided, thus allowing these small, safe nuclear heating systems to be economically viable

  1. Heat transfer analysis of underground U-type heat exchanger of ground source heat pump system.

    Science.gov (United States)

    Pei, Guihong; Zhang, Liyin

    2016-01-01

    Ground source heat pumps is a building energy conservation technique. The underground buried pipe heat exchanging system of a ground source heat pump (GSHP) is the basis for the normal operation of an entire heat pump system. Computational-fluid-dynamics (CFD) numerical simulation software, ANSYS-FLUENT17.0 have been performed the calculations under the working conditions of a continuous and intermittent operation over 7 days on a GSHP with a single-well, single-U and double-U heat exchanger and the impact of single-U and double-U buried heat pipes on the surrounding rock-soil temperature field and the impact of intermittent operation and continuous operation on the outlet water temperature. The influence on the rock-soil temperature is approximately 13 % higher for the double-U heat exchanger than that of the single-U heat exchanger. The extracted energy of the intermittent operation is 36.44 kw·h higher than that of the continuous mode, although the running time is lower than that of continuous mode, over the course of 7 days. The thermal interference loss and quantity of heat exchanged for unit well depths at steady-state condition of 2.5 De, 3 De, 4 De, 4.5 De, 5 De, 5.5 De and 6 De of sidetube spacing are detailed in this work. The simulation results of seven working conditions are compared. It is recommended that the side-tube spacing of double-U underground pipes shall be greater than or equal to five times of outer diameter (borehole diameter: 180 mm).

  2. Heat pipe heat exchanger for heat recovery in air conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Baky, Mostafa A.; Mohamed, Mousa M. [Mechanical Power Engineering Department, Faculty of Engineering, Minufiya University, Shebin El-Kom (Egypt)

    2007-03-15

    The heat pipe heat exchangers are used in heat recovery applications to cool the incoming fresh air in air conditioning applications. Two streams of fresh and return air have been connected with heat pipe heat exchanger to investigate the thermal performance and effectiveness of heat recovery system. Ratios of mass flow rate between return and fresh air of 1, 1.5 and 2.3 have been adapted to validate the heat transfer and the temperature change of fresh air. Fresh air inlet temperature of 32-40{sup o}C has been controlled, while the inlet return air temperature is kept constant at about 26{sup o}C. The results showed that the temperature changes of fresh and return air are increased with the increase of inlet temperature of fresh air. The effectiveness and heat transfer for both evaporator and condenser sections are also increased to about 48%, when the inlet fresh air temperature is increased to 40{sup o}C. The effect of mass flow rate ratio on effectiveness is positive for evaporator side and negative for condenser side. The enthalpy ratio between the heat recovery and conventional air mixing is increased to about 85% with increasing fresh air inlet temperature. The optimum effectiveness of heat pipe heat exchanger is estimated and compared with the present experimental data. The results showed that the effectiveness is close to the optimum effectiveness at fresh air inlet temperature near the fluid operating temperature of heat pipes. (author)

  3. Nonazeotropic Heat Pump

    Science.gov (United States)

    Ealker, David H.; Deming, Glenn

    1991-01-01

    Heat pump collects heat from water circulating in heat-rejection loop, raises temperature of collected heat, and transfers collected heat to water in separate pipe. Includes sealed motor/compressor with cooling coils, evaporator, and condenser, all mounted in outer housing. Gradients of temperature in evaporator and condenser increase heat-transfer efficiency of vapor-compression cycle. Intended to recover relatively-low-temperature waste heat and use it to make hot water.

  4. Heat transfer: Pittsburgh 1987

    International Nuclear Information System (INIS)

    Lyczkowski, R.W.

    1987-01-01

    This book contains papers divided among the following sections: Process Heat Transfer; Thermal Hydraulics and Phase Change Phenomena; Analysis of Multicomponent Multiphase Flow and Heat Transfer; Heat Transfer in Advanced Reactors; General Heat Transfer in Solar Energy; Numerical Simulation of Multiphase Flow and Heat Transfer; High Temperature Heat Transfer; Heat Transfer Aspects of Severe Reactor Accidents; Hazardous Waste On-Site Disposal; and General Papers

  5. Implementation of the project for the construction and operation of a nuclear heat and power plant on the basis of a floating power unit with KLT-40C reactors

    Energy Technology Data Exchange (ETDEWEB)

    Polushkin, A K; Kuzin, E A [JSC Malaya Energetika, Moscow (Russian Federation); Vorobiov, V M [JSC Atomenergo, St. Petersburg (Russian Federation); Klykov, D M [JSC Iceberg, St. Petersburg (Russian Federation); Panov, J K [OKBM, Nizhny Novgorod (Russian Federation)

    2000-09-01

    This paper presents the results of research and development on floating nuclear power plant (FNPP) for electricity and heat production for remote locations and small island or coastal communities. Evaluations of construction period, social and economic factors as well as safety and operational issues of the non-self-propelled barge-mounted NPP is given. (author)

  6. Implementation of the project for the construction and operation of a nuclear heat and power plant on the basis of a floating power unit with KLT-40C reactors

    International Nuclear Information System (INIS)

    Polushkin, A.K.; Kuzin, E.A.; Vorobiov, V.M.; Klykov, D.M.; Panov, J.K.

    2000-01-01

    This paper presents the results of research and development on floating nuclear power plant (FNPP) for electricity and heat production for remote locations and small island or coastal communities. Evaluations of construction period, social and economic factors as well as safety and operational issues of the non-self-propelled barge-mounted NPP is given. (author)

  7. Research Proposal for the Design and Engineering Phase of a Solar Heating and Cooling System Experiment at the Warner Robins Public Library, Warner Robins, Georgia. Submitted to the United States Energy Research and Development Administration.

    Science.gov (United States)

    Phillips, Warren H.; And Others

    A number of reasons are advanced to include a solar heating and cooling experiment in a library building. The unique aspects of the experiment are to be a seasonally adjustable collector tilt and testing of a new generation of absorption air conditioners. After a brief description of the proposed experiment, the proposal contains forms filed by…

  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...... 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......-energy house in Sisimiut, which is capable of continuously defrosting itself. The disadvantage of the unit is that it is quite big compared with other units. In this paper the new heat recovery unit is described and laboratory measurements are presented showing that the unit is capable of continuously...

  9. Industrial waste heat for district heating

    International Nuclear Information System (INIS)

    Heitner, K.L.; Brooks, P.P.

    1982-01-01

    Presents 2 bounding evaluations of industrial waste heat availability. Surveys waste heat from 29 major industry groups at the 2-digit level in Standard Industrial Codes (SIC). Explains that waste heat availability in each industry was related to regional product sales, in order to estimate regional waste heat availability. Evaluates 4 selected industries at the 4-digit SIC level. Finds that industrial waste heat represents a significant energy resource in several urban areas, including Chicago and Los Angeles, where it could supply all of these areas residential heating and cooling load. Points out that there is a strong need to evaluate the available waste heat for more industries at the 4-digit level. Urges further studies to identify other useful industrial waste heat sources as well as potential waste heat users

  10. 基于太阳能光伏光热组件的双热源热泵机组的实验研究%Experimental Research of Dual-source Heat Pump Unit Based on Solar Photovoltaic and Photothermal Component

    Institute of Scientific and Technical Information of China (English)

    陈剑波; 孙坤; 聂琳杰; 陈雷田

    2015-01-01

    本文基于太阳能光伏光热一体化系统,设计出应用太阳能光伏光热及空气源的双热源热泵机组。使热泵与太阳能光伏光热组件结合组成太阳能热泵系统,利用太阳能光伏光热组件( PV/T)内循环水及空气源的能量制取生活热水,同时降低太阳能光伏光热组件内循环水的温度,从而降低太阳能光伏板的温度。通过实验测得机组在水冷蒸发侧进水温度20℃,热水出水温度50℃的额定工况下,制冷量为2.855 kW,制热量为3.594 kW,COP为3.6。机组在水-水工况及水-风工况下运行的节能性研究结果表明,相对于单一空气源热泵,双热源热泵机组在满足家庭用生活热水需求的前提下,利用热泵技术回收太阳能光伏光热的热量制取生活热水节能性显著。%Based on the solar photovoltaic-thermal integrated system, we designed a dual-source, i. e. , solar photovoltaic-thermal and air source, heat pump unit. The unit becomes solar assisted heat pump system when combined with solar photovoltaic thermal unit, which produces domestic hot water by air source and circulating water in the solar photovoltaic solar-thermal components ( PV/T) and reduces circulating water temperature and solar photovoltaic panel temperature. We drew the conclusion by experiment that when the inflow water temperature is 20 ℃ on the evaporation side and the outflow hot water temperature is 50 ℃ under the rated conditions, the unit capacity is 2. 855 kW for refrigeration and 3. 594 kW for heating, and the COP is 3. 6. When the unit operates in the water-water condition and wa-ter-air condition, the experiment result shows the dual-source heat pump unit has remarkable energy-saving compared with single air source heat pump when the photovoltaic-thermal solar heat is used for domestic hot water.

  11. Novel Natural Convection Heat Sink Design Concepts From First Principles

    Science.gov (United States)

    2016-06-01

    CONVECTION HEAT SINK DESIGN CONCEPTS FROM FIRST PRINCIPLES by Derek E. Fletcher June 2016 Thesis Advisor: Garth Hobson Second Reader...COVERED Master’s Thesis 4. TITLE AND SUBTITLE NOVEL NATURAL CONVECTION HEAT SINK DESIGN CONCEPTS FROM FIRST PRINCIPLES 5. FUNDING NUMBERS 6...CONVECTION HEAT SINK DESIGN CONCEPTS FROM FIRST PRINCIPLES Derek E. Fletcher Lieutenant Commander, United States Navy B.S., Southwestern

  12. Heat transfer enhancement with condensation by surface rotation

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, L L; Khrolenok, V V [A.V. Luikov Heat and Mass Transfer Inst., Minsk (Belarus)

    1993-11-01

    Process intensification relies on many unit operations on enhanced heat transfer. One technique for the enhancement of condensation heat transfer is the use of surface rotation. This is particularly effective in reducing the condensate film thickness. The formulae and relationships given in this paper are concerned with rotating discs and tubes, and can be used for developing advanced heat exchanger concepts. (Author)

  13. Heat pumps in field test; Waermepumpen im Feldtest

    Energy Technology Data Exchange (ETDEWEB)

    Becker, R. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany); Miara, M.; Russ, C.

    2007-09-15

    The Fraunhofer ISE has launched two field tests of newly installed heat pumps in 2006. Both deal with the measurement of a high number of heat pump units under real conditions in small houses. Values of volume flows, temperatures, heat quantity and electricity consumption are collected and daily saved and analysed at the Fraunhofer ISE. (orig.)

  14. Efficacy of heat treatment for disinfestation of concrete grain silos

    Science.gov (United States)

    Field experiments were conducted in 2007 and 2008 to evaluate heat treatment for disinfestations of empty concrete elevator silos. A Mobile Heat Treatment Unit was used to introduce heat into silos to attain target conditions of 50°C for at least 6 h. Ventilated plastic containers with a capacity of...

  15. Sensors for Metering Heat Flux Area Density and Metrological Equipment for the Heat Flux Density Measurement

    Science.gov (United States)

    Doronin, D. O.

    2018-04-01

    The demand in measuring and studies of heat conduction of various media is very urgent now. This article considers the problem of heat conduction monitoring and measurement in various media and materials in any industries and branches of science as well as metrological support of the heat flux measurement equipment. The main study objects are both the sensors manufactured and facilities onto which these sensors will be installed: different cladding structures of the buildings, awnings, rocket fairings, boiler units, internal combustion engines. The Company develops and manufactures different types of heat flux sensors: thermocouple, thin-film, heterogeneous gradient as well as metrological equipment for the gauging calibration of the heat flux density measurement. The calibration shall be performed using both referencing method in the unit and by fixed setting of the heat flux in the unit. To manufacture heterogeneous heat flux gradient sensors (HHFGS) the Company developed and designed a number of units: diffusion welding unit, HHFGS cutting unit. Rather good quality HHFGS prototypes were obtained. At this stage the factory tests on the equipment for the heat flux density measurement equipment are planned. A high-sensitivity heat flux sensor was produced, now it is tested at the Construction Physics Research Institute (Moscow). It became possible to create thin-film heat flux sensors with the sensitivity not worse than that of the sensors manufactured by Captec Company (France). The Company has sufficient premises to supply the market with a wide range of sensors, to master new sensor manufacture technologies which will enable their application range.

  16. Heat Energy Markets: Trends of Spatial Organization

    Directory of Open Access Journals (Sweden)

    Olga Valeryevna Dyomina

    2016-12-01

    Full Text Available The author reviews competing forms of heat supply. It is shown that in Finland, Denmark, China and Russia the dominant form of heat supply is district heating system; in the United States and Canada the dominant form of heat supply is individual one. Using the countries’ data the author allocates 4 models of heat energy markets. The analysis is based on combinations of the following characteristics: the type of market, the orientation of market, the stage of market development, forms of state support of district heating systems and the approach to pricing. The results identified the failure of the current model of heat energy market in Russia (noncompetitive, manufacturer-oriented and evolved market with massive state support of its district heating system. The ‘target’ model of heat energy market in Russia is a model of noncompetitive, customer-oriented and evolved market with no state support of its district heating system. However, the ‘target’ model takes into account spatial heterogeneity of local heat energy markets in Russia only technically

  17. Investigation and optimization of the depth of flue gas heat recovery in surface heat exchangers

    Science.gov (United States)

    Bespalov, V. V.; Bespalov, V. I.; Melnikov, D. V.

