WorldWideScience

Sample records for air treatment heating

  1. Enhancing the crystalline degree of carbon nanotubes by acid treatment, air oxidization and heat treatment

    Institute of Scientific and Technical Information of China (English)

    Chensha Li; Baoyou Zhang; Xingjuan Chen; Xiaoqing Hu; Ji Liang

    2005-01-01

    Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperature heat-treatment elevates the crystalline degree of carbon nanotubes. Acid treatment removes parts of amorphous carbonaceous matter through its oxidization effect.Air oxidization disperses carbon nanotubes and amorphous carbonaceous matter. The treatment of combining acid treatment with heat-treatment further elevates the crystalline degree of carbon nanotubes comparing with acid treatment or heat-treatment. The combination of the three treatments creates the thorough effects of enhancing the crystalline degree of carbon nanotubes.

  2. Effect of Combustion Air Pre-Heating In Carbon Monoxide Emission in Diesel Fired Heat Treatment Furnace

    Directory of Open Access Journals (Sweden)

    E B Muhammed Shafi,

    2015-09-01

    Full Text Available This paper describes the effect of combustion air pre- heating in Diesel fired heat Treatment Furnace. The main heat treatment processes are Normalizing, Tempering, Hardening, Annealing, Solution Annealing and Stress Relieving. The emission of carbon monoxide is measured with combustion air pre-heating and without preheating. The results are then compared and it is found that the emission of CO is reduced by 29.12%. With the Combustion air pre-heating a considerable reduction in Specific Furnace Fuel Consumption (SFFC is obtained. The test was caaried out at Peekay Steels Casting (P ltd, Nallalam, Calicut.

  3. Laser heat treatment of air plasma sprayed NiCrAlY overlay coatings

    International Nuclear Information System (INIS)

    The paper presents the effect of laser treatment upon structure, phase composition, thermophysical and operational properties of air plasma sprayed NiCrAlY overlay coatings on heat resistant nickel base alloy. Microstructural changes and changes in phase composition of laser remelted coatings reduce the effectiveness as thermal barriers and lower corrosion resistance but higher the resistance to thermal cycling. (author)

  4. Heat treatment's effects on hydroxyapatite powders in water vapor and air atmosphere

    Science.gov (United States)

    Karabulut, A.; Baştan, F. E.; Erdoǧan, G.; Üstel, F.

    2015-03-01

    Hydroxyapatite (HA; Ca10(PO4)6(OH)2) is the main chemical constituent of bone tissue (~70%) as well as HA which is a calcium phosphate based ceramic material forms inorganic tissue of bone and tooth as hard tissues is used in production of prosthesis for synthetic bone, fractured and broken bone restoration, coating of metallic biomaterials and dental applications because of its bio compatibility. It is known that Hydroxyapatite decomposes with high heat energy after heat treatment. Therefore hydroxyapatite powders that heated in water vapor will less decomposed phases and lower amorphous phase content than in air atmosphere. In this study high purity hydroxyapatite powders were heat treated with open atmosphere furnace and water vapor atmosphere with 900, 1000, 1200 °C. Morphology of same powder size used in this process by SEM analyzed. Chemical structures of synthesized coatings have been examined by XRD. The determination of particle size and morphological structure of has been characterized by Particle Sizer, and SEM analysis, respectively. Weight change of sample was recorded by thermogravimetric analysis (TGA) during heating and cooling.

  5. Simple approach to carboxyl-rich materials through low-temperature heat treatment of hydrothermal carbon in air

    International Nuclear Information System (INIS)

    It was found that a large number of oxygen-containing functional groups (OFGs) could be created on the surface of hydrothermal carbon (HTC) by simply heating at lower temperature in air during the course of our preliminary experiments which focused on oxidation pre-treatment of pristine HTC for the purpose of grafting functionalization. Especially carboxyl groups on HTC would increase significantly, from 0.53 to 3.70 mmol/g after heat treatment at 300 deg. C. So, effects of heat-treatment on the OFGs on the carbon microsphere were deeply studied to confirm and explain the findings. Experiments involving different materials (HTC, activated carbon and glucose) were performed under varying conditions (heating temperature and time, in air or in Ar atmosphere). A reaction mechanism for newly generating carboxyl groups on HTC surface during heat-treatment process was supposed based on the results from the sample characterization using Boehm titrations, infrared spectra, X-ray photoelectron spectroscopy, energy dispersive spectrometry and elemental analysis. In addition, the as heat-treated product has excellent sorption capability for Pb2+ and Cd2+ ions.

  6. Simple approach to carboxyl-rich materials through low-temperature heat treatment of hydrothermal carbon in air

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhen; Ma Lijian; Li Shuqiong; Geng Junxia; Song Qiang; Liu Jun; Wang Chunli; Wang Hang; Li Juan [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China); Qin Zhi [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li Shoujian, E-mail: sjli000616@scu.edu.cn [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China)

    2011-08-01

    It was found that a large number of oxygen-containing functional groups (OFGs) could be created on the surface of hydrothermal carbon (HTC) by simply heating at lower temperature in air during the course of our preliminary experiments which focused on oxidation pre-treatment of pristine HTC for the purpose of grafting functionalization. Especially carboxyl groups on HTC would increase significantly, from 0.53 to 3.70 mmol/g after heat treatment at 300 deg. C. So, effects of heat-treatment on the OFGs on the carbon microsphere were deeply studied to confirm and explain the findings. Experiments involving different materials (HTC, activated carbon and glucose) were performed under varying conditions (heating temperature and time, in air or in Ar atmosphere). A reaction mechanism for newly generating carboxyl groups on HTC surface during heat-treatment process was supposed based on the results from the sample characterization using Boehm titrations, infrared spectra, X-ray photoelectron spectroscopy, energy dispersive spectrometry and elemental analysis. In addition, the as heat-treated product has excellent sorption capability for Pb{sup 2+} and Cd{sup 2+} ions.

  7. Simple approach to carboxyl-rich materials through low-temperature heat treatment of hydrothermal carbon in air

    Science.gov (United States)

    Chen, Zhen; Ma, Lijian; Li, Shuqiong; Geng, Junxia; Song, Qiang; Liu, Jun; Wang, Chunli; Wang, Hang; Li, Juan; Qin, Zhi; Li, Shoujian

    2011-08-01

    It was found that a large number of oxygen-containing functional groups (OFGs) could be created on the surface of hydrothermal carbon (HTC) by simply heating at lower temperature in air during the course of our preliminary experiments which focused on oxidation pre-treatment of pristine HTC for the purpose of grafting functionalization. Especially carboxyl groups on HTC would increase significantly, from 0.53 to 3.70 mmol/g after heat treatment at 300 °C. So, effects of heat-treatment on the OFGs on the carbon microsphere were deeply studied to confirm and explain the findings. Experiments involving different materials (HTC, activated carbon and glucose) were performed under varying conditions (heating temperature and time, in air or in Ar atmosphere). A reaction mechanism for newly generating carboxyl groups on HTC surface during heat-treatment process was supposed based on the results from the sample characterization using Boehm titrations, infrared spectra, X-ray photoelectron spectroscopy, energy dispersive spectrometry and elemental analysis. In addition, the as heat-treated product has excellent sorption capability for Pb 2+ and Cd 2+ ions.

  8. Comparative study of denaturation of whey protein isolate (WPI) in convective air drying and isothermal heat treatment processes.

    Science.gov (United States)

    Haque, M Amdadul; Aldred, Peter; Chen, Jie; Barrow, Colin J; Adhikari, Benu

    2013-11-15

    The extent and nature of denaturation of whey protein isolate (WPI) in convective air drying environments was measured and analysed using single droplet drying. A custom-built, single droplet drying instrument was used for this purpose. Single droplets having 5±0.1μl volume (initial droplet diameter 1.5±0.1mm) containing 10% (w/v) WPI were dried at air temperatures of 45, 65 and 80°C for 600s at constant air velocity of 0.5m/s. The extent and nature of denaturation of WPI in isothermal heat treatment processes was measured at 65 and 80°C for 600s and compared with those obtained from convective air drying. The extent of denaturation of WPI in a high hydrostatic pressure environment (600MPa for 600s) was also determined. The results showed that at the end of 600s of convective drying at 65°C the denaturation of WPI was 68.3%, while it was only 10.8% during isothermal heat treatment at the same medium temperature. When the medium temperature was maintained at 80°C, the denaturation loss of WPI was 90.0% and 68.7% during isothermal heat treatment and convective drying, respectively. The bovine serum albumin (BSA) fraction of WPI was found to be more stable in the convective drying conditions than β-lactoglobulin and α-lactalbumin, especially at longer drying times. The extent of denaturation of WPI in convective air drying (65 and 80°C) and isotheral heat treatment (80°C) for 600s was found to be higher than its denaturation in a high hydrostatic pressure environment at ambient temperature (600MPa for 600s). PMID:23790837

  9. Effect of air heat treatment time on physical, chemical and DNA quality properties of strawberries fruit (cv. candonga

    Directory of Open Access Journals (Sweden)

    Mauro Musto

    2011-03-01

    Full Text Available Changes in quality properties of air heat-treated (45°C for 0, 2 and 4 h strawberries were investigated. As treatment time increased, most of physical, chemical and DNA quality properties decreased significantly. After 4 h, however, fruits showed the highest L* value, Hue angle, pH, SSC and total phenolic accumulation. The results of multiplex PCR assays showed two amplified fragments for all samples extracted from achenes. In thalamus, conversely, the number of amplified fragments decreased with time, indicating great degradation of DNA in this tissue.

  10. ASME N511-19XX, Standard for periodic in-service testing of nuclear air treatment, heating, ventilating and air conditioning systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    A draft version of the Standard is presented in this document. The Standard covers the requirements for periodic in-service testing of nuclear safety-related air treatment, heating, ventilating, and air conditioning systems in nuclear facilities. The Standard provides a basis for the development of test programs and does not include acceptance criteria, except in cases where the results of one test influence the performance of other tests. The Standard covers general inspection and test requirements, reference values, inspection and test requirements, generic tests, acceptance criteria, in-service test requirements, testing following an abnormal incident, corrective action requirements, and quality assurance. Mandatory appendices provide a visual inspection checklist and four test procedures. Non-mandatory appendices provide additional information and guidance on mounting frame pressure leak test procedure, corrective action, challenge gas substitute selection criteria, and test program development. 8 refs., 10 tabs.

  11. Sizing of solar supplemented liquid and air heating systems for the treatment of vanilla

    Energy Technology Data Exchange (ETDEWEB)

    Ratobison, R.; Daguenet, M. [Laboratoire de Thermodynamique et Energetique de l' Universite de Perpignan (France); Zeghmati, B. [Laboratoire de Metrologie des Interfaces Techniques, Belfort (France). IUT; Reddy, T.A. [Drexel University, Philadelphia, PA (United States). Dept. of Civil and Architectural Engineering

    1998-02-01

    We study three different configurations of solar supplemented systems for simultaneous production of hot air and hot water needed during the processing of vanilla. Correlations for the monthly solar fraction versus two dimensionless factors defined in terms of physical characteristics of the system have been developed. Not only have the various solar systems been evaluated against each other from a techno-economic point of view, but we have also proposed correlations for the optimal system which directly relate the mass of the product to be dried with the area of the solar collector. (author)

  12. Removal of uranium(VI) from aqueous solutions by carboxyl-rich hydrothermal carbon spheres through low-temperature heat treatment in air

    International Nuclear Information System (INIS)

    Carboxyl-rich hydrothermal carbon spheres were prepared by simply heating pristine hydrothermal carbon spheres (HCSs) at lower temperature in air, and the textural properties were characterized using Boehm titrations, scanning electron microscopy, Fourier transform infrared spectrometer (FT-IR) and elemental-analysis. The result of Boehm titrations indicated that the content of carboxyl groups on HCSs increased significantly from 0.53 to 3.81 mmol/g after heat-treatment at 300 deg C, which was also confirmed by FT-IR and EA qualitatively. The ability of heat-treated HCSs has been explored for the removal and recovery of uranium from aqueous solutions, and the influences of different experimental parameters, such as heat-treatment temperature, contact time and ionic strength, on adsorption were investigated. The U(VI) sorption capacity of HCSs increased from 55.0 to 179.95 mg/g after heat-treatment at 300 deg C for 5 h. Selective adsorption studies showed that the heat-treated HCSs could selectively remove U(VI), and the selectivity coefficients were improved after heat-treatment in the presence of co-existing ions, Na(I), Ni(II), Sr(II), Mn(II), Mg(II) and Zn(II). The adsorbent HCSs could be effectively regenerated by 0.05 mol/L HCl solution for the removal and recovery of U(VI). Complete removal (99.0 %) of U(VI) from 1.0 L industry wastewater containing 15.0 mg U(VI) ions was possible with 5.0 g heat-treated HCSs. In addition, a reaction mechanism for newly generating carboxyl groups on pristine HCSs surface during heat-treatment process and uranyl ion interaction with carboxyl-rich hydrothermal carbon spheres were also supposed. (author)

  13. 77 to 1200 K tensile properties of several wrought superalloys after long-term 1093 K heat treatment in air and vacuum

    Science.gov (United States)

    Whittenberger, J. D.

    1994-02-01

    The 77 to 1200 K tensile properties of approximately 1.3 mm thick wrought sheet Co-base Haynes alloy 188 and Ni-base Haynes alloy 230 and Inconel 617 have been measured after heat treatment in air and vacuum for periods up to 22,500 h at 1093 K. Significant changes in structure were produced by prior exposures, including precipitation of second phases and, in the case of heat treatment in air, oxide scale and surface-connected grain boundary pits/oxides, as deep as 50 to 70 µm, in all three superalloys. Due to the geometry of the experiment, the vacuum-exposed samples were protected from loss of volatile elements by evaporation; hence, such specimens were simply given 1093 K anneals in an innocuous environment, which produced very little surface attack. Compared to the properties of as-received alloys, prior exposure tended to reduce both the yield strength and ultimate tensile strength, with the greatest reductions at 77 and 298 K. The most dramatic effect of heat treatment was found in the low-temperature residual tensile elongation, where decreases from 40 to 5% at 77 K were found. Ductility is the only property that was found to have a consistent dependency on environment, with air exposure always yielding less tensile elongation than vacuum exposure.

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

    Science.gov (United States)

    Corbett, Robert J.; Miller, Barbara

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

  15. Heat Conduction of Air in Nano Spacing

    OpenAIRE

    Zhang Yao-Zhong; Zhao Bo; Huang Gai-Yan; Yang Zhi; Zhang Ya-Fei

    2009-01-01

    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 condu...

  16. Heat Conduction of Air in Nano Spacing.

    Science.gov (United States)

    Zhang, Yao-Zhong; Zhao, Bo; Huang, Gai-Yan; Yang, Zhi; Zhang, Ya-Fei

    2009-01-01

    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. PMID:20596486

  17. 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.

  18. Unitary air-to-air heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1977-07-01

    This technology evaluation covers commercially available unitary heat pumps ranging from nominal capacities of 1/sup 1///sub 2/ to 45 tons. The nominal COP of the heat pump models, selected as representative, vary from 2.4 to 2.9. Seasonal COPs for heat pump installations and single-family dwellings are reported to vary from 2.5 to 1.1, depending on climate. For cooling performance, the nominal EER's vary from 6.5 to 8.7. Representative part-load performance curves along with cost estimating and reliability data are provided to aid: (1) the systems design engineer to select suitably sized heat pumps based on life-cycle cost analyses, and (2) the computer programmer to develop a simulation code for heat pumps operating in an Integrated Community Energy System.

  19. HEATING AND AIR CONDITIONING EDUCATIONAL PROGRAM.

    Science.gov (United States)

    Lennox Industries, Inc., Marshalltown, IA.

    INCREASED MOTIVATION, INCREASED INITIAL COMPREHENSION, AND INCREASED RETENTION ARE THE PRIME GOALS OF THE LENNOX HEATING AND AIR CONDITIONING EDUCATION PROGRAM. IT IS A COMPLETE PROGRAM WITH ALL THE TEACHING TOOLS REQUIRED TO PRODUCE A KNOWLEDGEABLE HEATING AND AIR-CONDITIONING INSTALLER OR SERVICE MAN. THIS INSTRUCTIONAL PROGRAM IS DESIGNED…

  20. Air leakage in residential solar heating systems

    Science.gov (United States)

    Shingleton, J. G.; Cassel, D. E.; Overton, R. L.

    1981-02-01

    A series of computer simulations was performed to evaluate the effects of component air leakage on system thermal performance for a typical residential solar heating system, located in Madison, Wisconsin. Auxiliary energy required to supplement solar energy for space heating was determined using the TRNSYS computer program, for a range of air leakage rates at the solar collector and pebble bed storage unit. The effects of heat transfer and mass transfer between the solar equipment room and the heated building were investigated. The effect of reduced air infiltration into the building due to pressurized by the solar air heating system were determined. A simple method of estimating the effect of collector array air leakage on system thermal performance was evaluated, using the f CHART method.

  1. An important feature of air heat pump cycle: Heating capacity in line with heating load

    International Nuclear Information System (INIS)

    In the conventional vapor-compression heat pumps, the heating capacity and the heating load usually vary in opposite directions, which results in a mismatch of the heating capacity and the heating load at off-design conditions. Air (reversed Brayton) cycle is a potential substitute for the conventional vapor-compression cycles. This paper proved that in theory the air heat pump cycle can make the heating capacity in line with the heating load at a stable level of heating COP (coefficient of performance). A thermodynamic model for the air heat pump cycle with practical compressor and expander was developed. The optimal heating COP and the corresponding pressure ratio were derived from the model. Then the cycle performance was analytically expressed under the optimal COP conditions. The heating capacity under different operating conditions was found in line with the heating load. Comparisons between the air heat pump cycle and two typical vapor-compression heat pump cycles were numerically done for further verification. It also turned out that the energy efficiency of air heat pump is comparable to the transcritical CO2 heat pump, particularly at large temperature difference. - Highlights: • We developed a thermodynamic model for air heat pump cycle. • The optimal COP (coefficient of performance) was derived and the corresponding cycle performance was analyzed. • Comparison of air heat pump cycle and vapor-compression cycles was numerically done. • We proved air heat pump cycle can make heating capacity in line with heating load

  2. Evaluation of heat transfer enhancement in air-heating collectors

    Energy Technology Data Exchange (ETDEWEB)

    Mattox, D. L.

    1979-06-01

    The present research effort was initiated for the purpose of increasing the thermal efficiency of air heating solar collectors through identification and development of optimum design and operation criteria for solar absorber-to-air heat exchangers. Initially this effort took the form of a solar collector systems analysis to evaluate the impact of various techniques for enhancing the heat transfer between the absorber and air stream on overall thermal performance of the entire solar collector. This systems analysis resulted in the selection of solar collector designs providing ducted cooling air on the absorber shaded side as a base line. A transient heat transfer analysis of a complete solar air heating collector was used to demonstrate that an optimum absorber-to-air heat exchanger design could be provided with several interrupted fin configurations. Additional analyses were performed to establish that the maximum solar collector thermal performance to required pumping power was realized for a Reynolds number range of 1000 to 2000. This Reynolds number range was used to establish a theoretical design limit curve for maximum thermal performance versus required pumping power for all interrupted fin designs as published in the open literature. Heat and momentum transfer empirical relationships were defined for scaling the state-of-the-art high conductance fin designs identified from a compact configuration to the less compact designs needed for solar collectors.

  3. Heating, ventilation and air conditioning system modelling

    Energy Technology Data Exchange (ETDEWEB)

    Whalley, R.; Abdul-Ameer, A. [British University in Dubai (United Arab Emirates)

    2011-03-15

    Heating, ventilation and air conditioning modelling methods, for large scale, spatially dispersed systems are considered. Existing techniques are discussed and proposals for the application of novel analysis approaches are outlined. The use of distributed-lumped parameter procedures enabling the incorporation of the relatively concentrated and significantly dispersed, system element characteristics, is advocated. A dynamic model for a heating, ventilation and air conditioning system comprising inlet and exhaust fans, with air recirculation, heating/cooling and filtration units is presented. Pressure, airflow and temperature predictions within the system are computed following input, disturbance changes and purging operations. The generalised modelling advancements adopted and the applicability of the model for heating, ventilation and air conditioning system simulation, re-configuration and diagnostics is emphasised. The employment of the model for automatic, multivariable controller design purposes is commented upon. (author)

  4. Unitary water-to-air heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1977-10-01

    Performance and cost functions for nine unitary water-to-air heat pumps ranging in nominal size from /sup 1///sub 2/ to 26 tons are presented in mathematical form for easy use in heat pump computer simulations. COPs at nominal water source temperature of 60/sup 0/F range from 2.5 to 3.4 during the heating cycle; during the cooling cycle EERs range from 8.33 to 9.09 with 85/sup 0/F entering water source temperatures. The COP and EER values do not include water source pumping power or any energy requirements associated with a central heat source and heat rejection equipment.

  5. Improved Air-Treatment Canister

    Science.gov (United States)

    Boehm, A. M.

    1982-01-01

    Proposed air-treatment canister integrates a heater-in-tube water evaporator into canister header. Improved design prevents water from condensing and contaminating chemicals that regenerate the air. Heater is evenly spiraled about the inlet header on the canister. Evaporator is brazed to the header.

  6. Heating load, heating-load density and COP optimizations of an endoreversible air heat-pump

    International Nuclear Information System (INIS)

    The finite-time thermodynamic performance has been studied of an endoreversible air heat-pump with constant-temperature heat-reservoirs. The heating load, the coefficient of performance (COP), and the heating-load density, i.e. the ratio of heating load to the maximum specific volume in the cycle, are the optimization objectives. The analytical formulae relating the heating load and pressure-ratio, between the COP and pressure-ratio, as well as between the heating-load density and pressure-ratio are derived assuming heat resistance losses occur in the hot- and cold-side heat-exchangers. The influences of the effectiveness of the heat-exchangers and the heat-reservoir temperature-ratio on the heating load, the COP and the heating-load density are analyzed. The cycle performance optimizations are performed by searching the optimal distribution of heat conductance of the hot- and cold-side heat-exchangers for the fixed total heat-exchanger inventory. The influences of some design parameters, including heat-capacity rate of the working fluid, heat-reservoir temperature-ratio and heat-exchanger inventory on the optimal distribution of heat conductance, the maximum heating load and the maximum heating-load density are indicated by numerical examples. The different results obtained from the heating-load optimization and the heating-load density optimization are shown. The air heat-pump design, with heat-loading density optimization, leads to smaller size equipment

  7. Real heat recovery with air handling units

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-07-01

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

  8. Treatment of suspected heat illness.

    Science.gov (United States)

    Eichner, E R

    1998-06-01

    1. Despite advances in the art and science of fluid balance, exertional heat illness -- even life-threatening heat stroke -- remains a threat for some athletes today. 2. Risk factors for heat illness include: being unacclimatized, unfit, or hypohydrated; certain illnesses or drugs; not drinking in long events; and a fast finishing pace. 3. Heat cramps typically occur in conditioned athletes who compete for hours in the sun. They can be prevented by increasing dietary salt and staying hydrated. 4. Early diagnosis of heat exhaustion can be vital. Early warning signs include: flushed face, hyperventilation, headache, dizziness, nausea, tingling arms, piloerection, chilliness, incoordination, and confusion. 5. Pitfalls in the diagnosis of heat illness include: confusion preventing self-diagnosis; the lack of trained spotters; rectal temperature not taken promptly; the problem of "seek not, find not;" and the mimicry of heat illness. 6. Heat stroke is a medical emergency. Mainstays of therapy include: emergency on-site cooling; intravenous fluids; treating hypoglycemia as needed; intravenous diazepam for seizures or severe cramping or shivering; and hospitalizing if response is slow or atypical. 7. The best treatment is prevention. Tips to avoiding heat illness include: rely not on thirst; drink on schedule; favor sports drinks; monitor weight; watch urine; shun caffeine and alcohol; key on meals for fluids and salt; stay cool when you can; and know the early warning signs of heat illness. PMID:9694424

  9. Analyzis of exhaust air-source heat pump

    OpenAIRE

    Strautnikas, Jonas

    2014-01-01

    First there are heat losses calculations to find out needed amount of the energy for heating purposes. Then it is analized an exhaust air-source heat pump. Calculated annual electricity energy consumption and annual costs of the exhaust air-source heat pump. In the end it is compared two different heat pumps. Found out which (exhaust air-source or ground source) heat pump consumes less electricity energy consumption.

  10. Air reversing CO2 heat pumps

    OpenAIRE

    Andreassen, Hanne Elisabeth Bø

    2010-01-01

    CO2 is an environmentally friendly refrigerant that has a no global warming potential when used as refrigerant. The current refrigerants used for air conditioning in public transport are chemical components, and have a high global warming impact. The possibility of replacing the conventional refrigerants by CO2 is investigated for various parts of the transport sector. A possible CO2system for heating and cooling for public transport has been modeled and simulated. This system is a turntable ...

  11. CDC WONDER: Daily Air Temperatures and Heat Index

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Daily Air Temperature and Heat Index data available on CDC WONDER are county-level daily average air temperatures and heat index measures spanning the years...

  12. An analysing of heat treatment process planning

    OpenAIRE

    B. Smoljan

    2007-01-01

    Purpose: Process planning of heat treatment has been investigated. The established approach of heat treatingprocess planning is suitable for effective integration of heat treatment in computer added manufacturing.Design/methodology/approach: Process plan of heat treating process has been established based on fundamentalprocess planning principals. The heat treatment was treated in the same as other manufacture processes.Findings: The general approach for process planning of heat treatment pro...

  13. A heat treatment process optimization

    International Nuclear Information System (INIS)

    Taguch methodology is one of the most powerful techniques for improving product and manufacturing process quality at low cost. It is a strategical and practical method that aims to assist managers and industrial engineers to tackle manufacturing quality problems in a systematic and planned manner. The potential benefit of Taguch methodology lies in its ease of use, its emphasis on reducing variability to give more economical products and hence the accessibility to the engineering society for solving real life quality problems. This study applies Taguch methodology to optimize the process parameters of a purposed heat treatment process. The hardness of steel is generally a function not only of its composition, but rather of its heat treatment.The study investigates the effects of various heat treatment parameters, such as ramp rate of heating, normalizing holding time, ...etc, on the hardness of AS 4140, which is a measures of resistance to plastic deformation. The average hardness (HB) has improved by more than 15%. Both the analysis of means (ANOM) and single to noise ratio (S/N) have been carried out for determining the optimal condition of the process. The Scanning Electron Microscopy technique was used in this study to gain visual evidence of the quality and continuous improvement of the heat treated samples. (author)

  14. THERMAL ANALYSIS OF EARTH AIR HEAT EXCHANGER USING CFD

    OpenAIRE

    Vaibhav Madane; Meeta Vedpathak

    2015-01-01

    This project focuses on Earth Air Heat Exchanger which is reducing energy consumption in a building. The air is passing through the buried tubes and heat exchange takes place between air and surrounding soil. This equipment helps to reduce energy consumption of an air conditioning unit. This project analyses the thermal performance of earth air heat exchanger by using computational fluid dynamics modeling. The model is validated against experimental observations and investigations...

  15. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate... holding of a drug product. (c) Air filtration systems, including prefilters and particulate matter...

  16. Heat treatment of thermal barrier coatings

    International Nuclear Information System (INIS)

    Thermal barrier coatings (TBCs) with CoNiCrAlY bond-coat and 0.3 mm thick zirconia top-coat were air plasma sprayed (APS) onto a nickel-base super alloy, Hastelloy-X and 316L stainless substrates. The samples were heat treated at different temperatures. The resulting microstructural features and fracture surfaces of the zirconia top-coat were studied by optical and electron microscopies. Formation of spinels was observed close to the thermal grown oxide (TGO)/top-coat interface, and it was noticed that this layer became thicker during long heat treatments. Top-coat phase stability was assessed by X-ray diffraction, and it was observed that for long heat treatments the top-coat transformed up to 26% into monoclinic phase. Residual stresses and relative interfacial toughness are also important factors, which affect the life of the TBC. They were determined by the hole drill method and by Vickers indentation. The relative interfacial toughness between the top-coat and bond-coat increased with increasing temperature for nickel-base super alloy substrates whereas, for stainless steel based TBCs it increased only up to 650 deg. C and then decreased with increasing temperature. For long heat treatments, the nickel-base TBCs showed that the interface between top-coat and bond-coat deteriorated with extended exposure time

  17. Performance evaluation of an air-to-air heat pump coupled with temperate air-sources integrated into a dwelling

    OpenAIRE

    Filliard, Bruno; Guiavarch, Alain; Peuportier, Bruno

    2009-01-01

    An inverter-driven air-to-air heat pump model has been developped and implemented in the thermal simulation tool COMFIE, in order to compare the seasonal performance of a variable capacity air-to-air heat pump coupled with temperate air sources (crawlspace, attic, sunspace, heat recovery ventilation, earth-to-air heat exchanger) with the performance of a conventionally installed heat pump. The empirical model of the heat pump is presented in this paper, including full-load and part-load model...

  18. Experimental study on energy performance of clean air heat pump

    DEFF Research Database (Denmark)

    Fang, Lei; Nie, Jinzhe; Olesen, Bjarne W.

    2014-01-01

    to investigate its energy performance. Energy consumption of the prototype of CAHP was measured in laboratory at different climate conditions including mild-cold, mildhot and extremely hot and humid climates. The energy saving potential of the clean air heat pump compared to a conventional ventilation and air......An innovative clean air heat pump (CAHP) was designed and developed based on the air purification capacity of regenerative silica gel rotor. The clean air heat pump integrated air purification, dehumidification and cooling in one unit. A prototype of the clean air heat pump was developed......-conditioning system was calculated. The experimental results showed that the clean air heat pump saved substantial amount of energy compared to the conventional system. For example, the CAHP can save up to 59% of electricity in Copenhagen, up to 40% of electricity in Milan and up to 30% of electricity in Colombo...

  19. Parametric simulation and experimental analysis of earth air heat exchanger with solar air heating duct

    Directory of Open Access Journals (Sweden)

    Sanjeev Jakhar

    2016-06-01

    Full Text Available Earth air heat exchanger (EAHE systems are insufficient to meet the thermal comfort requirements in winter conditions. The low heating potential of such systems can be improved by integrating the system with solar air heating duct (SAHD. The aim of this paper is to present a model to estimate the heating potential for EAHE system with and without SAHD. The model is generated using TRNSYS 17 simulation tool and validated against experimental investigation on an experimental set-up in Ajmer, India. The experiment was done during the winter season, where the system was evaluated for different inlet flow velocities, length and depth of buried pipe. From the experimentation, it was observed that the depth of 3.7 m is sufficient for pipe burial and the 34 m length of pipe is sufficient to get optimum EAHE outlet temperature. It is also observed that increase in flow velocity results in drop in EAHE outlet temperature, while room temperature is found to increase for higher velocities (5 m/s. The COP of the system also increased up to 6.304 when assisted with solar air heating duct. The results obtained from the experiment data are in good agreement with simulated results within the variation of up to 7.9%.

  20. Refrigeration, Heating & Air Conditioning. Post Secondary Curriculum Guide.

    Science.gov (United States)

    Garrison, Joe C.; And Others

    This curriculum guide was designed for use in postsecondary refrigeration, heating and air conditioning education programs in Georgia. Its purpose is to provide for the development of entry level skills in refrigeration, heating, and air conditioning in the areas of air conditioning knowledge, theoretical structure, tool usage, diagnostic ability,…

  1. Model Based Diagnosis of an Air Source Heat Pump

    OpenAIRE

    Alfredsson, Sandra

    2011-01-01

    The purpose of a heat pump is to control the temperature of an enclosed space. This is done by using heat exchange with a heat source, for example water, air, or ground. In the air source heat pump that has been studied during this master thesis, a refrigerant exchanges heat with the outdoor air and with a water distribution system. The heat pump is controlled through the circuit containing the refrigerant and it is therefore crucial that this circuit is functional. To ensure this, a diagnosi...

  2. Heat Treatment Procedure Qualification for Steel Castings

    Energy Technology Data Exchange (ETDEWEB)

    Mariol Charles; Nicholas Deskevich; Vipin Varkey; Robert Voigt; Angela Wollenburg

    2004-04-29

    Heat treatment practices used by steel foundries have been carefully studied as part of comprehensive heat treatment procedure qualification development trials. These studies highlight the relationships between critical heat treatment process control parameters and heat treatment success. Foundry heat treatment trials to develop heat treatment procedure qualifications have shed light on the relationship between heat treatment theory and current practices. Furnace load time-temperature profiles in steel foundries exhibit significant differences depending on heat treatment equipment, furnace loading practice, and furnace maintenance. Time-temperature profiles of furnace control thermocouples can be very different from the time-temperature profiles observed at the center of casting loads in the furnace. Typical austenitization temperatures and holding times used by steel foundries far exceed what is required for transformation to austenite. Quenching and hardenability concepts were also investigated. Heat treatment procedure qualification (HTPQ) schema to demonstrate heat treatment success and to pre-qualify other alloys and section sizes requiring lesser hardenability have been developed. Tempering success is dependent on both tempering time and temperature. As such, furnace temperature uniformity and control of furnace loading during tempering is critical to obtain the desired mechanical properties. The ramp-up time in the furnace prior to the establishment of steady state heat treatment conditions contributes to the extent of heat treatment performed. This influence of ramp-up to temperature during tempering has been quantified.

  3. Heat Treatment Procedure Qualification -- Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Robert C. Voigt

    2004-10-15

    Heat treatment practices used by steel foundries have been carefully studied as part of comprehensive heat treatment procedure development trials. These studies highlight the relationships between critical heat treatment process control parameters and heat treatment success. Foundry heat treatment trials to develop heat treatment procedure qualification have shed light on the relationship between heat treatment theory and current practices. Furnace load time-temperature profiles in steel foundries exhibit significant differences depending on heat treatment equipment, furnace loading practice, and furnace maintenance. Time-temperature profiles of the furnace control thermocouples can be very different from the time-temperature profiles observed at the center of casting loads in the furnace. Typical austenitrization temperatures and holding times used by steel foundries far exceed what is required for transformation to austenite. Quenching and hardenability concepts were also investigated. Heat treatment procedure qualification (HTPQ) schema to demonstrate heat treatment success and to pre-qualify other alloys and section sizes requiring lesser hardenability have been developed. Tempering success is dependent on both tempering time and temperature. As such, furnace temperature uniformity and control of furnace loading during tempering is critical to obtain the desired mechanical properties. The ramp-up time in the furnace prior to the establishment of steady state heat treatment conditions contributes to the extent of heat treatment performed. This influence of ramp-up to temperature during tempering has been quantified.