    2017-09-01

    Economic issues associated with designing deep flue gas heat recovery units for natural gas-fired boilers are examined. The governing parameter affecting the performance and cost of surface-type condensing heat recovery heat exchangers is the heat transfer surface area. When firing natural gas, the heat recovery depth depends on the flue gas temperature at the condenser outlet and determines the amount of condensed water vapor. The effect of the outlet flue gas temperature in a heat recovery heat exchanger on the additionally recovered heat power is studied. A correlation has been derived enabling one to determine the best heat recovery depth (or the final cooling temperature) maximizing the anticipated reduced annual profit of a power enterprise from implementation of energy-saving measures. Results of optimization are presented for a surface-type condensing gas-air plate heat recovery heat exchanger for the climatic conditions and the economic situation in Tomsk. The predictions demonstrate that it is economically feasible to design similar heat recovery heat exchangers for a flue gas outlet temperature of 10°C. In this case, the payback period for the investment in the heat recovery heat exchanger will be 1.5 years. The effect of various factors on the optimal outlet flue gas temperature was analyzed. Most climatic, economical, or technological factors have a minor effect on the best outlet temperature, which remains between 5 and 20°C when varying the affecting factors. The derived correlation enables us to preliminary estimate the outlet (final) flue gas temperature that should be used in designing the heat transfer surface of a heat recovery heat exchanger for a gas-fired boiler as applied to the specific climatic conditions.

  18. Low Temperature Heating and High Temperature Cooling in Buildings

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk

    A heating and cooling system could be divided into three parts: terminal units (emission system), distribution system, and heating and cooling plant (generation system). The choice of terminal unit directly affects the energy performance, and the indoor environment in that space. Therefore, a hol...

  19. Automation of heating system with heat pump

    OpenAIRE

    Ferdin, Gašper

    2016-01-01

    Because of high prices of energy, we are upgrading our heating systems with newer, more fuel efficient heating devices. Each new device has its own control system, which operates independently from other devices in a heating system. With a relatively low investment costs in automation, we can group devices in one central control system and increase the energy efficiency of a heating system. In this project, we show how to connect an oil furnace, a sanitary heat pump, solar panels and a heat p...

  20. Heat exchanger with dirt separator for the use of the heat energy of waste water

    Energy Technology Data Exchange (ETDEWEB)

    1975-11-13

    Well-known heat exchanger systems consist of separate heat exchangers and dirt separators. In the case here in question both devices form a unit. A finned tube heat exchanger is positioned in the center of the dirt separator and is given extra protection through deflection sheets. A safety overflow is supplied so that no residue can appear in the waste water line when decanting.

  1. Intermittent heating of buildings

    Energy Technology Data Exchange (ETDEWEB)

    Kohonen, K

    1983-02-01

    Conditions for intermittent heating of buildings are considered both theoretically and experimentally. Thermal behaviour of buildings adn rooms in intermittent heating is simulated by a program based on the convective heat balance equation and by simplified RC-models. The preheat times and the heating energy savings compared with continuous heating are presented for typical lightweight, mediumweight and heavyweight classroom and office modules. Formulaes for estimating the oversizing of the radiator network, the maximum heat output of heat exchangers in district heating and the efficiency of heating boilers in intermittent heating are presented. The preheat times and heating energy savings with different heating control systems are determined also experimentally in eight existing buildings. In addition some principles for the planning and application of intermittent heating systems are suggested.

  2. Heat pump technology

    CERN Document Server

    Von Cube, Hans Ludwig; Goodall, E G A

    2013-01-01

    Heat Pump Technology discusses the history, underlying concepts, usage, and advancements in the use of heat pumps. The book covers topics such as the applications and types of heat pumps; thermodynamic principles involved in heat pumps such as internal energy, enthalpy, and exergy; and natural heat sources and energy storage. Also discussed are topics such as the importance of the heat pump in the energy industry; heat pump designs and systems; the development of heat pumps over time; and examples of practical everyday uses of heat pumps. The text is recommended for those who would like to kno

  3. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  4. Future heat supply of our cities. Heating by waste heat

    Energy Technology Data Exchange (ETDEWEB)

    Brachetti, H E [Stadtwerke Hannover A.G. (Germany, F.R.); Technische Univ. Hannover (Germany, F.R.))

    1976-08-01

    The energy-price crisis resulted in structural changes of the complete energy supply and reactivated the question of energy management with respect to the optimum solution of meeting the energy requirements for space heating. Condensation power plants are increasingly replaced by thermal stations, the waste heat of which is used as so-called district heat. Thermal power stations must be situated close to urban areas. The problem of emission of harmful materials can partly be overcome by high-level emission. The main subject of the article, however, is the problem of conducting and distributing the heat. The building costs of heat pipeline systems and the requirements to be met by heat pipelines such as strength, heat insulation and protection against humidity and ground water are investigated.

  5. Heat tracer methods

    Science.gov (United States)

    Healy, Richard W.; Scanlon, Bridget R.

    2010-01-01

    The flow of heat in the subsurface is closely linked to the movement of water (Ingebritsen et al., 2006). As such, heat has been used as a tracer in groundwater studies for more than 100 years (Anderson, 2005). As with chemical and isotopic tracers (Chapter 7), spatial or temporal trends in surface and subsurface temperatures can be used to infer rates of water movement. Temperature can be measured accurately, economically, at high frequencies, and without the need to obtain water samples, facts that make heat an attractive tracer. Temperature measurements made over space and time can be used to infer rates of recharge from a stream or other surface water body (Lapham, 1989; Stonestrom and Constantz, 2003); measurements can also be used to estimate rates of steady drainage through depth intervals within thick unsaturated zones (Constantz et al., 2003; Shan and Bodvarsson, 2004). Several thorough reviews of heat as a tracer in hydrologic studies have recently been published (Constantz et al., 2003; Stonestrom and Constantz, 2003; Anderson, 2005; Blasch et al., 2007; Constantz et al., 2008). This chapter summarizes heat-tracer approaches that have been used to estimate recharge.Some clarification in terminology is presented here to avoid confusion in descriptions of the various approaches that follow. Diffuse recharge is that which occurs more or less uniformly across large areas in response to precipitation, infiltration, and drainage through the unsaturated zone. Estimates of diffuse recharge determined using measured temperatures in the unsaturated zone are referred to as potential recharge because it is possible that not all of the water moving through the unsaturated zone will recharge the aquifer; some may be lost to the atmosphere by evaporation or plant transpiration. Estimated fluxes across confining units in the saturated zone are referred to as interaquifer flow (Chapter 1). Focused recharge is that which occurs directly from a point or line source, such

  6. Heat-Related Illnesses

    Science.gov (United States)

    ... Share this! EmergencyCareForYou » Emergency 101 » Heat-Related Illnesses Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  7. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Share this! EmergencyCareForYou » Emergency 101 » Heat-Related Illnesses Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  8. Scheduling of radio-controlled heating load

    International Nuclear Information System (INIS)

    Fox, B.; McCartney, A.I.; McCann, B.M.

    1998-01-01

    An economic loading program has been adapted to enable it to obtain an optimum heat-load profile to meet the forecast heat requirement. The heat load is represented by a 'generator' whose load is constrained to be negative. The incremental cost of this unit is a heat energy price. This is adjusted to obtain a heat profile containing the requisite energy. The profile is then used by a dynamic programming algorithm to derive a commitment pattern for each block. A case study is presented which shows that the procedure can minimise heat energy cost. It is also shown that use of the proposed method results in less generator load cycling. This reduced regulation duty should improve reliability. (author)

  9. Incidental electric heating of pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Sonninskii, A V; Sirotin, A M; Vasiliev, Y N

    1981-04-01

    VNIIgaz has improved the conventional Japanese SECT pipeline-heating system, which uses a small steel tube that contains an insulated heater/conductor and is welded to the top of the pipeline. The improved version has two insulated electric heaters - one on the top and the other on the bottom of the pipeline - located inside steel angle irons that are welded to the pipeline. A comparison of experimental results from heating a 200-ft pipeline with both systems at currents of up to 470 A clearly demonstrated the better heating efficiency of the VNIIgaz unit. The improved SECT system would be suitable for various types of pipelines, including gas lines, in the USSR's far north regions.

  10. Heat Pumps in CHP Systems

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt

    that three configurations are particular advantageous, whereas the two remaining configurations result in system performance close to or below what may be expected from an electric heater. One of the three advantageous configurations is required to be positioned at the location of the heat demand, whereas...... the two remaining can be located at positions with availability of high temperature sources by utilising the DH network to distribute the heat. A large amount of operational and economic constraints limit the applicability of HPs operated with natural working fluids, which may be the only feasible choice...... representation allows infeasible production. Using MIP or NLP optimisation, the number of operation hours and the total production of heat from HPs are significantly increased, as the HPs may be used to shave the load patterns of CHP units in significantly constrained energy systems. A MIP energy system model...

  11. Market Potential for Residential Biomass Heating Equipment: Stochastic and Econometric Assessments

    OpenAIRE

    Adee Athiyaman

    2015-01-01

    This paper provides estimates of market potential for biomass-residential-heating equipment in the US: that is, the greatest amount of biomass-residential-heating equipment that can be sold by the industry. The author's analysis is limited to biomass equipment used most to heat the housing unit. Assuming that households equipped with 10+ year old primary heating devices will replace rather than repair the devices he predicts that approximately 1.4 million units of residential home heating equ...

  12. Absorption heat pump system

    Science.gov (United States)

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  13. Heat Related Illnesses

    National Research Council Canada - National Science Library

    Carter, R; Cheuvront, S. N; Sawka, M. N

    2006-01-01

    .... The risk of serious heat illness can be markedly reduced by implementing a variety of countermeasures, including becoming acclimated to the heat, managing heat stress exposure, and maintaining hydration...

  14. Heat Roadmap Europe 1

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg

    2012-01-01

    Heat Roadmap Europe (Pre-study 1) investigates the role of district heating in the EU27 energy system by mapping local conditions across Europe, identifying the potential for district heating expansion, and subsequently simulating the potential resource in an hourly model of the EU27 energy system....... In 2010, approximately 12% of the space heating demand in Europe is met by district heating, but in this study four alternative scenarios are considered for the EU27 energy system: 1. 2010 with 30% district heating 2. 2010 with 50% district heating 3. 2030 with 30% district heating 4. 2050 with 50......% district heating These scenarios are investigated in two steps. Firstly, district heating replaces individual boilers by converting condensing power plants to combined heat and power plants (CHP) to illustrate how district heating improves the overall efficiency of the energy system. In the second step...

  15. Multidimensional Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of multidimensional heat conduction. General heat conduction equation in three dimensions. Steay state, analytical solutions. The Laplace equation. Method of separation of variables. Principle of superposition. Shape factors. Transient, multidimensional heat conduction....

  16. Oscillating heat pipes

    CERN Document Server

    Ma, Hongbin

    2015-01-01

    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  17. Heating in toroidal plasmas

    International Nuclear Information System (INIS)

    Knoepfel, H.; Mazzitelli, G.

    1984-01-01

    The article is a rather detailed report on the highlights in the area of the ''Heating in toroidal plasmas'', as derived from the presentations and discussions at the international symposium with the same name, held in Rome, March 1984. The symposium covered both the physics (experiments and theory) and technology of toroidal fusion plasma heating. Both large fusion devices (either already in operation or near completion) requiring auxiliary heating systems at the level of tens of megawatts, as well as physics of their heating processes and their induced side effects (as studied on smaller devices), received attention. Substantial progress was reported on the broad front of auxiliary plasma heating and Ohmic heating. The presentation of the main conclusions of the symposium is divided under the following topics: neutral-beam heating, Alfven wave heating, ion cyclotron heating, lower hybrid heating, RF current drive, electron cyclotron heating, Ohmic heating and special contributions

  18. Low resource ventilation unit; Ressourcebesparende ventilationsenhed

    Energy Technology Data Exchange (ETDEWEB)

    Drivsholm, C.

    2012-03-15

    In the project a resource-saving ventilation device was developed which is based on the use of a regenerator and a reversible air flow. The regenerator is placed in the building envelope, and the concept works in the way that the heat in the air during ventilation is stored in the regenerator and brought back into the building by a reversible air change. The heated air is blown from inside the building out through the regenerator. In this way the regenerator accumulates the heat in the air. Over a period of 30-120 seconds, the regenerator capacity is utilized. When the regenerator cannot be further heated, the air flow is reversed and there is now blown cold air through the regenerator. Thereby the heat from the regenerator is released to the cold fresh air. Thus, the fresh air brings heat back into the building, whereby the air is replaced with a limited heat loss. Ventilation with a regenerator is described as micro-ventilation. The developed micro-ventilation unit was tested by the Danish Technological Institute. The test results shows that the unit performs according to expectations: 1) The heat recovery is 85%; 2) The flow through the unit is 80m3 per hour in a 5 section unit; 3) The noise level is 30 db(A) in a representative room; 4) The energy consumption is <300 J/m3. The unit is introduced into the market, and the first plants have been sold. (LN)

  19. Heat transfer pipe shielding device for heat exchanger

    International Nuclear Information System (INIS)

    Hanawa, Jun.

    1991-01-01

    The front face and the rear face of a frame that surrounds the circumference of the water chamber body of a multi-tube heat exchanger are covered by a rotational shielding plate. A slit is radially formed to the shielding plate for the insertion of a probe or cleaner to the heat transfer pipe and a deflector is disposed on the side opposite to the slit. The end of the heat transfer pipe to be inspected is exposed to the outer side by way of the slit by the rotation of the shielding plate, and the probe or cleaner is inserted in the heat transfer pipe to conduct an eddy current injury monitoring test or cleaning. The inside of the water chamber and the heat transfer pipe is exhausted by a ventilation nozzle disposed to the frame. Accordingly, a shielding effect upon inspection and cleaning can be obtained and, in addition, inspection and exhaustion at the cleaning position can be conducted easily. Since the operation for attachment and detachment is easy, the effect of reducing radiation dose per unit can be obtained by the shortening of the operation time. (N.H.)