  4. 29 CFR 1919.36 - Heat treatment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.36 Section 1919.36 Labor Regulations...) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.36 Heat treatment. (a) The annealing of wrought iron gear required by this part shall...

  5. 29 CFR 1919.80 - Heat treatment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.80 Section 1919.80 Labor Regulations...) GEAR CERTIFICATION Certification of Shore-Based Material Handling Devices § 1919.80 Heat treatment. (a) Wherever heat treatment of any loose gear is recommended by the manufacturer, it shall be carried out...

  6. Heat Waves, Urban Vegetation, and Air Pollution

    Science.gov (United States)

    Churkina, G.; Grote, R.; Butler, T. M.

    2014-12-01

    Fast-track programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase carbon storage, storm water control, provision of space for recreation, as well as poverty alleviation. Although these multiple benefits speak positively for urban greening programs, the programs do not take into account how close human and natural systems are coupled in urban areas. Elevated temperatures together with anthropogenic emissions of air and water pollutants distinguish the urban system. Urban and sub-urban vegetation responds to ambient changes and reacts with pollutants. Neglecting the existence of this coupling may lead to unforeseen drawbacks of urban greening programs. The potential for emissions from urban vegetation combined with anthropogenic emissions to produce ozone has long been recognized. This potential increases under rising temperatures. Here we investigate how global change induced heat waves affect emissions of volatile organic compounds (VOC) from urban vegetation and corresponding ground-level ozone levels. We also quantify other ecosystem services provided by urban vegetation (e.g., cooling and carbon storage) and their sensitivity to climate change. In this study we use Weather Research and Forecasting Model with coupled atmospheric chemistry (WRF-CHEM) to quantify these feedbacks in Berlin, Germany during the heat waves in 2003 and 2006. We highlight the importance of the vegetation for urban areas under changing climate and discuss associated tradeoffs.

  7. Distribution of air parameters in premises with heat release sources

    Directory of Open Access Journals (Sweden)

    G.M. Pozin

    2012-01-01

    Full Text Available The paper is devoted to control of air flows in premises with heat release sources. The modern numerical methods of heat and air exchange processes studies grounded on the equations of Navier – Stokes were utilized. The design schema of air exchange control that ensured heating of the lower zone of premise in the cold period of the year was accepted. The results of warm air processes numerical modeling in premises with heat sources placed above the level of the floor were presented. Using the inlet spray feeding schema inducing vibratory process, air temperature and velocity fields were given for increasing heat recovery effectiveness. For the first time air relative humidity distribution fields were obtained by a numerical method.

  8. Energy efficient air to air heat pump operating with R-1234yf

    OpenAIRE

    Mortada, Sorina; Clodic, Denis; Arzano-Daurelle, Christine

    2011-01-01

    Significant improvements in energy performance of air-to-air heat pumps are the major reason of their introduction in the late '90s for heating buildings in Japan and several European countries. They are installed in multi-dwelling units and in individual houses. Some of them are using variable speed compressors. European existing air-to-air heat pumps are not adapted for the low-energy building requirements. Their heating capacity is relatively higher than the heating demand and their energy...

  9. Dynamic Performance of a Residential Air-to-Air Heat Pump.

    Science.gov (United States)

    Kelly, George E.; Bean, John

    This publication is a study of the dynamic performance of a 5-ton air-to-air heat pump in a residence in Washington, D.C. The effect of part-load operation on the heat pump's cooling and heating coefficients of performance was determined. Discrepancies between measured performance and manufacturer-supplied performance data were found when the unit…

  10. 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…

  11. Air heating solar collectors and its applicability for room ventilation and heating

    International Nuclear Information System (INIS)

    This paper describes the results of the investigation the aim of which was to find new air heating solar collector constructions and easily to accessible materials which it is possible to use as absorbers. We tested the inflatable air heating solar collector construction. Inflatable solar collector gives good correlation with air heating degree and radiation (r=0.93). This type of collectors very sensitive to radiation changes, response time is only about 1 minute. Given type of air heating solar collectors is a good efficiency, the efficiency coefficient is Ș =0.63. Absorber materials (seed boxes made by polypropylene, black colored energy drink cans situated on steel-tinplate ) are tested for room heating and ventilating. Stationary air heating solar collectors for room heating are using in case, when sun radiation exceed 300 W/m2 , otherwise it is not effective or ambient air temperature is cooling room air. Collectors is recommended for room ventilation to reduce heat lost in cold weather. The collectors should be well insulated, especially if they are to be used in early spring, when ambient temperatures are low. These researches show air heating solar collectors applicability in room heating and ventilating, agricultural production drying at Latvia weather conditions Key words: solar collector, air heating, temperature, absorber

  12. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures, the...... dioxide air conditioning or heat pump systems and for intelligent controlling such systems....

  13. Novel development of heat treatment techniques for seed surface sterilisation

    OpenAIRE

    Borgen, Anders; Krebs, Niels; Langkjær, carsten

    2005-01-01

    Heat treatment to prevent seed borne diseases, e.g. in the form of hot water or warm humid air, will normally heat up the entire seed. Heat treatment of the seed embryo will always have a negative side-effect on seed vigour and the duration of several minutes are difficult to implement in seed plans treating huge volumes of seed. However, in the case of common bunt in wheat and similar diseases, where the inoculum is transmitted as fungal spores on the surface of the seed, an uniform and effi...

  14. POROSITY DEVELOPMENT DURING HEAT TREATMENT OF ALUMINUM-LITHIUM ALLOYS

    OpenAIRE

    Papazian, J.; J. Wagner; Rooney, W.

    1987-01-01

    The development of a sub-surface layer of porosity during heat treatment has been studied in a variety of Al-Li alloys. Pure binary Al-Li alloys and three commercial materials were heat treated in air, vacuum and hydrogen for various lengths of time. Subsequent metallographic sectioning and polishing revealed the presence of a band of pores in the near-surface region extending approximately 300 µm into the sample after a 16 h heat treatment. This band of porosity is thought to arise from a Ki...

  15. Analysis and application of variable conductance heat pipe air preheater

    Science.gov (United States)

    Shi, Chengming; Wang, Yang; Liao, Quan; Yang, Ying

    2011-09-01

    The heat transfer analysis of variable conductance heat pipe air preheater was carried out. The temperature transfer matrix was obtained for the air preheater that comprises several discrete heat transfer units with same or different heat transfer surface area in a parallel or counter flow mode. By using the temperature transfer matrix, the outlet fluid temperatures could be easily calculated for a given air preheater and inlet fluid temperatures. The active length of condenser in a variable conductance heat pipe is determined according to the flat interface model. With the same initial conditions, the comparisons between variable conductance heat-pipe air preheater and regular heat pipe air preheater has been analyzed and tested in terms of heat pipe wall temperature, heat transfer surface area and outlet fluid temperatures. Based on the real industrial applications, it has been confirmed that the variable conductance heat pipe air preheater has excellent performance of anti-corrosion and anti-ash-deposition especially at the variable working condition and the sulfur coal (5%-6% mass fraction of sulfur) condition.

  16. Effect of pre-storage heat treatment on enzymological changes in peach.

    Science.gov (United States)

    Bakshi, Parshant; Masoodi, F A

    2010-08-01

    Peach (Prunus persica (L.) Batsch) fruit was subjected to hot water and moist hot air treatment at varying temperatures. The activities of polyphenoloxidase (PPO) and polygalacturonase (PG) were monitored during storage for 0, 3 and 6 days. PPO activity decreased in all treatments during storage. This decrease was more in hot water treated fruits than in hot air. PPO activity decreased with the increase in treatment duration. However, the PG activity increased in heat treated fruits as well as control. This increase was more in mild heat treatments as compared to severe heat treatment. Both polyphenol and pectin contents decreased during storage in both heat treatments. PMID:23572672

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-09-01

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

  18. Air-to-air heat pumps in real-life use

    DEFF Research Database (Denmark)

    Gram-Hanssen, Kirsten; Christensen, Toke Haunstrup; Petersen, Poul Erik

    2012-01-01

    This paper deals with individual air-to-air heat pumps in Danish dwellings and summerhouses and the question of to what extent they actually deliver savings of energy consumption. Results show that 20% of the expected reduction of electricity consumption is converted into increased comfort in the...... homes, including extended heating areas, keeping a higher temperature and a longer heating season and using the heat pump for air conditioning. Data include electricity consumption in 185 households before and after installation of heat pumps together with survey results of 480 households. Furthermore...

  19. A solar air collector with integrated latent heat thermal storage

    Science.gov (United States)

    Charvat, Pavel; Ostry, Milan; Mauder, Tomas; Klimes, Lubomir

    2012-04-01

    Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM) was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data).

  20. A solar air collector with integrated latent heat thermal storage

    Directory of Open Access Journals (Sweden)

    Klimes Lubomir

    2012-04-01

    Full Text Available Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data.

  1. Efficient air-water heat pumps for high temperature lift residential heating, including oil migration aspects

    OpenAIRE

    Zehnder, Michele

    2004-01-01

    This thesis presents a system approach with the aim to develop improved concepts for small capacity, high temperature lift air-water heat pumps. These are intended to replace fuel fired heating systems in the residential sector, which leads to a major reduction of the local greenhouse gas emissions. Unfavorable temperature conditions set by the existing heat distribution systems and by the use of atmospheric air, as the only accessible heat source, have to be overcome. The proposed concepts a...

  2. Efficient air-water heat pumps for high temperature lift residential heating, including oil migration aspects

    OpenAIRE

    Zehnder, Michele; Favrat, Daniel

    2005-01-01

    This thesis presents a system approach with the aim to develop improved concepts for small capacity, high temperature lift air-water heat pumps. These are intended to replace fuel fired heating systems in the residential sector, which leads to a major reduction of the local greenhouse gas emissions. Unfavorable temperature conditions set by the existing heat distribution systems and by the use of atmospheric air, as the only accessible heat source, have to be overcome. The proposed concepts a...

  3. Air distribution and ventilation effectiveness in an occupied room heated by warm air

    DEFF Research Database (Denmark)

    Krajcik, Michal; Simone, Angela; Olesen, Bjarne W.

    2012-01-01

    environment. Contaminant removal effectiveness and air change efficiency were used to evaluate ventilation effectiveness. No significant risk of thermal discomfort due to vertical air temperature differences or draught was found. When the room was heated by warm air, buoyancy forces were important for......Air distribution, ventilation effectiveness and thermal environment were experimentally studied in a simulated room in a low-energy building heated and ventilated by warm air supplied by a mixing ventilation system. Measurements were performed for various positions of the air terminal devices and...... ventilation effectiveness at low air change rates. The effect of increasing air change on the ventilation effectiveness depended on the position of air terminal devices. Depending on the position of air terminal devices, the ventilation effectiveness varied between 0.4 and 1.2, where 1 is complete mixing...

  4. 29 CFR 1919.16 - Heat treatment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.16 Section 1919.16 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.16 Heat treatment. (a) All chains...

  5. A solar air collector with integrated latent heat thermal storage

    OpenAIRE

    Klimes Lubomir; Mauder Tomas; Ostry Milan; Charvat Pavel

    2012-01-01

    Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM) was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage...

  6. Applicability of sewage heat pump air-conditioning system

    Institute of Scientific and Technical Information of China (English)

    陈金华; 刘猛; 刘勇; 靳鸣; 陈洁

    2009-01-01

    A sewage heat pump system and its application based on a project in Chongqing,China,were discussed. Based on the sewage conditions,a feasibility analysis of the sewage heat pump air conditioning system was conducted. The theoretical and quantitative calculations indicate that sewage flux in the city sewage main pipe in the project can satisfy heat exchange requirements,and taking water from the pipes has relatively small influence on the pipe net in summer and winter. The sewage heat pump air-conditioning system can save 21.5% operating cost in one year,which is energy efficient and environmentally friendly.

  7. Solar Air Heaters with Thermal Heat Storages

    OpenAIRE

    Abhishek Saxena; Varun Goel

    2013-01-01

    Solar energy can be converted into different forms of energy, either to thermal energy or to electrical energy. Solar energy is converted directly into electrical power by photovoltaic modules, while solar collector converts solar energy into thermal energy. Solar collector works by absorbing the direct solar radiation and converting it into thermal energy, which can be stored in the form of sensible heat or latent heat or a combination of sensible and latent heats. A theoretical study has be...

  8. Advances in the heat treatment of steels

    International Nuclear Information System (INIS)

    A number of important recent advances in the processing of steels have resulted from the sophisticated uses of heat treatment to tailor the microstructure of the steels so that desirable properties are established. These new heat treatments often involve the tempering or annealing of the steel to accompish a partial or complete reversion from martensite to austenite. The influence of these reversion heat treatments on the product microstructure and its properties may be systematically discussed in terms of the heat treating temperature in relation to the phase diagram. From this perspective, four characteristic heat treatments are defined: (1) normal tempering, (2) inter-critical tempering, (3) intercritical annealing, and (4) austenite reversion. The reactions occurring during each of these treatments are described and the nature and properties of typical product microstructures discussed, with specific reference to new commercial or laboratory steels having useful and exceptional properties

  9. Balloons and Bottles: Activities on Air-Sea Heat Exchange.

    Science.gov (United States)

    Murphree, Tom

    1998-01-01

    Presents an activity designed to demonstrate how heating and cooling an air mass affects its temperature, volume, density, and pressure. Illustrates how thermal energy can cause atmospheric motion such as expansion, contraction, and winds. (Author/WRM)

  10. Forced convection heat transfer to air/water vapor mixtures

    International Nuclear Information System (INIS)

    Heat transfer coefficients were measured using both dry air and air/water vapor mixtures in the same forced convection cooling test rig (jet array impingement configurations) with mass ratios of water vapor to air up to 0.23. The primary objective was to verify by direct experiment that selected existing methods for evaluation of viscosity and thermal conductivity of air/water vapor mixtures could be used with confidence to predict heat transfer coefficients for such mixtures using as a basis heat transfer data for dry air only. The property evaluation methods deemed most appropriate require as a basis a measured property value at one mixture composition in addition to the property values for the pure components. 20 references

  11. An analysing of heat treatment process planning

    Directory of Open Access Journals (Sweden)

    B. Smoljan

    2007-01-01

    Full Text Available Purpose: Process planning of heat treatment has been investigated. The established approach of heat treatingprocess planning is suitable for effective integration of heat treatment in computer added manufacturing.Design/methodology/approach: Process plan of heat treating process has been established based on fundamentalprocess planning principals. The heat treatment was treated in the same as other manufacture processes.Findings: The general approach for process planning of heat treatment processes has been established. Heattreatment processes have to be designed into operations and sub-operations with the same principles that are alsovalid for other manufacturing processes.Research limitations/implications: The further research should be focused on development of methods for thebetter application of achieved results.Practical implications: This way of heat treatment process planning is more appropriate for integral trends ofmanufacturing, i.e., with the trend of introducing the modern systems in all parts of industrial manufacturing.Originality/value: The global approach of process planning of heat treatment processes was established andbetter unification with other manufacturing processes was achieved.

  12. Combustion Air Pre-heating from Ash Sensible Heat in Municipal Waste Incineration Systems

    OpenAIRE

    Zakariya Kaneesamkandi

    2014-01-01

    Heat recovery from bottom ash is more important in municipal waste combustion systems than in any other solid fuel combustion since almost 50% of it comprises of non-combustibles. In this study, an ash cooling system using air as the cooling medium has been modeled for pre-heating the combustion air. Air cooling has several advantages over water cooling methods. The study involves modeling using Gambit tool and is solved with the fluent solver. Municipal solid waste incineration systems have ...

  13. Continuous heating of an air-source heat pump during defrosting and improvement of energy efficiency

    International Nuclear Information System (INIS)

    Highlights: • The newly designed dual hot gas spray defrosting method was examined. • Uninterrupted heating of an air source heat pump during defrosting. • We compared newly designed dual hot gas and traditional reverse cycle defrost. • Total energy efficiency was increased by 8% compared to traditional method. - Abstract: During winter operation, an air-source heat pump extracts heat from the cold outside air and releases the heat into the living space. At certain outside air conditions, when it operates in heating mode, frost can form on the air-cooled heat exchanger, decreasing the heating performance. Conventionally, reverse-cycle defrosting (RCD) has been the common method of frost removal. But this method requires the interruption of heating during defrosting, as well as a period of time to reheat the cooled pipes of the indoor units after defrosting. In this study, a new technology called continuous heating was developed, which utilize only a hot gas bypass valve to remove the frost from the outdoor heat exchanger and thus enabling the supply of hot air to indoors without any interruption. For this, a new high temperature and low pressure gas bypass method was designed, which is differentiated from the common high pressure hot gas bypass methods by its use of low pressure. Various refrigerant mass flow distributions were examined, and the most effective defrosting mass flow was 50% in this case. Heating capacity was increased by 17% because of continuous heating, and the cumulated energy efficiency was increased by 8% compared to the traditional reverse cycle defrosting over 4 h including two defrost operations. Also, cumulated energy efficiency was increased by 27% compared to electronic heaters that supply the same heating capacity during defrosting. By this new technology, it has been proved that continuous heating and energy savings could be achieved without adopting expensive technologies

  14. Airborne Asbestos Exposures from Warm Air Heating Systems in Schools

    OpenAIRE

    Burdett, Garry J.; Dewberry, Kirsty; Staff, James

    2015-01-01

    The aim of this study was to investigate the concentrations of airborne asbestos that can be released into classrooms of schools that have amosite-containing asbestos insulation board (AIB) in the ceiling plenum or other spaces, particularly where there is forced recirculation of air as part of a warm air heating system. Air samples were collected in three or more classrooms at each of three schools, two of which were of CLASP (Consortium of Local Authorities Special Programme) system-built d...

  15. Heat treatment study 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Workman, G.L.

    1990-04-01

    The microstructural variations in nickel based superalloys that result from modifications in processing were examined. These superalloys include MAR-M246(HF) and PWA1480. Alternate heat treatments for equiaxed as-cast specimens were studied and a sample matrix of 42 variations in the heat treatments were processed, as well as different directional solidification parameters. Variation in temperature and times for both solution and aging were performed. Photomicrographs were made of the microstructure and volume fraction analysis of primary gamma-prime and aged gamma-prime precipitates were performed. The results of the heat treatment, cooling rate, and directional solidification experiments are discussed.

  16. WOOD MODIFICATION BY HEAT TREATMENT: A REVIEW

    Directory of Open Access Journals (Sweden)

    Bruno M. Esteves

    2009-02-01

    Full Text Available Wood heat treatment has increased significantly in the last few years and is still growing as an industrial process to improve some wood properties. The first studies on heat treatment investigated mainly equilibrium mois-ture, dimensional stability, durability and mechanical properties. Mass loss, wettability, wood color, and chemical transformations have been subsequently extensively studied, while recent works focus on quality control, modeling, and study the reasons for the improvements. This review explains the recent interest on the heat treatment of wood and synthesizes the major publications on this subject on wood properties, chemical changes, wood uses, and quality control.

  17. A fundamentally new approach to air-cooled heat exchangers.

    Energy Technology Data Exchange (ETDEWEB)

    Koplow, Jeffrey P.

    2010-01-01

    We describe breakthrough results obtained in a feasibility study of a fundamentally new architecture for air-cooled heat exchangers. A longstanding but largely unrealized opportunity in energy efficiency concerns the performance of air-cooled heat exchangers used in air conditioners, heat pumps, and refrigeration equipment. In the case of residential air conditioners, for example, the typical performance of the air cooled heat exchangers used for condensers and evaporators is at best marginal from the standpoint the of achieving maximum the possible coefficient of performance (COP). If by some means it were possible to reduce the thermal resistance of these heat exchangers to a negligible level, a typical energy savings of order 30% could be immediately realized. It has long been known that a several-fold increase in heat exchanger size, in conjunction with the use of much higher volumetric flow rates, provides a straight-forward path to this goal but is not practical from the standpoint of real world applications. The tension in the market place between the need for energy efficiency and logistical considerations such as equipment size, cost and operating noise has resulted in a compromise that is far from ideal. This is the reason that a typical residential air conditioner exhibits significant sensitivity to reductions in fan speed and/or fouling of the heat exchanger surface. The prevailing wisdom is that little can be done to improve this situation; the 'fan-plus-finned-heat-sink' heat exchanger architecture used throughout the energy sector represents an extremely mature technology for which there is little opportunity for further optimization. But the fact remains that conventional fan-plus-finned-heat-sink technology simply doesn't work that well. Their primary physical limitation to performance (i.e. low thermal resistance) is the boundary layer of motionless air that adheres to and envelops all surfaces of the heat exchanger. Within this

  18. The Impact of thermostatic expansion valve heating on the performance of air-source heat pumps in heating mode

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming [Oak Ridge National Laboratory, PO BOX 2008, MS6472, Oak Ridge, TN 37831-6472 (United States)

    2010-04-15

    This paper discusses the strategy of improving the efficiency of air-source heat pumps by adding a small amount of heat to the sensor of the thermostatic expansion valve (TXV). TXV heating retards the closing of the valve and boosts energy efficiency in heating mode. Test results demonstrate that appropriate TXV heating achieves an improvement in coefficient of performance (COP) and thermal comfort. The required heating power is no more than 40 W and the additional equipment cost is less than $20 at manufacturer cost (2006). Thus, the strategy of TXV heating is both technologically practical and low cost. (author)

  19. The Impact of thermostatic expansion valve heating on the performance of air-source heat pumps in heating mode

    Energy Technology Data Exchange (ETDEWEB)

    Gao Zhiming, E-mail: gaoz@ornl.go [Oak Ridge National Laboratory, PO BOX 2008, MS6472, Oak Ridge, TN 37831-6472 (United States)

    2010-04-15

    This paper discusses the strategy of improving the efficiency of air-source heat pumps by adding a small amount of heat to the sensor of the thermostatic expansion valve (TXV). TXV heating retards the closing of the valve and boosts energy efficiency in heating mode. Test results demonstrate that appropriate TXV heating achieves an improvement in coefficient of performance (COP) and thermal comfort. The required heating power is no more than 40 W and the additional equipment cost is less than $20 at manufacturer cost (2006). Thus, the strategy of TXV heating is both technologically practical and low cost.

  20. Combination of air-source heat pumps with liquid desiccant dehumidification of air

    International Nuclear Information System (INIS)

    Highlights: ► We propose a frost-free air-source heat pump system with integrated desiccant. ► The system can provide heating load continuously and humidify room. ► The coefficient of performance of the system is 2.6 at Ta = −7 °C and RH = 80%. ► The heating load of solution is 3–4 times larger than cooling load of solution. - Abstract: This paper proposes a frost-free air source heat pump system with integrated liquid desiccant dehumidification, in which frosting can be retarded by dehumidifying air before entering an outdoor heat exchanger. And the water removed from the air is used to humidify a room. Simulation is carried out at a dry-bulb temperature of −7 to 5.5 °C and a relative humidity of 80% depending on the frosting conditions. The results show that the coefficient of performance (COP) is in the range of 2.6–2.9, which is 30–40% higher than that of heat pump heating integrated with an electric heater humidifying system. And it is found that the optimum value of the concentration of lithium chloride aqueous solution is 37% for the frost-free operation mode. Experiments are conducted for liquid desiccant system under low air temperature and high relative humidity conditions. Experimental results show that the dew point of the dehumidified air is decreased by 8 °C and the humidity ratio of the humidified air is kept at 8.1 g kg−1, which ensures the frost-free operation of the heat pump evaporator and the comfortable level of room humidity simultaneously. The heating load of solution is 3–4.5 times larger than cooling load of solution, which agrees with the assumption given at the part of the simulation. Furthermore, the deviations between the calculated COPLHRU and the experimental results are within 33%.

  1. Evaporation heat flux from hot water to air flow

    International Nuclear Information System (INIS)

    In order to evaluate evaporation heat fluxes from coolant water in a spent fuel pit of a nuclear power plant to ventilation air during a shutdown of water purification and cooling systems, empirical correlations were derived. To derive correlations, the evaporation heat transfer databases at Shinshu University, which were obtained using test sections A and B with heat transfer lengths of 940 mm and 300 mm, were used. The temperatures of the hot water and air were 35-65°C and about 20°C, respectively, and air velocity was up to 2.08 m/s. In this study, a correlation including length scale was derived using the database under the outlet relative humidity less than 100% (Xout out = 1.0) in the test section A were corrected using the heat flux data with Xout < 1.0 in the test section B in order to obtain evaporation heat fluxes under 100% relative humidity (X = 1.0) conditions, which might be applied to a spent fuel pit with the length scale of about 10 m. Then, another correlation without the length scale was introduced from the heat fluxes corrected for conditions of X = 1.0. The heat fluxes for the length scale of 10 m calculated using the two correlations agreed each other. (author)

  2. Effects of heat treatment on properties of boron nitride fiber

    Institute of Scientific and Technical Information of China (English)

    LI Duan; ZHANG ChangRui; LI Bin; CAO Feng; WANG SiQing

    2012-01-01

    The boron nitride fibers were heated at the range of 600-1400°C in flowing nitrogen and air,respectively,and the effects of heat treatment on the structure,composition and morphology of BN fibers were studied.The results showed that BN fibers exhibited smooth surfaces,and that t-BN was the main phase with a little B2O3 included.After heat treatment at 1400°C in nitrogen atmosphere,the fibers displayed rough surfaces with little change in mass.Better crystallinity was obtained with the increasing temperature.During heat treatment in air,the fibers were oxidized severely as the temperature went up,especially at 1400°C.The volatilization of B2O3,HBO2 and H3BO3 led to the pores on the surfaces of the fibers,while the boron oxide glaze and nitrogen gas produced during the oxidation process protected the fibers from further oxidation.

  3. Dynamic modeling of an air source heat pump water heater

    OpenAIRE

    Fardoun, Farouk; Ibrahim, Oussama; Zoughaib, Assaad

    2011-01-01

    International audience This paper presents a dynamic simulation model to predict the performance of an air source heat pump water heater (ASHPWH). The mathematical model consists of submodels of the basic system components i.e. evaporator, condenser, compressor, and expansion valve. These submodels were built based on fundamental principles of heat transfer, thermodynamics, fluid mechanics, empirical relationships and manufacturer's data as necessary. The model simulation was carried out u...

  4. Combustion Air Pre-heating from Ash Sensible Heat in Municipal Waste Incineration Systems

    Directory of Open Access Journals (Sweden)

    Zakariya Kaneesamkandi

    2014-01-01

    Full Text Available Heat recovery from bottom ash is more important in municipal waste combustion systems than in any other solid fuel combustion since almost 50% of it comprises of non-combustibles. In this study, an ash cooling system using air as the cooling medium has been modeled for pre-heating the combustion air. Air cooling has several advantages over water cooling methods. The study involves modeling using Gambit tool and is solved with the fluent solver. Municipal solid waste incineration systems have the advantage of being located near the waste collection area apart from the high volume reduction ratio. Improvements in the emission control systems and combustion technology can make incineration a highly feasible disposal method. Low furnace temperature due to heat losses through fuel moisture loss and ash sensible heat loss has been a disadvantage with these systems. In this study, a small percentage of the combustion air is pre-heated in a non-contact type heat exchanger and its effect on the available energy of combustion gases at the evaporator outlet is studied. The study is performed for two different waste samples. Results indicate significant increase in available energy at the evaporator outlet and better relative performance for the lower grade fuel. A comparison is made with similar methods reported in the literature along with a brief discussion on the methodologies adopted. The results confirm the importance of installing ash sensible heat recovery mechanism for waste incineration systems as well as the feasibility of the air based method.

  5. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    Directory of Open Access Journals (Sweden)

    Sabanskis A.

    2016-04-01

    Full Text Available Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

  6. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    Science.gov (United States)

    Sabanskis, A.; Virbulis, J.

    2016-04-01

    Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

  7. Heat-treatment and heat-to-heat variations in the fracture toughness of Alloy 718

    International Nuclear Information System (INIS)

    The effect of heat-treatment and heat-to-heat variations on the JIc fracture toughness response of Alloy 718 was examined at room and elevated temperatures using the multiple-specimen R-curve technique. Six heats of alloy 718 were tested in the conventional and modified heat-treated conditions. The fracture toughness response for the modified superalloy was found to be superior to that exhibited by the conventional material. Heat-to-heat variations in the JIc response of Alloy 718 were observed in both heat-treated conditions; the modified treatment exhibited much larger variability. The JIc and corresponding KIc fracture toughness values were analyzed statistically to establish minimum expected toughness, values for use in design and safety analyses. 26 refs., 10 figs., 9 tabs

  8. Performance of cylindrical plastic solar collectors for air heating

    International Nuclear Information System (INIS)

    Highlights: • The study including the combined convective and radiative heat transfer analysis. • The solar collector is manufactured from LDPE films acting as a black absorber. • Comparisons between the experimental data and the theoretical methods have been made. • The thermal efficiency increases with decreasing the major axes of elliptic shape. • The Nusselt number between the absorber and the heated air is determined. - Abstract: A theoretical and experimental study including the combined convective and radiative heat transfer analysis of a flexible cylindrical type solar air-heater for agriculture crops dehydration as well as heating processes is presented. The solar collector is manufactured from LDPE films acting as a black absorber with a back insulation and double transparent covers sealed together along its edges. The collector is to be blown with a flow of pressurized air. The experiments are carried out with solar collectors of circular shapes having 0.5 m diameter and solar collectors of elliptic shapes having 0.55 m and 0.65 m major axis. Energy balance of the cover, absorber and air yield three simultaneous quadratic algebraic equations in the three unknowns namely, cover, absorber and outlet air temperatures. A computer program is written for calculating the outlet temperature using the Newton–Raphson method and the collector thermal efficiency in terms of its diameter, length, mass flow rate, inlet temperature and solar insolation. Moreover the Nusselt number between the absorber and the heated air is determined experimentally in relation with the Reynolds number. Comparisons between the experimental data and the theoretical methods for the collector efficiency demonstrate a good agreement. In addition of this, the present experimental results of Nusselt number are correlated and compared with a correlation of another authors

  9. Failures of tool steels after heat treatments

    International Nuclear Information System (INIS)

    The main objective of the work was to determine the most common defects occuring in tool steels of the AISI D-2, S-1, 0-1 and W-2 series during thermal treatment. Defects were evaluated by metallographic analyses, a method used to determine and recognize micro structural defects and their origin in order to be able to eliminate and correct some of the stages that are caused by heat treatment. Results show a large number of defects due to irregularities during thermal heating such as excess or lack of temperature, heating time, and atmosphere, rectifying and handling in service and, to a lesser extent, poor design. In conclusion, with the results obtained for each of the thermal treatments it is necessary to define, particularly the values each of these variables should have since they affect the material properties. (Author)

  10. Air-side Particulate Fouling of Microchannel Heat Exchangers: Experimental Comparison of Air-Side Pressure Drop and Heat Transfer with Plate-Fin Heat Exchanger

    OpenAIRE

    Bell, Ian; Groll, Eckhard

    2011-01-01

    In this study, the air-side pressure drop and heat transfer performance of plate-fin and microchannel coils were tested under clean and fouled conditions. The heat exchangers were tested with two different types of dust, ASHRAE Standard Dust and Arizona Road Test Dust. The ASHRAE Standard Dust was found to have a very significant impact on the pressure drop of the microchannel heat exchanger, increasing the air-side pressure drop of the microchannel heat exchanger over 200% for a dust injec...

  11. Air-source heat pump carbon footprints: HFC impacts and comparison to other heat sources

    International Nuclear Information System (INIS)

    European governments see that heat pumps could reduce carbon emissions in space- and hot-water heating. EU's Renewable Energy Directive designates heat pumps as renewable - eligible for various subsidies - if their carbon footprints are below an implied, average threshold. This threshold omits carbon generated by manufacture and emission of a heat-pump's fluorocarbon refrigerant. It also omits the footprint of the heat pump's hardware. To see if these omissions are significant, this study calculated carbon footprints of representative, residential heat pumps in the UK. Three findings emerged. First, in relation to power generation, which accounts for most of a heat-pump's greenhouse-gas emissions, fluorocarbons add another 20% to the footprint. Second, at UK efficiencies a heat-pump footprint (in kg CO2e emitted per kWh delivered) is comparable or higher than footprints of gaseous fuels used in heating. It is lower than the footprint of heating oil and far lower than the footprints of solid fuels. Third, production and disposal of a heat pump's hardware is relatively insignificant, accounting for only 2-3% of the overall heat-pump footprint. Sensitivities to the results were assessed: key factors are footprint of electricity generation, F-gas composition and leak rates and type of wall construction. - Research highlights: → Refrigerant emissions add 20% to a UK air-source heat pump's carbon footprint. → This contribution is so far ignored by regulations. → UK heat pump footprints are comparable to those of gaseous fuels.

  12. Cast functional accessories for heat treatment furnaces

    Directory of Open Access Journals (Sweden)

    A. Drotlew

    2010-10-01

    Full Text Available The study gives examples of the cast functional accessories operating in furnaces for the heat treatment of metals and alloys. The describeddesign solutions of castings and their respective assemblies are used for charge preparation and handling. They were put in systematicorder depending on furnace design and the technological purpose of heat treatment. Basic grades of austenitic cast steel, used for castings of this type, were enumerated, and examples of general guidelines formulated for their use were stated. The functional accessories described in this study were designed and made by the Foundry Research Laboratory of West Pomeranian University of Technology.

  13. Advanced Print Reading. Heating, Ventilation and Air Conditioning.

    Science.gov (United States)

    Oregon State Dept. of Education, Salem.

    This is a workbook for students learning advanced blueprint reading for heating, ventilation, and air conditioning applications. The workbook contains eight units covering the following material: architectural working drawings; architectural symbols and dimensions; basic architectural electrical symbols; wiring symbols; basic piping symbols;…

  14. EnergyPlus Air Source Integrated Heat Pump Model

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division; Adams, Mark B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division; New, Joshua Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division

    2016-03-30

    This report summarizes the development of the EnergyPlus air-source integrated heat pump model. It introduces its physics, sub-models, working modes, and control logic. In addition, inputs and outputs of the new model are described, and input data file (IDF) examples are given.