  20. Practical model for economic optimization of a heat recovery plate heat exchanger and its examination

    Energy Technology Data Exchange (ETDEWEB)

    Lepach, T.; Marttila, E.; Hammo, S.

    1997-12-31

    This report presents a practical model for designers whose job it is to dimension a plate heat exchanger used especially in heat recovery systems for ventilation. Special attention was given to the economic optimization of such a unit. The first part of the report presents the most important types of heat exchangers and then goes on to present those that are normally used in ventilation systems for heat recovery. The second part discusses the operating costs, investments required and the savings in costs that can be achieved through heat recovery. The third part takes a look at the theory of heat transfer and the characteristics of heat exchanger. In the finally part, a utilization of this model is presented. The results from this are discussed in the following. The developed equations have been calculated and plotted by the use of the numeric software MATLAB. The code used for calculation with MATLAB is listed in the appendix. (orig.) 16 refs.

  1. Development of a gas fired Vuilleumier heat pump for residential heating

    DEFF Research Database (Denmark)

    Carlsen, Henrik

    1989-01-01

    A natural gas-driven heat pump based on the Vuilleumier principle has been developed for use in single-family houses. The pump has a heat output of 7.5 kW at a coefficient of performance of 1.62 based on the lower heat content of the gas fuel. The heat pump uses helium as working fluid at 20 MPa...... mean pressure, and it is designed as a semihermetic unit. A crank mechanism distinguished by very small loads on the piston rings was developed. The advantages and disadvantages of the Vuilleumier principle for heat-driven heat pumps are discussed. Results of the extensive experimental work...... are presented. A new 20 kW Vuilleumier heat pump is briefly described...

  2. Vapor Compression and Thermoelectric Heat Pump Heat Exchangers for a Condensate Distillation System: Design and Experiment

    Science.gov (United States)

    Erickson, Lisa R.; Ungar, Eugene K.

    2013-01-01

    Maximizing the reuse of wastewater while minimizing the use of consumables is critical in long duration space exploration. One of the more promising methods of reclaiming urine is the distillation/condensation process used in the cascade distillation system (CDS). This system accepts a mixture of urine and toxic stabilizing agents, heats it to vaporize the water and condenses and cools the resulting water vapor. The CDS wastewater flow requires heating and its condensate flow requires cooling. Performing the heating and cooling processes separately requires two separate units, each of which would require large amounts of electrical power. By heating the wastewater and cooling the condensate in a single heat pump unit, mass, volume, and power efficiencies can be obtained. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump performance tests are provided. A summary is provided of the heat pump mass, volume and power trades and a selection recommendation is made.

  3. Development and application of soil coupled heat pump

    Science.gov (United States)

    Liu, Lu

    2017-05-01

    Soil coupled heat pump technology is a new clean heating mode, is the world's most energy efficient heating one of the ways. And because of the use of renewable geothermal resources with high heating performance so more and more people's attention. Although the use of soil-coupled heat pumps has been in use for more than 50 years (the first application in the United States), the market penetration of this technology is still in its infancy. This paper will focus on the development, characteristics and application of the coupled heat pump.

  4. Heat exposure and socio-economic vulnerability as synergistic factors in heat-wave-related mortality

    International Nuclear Information System (INIS)

    Rey, Gregoire; Fouillet, Anne; Bessemoulin, Pierre; Frayssinet, Philippe; Dufour, Anne; Jougla, Eric; Hemon, Denis

    2009-01-01

    Heat waves may become a serious threat to the health and safety of people who currently live in temperate climates. It was therefore of interest to investigate whether more deprived populations are more vulnerable to heat waves. In order to address the question on a fine geographical scale, the spatial heterogeneity of the excess mortality in France associated with the European heat wave of August 2003 was analysed. A deprivation index and a heat exposure index were used jointly to describe the heterogeneity on the Canton scale (3,706 spatial units). During the heat wave period, the heat exposure index explained 68% of the extra-Poisson spatial variability of the heat wave mortality ratios. The heat exposure index was greater in the most urbanized areas. For the three upper quintiles of heat exposure in the densely populated Paris area, excess mortality rates were twofold higher in the most deprived Cantons (about 20 excess deaths/100,000 people/day) than in the least deprived Cantons (about 10 excess deaths/100,000 people/day). No such interaction was observed for the rest of France, which was less exposed to heat and less heterogeneous in terms of deprivation. Although a marked increase in mortality was associated with heat wave exposure for all degrees of deprivation, deprivation appears to be a vulnerability factor with respect to heat-wave-associated mortality.

  5. Regenerative adsorbent heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative adsorbent heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system and at least a portion of the heat of adsorption. A series of at least four compressors containing an adsorbent is provided. A large amount of heat is transferred from compressor to compressor so that heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  6. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    David, Andrei; Mathiesen, Brian Vad; Averfalk, Helge

    2017-01-01

    The Heat Roadmap Europe (HRE) studies estimated a potential increase of the district heating (DH) share to 50% of the entire heat demand by 2050, with approximately 25–30% of it being supplied using large-scale electric heat pumps. This study builds on this potential and aims to document that suc......The Heat Roadmap Europe (HRE) studies estimated a potential increase of the district heating (DH) share to 50% of the entire heat demand by 2050, with approximately 25–30% of it being supplied using large-scale electric heat pumps. This study builds on this potential and aims to document...

  7. Heat pumps in district heating networks

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

    constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... and strategic planning in the energy sector. The paper presents a case study of optimal implementation of heat pumps in the present energy system of the Copenhagen area. By introduction of the correct capacity of heat pumps, a 1,6 % reduction in fuel consumption for electricity and heat production can...

  8. SECURE nuclear district heating plant

    International Nuclear Information System (INIS)

    Nilsson; Hannus, M.

    1978-01-01

    The role foreseen for the SECURE (Safe Environmentally Clean Urban REactor) nuclear district heating plant is to provide the baseload heating needs of primarily the larger and medium size urban centers that are outside the range of waste heat supply from conventional nuclear power stations. The rationale of the SECURE concept is that the simplicity in design and the inherent safety advantages due to the use of low temperatures and pressures should make such reactors economically feasible in much smaller unit sizes than nuclear power reactors and should make their urban location possible. It is felt that the present design should be safe enough to make urban underground location possible without restriction according to any criteria based on actual risk evaluation. From the environmental point of view, this is a municipal heat supply plant with negligible pollution. Waste heat is negligible, gaseous radioactivity release is negligible, and there is no liquid radwaste release. Economic comparisons show that the SECURE plant is competitive with current fossil-fueled alternatives. Expected future increase in energy raw material prices will lead to additional energy cost advantages to the SECURE plant

  9. Solar heat storages in district heating networks

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))

    2007-07-15

    This report gives information on the work carried out and the results obtained in Denmark on storages for large solar heating plants in district heating networks. Especially in Denmark the share of district heating has increased to a large percentage. In 1981 around 33% of all dwellings in DK were connected to a district heating network, while the percentage in 2006 was about 60% (in total 1.5 mio. dwellings). In the report storage types for short term storage and long term storages are described. Short term storages are done as steel tanks and is well established technology widely used in district heating networks. Long term storages are experimental and used in connection with solar heating. A number of solar heating plants have been established with either short term or long term storages showing economy competitive with normal energy sources. Since, in the majority of the Danish district heating networks the heat is produced in co-generation plants, i.e. plants producing both electricity and heat for the network, special attention has been put on the use of solar energy in combination with co-generation. Part of this report describes that in the liberalized electricity market central solar heating plants can also be advantageous in combination with co-generation plants. (au)

  10. Heat pipes for ground heating and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, L L

    1988-01-01

    Different versions of heat pipe ground heating and cooling devices are considered. Solar energy, biomass, ground stored energy, recovered heat of industrial enterprises and ambient cold air are used as energy and cold sources. Heat pipe utilization of air in winter makes it possible to design accumulators of cold and ensures deep freezing of ground in order to increase its mechanical strength when building roadways through the swamps and ponds in Siberia. Long-term underground heat storage systems are considered, in which the solar and biomass energy is accumulated and then transferred to heat dwellings and greenhouses, as well as to remove snow from roadways with the help of heat pipes and solar collectors.

  11. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    Connolly, David; Lund, Henrik; Mathiesen, Brian Vad

    2014-01-01

    compared to 1990 levels. None of these scenarios involve the large-scale implementation of district heating, but instead they focus on the electrification of the heating sector (primarily using heat pumps) and/or the large-scale implementation of electricity and heat savings. In this paper, the potential...... for district heating in the EU between now and 2050 is identified, based on extensive and detailed mapping of the EU heat demand and various supply options. Subsequently, a new ‘district heating plus heat savings’ scenario is technically and economically assessed from an energy systems perspective. The results...... indicate that with district heating, the EU energy system will be able to achieve the same reductions in primary energy supply and carbon dioxide emissions as the existing alternatives proposed. However, with district heating these goals can be achieved at a lower cost, with heating and cooling costs...

  12. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    Hansen, Kenneth; Connolly, David; Lund, Henrik

    2015-01-01

    The cost of heat savings in buildings increase as more heat savings are achieved due to the state of the building stock and hence, alternatives other than savings typically become more economically feasible at a certain level of heat reductions. It is important to identify when the cost of heat...... savings become more expensive than the cost of sustainable heat supply, so society does not overinvest in heat saving measures. This study first investigates the heat saving potentials for different countries in Europe, along with their associated costs, followed by a comparison with alternative ways...... of supplying sustainable heating. Different heat production options are included in terms of individual and community heating systems. Furthermore, the levelised cost of supplying sustainable heat is estimated for both a single technology and from an energy system perspective. The results are analysed...

  13. Motier church - refurbishment of heating system; Kirche Motier Sanierung der Raumheizung

    Energy Technology Data Exchange (ETDEWEB)

    Grizzetti, V.

    2003-07-01

    This final report for the Swiss Federal Office for Energy describes the refurbishment of the space heating system of the historical church in Motier, Switzerland. The 50-year old, inefficient electrical direct heating system of the church, which is a listed building, and the new, heat pump-based system are described. Heating energy is distributed via a warm-air system, geothermal energy provides the primary heat source for the heat pump. Technical details of the heating characteristics and energy consumption of the old and new heating systems are presented in the form of tables and diagrams. The maintenance of the heating system's ventilation unit is also discussed.

  14. District heating with SLOWPOKE energy systems

    International Nuclear Information System (INIS)

    Lynch, G.F.

    1988-03-01

    The SLOWPOKE Energy System, a benign nuclear heat source designed to supply 10 thermal megawatts in the form of hot water for local heating systems in buildings and institutions, is at the forefront of these developments. A demonstration unit has been constructed in Canada and is currently undergoing an extensive test program. Because the nuclear heat source is small, operates at atmospheric pressure, and produces hot water below 100 degrees Celcius, intrinsic safety features will permit minimum operator attention and allow the heat source to be located close to the load and hence to people. In this way, a SLOWPOKE Energy System can be considered much like the oil- or coal-fired furnace it is designed to replace. The low capital investment requirements, coupled with a high degree of localization, even for the first unit, are seen as attractive features for the implementation of SLOWPOKE Energy Systems in many countries

  15. Exergo-economic analysis of finned tube for waste heat recovery including phase change heat transfer

    International Nuclear Information System (INIS)

    Wu, Shuang Ying; Jiu, Jing Rui; Xiao, Lan; Li, You Rong; Liu, Chao; Xu, Jin Liang

    2013-01-01

    In this paper, an exergo-economic criterion, i.e. the net profit per unit transferred heat load, is established from the perspective of exergy recovery to evaluate the performance of finned tube used in waste heat recovery. Also, the dimensionless exergy change number is introduced to investigate the effect of the flow (mechanical) exergy loss rate on the recovered thermal exergy. Selecting R245fa as a working fluid and exhaust flue gas as a heat source, the effects of the internal Reynolds number Re_i, the external Reynolds number Re_o , the unit cost of thermal exergy ε_q , the geometric parameter of finned tube η_oβ and the phase change temperature T_v etc. on the performance of finned tube are discussed in detail. The results show that the higher T_v and η_oβ, and lower Re_i may lead to the negligible flow(mechanical) exergy loss rate. There exists an optimal value of Re_i where the net profit per unit transferred heat load peaks, while the variations of Re_o, ε_q and T_v cause monotonic change of the net profit per unit transferred heat load. The phase change temperature exerts relatively greater influence on the exergo-economic performance of finned tube in comparison with other parameters. And there exists a critical phase change temperature, where the net profit per unit transferred heat load is equal to zero.

  16. Experimental analysis of an air–water heat pump with micro-channel heat exchanger

    International Nuclear Information System (INIS)

    Brignoli, Riccardo; Cecchinato, Luca; Zilio, Claudio

    2013-01-01

    A multi-port extruded (MPE) aluminium flat tube air heat exchanger was compared to a round tube finned coil (FC). The MPE heat exchanger has parallel flow vertical tube configuration with headers in horizontal position and conventional folded louvred fins. The two heat exchangers were mounted on a 10 kW cooling capacity R410A packaged air heat pump. They were sized to approximately obtain the same cooling and heating capacities in chiller and heating mode, respectively. Climatic room steady state tests without frosting phenomena occurring during heat pump operation, demonstrated that the round tube and the flat tube heat exchanger performance are comparable. The MPE heat exchanger was tested with different refrigerant inlet distributor/outlet tubes configurations to investigate the effect of liquid refrigerant distribution. Cycling frosting/defrosting operations were tested with two equivalent machines placed in parallel outdoor and working at full load condition, one of the units was equipped with the MPE heat exchanger while the other mounted a standard finned coil. Penalization factors were analytically introduced to evaluate frosting associated heating energy and energy efficiency degradation. Test results indicate that both the heat pumps are penalized by frost formation but both the penalization factors are higher for the MPE-unit than the FC-unit one in the −6 to 4 °C air dry bulb temperature range. For the two units, a roughly linear dependence of the heating energy penalization factor and of the energy efficiency factor from the difference between outdoor air and saturated air at the evaporation temperature humidity ratio can be pointed out. - Highlights: ► A multi-port aluminium flat tube heat exchanger was compared to a round tube finned one in a heat pump application. ► In steady state tests without frosting the round and the flat tube heat exchanger are comparable. ► Different inlet distributor/outlet tubes configurations were tested to

  17. Heat losses and thermal performance of commercial combined solar and pellet heating systems

    OpenAIRE

    Fiedler, Frank; Persson, Tomas; Bales, Chris; Nordlander, Svante

    2004-01-01

    Various pellet heating systems are marketed in Sweden, some of them in combination with a solar heating system. Several types of pellet heating units are available and can be used for a combined system. This article compares four typical combined solar and pellet heating systems: System 1 and 2 two with a pellet stove, system 3 with a store integrated pellet burner and system 4 with a pellet boiler. The lower efficiency of pellet heaters compared to oil or gas heaters increases the primary en...

  18. Discussion on application of water source heat pump technology to uranium mines

    International Nuclear Information System (INIS)

    An Qiang

    2011-01-01

    Application of water source heat pump units in recovering waste heat from uranium mines is discussed, and several forms of waste heat recovery are introduced. The problems in the application of water source heat pump technology are analyzed. Analysis results show that the water source heat pump technology has broad application prospects in uranium mines, and it is a way to exchange existing structure of heat and cold sources in uranium mines. (authors)

  19. RF accelerating unit installed in the PSB

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    RF accelerating unit installed in the PSB ring between two bending magnets. Cool air from a heat exchanger is injected into the four cavities from the central feeder and the hot air recirculated via the lateral ducts.

  20. Heat planning for fossil-fuel-free district heating areas with extensive end-use heat savings: A case study of the Copenhagen district heating area in Denmark

    International Nuclear Information System (INIS)

    Harrestrup, M.; Svendsen, S.

    2014-01-01

    The Danish government plans to make the Danish energy system to be completely free of fossil fuels by 2050 and that by 2035 the energy supply for buildings and electricity should be entirely based on renewable energy sources. To become independent from fossil fuels, it is necessary to reduce the energy consumption of the existing building stock, increase energy efficiency, and convert the present heat supply from fossil fuels to renewable energy sources. District heating is a sustainable way of providing space heating and domestic hot water to buildings in densely populated areas. This paper is a theoretical investigation of the district heating system in the Copenhagen area, in which heat conservation is related to the heat supply in buildings from an economic perspective. Supplying the existing building stock from low-temperature energy resources, e.g. geothermal heat, might lead to oversized heating plants that are too expensive to build in comparison with the potential energy savings in buildings. Long-term strategies for the existing building stock must ensure that costs are minimized and that investments in energy savings and new heating capacity are optimized and carried out at the right time. - Highlights: • We investigate how much heating consumption needs to be reduced in a district heating area. • We examine fossil-fuel-free supply vs. energy conservations in the building stock. • It is slightly cost-beneficial to invest in energy renovation from today for a societal point of view. • It is economically beneficial for district heating companies to invest in energy renovations from today. • The cost per delivered heat unit is lower when energy renovations are carried out from today

  1. Evolución en diseño y tecnología, en las unidades terminales de calefacción = Design and technology design in the terminal units of heating

    Directory of Open Access Journals (Sweden)

    Manuel Islán

    2013-12-01

    Full Text Available Resumen Desde tiempos romanos se han utilizado calentadores para hacer más confortables los espacios habitados. El hipocausto romano, un tipo de radiador utilizado en la construcción, se encuentra descrito en el siglo XV a.C. Después de la caída del Imperio Romano, la calefacción volvió como chimeneas más primitivas durante casi mil años. El uso de vapor en las máquinas de potencia al comienzo de la Revolución Industrial y los conocimientos adquiridos en el manejo de fluidos fue un avance significativo. Más tarde, el vapor fue sustituido por el agua y el carbón y la madera por gas. El radiador de calefacción que contribuyó de manera significativa a los sistemas de calefacción central moderna fue inventado por Franz San Galli en una forma temprana , entre 1855 y 1857. Joseph Nason y Robert Brigss también diseñaron y produjeron un radiador utilizando tubos de hierro forjado verticales atornillados en una base de fundición de hierro en 1863. El progreso en los últimos años en esta técnica es el responsable de las instalaciones de calefacción y calentadores modernos. Hoy en día, han experimentado una evolución desde simples diseños funcionales sin preocuparse por aspectos estéticos, hasta nuestro tiempo en que se exigen nuevos diseños más estéticos y eficientes. Abstract Since Romans times heaters have been used to make more confortable the inhabited spaces. The Roman hypocaust, a type of radiator for building space heating, was described in 15 AD. After the collapse of the Roman Empire, heating reverted to more primitive fireplaces for almost a thousand years. The use of vapour in the power machines at the beginning of the Industrial Revolution and the knowledge gained in the fluid handling was a significant progress. Later on, the vapour was substituted by water, and the coal and wood by gas. The heating radiator that significantly contributed to modern central heating systems was invented by Franz San Galli in an

  2. Control system for fluid heated steam generator

    Science.gov (United States)

    Boland, J.F.; Koenig, J.F.

    1984-05-29

    A control system for controlling the location of the nucleate-boiling region in a fluid heated steam generator comprises means for measuring the temperature gradient (change in temperature per unit length) of the heating fluid along the steam generator; means for determining a control variable in accordance with a predetermined function of temperature gradients and for generating a control signal in response thereto; and means for adjusting the feedwater flow rate in accordance with the control signal.

  3. Rotary magnetic heat pump

    Science.gov (United States)

    Kirol, L.D.

    1987-02-11

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

  4. Transient Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  5. Thulium-170 heat source

    Science.gov (United States)

    Walter, Carl E.; Van Konynenburg, Richard; VanSant, James H.

    1992-01-01

    An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

  6. District heating in Switzerland

    International Nuclear Information System (INIS)

    Herzog, F.

    1991-01-01

    District heating has been used in Switzerland for more than 50 years. Its share of the heat market is less than 3% today. An analysis of the use of district heating in various European countries shows that a high share of district heating in the heat market is always dependent on ideal conditions for its use. Market prospects and possible future developments in the use of district heating in Switzerland are described in this paper. The main Swiss producers and distributors of district heating are members of the Association of District Heating Producers and Distributors. This association supports the installation of district heating facilities where ecological, energetical and economic aspects indicate that district heating would be a good solution. (author) 2 tabs., 6 refs

  7. Generating Units

    Data.gov (United States)

    Department of Homeland Security — Generating Units are any combination of physically connected generators, reactors, boilers, combustion turbines, and other prime movers operated together to produce...

  8. Resistively heated shape memory polymer device

    Energy Technology Data Exchange (ETDEWEB)

    Marion, III, John E.; Bearinger, Jane P.; Wilson, Thomas S.; Maitland, Duncan J.

    2017-09-05

    A resistively heated shape memory polymer device is made by providing a rod, sheet or substrate that includes a resistive medium. The rod, sheet or substrate is coated with a first shape memory polymer providing a coated intermediate unit. The coated intermediate unit is in turn coated with a conductive material providing a second intermediate unit. The second coated intermediate unit is in turn coated with an outer shape memory polymer. The rod, sheet or substrate is exposed and an electrical lead is attached to the rod, sheet or substrate. The conductive material is exposed and an electrical lead is attached to the conductive material.

  9. Resistively heated shape memory polymer device

    Energy Technology Data Exchange (ETDEWEB)

    Marion, III, John E.; Bearinger, Jane P.; Wilson, Thomas S.; Maitland, Duncan J.

    2016-10-25

    A resistively heated shape memory polymer device is made by providing a rod, sheet or substrate that includes a resistive medium. The rod, sheet or substrate is coated with a first shape memory polymer providing a coated intermediate unit. The coated intermediate unit is in turn coated with a conductive material providing a second intermediate unit. The second coated intermediate unit is in turn coated with an outer shape memory polymer. The rod, sheet or substrate is exposed and an electrical lead is attached to the rod, sheet or substrate. The conductive material is exposed and an electrical lead is attached to the conductive material.

  10. Solar/electric heating systems for the future energy system

    Energy Technology Data Exchange (ETDEWEB)

    Furbo, S.; Dannemand, M.; Perers, B. [and others

    2013-05-15

    The aim of the project is to elucidate how individual heating units for single family houses are best designed in order to fit into the future energy system. The units are based on solar energy, electrical heating elements/heat pump, advanced heat storage tanks and advanced control systems. Heat is produced by solar collectors in sunny periods and by electrical heating elements/heat pump. The electrical heating elements/heat pump will be in operation in periods where the heat demand cannot be covered by solar energy. The aim is to use the auxiliary heating units when the electricity price is low, e.g. due to large electricity production by wind turbines. The unit is equipped with an advanced control system where the control of the auxiliary heating is based on forecasts of the electricity price, the heat demand and the solar energy production. Consequently, the control is based on weather forecasts. Three differently designed heating units are tested in a laboratory test facility. The systems are compared on the basis of: 1) energy consumption for the auxiliary heating; 2) energy cost for the auxiliary heating; 3) net utilized solar energy. Starting from a normal house a solar combi system (for hot water and house heating) can save 20-30% energy cost, alone, depending on sizing of collector area and storage volume. By replacing the heat storage with a smart tank based on electric heating elements and a smart control based on weather/load forecast and electricity price information 24 hours ahead, another 30-40% can be saved. That is: A solar heating system with a solar collector area of about 10 m{sup 2}, a smart tank based on electric heating element and a smart control system, can reduce the energy costs of the house by at least 50%. No increase of heat storage volume is needed to utilize the smart control. The savings in % are similar for different levels of building insulation. As expected a heat pump in the system can further reduce the auxiliary electricity

  11. A Modified Entropy Generation Number for Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    This paper demonstrates the difference between the entropy generation number method proposed by Bejian and the method of entropy generation per unit amount of heat transferred in analyzing the ther-modynamic performance of heat exchangers,points out the reason for leading to the above difference.A modified entropy generation number for evaluating the irreversibility of heat exchangers is proposed which is in consistent with the entropy generation per unit amount of heat transferred in entropy generation analysis.The entropy generated by friction is also investigated.Results show that when the entropy generated by friction in heat exchangers in taken into account,there is a minimum total entropy generation number while the NTU and the ratio of heat capacity rates vary.The existence of this minimum is the prerequisite of heat exchanger optimization.

  12. Possible uses of nuclear energy in central heating of Ankara

    International Nuclear Information System (INIS)

    Agirsoy, L.

    1987-01-01

    In this master thesis, a study was carried out for the district heating of the plateau region where the population and air pollution densities are the highest. First the heat requirements of differently populated regions were calculated, then by taking different temperature decreases of hot water in buildings; flow rates, pipe diameters and pressure losses corres-ponding to these temperature decreases were obtained. An optimum division of total heat load as peak and base loads was studied and it was seen that the unit heat cost could be lowered by employing two stations for the heating of buildings. The optimum division and unit heat cost calculations were carried out for various alternative heating systems and it was seen that nuclear combined cycle base-load station and a peak-load station operating on fuel-oil was obtained to be the most advantageous system from an economic point of view. (author)

  13. Analysis of Heat Transfer

    International Nuclear Information System (INIS)

    2003-08-01

    This book deals with analysis of heat transfer which includes nonlinear analysis examples, radiation heat transfer, analysis of heat transfer in ANSYS, verification of analysis result, analysis of heat transfer of transition with automatic time stepping and open control, analysis of heat transfer using arrangement of ANSYS, resistance of thermal contact, coupled field analysis such as of thermal-structural interaction, cases of coupled field analysis, and phase change.

  14. Heating in toroidal plasmas

    International Nuclear Information System (INIS)

    Canobbio, E.

    1981-01-01

    This paper reports on the 2nd Joint Grenoble-Varenna International Symposium on Heating in Toroidal Plasmas, held at Como, Italy, from the 3-12 September 1980. Important problems in relation to the different existing processes of heating. The plasma were identified and discussed. Among others, the main processes discussed were: a) neutral beam heating, b) ion-(electron)-cyclotron resonance heating, c) hybrid resonance and low frequency heating

  15. Introduction to heat transfer

    CERN Document Server

    SUNDÉN, B

    2012-01-01

    Presenting the basic mechanisms for transfer of heat, Introduction to Heat Transfer gives a deeper and more comprehensive view than existing titles on the subject. Derivation and presentation of analytical and empirical methods are provided for calculation of heat transfer rates and temperature fields as well as pressure drop. The book covers thermal conduction, forced and natural laminar and turbulent convective heat transfer, thermal radiation including participating media, condensation, evaporation and heat exchangers.

  16. Heat exchange apparatus

    International Nuclear Information System (INIS)

    Thurston, G.C.; McDaniels, J.D.; Gertsch, P.R.

    1979-01-01

    The present invention relates to heat exchangers used for transferring heat from the gas cooled core of a nuclear reactor to a secondary medium during standby and emergency conditions. The construction of the heat exchanger described is such that there is a minimum of welds exposed to the reactor coolant, the parasitic heat loss during normal operation of the reactor is minimized and the welds and heat transfer tubes are easily inspectable. (UK)

  17. Heat cascading regenerative sorption heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1995-01-01

    A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

  18. Influence of Host Interleukin-10 Polymorphisms on Development of Traveler's Diarrhea Due to Heat-Labile Enterotoxin-Producing Escherichia coli in Travelers from the United States Who Are Visiting Mexico▿

    Science.gov (United States)

    Flores, Jose; DuPont, Herbert L.; Lee, Stephanie A.; Belkind-Gerson, Jaime; Paredes, Mercedes; Mohamed, Jamal A.; Armitige, Lisa Y.; Guo, Dong-Chuan; Okhuysen, Pablo C.