  15. State Skill Standards: Heating, Ventilation, Air Conditioning, and Refrigeration

    Science.gov (United States)

    Ball, Larry; Soukup, Dennis

    2006-01-01

    The Department of Education has undertaken an ambitious effort to develop statewide career and technical education skill standards. The standards in this document are for Heating, Ventilation, Air Conditioning and Refrigeration (HVAC&R) programs and are designed to clearly state what the student should know and be able to do upon completion of an…

  16. Heating, Air-Conditioning, and Refrigeration Technician. National Skill Standards.

    Science.gov (United States)

    Vocational Technical Education Consortium of States, Decatur, GA.

    This guide contains information on the knowledge and skills identified by industry as essential to the job performance of heating, air-conditioning, and refrigeration technicians. It is intended to assist training providers in public and private institutions, as well as in industry, to develop and implement training that will provide workers with…

  17. Air Conditioning, Heating, and Refrigeration: Scope and Sequence.

    Science.gov (United States)

    Nashville - Davidson County Metropolitan Public Schools, TN.

    This scope and sequence guide, developed for an air conditioning, heating, and refrigeration vocational education program, represents an initial step in the development of a systemwide articulated curriculum sequence for all vocational programs within the Metropolitan Nashville Public School System. It was developed as a result of needs expressed…

  18. Air Conditioning, Heating, and Refrigeration. Competency-Based Curriculum Manual.

    Science.gov (United States)

    Gourley, Frank A., Jr.

    This manual was developed to serve as an aid to administrators and instructors involved with postsecondary air conditioning, heating, and refrigeration programs. The first of six chapters contains general information on program implementation, the curriculum design, facilities and equipment requirements, and textbooks and references. Chapter 2…

  19. Urban heat : natural and anthropogenic factors influencing urban air temperatures

    NARCIS (Netherlands)

    Theeuwes, N.E.

    2015-01-01

    The urban heat island effect is a phenomenon observed worldwide, i.e. evening and nocturnal temperatures in cities are usually several degrees higher than in the surrounding countryside. The main goal of this thesis is to understand the processes that drive the urban air temperature and the urban he

  20. 49 CFR 179.220-11 - Postweld heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.220-11 Section 179... Postweld heat treatment. (a) Postweld heat treatment of the inner container is not a specification requirement. (b) Postweld heat treatment of the cylindrical portions of the outer shell to which the...

  1. Modelling heat and mass transfer in a membrane-based air-to-air enthalpy exchanger

    Science.gov (United States)

    Dugaria, S.; Moro, L.; Del, D., Col

    2015-11-01

    The diffusion of total energy recovery systems could lead to a significant reduction in the energy demand for building air-conditioning. With these devices, sensible heat and humidity can be recovered in winter from the exhaust airstream, while, in summer, the incoming air stream can be cooled and dehumidified by transferring the excess heat and moisture to the exhaust air stream. Membrane based enthalpy exchangers are composed by different channels separated by semi-permeable membranes. The membrane allows moisture transfer under vapour pressure difference, or water concentration difference, between the two sides and, at the same time, it is ideally impermeable to air and other contaminants present in exhaust air. Heat transfer between the airstreams occurs through the membrane due to the temperature gradient. The aim of this work is to develop a detailed model of the coupled heat and mass transfer mechanisms through the membrane between the two airstreams. After a review of the most relevant models published in the scientific literature, the governing equations are presented and some simplifying assumptions are analysed and discussed. As a result, a steady-state, two-dimensional finite difference numerical model is setup. The developed model is able to predict temperature and humidity evolution inside the channels. Sensible and latent heat transfer rate, as well as moisture transfer rate, are determined. A sensitive analysis is conducted in order to determine the more influential parameters on the thermal and vapour transfer.

  2. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    OpenAIRE

    Sabanskis A.; Virbulis J.

    2016-01-01

    Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Result...

  3. Heat treatment of uranium-bearing shale

    International Nuclear Information System (INIS)

    In view of the difficulties encountered in rendering soluble the uranium content of shales worked in the Vosges region, and in their filtration after attack, the effects of heat treatment at high temperatures (300 to 600 deg. C) on these two factors is discussed. The first part deals with tests in static beds, the second in fluid beds. In both cases calorie recovery is discussed. The treatment improves filtration but not solubility. (author)

  4. Experimental Study on Match for Indoor and Outdoor Heat Exchanger of Residential Air-conditioner

    OpenAIRE

    Tu, Xiaoping; Liang, Xiangfei; Zhuang, Rong

    2014-01-01

    In this study, the effects of indoor unit heat transfer area and air flow rate and outdoor unit air flow rate on the system performance of residential air-conditioner were experimentally investigated under rated cooling and heating conditions. The experimental results showed that the system cooling capacity, EER, heating capacity and COP all had evident variation with indoor unit heat transfer area and air flow rate and out unit air flow rate, which predicated that there was a proper match ra...

  5. Estimating ocean-air heat fluxes during cold air outbreaks by satellite

    Science.gov (United States)

    Chou, S. H.; Atlas, D.

    1981-01-01

    Nomograms of mean column heating due to surface sensible and latent heat fluxes were developed. Mean sensible heating of the cloud free region is related to the cloud free path (CFP, the distance from the shore to the first cloud formation) and the difference between land air and sea surface temperatures, theta sub 1 and theta sub 0, respectively. Mean latent heating is related to the CFP and the difference between land air and sea surface humidities q sub 1 and q sub 0 respectively. Results are also applicable to any path within the cloud free region. Corresponding heat fluxes may be obtained by multiplying the mean heating by the mean wind speed in the boundary layer. The sensible heating estimated by the present method is found to be in good agreement with that computed from the bulk transfer formula. The sensitivity of the solutions to the variations in the initial coastal soundings and large scale subsidence is also investigated. The results are not sensitive to divergence but are affected by the initial lapse rate of potential temperature; the greater the stability, the smaller the heating, other things being equal. Unless one knows the lapse rate at the shore, this requires another independent measurement. For this purpose the downwind slope of the square of the boundary layer height is used, the mean value of which is also directly proportional to the mean sensible heating. The height of the boundary layer should be measurable by future spaceborn lidar systems.

  6. Assembly for melting and heat treatment

    International Nuclear Information System (INIS)

    Laboratory scale production of alloys having a precise alloying materials content and the exact heat treatment of metallurgical specimens are discussed. The design and assembly of two relevant instruments are described. These instruments include a laboratory vacuum induction furnace and a specially designed glass lathe, that enables even an unskilled operator to encapsulate and seal metallurgical specimens in glass capsules. (author)

  7. Measuring important parameters for air-sea heat exchange

    Science.gov (United States)

    Garbe, Christoph; Schimpf, Uwe; Jaehne, Bernd

    2002-03-01

    The heat transfer between the ocean and the atmosphere is one of the most important parameters governing the global climate. Important parameters include the heat transfer velocity and the net heat flux as well as parameters of the underlying transport model. However, the net heat flux is hard to measure since processes take place in the thermal boundary layer, that is the topmost layer of the ocean less than 1 mm thick. Current techniques rely on three independent measurements of the constituent fluxes, the sensible heat flux, latent heat flux and radiative flux. They depend on indirect measurements of meteorological parameters and rely on a combination of data from different sensors using a number of heuristic assumptions. High relative errors and the need for long temporal averaging reduce the practicability of these techniques. In this paper a novel technique is presented that circumvents these drawbacks by directly measuring the net heat flux across the air-water interface with a single low-NETD infrared camera. A newly developed digital image processing technique allows to simultaneously estimating the surface velocity field and parameters of the temporal temperature change. In particular, this technique allows estimating the total derivative of the temperature with respect to time from a sequence of infrared images, together with error bounds on the estimates. This derivative can be used to compute the heat flux density and the heat transfer velocity, as well as the probability density function of the underlying surface renewal model. It is also possible to estimate the bulk-skin temperature difference given rise to by the net heat flux. Our technique has been successfully used in both laboratory measurements in the Heidelberg Aeolotron, as well as in field measurements in the equatorial pacific during the NOAA GasExII experiment this spring. The data show that heat flux measurements to an accuracy of better than 5% on a time scale of seconds are feasible.

  8. Energy-optimised heat treatment; Energieoptimierte Waermebehandlung

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Dominik [LOI Thermprocess GmbH, Essen (Germany)

    2012-06-15

    Energy efficiency starts with plant engineering: the burner technology represents an essential factor. Even an optimal efficiency in firing technology will, however, only lead to energy efficiency if process and production are both thoroughly adjusted to the plant and plant capacity. This conversely means that a plant should be provided according to process- and production-specific requirements. Possibilities of process optimization in the steel- and aluminium heat treatment are illustrated in this article, focusing on plant utilisation, heating-up curve and dynamic processes of structural changes. (orig.)

  9. Development of solar driven absorption air conditioners and heat pumps

    Science.gov (United States)

    Dao, K.; Wahlig, M.; Wali, E.; Rasson, J.; Molishever, E.

    1980-03-01

    The development of absorption refrigeration systems for solar active heating and cooling applications is discussed. The approaches investigated are those using air-cooled condenser-absorber and those leading to coefficient of performances (COP) that increase continuously with heat source temperature. This is primarily an experimental project, with the emphasis on designing, fabricating and testing absorption chillers in operating regimes that are particularly suited for solar energy applications. Its demonstrated that the conventional single-effect ammonia-water absorption cycle can be used (with minor modifications) for solar cooling.

  10. The necessity for and possibilities of heat treatment

    International Nuclear Information System (INIS)

    Present day pressure vessel manufacture is inconceivable without welding techniques. Welding processes lead to the necessity for heat treatment, so that the structure can be improved by tempering, annealing or reannealing or normalisation. One can only do without heat treatment after welding, if the boundary conditions in the regulations are observed. Heating furnaces, gas burners, inductive heating and resistance heating are suitable for heat treatment. (DG)

  11. Thermomechanical treatment of heat-resisting alloys

    International Nuclear Information System (INIS)

    Different types of thermomechanical treatment (TMT) are considered in the review. Three schemes which are used for heat resistant ageing alloys are singled out and described in detail: high-temperature thermomechanical treatment (HTMT), mechanico-thermal treatment (MTT) and low-temperature thermomechanical treatment (LTMT). Special attention is paid to perspective LTMT including warm deformation. It is shown that the application of the TMT to concrete alloys permits to increase the strength characteristics in a certain temperature range of the product exploitation without considerable plasticity loss. TMT with the use.of warm deformation in two-phase region looks like the most perspective treatment increasing strength properties, resistance against fatigue destruction and decreasing the sensitivity to the cut

  12. Investigation of heat exchanger inclination in forced-draught air-cooled heat exchangers

    OpenAIRE

    Kennedy, I.J.; Spence, S.W.T.; Spratt, G.R.; Early, J. M.

    2013-01-01

    The purpose of this study is to determine the influence of inclining the heat exchanger relative to the fan in a forced draught air-cooled heat exchanger. Since inclination increases plenum depth, the effect of inclination is also compared with increasing plenum depth without inclination. The experimental study shows that inclination improves thermal performance by only 0.5%, when compared with a baseline non-inclined case with a shallow plenum. Similarly, increasing plenum depth without incl...

  13. Experimental Study of the Performance of Air Source Heat Pump Systems Assisted by Low-Temperature Solar-Heated Water

    OpenAIRE

    Jinshun Wu; Chao Chen; Song Pan; Jun Wei; Tianquan Pan; Yixuan Wei; Yunmo Wang; Xinru Wang; Jiale Su

    2013-01-01

    Due to the low temperatures, the heating efficiency of air source heat pump systems during the winter is very low. To address this problem, a low-temperature solar hot water system was added to a basic air source heat pump system. Several parameters were tested and analyzed. The heat collection efficiency of the solar collector was analyzed under low-temperature conditions. The factors that affect the performance of the heat pumps, such as the fluid temperature, pressure, and energy savings, ...

  14. Induction heat treatment of laser welds

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove; Sørensen, Joakim Ilsing

    2003-01-01

    the laser beam as close as possible. After welding, the samples were quality assessed according to ISO 13.919-1 and tested for hardness. The metallurgical phases are analysed and briefly described. A comparison between purely laser welded samples and induction heat-treated laser welded samples is made....... The temperature measurements show that, with the chosen mechanical set-up of laser and induction coil, it is difficult to obtain a quick increase to around 300º C, the temperatures required for efficient heat-treatment with the induction coil alone. Despite this, a reduction in the hardness values of...... both GA260 and CMn were recorded when laser welded samples were induction heat-treated. The reduction was 6 to 8 % for GA260 and 41 to 45 % for CMn, respectively. GA260 displays a ferrite structure in basic and welded form, whereas CMn, with ten times more carbon, shows a ferrite and bainite structure...

  15. Induction heat treatment of laser welds

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove; Sørensen, Joakim Ilsing

    2003-01-01

    In this paper, a new approach based on induction heat-treatment of flat laser welded sheets is presented. With this new concept, the ductility of high strength steels GA260 with a thickness of 1.8 mm and CMn with a thickness of 2.13 mm is believed to be improved by prolonging the cooling time from...... induction coil. A number of systematic laboratory tests were then performed in order to study the effects of the coil on bead-on-plate laser welded samples. In these tests, important parameters such as coil current and distance between coil and sample were varied. Temperature measurements were made at...... distances of 0, 2 and 4 mm away from the virtual weld line for the induction heating process and at distances of 2 and 4 mm for the laser welding with induction heating process. For practical reasons during performance of these laboratory experiments, the induction coil was placed below the sheets, trailing...

  16. Development of an Air-Source Heat Pump Integrated with a Water Heating / Dehumidification Module

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C Keith [ORNL; Uselton, Robert B. [Lennox Industries, Inc; Shen, Bo [ORNL; Baxter, Van D [ORNL; Shrestha, Som S [ORNL

    2014-01-01

    A residential-sized dual air-source integrated heat pump (AS-IHP) concept is under development in partnership between ORNL and a manufacturer. The concept design consists of a two-stage air-source heat pump (ASHP) coupled on the air distribution side with a separate novel water heating/dehumidification (WH/DH) module. The motivation for this unusual equipment combination is the forecast trend for home sensible loads to be reduced more than latent loads. Integration of water heating with a space dehumidification cycle addresses humidity control while performing double-duty. This approach can be applied to retrofit/upgrade applications as well as new construction. A WH/DH module capable of ~1.47 L/h water removal and ~2 kW water heating capacity was assembled by the manufacturer. A heat pump system model was used to guide the controls design; lab testing was conducted and used to calibrate the models. Performance maps were generated and used in a TRNSYS sub-hourly simulation to predict annual performance in a well-insulated house. Annual HVAC/WH energy savings of ~35% are predicted in cold and hot-humid U.S. climates compared to a minimum efficiency baseline.

  17. In situ heat treatment process utilizing a closed loop heating system

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Nguyen, Scott Vinh (Houston, TX)

    2010-12-07

    Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some embodiments, the piping may be positioned in at least two of the wellbores.

  18. Fabrication techniques to eliminate postweld heat treatment

    International Nuclear Information System (INIS)

    Postweld heat treatments to reduce residual stresses (stress relief operations) have been a common practice in the pressure vessel industry for a large number of years. A suitable heat treatment operation can, in particular for low alloy steels, have additional beneficial effects, i.e. a reduction in peak hardness values in the heat-affected zone, an improvement in weld metal properties, and a lowering of the adverse effects of the welding process on the mechanical properties of the parent material adjacent to the weld metal. However, continuing studies in the field of brittle fracture, improved parent materials, and more sophisticated nondestructive testing techniques have led to the elimination of such a practice in ever-increasing thickness ranges and types of material. For instance, the recently issued BS 5500 compared with BS 1113 (1969) lifts the thickness limit requiring stress relief in certain circumstances from 19 to 35mm for C steels. With respect to materials the CEGB has stated that as a result of successful operational experience it will no longer be necessary to postweld heat treat butt welds in 2 1/4 Cr-1Mo tubes of certain dimensions. Despite this trend, over a period of years a number of instances have arisen where, because of some factor, postweld heat treatment, although perhaps desirable, is not possible. This Paper describes several such examples. It must be noted that the examples quoted consist of relatively important and major items. It has been necessary within the confines of this Paper to condense the reports. It is hoped that no significant factors have been omitted. (author)

  19. Airshuffler implementation at freezer air outlets for heat transfer enhancement

    Science.gov (United States)

    Ćerezci, Gökhan; Darka, Murat; Şenman, Ozan

    2016-06-01

    A study which is composed of computational simulation and experimental validation has been conducted for implementation of small, vane type geometries at freezer air outlets, similar to microvortex generators used in aircraft wings, in order to improve the heat transfer efficiency inside the freezer compartment by decreasing airside thermal resistance and improving the air distribution. Both simulation and experimental validation were performed in a loaded condition which was prepared according to `Household refrigerating appliances - characteristics and test methods - IEC 62552 [1]. Solutions for the incompressible K-epsilon (k-ɛ) turbulence model obtained for Bosch KDN 49 refrigerator freezer both with and without airshufflers at air outlets, which are similar to vane type microvortex generators with different geometric dimensions. The airshuffler dimensions were chosen with design of experiment (DOE) principles for finding the optimum geometry. The best combinations were tested according to cooling rate inside freezer compartment. Results were evaluated for feasibility of implementing of vortex generating surfaces (airshufflers) for cooling appliances.

  20. The heat treatment of Fermanal cast steel

    OpenAIRE

    F. Binczyk; A. Smoliński; J. Szymszal

    2007-01-01

    The study discloses the results of microstructural examinations, testing of magnetic properties and hardness measurements as cast and after heat treatment conducted on the Fermanal cast steel. A characteristic feature of this cast steel is its density lower by about 10% than the density of carbon cast steel [4]. It has been proved that the factor deciding about the composition of microstructure (fraction of ferrite and austenite) is the content of aluminium. The matrix totally austenitic is p...

  1. Heat Treatment of the Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    Joo; Beom; Eom; Seongwoo; Yoo; Jinchae; Kim; Hokyung; Kim; Un-Chul; Paek; Byeong; Ha; Lee

    2003-01-01

    We report heat treatment of the photonic crystal fiber. As the temperature was increased, the transmission of the photonic crystal fiber was increased, unlike conventional single mode fiber. The transmission increase at short wavelength region was larger than long wavelength region for the various temperatures. After crystallization of the silica glass, the spectra of the photonic crystal fiber were just decreased at all wavelength regions, but, in case of the single mode fiber, the absorption in visibl...

  2. District Heating Mode Analysis Based on an Air-cooled Combined Heat and Power Station

    Directory of Open Access Journals (Sweden)

    Pei Feng Li

    2014-03-01

    Full Text Available As an important research subject, district heating with combined heat and power (CHP has significant potential for energy conservation. This paper utilised a 200 MW air-cooled unit as an actual case and presented a design scheme and energy consumption analysis of three typical CHP modes, including the low vacuum mode (LVM, the extraction condensing mode (ECM, and the absorbing heat pump mode (AHPM. The advantages and disadvantages of each mode (including their practical problems were analysed, and suggestions for the best mode were proposed. The energy consumption of the three heating modes changed with the heating load. When the heating load was increased, the net power of the entire system decreased to different degrees. In this paper, the energy conservation effect of the LVM was the most ideal, followed by the ECM and the AHPM. Besides, the LVM and AHPM were able to supply larger heat loads than the ECM, which was limited by the minimum cooling flow of the low pressure cylinder. Furthermore, in order to get a more general conclusion, a similar case with an air-cooled 300 MW unit is studied, showing that the fuel consumption levels of ECM and AHPM have changed.

  3. Operation Performance of Air Source Heat Pump System for Space Heating in Tianjin

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; CHEN Yan; QU Hang; LI Xinguo

    2007-01-01

    An air source heat pump system (ASHPS) used in an office building is set up and studied experimentally. Its operating performance in winter is evaluated based on test data and a comparative discussion is given on the effect of climate conditions and heating load ratio on the operation behavior.Then heating capacity variation caused by evaporator frosting is analyzed as well. Finally, the defrosting parameters and the technical feasibility are studied for a constant heating demand. The experimental results indicate that both the outlet water temperature drop and the system COP should be taken into account when setting defrosting parameters, and ASHPS is a viable technology for space heating and hotwater production in winter in Tianjin, which can maintain the room temperature above 19 ℃ when the outdoor temperature is -2 ℃.

  4. Modeling of Air Temperature for Heat Exchange due to Vertical Turbulence and Horizontal Air Flow

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; MENG Qing-lin

    2009-01-01

    In order to calculate the air temperature of the near surface layer in urban environment,the Sur-face layer air was divided into several layers in the vertical direction,and some energy bakmce equations were de-veloped for each air layer,in which the heat exchange due to vertical turbulence and horizontal air flow was tak-en into account.Then,the vertical temperature distribution of the surface layer air was obtained through the coupled calculation using the energy balance equations of underlying surfaces and building walls.Moreover,the measured air temperatures in a small area (with a horizontal scale of less than 500 m) and a large area (with ahorizontal scale of more than 1000 m) in Guangzhou in summer were used to validate the proposed model.The calculated results agree well with the measured ones,with a maximum relative error of 4.18%.It is thus con-cluded that the proposed model is a high-accuracy method to theoretically analyze the urban heat island and the thermal environment.

  5. Dynamic model of counter flow air to air heat exchanger for comfort ventilation with condensation and frost formation

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Rose, Jørgen; Kragh, Jesper

    2009-01-01

    In cold climates heat recovery in the ventilation system is essential to reduce heating energy demand. Condensation and freezing occur often in efficient heat exchangers used in cold climates. To develop efficient heat exchangers and defrosting strategies for cold climates, heat and mass transfer...... on a prototype heat exchanger for cold climates....... must be calculated under conditions with condensation and freezing. This article presents a dynamic model of a counter flow air to air heat exchanger taking into account condensation and freezing and melting of ice. The model is implemented in Simulink and results are compared to measurements...

  6. Design of Solar Heat Sheet for Air Heaters

    Science.gov (United States)

    Priya, S. Shanmuga; Premalatha, M.; Thirunavukkarasu, I.

    2011-12-01

    The technique of harnessing solar energy for drying offers significant potential to dry agricultural products such as food grains, fruits, vegetables and medicinal plants, thereby eliminating many of the problems experienced with open-sun drying and industrial drying, besides saving huge quantities of fossil fuels. A great deal of experimental work over the last few decades has already demonstrated that agricultural products can be satisfactorily dehydrated using solar energy. Various designs of small scale solar dryers have been developed in the recent past, mainly for drying agricultural products. Major problems experienced with solar dryers are their non-reliability as their operation largely depends on local weather conditions. While back-up heaters and hybrid dryers partly solved this issue, difficulties in controlling the drying air temperature and flow rate remains a problem, and affects the quality of the dried product. This study is aimed at eliminating the fluctuations in the quality of hot air supplied by simple solar air heaters used for drying fruits, vegetables and other applications. It is an attempt to analyse the applicability of the combination of an glazed transpired solar collector (tank), thermal storage and a intake fan(suction fan) to achieve a steady supply of air at a different atmospheric temperature and flow rate for drying fruits and vegetables. Development of an efficient, low-cost and reliable air heating system for drying applications is done.

  7. Integration of heat treatment of wood with cogeneration production and district heating; Vaermebehandling av trae integrerad med kraftvaermeproduktion och fjaerrvaerme

    Energy Technology Data Exchange (ETDEWEB)

    Delin, Lennart; Essen, Henrik (AaF, Stockholm (Sweden))

    2011-05-15

    Heat treatment of wood changes the properties of wood so that the moisture uptake is reduced and the wood movements are reduced at variations in the ambient air humidity. The wood gets an increased resistance to rot and can therefore replace impregnated wood in certain applications. Heat treated wood is however not suitable for direct contact with soil. The strength is also reduced by heat treatment, so it is not recommended for supporting constructions. No additives whatsoever are used in the treatment, so the heat treated wood is very advantageous from an environmental point of view. The wood is dried completely at the heat treatment and heated to about 200 deg C. The question has hence been put, if it is advantageous to collocate a heat treatment plant with district heating or a power cogeneration plant. The aim of the study is to assess the value of such a collocation. Existing heat treatment plants are both few and small and the calculations have hence been made for how a large plant could be designed. A market study is included to assess the market for this type of plants. This shows that the present market for heat treated wood is very small. A full scale treatment plant of the type discussed in this study could probably not be built, since even single plants of this size would require a too large part of the market. The potential to replace impregnated wood is on the other hand very large. The cost for large scale heat treatment should be significantly lower than for impregnated wood and the cost for handling hazardous waste (which impregnated wood is classified as) is also removed. There should therefore be a potential for a future much larger volume of heat treated wood. The study shows that the energetic profit of collocation of a heat treatment plant for wood with district heating or power cogeneration plants is of lower importance. Maximally about 0.5 MSEK/year can be saved for a 25 000 m3/year plant. The initial drying of all sawn lumber has much more

  8. Numerical Investigation of Air-Side Heat Transfer and Pressure Drop in Circular Finned-Tube Heat Exchangers

    OpenAIRE

    Mon, Mi Sandar

    2009-01-01

    A three-dimensional numerical study is performed to investigate the heat transfer and pressure drop performance on the air-side of circular finned tube bundles in cross flow. New heat transfer and pressure drop correlations for the air-cooled heat exchangers have been developed with the Reynolds number ranging from 5000 to 70000. The heat transfer and pressure drop results agree well with several existing experimental correlations. In addition, the influence of the geometric parameters on the...

  9. 7 CFR 305.25 - Dry heat treatment schedules.

    Science.gov (United States)

    2010-01-01

    ... treating equipment in order to determine that all niger seed being treated reaches the target temperature... 7 Agriculture 5 2010-01-01 2010-01-01 false Dry heat treatment schedules. 305.25 Section 305.25... SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Heat Treatments § 305.25 Dry heat...

  10. An experimental investigation on air-side performances of finned tube heat exchangers for indirect air-cooling tower

    Directory of Open Access Journals (Sweden)

    Du Xueping

    2014-01-01

    Full Text Available A tremendous quantity of water can be saved if the air cooling system is used, comparing with the ordinary water-cooling technology. In this study, two kinds of finned tube heat exchangers in an indirect air-cooling tower are experimentally studied, which are a plain finned oval-tube heat exchanger and a wavy-finned flat-tube heat exchanger in a cross flow of air. Four different air inlet angles (90°, 60 °, 45°, and 30° are tested separately to obtain the heat transfer and resistance performance. Then the air-side experimental correlations of the Nusselt number and friction factor are acquired. The comprehensive heat transfer performances for two finned tube heat exchangers under four air inlet angles are compared. For the plain finned oval-tube heat exchanger, the vertical angle (90° has the worst performance while 45° and 30° has the best performance at small ReDc and at large ReDc, respectively. For the wavy-finned flat-tube heat exchanger, the worst performance occurred at 60°, while the best performance occurred at 45° and 90° at small ReDc and at large ReDc, respectively. From the comparative results, it can be found that the air inlet angle has completely different effects on the comprehensive heat transfer performance for the heat exchangers with different structures.

  11. Automotive absorption air conditioner utilizing solar and motor waste heat

    Science.gov (United States)

    Popinski, Z. (Inventor)

    1981-01-01

    In combination with the ground vehicles powered by a waste heat generating electric motor, a cooling system including a generator for driving off refrigerant vapor from a strong refrigerant absorbant solution is described. A solar collector, an air-cooled condenser connected with the generator for converting the refrigerant vapor to its liquid state, an air cooled evaporator connected with the condenser for returning the liquid refrigerant to its vapor state, and an absorber is connected to the generator and to the evaporator for dissolving the refrigerant vapor in the weak refrigerant absorbant solution, for providing a strong refrigerant solution. A pump is used to establish a pressurized flow of strong refrigerant absorbant solution from the absorber through the electric motor, and to the collector.

  12. Radiant heat test of Perforated Metal Air Transportable Package (PMATP).

    Energy Technology Data Exchange (ETDEWEB)

    Gronewald, Patrick James; Oneto, Robert (Weidlinger Associates, Inc., Los Altos, CA); Mould, John (Weidlinger Associates, Inc., Los Altos, CA); Pierce, Jim Dwight

    2003-08-01

    A conceptual design for a plutonium air transport package capable of surviving a 'worst case' airplane crash has been developed by Sandia National Laboratories (SNL) for the Japan Nuclear Cycle Development Institute (JNC). A full-scale prototype, designated as the Perforated Metal Air Transport Package (PMATP) was thermally tested in the SNL Radiant Heat Test Facility. This testing, conducted on an undamaged package, simulated a regulation one-hour aviation fuel pool fire test. Finite element thermal predictions compared well with the test results. The package performed as designed, with peak containment package temperatures less than 80 C after exposure to a one-hour test in a 1000 C environment.

  13. Quasi-steady-state model of a counter flow air-to-air heat exchanger with phase change

    DEFF Research Database (Denmark)

    Rose, Jørgen; Nielsen, Toke Rammer; Kragh, Jesper;

    2008-01-01

    -exchanger. Developing highly efficient heat-exchangers and strategies to avoid/remove frost formation implies the use of detailed models to predict and evaluate different heat-exchanger designs and strategies. This paper presents a quasi-steady-state model of a counter-flow air-to-air heat-exchanger that takes......Using mechanical ventilation with highly efficient heat-recovery in northern European or arctic climates is a very efficient way of reducing the energy use for heating in buildings. However, it also presents a series of problems concerning condensation and frost formation in the heat...

  14. Heat Treatment of the Photonic Crystal Fiber

    Institute of Scientific and Technical Information of China (English)

    Joo Beom Eom; Seongwoo Yoo; Jinchae Kim; Hokyung Kim; Un-Chul Paek; Byeong Ha Lee

    2003-01-01

    We report heat treatment of the photonic crystal fiber. As the temperature was increased, the transmission of the photonic crystal fiber was increased, unlike conventional single mode fiber. The transmission increase at short wavelength region was larger than long wavelength region for the various temperatures. After crystallization of the silica glass, the spectra of the photonic crystal fiber were just decreased at all wavelength regions, but, in case of the single mode fiber, the absorption in visible region around 450 nm increased with increasing temperature.

  15. Effect of heat treatment and heat-to-heat variations in the fatigue-crack growth response of Alloy 718

    International Nuclear Information System (INIS)

    The fatigue-crack growth behavior of seven heats of Alloy 718 was studied at five different test temperatures. These seven heats represented at least four different producers, four different product forms, two melt practices, and most of the heat were tested in two different heat-treated conditions. Heat-to-heat variations were noted; these were most obvious in material given the conventional heat-treatment. 8 figs., 5 tabs

  16. STUDY AND NUMERICAL SIMULATION OF SOLAR SYSTEM FOR AIR HEATING

    Directory of Open Access Journals (Sweden)

    M. Ghodbane

    2016-01-01

    Full Text Available The use of solar energy in sunny countries, is an effective outil for compensate the lack in the energy, their benefits are not related only to its economic benefits but especially for the environmental protection, so we must find solutions to the problems of pollution. This work is a theoretical study of a solar flat plate collector ; air is used as the heat transfer fluid. In this study, we established in first step the calculation of solar radiation in various sites in Algeria (Adrar, El Oued, Bechar, Biskra and Tamanrasset. The second step is the parameters influence study of the sites and climate on the performance of our collector. The results obtained are encouraging for the use of this type in the heating in the winter, also it can be used in different kinds of drying.

  17. A Computer Simulation of Steady-State Performance of Air-to-Air Heat Pumps; TOPICAL

    International Nuclear Information System (INIS)

    A computer model by which the performance of air-to-air heat pumps can be simulated is described. The intended use of the model is to evaluate analytically the improvements in performance that can be effected by various component improvements. The model is based on a trio of independent simulation programs originated at the Massachusetts Institute of Technology Heat Transfer Laboratory. The three programs have been combined so that user intervention and decision making between major steps of the simulation are unnecessary. The program was further modified by the authors by substituting a new compressor model and adding a capillary tube model, both of which are described. Performance predicted by the computer model is shown to be in reasonable agreement with performance data observed in our laboratory. Planned modifications by which the utility of the computer model can be enhanced in the future are described. User instructions and a FORTRAN listing of the program are included

  18. Computer simulation of steady-state performance of air-to-air heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, R D; Creswick, F A

    1978-03-01

    A computer model by which the performance of air-to-air heat pumps can be simulated is described. The intended use of the model is to evaluate analytically the improvements in performance that can be effected by various component improvements. The model is based on a trio of independent simulation programs originated at the Massachusetts Institute of Technology Heat Transfer Laboratory. The three programs have been combined so that user intervention and decision making between major steps of the simulation are unnecessary. The program was further modified by substituting a new compressor model and adding a capillary tube model, both of which are described. Performance predicted by the computer model is shown to be in reasonable agreement with performance data observed in our laboratory. Planned modifications by which the utility of the computer model can be enhanced in the future are described. User instructions and a FORTRAN listing of the program are included.

  19. [Treatment of syphilis with malaria or heat].