    2008-01-01

    Up to 60% of U.S. visitors to Mexico develop traveler's diarrhea (TD), mostly due to enterotoxigenic Escherichia coli (ETEC) strains that produce heat-labile (LT) and/or heat-stable (ST) enterotoxins. Distinct single-nucleotide polymorphisms (SNPs) within the interleukin-10 (IL-10) promoter have been associated with high, intermediate, or low production of IL-10. We conducted a prospective study to investigate the association of SNPs in the IL-10 promoter and the occurrence of TD in ETEC LT-exposed travelers. Sera from U.S. travelers to Mexico collected on arrival and departure were studied for ETEC LT seroconversion by using cholera toxin as the antigen. Pyrosequencing was performed to genotype IL-10 SNPs. Stools from subjects who developed diarrhea were also studied for other enteropathogens. One hundred twenty-one of 569 (21.3%) travelers seroconverted to ETEC LT, and among them 75 (62%) developed diarrhea. Symptomatic seroconversion was more commonly seen in subjects who carried a genotype producing high levels of IL-10; it was seen in 83% of subjects with the GG genotype versus 54% of subjects with the AA genotype at IL-10 gene position −1082 (P, 0.02), in 71% of those with the CC genotype versus 33% of those with the TT genotype at position −819 (P, 0.005), and in 71% of those with the CC genotype versus 38% of those with the AA genotype at position −592 (P, 0.02). Travelers with the GCC haplotype were more likely to have symptomatic seroconversion than those with the ATA haplotype (71% versus 38%; P, 0.002). Travelers genetically predisposed to produce high levels of IL-10 were more likely to experience symptomatic ETEC TD. PMID:18579697

  19. Influence of host interleukin-10 polymorphisms on development of traveler's diarrhea due to heat-labile enterotoxin-producing Escherichia coli in travelers from the United States who are visiting Mexico.

    Science.gov (United States)

    Flores, Jose; DuPont, Herbert L; Lee, Stephanie A; Belkind-Gerson, Jaime; Paredes, Mercedes; Mohamed, Jamal A; Armitige, Lisa Y; Guo, Dong-Chuan; Okhuysen, Pablo C

    2008-08-01

    Up to 60% of U.S. visitors to Mexico develop traveler's diarrhea (TD), mostly due to enterotoxigenic Escherichia coli (ETEC) strains that produce heat-labile (LT) and/or heat-stable (ST) enterotoxins. Distinct single-nucleotide polymorphisms (SNPs) within the interleukin-10 (IL-10) promoter have been associated with high, intermediate, or low production of IL-10. We conducted a prospective study to investigate the association of SNPs in the IL-10 promoter and the occurrence of TD in ETEC LT-exposed travelers. Sera from U.S. travelers to Mexico collected on arrival and departure were studied for ETEC LT seroconversion by using cholera toxin as the antigen. Pyrosequencing was performed to genotype IL-10 SNPs. Stools from subjects who developed diarrhea were also studied for other enteropathogens. One hundred twenty-one of 569 (21.3%) travelers seroconverted to ETEC LT, and among them 75 (62%) developed diarrhea. Symptomatic seroconversion was more commonly seen in subjects who carried a genotype producing high levels of IL-10; it was seen in 83% of subjects with the GG genotype versus 54% of subjects with the AA genotype at IL-10 gene position -1082 (P, 0.02), in 71% of those with the CC genotype versus 33% of those with the TT genotype at position -819 (P, 0.005), and in 71% of those with the CC genotype versus 38% of those with the AA genotype at position -592 (P, 0.02). Travelers with the GCC haplotype were more likely to have symptomatic seroconversion than those with the ATA haplotype (71% versus 38%; P, 0.002). Travelers genetically predisposed to produce high levels of IL-10 were more likely to experience symptomatic ETEC TD.

  20. Heat transfer from internally heated hemispherical pools

    International Nuclear Information System (INIS)

    Gabor, J.D.; Ellsion, P.G.; Cassulo, J.C.

    1980-01-01

    Experiments were conducted on heat transfer from internally heated ZnSO 4 -H 2 O pools to the walls of hemispherical containers. This experimental technique provides data for a heat transfer system that has to date been only theoretically treated. Three different sizes of copper hemispherical containers were used: 240, 280, 320 mm in diameter. The pool container served both as a heat transfer surface and as an electrode. The opposing electrode was a copper disk, 50 mm in diameter located at the top of the pool in the center. The top surface of the pool was open to the atmosphere

  1. Development and fabrication of heat-sterilizable inhalation therapy equipment

    Science.gov (United States)

    Irons, A. S.

    1974-01-01

    The development of a completely heat sterilizable intermittent positive pressure breathing (IPPB) ventilator in an effort to reduce the number of hospital acquired infections is reported. After appropriate changes in materials and design were made, six prototype units were fabricated and were successfully field tested in local hospitals. Most components of the modified ventilators are compatible with existing machines. In all but a few instances, such as installation of bacteria-retentive filters and a modified venturi, the change over from non-heat-sterilizable to sterilizable units was accomplished by replacement of heat labile materials with heat stable materials.

  2. The prospects for nuclear heating in Hungary

    International Nuclear Information System (INIS)

    Papp, I.; Lynch, G.F.

    1989-09-01

    In assessing alternative nuclear heat sources, a joint study was undertaken between Canada and Hungary to determine the feasibility of using the SLOWPOKE Energy System that has recently been developed. The SLOWPOKE Energy System is a benign nuclear heat source designed to supply 10 thermal megawatts in the form of hot water for local heating systems in buildings and institutions. It uses a combination of inherent safety features, including natural convection circulation and negative reactivity coefficients, and engineered features to ensure an extremely safe system. A SLOWPOKE demonstration heating reactor has been constructed in Canada. The unit started operation in July 1987 and is currently undergoing an extensive test program. Since the nuclear heat source is small, operates at atmospheric pressure, and produces hot water below 100 deg. C, the complex high-pressure, and high-temperature systems essential for electricity production are eliminated. As a result, the nuclear heat source can be located close to the load and will require a minimum of operator attention. In this way, a SLOWPOKE Energy System can be considered much like the oil- or natural gas fired furnace it is designed to replace. The extensive use of hot water district heating systems in Hungary offers the opportunity to exploit such simple nuclear systems as base load heat sources without an extensive retrofit of the existing systems. In addition, the studies have concluded that there are many economically attractive sites for 10 MW SLOWPOKE Energy Systems within the existing networks. The low capital investment requirements, coupled with a high degree of localization, even for the first unit, are seen as additional factors that facilitate the transfer of the technology to Hungary. Simple nuclear heat sources, such as the SLOWPOKE Energy System, when applied to the Hungarian district heating systems, offer the prospects of a significant reduction in the dependence on imported fossil fuels in the

  3. Regenerator heat exchanger – calculation of heat recovery efficiency and pressure loss

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per Kvols

    Performance of heat exchangers is determined based on two main parameters: efficiency to exchange / recover heat and pressure loss due to friction between fluid and exchanger surfaces. These two parameters are contradicting each other which mean that the higher is efficiency the higher becomes...... pressure loss. The aim of the optimized design of heat exchanger is to reach the highest or the required heat efficiency and at the same time to keep pressure losses as low as possible keeping total exchanger size within acceptable size. In this report is presented analytical calculation method...... to calculate efficiency and pressure loss in the regenerator heat exchanger with a fixed matrix that will be used in the decentralized ventilation unit combined in the roof window. Moreover, this study presents sensitivity study of regenerator heat exchanger performance, taking into account, such parameters as...

  4. Building Space Heating with a Solar-Assisted Heat Pump Using Roof-Integrated Solar Collectors

    Directory of Open Access Journals (Sweden)

    Zhiyong Yang

    2011-03-01

    Full Text Available A solar assisted heat pump (SAHP system was designed by using a roof-integrated solar collector as the evaporator, and then it was demonstrated to provide space heating for a villa in Tianjin, China. A building energy simulation tool was used to predict the space heating load and a three dimensional theoretical model was established to analyze the heat collection performance of the solar roof collector. A floor radiant heating unit was used to decrease the energy demand. The measurement results during the winter test period show that the system can provide a comfortable living space in winter, when the room temperature averaged 18.9 °C. The average COP of the heat pump system is 2.97 and with a maximum around 4.16.

  5. Process for forming thin film, heat treatment process of thin film sheet, and heat treatment apparatus therefor

    International Nuclear Information System (INIS)

    Watanabe, S.

    1984-01-01

    The invention provides a process for forming a magnetic thin film on a base film, a heat treatment process of a thin film sheet consisting of the base film and the magnetic thin film, and an apparatus for performing heat treatment of the thin film sheet. Tension applied to the thin film sheet is substantially equal to that applied to the base film when the magnetic thin film is formed thereon. Then, the thin film sheet is treated with heat. The thin film sheet is heated with a given temperature gradient to a reactive temperature at which heat shrinkage occurs, while the tension is being applied thereto. Thereafter, the thin film sheet to which the tension is still applied is cooled with substantially the same temperature gradient as applied in heating. The heat treatment apparatus has a film driving unit including a supply reel, a take-up reel, a drive source and guide rollers; a heating unit including heating plates, heater blocks and a temperature controller for heating the sheet to the reactive temperature; and a heat insulating unit including a thermostat and another temperature controller for maintaining the sheet at the nonreactive temperature which is slightly lower than the reactive temperature

  6. Heat pump augmentation of nuclear process heat

    International Nuclear Information System (INIS)

    Koutz, S.L.

    1986-01-01

    A system is described for increasing the temperature of a working fluid heated by a nuclear reactor. The system consists of: a high temperature gas cooled nuclear reactor having a core and a primary cooling loop through which a coolant is circulated so as to undergo an increase in temperature, a closed secondary loop having a working fluid therein, the cooling and secondary loops having cooperative association with an intermediate heat exchanger adapted to effect transfer of heat from the coolant to the working fluid as the working fluid passes through the intermediate heat exchanger, a heat pump connected in the secondary loop and including a turbine and a compressor through which the working fluid passes so that the working fluid undergoes an increase in temperature as it passes through the compressor, a process loop including a process chamber adapted to receive a process fluid therein, the process chamber being connected in circuit with the secondary loop so as to receive the working fluid from the compressor and transfer heat from the working fluid to the process fluid, a heat exchanger for heating the working fluid connected to the process loop for receiving heat therefrom and for transferring heat to the secondary loop prior to the working fluid passing through the compressor, the secondary loop being operative to pass the working fluid from the process chamber to the turbine so as to effect driving relation thereof, a steam generator operatively associated with the secondary loop so as to receive the working fluid from the turbine, and a steam loop having a feedwater supply and connected in circuit with the steam generator so that feedwater passing through the steam loop is heated by the steam generator, the steam loop being connected in circuit with the process chamber and adapted to pass steam to the process chamber with the process fluid

  7. Heat recovery in industry

    Energy Technology Data Exchange (ETDEWEB)

    Steimle, F; Paul, J [Essen Univ. (Gesamthochschule) (Germany, F.R.)

    1977-05-01

    The waste heat of industrial furnaces and other heat-consuming installations can be utilized by recuperative processes in the furnace and by energy cascades. Economy and the need for an external supply of energy are closely connected. Straight cascades can hardly be realized and if the required temperature gradient is too great such heat should be utilized repeatedly if possible by recycling through heat pumps. The possibilities depend on the relevant temperature since the technology available for this differs in its state of development. The low-temperature waste heat from the final stage can be used for space-heating and water heating by heat exchangers and heat pumps and thus be put to a useful purpose.

  8. Use of solar energy for heat supply under conditions of the Socialist Federated Republic of Yugoslavia

    Energy Technology Data Exchange (ETDEWEB)

    Savic, B.

    1981-01-01

    The characteristics of a flat solar energy collector are used to determine the specific heat productivity of the solar unit under meteorological conditions of Belgrade. The evaluation is made with regard for experimental data of year-round operation of hot water supply units and the seasonal use of heating units.

  9. Applying Thermodynamics to Fossil Fuels: Heats of Combustion from Elemental Compositions.

    Science.gov (United States)

    Lloyd, William G.; Davenport, Derek A.

    1980-01-01

    Discussed are the calculations of heats of combustions of some selected fossil fuel compounds such as some foreign shale oils and United States coals. Heating values for coal- and petroleum-derived fuel oils are also presented. (HM)

  10. Major heat exchanger performance in Ontario Hydro-operated CANDU nuclear generating stations

    International Nuclear Information System (INIS)

    Dueck, D.G.

    1980-01-01

    The performance of heat exchangers is described in terms of their impact on the unit in the form of forced outages and deratings as well as incapability due to scheduled outages. Some major problems with heat exchangers are highlighted. (auth)

  11. New nuclear heat sources for district heating

    International Nuclear Information System (INIS)

    Lerouge, B.

    1975-01-01

    The means by which urban oil heating may be taken over by new energy sources, especially nuclear, are discussed. Several possibilities exist: pressurized water reactors for high powers, and low-temperature swimming-pool-type process-heat reactors for lower powers. Both these cases are discussed [fr

  12. Heat transfer system

    Science.gov (United States)

    Not Available

    1980-03-07

    A heat transfer system for a nuclear reactor is described. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

  13. Basic heat transfer

    CERN Document Server

    Bacon, D H

    2013-01-01

    Basic Heat Transfer aims to help readers use a computer to solve heat transfer problems and to promote greater understanding by changing data values and observing the effects, which are necessary in design and optimization calculations.The book is concerned with applications including insulation and heating in buildings and pipes, temperature distributions in solids for steady state and transient conditions, the determination of surface heat transfer coefficients for convection in various situations, radiation heat transfer in grey body problems, the use of finned surfaces, and simple heat exc

  14. Microscale Regenerative Heat Exchanger

    Science.gov (United States)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2006-01-01

    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  15. Heat extraction from turbines of Czechoslovak nuclear power plants for district heating

    International Nuclear Information System (INIS)

    Drahy, J.

    1985-01-01

    Two design are described of SKODA extraction turbines for Czechoslovak nuclear power plants with WWER-440 and WWER-1000 reactors. 220 MW steam turbines were originally designed as pure condensation turbines with uncontrolled steam extraction. Optimal ways are now being sought for their use for heating hot water for district heating. For district heating of the town of Trnava, the nuclear power plant at Jaslovske Bohunice will provide a two-step heating of water from 70 to 120 degC with a heat supply of 60 MW th from one turbine unit. The ratio of obtained heat power to lost electric power is 5.08. Investigations showed the possibility of extracting 85 MW th of heat from uncontrolled steam extraction, this at three-step water heating from 60 to 145 degC, the ratio of gained and lost power being 7.14. Information is presented on the SKODA 220 MW turbine with steam extraction for heat supply purposes and on the 1000 MW turbine with 893 MW th heat extraction. The specifications of both types are given. (Pu)

  16. Thermoacoustic refrigerators and engines comprising cascading stirling thermodynamic units

    Science.gov (United States)

    Backhaus, Scott; Swift, Greg

    2013-06-25

    The present invention includes a thermoacoustic assembly and method for improved efficiency. The assembly has a first stage Stirling thermal unit comprising a main ambient heat exchanger, a regenerator and at least one additional heat exchanger. The first stage Stirling thermal unit is serially coupled to a first end of a quarter wavelength long coupling tube. A second stage Stirling thermal unit comprising a main ambient heat exchanger, a regenerator, and at least one additional heat exchanger, is serially coupled to a second end of the quarter wavelength long coupling tube.

  17. Malone-brayton cycle engine/heat pump

    Science.gov (United States)

    Gilmour, Thomas A.

    1994-07-01

    A machine, such as a heat pump, and having an all liquid heat exchange fluid, operates over a more nearly ideal thermodynamic cycle by adjustment of the proportionality of the volumetric capacities of a compressor and an expander to approximate the proportionality of the densities of the liquid heat exchange fluid at the chosen working pressures. Preferred forms of a unit including both the compressor and the expander on a common shaft employs difference in axial lengths of rotary pumps of the gear or vane type to achieve the adjustment of volumetric capacity. Adjustment of the heat pump system for differing heat sink conditions preferably employs variable compression ratio pumps.

  18. The analysis of thermal network of district heating system from investor point of view

    Science.gov (United States)

    Takács, Ján; Rácz, Lukáš

    2016-06-01

    The hydraulics of a thermal network of a district heating system is a very important issue, to which not enough attention is often paid. In this paper the authors want to point out some of the important aspects of the design and operation of thermal networks in district heating systems. The design boundary conditions of a heat distribution network and the requirements on active pressure - circulation pump - influencing the operation costs of the centralized district heating system as a whole, are analyzed in detail. The heat generators and the heat exchange stations are designed according to the design heat loads after thermal insulation, and modern boiler units are installed in the heating plant.

  19. The possibilities of heat pumps utilisation for family houses and flats fumigation

    Directory of Open Access Journals (Sweden)

    Ján Pinka

    2006-10-01

    Full Text Available Heat pumps (HPs with the help of electricity use a renewable energy source to supply heat for homes or industrial buildings and to heat tap water. HP is a heating unit that will provide us with heat for our home for some 20 to 30 years to come and has a potential to replace traditional heating systems powered by gas, oil or coal. At this time, there is no other heating system that supplies clean heat with the help of up to 80 per cent of the renewable solar energy during all year.

  20. Heat transfer enhancement

    International Nuclear Information System (INIS)

    Hasatani, Masanobu; Itaya, Yoshinori

    1985-01-01

    In order to develop energy-saving techniques and new energy techniques, and also most advanced techniques by making industrial equipment with high performance, heat transfer performance frequently becomes an important problem. In addition, the improvement of conventional heat transfer techniques and the device of new heat transfer techniques are often required. It is most proper that chemical engineers engage in the research and development for enhancing heat transfer. The research and development for enhancing heat transfer are important to heighten heat exchange efficiency or to cool equipment for preventing overheat in high temperature heat transfer system. In this paper, the techniques of enhancing radiative heat transfer and the improvement of radiative heat transfer characteristics are reported. Radiative heat transfer is proportional to fourth power of absolute temperature, and it does not require any heat transfer medium, but efficient heat-radiation converters are necessary. As the techniques of enhancing radiative heat transfer, the increase of emission and absorption areas, the installation of emissive structures and the improvement of radiative characteristics are discussed. (Kako, I.)

  1. Heat networks in France in 2014. Heat networks: which price for the consumer?

    International Nuclear Information System (INIS)

    Reynaud, Didier; Gong, Zheng; Moreau, Sylvain; Bottin, Anne; Reperant, Patricia

    2016-04-01

    A first document publishes and comments various statistics regarding heat networks in France in 2014: distribution in terms of quantity of supplied heat, main urban units, distribution in terms of urban unit size and in terms of community type (land, isolated town, outskirts, centre town). It also indicates the types, percentages and evolution of energies consumed in these heat networks, the shares of fossil and renewable energies, and the distribution of networks in terms of energy type. Some regional data are briefly commented (energy shares in each region, number of primary housing connected to an urban heating network). This publication also indicates methodological aspects and the definitions of the main components and characteristics of a heat network. Notably based on some of these data, the second document comments the price of heat supplied in these heat networks in 2014 as these prices are not regulated and depend on agreements between clients and providers. These prices are analysed in terms of linear thermal density, of heat quantity supplied by delivery point, of sector (industry, housing, office building), of rate of renewable energy, and of operator status (public service delegation or private ownership)

  2. Design study of plastic film heat exchanger

    Science.gov (United States)

    Guyer, E. C.; Brownell, D. L.

    1986-02-01

    This report presents the results of an effort to develop and design a unique thermoplastic film heat exchanger for use in an industrial heat pump evaporator system and other energy recovery applications. The concept for the exchanger is that of individual heat exchange elements formed by two adjoining and freely hanging plastic films. Liquid flows downward in a regulated fashion between the films due to the balance of hydrostatic and frictional forces. The fluid stream on the outside of film may be a free-falling liquid film, a condensing gas, or a noncondensing gas. The flow and structural principles are similar to those embodied in an earlier heat exchange system developed for use in waste water treatment systems (Sanderson). The design allows for high heat transfer rates while working within the thermal and structural limitations of thermoplastic materials. The potential of this new heat exchanger design lies in the relatively low cost of plastic film and the high inherent corrosion and fouling resistance. This report addresses the selection of materials, the potential heat transf er performance, the mechanical design and operation of a unit applied in a low pressure steam recovery system, and the expected selling price in comparison to conventional metallic shell and tube heat exchangers.

  3. Lowering district heating temperatures – Impact to system performance in current and future Danish energy scenarios

    DEFF Research Database (Denmark)

    Ommen, Torben; Markussen, Wiebke Brix; Elmegaard, Brian

    2016-01-01

    CHP (Combined heat and power) production in connection with DH (district heating) systems has previously demonstrated a significant reduction in primary energy consumption. With extended installation of intermittent sustainable sources, such as eg. wind turbines rather than thermal units, the cha......CHP (Combined heat and power) production in connection with DH (district heating) systems has previously demonstrated a significant reduction in primary energy consumption. With extended installation of intermittent sustainable sources, such as eg. wind turbines rather than thermal units...

  4. Interactions between urban heat islands and heat waves

    Science.gov (United States)

    Zhao, Lei; Oppenheimer, Michael; Zhu, Qing; Baldwin, Jane W.; Ebi, Kristie L.; Bou-Zeid, Elie; Guan, Kaiyu; Liu, Xu

    2018-03-01

    Heat waves (HWs) are among the most damaging climate extremes to human society. Climate models consistently project that HW frequency, severity, and duration will increase markedly over this century. For urban residents, the urban heat island (UHI) effect further exacerbates the heat stress resulting from HWs. Here we use a climate model to investigate the interactions between the UHI and HWs in 50 cities in the United States under current climate and future warming scenarios. We examine UHI2m (defined as urban-rural difference in 2m-height air temperature) and UHIs (defined as urban-rural difference in radiative surface temperature). Our results show significant sensitivity of the interaction between UHI and HWs to local background climate and warming scenarios. Sensitivity also differs between daytime and nighttime. During daytime, cities in the temperate climate region show significant synergistic effects between UHI and HWs in current climate, with an average of 0.4 K higher UHI2m or 2.8 K higher UHIs during HWs than during normal days. These synergistic effects, however, diminish in future warmer climates. In contrast, the daytime synergistic effects for cities in dry regions are insignificant in the current climate, but emerge in future climates. At night, the synergistic effects are similar across climate regions in the current climate, and are stronger in future climate scenarios. We use a biophysical factorization method to disentangle the mechanisms behind the interactions between UHI and HWs that explain the spatial-temporal patterns of the interactions. Results show that the difference in the increase of urban versus rural evaporation and enhanced anthropogenic heat emissions (air conditioning energy use) during HWs are key contributors to the synergistic effects during daytime. The contrast in water availability between urban and rural land plays an important role in determining the contribution of evaporation. At night, the enhanced release of stored

  5. Unit Manning

    National Research Council Canada - National Science Library

    McGinniss, Mike

    2003-01-01

    .... This decision combines two crucial initiatives: first, transforming the Army from an individual soldier replacement system to a unit manning system that enhances cohesion and keeps trained soldiers, leaders, and commanders together longer, thereby...

  6. Detector Unit

    CERN Multimedia

    1960-01-01

    Original detector unit of the Instituut voor Kernfysisch Onderzoek (IKO) BOL project. This detector unit shows that silicon detectors for nuclear physics particle detection were already developed and in use in the 1960's in Amsterdam. Also the idea of putting 'strips' onto the silicon for high spatial resolution of a particle's impact on the detector were implemented in the BOL project which used 64 of these detector units. The IKO BOL project with its silicon particle detectors was designed, built and operated from 1965 to roughly 1977. Detector Unit of the BOL project: These detectors, notably the ‘checkerboard detector’, were developed during the years 1964-1968 in Amsterdam, The Netherlands, by the Natuurkundig Laboratorium of the N.V. Philips Gloeilampen Fabrieken. This was done in close collaboration with the Instituut voor Kernfysisch Onderzoek (IKO) where the read-out electronics for their use in the BOL Project was developed and produced.

  7. Energy Analysis of Cascade Heating with High Back-Pressure Large-Scale Steam Turbine

    Directory of Open Access Journals (Sweden)

    Zhihua Ge

    2018-01-01

    Full Text Available To reduce the exergy loss that is caused by the high-grade extraction steam of traditional heating mode of combined heat and power (CHP generating unit, a high back-pressure cascade heating technology for two jointly constructed large-scale steam turbine power generating units is proposed. The Unit 1 makes full use of the exhaust steam heat from high back-pressure turbine, and the Unit 2 uses the original heating mode of extracting steam condensation, which significantly reduces the flow rate of high-grade extraction steam. The typical 2 × 350 MW supercritical CHP units in northern China were selected as object. The boundary conditions for heating were determined based on the actual climatic conditions and heating demands. A model to analyze the performance of the high back-pressure cascade heating supply units for off-design operating conditions was developed. The load distributions between high back-pressure exhaust steam direct supply and extraction steam heating supply were described under various conditions, based on which, the heating efficiency of the CHP units with the high back-pressure cascade heating system was analyzed. The design heating load and maximum heating supply load were determined as well. The results indicate that the average coal consumption rate during the heating season is 205.46 g/kWh for the design heating load after the retrofit, which is about 51.99 g/kWh lower than that of the traditional heating mode. The coal consumption rate of 199.07 g/kWh can be achieved for the maximum heating load. Significant energy saving and CO2 emission reduction are obtained.

  8. Development of a ceramic heat exchanger for a combined cycle plant with pressurized coal dust combustion. Final report; Entwicklung eines keramischen Waermeaustauschers fuer eine Kombianlage mit Kohlenstaubdruckfeuerung. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Leithner, R.; Ehlers, C.

    2001-12-01

    State of Research: The Pressurized Pulverized Coal Combustion Combined Cycle (PPCCCC) with a directly fired gas turbine can reach electrical efficiencies beyond 50%. The required gas quality upstream the gas turbine has not been reached yet at temperatures above 1000 C. One approach tested is the precipitation of ash and alkalines at temperatures above the ash melting point. This principle contains problems concerning the remaining content of ash and alkalines in the flue gas and damages to the refractory materials due to corrosion. Goal of the Investigation: An alternative process had to be investigated in which the flue gas is cleaned according to the state of the art, i.e. below the ash fusion temperature. This principle requires cooling down the flue gas and heating it up again after cleaning in a high temperature heat exchanger. Method: A ceramic tube-and-shell heat exchanger in a model scale was designed and was operated at realistic conditions in an atmospheric test plant in connection with a high temperture precipitation. Result: The heat exchanger showed a good performance concerning design and material. The expected temperatures were not reached totally because of untight joints. Clogging occurred in the tube entrances at high temperatures because of sintered ash agglomerates. First tests to clean the entrances during operation showed positive results. The ash precipitation by means of a cyclone and ceramic filter candles was performed without difficulties. Conclusion: Avoiding and improving joints will help to achieve higher temperatures. A process of cleaning the tubes in-line has to be introduced to prevent the clogging effects. If this is successfully done for high temperatures, an attractive principle for a PPCCCC-process is available which reaches the gas purity required. (orig.) [German] Derzeitiger Stand der Forschung: Der Kohlenstaubdruckfeuerungs-Kombiprozess mit direkt befeuerter Gasturbine verspricht elektrische Wirkungsgrade ueber 50%. Die

  9. Geothermal rice drying unit in Kotchany, Macedonia

    International Nuclear Information System (INIS)

    Popovski, K.; Dimitrov, K.; Andrejevski, B.; Popovska, S.