    Science.gov (United States)

    Verhave, J P

    2016-01-01

    Until the end of the Second World War, syphilis was a common sexually transmitted infection. This stigmatising infectious disease caused mental decline, paralysis and eventually death. The history of syphilis was given public attention because of 'malaria therapy', which had been applied from the First World War onwards in patients with paralytic dementia. In 1917, the Austrian physician Julius Wagner-Jauregg (1857-1940) induced fever in these patients by infecting them with malaria parasites; in 1927, he received the Nobel Prize for his discovery of the healing properties of malarial fever. One source, not cited anywhere, is an interview that the American bacteriologist and science writer/medical journalist Paul de Kruif conducted with Wagner-Jauregg in 1930. The reporting of this meeting, and De Kruif's later involvement in the mechanical heat treatment of patients with syphilis, form the inspiration for this article. When penicillin became available, both treatments became obsolete. PMID:27165455

  20. Multistage heat treatment for super alloys

    International Nuclear Information System (INIS)

    Nickel base alloys of the type γ/γ' are dealt with containing localized regions of low-melting components. The Ni based complex superalloys developed for high demands (temperature, mechanical stressing) are subject to increasing segregation following casting when solidifying. The method compared to previous known processes improves the homogenization of the cast pieces by a special thermal treatment. It is based on diffusion to change the composition of the segregated regions in order to raise their melting point. This can be normally up to 1700C below the melting point of the alloy mixture. Sofar known methods are based on the removal of these segregated regions. The present method does not essentially influence the actual amount (part volume) of these regions, but changes its composition by thermal treatment of 2 to 20 h. in a temperature region of maximum 550C (preferably 300C) below the melting temperature of the entectic. The melting point of the entectic thus rises to a temperature of at least 100C above the γ'solubility curve. A second heat treatment is performed in order to dissolve the γ'-particles occuring in the cast having a particle size of 2-5μm. It takes place at a temperature above that of the γ' solubility curve but below that of the raised temperature of melt start. About 1-10 h are sufficient for practically complete dissolving of the γ'-material. Cooling down to room temperature is carried out at such a rate as to prevent the formation of coarse γ'-particles. Following the invented heat treatment, the particle size of the γ'-phase is of the order of less than 1μm. (IHOE)

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

    International Nuclear Information System (INIS)

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

  2. Quality management in heat treatment process

    Directory of Open Access Journals (Sweden)

    M.T. Roszak

    2013-05-01

    Full Text Available Purpose: The purpose of this paper is to present the specifications of the CQI Heat Treat System Assessment, together with a discussion of the importance, development, implementation and use of this specification. An analysis of the quality management system of the selected organization was performed, which takes care of the thermo-chemical treatment-nitriding, as regards to the specification AIAG CQI-9. The study was carried out to compare the standards based on the scope of the organization covered by individual standards and their hierarchy, where the levels are adequate for the scope of the quality management system.Design/methodology/approach: An assessment of the compliance with the requirements of the CQI-9 based on the criteria closed in the documentation of the specification was performed, by evaluated according to the requirements imposed by the CQI-9, and determining the compliance of the quality system with the requirements determined in the documentation of the specification, with the subscription in the documentation.Findings: As a result of the audit of the nitriding process of selected part of the technology in relation to the requirements of the CQI-9 specification, the deficiencies were identified in relation to the requirements of the CQI-9 specification, and suggestions for their solutions were provided.Research limitations/implications: The paper presents the steps and how to verify the quality management system in the process of heat treatment.Practical implications: The result of the audit specifications CQI-9 detected non-compliance to requirements of the specification. The improvement of the quality management system, with some recommendations, allows to target the activities of the process to the needs and expectations of customers.Originality/value: The paper presents some requirements concerning the quality of the selected part of the thermo-chemical treatment process.

  3. Airborne Asbestos Exposures from Warm Air Heating Systems in Schools.

    Science.gov (United States)

    Burdett, Garry J; Dewberry, Kirsty; Staff, James

    2016-01-01

    The aim of this study was to investigate the concentrations of airborne asbestos that can be released into classrooms of schools that have amosite-containing asbestos insulation board (AIB) in the ceiling plenum or other spaces, particularly where there is forced recirculation of air as part of a warm air heating system. Air samples were collected in three or more classrooms at each of three schools, two of which were of CLASP (Consortium of Local Authorities Special Programme) system-built design, during periods when the schools were unoccupied. Two conditions were sampled: (i) the start-up and running of the heating systems with no disturbance (the background) and (ii) running of the heating systems during simulated disturbance. The simulated disturbance was designed to exceed the level of disturbance to the AIB that would routinely take place in an occupied classroom. A total of 60 or more direct impacts that vibrated and/or flexed the encapsulated or enclosed AIB materials were applied over the sampling period. The impacts were carried out at the start of the sampling and repeated at hourly intervals but did not break or damage the AIB. The target air volume for background samples was ~3000 l of air using a static sampler sited either below or ~1 m from the heater outlet. This would allow an analytical sensitivity (AS) of 0.0001 fibres per millilitre (f ml(-1)) to be achieved, which is 1000 times lower than the EU and UK workplace control limit of 0.1 f ml(-1). Samples with lower volumes of air were also collected in case of overloading and for the shorter disturbance sampling times used at one site. The sampler filters were analysed by phase contrast microscopy (PCM) to give a rapid determination of the overall concentration of visible fibres (all types) released and/or by analytical transmission electron microscopy (TEM) to determine the concentration of asbestos fibres. Due to the low number of fibres, results were reported in terms of both the calculated

  4. Treatment and disposal of steam generator and heat exchanger chemical cleaning wastes

    International Nuclear Information System (INIS)

    Wet air oxidation was effective in reducing the organic loading of Ontario Hydro's EDTA-based steam generator cleaning wastes and the organic acid formulation used for heat exchanger chemical cleaning. Destruction of the complexing agents resulted in direct precipitation of iron from the waste steam generator magnetite solvent and from the heat exchanger cleaning waste. The oxidized liquors contain lower molecular weight organic acids, ammonia and amines, suitable for secondary biological treatment. The oxidized copper waste requires further treatment to reduce dissolved copper levels prior to biological digestion. A preliminary evaluation of UV and ozone degradation of these wastes showed less promise than wet air oxidation. 24 refs., 1 fig., 4 tabs

  5. On the different regimes of gas heating in air plasmas

    Science.gov (United States)

    Pintassilgo, Carlos D.; Guerra, Vasco

    2015-10-01

    Simulations of the gas temperature in air (N2-20%O2) plasma discharges are presented for different values of the reduced electric field, E/N g, electron density n e, pressure and tube radius. This study is based on the solutions to the time-dependent gas thermal balance in a cylindrical geometry coupled to the electron, vibrational and chemical kinetics, for E/{{N}\\text{g}}=50 and 100 Td (1 Td = 10-17 V cm2), 109  ⩽  n e  ⩽  1011 cm-3, pressure in the range 1-20 Torr, and also considering different tube radius, 0.5, 1 and 1.5 cm. The competing role of different gas heating mechanisms is discussed in detail within the time range 0.01-100 ms. For times below 1 ms, gas heating occurs from O2 dissociation by electron impact through pre-dissociative excited states, e + O2  →  e + \\text{O}2*   →  e + 2O(3P) and …  →  e + O(3P) + O(1D), as well as through the quenching of N2 electronically excited states by O2. For longer times, simulation results show that gas heating comes from processes N(4S) + NO(X)  →  N2(X, v ~ 3) + O, N2(A) + O  →  NO(X) + N(2D), V-T N2-O collisions and the recombination of oxygen atoms at the wall. Depending on the given E/N g and n e values, each one of these processes can be an important gas-heating channel. The contribution of V-T N2-O exchanges to gas heating is important in the analysis of the gas temperature for different pressures and values of the tube radius. A global picture of these effects is given by the study of the fraction of the discharge power spent on gas heating, which is always ~15%. The values for the fractional power transferred to gas heating from vibrational and electronic excitation are also presented and discussed.

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

    Directory of Open Access Journals (Sweden)

    Lerchai Yodrak

    2010-01-01

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

  7. Operation technology of air treatment system in nuclear facilities

    CERN Document Server

    Chun, Y B; Hwong, Y H; Lee, H K; Min, D K; Park, K J; Uom, S H; Yang, S Y

    2001-01-01

    Effective operation techniques were reviewed on the air treatment system to protect the personnel in nuclear facilities from the contamination of radio-active particles and to keep the environment clear. Nuclear air treatment system consisted of the ventilation and filtering system was characterized by some test. Measurement of air velocity of blowing/exhaust fan in the ventilation system, leak tests of HEPA filters in the filtering, and measurement of pressure difference between the areas defined by radiation level were conducted. The results acquired form the measurements were reflected directly for the operation of air treatment. In the abnormal state of virus parts of devices composted of the system, the repairing method, maintenance and performance test were also employed in operating effectively the air treatment system. These measuring results and techniques can be available to the operation of air treatment system of PIEF as well as the other nuclear facilities in KAERI.

  8. Heat Engineering and Economical Justification of Selection of Optimum Air Heating Temperature in Recuperators of Heating Continuous Furnaces at Machine-Building Enterprises

    Directory of Open Access Journals (Sweden)

    V. I. Timoshpolsky

    2009-01-01

    Full Text Available The paper presents a methodology for calculation of recuperative heat exchangers applied at heating continuous furnaces of press-forging production at machine-building enterprises. Technical and economic calculations of an optimum air heating temperature have been made taking needle-shape heat exchangers in the RUE MAZ heating continuous  furnaces as an example while varying furnace capacity, cost of power carriers and heat-exchange devices.

  9. 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...

  10. 49 CFR 179.200-11 - Postweld heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.200-11 Section 179.200-11 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... Postweld heat treatment. When specified in § 179.201-1, after welding is complete, postweld heat...

  11. Similarity of coupled heat and mass transfer between air-water and air-liquid desiccant direct-contact systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiao-Hua; Jiang, Yi [Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084 (China); Li, Zhen [Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China)

    2009-12-15

    Packed-bed heat and mass transfer devices are widely used in air-conditioning systems, such as cooling tower, evaporative cooler of air-water direct-contact devices, dehumidifier and regenerator of air-liquid desiccant direct-contact devices. Similarities of heat and mass transfer characteristics between air-water and air-liquid desiccant devices are considered and investigated in this paper. Same reachable handling region of outlet air can be obtained for both air-water and air-liquid desiccant devices, which is among three boundary lines, isenthalpic line of inlet air, iso-relative humidity line of inlet fluid (water or desiccant), and the connecting line of inlet statuses of air and fluid. Inlet conditions of air and fluid affect heat and mass transfer characteristics to some extent, so that a zonal method is proposed only according to the relative statuses of inlet air to inlet fluid. Four zones, dehumidification zones A, D and regeneration zones B, C, are divided for air-desiccant direct-contact devices. The first three zones A, B and C are divided for air-water direct-contact devices, with the same zonal properties as those of air-desiccant devices. In order to obtain better humidification performance, fluid should be heated (in zone C) rather than air (in zone B). And fluid should be cooled (in zone A) rather than air (in zone D) to obtain better dehumidification performance. Counter-flow pattern should be applied for best mass transfer performance in the same conditions within the recommended zone A or C, while parallel-flow pattern is the best in zone B or D. (author)

  12. Air source absorption heat pump in district heating: Applicability analysis and improvement options

    International Nuclear Information System (INIS)

    Highlights: • Applicability of air source absorption heat pump (ASAHP) district heating is studied. • Return temperature and energy saving rate (ESR) in various conditions are optimized. • ASAHP is more suitable for shorter distance or lower temperature district heating. • Two options can reduce the primary return temperature and improve the applicability. • The maximum ESR is improved from 13.6% to 20.4–25.6% by compression-assisted ASAHP. - Abstract: The low-temperature district heating system based on the air source absorption heat pump (ASAHP) was assessed to have great energy saving potential. However, this system may require smaller temperature drop leading to higher pump consumption for long-distance distribution. Therefore, the applicability of ASAHP-based district heating system is analyzed for different primary return temperatures, pipeline distances, pipeline resistances, supplied water temperatures, application regions, and working fluids. The energy saving rate (ESR) under different conditions are calculated, considering both the ASAHP efficiency and the distribution consumption. Results show that ASAHP system is more suitable for short-distance district heating, while for longer-distance heating, lower supplied hot water temperature is preferred. In addition, the advantages of NH3/H2O are inferior to those of NH3/LiNO3, and the advantages for warmer regions and lower pipeline resistance are more obvious. The primary return temperatures are optimized to obtain maximum ESRs, after which the suitable distances under different acceptable ESRs are summarized. To improve the applicability of ASAHP, the integration of cascaded heat exchanger (CHX) and compression-assisted ASAHP (CASAHP) are proposed, which can reduce the primary return temperature. The integration of CHX can effectively improve the applicability of ASAHP under higher supplied water temperatures. As for the utilization of CASAHP, higher compression ratio (CR) is better in longer

  13. Pressurized heat treatment of glass ceramic

    Science.gov (United States)

    Kramer, D.P.

    1984-04-19

    A method of producing a glass-ceramic having a specified thermal expansion value is disclosed. The method includes the step of pressurizing the parent glass material to a predetermined pressure during heat treatment so that the glass-ceramic produced has a specified thermal expansion value. Preferably, the glass-ceramic material is isostatically pressed. A method for forming a strong glass-ceramic to metal seal is also disclosed in which the glass-ceramic is fabricated to have a thermal expansion value equal to that of the metal. The determination of the thermal expansion value of a parent glass material placed in a high-temperature environment is also used to determine the pressure in the environment.

  14. Cast construction elements for heat treatment furnaces

    Directory of Open Access Journals (Sweden)

    B. Piekarski

    2011-07-01

    Full Text Available The study presents sketches and photos of the cast creep-resistant components used in various types of heat treatment furnaces. The shape of the elements results from the type of the operation carried out in the furnace, while dimensions are adjusted to the size of the furnace working chamber. The castings are mainly made from the high-alloyed, austenitic chromium-nickel or nickel-chromium steel, selecting the grade in accordance with the furnace operating conditions described by the rated temperature, the type and parameters of the applied operating atmosphere, and the charge weight. Typical examples in this family of construction elements are: crucibles, roller tracks, radiant tubes and guides. The majority of castings are produced in sand moulds.

  15. Phase Transformations during the Reaction Heat Treatment

    CERN Document Server

    Scheuerlein, C; Thilly, L; Buta, F; Peng, X; Gregory, E; Parrell, J A; Pong, I; Bordini, B; Cantoni, M

    2009-01-01

    The evolution of Nb containing phases during the diffusion heat treatment of three different high critical current Nb3Sn strand types is compared, based on synchrotron X-ray diffraction results that have been obtained at the ID15 beam line of the European Synchrotron Radiation Facility (ESRF). In all strands studied, Nb3Sn formation is preceded by the formation of a Cu-Nb-Sn ternary phase, NbSn2 and Nb6Sn5. As compared to the PIT and Tube Type strand, the amount of these phases formed in the RRP strand is relatively small. In the RRP strand subelements with a fine filament structure Nb3Sn grows more quickly, thereby preventing to a large extent the formation of the other higher tin phases.

  16. Heat treatment of refractory metals in vacuum

    International Nuclear Information System (INIS)

    Generalized is the outcome of the research, carried out in the KFTI of the Ukraine Academy of Sciences, in which metals are freed from the admixtures. Mainly the physical and chemical processes, taking place in the ''metal-gas'' systems, have been studied. The content of gas and carbon in metals have been researched by the methods of chemical analysis; microhardness has been measured. The constants of the crystalline lattice and of the surface phases have been studied by the X-ray structure analysis. The gas partial pressure, their liberation and absorption rates have been measured using the mass-spectrometry method. The coefficients of the hydrogen diffusion in molybdenum and tungsten at 1.000-1.800 deg C have been determined. The oxidation activation energy for Mo and W has been determined as equal to 12.8 and 21.1 Kcal/mol O2, respectively. The carbide formation on the surface is the basic reason for the embrittlement of Mo and W following the vacuum annealing. At low pressure the oxidation of V, Nb and Ta reaches its maximum at 1.600 deg C. This is stipulated by the competing diffusion and adsorption stages of the absorption process. Above 2.000 deg C de-oxidation is observed. Heat treatment of Nb in vacuum during the inleakage of O2 and N2 is conducive to strengthening, particularly during testing in the region of 300 deg C and 500 deg C. The coefficients of the O and N adhesion onto Zr at 900-1.600 deg C amount to 0.47-0.94 and 0.01-0.1, respectively. Absorption of gases during heat-treatment in vacuum strengthens Zr and changes its structure

  17. Reduced heat stress in offices in the tropics using solar powered drying of the supply air

    DEFF Research Database (Denmark)

    Gunnarsen, Lars; Santos, A M B

    2002-01-01

    Many solutions to indoor climate problems known from developed countries may have prohibitive installation and running costs in developing countries. The purpose was to develop a low-cost solution to heat stress in a hot and humid environment based on solar powered drying of supply air. Dry supply...... air may facilitate personal cooling by increased evaporation of sweat. Heat acclimatized people with efficient sweating may in particular benefit from this cooling. A prototype solar powered supply system for dried-only air was made. Air from the system was mixed with room air, heated to six different...... content of room air, temperature of supply air and moisture content of supply air was developed based on the experiments. Reduction of moisture content in the supply air by 1.6 g/kg had the same effect as lowering the operative temperature by 1 degree C. The solar-powered system for supplying dry air...

  18. 8th International Symposium on Heating, Ventilation and Air Conditioning

    CERN Document Server

    Zhu, Yingxin; Li, Yuguo; Vol.1 Indoor and Outdoor Environment; Vol.2 HVAC&R Component and Energy System; Vol.3 Building Simulation and Information Management

    2014-01-01

    Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning is based on the 8th International Symposium of the same name (ISHVAC2013), which took place in Xi’an on October 19-21, 2013. The conference series was initiated at Tsinghua University in 1991 and has since become the premier international HVAC conference initiated in China, playing a significant part in the development of HVAC and indoor environmental research and industry around the world. This international conference provided an exclusive opportunity for policy-makers, designers, researchers, engineers and managers to share their experience. Considering the recent attention on building energy consumption and indoor environments, ISHVAC2013 provided a global platform for discussing recent research on and developments in different aspects of HVAC systems and components, with a focus on building energy consumption, energy efficiency and indoor environments. These categories span a broad range of topics, and the proce...

  19. EFFECT OF HEAT TREATMENT ON THE CHANGE IN COLOR

    Directory of Open Access Journals (Sweden)

    Vu Manh Tuong

    2010-04-01

    Full Text Available Acacia hybrid (Acacia mangium x auriculiformis, a wood species of low dimensional stability which is used almost exclusively for pulp, paper, or as firewood, was heat treated in nitrogen at 210-230 ºC for 2 to 6 hours. The changes in color and anti-swelling efficiency (ASE of wood after heat treatment were determined for the different heat treatment conditions. The results show that heat treatment mainly resulted in the darkening of wood tissues, and heat-treated wood had better dimensional stability than those of the control samples. Chemical modifications of wood components were determined by FT-IR analysis. Spectra indicated that the hydroxyl group content was reduced by increased treatment intensity. This result coincides with the increase in dimensional stability of heat-treated wood. Heat treatment of acacia hybrid wood shows an interesting potential to improve the quality and value for solid wood products from plantation-grown wood species.

  20. Analysis of the Thermodynamical Efficiency of an Air Handling Unit with a Heat Pump

    OpenAIRE

    Vytautas Martinaitis; Paulius Bareika; Violeta Misevičiūtė

    2012-01-01

    This paper evaluates the seasonal thermodynamic efficiency of the air-to-air heat pump used for a heat recovery ventilation system and several modulations of compressors affecting the thermodynamic efficiency of the heat pump. A variable speed and on/off-type compressors have been selected. In order to evaluate the thermodynamic potential of the device, energy analysis has been performed. Along with modelling the operation of the air handling unit during the cold time of the year, variations ...

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

    OpenAIRE

    Chen Yan; Zhang Yufeng

    2013-01-01

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

  2. HEAT OF COMPRESSION AND OPPORTUNITY OF ITS USE FOR INCREASE OF EFFICIENCY OF AIR SEPARATION PLANTS

    OpenAIRE

    Лавренченко, Г. К.; Швец, С. Г.; Копытин, А. В.

    2015-01-01

    The analysis of possible directions useful utilization of heat of compression for production of the cold water in the heat-utilizing refrigerating machine and for organization heating vacuum regeneration of the adsorbent bloc of the desiccation and the purification of the air. Mark expediency of the application absorption lithium bromide refrigerating machines for organization preliminary cooling of the air in the air separation plant large productivity.

  3. Theoretical energy saving analysis of air conditioning system using heat pipe heat exchanger for Indian climatic zones

    Directory of Open Access Journals (Sweden)

    T.S. Jadhav

    2015-12-01

    Full Text Available Heat pipe heat exchanger (HPHX is an excellent device used for heat recovery in air conditioning systems. The Energy Conservation Building Code (ECBC – Bureau of Energy Efficiency (BEE India classifies Indian climatic zones into five categories viz., Hot and Dry (e.g. Ahmedabad, Jodhpur etc, Warm and Humid (e.g. Mumbai, Chennai etc, Composite (e.g. Nagpur, Jaipur etc, Cold (e.g. Guwahati etc and Temperate (e.g. Bengaluru etc. The literature review indicated that very limited information is available on annual energy saving analysis of air conditioning system with HPHX for Indian climatic zones. The paper investigates the possible energy savings using HPHX for heat recovery in air conditioning system for Indian climatic zones. The analysis is carried out for total 25 Indian cities representing different climatic zones. The analysis is performed for a 6 row HPHX and assuming outdoor air quantity as 1 m3/s, return air dry bulb temperature as 23 °C and compressor power as 1 kW/TR. This paper discusses the use of HPHX only for the heat recovery application (exchange of sensible heat between fresh outdoor air and conditioned return air. The annual energy savings with HPHX for a particular city is calculated for number of hours when outdoor air dry bulb temperature exceeds 25 °C. The maximum energy saving potential is revealed for hot and dry, warm and humid and composite Indian climatic zones.

  4. Experimental and numerical investigation of a cross flow air-to-water heat pipe-based heat exchanger used in waste heat recovery

    OpenAIRE

    J. Ramos; Chong, A.; Jouhara, H

    2016-01-01

    This paper applies CFD modelling and numerical calculations to predict the thermal performance of a cross flow heat pipe based heat exchanger. The heat exchanger under study transfers heat from air to water and it is equipped with six water-charged wickless heat pipes, with a single-pass flow pattern on the air side (evaporator) and two flow passes on the water side (condenser). For the purpose of CFD modelling, the heat pipes were considered as solid devices of a known thermal conductivity w...

  5. Design and Fabrication of Serpentine Tube Type Sodium to Air Heat Exchangers for PFBR SGDHR Circuits

    International Nuclear Information System (INIS)

    Prototype Fast Breeder Reactor (PFBR) is a 500MWe pool type, sodium cooled nuclear reactor which is in advanced stage of construction by BHAVINI at Kalpakkam, India. The sodium to air heat exchanger (AHX) in the safety grade decay heat removal (SGDHR) loop transfers heat from the intermediate circuit sodium to atmospheric air by natural convection. As the operating temperature is high and AHX forms part of reactor SGDHR system, the boundaries of the AHX must possess a high degree of reliability against failure. This is achieved by comprehensive design, precise material selection, high standard quality control and quality assurance during manufacturing. The major material of construction of AHX is Modified 9Cr-1Mo steel (N&T). AHX has straight sodium inlet and outlet headers with 116 nos. of hot formed pullouts on its surface having OD38.1mmX2.6mm thickness which are connected to a finned tube bundle. Due to the many hot formed pullouts on the headers and complex geometry, the welding sequence, heat treatment and non-destructive examinations of the welds is an extremely difficult and challenging task. Various special tooling and fixtures were designed and developed for the manufacture of the AHXs. This paper provides details of the salient design aspects, challenges, innovations and success achieved during hot forming, welding and fabrication activities of the serpentine tube type AHXs for 500MWe Prototype Fast Breeder Reactor. (author)

  6. 49 CFR 179.100-10 - Postweld heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.100-10 Section 179...-10 Postweld heat treatment. (a) After welding is complete, steel tanks and all attachments welded... treatment is prohibited. (c) Tank and welded attachments, fabricated from ASTM A 240/A 240M (IBR, see §...

  7. Urban heat island and linkage with air quality

    International Nuclear Information System (INIS)

    The urban heat island (UHI) effect can be noticed in cities where the temperature is higher than the surrounding countryside, on average 2 deg. C above. In summer during a heat wave, the gap can up to over ten-degree. UHI causes a thermal stress which induces some repercussions on health. The formation of UHI is more and more documented but further studies have to be conducted in order to qualify and quantify the impacts on our health and environment, and the link with atmospheric pollution. Studies have shown air quality deterioration in UHI areas: Both phenomena can be simultaneous because their conditions of appearance are often linked. Henceforth the stake is to manage and if possible reduce UHI to adapt cities to the expected climate change. Dense cities in the future will also have to be naturally cooled down. In order to do so, we will have to act on the most influential UHI formation factors, namely: vegetation and water, buildings (shapes and materials), production and consumption of energy. (authors)

  8. Air Conditioning in cold region and utilization of heat pump. Kanchi no danreibo to heat pump riyo

    Energy Technology Data Exchange (ETDEWEB)

    Ochifuji, N. (Hokkaido University, Sapporo (Japan). Faculty of Engineering)

    1990-02-02

    Hokkaido and Tohoku District being about four times and two times, respectively as large as all Japan in average quantity of fuel, used for the air heating, the buildings there, as structured thermally insulated and aerially tightened, must be of a high quality environment with ventilation, aerial cleanness, etc. From the viewpoint that the heat pump, as able to utilize the low density energy,is appropriate exactly for the air heating in such a cold district, the heat pump was introduced in principle, categories and characteristics, problems of thermal source, and recent topics. With highness in temperature level of existing thermal source and lowness in that of air heating, the heat pump is thermodynamically explainable to be high in coefficient of performance (ratio of added quantity of heat on the high temperature side to the input power from the exterior). It is therefore the most important to maintain high quantity thermal sources, generally such as air, water, soil and waste water. Artificial waste heat is thermal source, the most noticeable as that in the cold region for the future. For example, local air conditioning system, utilizing waste heat from the subway operation, in Sapporo Station is taken notice of for its worldwidely first materialization. 21 refs., 21 figs., 6 tabs.

  9. Device with Complex System for Heat Utilization and Reduction of Hazardous Air Emissions

    OpenAIRE

    O. Kascheeva; E. Voronov; V. Kascheev; I. Zhidovich; V. Sorokin; O. Klimenkova

    2014-01-01

    Investigations concern heat utilization and reduction of hazardous emissions occurring in residential buildings and accompanying operation of a great number of industrial enterprises in particular heat and power objects, and firstly, heat-generating units of small power located in densely populated residential areas without centralized heat supply.The investigation target is to reduce cost of heat produced by independent system of building heat supply, reduction of air pollution  due to hazar...

  10. Modeling of an Air Conditioning System with Geothermal Heat Pump for a Residential Building

    OpenAIRE

    Silvia Cocchi; Sonia Castellucci; Andrea Tucci

    2013-01-01

    The need to address climate change caused by greenhouse gas emissions attaches great importance to research aimed at using renewable energy. Geothermal energy is an interesting alternative concerning the production of energy for air conditioning of buildings (heating and cooling), through the use of geothermal heat pumps. In this work a model has been developed in order to simulate an air conditioning system with geothermal heat pump. A ground source heat pump (GSHP) uses the shallow ground a...

  11. Study on high heat flux cooling by air-water flow driven by high speed air flow

    International Nuclear Information System (INIS)

    The effect of air injection into a subcooled water flow on boiling heat transfer and a critical heat flux (CHF) was examined experimentally. Experiments were conducted in the range of subcooling of 50 K, a superficial velocity of water and air Ul = 0,17 3,4 and Ug= 0 15,2 m/s, respectively. A test heat transfer surface was a 5 mm wide, 40 mm long and 0,2 mm thick stainless steel sheet embedded on the bottom wall of a 10 mm high and 20 mm wide rectangular flow channel. Nine times enhancement of the heat transfer in the non-boiling region was attained at the most by introducing an air flow into a water single-phase flow. The heat transfer augmentation in the non-boiling region was attained by less power increase than that in the case that only the water flow rate was increased. From the aspect of the power consumption and the heat transfer enhancement, the small air introduction in the low water flow rate region seemed more profitable, although the air introduction in the high water flow rate region and also the large air introduction were still effective in the augmentation of the heat transfer in the non-boiling region. (author)

  12. Heat Treatment of Die and Mould Oriented Concurrent Design

    Institute of Scientific and Technical Information of China (English)

    LI Xiong; ZHANG Hong-bing; RUAN Xue-yu; LUO Zhong-hua; ZHANG Yan

    2006-01-01

    Many disadvantages exist in the traditional die design method which belongs to serial pattern. It is well known that heat treatment is highly important to the dies. A new idea of concurrent design for heat treatment process of die and mould was developed in order to overcome the existent shortcomings of heat treatment process. Heat treatment CAD/CAE was integrated with concurrent circumstance and the relevant model was built. These investigations can remarkably improve efficiency, reduce cost and ensure quality of R and D for products.

  13. Quasi-steady-state model of a counter-flow air-to-air heat-exchanger with phase change

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Joergen; Nielsen, Toke Rammer; Kragh, Jesper; Svendsen, Svend [Department of Civil Engineering, Technical University of Denmark, Brovej, Building 118, DK-2800 Kgs. Lyngby (Denmark)

    2008-05-15

    Using mechanical ventilation with highly efficient heat-recovery in northern European or arctic climates is a very efficient way of reducing the energy use for heating in buildings. However, it also presents a series of problems concerning condensation and frost formation in the heat-exchanger. Developing highly efficient heat-exchangers and strategies to avoid/remove frost formation implies the use of detailed models to predict and evaluate different heat-exchanger designs and strategies. This paper presents a quasi-steady-state model of a counter-flow air-to-air heat-exchanger that takes into account the effects of condensation and frost formation. The model is developed as an Excel spreadsheet, and specific results are compared with laboratory measurements. As an example, the model is used to determine the most energy-efficient control strategy for a specific heat-exchanger under northern European and arctic climate conditions. (author)

  14. Evaluation of heat exchange performance for air-cooler in HTTR

    International Nuclear Information System (INIS)

    In High Temperature Engineering Test Reactor (HTTR) of 30MW, the generated heat at reactor core is finally dissipated at the air-cooler (ACL) by way of the heat exchangers of the primary pressurized water cooler and the intermediate heat exchanger. To remove generated hear at reactor core and to hold reactor inlet coolant temperature to specified temperature, heat exchangers in main cooling system of HTTR should have designed heat exchange performance. In this report, heat exchange performance for ACL in main cooling system is evaluated with previous operation data, and evaluated values are compared with designed value. Moreover, heat exchange performance at full power operation is estimated for the air temperature. As the result, ACL has heat exchange performance removing generated heat at reactor core under the ACL inlet air temperature of 33 degC. (author)

  15. Experimental investigation on the photovoltaic-thermal solar heat pump air-conditioning system on water-heating mode

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Guiyin; Hu, Hainan; Liu, Xu [Department of Physics, Nanjing University, Nanjing 210093 (China)

    2010-09-15

    An experimental study on operation performance of photovoltaic-thermal solar heat pump air-conditioning system was conducted in this paper. The experimental system of photovoltaic-thermal solar heat pump air-conditioning system was set up. The performance parameters such as the evaporation pressure, the condensation pressure and the coefficient of performance (COP) of heat pump air-conditioning system, the water temperature and receiving heat capacity in water heater, the photovoltaic (PV) module temperature and the photovoltaic efficiency were investigated. The experimental results show that the mean photovoltaic efficiency of photovoltaic-thermal (PV/T) solar heat pump air-conditioning system reaches 10.4%, and can improve 23.8% in comparison with that of the conventional photovoltaic module, the mean COP of heat pump air-conditioning system may attain 2.88 and the water temperature in water heater can increase to 42 C. These results indicate that the photovoltaic-thermal solar heat pump air-conditioning system has better performances and can stably work. (author)

  16. Dual Phase Heat Treatment of Low-Alloy Steel

    Institute of Scientific and Technical Information of China (English)

    HAN Jian-min; CUI Shi-hai; LI Wei-jing; MA Xiao-yan

    2005-01-01

    Dual phase heat treatment is an economical and effective way for improving the properties of low carbon steels and low-alloy steel materials. In this paper, the microstructures and mechanical properties of 20MnSi steel treated by different dual phase heat treatment have been studied. The results show that dual phase heat treatment with pre-quenching technique and then heating from room temperature to the critical zone can achieve finer and more homogeneous microstructure than that with pre-normalizing technique and then cooling from austenite zone to the critical zone. Among all factors affecting dual phase heat treatment, quenching temperature at the critical zone and tempering temperature play an important part in mechanical properties. Using proper dual phase heat treatment technique with computer-optimized parameters, the yield strength, the elongation and impact toughness of 20MnSi can reach 860 MPa, 16% and 207 MPa respectively.

  17. Response of four foliage plants to heated soil and reduced air temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Bodnaruk, W.H. Jr.; Mills, T.W.; Ingram, D.L.

    1981-01-01

    Tip cuttings of Dieffenbachia maculata (Lodd.) G. Donn Exotic Perfection Compacta' and Aglaonema commutatum Schott Silver Queen and single eye cuttings of Epipremnum aureum (Linden and Andre) Bunt, and Philodendron scandens oxycardium (Schott) Bunt. were propagated in combinations of 4 minimum air temperatures, 45/sup 0/, 50/sup 0/, 55/sup 0/ and 60/sup 0/F (7.2/sup 0/, 10/sup 0/, 12.7/sup 0/, 15.5/sup 0/C), and 2 soil temperature treatments; controlled 70/sup 0/F (21/sup 0/C) minimum and variable. Maintaining minimum soil temperatures at 70/sup 0/F reduced production times for rooted Dieffenbachia and Aglaonema tips by 45% and of Epipremnum and Philodendron suitable for 3 inch pots by 35% and 25%, respectively, regardless of minimum air temperature. Minimum air temperature had little effect on Dieffenbachia or Aglaonema root number and length at 70/sup 0/F soil temperature. Similarly shoot length and number of leaves of Philodendron and Epipremnum were not affected by minimum air temperatures with 70/sup 0/F soil temperature. Plant quality was uniformly high in all crops at the 70/sup 0/F soil minimum for all air temperatures except Epipremnum which was chlorotic at 45/sup 0/F. A description of a warm water in-benching heating system is included. 6 references, 2 figures, 9 tables.

  18. The heat treatment of Fermanal cast steel

    Directory of Open Access Journals (Sweden)

    F. Binczyk

    2007-12-01

    Full Text Available The study discloses the results of microstructural examinations, testing of magnetic properties and hardness measurements as cast and after heat treatment conducted on the Fermanal cast steel. A characteristic feature of this cast steel is its density lower by about 10% than the density of carbon cast steel [4]. It has been proved that the factor deciding about the composition of microstructure (fraction of ferrite and austenite is the content of aluminium. The matrix totally austenitic is present in cast steel containing from 0,8 to 0,9% C, from 22 to 24% Mn, and from 4,5 to 5,5% Al. The magnetic properties examined on samples of the Fermanal cast steel were determined by spectroscopy of the Mössbauer effect with isotope 57Fe. The magnetic properties represented by a mean value of the hyperfine magnetic field Bhf and relative magnetic permeability were determined. It has been stated that the level of magnetic properties of the Fermanal cast steel depends on the content of ferrite. The effect of the parameters of solutioning and ageing on the cast steel microstructure and hardness after modification with additions of B, Ti and Nb was investigated.

  19. CLEAN-AIR heat pump. Reduced energy consumption for ventilation in buildings by integrating air cleaning and heat pump. Final Report; CLEAN-AIR heat pump - Reduceret energiforbrug til ventilation af bygninger ved luftrensning integreret med luft varmepumpe. Slut rapport

    Energy Technology Data Exchange (ETDEWEB)

    Fang, L.; Olesen, Bjarne W.; Molinaro, G.; Simmonsen, P.; Skocajic, S. [Danmarks Tekniske Univ. Institut for Byggeri og Anlaeg, Lyngby (Denmark); Hummelshoej, R.M.; Carlassara, L. [COWI A/S, Lyngby, (Denmark); Groenbaek, H.; Hansen, Ole R. [Exhausto A/S, Langeskov (Denmark)

    2011-07-01

    This report summarizes task 1 of the Clean Air Heat Pump project - modelling and simulation on energy savings when using the clean air heat pump for ventilation, air cleaning and energy recovery. The total energy consumption of the proposed ventilation systems using clean air heat pump technology was calculated by a theoretical model and compared with the reference ventilation systems (conventional ventilation systems). The energy compared between the two systems includes energy used for heating, cooling and fan. The simulation and energy saving calculation was made for the application of the clean air heat pump in three typical climate conditions, i.e. mild-cold, mild-hot and hot and wet climates. Real climate data recorded from three cities in 2002 was used for the calculation. The three cities were Copenhagen (Denmark), Milan (Italy) and Colombo (Sir Lanka) which represent the above three typical climate zones. For the Danish climate (the mild cold climate), the calculations show that the ventilation system using clean air heat pump technology can save up to 42% of energy cost in winter compared to the conventional ventilation system. The energy saving in summer can be as high as 66% for the ventilation system with humidity control and 9% for the ventilation system without the requirement of humidity control. Since the Danish summer climate is very mild, over 80% of the yearly energy consumption for ventilation is used during winter season. It is, therefore, estimated that more than 35% annual energy saving for ventilation is expected in Denmark using the clean air heat pump ventilation technology. For the mild hot climate, e.g. the Italian climate, the calculations show that up to 63% of the energy saving can be achieved in summer season. For the winter mode, 17% reduction of the energy cost can be expected for the domestic use. For industrial use, the energy cost of the clean air heat pump may not be favourable due to the industrial price of gas in Italy is

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

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose; Diz, Ruben; Uhia, Francisco J.; Dopazo, Alberto; Ferro, Jose M. [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende No. 9, 36310 Vigo (Spain)

    2011-01-15

    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. (author)

  1. Air pollutants emissions from waste treatment and disposal facilities.

    Science.gov (United States)

    Hamoda, Mohamed F

    2006-01-01

    This study examined the atmospheric pollution created by some waste treatment and disposal facilities in the State of Kuwait. Air monitoring was conducted in a municipal wastewater treatment plant, an industrial wastewater treatment plant established in a petroleum refinery, and at a landfill site used for disposal of solid wastes. Such plants were selected as models for waste treatment and disposal facilities in the Arabian Gulf region and elsewhere. Air measurements were made over a period of 6 months and included levels of gaseous emissions as well as concentrations of volatile organic compounds (VOCs). Samples of gas and bioaerosols were collected from ambient air surrounding the treatment facilities. The results obtained from this study have indicated the presence of VOCs and other gaseous pollutants such as methane, ammonia, and hydrogen sulphide in air surrounding the waste treatment and disposal facilities. In some cases the levels exceeded the concentration limits specified by the air quality standards. Offensive odors were also detected. The study revealed that adverse environmental impact of air pollutants is a major concern in the industrial more than in the municipal waste treatment facilities but sitting of municipal waste treatment and disposal facilities nearby the urban areas poses a threat to the public health. PMID:16401572

  2. Graphene transport properties upon exposure to PMMA processing and heat treatments

    DEFF Research Database (Denmark)

    Gammelgaard, Lene; Caridad, Jose; Cagliani, Alberto;

    2014-01-01

    The evolution of graphene's electrical transport properties due to processing with the polymer polymethyl methacrylate (PMMA) and heat are examined in this study. The use of stencil (shadow mask) lithography enables fabrication of graphene devices without the usage of polymers, chemicals or heat......, allowing us to measure the evolution of the electrical transport properties during individual processing steps from the initial as-exfoliated to the PMMA-processed graphene. Heating generally promotes the conformation of graphene to SiO2 and is found to play a major role for the electrical properties of...... that flakes conforming poorly to the substrate will have a higher carrier mobility which will however be reduced as heat treatment enhance the conformation. We finally show the electrical properties of graphene to be reversible upon heat treatments in air up to 200°C....

  3. A passive decay heat removal system for LWRs based on air cooling

    International Nuclear Information System (INIS)

    Highlights: • A passive decay heat removal system for LWRs is discussed. • An air cooler model which condenses steam is developed. • The decay heat can be removed by air coolers with forced convection. • The dimensions of the air cooler are proposed. - Abstract: The present paper describes the capability of an air cooling system (ACS) to remove decay heat from a core of LWR such as an advanced boiling water reactor (ABWR) and a pressurized water reactor (PWR). The motivation of the present research is the Fukushima severe accident (SA) on 11 March 2011. Since emergency cooling systems using electricity were not available due to station blackout (SBO) and malfunctions, many engineers might understand that water cooling was not completely reliable. Therefore, a passive decay heat removal (DHR) system would be proposed in order to prevent such an SA under the conditions of an SBO event. The plant behaviors during the SBO are calculated using the system code NETFLOW++ for the ABWR and PWR with the ACS. Two types of air coolers (ACs) are applied for the ABWR, i.e., a steam condensing air cooler (SCAC) of which intake for heat transfer tubes is provided in the steam region, and single-phase type of which intake is provided in the water region. The DHR characteristics are calculated under the conditions of the forced air circulation and also the natural air convection. As a result of the calculations, the decay heat can be removed safely by the reasonably sized ACS when heat transfer tubes are cooled with the forced air circulation. The heat removal rate per one finned heat transfer tube is evaluated as a function of air flow rate. The heat removal rate increases as a function of the air flow rate

  4. A passive decay heat removal system for LWRs based on air cooling

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, Hiroyasu, E-mail: mochizki@u-fukui.ac.jp [Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan); Yano, Takahiro [Graduate School of Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga, Fukui 914-0055 (Japan)

    2015-05-15

    Highlights: • A passive decay heat removal system for LWRs is discussed. • An air cooler model which condenses steam is developed. • The decay heat can be removed by air coolers with forced convection. • The dimensions of the air cooler are proposed. - Abstract: The present paper describes the capability of an air cooling system (ACS) to remove decay heat from a core of LWR such as an advanced boiling water reactor (ABWR) and a pressurized water reactor (PWR). The motivation of the present research is the Fukushima severe accident (SA) on 11 March 2011. Since emergency cooling systems using electricity were not available due to station blackout (SBO) and malfunctions, many engineers might understand that water cooling was not completely reliable. Therefore, a passive decay heat removal (DHR) system would be proposed in order to prevent such an SA under the conditions of an SBO event. The plant behaviors during the SBO are calculated using the system code NETFLOW++ for the ABWR and PWR with the ACS. Two types of air coolers (ACs) are applied for the ABWR, i.e., a steam condensing air cooler (SCAC) of which intake for heat transfer tubes is provided in the steam region, and single-phase type of which intake is provided in the water region. The DHR characteristics are calculated under the conditions of the forced air circulation and also the natural air convection. As a result of the calculations, the decay heat can be removed safely by the reasonably sized ACS when heat transfer tubes are cooled with the forced air circulation. The heat removal rate per one finned heat transfer tube is evaluated as a function of air flow rate. The heat removal rate increases as a function of the air flow rate.

  5. 77 FR 8178 - Test Procedures for Central Air Conditioners and Heat Pumps: Public Meeting

    Science.gov (United States)

    2012-02-14

    ... distribution of those central air conditioning systems and heat pump systems manufactured after January 1, 2010, that are designed to use R-22 refrigerant. 74 FR 66450 (Dec. 15, 2009). EPA's rulemaking included an... issued two guidance documents surrounding testing central air conditioner and heat pump systems...

  6. 10 CFR 431.92 - Definitions concerning commercial air conditioners and heat pumps.

    Science.gov (United States)

    2010-01-01

    ... total electric power input, expressed in watt-hours, during the same period. Single package unit means..., when both the cooling (or heating) effect and the net work input are expressed in identical units of measurement. Commercial package air-conditioning and heating equipment means air-cooled,...

  7. Temperature and Humidity Independent Control Research on Ground Source Heat Pump Air Conditioning System

    Science.gov (United States)

    Chen, G.; Wang, L. L.

    Taking green demonstration center building air conditioning system as an example, this paper presents the temperature and humidity independent control system combined with ground source heat pump system, emphasis on the design of dry terminal device system, fresh air system and ground source heat pump system.

  8. Automotive Air Conditioning and Heating; Automotive Mechanics (Advanced): 9047.04.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    This document presents an outline for a 135-hour course designed to provide the student with all the foundations necessary to become employable in the automotive air conditioning and heating trade. The course of study includes an orientation to the world of work, the elementary physics of air conditioning and heating, and laboratory experiments…

  9. Criterion-Referenced Test (CRT) Items for Air Conditioning, Heating and Refrigeration.

    Science.gov (United States)

    Davis, Diane, Ed.

    These criterion-referenced test (CRT) items for air conditioning, heating, and refrigeration are keyed to the Missouri Air Conditioning, Heating, and Refrigeration Competency Profile. The items are designed to work with both the Vocational Instructional Management System and Vocational Administrative Management System. For word processing and…

  10. Forum environmental and energy technology 2013. Power-heat cogeneration and air pollution prevention

    International Nuclear Information System (INIS)

    The volume covers the following topics: The teaching reward 2013 - concept and implementation of the ''Forum environmental and energy technology''; energy efficient air pollution control and material recovery; air pollution control by oxidation; electrical energy production from low-temperature waste heat (ORC processes), electrical power production and process heat utilization.

  11. Heat treatment method for two-phase stainless steel

    International Nuclear Information System (INIS)

    A two-phase stainless steel the toughness of which is reduced by exposure to a high temperature is kept at from 900degC to 1040degC to be solidified and then quenched. With such procedures, a δ-phase deposited in a ferrite phase can be eliminated to restore the toughness. In the solidification step, the two-phase stainless steel having a plate thickness of 1cm or less is kept for 15mins or more, and is kept for additional 5min on every increase of the thickness of 1cm, and then it is compulsorily cooled with water or air. In the heat treatment comprising such steps, a Cr-depleted layer of the welded portion of the two-phase stainless steel of reduced toughness is eliminated to restore an initial state thereby enabling to maintain the integrity of the welded portion. Since the δ-phase deposited in the ferrite phase can be eliminated by solid-solubilizing the two phase stainless steel of reduced toughness by induction heating, reduced toughness can be restored thereby enabling to keep the integrity. (T.M.)

  12. Special methods of anti-corrosion treatment in heat exchangers

    International Nuclear Information System (INIS)

    An anti-corrosion treatment must be adapted to the design of the heat exchanger and the conditions under which it is used. It is often the case, therefore, that highly specialized solutions are found. For the tubular heat exchanger, an organic coating has frequently proved suitable. The results obtained are determined by the construction, the surface characteristics of the components and paying attention to the risk of blister formation. With water-cooled condensers, cleaning of the tubes while the equipment is running has proved successful. It alleviates the corrosion problem and assists the action of the inhibitors. Equipment made from materials such as titanium and austenitic CrNi steels, which are capable of being passivated, can frequently be retained in a passive state by adding air to the corrosive medium. In such cases, the excessive corrosion would normally necessitate the use of an expensive material. Where damage is caused by gaps and dead spaces it is not always possible to find a constructional remedy. A well-devised construction can subsequently be decisively influenced by manufacturing techniques relating to the structure, the state of internal stress or the surface condition. (orig./GSCH)

  13. Determination of air side heat transfer coefficient in a mini-channel heat exchanger using Wilson Plot method

    International Nuclear Information System (INIS)

    In this study, the air side heat transfer coefficient of an aluminium mini-channel heat exchanger was investigated for single-phase flow in the mini-channel, with water in the tubes and air on the outside. Research methods included hydraulic tests on a single mini-channel tube, Wilson Plot experiments and experiment validation. Results obtained from the hydraulic test showed that turbulent flow occurred in the tube at a Reynolds number of 830. Wilson Plot experiments were conducted to determine air side heat transfer coefficient of the heat exchanger. The tube side Reynolds number was maintained above 1000 to ensure turbulent flow and tube side heat transfer coefficient was calculated using Gnielinski equation for turbulent flow. The air side heat transfer coefficients obtained from the Wilson Plot experiments were in good agreement with known correlations. The outcome of this study is to use the air side heat transfer coefficient to calculate the performance of refrigerant condensers for different tube pass ratios and flow pass configurations

  14. Development of a System Identification Model for an Air Source Heat Pump

    OpenAIRE

    Han, Dong Won; Chang, Youngsoo; Kim, Seo Young; Kim, Yongchan

    2012-01-01

    Heat pump system can save energy and installation cost and reduces CO2 emissions. In this study, a system identification of an air source heat pump system using R410A with a variable speed compressor was experimentally investigated under various ambient and indoor temperature and cooling or heating capacity. The experimental study was also performed under cold and hot climate conditions as well as normal ambient temperature in cooling and heating mode. A heat pump system was installed and tes...

  15. Control Techniques in Heating, Ventilating and Air Conditioning Systems

    Directory of Open Access Journals (Sweden)

    H. Mirinejad

    2008-01-01

    Full Text Available Problem statement: Heating, Ventilating and Air Conditioning (HVAC systems are among the main installations in residential, commercial and industrial buildings. The purpose of the HVAC systems is normally to provide a comfortable environment in terms of temperature, humidity and other environmental parameters for the occupants as well as to save energy. Achieving these objectives requires a suitable control system design. Approach: In this overview, thermal comfort level and ISO comfort field is introduced, followed by a review and comparison of the main existing control techniques used in HVAC systems to date. Results: The present overview shows that intelligent controllers which are based on the human sensation of thermal comfort have a better performance in providing thermal comfort as well as energy saving than the traditional controllers and those based on a model of the HVAC system. Conclusion: Such an overview provides an insight into current control methods in HVAC systems and can help scholars and HVAC learners to have the comprehensive information about a variety of control techniques in the field of HVAC and therefore to better design a proper controller for their work

  16. Investigation of anodic oxide coatings on zirconium after heat treatment

    International Nuclear Information System (INIS)

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment

  17. Investigation of anodic oxide coatings on zirconium after heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Maciej [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Dercz, Grzegorz [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty Street 1 A, 41-500 Chorzów (Poland); Suchanek, Katarzyna [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego Street 152, 31-342 Krakow (Poland); Simka, Wojciech, E-mail: wojciech.simka@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland)

    2015-08-15

    Highlights: • Oxide layers prepared via PEO of zirconium were subjected to heat treatment. • Surface characteristics were determined for the obtained oxide coatings. • Heat treatment led to the partial destruction of the anodic oxide layer. • Pitting corrosion resistance of zirconium was improved after the modification. - Abstract: Herein, results of heat treatment of zirconium anodised under plasma electrolytic oxidation (PEO) conditions at 500–800 °C are presented. The obtained oxide films were investigated by means of SEM, XRD and Raman spectroscopy. The corrosion resistance of the zirconium specimens was evaluated in Ringer's solution. A bilayer oxide coatings generated in the course of PEO of zirconium were not observed after the heat treatment. The resulting oxide layers contained a new sublayer located at the metal/oxide interface is suggested to originate from the thermal oxidation of zirconium. The corrosion resistance of the anodised metal was improved after the heat treatment.

  18. Researches Regarding the Efficiency of Water to Air Heat Exchanger with Heat Pipes for the Mechanical Ventilation System

    Directory of Open Access Journals (Sweden)

    Andrei Burlacu

    2007-01-01

    Full Text Available The present paper proposes the analysis of the efficiency of water to air heat exchanger with heat pipes for the mechanical ventilation system. The performed study is based on the necessity of the unconventional energy forms capitalization, increasing of the energy efficiency and the energy consumption decrease in concordance with the sustainable development concept.

  19. Researches Regarding the Efficiency of Water to Air Heat Exchanger with Heat Pipes for the Mechanical Ventilation System

    OpenAIRE

    Andrei Burlacu; Theodor Mateescu

    2007-01-01

    The present paper proposes the analysis of the efficiency of water to air heat exchanger with heat pipes for the mechanical ventilation system. The performed study is based on the necessity of the unconventional energy forms capitalization, increasing of the energy efficiency and the energy consumption decrease in concordance with the sustainable development concept.

  20. DISSOLVED AIR FLOTATION TREATMENT OF GULF SHRIMP CANNERY WASTEWATER

    Science.gov (United States)

    This study reports on the operation of a plant scale dissolved air flotation system installed to define and evaluate attainable shrimp cannery wastewater treatment levels. The system was operated in all three modes of DAF pressurization. Destabilizing coagulants investigation inc...

  1. Measured Performance of a Low Temperature Air Source Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    R.K. Johnson

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.

  2. Crystallization Analysis and Control of Ammonia-Based Air Source Absorption Heat Pump in Cold Regions

    OpenAIRE

    Wu, Wei; Wang, Baolong; Shi, Wenxing; Li, Xianting

    2013-01-01

    Energy consumption of heating and domestic hot water is very high and will keep increasing. Air source absorption heat pump (ASAHP) was proposed to overcome the problems of low energy efficiency and high air pollution existing in boiler systems, as well as the problem of bad performance under low ambient temperatures for electrical heat pumps. In order to investigate the crystallization possibility of ammonia-salt ASAHP, crystallization margin (evaluated by solution mass concentration) at gen...

  3. Effect of heat treatment on domain-wall pinning sites in magnetic garnet films

    International Nuclear Information System (INIS)

    The effect of heat treatment in air atmosphere was investigated on an epitaxially grown magnetic garnet film. The value of the uniaxial anisotropy field decreased by the annealing, but its exponential increase with decreasing temperature was not affected. The annealing up to 1200 deg. C had practically no influence on other magnetic parameters, including the domain-wall pinning field, HP, and its temperature dependence. The fact that HP is independent of the heat treatment, in spite of the strong annealing dependence of the anisotropy field values, was explained by the appropriate modification of the characteristic parameters of the defects systems present in the sample

  4. Cold Heat Release Characteristics of Solidified Oil Droplet-Water Solution Latent Heat Emulsion by Air Bubbles

    Science.gov (United States)

    Inaba, Hideo; Morita, Shin-Ichi

    The present work investigates the cold heat-release characteristics of the solidified oil droplets (tetradecane, C14H30, freezing point 278.9 K)/water solution emulsion as a latent heat-storage material having a low melting point. An air bubbles-emulsion direct-contact heat exchange method is selected for the cold heat-results from the solidified oil droplet-emulsion layer. This type of direct-contact method results in the high thermal efficiency. The diameter of air bubbles in the emulsion increases as compared with that in the pure water. The air bubbles blown from a nozzle show a strong mixing behavior during rising in the emulsion. The temperature effectiveness, the sensible heat release time and the latent heat release time have been measured as experimental parameters. The useful nondimensional emulsion level equations for these parameters have been derived in terms of the nondimensional emalsion level expressed the emulsion layer dimensions, Reynolds number for air flow, Stefan number and heat capacity ratio.

  5. Conjugate Heat Transfer Analysis of an Ultrasonic Molten Metal Treatment System

    Institute of Scientific and Technical Information of China (English)

    ZHU Youli; BIAN Feilong; WANG Yanli; ZHAO Qian

    2014-01-01

    In piezoceramic ultrasonic devices, the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material. While the end of the horn usually serves near the melting point of the molten metal and is enclosed in an airtight chamber, so that it is difficult to experimentally measure the temperature of the transducer and its variation with time, which bring heavy difficulty to the design of the ultrasonic molten metal treatment system. To find a way out, conjugate heat transfer analysis of an ultrasonic molten metal treatment system is performed with coupled fluid and heat transfer finite element method. In modeling of the system, the RNG model and the SIMPLE algorithm are adopted for turbulence and nonlinear coupling between the momentum equation and the energy equation. Forced air cooling as well as natural air cooling is analyzed to compare the difference of temperature evolution. Numerical results show that, after about 350 s of working time, temperatures in the surface of the ceramic stacks in forced air cooling drop about 7 K compared with that in natural cooling. At 240 s, The molten metal surface emits heat radiation with a maximum rate of about 19 036 W/m2, while the heat insulation disc absorbs heat radiation at a maximum rate of about 7922 W/m2, which indicates the effectiveness of heat insulation of the asbestos pad. Transient heat transfer film coefficient and its distribution, which are difficult to be measured experimentally are also obtained through numerical simulation. At 240 s, the heat transfer film coefficient in the surface of the transducer ranges from -17.86 to 20.17 W/(m2•K). Compared with the trial and error method based on the test, the proposed research provides a more effective way in the design and analysis of the temperature control of the molten metal treatment system.

  6. Reduced heat stress in offices in the tropics using solar powered drying of the supply air

    Energy Technology Data Exchange (ETDEWEB)

    Gunnarsen, L. [By og Byg. Statens Byggeforskningsinstitut, Hoersholm (Denmark); Santos, A.M.B. [Univ. of the Philippines, Diliman (Philippines)

    2002-07-01

    Many solutions to indoor climate problems known from developed countries may have prohibitive installation and running costs in developing countries. The purpose was to develop a low-cost solution to heat stress in a hot and humid environment based on solar powered drying of supply air. Dry supply air may facilitate personal cooling by increased evaporation of sweat. Heat acclimatized people with efficient sweating may in particular benefit from this cooling. A prototype solar powered supply system for dried-only air was made. Air from the system was mixed with room air, heated to six different combinations of temperature and humidity and led to Personal Units for Ventilation and Cooling (PUVAC) in six cubicles simulating office workplaces. A total of 123 heat acclimatized subjects were exposed 45 min in each of the cubicles. A model for the combined effect of operative temperature of room, moisture content of room air, temperature of supply air and moisture content of supply air was developed based on the experiments. Reduction of moisture content in the supply air by 1.6 g/kg had the same effect as lowering the operative temperature by 1deg C. The solar-powered system for supplying dry air is a low-cost alternative to traditional air conditioning in hot and humid regions. (au)

  7. Reduced heat stress in offices in the tropics using solar powered drying of the supply air.

    Science.gov (United States)

    Gunnarsen, L; Santos, A M B

    2002-12-01

    Many solutions to indoor climate problems known from developed countries may have prohibitive installation and running costs in developing countries. The purpose was to develop a low-cost solution to heat stress in a hot and humid environment based on solar powered drying of supply air. Dry supply air may facilitate personal cooling by increased evaporation of sweat. Heat acclimatized people with efficient sweating may in particular benefit from this cooling. A prototype solar powered supply system for dried-only air was made. Air from the system was mixed with room air, heated to six different combinations of temperature and humidity and led to Personal Units for Ventilation and Cooling (PUVAC) in six cubicles simulating office workplaces. A total of 123 heat acclimatized subjects were exposed 45 min in each of the cubicles. A model for the combined effect of operative temperature of room, moisture content of room air, temperature of supply air and moisture content of supply air was developed based on the experiments. Reduction of moisture content in the supply air by 1.6 g/kg had the same effect as lowering the operative temperature by 1 degree C. The solar-powered system for supplying dry air is a low-cost alternative to traditional air conditioning in hot and humid regions. PMID:12532757

  8. Norwegian households' perception of wood pellet stove compared to air-to-air heat pump and electric heating

    International Nuclear Information System (INIS)

    In 2003, the high dependency on electric heating combined with the high electricity price prompted a significant number of Norwegian households to consider alternative heating systems. The government introduced economic support for wood pellet heating and heat pumps. In contrast to the fast growing heat pump market, this financial support has not resulted in a widespread adoption of wood pellet heating. This paper studies factors that influence the choice of heating system based on Norwegian households' perceptions. Electric heating, heat pump and wood pellet heating were compared, with a special focus on wood pellet heating. This study was conducted as a questionnaire survey on two independent samples. The first sample consisted of 188 randomly chosen Norwegian households, mainly using electric heating; the second sample consisted of 461 households using wood pellet heating. Our results show that socio-demographic factors, communication among households, the perceived importance of heating system attributes, and the applied decision strategy all influence the Norwegian homeowners. The significance of these factors differs between the two samples and the preferred type of anticipated future heating system. Strategies for possible interventions and policy initiatives are discussed.

  9. Norwegian households' perception of wood pellet stove compared to air-to-air heat pump and electric heating

    International Nuclear Information System (INIS)

    In 2003, the high dependency on electric heating combined with the high electricity price prompted a significant number of Norwegian households to consider alternative heating systems. The government introduced economic support for wood pellet heating and heat pumps. In contrast to the fast growing heat pump market, this financial support has not resulted in a widespread adoption of wood pellet heating. This paper studies factors that influence the choice of heating system based on Norwegian households' perceptions. Electric heating, heat pump and wood pellet heating were compared, with a special focus on wood pellet heating. This study was conducted as a questionnaire survey on two independent samples. The first sample consisted of 188 randomly chosen Norwegian households, mainly using electric heating; the second sample consisted of 461 households using wood pellet heating. Our results show that socio-demographic factors, communication among households, the perceived importance of heating system attributes, and the applied decision strategy all influence the Norwegian homeowners. The significance of these factors differs between the two samples and the preferred type of anticipated future heating system. Strategies for possible interventions and policy initiatives are discussed. (author)

  10. Norwegian households' perception of wood pellet stove compared to air-to-air heat pump and electric heating

    Energy Technology Data Exchange (ETDEWEB)

    Sopha, Bertha Maya; Hertwich, Edgar G. [Industrial Ecology Programme, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Kloeckner, Christian A. [Department of Psychology, Section for Risk Psychology, Environment and Safety (RIPENSA), Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Skjevrak, Geir [Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

    2010-07-15

    In 2003, the high dependency on electric heating combined with the high electricity price prompted a significant number of Norwegian households to consider alternative heating systems. The government introduced economic support for wood pellet heating and heat pumps. In contrast to the fast growing heat pump market, this financial support has not resulted in a widespread adoption of wood pellet heating. This paper studies factors that influence the choice of heating system based on Norwegian households' perceptions. Electric heating, heat pump and wood pellet heating were compared, with a special focus on wood pellet heating. This study was conducted as a questionnaire survey on two independent samples. The first sample consisted of 188 randomly chosen Norwegian households, mainly using electric heating; the second sample consisted of 461 households using wood pellet heating. Our results show that socio-demographic factors, communication among households, the perceived importance of heating system attributes, and the applied decision strategy all influence the Norwegian homeowners. The significance of these factors differs between the two samples and the preferred type of anticipated future heating system. Strategies for possible interventions and policy initiatives are discussed. (author)

  11. Heat treatment modelling using strongly continuous semigroups.

    Science.gov (United States)

    Malek, Alaeddin; Abbasi, Ghasem

    2015-07-01

    In this paper, mathematical simulation of bioheat transfer phenomenon within the living tissue is studied using the thermal wave model. Three different sources that have therapeutic applications in laser surgery, cornea laser heating and cancer hyperthermia are used. Spatial and transient heating source, on the skin surface and inside biological body, are considered by using step heating, sinusoidal and constant heating. Mathematical simulations describe a non-Fourier process. Exact solution for the corresponding non-Fourier bioheat transfer model that has time lag in its heat flux is proposed using strongly continuous semigroup theory in conjunction with variational methods. The abstract differential equation, infinitesimal generator and corresponding strongly continuous semigroup are proposed. It is proved that related semigroup is a contraction semigroup and is exponentially stable. Mathematical simulations are done for skin burning and thermal therapy in 10 different models and the related solutions are depicted. Unlike numerical solutions, which suffer from uncertain physical results, proposed analytical solutions do not have unwanted numerical oscillations. PMID:25912988

  12. Ultrasonic evaluation of heat treatment for stress relief in steel

    International Nuclear Information System (INIS)

    Residual stresses in materials arise due to the manufacturing processes. As a consequence, in the nuclear area some components must suffer a stress relief treatment according to strict criteria. Although these treatments are carefully carried on, concern with nuclear safety is constantly growing. This work proposes a nondestructive ultrasonic method to guarantee the efficiency of the heat treatment. It was used a short peened steel plate with tensile and compressive stresses which was submitted to a stress relief treatment. The results show that the proposed ultrasonic method could be used to confirm the efficiency of the stress relief heat treatment. (author)

  13. Effect of heat treatment on carbon steel pipe welds

    International Nuclear Information System (INIS)

    The heat treatment to improve the altered properties of carbon steel pipe welds is described. Pipe critical components in oil, gasification and nuclear reactor plants require adequate room temperature toughness and high strength at both room and moderately elevated temperatures. Microstructure and microhardness across the welds were changed markedly by the welding process and heat treatment. The presentation of hardness fluctuation in the welds can produce premature failure. A number of heat treatments are suggested to improve the properties of the welds. (author) 8 figs., 5 refs

  14. Air-sea and oceanic heat flux contributions to the heat budget of the northern Gulf of Alaska shelf

    Science.gov (United States)

    Janout, Markus A.; Weingartner, Thomas J.; Stabeno, Phyllis J.

    2013-04-01

    We constructed annual cycles of National Centers for Environmental Prediction air-sea fluxes and temporal oceanic heat content change from Seward Line hydrographic surveys to quantify the different contributions to the oceanic heat budget within the Alaska Coastal Current (ACC) on the northern Gulf of Alaska shelf. The deficit between air-sea fluxes and the temporal change in oceanic heat content throughout the cooling season (October-April) varies from ~40 to 110 W m-2 and is balanced by ocean heat flux convergence. Cross-shelf heat flux convergence is insignificant on annual average, and the nearshore heat budget is likely entirely balanced by the ACC, which resupplies ~15%-50% of the heat removed by air-sea fluxes during the cooling season. Furthermore, we estimated spatial heat flux gradients and conclude that air-sea fluxes increase from east to west and from offshore to onshore. The cross-shore gradients are governed by wind speed gradients, likely due to ageostrophic nearshore wind events during the cooling season, while the along-shelf heat flux gradients are governed by the occurrence of low-pressure systems in the northern GOA that result in cold northerly winds over the northwestern GOA. These results underline the ACC's role as the dominant oceanic heat source to the northern GOA shelf and further imply an increased cooling rate of the ACC west of the Seward Line. Furthermore, our analysis showed that nearshore regions, particularly waters in the ACC, are subjected to stronger winter cooling than the middle and outer shelves.

  15. Influence of Cooling to Heating Load Ratio on Optimal Supply Water and Air Temperatures in an Air Conditioning System

    Science.gov (United States)

    Karino, Naoki; Shiba, Takashi; Yokoyama, Ryohei; Ito, Koichi

    In planning an air conditioning system, supply water and air temperatures are important factors from the viewpoint of energy saving and cost reduction. For example, lower temperature supply water and air for space cooling reduce the coefficient of performance of a refrigeration machine, and increase the thickness of heat insulation material. However, they enable larger temperature differences, and reduce equipment sizes and power demand. It is also an important subject to evaluate the effect of the supply water and air temperatures on energy saving and cost reduction on the annual basis by considering not only cooling but also heating loads. The purposes of this paper are to propose an optimal planning method for an air conditioning system with large temperature difference, and to analyze the effect of supply water and air temperatures on the long-term economics through a numerical study for an office building. As a result, it is shown that the proposed method effectively determines supply water and air temperatures, and the influence of the cooling to heating load ratio on the long-term economics is clarified.

  16. Relief of Residual Stress and Estimation of Heat-Treatment Characteristics for Al6061 Alloy by Cryogenic Heat Treatment

    International Nuclear Information System (INIS)

    The purpose of this study is to relieve the residual stress of Al6061 using cryogenic heat treatment. Experimental T6 and cryogenic heat treatments were carried out to define the convective heat-transfer coefficient, which was then applied in the finite-element method (FEM) to predict the residual stress. The predicted residual stress was compared with the residual stress measured by X-ray diffraction (XRD), and the results were in good agreement. The mechanical properties were estimated by measuring the electrical conductivity and hardness. In addition, the size and formation of the precipitations were observed by TEM and XRD analysis for both T6 and cryogenic heat treatments. The effects of the cryogenic heat treatment on the residual stress, mechanical properties, and precipitation of Al6061 alloys were thus confirmed

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-15

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

  18. Natural convection heat transfer from a long heated vertical cylinder to an adjacent air gap of concentric and eccentric conditions

    DEFF Research Database (Denmark)

    Hosseini, R.; Kolaei, Alireza Rezania; Alipour, M.; Rosendahl, Lasse

    2012-01-01

    In this work, the natural convection heat transfer from a long vertical electrically heated cylinder to an adjacent air gap is experimentally studied. The aspect and diameter ratios of the cylinder are 55.56 and 6.33, respectively. The experimental measurements were obtained for a concentric...... condition and six eccentricities from 0.1 to 0.92 at five different heat fluxes. The surface temperature of the heated rod is measured at different heights, and the Nusselt number is calculated at the temperature measurement locations. A correlation is suggested to determine the Nusselt number based on the...

  19. Development of a Bench-Top Air-to-Water Heat Pump Experimental Apparatus

    OpenAIRE

    H. I. Abu-Mulaweh

    2009-01-01

    A bench-top air-to-water heat pump experimental apparatus was designed,developed, and constructed for instructional and demonstrative purposes. Thisair-to-water heat pump experimental apparatus is capable of demonstratingthermodynamics and heat transfer concepts and principles. This heat pumpexperimental setup was designed around the vapor compression refrigerationcycle. This experimental apparatus has an intuitive user interface, reliable, safefor student use, and portable. The interface is ...

  20. Heat pump air conditioning system for pure electric vehicle at ultra-low temperature

    OpenAIRE

    Li Hai-Jun; Zhou Guang-Hui; Li An-Gui; Li Xu-Ge; Li Ya-Nan; Chen Jie

    2014-01-01

    When the ordinary heat pump air conditioning system of a pure electric vehicle runs at ultra-low temperature, the discharge temperature of compressor will be too high and the heating capacity of the system will decay seriously, it will lead to inactivity of the heating system. In order to solve this problem, a modification is put forward, and an experiment is also designed. The experimental results show that in the same conditions, this new heating system i...

  1. Clean heating surfaces - a condition for a fuel consumption decrease (air heaters)

    International Nuclear Information System (INIS)

    Unclean heating surface from the water and the flame side has an influence on the exit gas temperature after combustion. That can be noticed from the gas temperature increase, which is a basic indication of the heating surface condition. Unavoidable, the heating surface has to be clean to get a more economical work of the unit. In this paper the means of cleaning air heater heating surfaces from the flame side are given. (author). 2 tabs., 1 fig

  2. Effect of specimen geometry on heat transfer coefficient of rubber to air

    OpenAIRE

    Pongdhorn Sae-oui

    2000-01-01

    It is widely known that the heat transfer coefficient is not material specific but, on the contrary, it depends on several factors such as surface appearance, suface emissivity, fluid velocity and specimen geometry. In this study, the effect of geometry on heat transfer coefficient of rubber to air was investigated. Determination of heat transfer coefficient was undertaken by an indirect method, namely Finite Element Analysis (FEA). With this method, the best value of heat transfer coefficien...