    1992-01-01

    A geothermal field in Kotchany (Macedonia) has very advantageous characteristics for direct application purposes. Low content of minerals, moderate temperature (78C) and substantial available geothermal water flow (up to 300 1/s) enabled the establishment of a district heating scheme comprising mainly agricultural and industrial uses. A rice drying unit of 10 t/h capacity was installed 8 years ago, using the geothermal water as the primary heat source. A temperature drop of 75/50C enables the adaptation of conventional drying technology, already proven in practice in the surrounding rice growing region. Water to air heat exchanger and all necessary equipment and materials are of local production, made of copper and carbon steel. The use of such drying units is strongly recommended for the concrete district heating scheme because it offers a very simple geothermal application and enables improvement in the annual heating load factor without high investments in geothermal water distribution lines

  10. The influence of heat exchanger design on the synthesis of heat exchanger networks

    Directory of Open Access Journals (Sweden)

    Liporace F.S.

    2000-01-01

    Full Text Available Heat exchanger network (HEN synthesis has been traditionally performed without accounting for a more detailed unit design, which is important since the final HEN may require unfeasible units. Recently, publications on this matter have appeared, as well as softwares that simultaneously perform synthesis and units design. However, these publications do not clearly show the influence of the new added features on the final HEN. Hence, this work aims at showing that units' design can strongly affect the final HEN. Improvements on heat transfer area and total annual cost estimations, which influence the HEN structural evolution, are the main responsible for that. It is also shown the influence of some design bounds settings, which can indicate an unfeasible unit design and, therefore, the need for a new match search or the maintenance of a loop. An example reported in the literature is used to illustrate the discussion.

  11. Flue gas recovery system for natural gas combined heat and power plant with distributed peak-shaving heat pumps

    International Nuclear Information System (INIS)

    Zhao, Xiling; Fu, Lin; Wang, Xiaoyin; Sun, Tao; Wang, Jingyi; Zhang, Shigang

    2017-01-01

    Highlights: • A flue gas recovery system with distributed peak-shaving heat pumps is proposed. • The system can improve network transmission and distribution capacity. • The system is advantageous in energy saving, emission reduction and economic benefits. - Abstract: District heating systems use distributed heat pump peak-shaving technology to adjust heat in secondary networks of substations. This technology simultaneously adjusts the heat of the secondary network and reduces the return-water temperature of the primary network by using the heat pump principle. When optimized, low temperature return-water is able to recycle more waste heat, thereby further improving the heating efficiency of the system. This paper introduces a flue gas recovery system for a natural gas combined heat and power plant with distributed peak-shaving heat pumps. A pilot system comprising a set of two 9F gas-steam combined cycle-back pressure heating units was used to analyse the system configuration and key parameters. The proposed system improved the network transmission and distribution capacity, increased heating capacity, and reduced heating energy consumption without compromising heating safety issues. As such, the proposed system is advantageous in terms of energy saving, emission reduction, and economic benefits.

  12. Drilling unit

    Energy Technology Data Exchange (ETDEWEB)

    Umanchik, N P; Demin, A V; Khrustalev, N N; Linnik, G N; Lovchev, S V; Rozin, M M; Sidorov, R V; Sokolov, S I; Tsaregradskiy, Yu P

    1981-01-01

    A drilling unit is proposed which includes a hydraulic lifter, hydraulic multiple-cylinder pump with valve distribution and sectional drilling pump with separators of the working and flushing fluid. In order to reduce metal consumption and the overall dimensions of the drilling unit, the working cavity of each cylinder of the hydraulic multiple-cylinder pump is equipped with suction and injection valves and is hydraulically connected to the working cavity by one of the sections of the drilling pump.

  13. Experimental study of enhancing heating performance of the air-source heat pump by using a novel heat recovery device designed for reusing the energy of the compressor shell

    International Nuclear Information System (INIS)

    Huang, Bi; Jian, Qifei; Luo, Lizhong; Zhao, Jing

    2017-01-01

    Highlights: • A novel heat recovery device was designed and tested. • Aiming at avoiding liquid slugging in cold areas. • Recovery of the waste energy of compressor housing. • Refrigerant is heated with the energy recovered before it is sucked into the compressor. • Requires no extra power while the recovery system is operating. - Abstract: A novel heat recovery device designed to recover the heat that is released from the outer surface of heat pump compressors, and to enhance the performance of heat pumps in cold areas was made and tested in this study. The novel heat recovery device consists of three fundamental units: a heat absorption unit, a heat emission unit and heat pipes. An amount of work focused on recovering the heat of compressors through oil system, but few studies concentrated on the housing. The main advantage of the heat recovery device is no need for extra energy consumption for its only driving force is the temperature difference between the compressor shell and the working fluid inside the suction line. The experimental results were obtained from a series of tests with a R410A air-source heat pump. Effects of the device are analyzed with respect of the suction temperature, temperature distribution among the housing, input power and exergy destruction. Moreover, the impact on the heating capacity is also discussed. Further, direction for improvement is also given based on the analysis.

  14. Convective heat transfer

    CERN Document Server

    Kakac, Sadik; Pramuanjaroenkij, Anchasa

    2014-01-01

    Intended for readers who have taken a basic heat transfer course and have a basic knowledge of thermodynamics, heat transfer, fluid mechanics, and differential equations, Convective Heat Transfer, Third Edition provides an overview of phenomenological convective heat transfer. This book combines applications of engineering with the basic concepts of convection. It offers a clear and balanced presentation of essential topics using both traditional and numerical methods. The text addresses emerging science and technology matters, and highlights biomedical applications and energy technologies. What’s New in the Third Edition: Includes updated chapters and two new chapters on heat transfer in microchannels and heat transfer with nanofluids Expands problem sets and introduces new correlations and solved examples Provides more coverage of numerical/computer methods The third edition details the new research areas of heat transfer in microchannels and the enhancement of convective heat transfer with nanofluids....

  15. The secure heating reactor

    International Nuclear Information System (INIS)

    Pind, C.

    1987-01-01

    The SECURE heating reactor was designed by ASEA-ATOM as a realistic alternative for district heating in urban areas and for supplying heat to process industries. SECURE has unique safety characteristics, that are based on fundamental laws of physics. The safety does not depend on active components or operator intervention for shutdown and cooling of the reactor. The inherent safety characteristics of the plant cannot be affected by operator errors. Due to its very low environment impact, it can be sited close to heat consumers. The SECURE heating reactor has been shown to be competitive in comparison with other alternatives for heating Helsinki and Seoul. The SECURE heating reactor forms a basis for the power-producing SECURE-P reactor known as PIUS (Process Inherent Ultimate Safety), which is based on the same inherent safety principles. The thermohydraulic function and transient response have been demonstrated in a large electrically heated loop at the ASEA-ATOM laboratories

  16. Effective geothermal heat

    International Nuclear Information System (INIS)

    Abelsen, Atle

    2006-01-01

    Scandinavia's currently largest geothermal heating project: the New Ahus hospital, is briefly presented. 300-400 wells on a field outside the hospital are constructed to store energy for both heating and cooling purposes

  17. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Be Prepared Safe Citizen Day Organize Important Medical Information ER Checklists Preparing for Emergencies Be ready to ... anyone can be affected. Here you will find information about heat cramps and heat stroke and exhaustion. ...

  18. Paleoclassical electron heat transport

    International Nuclear Information System (INIS)

    Callen, J.D.

    2005-01-01

    Radial electron heat transport in low collisionality, magnetically-confined toroidal plasmas is shown to result from paleoclassical Coulomb collision processes (parallel electron heat conduction and magnetic field diffusion). In such plasmas the electron temperature equilibrates along magnetic field lines a long length L, which is the minimum of the electron collision length and a maximum effective half length of helical field lines. Thus, the diffusing field lines induce a radial electron heat diffusivity M ≅ L/(πR 0q ) ∼ 10 >> 1 times the magnetic field diffusivity η/μ 0 ≅ ν e (c/ω p ) 2 . The paleoclassical electron heat flux model provides interpretations for many features of 'anomalous' electron heat transport: magnitude and radial profile of electron heat diffusivity (in tokamaks, STs, and RFPs), Alcator scaling in high density plasmas, transport barriers around low order rational surfaces and near a separatrix, and a natural heat pinch (or minimum temperature gradient) heat flux form. (author)

  19. Survey of residential heat pump owner experience in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Unsoy, J

    1985-11-11

    Heat pump owners in 7 Canadian cities were surveyed to establish installation costs, repair costs and frequencies, and customer satisfaction with heat pump systems as a function of region, installing contractor, manufacturer, model, year of installation and system type. The following summarizes the major findings of the study. Most Canadian heat pumps are retrofit installations in existing homes. The majority of these heat pumps have either supplemented or replaced an oil furnace. The average age of heat pumps is 2.5 years. The median size of heat pumps installed is 2.5 tons. The three most popular brands by order of prevalence are York, Carrier and General Electric. Only about one-fifth of heat pump owners have purchased service contracts. Two-thirds of the heat pumps have never needed repairs. Eighty-three percent of heat pump owners have never incurred any repair costs; and of those that have, about half spent $100 or less. The most frequent repair problems are refrigerant leaks followed by relays and controls. Corrective actions average about 0.3 per unit year. The owners' evaluation of comfort from their heat pump is generally favourable. About 12% of the owners find the outdoor unit noisy and 10% feel maintenance costs are at a disadvantage. Overall, only 7% of heat pump owners indicated that they would not install a heat pump in their next house. Most heat pump owners are satisfied with their heat pump brand and installer. Owners with systems installed in newer homes are more satisfied with their heat pumps than those who have installed heat pumps in older homes. 3 figs., 93 tabs.

  20. Regenerative heat sources for heating networks

    International Nuclear Information System (INIS)

    Huenges, Ernst; Sperber, Evelyn; Eggers, Jan-Bleicke; Noll, Florian; Kallert, Anna Maria; Reuss, Manfred

    2015-01-01

    The ambitious goal, the German Federal Government has set itself, to reduce the emissions of greenhouse gases by 80% to 95% by the year 2050. As there are currently more than half of German energy consumption for the production of heat is required, big contributions to climate protection can be expected from this area if more renewable heat sources are used. Renewable heat sources such as bioenergy, solar thermal and geothermal energy in particular can be provided as compared to fossil fuels with significantly lower specific CO 2 emissions. Objectives in the heating market and scenarios for the transformation of the heat sector have been elaborated in the BMU Lead Study 2011. The main pillar of this scenario is the reduction of final energy consumption for heat by the energy-efficient renovation of existing buildings and further increasing demands on the energetic quality of new buildings. To cover the remaining energy demand, a focus is on the expansion of heating networks based on renewable energies. [de

  1. Ion cyclotron resonance heating

    International Nuclear Information System (INIS)

    Tajima, T.

    1982-01-01

    Ion cyclotron resonance heating of plasmas in tokamak and EBT configurations has been studied using 1-2/2 and 2-1/2 dimensional fully self-consistent electromagnetic particle codes. We have tested two major antenna configurations; we have also compared heating efficiencies for one and two ion species plasmas. We model a tokamak plasma with a uniform poloidal field and 1/R toroidal field on a particular q surface. Ion cyclotron waves are excited on the low field side by antennas parallel either to the poloidal direction or to the toroidal direction with different phase velocities. In 2D, minority ion heating (vsub(perpendicular)) and electron heating (vsub(parallel),vsub(perpendicular)) are observed. The exponential electron heating seems due to the decay instability. The minority heating is consistent with mode conversion of fast Alfven waves and heating by electrostatic ion cyclotron modes. Minority heating is stronger with a poloidal antenna. The strong electron heating is accompanied by toroidal current generation. In 1D, no thermal instability was observed and only strong minority heating resulted. For an EBT plasma we model it by a multiple mirror. We have tested heating efficiency with various minority concentrations, temperatures, mirror ratios, and phase velocities. In this geometry we have beach or inverse beach heating associated with the mode conversion layer perpendicular to the toroidal field. No appreciable electron heating is observed. Heating of ions is linear in time. For both tokamak and EBT slight majority heating above the collisional rate is observed due to the second harmonic heating. (author)

  2. Comparison of LCA results of low temperature heat plant using electric heat pump, absorption heat pump and gas-fired boiler

    International Nuclear Information System (INIS)

    Nitkiewicz, Anna; Sekret, Robert

    2014-01-01

    Highlights: • Usage of geothermal heat pump can bring environmental benefits. • The lowest environmental impact for whole life cycle is obtained for absorption heat pump. • The value of heat pump COP has a significant influence on environmental impact. • In case of coal based power generation the damage to human health is significant. - Abstract: This study compares the life cycle impacts of three heating plant systems which differ in their source of energy and the type of system. The following heating systems are considered: electric water-water heat pump, absorption water-water heat pump and natural gas fired boiler. The heat source for heat pump systems is low temperature geothermal source with temperature below 20 °C and spontaneous outflow 24 m 3 /h. It is assumed that the heat pumps and boiler are working in monovalent system. The analysis was carried out for heat networks temperature characteristic at 50/40 °C which is changing with outdoor temperature during heating season. The environmental life cycle impact is evaluated within life cycle assessment methodological framework. The method used for life cycle assessment is eco-indicator ‘99. The functional unit is defined as heating plant system with given amount of heat to be delivered to meet local heat demand in assumed average season. The data describing heating plant system is derived from literature and energy analysis of these systems. The data describing the preceding life cycle phases: extraction of raw materials and fuels, production of heating devices and their transportation is taken from Ecoinvent 2.0 life cycle inventory database. The results were analyzed on three levels of indicators: single score indicator, damage category indicators and impact category indicator. The indicators were calculated for characterization, normalization and weighting phases as well. SimaPro 7.3.2 is the software used to model the systems’ life cycle. The study shows that heating plants using a low

  3. Heat roadmap China

    DEFF Research Database (Denmark)

    Xiong, Weiming; Wang, Yu; Mathiesen, Brian Vad

    2015-01-01

    District heating is regarded as a key element of energy saving actions in the Chinese national energy strategy, while space heating in China is currently still dominated by coal boilers. However, there is no existing quantitative study to analyse the future heat strategy for China. Therefore...

  4. Heat Recovery System

    Science.gov (United States)

    1984-01-01

    Ball Metal's design of ducting and controls for series of roof top heat exchangers was inspired by Tech Briefs. Heat exchangers are installed on eight press and coating lines used to decorate sheet metal. The heat recovery system provides an estimated energy savings of more than $250,000 per year.

  5. Solar heating pipe

    Energy Technology Data Exchange (ETDEWEB)

    Hinson-Rider, G.

    1977-10-04

    A fluid carrying pipe is described having an integral transparent portion formed into a longitudinally extending cylindrical lens that focuses solar heat rays to a focal axis within the volume of the pipe. The pipe on the side opposite the lens has a heat ray absorbent coating for absorbing heat from light rays that pass through the focal axis.

  6. Designing heat exchangers for process heat reactors

    International Nuclear Information System (INIS)

    Quade, R.N.

    1980-01-01

    A brief account is given of the IAEA specialist meeting on process heat applications technology held in Julich, November 1979. The main emphasis was on high temperature heat exchange. Papers were presented covering design requirements, design construction and prefabrication testing, and selected problems. Primary discussion centered around mechanical design, materials requirements, and structural analysis methods and limits. It appears that high temperature heat exchanges design to nuclear standards, is under extensive development but will require a lengthy concerted effort before becoming a commercial reality. (author)

  7. Necessity for usage of geothermal heat pump

    International Nuclear Information System (INIS)

    Dimitrov, Konstantin; Armenski, Slave; Gacevski, Marijan

    2004-01-01

    Every day we are witnesses of constantly rapid increase of consumption of Electric energy in R. of Macedonia as so as in the other countries in all the world. This rapid increase of consumption of Electric energy independent of a lot of electrical units, which are applying in human life like: homes, administration and publication objects, as well as in industry. All of this conditions make us to thinking how is possible more rational consumption of electric energy in all areas in human life. One of the possible manners to reduce the consumption of electrical energy for heating and cooling is to use geothermal heat pumps. In this paper will be proposed geothermal heat pump, which is going to use the heat of earth by vertical and horizontal cupper pipe heat exchanger with data from-GHP (Geothermal Heat Pump) NORDIC, factory in Canada. Also, it will be examined all parameters and done comparison with already existing ones. It is analyzed comparison of GHP with other energy units and what it means for rational consumption of electric energy, economic saving and ecology saving. (Author)

  8. Dual-stroke heat pump field performance

    Science.gov (United States)

    Veyo, S. E.

    1984-11-01

    Two nearly identical proprototype systems, each employing a unique dual-stroke compressor, were built and tested. One was installed in an occupied residence in Jeannette, Pa. It has provided the heating and cooling required from that time to the present. The system has functioned without failure of any prototypical advanced components, although early field experience did suffer from deficiencies in the software for the breadboard micro processor control system. Analysis of field performance data indicates a heating performance factor (HSPF) of 8.13 Stu/Wa, and a cooling energy efficiency (SEER) of 8.35 Scu/Wh. Data indicate that the beat pump is oversized for the test house since the observed lower balance point is 3 F whereas 17 F La optimum. Oversizing coupled with the use of resistance heat ot maintain delivered air temperature warmer than 90 F results in the consumption of more resistance heat than expected, more unit cycling, and therefore lower than expected energy efficiency. Our analysis indicates that with optimal mixing the dual stroke heat pump will yield as HSFF 30% better than a single capacity heat pump representative of high efficiency units in the market place today for the observed weather profile.

  9. Sensitivity of energy and exergy performances of heating and cooling systems to auxiliary components

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk; Shukuya, Masanori; Olesen, Bjarne W.

    2017-01-01

    . Different forms of energy (electricity and heat) are used in heating and cooling systems, and therefore, a holistic approach to system design and analysis is needed. In particular, distribution systems use electricity as a direct input to pumps and fans, and to other components. Therefore, exergy concept......Heating and cooling systems in buildings consist of three main subsystems: heating/cooling plant, distribution system, and indoor terminal unit. The choice of indoor terminal unit determines the characteristics of the distribution system and the heating and cooling plants that can be used...... should be used in design and analysis of the whole heating and cooling systems, in addition to the energy analysis. In this study, water-based (floor heating and cooling, and radiator heating) and air-based (air heating and cooling) heating and cooling systems were compared in terms of their energy use...

  10. 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...... 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......C. Due to the ice problem mechanical ventilation systems with heat recovery are often installed with an extra preheating system reducing the energy saving potential significantly. New designs of high efficient heat recovery units capable of continuously defrosting the ice without using extra energy...

  11. Arrangement to reduce the failure frequency of heat condensate pipes

    International Nuclear Information System (INIS)

    Liskow, E.; Apelt, W.; Krause, W.; Meisel, L.

    1988-01-01

    The arrangement of throttling devices in heat condensate pipes of NPP with WWER-440 type reactors aims at reducing their failure frequency, ensuring an energetically favourable operation, and enhancing the availability and safety of NPP units

  12. The effect of heat generation in inclined slats on the natural convective heat transfer from an isothermal heated vertical plate

    International Nuclear Information System (INIS)

    Oosthuizen, P.H.; Sun, L.; Naylor, D.

    2003-01-01

    Natural convective heat transfer from a wide heated vertical isothermal plate with adiabatic surfaces above and below the heated surface has been considered. There are a series of equally spaced vertical thin, flat surfaces (termed 'slats') near the heated surface, these surfaces being, in general, inclined to the heated surface. There is, in general, a uniform heat generation in the slats. The slats are pivoted about their centre-point and thus as their angle is changed, the distance of the tip of the slat from the plate changes. The situation considered is an approximate model of a window with a vertical blind, the particular case where the window is hotter than the room air being considered. The heat generation in the slats in this situation is the result of solar radiation passing through the window and falling on and being absorbed by the slats of the blind. The flow has been assumed to be laminar and steady. Fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces. The governing equations have been written in dimensionless form and the resulting dimensionless equations have been solved using a commercial finite-element package. The solution has the following parameters: (1) the Rayleigh number (2) the Prandtl number (3) the dimensionless heat generation rate in the slats per unit frontal area (4) the dimensionless distance of the slat center point (the pivot point) from the surface (5) the dimensionless slat size (6) the dimensionless slat spacing (7) the angle of inclination of the slats. Because of the application that motivated the study, results have only been obtained for a Prandtl number of 0.7. The effect of the other dimensionless variables on the mean dimensionless heat transfer rate from the heated vertical surface has been examined. (author)

  13. The increase performance BMF-14 calcination unit

    International Nuclear Information System (INIS)

    Triyono

    2013-01-01

    The heating element of performance increase BMF-14 calcination unit has been installed. The activity includes: installation and function test heating element step by step. The main component includes: kanthal heating element type with size long 58,2 cm diameter 0,9 cm slot total 28, flexible cable resists heat 30 Amperes, band cable heat resists and flexible clamp. The heating elements installation includes from 3 groups and every groups have 4 heating elements to connectly series. Every group connecting to every phase RST and neutral for getting electric voltage 380 Volts follow contact relay 3 phases to controlling by digital temperature control. The resulting installation of heating element in the BMF-14 calcination unit showed that: BMF-14 calcination unit can be again of the setting temperature step by step. In the step I get optimal temperature 560 °C test time 1068 minutes with rate velocity heat 0 to 18,0 °C/minutes with current between 5,8 to 6,4 Amperes voltage 103 to 123 Volts (phase R and T). In the step II gets optimal temperature 600 °C test time 265 minutes getting rate velocity heat 0 to 40,3 °C/minutes with current 3,8 to 8,5 Amperes voltage 76 to 142 Volts (phase RST). In the step III gets optimal temperature 1000 °C test time 107 minutes getting rate velocity heat 0 to 53,5 °C/minutes with current 9,7 to 12,5 Amperes voltage 215 to 225 Volts (phase RST). (author)

  14. Condensation heat transfer in plate heat exchangers

    International Nuclear Information System (INIS)

    Panchal, C.B.

    1985-01-01

    An Alfa-Laval plate heat exchanger, previously tested as an evaporator, was retested as a condenser. Two series of tests with different chevron-angle plates were carried out using ammonia as a working fluid. The overall heat-transfer coefficient and pressure drop were measured, and the effects of operating parameters were determined. The experimental data were compared with theoretical predictions. In the analysis, a gravity-controlled condensation process was modeled theoretically, and the overall performance was calculated. The analysis shows that the overall heat-transfer coefficient can be predicted with an average uncertainty of about 10%. It is, however, important to consider the interfacial shear stress, because the effective friction factor is high for flow in plate heat exchangers

  15. Single Electrode Heat Effects

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Broers, G. H. J.

    1977-01-01

    The heat evolution at a single irreversibly working electrode is treated onthe basis of the Brønsted heat principle. The resulting equation is analogous to the expression for the total heat evolution in a galvanic cellwith the exception that –DeltaS is substituted by the Peltier entropy, Delta......SP, of theelectrode reaction. eta is the overvoltage at the electrode. This equation is appliedto a high temperature carbonate fuel cell. It is shown that the Peltier entropyterm by far exceeds the heat production due to the irreversible losses, and thatthe main part of heat evolved at the cathode is reabsorbed...

  16. Introduction to heat transfer

    International Nuclear Information System (INIS)

    Weisman, J.

    1983-01-01

    Heat may be defined as that form of energy which spontaneously flows between two bodies, or two regions of a body, by virtue of a temperature difference. The second law of thermodynamics tells us that we cannot have heat flow from a low temperature to high temperature without doing work. Heat flows spontaneously from a high temperature to a low temperature region. Thermodynamics, which is concerned with equilibrium states, cannot tell us anything about the rate of heat flow in the presence of a finite temperature difference. It is to the discipline of heat transfer to which we must turn for this answer

  17. Heat and mass transfer in buildings

    International Nuclear Information System (INIS)

    Kristoffersen, Astrid Rusaas

    2005-01-01

    ceiling heating system (room without ventilation). The surplus is convective heat flux (about 20-25%). On the other hand, a lower water temperature can be exploited in the pipes obtaining the desired ceiling surface temperature due to the less strict functional requirements of materials for ceilings. The ceiling heating system was simulated with thin gypsum board layers covering the water pipes and the heat emission plate. Reducing the thickness of the gypsum board layer from 13 mm to 6 mm increased the heat flux from the ceiling by 20 %. Low tmperature heating systems heat the construction and the heat capacity of the construction is a challenge when it comes to designing a control strategy for the system. The fourth paper titled ''Control and energy metering in low temperature heating systems'' presented a new approach of temperature control and energy metering in LTH systems. The required heat is supplied in terms of energy pulses by intrmittent operation of the circulation pump or a motorized valve in the floor system. The temperature stability is demonstrated by measurements in a single-family house. The control unit calculated the heat demand from external variable basically represented by the ambient air temperature. The parameters necessary for temperature control can be extracted when the heat transfer coefficient and the heat capacity of the floor construction are known. Furthermore, the control strategy opens for energy metering in LTH systems by means of the parameters heat carrier temperature and the duty cycle. The method is demonstrated to be at least accurate within +1-5%. (Author)

  18. Heat Roadmap Europe 2

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg

    Many strategies have already been proposed for the decarbonisation of the EU energy system by the year 2050. These typically focus on the expansion of renewable energy in the electricity sector and subsequently, electrifying both the heat and transport sectors as much as possible. In these strate......Many strategies have already been proposed for the decarbonisation of the EU energy system by the year 2050. These typically focus on the expansion of renewable energy in the electricity sector and subsequently, electrifying both the heat and transport sectors as much as possible....... In these strategies, the role of district heating has never been fully explored system, nor have the benefits of district heating been quantified at the EU level. This study combines the mapping of local heat demands and local heat supplies across the EU27. Using this local knowledge, new district heating potentials...... are identified and then, the EU27 energy system is modelled to investigate the impact of district heating. The results indicate that a combination of heat savings, district heating in urban areas, and individual heat pumps in rural areas will enable the EU27 to reach its greenhouse gas emission targets by 2050...

  19. Mountain Plains Learning Experience Guide: Heating, Refrigeration, & Air Conditioning.

    Science.gov (United States)

    Carey, John

    This Heating, Refrigeration, and Air Conditioning course is comprised of eleven individualized units: (1) Refrigeration Tools, Materials, and Refrigerant; (2) Basic Heating and Air Conditioning; (3) Sealed System Repairs; (4) Basic Refrigeration Systems; (5) Compression Systems and Compressors; (6) Refrigeration Controls; (7) Electric Circuit…

  20. Impact of water hardness on energy consumption of geyser heating ...

    African Journals Online (AJOL)

    Therefore, the Eskom Research, Testing, and Development Business Unit embarked on a study to examine total water hardness as a chemical parameter that may impact the power consumption of electrical geyser heating elements. An accelerated scaling method was developed to lime-scale the geyser heating elements ...