  3. Characteristics of exhaust air facades as solar absorbers for saving of heating energy

    Science.gov (United States)

    Voncube, H. L.; Ludwig, E.

    1982-12-01

    The solar radiation exploited by solar exhaust air windows was measured at a building facing four main directions. The windows were not constructed as optimal radiation absorbers and the heat gain stood in a range of 3 to 10% of the heat consumption, depending on time of year. Optimal windows (chiefly clear glass with Venetian blinds) were found by a computer program simulating the process of radiation in an exhaust air-window and heat gains up to 50% can be obtained. Relation to air flow rate and others were found. The calculated results were proved by measurements. With a suitable heating systems in the building (heat transport form south side to north side, heat storage) up to 50% of the annual consumption can be saved.

  4. Low GWP Refrigerants Modelling Study for a Room Air Conditioner Having Microchannel Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Bhandari, Mahabir S [ORNL

    2016-01-01

    Microchannel heat exchangers (MHX) have found great successes in residential and commercial air conditioning applications, being compact heat exchangers, to reduce refrigerant charge and material cost. This investigation aims to extend the application of MHXs in split, room air conditioners (RAC), per fundamental heat exchanger and system modelling. For this paper, microchannel condenser and evaporator models were developed, using a segment-to-segment modelling approach. The microchannel heat exchanger models were integrated to a system design model. The system model is able to predict the performance indices, such as cooling capacity, efficiency, sensible heat ratio, etc. Using the calibrated system and heat exchanger models, we evaluated numerous low GWP (global warming potential) refrigerants. The predicted system performance indices, e.g. cooling efficiency, compressor discharge temperature, and required compressor displacement volume etc., are compared. Suitable replacements for R22 and R-410A for the room air conditioner application are recommended.

  5. Air and liquid solar heating system with heatpump, VP-SOL

    DEFF Research Database (Denmark)

    Kristiansen, Finn Harken; Jensen, Søren Østergaard

    1998-01-01

    For more than a year, measurements have been made on an air/fluid solar heating system with heat pump. The annual thermal performance of the system has been found and compared with simulations carried out by means of the simulation program KVIKSOL.The heat loss of the hot water tank is calculated.......The sensor of the differential control of the fluid pump is placed inappropriately. Hereby the fluid part performs about 5% less.The air through the solar collectors is controlled by the difference between the room temperature and the solar collector temperature. The air differential control should be...

  6. Examination of heat treatments at preservation of grape must

    Directory of Open Access Journals (Sweden)

    Péter Korzenszky

    2014-02-01

    Full Text Available Heat treatment is a well-known process in food preservation. It is made to avoid and to slow down food deterioration. The process was developed by Louise Pasteur French scientist to avoid late among others wine further fermentation. The different heat treatments influence the shelf life in food production. In our article we present the process of grape must fermentation, as grape must is the base material of wine production. The treatment of harvested fresh grape juice has a big influence on end product quality. It is our experiments we examined the same grape must with four different methods in closed and in open spaces to determine CO2 concentration change. There are four different methods for treatment of grape juice: boiling, microwave treatment, treatment by water bath thermostat and a control without treatment. As a result of the comparison it can be stated that the heat treatment delays the start of fermentation, thereby increasing shelf life of grape must. However, no significant differences were found between two fermentation of heat-treated grape must by the microwave and water-bath thermostat. The different heat treatment of grape must base materials was done at the laboratory in Faculty of Mechanical Engineering of Szent István University. The origin of the table grapes used for the examination was Gödöllő-hillside. Normal 0 21 false false false HU X-NONE X-NONE

  7. Dynamic interactions between the ground heat exchanger and environments in earth–air tunnel ventilation of buildings

    OpenAIRE

    Gan, Guohui

    2014-01-01

    Earth–air tunnel ventilation is an energy efficient method of preheating or cooling of supply air to abuilding. The purposes of this study are to investigate the performance of earth–air heat exchangersunder varying soil and atmosphere conditions and the interactions between the heat exchanger andenvironments. A computer program has been developed for simulation of the thermal performance of anearth–air heat exchanger for preheating and cooling of supply air, taking account of dynamic variati...

  8. The effect of air leakage and heat exchange on the decay of entrapped air pocket slamming oscillations

    Science.gov (United States)

    Abrahamsen, Bjørn C.; Faltinsen, Odd M.

    2011-10-01

    The phenomenon studied in this work is that of an air pocket entrapped by a free surface water wave inside a rectangular tank at a high filling level. The wave, which is a gravity wave, is caused by forced horizontal motion which is constructed in a particular way, in order to entrap an air pocket as it approaches the upper left corner of the tank. As the wave touches the roof, the air is compressed and starts to oscillate. The oscillations resemble, to some extent, the free oscillations of an underdamped mass-spring system, where the mass is related to the generalized added mass effect of the water pressure associated with the air pocket oscillations. The stiffness is due to the compressibility of the air. The reason for the damping or, more generally, the decay of the air pocket oscillations is less understood. Air leakage has been proposed as one possible reason for this decay. In this work, the role of air leakage is found not to be the reason for the decay of the air pocket oscillations, because it is not present during major parts of the impact. However, by drilling holes in the roof of the tank, the effect of leakage during the oscillations is proven to cause decay. To explain the physical source of the decay of the oscillations, damping due to heat transfer to and from the air pocket is investigated through an analytical one-dimensional steady-state model. The damping due to heat transfer is observed to play an important role. The obtained understanding of the mechanisms causing the decay of the air-pocket impact at the upper corner is believed to be relevant to other types of impacts, particularly the entrapment of air pockets on walls by breaking waves.

  9. A new heating system based on coupled air source absorption heat pump for cold regions: Energy saving analysis

    International Nuclear Information System (INIS)

    Highlights: • A double-stage coupled air source absorption heat pump (ASAHP) is proposed. • The coupled ASAHP exhibits stable and high performance in very cold regions. • Energy-saving rate of the coupled ASAHP in all the typical cities is above 20%. - Abstract: Energy consumption for heating and domestic hot water is very high. The heating system based on an air source absorption heat pump (ASAHP) had been assessed to have great energy saving potential. However, the single-stage ASAHP exhibits poor performance when the outdoor air temperature is very low. A double-stage coupled ASAHP is proposed to improve the energy-saving potential of single-stage ASAHP in cold regions. The heating capacity and primary energy efficiency (PEE) of the proposed system operated in both coupled mode and single-stage mode are simulated under various working conditions. The building load and primary energy consumption of different heating systems applied in cold regions are analyzed comparatively to investigate the energy-saving potential of the coupled ASAHP. Results show that the coupled ASAHP exhibits stable PEE and provides high heating capacity in very cold conditions. The energy-saving rate of the coupled ASAHP in all the typical cities is above 20%. In addition, the energy-saving potential of the single-stage ASAHP in severely cold areas can be improved obviously by coupled ASAHP, with an improvement of 7.73% in Harbin

  10. Heat-treatment-induced luminescence degradation in Tb3+-doped CePO4 nanorods

    International Nuclear Information System (INIS)

    CePO4:Tb nanorods were synthesized via a simple wet-chemical route. The as-synthesized CePO4:Tb nanorods present high photoluminescence efficiency due to an efficient energy transfer form Ce3+ to Tb3+. However, heat treatment at 150 deg. C in air leads to a significant decrease of photoluminescence. X-ray photoelectron spectroscopy and excitation spectra revealed the oxidation of Ce3+ to Ce4+ in the heat-treatment process, which should be responsible for significant photoluminescence degradation due to the breakage of Ce3+→Tb3+ energy transfer. This conclusion is further supported by atmosphere and size effects of photoluminescence of CePO4:Tb under the heat treatment.

  11. Examination of the influence of heat treatment on the properties of Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Vuksanovic, D.; Rakocevic, S. [Faculty of Metallurgy, Podgorica (RS); Markovic, S. [Faculty of Technology and Metallurgy, Belgrade (RS); Petrovic, T. [Institute ' Kirilo Savic' , Belgrade (RS); Kovacevic, K. [Institute for Ferrous Metallurgy (RS); Tripkovic, S. [H.K. Petar Drapsin, Mladenovac (RS)

    2007-08-15

    In this paper the influence of heat treatment on the structural and mechanical properties of Al-Si alloys was investigated. Silicon content in the examined alloys was in the range 11 to 14%, the contents of the other alloying elements were in the standard range but all alloys were modified with strontium. The regime of the applied heat treatment was quenching (520 C/6h - cooling in water) + aging (205oC/7h - air cooling). The examinations were carried out at room temperature as well as at 250 C and 300 C. The obtained results showed a positive influence of the applied heat treatment on the mechanical properties of the examined alloys. The improvement of the mechanical properties can be considered as a consequence of a redistribution and change of morphology of the phases present in the structure of the alloys. (orig.)

  12. Protection of phosphatidylcholine to photosystemⅡ membrane during heat treatment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Photosystem Ⅱ membrane was reconstituted with phosphatidylcholine (PC) with different kinds of fatty acyl chains and the protection of PC to photosystem Ⅱ (PSⅡ) membrane during heat treatment was investigated using oxygen electrode, variable fluorescence and circular dichroism (CD) spectroscopy. Heat treatment decreased the oxygen evolution rate and the F′v/Fm′ ratio of PSⅡ membrane and influenced CD spectra of PSⅡ membrane, but PC inhibited the effect of heat treatment on the oxygen evolution rate, the F′v/F′m ratio and CD spectra of PSⅡ membrane. The results indicate that PC can protect PSⅡ membrane against heat treatment and the alterations in the unsaturated fatty acid extent in PC can cause the changes of the protection ability.

  13. Effect of heat treatment on high strength aluminium silicon alloy

    International Nuclear Information System (INIS)

    To improve the mechanical properties of domestically manufactured motor cycle pistons, the modification of structure by heat treatment has been studied. Pistons were subjected to different heat treatment cycles and optimum parameters were determined. Optical microscopic techniques and mechanical testing have been employed to study the effect of heat treatment o the microstructure and mechanical properties. A comparison of the properties of the domestically manufactured and imported pistons has also been made. Aluminum Silicon based alloys have been widely used for the production of automobile pistons due to their promising features like low coefficient of thermal expansion, high strength and favorable tribological characteristics. These properties can be further modified by alloying and heat treatment. (author)

  14. Influence of the convective surface transfer coefficients on the Heat, Air, and Moisture (HAM) building performance

    DEFF Research Database (Denmark)

    Steskens, Paul Wilhelmus Maria Hermanus; Janssen, Hans; Rode, Carsten

    2009-01-01

    Current models to predict heat, air and moisture (HAM) conditions in buildings assume constant boundary conditions for the temperature and relative humidity of the neighbouring air and for the surface heat and moisture transfer coefficients. These assumptions may introduce errors in the predicted...... HAM conditions. The paper focuses on the influence of the interior surface heat and moisture transfer coefficients, and investigates its effect on the hygrothermal performance. The parameter study showed that the magnitude of the convective surface transfer coefficients have a relatively large...... influence on the predicted hygrothermal conditions at the surface of a building component and on the heat and vapour exchange with the indoor environment....

  15. Experimental investigations of the sodium/air heat exchanger with natural draught chimney for the EFR

    International Nuclear Information System (INIS)

    In a first series of experiments in the new large sodium experimental plant ILONA, the post-shutdown heat removal system for the European Fast Breeder Reactor EFR developed by Interatom and working by natural convection was tested. The air-side flow in the heat exchanger and chimney was optimized in extensive model experiments and the results were taken into account in the construction of the Na/air heat exchanger in the ILONA. A considerable increase in output was achieved, compared to the design, based on the flow model experiments for the ILONA heat exchanger. (orig.)

  16. Dynamic models of heating and cooling coils with one-dimensional air distribution

    Science.gov (United States)

    Wang, Zijie; Krauss, G.

    1993-06-01

    This paper presents the simulation models of the plate-fin, air-to-water (or water vapour) heat exchangers used as air-heating or air-cooling and dehumidifying coils in the HVAC (Heating, Ventilation and Air-Conditioning) systems. The thermal models are used to calculate the heat exchange between distributing air and coil pipes and outlet temperatures of air and heat or chilled fluid. The aerodynamic models are used to account for the pressure drop of the air crossing the coil tubes. They can also be used to optimize the structures of such coils. The models are based on principal laws of heat and mass conservation and fluid mechanics. They are transparent and easy to use. In our work, a coil is considered as an assembly of numbers of basic elements in which all the state variables are unique. Therefore we can conveniently simulate the coils with different structures and different geometric parameters. Two modular programs TRNSYS (Transient System Simulation) and ESACAP are utilized as supporting softwares which make the programming and simulation greatly simplified. The coil elements and a real coil were simulated. The results were compared with the data offered by the manufacturer (company SOFICA) and also with those obtained using critical methods such as NTU method, etc. and good agreement is attained.

  17. Numerical Simulation and Experimental Studies of Air Treatment Process with Water Spray of One Row Parallel Flow

    Institute of Scientific and Technical Information of China (English)

    倪波

    2001-01-01

    The main purpose of the present work is to make a further insight into the procedure of heat and mass transfer between water droplets sprayed and air stream in a direct evaporative air cooler used in air-conditioning system in textile mills. The thermodynamic models of the two-phase flow in such a air treatment system have been developed for one row parallel flow spray.The fields of temperature and relative humidity in spraylchamber, as well as the trajectories of sprayed drops have been obtained by calculation. A series of experiment aiming at quantifying the system performance and its influence factors have been conducted. It indicates that the increases of air velocity and water/air ratio while the decrease of nozzle density are favorable. Finally, the comparison between numerical simulation and experimental results have been carried out. Good agreements have been found for outlet air temperaturewhile a maximum error of 10% has been observed for air relative humidity.

  18. TOUGHNESS AND HEAT TREATMENT. RELATIONSHIP IN A 2091 ALUMINIUM ALLOY

    OpenAIRE

    Hautefeuille, L.; Rahouadj, R.; Barbaux, Y.; Clavel, M.

    1987-01-01

    The 2091 alloy was tested to determine toughness levels with respect to heat treatment. A drastic decrease in fracture toughness was observed as a function of heat treatment. The occurence of such a toughness drop was clearly related to fracture modes : . Transgranular and intergranular precipitation and deformation modes were studied. The loss of grain boundary strength could be explained by the precipitation of the quasi crystalline phase T2

  19. An intelligent manufacturing system for heat treatment scheduling

    OpenAIRE

    Al-Kanhal, Tawfeeq

    2010-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. This research is focused on the integration problem of process planning and scheduling in steel heat treatment operations environment using artificial intelligent techniques that are capable of dealing with such problems. This work addresses the issues involved in developing a suitable methodology for scheduling heat treatment operations of steel. Several intelligent algorithms have been...

  20. Refrigerant Control Strategies for Residential Air-Conditioning and Heat-Pump System

    Institute of Scientific and Technical Information of China (English)

    SU Shun-yu; ZHANG Chun-zhi; CHEN Jian

    2009-01-01

    This paper simulated the optimal refrigerant charge inventory of a refrigeration system in air-con-ditioning operation and heat-pump operation respectively,and studied the refrigerant control strategies in this system.The void fraction in two-phase fluid region was calculated by Harms model.And based on distributed parameter model and Harms model,the refrigerant charge inventory in condenser and evaporator were calculated and analyzed in air-conditioning conditions and heat-pump conditions,respectively.The calculating results of dif-ferent refrigerant mass between refrigeration and heating conditions indicate that the optimal refrigerant charge inventory in heat-pump conditions is lower than that in air-eonditioning conditions.To avoid the decrease of COP due to the surplus refrigerant in heating conditions,we introduced the liquid reservoir control method and associate capillary control method.Both of them could increase the heating capacity of the air-source heat pump-The difference of optimal refrigerant charge inventory in air-conditioning and heat-pump system can be controlled by the liquid reservoir or the associate capillary.

  1. A Literature Review on Heating of Ventilation Air with Large Diameter Earth Tubes in Cold Climates

    Directory of Open Access Journals (Sweden)

    Lili Tan

    2013-07-01

    Full Text Available Earth-air heat exchange (EAHE systems offer the possibility of reducing use of nonrenewable energy for heating ventilation air in cold climates. The number of installations of large diameter (greater than 900 mm EAHE systems reported for cold climates is small. Even less has been reported on their heating performance, but the available information suggests that further rigorous assessment is warranted to determine whether the reported better than expected temperature rise is supported and, if so, the reasons for this. Another concern is the possibility of long-term heat depletion in the surrounding soil, which would affect performance. Only a couple of short-term experimental studies of ground temperature effects of heating with EAHE were found for cool climates. Four articles that addressed ground temperature effects with horizontal ground source heat pump exchangers had conflicting findings regarding heat depletion in the soil.

  2. Power Efficiency of Systems Applied for Heating Building and Structure External Walls with Ventilated Air Spaces

    OpenAIRE

    I. F. Fialko; A. S. Statsenko

    2014-01-01

    The paper considers power-efficient systems applied for heating building and structure external walls with ventilated air spaces and prescribes directions and problems pertaining to power-efficiency improvement of such systems.

  3. Improved Modeling of Residential Air Conditioners and Heat Pumps for Energy Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, D.; Winkler, J.; Kruis, N.; Christensen, C.; Brendemuehl, M.

    2013-01-01

    This report presents improved air conditioner and heat pump modeling methods in the context of whole-building simulation tools, with the goal of enabling more accurate evaluation of cost effective equipment upgrade opportunities and efficiency improvements in residential buildings.

  4. Simultaneous heat and mass transfer to air from a compact heat exchanger with water spray precooling and surface deluge cooling

    International Nuclear Information System (INIS)

    Various methods are available to enhance heat exchanger performance with evaporative cooling. In this study, evaporative mist precooling, deluge cooling, and combined cooling schemes are examined experimentally and compared to model predictions. A flexible model of a compact, finned-tube heat exchanger with a wetted surface is developed by applying the governing conservation and rate equations and invoking the heat and mass transfer analogy. The model is applicable for dry, partially wet, or fully wet surface conditions and capable of predicting local heat/mass transfer, wetness condition, and pressure drop of the heat exchanger. Experimental data are obtained from wind tunnel experiments using a louver-fin flat-tube heat exchanger with single-phase tube-side flow. Total capacity, pressure drop, and water drainage behavior under various water usage rates and air face velocities are analyzed and compared to data for dry-surface conditions. A heat exchanger partitioning method for evaporative cooling is introduced to study partially wet surface conditions, as part of a consistent and general method for interpreting wet-surface performance data. The heat exchanger is partitioned into dry and wet portions by introducing a wet surface factor. For the wet part, the enthalpy potential method is used to determine the air-side sensible heat transfer coefficient. Thermal and hydraulic performance is compared to empirical correlations. Total capacity predictions from the model agree with the experimental results with an average deviation of 12.6%. The model is also exercised for four water augmentation schemes; results support operating under a combined mist precooling and deluge cooling scheme. -- Highlights: • A new spray-cooled heat exchanger model is presented and is validated with data. • Heat duty is shown to be asymptotic with spray flow rate. • Meaningful heat transfer coefficients for partially wet conditions are obtained. • Colburn jwet is lower than jdry

  5. Thermal Sizing of Heat Exchanger Tubes for Air Natural Convective Cooling System of Emergency Cooling Tank

    International Nuclear Information System (INIS)

    For the long operation of secondary passive cooling system, however, water level goes down by evaporation in succession at emergency cooling tank. At the end there would be no place to dissipate heat from condensation heat exchanger. Therefore, steam cooling heat exchanger is put on the top of emergency cooling tank to maintain appropriate water level by collecting evaporating steam. Steam cooling heat exchanger is installed inside an air chimney and evaporated steam is cooled down by air natural convection. In this study, thermal sizing of steam cooling heat exchanger under air natural convection was conducted by TSCON program for the design of experimental setup as shown in Fig. 2. Thermal sizing of steam cooling heat exchanger tube under air natural convection was conducted by TSCON program for the design of experimental setup. 25 - 1' tubes which has a length 1687 mm was determined as steam cooling heat exchanger at 2 kW heat load and 100 liter water pool in emergency cooling tank (experimental limit condition). The corresponding width of two tubes is 50 mm and has 5 by 5 tube array for heat exchanger

  6. Rapid methods for assessing efficiency of heat treatment of milk

    OpenAIRE

    Sharma, Rajan; Rajput, Y. S.

    2012-01-01

    Two methods based on the activity of γ-glutamyl transpeptidase and lactoperoxidase are developed for assessing the efficiency of heat treatment of milk at 80 °C for 15 s. Heat treatment of milk at 80 °C (15 s) completely inactivates both milk enzymes. Under the selected assay conditions, enzyme activities are related with intensity of pink colour of product. In contrast to raw (unheated) milk which gives pink colour under the test conditions, heated milk (80 °C, 15 s) remains either white or ...

  7. Optical fiber temperature sensors: applications in heat treatments for foods

    Science.gov (United States)

    Sosa-Morales, María Elena; Rojas-Laguna, Roberto; López-Malo, Aurelio

    2010-10-01

    Heat treatments are important methods to provide safe foods. Conventional heat treatments involve the application of steam and recently microwave treatments have been studied and applied as they are considered as fast, clean and efficient. Optical fiber sensing is an excellent tool to measure the temperature during microwave treatments. This paper shows the application of optical fiber temperature sensing during the heat treatment of different foods such as vegetables (jalapeño pepper and cilantro), cheese and ostrich meat. Reaching the target temperature, important bacteria were inactivated: Salmonella, Listeria and Escherichia coli. Thus, the use of optical fiber sensors has resulted be a useful way to develop protocols to inactivate microorganisms and to propose new methods for food processing.

  8. Device with Complex System for Heat Utilization and Reduction of Hazardous Air Emissions

    Directory of Open Access Journals (Sweden)

    O. Kascheeva

    2012-01-01

    Full Text Available Investigations concern heat utilization and reduction of hazardous emissions occurring in residential buildings and accompanying operation of a great number of industrial enterprises in particular heat and power objects, and firstly, heat-generating units of small power located in densely populated residential areas without centralized heat supply.The investigation target is to reduce cost of heat produced by independent system of building heat supply, reduction of air pollution  due to hazardous gas emissions and reduction of heat pollution of the environment as a result of building ventilation system operation, ventilation of their internal and external sewerage network and higher reliability of their operation.The target is achieved because the device with complex system for heat utilization and reduction of hazardous air emissions has additionally an assembly tank for mixing flue gases, ventilation emissions and atmospheric air, heat pump. Evaporation zone of the pump is a condensator of the gas mixture and its condensate zone contains a heat supply line for a heat consumer. The line is equipped with assembling  and distributing collectors, pipeline connecting the heat supply line with the system of direct and return delivery water from a boiler house, a separator for division of liquid and gaseous mixture phases, neutralizing devices for separate reduction of concentrations of hazardous and odorous substances being released in gaseous and liquid portions of the mixture, a pipeline for periodic supply of air with higher concentration of hazardous and odorous substances in the boiler furnace. The supplied air is obtained as a result of its passing through gas filters at their regeneration when their exchange capacity is exhausted.

  9. Experimental Investigation and Optimization of Air-Water SprayImpingement Cooling to Enhance Heat Transfer

    Directory of Open Access Journals (Sweden)

    Santosh Kumar Nayak

    2016-02-01

    Full Text Available The current research focused with the optimization of the heat flux from the surface of a hot steel test plate by air atomized water spray cooling. The air atomized water spray cooling experimental setup was designed and fabricated at School of Mechanical Engineering KIIT University, Odisha, India to investigate the role of various process parameters to enhance the heat flux from the surface of the heated steal specimen. The dimensions of test specimen used in the experiment were 120 mm X 120 mm, having different thickness of 4 mm, 6 mm and 8 mm. The effect of the process parameters such as thickness of the test plate, nozzle to plate distance, air and water pressure for removal of heat flux were optimized. The optimization of the controlling parameters was carried out by using the response surface method (RSM. A new correlation was developed for optimization of the surface heat flux.

  10. A novel defrosting method using heat energy dissipated by the compressor of an air source heat pump

    International Nuclear Information System (INIS)

    Highlights: • A novel defrosting method using heat energy dissipated by the compressor was developed and examined. • During the defrosting process, mean temperature difference between the air entering and leaving the indoor coil reached 4.1 °C. • Compared to the traditional method, defrosting time was shortened by 65% while the resuming heating period disappeared. • For the defrosting operation, the total energy consumption was less than 27.9% compared to the traditional method. - Abstract: When an air source heat pump (ASHP) unit is used for space heating at low ambient temperatures in winter, frost may form on its outdoor coil surface. Since the accumulated frost adversely affects its performance and energy efficiency, periodic defrosting of the outdoor coil is necessary. Currently, the reverse-cycle defrosting (RCD) method is widely used for the defrosting of ASHP. However, this operation interrupts space heating during the defrosting process. A time lag occurs to resume heating at end of the defrosting cycle. Moreover, frequent reversing of the 4-way valve may cause mass leakage of the refrigerant, even make the system unsafe. Furthermore, some amount of heat is dissipated to the atmosphere through the compressor casing. To improve the defrosting process and use this waste heat, a novel ASHP unit is developed. The space is heated during the defrosting process using the heat dissipated by the compressor. Experiments using both the RCD method and the novel reverse cycle defrosting (NRCD) method developed in this study are conducted on an ASHP unit of 8.9 kW nominal heating capacity. The experimental results indicated that in the NRCD method, the discharge and suction pressures are increased by 0.33 MPa and 0.14 MPa, respectively, the defrosting time is shortened by 65% while the resuming heating period vanished with the NRCD method, and that the total energy consumption in comparison to RCD method is reduced by 27.9% during the period which is composed

  11. Radiation Heat Transfer Effect on Thermal Sizing of Air-Cooling Heat Exchanger of Emergency Cooldown Tank

    International Nuclear Information System (INIS)

    An attempt has begun to extend the life time of emergency cooldown tank (ECT) by Korea Atomic Energy Research Institute (KAERI) researchers. Moon et al. recently reported a basic concept upon how to keep the ECT in operation beyond 72 hours after an accident occurs without any active corrective actions for the postulated design basis accidents. When the SMART (System-integrated Modular Advanced Reac-Tor) received its Standard Design Approval (SDA) for the first time in the world, hybrid safety systems are applied. However, the passive safety systems of SMART are being enforced in response to the public concern for much safer reactors since the Fukushima accident occurred. The ECT is a major component of a passive residual heat removal system (PRHRS), which is one of the most important systems to enhance the safety of SMART. It is being developed in a SMART safety enhancement project to contain enough cooling water to remove a sensible heat and a decay heat from reactor core for 72 hours since an accident occurs. Moon et al. offered to install another heat exchanger above the ECT and to recirculate an evaporated steam into water, which enables the ECT to be in operation, theoretically, indefinitely. An investigation was made to determine how long and how many tubes were required to meet the purpose of the study. In their calculation, however, a radiation heat transfer effect was neglected. The present study is to consider the radiation heat transfer for the design of air-cooling heat exchanger. Radiation heat transfer is normally ignored in many situations, but this is not the case for the present study. Kim et al. conducted thermal sizing of scaled-down ECT heat exchanger, which will be used to validate experimentally the basic concept of the present study. Their calculation is also examined to see if a radiation heat transfer effect was taken into consideration. The thermal sizing of an air-cooling heat exchanger was conducted including radiation heat transfer

  12. An Energy Savings Model for the Heat Treatment of Castings

    Energy Technology Data Exchange (ETDEWEB)

    Y. Rong; R. Sisson; J. Morral; H. Brody

    2006-12-31

    An integrated system of software, databases, and design rules have been developed, verified, and to be marketed to enable quantitative prediction and optimization of the heat treatment of aluminum castings to increase quality, increase productivity, reduce heat treatment cycle times and reduce energy consumption. The software predicts the thermal cycle in critical locations of individual components in a furnace, the evolution of microstructure, and the attainment of properties in heat treatable aluminum alloy castings. The model takes into account the prior casting process and the specific composition of the component. The heat treatment simulation modules can be used in conjunction with software packages for simulation of the casting process. The system is built upon a quantitative understanding of the kinetics of microstructure evolution in complex multicomponent alloys, on a quantitative understanding of the interdependence of microstructure and properties, on validated kinetic and thermodynamic databases, and validated quantitative models.

  13. Dynamic Models of Heating and Cooling Coils with One—Dimensional Air Distribution

    Institute of Scientific and Technical Information of China (English)

    WangZijie; G.Krauss

    1993-01-01

    This paper presents the simulation models of the plate-fin,air-to-water(or water vapour) heat exchangers used as air-heating or air-cooling and dehumidifying colis in the HVAC(Heating,Ventilation and AIr-Conditioning)systems.The thermal models are used to calculate the heat exchange between distributing air and coil pipes and outlet temperatures of air and heat or chilled fluid.The aerodynamic models are used to account for the pressure drop of the air crossing the coil tubes,They can also be used to optimize the structres of such coils.The models are based on principal laws of teat and mass conservation and fluid mechanics.They are transparent and easy to use.In our work,a coil is considered as an assembly of numbers of basic elements in which all the state variables are unique.Therefore we can conveniently simulate the coils with different structures and different geometric parameters.Two modular programs TRNSYS(Transient System Simulation)and ESACAP are utilized as supporting softwares which make the programming and simulation greatly simplified.The coil elements and a real coil were simulated.The results were compared with the data offered by the manufacturer(company SOFICA) and also with those obtained using critical methods such as NTU method ,etc.and good agreement is attained.

  14. Effect of heat treatment on fatigue crack growth rate of inconel 690

    International Nuclear Information System (INIS)

    The effects of heat treatment on fatigue crack growth rates (FCGRs) of Inconel 690 have been investigated in terms of carbide morphology and grain size. Cycling tests in air at room temperature have shown that FCGR in low stress intensity factor range (ΔK) region can be effectively reduced by increasing the grain boundary carbide precipitate size and grain size. Decrease in FCGR is attributed to the crack tip blunting at the precipitates of grain boundary chromium carbides

  15. Ultrasonic Inspection following Heat Treatment of Uranium Alloys

    International Nuclear Information System (INIS)

    To improve the behaviour of low uranium alloys in reactors it is often necessary to reduce grain size by heat treatment. It has proved essential to provide for inspection of the whole element and the entire output in order to discover the exact quality of the fuel used. This inspection cannot be made by micrography because of the time required and the fact that the data obtained are incomplete. The inspection system adopted is based on the principle of absorption of ultrasonic waves by materials. This absorption depends on the structure of the medium. If λ is small in relation to grain size G, absorption is low; whereas if G is of the order of λ/2, absorption is very high. The tests were made first in air, using the multiple-echo system, then by measuring the height of the first echo, and finally by transmission in water, the height of the transmitted echo being compared with that of the initial signal. In industrial use, the amplitude of the echo transmitted by the material is compared with the echo obtained from a standard of the same characteristics and shape. Inspection takes place in a special machine in which the materials are rotated by rollers and adjustable transducers move over the element. The helicoidal scanning is carried out with a pitch of less than 5 mm. The ultrasonic generator includes a control system ensuring a constant reference echo. The paper quotes a series of records showing the results obtained with various alloys and in particular the faults observed in elements treated by induction upon linear displacement. The arrangement can detect faulty treatment zones of less than 1 cm2. The system is at present used to inspect all low alloy uranium fuels of the G2, EL3, EDF1, EDF2 and INCA reactors, i.e. rods and tubes with diameters between 20 and 95 mm. (author)

  16. Augmentation of forced flow boiling heat transfer by introducing air flow into subcooled water flow

    International Nuclear Information System (INIS)

    The effect of air injection into a subcooled water flow on boiling heat transfer and a critical heat flux (CHF) was examined experimentally. Experiments were conducted in the range of subcooling of 50 K, a superficial velocity of water and air Ul = 0.17 ∼ 3.4 and Ug = 0 ∼ 15 m/s, respectively. A test heat transfer surface was a 5 mm wide, 40 mm long and 0.5 mm thick stainless steel sheet embedded on the bottom wall of a 10 mm high and 20 mm wide rectangular flow channel. Nine times enhancement of the heat transfer coefficient in the non-boiling region was attained at the most by introducing an air flow into a water single-phase flow. The heat transfer improvement was prominent when the water flow rate was low and the air introduction was large. The present results of the non-boiling heat transfer were well correlated with the Lockhart-Martinelli parameter Xtt; hTP/hL0 = 5.0(1/ Xtt)0.5. The air introduction has some effect on the augmentation of heat transfer in the boiling region, however, the two-phase flow effect was little and the boiling was dominant in the fully developed boiling region. The CHF was improved a little by the air introduction in the high water flow region. However, that was rather greatly reduced in the low flow region. Even so, the general trend by the air introduction was that qCHF increased as the air introduction was increased. The heat transfer augmentation in the non-boiling region was attained by less power increase than that in the case that only the water flow rate was increased. From the aspect of the power consumption and the heat transfer enhancement, the small air introduction in the low water flow rate region seemed more profitable, although the air introduction in the high water flow rate region and also the large air introduction were still effective in the augmentation of the heat transfer in the non-boiling region. (author)

  17. Theoretical energy saving analysis of air conditioning system using heat pipe heat exchanger for Indian climatic zones

    OpenAIRE

    T.S. Jadhav; M.M. Lele

    2015-01-01

    Heat pipe heat exchanger (HPHX) is an excellent device used for heat recovery in air conditioning systems. The Energy Conservation Building Code (ECBC) – Bureau of Energy Efficiency (BEE) India classifies Indian climatic zones into five categories viz., Hot and Dry (e.g. Ahmedabad, Jodhpur etc), Warm and Humid (e.g. Mumbai, Chennai etc), Composite (e.g. Nagpur, Jaipur etc), Cold (e.g. Guwahati etc) and Temperate (e.g. Bengaluru etc). The literature review indicated that very limited informati...

  18. The conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK

    Directory of Open Access Journals (Sweden)

    V.M. Yakubson

    2014-04-01

    Full Text Available On April, 11th, in Lenexpo the XVI conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK “Effective HVAC and Heat Supply Systems” took place. There were a lot of presentations of new equipment for building systems and networks. All these reports were dedicated to the ways to make buildings more comfortable for people, to increase the energy efficiency, to reduce expenses and to improve the production efficiency. But besides the specific equipment, there were some reports dedicated to more general problems in design, installation and maintenance of building systems and networks

  19. Heat pump air conditioning system for pure electric vehicle at ultra-low temperature

    Directory of Open Access Journals (Sweden)

    Li Hai-Jun

    2014-01-01

    Full Text Available When the ordinary heat pump air conditioning system of a pure electric vehicle runs at ultra-low temperature, the discharge temperature of compressor will be too high and the heating capacity of the system will decay seriously, it will lead to inactivity of the heating system. In order to solve this problem, a modification is put forward, and an experiment is also designed. The experimental results show that in the same conditions, this new heating system increases more than 20% of the heating capacity; when the outside environment temperature is negative 20 degrees, the discharge temperature of compressor is below 60 degrees.

  20. Performance Evaluation of Air-Based Heat Rejection Systems

    OpenAIRE

    Hannes Fugmann; Björn Nienborg; Gregor Trommler; Antoine Dalibard; Lena Schnabel

    2015-01-01

    On the basis of the Number of Transfer Units (NTU) method a functional relation between electric power for fans/pumps and effectiveness in dry coolers and wet cooling towers is developed. Based on this relation, a graphical presentation method of monitoring and simulation data of heat rejection units is introduced. The functional relation allows evaluating the thermodynamic performance of differently sized heat rejection units and comparing performance among them. The method is used to evalua...

  1. High-speed heating saves energy in heat treatment processes; Energieeinsparung durch Schnellerwaermung in der Waermebehandlung

    Energy Technology Data Exchange (ETDEWEB)

    Saemann, Patrick Michael; Schroeder, Dominikus; Hanus, Adolf [LOI Thermprocess GmbH, Essen (Germany); Dragulin, Dan [BELTE AG, Delbrueck (Germany)

    2012-02-15

    Unceasing increases in energy-prices, combined with the ever greater urgency of reducing environmental burdens, are significant inducements to industrial-furnace engineers, in particular, to develop new, more energyefficient processes. Nearly 40 % of industrially used energy in Germany are consumed by industrial furnaces [1]. LOI Thermprocess assists in conserving the environment by reducing energy consumption, using its new, innovative heat treatment processes. Joint tests on high-speed heating in heat treatment of aluminium cylinder heads have been conducted with Belte AG, and are reported here. (orig.)

  2. Modeling of an Air Conditioning System with Geothermal Heat Pump for a Residential Building

    Directory of Open Access Journals (Sweden)

    Silvia Cocchi

    2013-01-01

    Full Text Available The need to address climate change caused by greenhouse gas emissions attaches great importance to research aimed at using renewable energy. Geothermal energy is an interesting alternative concerning the production of energy for air conditioning of buildings (heating and cooling, through the use of geothermal heat pumps. In this work a model has been developed in order to simulate an air conditioning system with geothermal heat pump. A ground source heat pump (GSHP uses the shallow ground as a source of heat, thus taking advantage of its seasonally moderate temperatures. GSHP must be coupled with geothermal exchangers. The model leads to design optimization of geothermal heat exchangers and to verify the operation of the geothermal plant.

  3. WEXA: exergy analysis for increasing the efficiency of air/water heat pumps - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gasser, L.; Wellig, B.; Hilfiker, K.

    2008-04-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) presents the results of a study at the made by the Engineering and Architecture department at the Lucerne University of Applied Sciences and Arts. The subject of the WEXA study (Waermepumpen-Exergie-Analyse - heat pump exergy analysis) is the analysis of the operation of air/water heat-pumps using exergy analysis methods. The basic thermodynamics of heating systems using heat-pumps is discussed. The exergy analyses and exergy balances for the various components and processes of an air/water heat-pump are presented and discussed. Comparisons are presented for heat-pumps with on/off and continuous control systems for their compressors and fans. The paper is concluded with a collection of appendices on the subject.

  4. Coffee husk associated with firewood as fuel for indirect heating of drying air

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Edney Alves; Silva, Juarez de Sousa e; Silva, Jadir Nogueira da; Oliveira Filho, Delly [Universidade Federal de Vicosa (DEA/UFV), MG (Brazil). Dept. de Engenharia Agricola; Donzeles, Sergio Mauricio Lopes [Empresa de Pesquisa Agropecuaria de Minas Gerais (EPAMIG), Vicosa, MG (Brazil)

    2008-07-01

    The objective of this work was the performance analysis of a furnace, burning coffee husk associated with firewood to heat the drying air passing through a heat exchanger. For the analysis the temperature variation, the combustion quality, the heat losses and the furnace thermal efficiency were all monitored. Results showed that the furnace average efficiency was 58.3% and the heat losses in the exhaust were 24.3%. The presence of carbon monoxide in the exhaust gases (average 2982.8 ppm) had proven incomplete combustion, and suggesting that the combustion gases can not be used to directly drying of foods. Despite of indirect heating, the presented thermal efficiency indicates that the burning of coffee husks is one economic alternative for air heating in grain drying or in other agricultural processes. (author)

  5. Transient Performance of Air-cooled Condensing Heat Exchanger in Long-term Passive Cooling System during Decay Heat Load

    International Nuclear Information System (INIS)

    In the event of a 'loss of coolant accident'(LOCA) and a non-LOCA, the secondary passive cooling system would be activated to cool the steam in a condensing heat exchanger that is immersed in an emergency cooldown tank (ECT). Currently, the capacities of these ECTs are designed to be sufficient to remove the sensible and residual heat from the reactor coolant system for 72 hours after the occurrence of an accident. After the operation of a conventional passive cooling system for an extended period, however, the water level falls as a result of the evaporation from the ECT, as steam is emitted from the open top of the tank. Therefore, the tank should be refilled regularly from an auxiliary water supply system when the system is used for more than 72 hours. Otherwise, the system would fail to dissipate heat from the condensing heat exchanger due to the loss of the cooling water. Ultimately, the functionality of the passive cooling system would be seriously compromised. As a passive means of overcoming the water depletion in the tank, Kim et al. applied for a Korean patent covering the concept of a long-term passive cooling system for an ECT even after 72 hours. This study presents transient performance of ECT with installing air-cooled condensing heat exchanger under decay heat load. The cooling capacity of an air-cooled condensing heat exchanger was evaluated to determine its practicality

  6. Integration of Heat Treatment in precision forging of gear wheels

    International Nuclear Information System (INIS)

    The conventional process chain for the production of gear wheels demands many manufacturing steps. Typically this process chain consists of cutting, heating, forging and deburring. Subsequently, the teeth and the bores of the gears are shaped in a machining process such as milling, slotting and broaching. Afterwards, a heat treatment by case hardening is applied and the gears are finally finished by grinding by grinding. This process chain is often disrupted by storage and transports. Precision forging can significantly reduce this process chain because deburring and machining steps become unnecessary. Additional advantages can be gained if the heat of the precision forging process is used for an integrated heat treatment. Moreover, specific component characteristics can be reached by integrating the heat treatment in connection with an adapted process technology. Hot formed parts are directly hardened by using the forging heat. A new solution for a homogeneous cooling consisting of a two-phase nozzle array will be introduced. The application of this technique allows the hardening of particular component regions according to typical strain profiles of this component. Besides, demands on material properties, an even allowance after the precision forging process has to be maintained. The allowance after the forging process depends on varying alloys and the geometry of the part as well as the forging temperature and related heat loss. The tool must therefore be corrected and adapted accordingly. The new approach for the presented process chain with new tool concepts and an integrated heat treatment using the forging heat will solve many problems. Moreover, dramatic change in the process management is necessary. But on the other hand it offers great potential for cost reduction. Particularly, high-duty automotive components offer a wide application field for the precision forging technology. Advantages like shortened production cycles achieved by eliminating machining

  7. Analysis of air-to-water heat pump in cold climate: comparison between experiment and simulation

    OpenAIRE

    Karolis Januševičius; Giedrė Streckienė

    2015-01-01

    Heat pump systems are promising technologies for current and future buildings and this research presents the performance of air source heat pump (ASHP) system. The system was monitored, analysed and simulated using TRNSYS software. The experimental data were used to calibrate the simulation model of ASHP. The specific climate conditions are evaluated in the model. It was noticed for the heating mode that the coefficient of performance (COP) varied from 1.98 to 3.05 as the outdoor temperature ...

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

    International Nuclear Information System (INIS)

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

  9. Influence of Different Vortex Generators on Heat Transfer in Direct Air-Cooled Condensers

    Institute of Scientific and Technical Information of China (English)

    ZHOU Guobing; YANG Laishun

    2012-01-01

    With the capacity of air cooling turbines increasing, the air-cooled steam condenser has been developed to the single fiat tube. Fig.1 shows the studied single-row wavy-finned flat tube. Vortex generators are more and more used in oil and chemical industry, power generation, and refrigeration industry in the heat exchanger. The analyses are performed to investigate the effect of vortex generators on pressure drop and heat transfer of single-row wavy-finned fiat tubes of direct air-cooled condensers.

  10. Process Integrated Heat Treatment of a Microalloyed Medium Carbon Steel: Microstructure and Mechanical Properties

    Science.gov (United States)

    Herbst, Sebastian; Schledorn, Mareike; Maier, Hans Jürgen; Milenin, Andrij; Nürnberger, Florian

    2016-04-01

    Air-water spray cooling was employed during a heat treatment to enhance the mechanical properties of microalloyed medium carbon steel test cylinders (38MnVS6, 88 mm diameter). Using appropriate cooling times and intensities, the test cylinders' surfaces could be quenched and subsequently self-tempered by the residual heat of the core. Simultaneously, it was possible to keep the core regions of the cylinders in the bainitic regime and carry out a quasi-isothermal holding. The resulting microstructures consisted of tempered martensite (near-surface) and bainite with pearlite and ferrite (core). Compared to the standard heat treatment (controlled air cooling), the tensile properties (proof stress and ultimate tensile strength) could be improved for both near-surface and core regions with the adapted spray cooling. A hardness profile with 450 HV10 surface hardness and a hardening depth of more than 11 mm could be realized. In addition, an increase of the impact toughness for the core was achieved, resulting in approximately 25 J charpy impact energy. This is a substantial improvement compared to standard heat treatment procedure and values reported in the literature and can be attributed to the reduced pearlite volume fraction and the increased amount of fine bainite.

  11. Effect of heat treatment on stainless steel orthodontic wires.

    Science.gov (United States)

    Cuoghi, Osmar Aparecido; Kasbergen, Geraldo Francisco; Santos, Paulo Henrique dos; Mendonça, Marcos Rogério de; Tondelli, Pedro Marcelo

    2011-01-01

    This study evaluated the effect of heat treatment on CrNi stainless steel orthodontic archwires. Half of forty archwires of each thickness - 0.014" (0.35 mm), 0.016" (0.40 mm), 0.018" (0.45 mm) and 0.020" (0.50 mm) (totalling 160 archwires) - were subjected to heat treatment while the remainder were not. All of the archwires had their individual thickness measured in the anterior and posterior regions using AutoCad 2000 software before and after compressive and tensile strength testing. The data was statistically analysed utilising multivariance ANOVA at a 5% significance level. All archwires without heat treatment that were subjected to tensile strength testing presented with anterior opening, which was more accentuated in the 0.020" archwires. In the posterior region, the opening produced by the tensile force was more accentuated in the archwires without heat treatment. There was greater stability in the thermally treated archwires, especially those subjected to tensile strength testing, which indicates that the heat treatment of orthodontic archwires establishes a favourable and indispensable condition to preserve the intercanine width. PMID:21359492

  12. Performance Evaluation of Air-Based Heat Rejection Systems

    Directory of Open Access Journals (Sweden)

    Hannes Fugmann

    2015-01-01

    Full Text Available On the basis of the Number of Transfer Units (NTU method a functional relation between electric power for fans/pumps and effectiveness in dry coolers and wet cooling towers is developed. Based on this relation, a graphical presentation method of monitoring and simulation data of heat rejection units is introduced. The functional relation allows evaluating the thermodynamic performance of differently sized heat rejection units and comparing performance among them. The method is used to evaluate monitoring data of dry coolers of different solar cooling field projects. The novelty of this approach is that performance rating is not limited by a design point or standardized operating conditions of the heat exchanger, but is realizable under flexible conditions.

  13. Investigation of the Indoor Environment in a Passive House Apartment Building Heated by Ventilation Air

    DEFF Research Database (Denmark)

    Lysholt Hansen, MathiasYoung Bok; Koulani, Chrysanthi Sofia; Peuhkuri, Ruut Hannele;

    2014-01-01

    Experience has shown that appropriate design of very low energy dwellings can be a large challenge and that the final design may result in insufficient heating in winter and overheating in summer. The 126 certified Passive House apartments (Ravnsborghusene) in Køge, Denmark are a low energy...... building project finished medio 2012. The design challenge was met with a concept of air heating that is individually controlled in every room. It also applies external solar shading. This study used indoor climate measurements and dynamic simulations in one of these apartment buildings to evaluate thermal...... comfort and the performance of the air heating system and solar shading. Thermal comfort category B according to ISO 7730 was obtained in the building during field measurements, indicating that the air heating system was able to maintain comfort conditions in winter, when the outdoor temperature had been...

  14. Solutions for Energy Efficient and Sustainable Heating of Ventilation Air: A Review

    Directory of Open Access Journals (Sweden)

    A. Žandeckis

    2015-10-01

    Full Text Available A high energy efficiency and sustainability standards defined by modern society and legislation requires solutions in the form of complex integrated systems. The scope of this work is to provide a review on technologies and methods for the heating of ventilation air as a key aspect for high energy and environmental performance of buildings located in a cold climate. The results of this work are more relevant in the buildings where space heating consumes a significant part of the energy balance of a building, and air exchange is arranged in an organized manner. A proper design and control strategy, heat recovery, the use of renewable energy sources, and waste heat are the main aspects which must be considered for efficient and sustainable ventilation. This work focuses on these aspects. Air conditioning is not in the scope of this study.

  15. Heat exchanger design for hot air ericsson-brayton piston engine

    Directory of Open Access Journals (Sweden)

    Ďurčanský P.

    2014-03-01

    Full Text Available One of the solutions without negative consequences for the increasing energy consumption in the world may be use of alternative energy sources in micro-cogeneration. Currently it is looking for different solutions and there are many possible ways. Cogeneration is known for long time and is widely used. But the installations are often large and the installed output is more suitable for cities or industry companies. When we will speak about decentralization, the small machines have to be used. The article deals with the principle of hot-air engines, their use in combined heat and electricity production from biomass and with heat exchangers as primary energy transforming element. In the article is hot air engine presented as a heat engine that allows the conversion of heat into mechanical energy while heat supply can be external. In the contribution are compared cycles of hot-air engine. Then are compared suitable heat exchangers for use with hot air Ericsson-Brayton engine. In the final part is proposal of heat exchanger for use in closed Ericsson-Brayton cycle.

  16. Analysis and Modeling of Curing Polyester Resin in Cylindrical Moulds Heated by Air

    Directory of Open Access Journals (Sweden)

    Gomzi, Z.

    2009-09-01

    Full Text Available The mathematical model of the cure of unsaturated polyester resin in cylindrical mould heated with warm air was suggested and derived. The model assumes convective heat transfer through air on the wall of the mould and conductive heat transfer through the resin. The temperature within the sample changes during the cure process, which is the result of the reaction being exothermal and the process of heat transfer. The addition of the filler changes the thermal properties of the mixture and reduces the amount of heat generated during the reaction in the sample of the same volume, which leads to lower temperature maximums in the center of the cylindrical mould. The model was tested with multiple experiments in which the temperature of the resin inside the mould during the cure process was measured. The heat transfer coefficients between the air and wall of the mould with different speeds of air flow were estimated using independent experiments where the glycerol was used instead of resin. Estimated values were compared with known correlations and good agreement was obtained. Using the suggested model, the cure process in the cylindrical mould can be simulated accurately and influents of the heat transfer and reaction rate on the temperature maximums can be studied.

  17. Reducing the energy consumption of an earth–air heat exchanger with a PID control system

    International Nuclear Information System (INIS)

    Highlights: • The application of control actions to green technologies has been simulated. • Energy consumption of green technologies can be reduced even more. • The efficiency of green technologies can be raised. • Environmental concerns can be diminished. • The sustainability of the planet can be increased. - Abstract: Reducing environmental emissions is one of the challenges that human being has to overcome. It can only be reached with a proper energetic efficiency and management of the processes that exist in the society nowadays. Several academic works have mentioned that raising the efficiency of a process it also increases sustainability and in turn decreases the environmental impact. One process that requires much attention is the cooling and heating of buildings; this process contributes to the major part of the electric bill, in particular, if a conventional and old air conditioning is used as commonly occurs in many countries. In recent years there have been developed new alternatives that are used in few countries, such as the earth–air heat exchanger, where air is passed through a heat exchanger buried a few meters below the ground. The heat exchanger takes advantage of the well-known difference between the temperature of the surrounding air and the temperature of the ground for cooling or heating the air that is subsequently injected into the buildings. This process requires less energy, then in the present work is thought that a PID (Proportional, Integral and Derivative) controller can be applied to an earth–air heat exchanger to reduce even more the energy consumption. Therefore, a simulation of a thermodynamic model of an earth–air heat exchanger was done and used along with a PID controller, to estimate savings in energy consumption. The results show that the energy consumption can be reduced up to 87% with the PID control, hence the efficiency of the process is increased as well as the sustainability of the planet and thus the

  18. EFFECTS OF COMPRESSED AIR FOAM APPLICATION ON HEAT

    Directory of Open Access Journals (Sweden)

    Adam THOMITZEK

    2015-12-01

    Full Text Available This article evaluates the knowledge obtained in firefighting tests using compressed air foam system (CAFS within a confined space. Six experiments were conducted for verification during the cooling of rooms and the self-extinguishing effect. The simulation was for a fully developed fire within a room. The fuel was chosen to simulate ordinary combustible materials utilized in residential areas. Mantel thermocouples were placed in the rooms to record the temperature changes. Compressed air foam was first applied with a standard fire hose nozzle to the ceiling and then to the epicenter of fire. Fire extinguishing was initiated after reaching the desired temperature in the room. The temperature for the start of fire extinguishing matched the third phase of development of a fire. Fire extinguishing was terminated after no obvious signs of fire were shown in epicenter of fire. The outputs of the experiments were evaluated on the basis of the amount of time passed for the temperature to drop below the suggested limit. Individual experiments were also conducted with various different admixing foaming agents over different locations. In the experiments, it has been verified that the application of compressed air foam has a positive effect on room cooling. Use of a compressed air foaming agent does not allow for the development of steam that can scald firefighters and reduce visibility. Furthermore, the extinguishing agent used is more efficient utilizing less water flow out of the fire area.

  19. Development of inherently safe technologies for large scale BWRs. Technologies of heat transfer enhancement of air cooling system

    International Nuclear Information System (INIS)

    After the Fukushima accident, inherently safe technologies for large scale BWRs had been developed and consisted of passive water cooling system, infinite time air cooling system, prevention of hydrogen explosion prevention using SiC fuel claddings and operation support system for plant accidents. This article described development of air cooling system, which consisted of air cooled heat exchanger installed in the outer circumferential part of containment and heat transport system transporting decay heat produced steam to air cooled heat exchanger. Cover was attached outside peripheral part of air cooled heat exchanger, and air flow was generated by stack effect (buoyancy) and cooled heat exchanger targeted as much as 10MW heat removal. Compacting of heat exchanger was essential requisite and technologies of air cooling heat transfer enhancement had been developed. Combination of turbulence promotion ribs and micro fabrication surface, and heat transfer fins were tested and 36% and 65% respective increase in heat transfer were confirmed compared to bare tube, which showed heat transfer performance of air cooled heat exchanger could be enhanced by 100%. (T. Tanaka)

  20. Heat transfer intensification within tube recuperator by inserting secondary emitters inside air channels

    International Nuclear Information System (INIS)

    The research program was stipulated by reduction the service life of the tube recuperators of reheating furnaces at DUNAFERR metallurgical works in Dunaujvaros (Hungary) while replacement the natural gas by coke - oven gas as a furnace fuel took place and air preheating temperature was increased. The tests procedure consists in comparison of temperature and pressure distributions by air flows preheating under air moving inside the tube loops. Advantages of new recuperator design compared to ordinary one have been proven by validation of concept for adequacy to the testing results. The first tests have demonstrated enhancement of local specific and total heat fluxes transferred from flue gases to air flow within the MD tube loops in comparison with those for BD loops by 25 to 45% - dependence on temperature level within the heating (furnace) chamber and on preheated air flow rate. (author)

  1. Cooling, freezing and heating with the air cycle: air as the ultimate green refrigerant

    OpenAIRE

    Verschoor, M.J.E.

    2000-01-01

    Due to the recent concern about the damage that CFCs cause to the environment (ozone layer, global warming) and the absence of commonly acceptable alternative refrigerants, the search for alternative refrigeration concepts is going on. Air as refrigerant in the Joule-Brayton cycle (air cycle) is one of the most natural refrigerants, and it meets all criteria for a refrigerant being environmentally benign. For this reason the air cycle is one of the most promising long-term alternatives for re...

  2. Energetic optimal heating and cooling curves (for air supply)

    NARCIS (Netherlands)

    Plokker, W.; Elkhuizen, P.A.; Peitsman, H.C.

    2003-01-01

    energy efficient legislation and well equipped with insulation, condensing boilers, heat recovery systems, etc. Despite this, many buildings don’t perform as energy efficiently as expected. Also comfort problems occur in large numbers. The problem seems to be the frequently used conventional control

  3. Effect of heat treatment temperature on nitinol wire

    International Nuclear Information System (INIS)

    In-situ synchrotron X-ray diffraction has been used to study the influence of the heat treatment temperature on the subsequent micromechanical behavior of nitinol wire. It was found that increase in the heat treatment temperature rotated the austenite texture from the (332)B2 fiber towards the (111)B2 fiber, and the texture of the Stress-Induced Martensite phase changed from the (1¯40)B19' to the (1¯20)B19' fiber accordingly. Heat treatment at a low temperature reduces the internal residual strains in the austenite during super-elastic deformation and therefore improves the materials fatigue performance. The development of internal residual strains in austenite is controlled by transformation induced plasticity and the reversal martensite to austenite transformation.

  4. Effect of heat treatment temperature on nitinol wire

    Energy Technology Data Exchange (ETDEWEB)

    Cai, S.; Schaffer, J. E. [Fort Wayne Metals Research Products Corporation, 9609 Ardmore Ave., Fort Wayne, Indiana 46809 (United States); Daymond, M. R. [Department of Mechanical and Materials Engineering, Queen' s University, Nicol Hall, 60 Union Street, Kingston, Ontario K7L 3N6 (Canada); Yu, C. [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, 102249 Beijing (China); Ren, Y. [Argonne National Laboratory, 9700 S. Cass Ave, 433/D008, Argonne, Illinois 60439 (United States)

    2014-08-18

    In-situ synchrotron X-ray diffraction has been used to study the influence of the heat treatment temperature on the subsequent micromechanical behavior of nitinol wire. It was found that increase in the heat treatment temperature rotated the austenite texture from the (332){sub B2} fiber towards the (111){sub B2} fiber, and the texture of the Stress-Induced Martensite phase changed from the (1{sup ¯}40){sub B19'} to the (1{sup ¯}20){sub B19'} fiber accordingly. Heat treatment at a low temperature reduces the internal residual strains in the austenite during super-elastic deformation and therefore improves the materials fatigue performance. The development of internal residual strains in austenite is controlled by transformation induced plasticity and the reversal martensite to austenite transformation.

  5. Irradiation in combination of heat treatment of mango puree

    International Nuclear Information System (INIS)

    The effect of irradiation with heat combination treatment on the shelf life and quality of mango puree was studied. Thermal inactivation of polyphenol oxidase enzyme at 80 degree C and 15 min. was used as a measure of adequacy of pre-heat treatment. Irradiation of mango puree after heat treatment at dosage of 0, 2, 4, 6 and 8 kGy showed no change in mc, pH, acidity, and TSS but during storage, growth of microorganisms brought changes in these values. Irradiation in combination with low temperature (5 degree C) reduced discoloration and darkening rate during storage. Irradiation dose from 0 to 8 kGy resulted in log linear reductions in microorganism levels but at 6 and 8 kGy, there was no growth of microorganisms. Products irradiated at 8 kGy showed no microorganism growth at both temperatures

  6. Effect of heat treatment on mechanical properties of H11 tool steel

    Directory of Open Access Journals (Sweden)

    S.Z. Qamar

    2009-08-01

    Full Text Available Purpose: AISI H11 is a special alloy steel, categorized as chromium tool steel. Because of its high toughness and hardness, it is well suited for hot work applications involving very high loads. Typical applications are hot-work forging and extrusion dies, helicopter rotor blades, etc. For longer life and higher design accuracy, properties of this type of tool steel can be improved by various types of heat treatment. Current work reports and analyzes results of mechanical testing performed on variously heat treated H11 steel samples, to arrive at an optimum heat treatment strategy for hot work applications.Design/methodology/approach: Tensile and impact test specimens were fabricated using precision milling and EDM. These samples were subjected to various heat treatment sequences, consisting of annealing, hardening, air and oil quenching, and tempering at different temperatures. Heat treated samples were then mechanically tested for hardness (Rockwell, impact toughness (Charpy, and tensile properties (yield strength, ultimate strength, ductility.Findings: Mechanical testing of H11 samples revealed that with increasing temper temperatures: (a hardness first increases to a maximum and then gradually decreases; (b impact toughness first decreases to a minimum and then increases; (c yield strength first decreases, then increases, and then increases again; (d ultimate strength first increases to a maximum and then steadily decreases; and (e ductility (% elongation gradually decreases till 600ºC, and then increases rather sharply.Practical implications: Though a very promising candidate for hot-work applications, H11 steel is not commonly used for die and tool making. Results of this study can provide die designers and users in the metalworking industry with good guidelines to select proper heat treatment strategies to use H11 steel for various applications.Originality/value: Very little information is available in published literature about

  7. Selection of heat treatment condition of the Mg-Al-Zn alloys

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2009-02-01

    Full Text Available Purpose: Main aim of this paper are results of the optimization of heat treatment conditions, which are temperature and heating time during solution heat treatment or ageing as well the cooling rate after solution treatment for MCMgAl12Zn1, MCMgAl9Zn1, MCMgAl6Zn1, MCMgAl3Zn1 cast magnesium alloys.Design/methodology/approach: The following results concern mechanical properties especially hardness.Findings: The different heat treatment kinds employed contributed to the improvement of mechanical properties of the alloy.Research limitations/implications: According to the alloys characteristic, the applied cooling rate and alloy additions seems to be a good compromise for mechanical properties, nevertheless further tests should be carried out in order to examine different cooling rates and parameters of solution treatment process and aging process.Practical implications: Generally magnesium alloys are applied in motor industry and machine building, but they find application in a helicopter production, planes, disc scanners, a mobile telephony, computers, bicycle elements, household and office equipment, radio engineering and an air - navigation, in chemical, power, textile and nuclear industrial, etc.Originality/value: Contemporary materials should possess high mechanical properties, physical and chemical, as well as technological ones, to ensure long and reliable use. The above mentioned requirements and expectations regarding the contemporary materials are met by the non-ferrous metals alloys used nowadays, including the magnesium alloys.

  8. Simplified Modelling of the Infrared Heating Involving the Air Convection Effect before the Injection Stretch Blowing Moulding of PET Preform

    OpenAIRE

    Luo, Y; Chevalier, Luc; Utheza, Françoise; Nicolas, Xavier

    2014-01-01

    International audience Initial heating conditions and temperature effects (heat transfer with air and mould, self-heating, conduction) have important influence during the ISBM process of PET preforms. The numerical simulation of infrared (IR) heating taking into account the air convection around a PET preform is very time-consuming even for 2D modelling. This work proposes a simplified approach of the coupled heat transfers (conduction, convection and radiation) in the ISBM process based o...

  9. Field Heat Treatment Technician: Competency Profile. Apprenticeship and Industry Training. 20908.1

    Science.gov (United States)

    Alberta Advanced Education and Technology, 2008

    2008-01-01

    The graduate of the Field Heat Treatment Technician apprenticeship program is a certified journeyperson who will be able: (1) use heat treatment equipment to apply heat to materials in order to change a material's properties; (2) Use their knowledge of the properties of heat, industry codes and specifications to determine how heat treatment will…

  10. Optimization of Selecting Air Conditioning Cold/Heat Sources with Grey Relation Analysis

    Institute of Scientific and Technical Information of China (English)

    CAO Guoqing; TU Guangbei

    2006-01-01

    Selection of air conditioning(AC) cold/heat sources generally concerns about certain aspects and cannot reveal the whole profile of the problems.Grey relation analysis (GRA) is a data processing method to categorize the correlation extent of compared sequences and a certain reference sequence in a system with uncertain information.It is applied to evaluating and selecting AC cold/heat sources from four main aspects, which are technology, economy, reliability, and operation and management.Case study shows that the result for selecting AC cold/heat sources with the GRA method can be more reasonable and convincible.Thus it offers a new approach for designers in heating, ventilating and air conditioning field to compare and evaluate different AC cold/heat sources.

  11. Design of a sodium-air heat dissipator capable of transmitting powers till a megawatt

    International Nuclear Information System (INIS)

    This is a theoretical study of the transport phenomenon in which emphasis is put on heat transference. From the chemical and nuclear point of view a revision is made of the sodium behavior as an agent of heat transference and as a fluid. The heat transference is analyzed on wide surfaces and the design of a sodium air heat dissipator capable of transferring powers at the range of a megawatt is presented with a simulation by computer. The results show that the heat transference coefficients don't vary in a great measure in relation with the temperature. This way we can use the caloric temperature for the determination of the sodium properties and the medium temperature for the determination of the air properties. (author)

  12. Satellite estimates of ocean-air heat fluxes during cold air outbreaks

    Science.gov (United States)

    Chou, S.-H.; Atlas, D.

    1982-01-01

    A method for estimating the heat and moisture fluxes of coastal waters using the cloud free path, the sea surface temperature, and the saturation water vapor mixing ratio is presented. Generalized nomograms for the surface sensible and latent heat fluxes are developed using the Stage and Businger (1981) mixed-layer model. The fluxes are found to be slightly dependent on wind speed. The results are found to be applicable to any path within the cloud-free region, with heat fluxes obtainable by multiplication of the mean heating by the mean wind speed in the boundary layer. Higher stability causes lowered heating. It is shown that the latent heat flux is linear. Applications of the method to lake-effect snowstorms and for verification of boundary-layer models are indicated.

  13. Thermal Comfort Evaluation of a Heat Pump System using Induced-air Supply Unit

    OpenAIRE

    Ling, Jiazhen; Xu, Jian; Aute, Vikrant; Radermacher, Reinhard

    2014-01-01

    Traditional heat pump systems supply conditioned air to space at certain temperatures such as, in summer, about 16°C. When the supply-air temperature drops too low, most occupants tend to feel uncomfortable. On the other hand, a certain amount of dehumidification has to be carried out and sometimes, the velocity of supply-air has to be high which in turn creates a draught. This paper introduces a new air supply method to reduce fan power consumption as well as to improve thermal comfort of oc...

  14. Influence of Heat Treatment on Color Change of Poplar

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, Populus tomentosa was used as samples for heat treatment in order to find the initial effect rule of color change, when the temperature rose to180, 200 and 220 oC and the time was kept for 1, 2 and 3 h, respectively. The results are shown as follows: The color of treated wood can be changed obviously by the heat treatment. Under the same temperature, the color saturation becomes smaller and the difference of color becomes more obvious with the increase of the keeping time. Lightness and color...

  15. Processing tomato concentrates by heat treatment and ionization

    International Nuclear Information System (INIS)

    It is analyzed what dosis of irradiation is required for the processing of tomato paste leaving the evaporator and what are the differences in composition and quality of the puree processed by heat treatment i.e. by irradiation, during a six months storage. It has been found that a dosis of 1.0x104 Gray is satisfactory in obtaining complete sterility. Figures presenting the changes in sugar content, water soluble colour, acid content and HMF content, further results of sensorial scoring prove the quality of irradiated samples being generally not higher than that of the samples processed by traditional heat treatment. (author)

  16. The New S-RAM Air Variable Compressor/Expander for Heat Pump and Waste Heat to Power Application

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jestings, Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Conde, Ricardo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-05-23

    S-RAM Dynamics (S-RAM) has designed an innovative heat pump system targeted for commercial and industrial applications. This new heat pump system is more efficient than anything currently on the market and utilizes air as the refrigerant instead of hydrofluorocarbon (HFC) refrigerants, leading to lower operating costs, minimal environmental costs or concerns, and lower maintenance costs. The heat pumps will be manufactured in the United States. This project was aimed at determining the feasibility of utilizing additive manufacturing to make the heat exchanger device for the new heat pump system. ORNL and S-RAM Dynamics collaborated on determining the prototype performance and subsequently printing of the prototype using additive manufacturing. Complex heat exchanger designs were fabricated using the Arcam electron beam melting (EBM) powder bed technology using Ti-6Al-4V material. An ultrasonic welding system was utilized in order to remove the powder from the small openings of the heat exchanger. The majority of powder in the small chambers was removed, however, the amount of powder remaining in the heat exchanger was a function of geometry. Therefore, only certain geometries of heat exchangers could be fabricated. SRAM Dynamics evaluated a preliminary heat exchanger design. Although the results of the additive manufacturing of the heat exchanger were not optimum, a less complex geometry was demonstrated. A sleeve valve was used as a demonstration piece, as engine designs from S-RAM Dynamics require the engine to have a very high density. Preliminary designs of this geometry were successfully fabricated using the EBM technology.

  17. Cooling, freezing and heating with the air cycle: air as the ultimate green refrigerant

    NARCIS (Netherlands)

    Verschoor, M.J.E.

    2000-01-01

    Due to the recent concern about the damage that CFCs cause to the environment (ozone layer, global warming) and the absence of commonly acceptable alternative refrigerants, the search for alternative refrigeration concepts is going on. Air as refrigerant in the Joule-Brayton cycle (air cycle) is one

  18. Thermal performance analysis of optimized hexagonal finned heat sinks in impinging air jet

    Science.gov (United States)

    Yakut, Kenan; Yeşildal, Faruk; Karabey, Altuǧ; Yakut, Rıdvan

    2016-04-01

    In this study, thermal performance analysis of hexagonal finned heat sinks which optimized according to the experimental design and optimization method of Taguchi were investigated. Experiments of air jet impingement on heated hexagonal finned heat sinks were carried out adhering to the L18(21*36) orthogonal array test plan. Optimum geometries were determined and named OH-1, OH-2. Enhancement efficiency with the first law of thermodynamics was analyzed for optimized heat sinks with 100, 150, 200 mm heights of hexagonal fin. Nusselt correlations were found out and variations of enhancement efficiency with Reynolds number presented in η-Re graphics.

  19. Air Circulation and Heat Exchange Under Reduced Pressures

    Science.gov (United States)

    Rygalov, V.; Wheeler, R.; Dixon, M.; Fowler, P.; Hillhouse, L.

    2010-01-01

    Heat exchange rates decrease non-linearly with reductions in atmospheric pressure. This decrease creates risk of thermal stress (elevated leaf temperatures) for plants under reduced pressures. Forced convection (fans) significantly increases heat exchange rate under almost all pressures except below 10 kPa. Plant cultivation techniques under reduced pressures will require forced convection. The cooling curve technique is a reliable means of assessing the influence of environmental variables like pressure and gravity on gas exchange of plant. These results represent the extremes of gas exchange conditions for simple systems under variable pressures. In reality, dense plant canopies will exhibit responses in between these extremes. More research is needed to understand the dependence of forced convection on atmospheric pressure. The overall thermal balance model should include latent and radiative exchange components.

  20. Hourly Calculation Method of Air Source Heat Pump Behavior

    OpenAIRE

    Ludovico Danza; Lorenzo Belussi; Italo Meroni; Michele Mililli; Francesco Salamone

    2016-01-01

    The paper describes an hourly simplified model for the evaluation of the energy performance of heat pumps in cooling mode maintaining a high accuracy and low computational cost. This approach differs from the methods used for the assessment of the overall energy consumption of the building, normally placed in the so-called white or black box models, where the transient conduction equation is deterministically and stochastically solved, respectively. The present method wants to be the expressi...

  1. Rapid Heat Treatment of Aluminum High-Pressure Diecastings

    Science.gov (United States)

    Lumley, R. N.; Polmear, I. J.; Curtis, P. R.

    2009-07-01

    Recently, it has been demonstrated that common high-pressure diecasting (HPDC) alloys, such as those based on the Al-Si-Cu and Al-Si-Mg-(Cu) systems, may be successfully heat treated without causing surface blistering or dimensional instability. In some compositions, the capacity to exploit age hardening may allow the proof stress values to be doubled when compared to the as-cast condition. This heat treatment procedure involves the use of severely truncated solution treatment cycles conducted at lower than normal temperatures, followed by quenching and natural or artificial aging. The potential therefore exists to develop and evaluate secondary HPDC alloys designed specifically for rapid heat treatment, while still displaying high castability. This article reports results of an experimental program in which responses of various alloy compositions to age hardening have been investigated with the primary aim of further reducing the duration and cost of the heat treatment cycle while maintaining high tensile properties. Composition ranges have been established for which values of 0.2 pct proof stress exceeding 300 MPa ( i.e., increases of ~100 pct above as-cast values) can be achieved using a procedure that involves a total time for solution treatment plus age hardening of only 30 minutes. This rapid aging behavior is shown to be related to precipitation of the complex Q' phase, which forms primarily when Mg contents of the alloys are above ~0.2 wt pct.

  2. Effect of heterogenous and homogenous air gaps on dry heat loss through the garment.

    Science.gov (United States)

    Mert, Emel; Psikuta, Agnes; Bueno, Marie-Ange; Rossi, René M

    2015-11-01

    In real life conditions, the trapped air between the human body and the garment has uneven shape and vary over the body parts as a consequence of the complex geometry of the human body. However, the existing clothing models assume uniform air layer between the human body and the garment or its full contact, which may cause large error in the output of simulations. Therefore, the aim of this study was to investigate the effect of a heterogeneous vertical air gap with different configuration of folds (size and frequency) on dry heat loss using a heated cylinder (Torso). It was found that the presence of folds in the garment led to an increased heat loss from the body in comparison to a homogeneous air gap of comparable size. Interestingly, the size of folds did not have an influence on the dry heat loss. Additionally, the effect of the contact area on dry heat loss became important when exceeding a threshold of about 42%. The results from this study are useful for modelling of a realistic dry heat loss through the clothing and contribute to the improvement of design of protective and active sport garments. PMID:25796204

  3. 基于复合热源的热泵型空调器%Heat pump air conditioner based on multiple heat sources

    Institute of Scientific and Technical Information of China (English)

    吴国珊; 凌勋

    2012-01-01

    It is proposed that the air-water multiple heat sources could be the heat source of heat pump air conditioner. Based on the current study condition, the heat pump air conditioner which has a air/family waste water multiple heat source is preliminary designed. The working cycle and characteristics of the air conditioner are analyzed by using the thermodynamic principle. The results show that the refrigeration performance of the heat pump air conditioner is better than that of air source heat pump air conditioner, the heating performance and the situation which the outdoor heat exchanger frosts are improved.%提出将空气-水作为热泵型空调器的复合热源.根据当前的研究状况,初步设计空气-水复合热源热泵型空调器,利用热力学原理分析该空调器的工作循环和特点,结果表明该空调器的制冷性能高于空气源热泵空调器,制热和室外换热器结霜状况得到一定改善.

  4. Theoretical evaluation on the impact of heat exchanger in Advanced Adiabatic Compressed Air Energy Storage system

    International Nuclear Information System (INIS)

    Highlights: • A multi-stage AA-CAES system model is established based on thermodynamic theory. • Four Cases about pressure loss and effectiveness of heat exchanger are investigated. • The impact of pressure loss on conversion of heat energy in TES is more sensitive. • The impact of heat exchanger effectiveness in charge process on system is stronger. • Pressure loss in heat exchanger affects the change trends of system efficiency. - Abstract: Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) is a large-scale energy storage system based on gas turbine technology and thermal energy storage (TES). Electrical energy can be converted into internal energy of air and heat energy in TES during the charge process, while reverse energy conversion proceeds during discharge process. The performance of AA-CAES system requires further improvement in order to increase efficiency. In this paper, a multi-stage AA-CAES system model is established, and the influence of effectiveness and pressure loss in heat exchanger on energy conversion and utilization efficiency of AA-CAES system is analyzed theoretically based on the theory of thermodynamics. Four Cases about effectiveness and pressure loss of heat exchanger are investigated and compared with each other. It is found that effectiveness and pressure loss of heat exchanger are directly related to energy conversion and utilization in AA-CAES system. System efficiency changes with the variation of heat exchanger effectiveness and the impact of pressure loss on conversion of heat energy in TES is more sensitive than that of internal energy of air. Pressure loss can cause the complexity of system efficiency change. With appropriate selection of the values of heat exchanger effectiveness for both charge and discharge processes, an AA-CAES system with a higher efficiency could be expected

  5. Effects of Heat Treatments on Microstructures and Mechanical Properties of Dual Phase ODS Steels for high Temperature Strength

    International Nuclear Information System (INIS)

    In the present study, the effects of various heat treatments on the microstructure and mechanical properties of dual phase ODS steels were investigated to enhance the high strength at elevated temperature. Dual phase ODS steels have been designed by the control of ferrite and austenite formers, i. e., Cr, W and Ni, C in Fe-based alloys. The ODS steels were fabricated by mechanical alloying and a hot isostatic pressing process. Heat treatments, including hot rolling-tempering and normalizing-tempering with air- and furnace-cooling, were carefully carried out. It was revealed that the grain size and oxide distributions of the ODS steels can be changed by heat treatment, which significantly affected the strengths at elevated temperature. Therefore, the high temperature strength of dual phase ODS steel can be enhanced by a proper heat treatment process with a good combination of ferrite grains, nano-oxide particles, and grain boundary sliding

  6. Effects of Heat Treatments on Microstructures and Mechanical Properties of Dual Phase ODS Steels for high Temperature Strength

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon; Choi, Byoungkwon; Han, Changhee; Kang, Sukhoon; Jang, Jinsung; Jeong, Yonghwan; Kim, Taekyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-11-15

    In the present study, the effects of various heat treatments on the microstructure and mechanical properties of dual phase ODS steels were investigated to enhance the high strength at elevated temperature. Dual phase ODS steels have been designed by the control of ferrite and austenite formers, i. e., Cr, W and Ni, C in Fe-based alloys. The ODS steels were fabricated by mechanical alloying and a hot isostatic pressing process. Heat treatments, including hot rolling-tempering and normalizing-tempering with air- and furnace-cooling, were carefully carried out. It was revealed that the grain size and oxide distributions of the ODS steels can be changed by heat treatment, which significantly affected the strengths at elevated temperature. Therefore, the high temperature strength of dual phase ODS steel can be enhanced by a proper heat treatment process with a good combination of ferrite grains, nano-oxide particles, and grain boundary sliding.

  7. Numerical Simulation and Experimental Studies of Air Treatment Process with Water Spray of One Row Counter Flow

    Institute of Scientific and Technical Information of China (English)

    倪波

    2001-01-01

    The present work is focused on heat and mass transfer in a direct evaporative air cooler of one row counter flow spray. Models of the two-phase flow in such a air treatment system have been developed. The fields of temperature and relative humidity in spray chamber, as well as the trajectories of sprayed drops have been obtained by numerical method. Experiments aiming at quantifying the system performance and its influence factors have been conducted. It indicates that the increase of air velocity and water/air ratio while the decrease of nozzle density are favorable. The performance of the system of parallel flow spray and counter flow spray have been compared by means of humidifying efficiency. Comparison between numerical simulation and experimental results demonstrate good agreement for outlet air temperature with a maximum error of 8% observed for air relative humidity.

  8. Effect of heat treatment on Jahn–Teller distortion and magnetization in Cu ferrite nanoparticles

    International Nuclear Information System (INIS)

    Highlights: ► Cu ferrite nanoparticles were produced by a wet chemical method. ► Heat treatment was performed using an electric furnace. ► Tetragonal Cu ferrite with Jahn–Teller distortion or cubic structure was obtained, depending on the heat treatment method. ► X-ray absorption fine structure analysis was performed to support XRD measurements. ► The suppression and expression of the Jahn–Teller distortion seems to be dependent of the ambient pressure of the SiO2 cage. - Abstract: Cu ferrite (CuFe2O4) nanoparticles were prepared by a wet chemical method. Heat treatment was performed using an electric furnace in an air atmosphere at temperatures between 973 and 1223 K. Some samples were quenched after annealing; three different quenching methods were adopted. The particle diameters, as estimated from X-ray diffraction (XRD) patterns, ranged from 6 to 37 nm. Tetragonal Cu ferrite with Jahn–Teller distortion or cubic Cu ferrite without Jahn–Teller distortion was obtained, depending on the heat treatment method used. X-ray absorption fine structure (XAFS) spectra supported the observed structural differences. Magnetization measurements were performed on each sample at a DC field of ±50 kOe. The saturation magnetization of cubic Cu ferrite was greater than that of the distorted cubic structure.

  9. Using geothermal energy to heat a portion of a formation for an in situ heat treatment process

    Science.gov (United States)

    Pieterson, Roelof; Boyles, Joseph Michael; Diebold, Peter Ulrich

    2010-06-08

    Methods of using geothermal energy to treat subsurface formations are described herein. Methods for using geothermal energy to treat a subsurface treatment area containing or proximate to hydrocarbons may include producing geothermally heated fluid from at least one subsurface region. Heat from at least a portion of the geothermally heated fluid may be transferred to the subsurface treatment area to heat the subsurface treatment area. At least some hydrocarbon fluids may be produced from the formation.

  10. EFFECT OF HEAT TREATMENT ON SOYBEAN PROTEIN SOLUBILITY

    Directory of Open Access Journals (Sweden)

    RODICA CĂPRIŢĂ

    2013-12-01

    Full Text Available The use of soybean products in animal feeds is limited due to the presence of antinutritional factors (ANF. Proper heat processing is required to destroy ANF naturally present in raw soybeans and to remove solvent remaining from the oil extraction process. Over and under toasting of soybean causes lower nutritional value. Excessive heat treatment causes Maillard reaction which affects the availability of lysine in particular and produces changes to the chemical structure of proteins resulting in a decrease of the nutritive value. The objective of this study was to evaluate the effect of heating time on the protein solubility. The investigation of the heating time on protein solubility in soybean meal (SBM revealed a negative correlation (r = -0.9596. Since the urease index is suitable only for detecting under processed SBM, the protein solubility is an important index for monitoring SBM quality.

  11. Impact Toughness and Heat Treatment for Cast Aluminum

    Science.gov (United States)

    Lee, Jonathan A (Inventor)

    2016-01-01

    A method for transforming a cast component made of modified aluminum alloy by increasing the impact toughness coefficient using minimal heat and energy. The aluminum alloy is modified to contain 0.55%-0.60% magnesium, 0.10%-0.15% titanium or zirconium, less than 0.07% iron, a silicon-tomagnesium product ratio of 4.0, and less than 0.15% total impurities. The shortened heat treatment requires an initial heating at 1,000deg F. for up to I hour followed by a water quench and a second heating at 350deg F. to 390deg F. for up to I hour. An optional short bake paint cycle or powder coating process further increase.

  12. Study on the natural convection heat transfer characteristics in the air duct

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. K.; Lee, Y. B.; Choi, S. K.; Hwang, J. S.; Nam, H. Y. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    Temperature distribution measurements in the mockup apparatus of reactor vessel were performed to determine the effective thermal conductivity of porous media with different geometry and to obtain the experimental data for the heat transfer processes by natural convection occurring in the air duct. The temperature distributions at four separated sections with different arrangements of porous media have different slopes according to the geometrical configuration. From the measured temperature distribution, effective thermal conductivity have been derived using the least square fitting method. The test at air duct was performed to the high heat removal at 3.4kW/m{sup 2} by the natural convection from the outer wall to the air. And also the temperature distributions in the sir duct agree well with the 1/7th power-law turbulent temperature distribution. The obtained heat transfer data have been compared with the Shin`s and Sieger`s correlations. 10 refs., 6 figs. (Author)

  13. Study on a decay heat removal system of light water reactors using air coolers

    International Nuclear Information System (INIS)

    In the present work, a passive decay heat removal system for light water reactors (LWRs) based on a new concept is studied referring to an air cooling system (ACS) of the fast breeder reactor Monju. The present study will contribute to the reduction of severe accident risks of nuclear power plants. In this system, a blower for an air cooler (AC) is operated using the rotation of a small steam turbine by generated steam in order to cool heat transfer tubes by forced convection of air. The purpose of the present work is to investigate the plant transient caused by a station blackout (SBO) using the plant system code NETFLOW++ and decay heat removal characteristics. A calculation model is the Advanced Boiling Water Reactor (ABWR) in Japan. (author)

  14. Laser Heat Treatment on Gear Surface and Its Practical Application

    Institute of Scientific and Technical Information of China (English)

    MA Chun-yin; DAI Zhong-sen; SU Bao-rong

    2004-01-01

    Making gears with hardened tooth flank is one of the important developments in gear manufacturing. However, the conventional heat treating methods have a common shortcoming--producing big deformation. In this work, we demonstrate, by study, experiment and practical use, that not only has the laser heat treatment solved the difficult problems in conventional technique, but also it has great superiority. The use cases proved that the laser-treated gears are able to substitute for all the gears including gears with complicated shape, high precision and high performance imported gears and all those gears that cannot be manufactured by conventional methods. Moreover, our laser-treated gears have won quite good economic benefit.Obviously, the laser heat treatment for gears is a highly competitive technique having good prospects.

  15. Designing homogenization-solution heat treatments for single crystal superalloys

    International Nuclear Information System (INIS)

    The conventional stepwise solutionizing method is studied for an experimental Ni-base single crystal superalloy using metallography, eutectic fraction analysis and electron microprobe analysis. The temperature range for solutionizing the alloy is determined by combinations of holding time and temperature. The effects of long isothermal holding within and above this solutioning temperature range are presented. Heat treatment steps below the γ'-solvus temperature stabilize the eutectic phase, while steps above the solvus temperature improve the homogenization and reduce eutectic phase fraction. There is a finite nucleation time for incipient melting which is a function of holding temperature above the equilibrium solidus of the alloy. A prolonged isothermal holding above the equilibrium solidus temperature causes up-hill diffusion at the eutectic region leading to incipient melting. A new homogenization-solution heat treatment approach with continuous heating between solvus and solidus is proposed.

  16. Welding of carbon steel vessels without post weld heat treatment

    International Nuclear Information System (INIS)

    The methods available for the repair welding of carbon steel vessels without post weld heat treatment and with particular reference to service in a sour environment have been reviewed. All the available techniques have the common aim of providing adequate properties in the weld metal and heat affected zone without the need for a full post weld stress relief. The heat that is required to provide the necessary metallurgical changes comes, therefore, from an alternate source. The two sources used are heat from suitably placed subsequent weld passes or from localized external heat sources. The technique presently being used by Ontario Hydro to repair vessels subject to sour service utilizes both a high preheat and a welding technique which is designed to temper the heat affected zone formed in the base material by the first weld pass. This technique is an improvement over the 'half bead' techniques given in the ASME X1 code and has been shown to be capable of reducing the hardness of the heat affected zone to an acceptable level. Certain recommendations have been made which could improve control of the technique presently used by Ontario Hydro and provide measurable parameters between procedural tests and the actual weld repairs

  17. Computer programme for prediction steel parameters after heat treatment

    Directory of Open Access Journals (Sweden)

    J. Trzaska

    2007-10-01

    Full Text Available Purpose: The purpose of this paper is presentation of the computer program for calculating the Continuous Cooling Transformation diagrams for constructional and engineering steels.Design/methodology/approach: The computer program uses the artificial neural networks for prediction steel properties after heat treatment. Input data are chemical composition and austenitizing temperature. Results of calculation consist of temperature of the beginning and the end of transformation in the cooling rate function, the volume fraction of structural components and hardness of steel cooled from austenitizing temperature with a fixed rate.Findings: The algorithm can be use in designing new chemical compositions of steels with assumed hardness after heat treatment.Research limitations/implications: The created method for designing chemical compositions is limited by ranges of mass concentrations of elements. The methodology demonstrated in the paper makes possibility to add new steels to the system.Practical implications: The method may be used in computer steel selection systems for machines parts manufactured from constructional or engineering steels subjected to heat treatment.Originality/value: The presented computer program can be used for selecting steel with required structure after heat treatment.

  18. 7 CFR 58.236 - Pasteurization and heat treatment.

    Science.gov (United States)

    2010-01-01

    ... destruction. Condensed milk products made from pasteurized milk may be transported to a drying plant, provided... Service 1 Operations and Operating Procedures § 58.236 Pasteurization and heat treatment. All milk and buttermilk used in the manufacture of dry milk products and modified dry milk products shall be...

  19. Hourly Calculation Method of Air Source Heat Pump Behavior

    Directory of Open Access Journals (Sweden)

    Ludovico Danza

    2016-04-01

    Full Text Available The paper describes an hourly simplified model for the evaluation of the energy performance of heat pumps in cooling mode maintaining a high accuracy and low computational cost. This approach differs from the methods used for the assessment of the overall energy consumption of the building, normally placed in the so-called white or black box models, where the transient conduction equation is deterministically and stochastically solved, respectively. The present method wants to be the expression of the grey box model, taking place between the previous approaches. The building envelope is defined using a building thermal model realized with a 3 Resistance 1 Capacitance (3R1C thermal network based on the solution of the lumped capacitance method. The simplified model evaluates the energy efficiency ratio (EER of a heat pump through the determination of the hourly second law efficiency of a reversed Carnot cycle. The results of the simplified method were finally compared with those provided by EnergyPlus, a dynamic building energy simulation program, and those collected from an outdoor test cell in real working conditions. The results are presented in temperatures and energy consumptions profiles and are validated using the Bland-Altman test.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-15

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

  1. A Comparative Cycle and Refrigerant Simulation Procedure Applied on Air-Water Heat Pumps

    DEFF Research Database (Denmark)

    Mader, Gunda; Palm, Björn; Elmegaard, Brian

    2012-01-01

    small capacity heat pump applications today. Many of the applicable refrigerants also reach their technical limits regarding low vapor pressure for very low source temperatures and high discharge temperatures for high sink temperatures. These issues are especially manifest for air-water heat pumps. Many...... alternative cycle setups and refrigerants are known to improve the energy efficiency of a vapor compression cycle and reduce discharge temperatures. However not all of them are feasible for small capacity heat pumps from a cost and complexity point of view. This paper presents a novel numerical approach......A vapor compression heat pump absorbs heat from the environment at a low temperature level and rejects heat at a high temperature level. The bigger the difference between the two temperature levels the more challenging is it to gain high energy efficiency with a basic cycle layout as found in most...

  2. Heterogeneous Photocatalysis: Fundamentals and Application for Treatment of Polluted Air

    Directory of Open Access Journals (Sweden)

    Tomašić, V.

    2011-07-01

    the photocatalytic degradation of organic compounds is generally more efficient in the gas phase than in the liquid phase, and the fact that the treatment cost may be significantly lower than that of the water phase photocatalytic treatment, the scientific interest has shifted towards the application of photocatalysis for air treatment. This paper describes the basics of heterogeneous photocatalysis, mainly on TiO2 and the application of photocatalytic processes for air treatment purposes. Review of more interesting practical application of heterogeneous photocatalysis for the treatment of polluted air is presented. Special efforts are made to describe the technical aspects of the photocatalytic processes and to characterize different photocatalytic reactors in use for air treatment.

  3. Compressed air energy storage with waste heat export: An Alberta case study

    International Nuclear Information System (INIS)

    Highlights: • Export of compression waste heat from CAES facilities for municipal heating can be profitable. • D-CAES concept has a negative abatement cost of −$40/tCO2e under the studied circumstances. • Economic viability of D-CAES highly depends on distance between air storage site and heat load. - Abstract: Interest in compressed air energy storage (CAES) technology has been renewed driven by the need to manage variability form rapidly growing wind and solar capacity. Distributed CAES (D-CAES) design aims to improve the efficiency of conventional CAES through locating the compressor near concentrated heating loads so capturing additional revenue through sales of compression waste heat. A pipeline transports compressed air to the storage facility and expander, co-located at some distance from the compressor. The economics of CAES are strongly dependant on electricity and gas markets in which they are embedded. As a case study, we evaluated the economics of two hypothetical merchant CAES and D-CAES facilities performing energy arbitrage in Alberta, Canada using market data from 2002 to 2011. The annual profit of the D-CAES plant was $1.3 million more on average at a distance of 50 km between the heat load and air storage sites. Superior economic and environmental performance of D-CAES led to a negative abatement cost of −$40/tCO2e. We performed a suite of sensitivity analyses to evaluate the impact of size of heat load, size of air storage, ratio of expander to compressor size, and length of pipeline on the economic feasibility of D-CAES

  4. Analysis of air-to-water heat pump in cold climate: comparison between experiment and simulation

    Directory of Open Access Journals (Sweden)

    Karolis Januševičius

    2015-10-01

    Full Text Available Heat pump systems are promising technologies for current and future buildings and this research presents the performance of air source heat pump (ASHP system. The system was monitored, analysed and simulated using TRNSYS software. The experimental data were used to calibrate the simulation model of ASHP. The specific climate conditions are evaluated in the model. It was noticed for the heating mode that the coefficient of performance (COP varied from 1.98 to 3.05 as the outdoor temperature changed from –7.0 ºC to +5.0 ºC, respectively. TRNSYS simulations were also performed to predict seasonal performance factor of the ASHP for Vilnius city. It was identified that seasonal performance prediction could be approximately 15% lower if frost formation effects are not included to air-water heat pump simulation model.

  5. Dynamic heat transfer model for temperature drop analysis and heat exchange system design of the air-powered engine system

    International Nuclear Information System (INIS)

    In the operation process of an air-powered engine (APE) system, temperature drops happening in critical locations can influence the engine's performance negatively, and even lead to the ice blocking problem. To predict temperature drops during the operation, firstly, the thermodynamic model of the APE and a calculation method for equivalent air temperatures at intake and exhaust ports are described. The cooling mechanism of the pressure-reducing process is analyzed. Then a simplified calculation model of the throttling effect for dynamic temperature analysis is proposed. Furthermore, a complete dynamic model of the APE system is established, by considering models mentioned above and models of the pressure tank and the supply pipeline as well. The model's feasibility on the temperature drop analysis is verified by comparing with corresponding experiments. Simulation of a practical APE system is carried out. Under specific parameter settings, temperature drops of critical locations in the system are predicted. On this basis, the supply system of compressed air is modified and a principle structure of the heat exchange system for the APE system is proposed. The analysis results in this paper can provide a theoretical support for the design of the heat exchange system. - Highlights: • A simplified calculation method of throttling effect for dynamic temperature analysis is proved to be effective in a pressure range from 30 MPa to 1 MPa. • A thermodynamic model of the air powered engine(APE) and a calculation method for equivalent air temperatures are proposed. • Prediction method of the temperature drops of critical positions in the APE system are studied. • A principle structure of the heat exchange system for the APE system is proposed

  6. Key Technology and Experimental Results of the Clean Air Heated Facility for Supersonic Combustion

    Institute of Scientific and Technical Information of China (English)

    ZHONG Zipeng; SONG Wenyan; LE Jialing

    2009-01-01

    The scramjet, which is the propulsion of hypersonic vehicle, has become the focus in many military developed countries. The ground tests play an important role in the research of scramjet. There is defect of test medium contamination (the thermochemical characteristic of the ground test medium is different from that of the flight medium) in existing ground test facilities for scramjet combustor experiment. To solve the problem of test medium contamination, the first clean air heated facility of China for scramjet combustor experiment is designed. The key technology of designing the clean air heated facility is summarized. By using bypass duct, combustor model is protected from high temperature. To reduce the switching time between main duct and bypass duct, solenoid valve and water-cooled system were used. Having centrosymmetric structure, the heat radiating area of the facility and heat loss of the facility are much lower than others. Clean air heated facility is adopted to conduct experiment, which is the first experiment of China in clean air inflow, research on hydrogen-fueled and ethylene-fueled ignition and combustion for scramjet combustor at different equivalence ratio. Successful ignition and sustained combustion of hydrogen has been achieved. Successful ethylene ignition and sustained main stream combustion is achieved with normal fuel injection and taking hydrogen as pilot flame. Experiment result shows that the wall pressure of combustor model rises when the equivalence ratio of hydrogen rises. As the wall pressure of combustor model rises, the pressure disturbance influences the shock train in the upstream.

  7. Formation of inorganic nanofibers by heat-treatment of poly(vinyl alcohol-zirconium compound hybrid nanofibers

    Directory of Open Access Journals (Sweden)

    Nakane K.

    2013-01-01

    Full Text Available Poly(vinyl alcohol-zirconium compound hybrid nanofibers (precursors were formed by electrospinning employing water as a solvent for the spinning solution. The precursors were converted into oxide (ZrO2, carbide (ZrC or nitride (ZrN nanofibers by heating them in air, Ar or N2 atmospheres. Monoclinic ZrO2 nanofibers with high-specific surface area were obtained by heat-treatment of the precursors in air. ZrC and ZrN nanofibers could be obtained below theoretical temperatures calculated from thermodynamics data.

  8. Review on Conventional Air Conditioning, Alternative Refrigerants, and CO2 Heat Pumps for Vehicles

    OpenAIRE

    Moo-Yeon Lee; Dong-Yeon Lee

    2013-01-01

    With the reinforced ODP and GWP regulations, clean refrigerants including CO2, energy saving technology for fuel economy, especially focused on development and control strategy for the effective air conditioning system, and heat pump for vehicles have been widely investigated. Recently, the automotive CO2 heat pump for the next generation vehicles as an alternative to that of internal combustion engines has been evaluated and studied as a good option. In this paper, first part is reviewed on ...

  9. CFD numerical simulation of air natural convection over a heated cylindrical surface

    Science.gov (United States)

    Flori, M.; Vîlceanu, L.

    2015-06-01

    In this study a CFD numerical simulation is used to describe the fluid flow and heat transfer in air surrounding a heated horizontal cylinder. The model is created in 2D space dimension involving a finite element solver of Navier-Stokes equations. As natural convection phenomenon is induced by a variable fluid density field with temperature rising, the Boussinesq approximation was coupled to the model.

  10. Heat transfer performance of fresh-air handing device using earth energy

    Institute of Scientific and Technical Information of China (English)

    刘丽莹; 付祥钊; 孙克春; 张建波; 刘丽; 李金牛

    2009-01-01

    In order to reduce the fresh-air handing energy consumption,a fresh-air handing device using earth energy was presented. The major part is a double pipe soil-air heat exchanger. Its performance was tested in summer and winter. The results show that while the volume of the treated fresh-air is 125 m3/h,in summer,at the outlet of the device,the air temperature is 21.5-24.0 ℃,the air humidity ratio is about 17 g/kg,the greatest temperature drop is about 9 ℃ ,and the largest dehydration quantity is about 6 g/kg. In winter,at the outlet of the device,the air temperature is 15-17 ℃,the air humidity ratio is about 11 g/kg,the largest temperature rise is about 11 ℃,and the largest humidification quantity is about 6 g/kg. Therefore,the application of this new fresh-air handing device can take full advantage of the natural energy,thus effectively reduce the traditional energy consumption for fresh-air handing.

  11. The Effect of Aerodynamic Heating on Air Penetration by Shaped Charge Jets and Their Particles

    Science.gov (United States)

    Backofen, Joseph

    2009-06-01

    The goal of this paper is to present recent work modeling thermal coupling between shaped charge jets and their particles with air while it is being penetrated to form a crater that subsequently collapses back onto the jet. This work complements research published at International Symposia on Ballistics: 1) 1987 - Shaped Charge Jet Aerodynamics, Particulation and Blast Field Modeling; and 2) 2007 - Air Cratering by Eroding Shaped Charge Jets. The current work shows how and when a shaped charge jet's tip and jet particles are softened enough that they can erode in a hydrodynamic manner as modeled in these papers. This paper and its presentation includes models for heat transfer from shocked air as a function of jet velocity as well as heat flow within the jet or particle. The work is supported by an extensive bibliographic search including publications on meteors and ballistic missile re-entry vehicles. The modeling shows that a jet loses its strength to the depth required to justify hydrodynamic erosion when its velocity is above a specific velocity related to the shock properties of air and the jet material's properties. As a result, the portion of a jet's kinetic energy converted at the aerodynamic shock into heating transferred back onto the jet affects the energy deposited into the air through drag and ablation which in turn affect air crater expansion and subsequent collapse back onto the jet and its particles as shown in high-speed photography.

  12. Effect of Air Cleaning Technologies in Conjunction With the Use of Rotary Heat Exchangers in Residential Buildings

    OpenAIRE

    Afshari, Alireza; Bergsøe, Niels Christian; Ekberg, Lars

    2013-01-01

    This study is part of a research project concerning the possibilities of applying efficient air cleaning technologies using rotary heat exchanger in residential buildings. The purpose of this project was to identify and adapt new air-cleaning technologies for implementation in HVAC systems with rotary air-to-air heat exchangers. For this purpose, a mechanical filter with low pressure drop and a 4 cm thick activated carbon filter were selected for testing in a laboratory environment. The measu...

  13. Experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solar absorber

    OpenAIRE

    Hejcik J.; Pech O.; Charvat P.

    2013-01-01

    The paper deals with experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solarabsorber. The main purpose of heat storage in solar thermal systems is to store heat when the supply of solar heat exceeds demand and release it when otherwise. A number of heat storage materials can be used for this purpose; the phase change materials among them. Short-term latent heat thermal storage integrated with the solar absorber can sta...

  14. Microwave heat treatment of natural ruby and its characterization

    Science.gov (United States)

    Swain, S.; Pradhan, S. K.; Jeevitha, M.; Acharya, P.; Debata, M.; Dash, T.; Nayak, B. B.; Mishra, B. K.

    2016-03-01

    Natural ruby (in the form of gemstone) collected from Odisha has been heat-treated by microwave (MW). A 3-kW industrial MW furnace with SiC susceptors was used for the heat treatment. The ruby samples showed noticeable improvements (qualitative), may be attributed to account for the improvement in clarity and lustre. Optical absorption in 200-800 nm range and photoluminescence peak at 693 nm (with 400 nm λ ex) clearly show that subtle changes do take place in the ruby after the heat treatment. Further, inorganic compound phases and valence states of elements (impurities) in the ruby were studied by X-ray diffraction, micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The valence states of the main impurities such as Cr, Fe, and Ti, in the untreated and MW heat-treated ruby, as revealed from XPS, have been discussed in depth. The overall results demonstrate for the first time the effect of fast heating like MW on the microstructural properties of the gemstone and various oxidation states of impurity elements in the natural ruby.

  15. Experimental investigation of the influence of the air jet trajectory on convective heat transfer in buildings equipped with air-based and radiant cooling systems

    DEFF Research Database (Denmark)

    Le Dreau, Jerome; Heiselberg, Per; Jensen, Rasmus Lund

    2015-01-01

    -state and dynamic conditions. With the air-based cooling system, a dependency of the convective heat transfer on the air jet trajectory has been observed. New correlations have been developed, introducing a modified Archimedes number to account for the air flow pattern. The accuracy of the new correlations has been...

  16. Energy consumption modeling of air source electric heat pump water heaters

    International Nuclear Information System (INIS)

    Electric heat pump air source water heaters may provide an opportunity for significant improvements in residential water heater energy efficiency in countries with temperate climates. As the performance of these appliances can vary widely, it is important for consumers to be able to accurately assess product performance in their application to maximise energy savings and ensure uptake of this technology. For a given ambient temperature and humidity, the performance of an air source heat pump water heater is strongly correlated to the water temperature in or surrounding the condenser. It is therefore important that energy consumption models for these products duplicate the real-world water temperatures applied to the heat pump condenser. This paper examines a recently published joint Australian and New Zealand Standard, AS/NZS 4234: 2008; Heated water systems - Calculation of energy consumption. Using this standard a series TRNSYS models were run for several split type air source electric heat pump water heaters. An equivalent set of models was then run utilizing an alternative water use pattern. Unfavorable errors of up to 12% were shown to occur in modeling of heat pump water heater performance using the current standard compared to the alternative regime. The difference in performance of a model using varying water use regimes can be greater than the performance difference between models of product.

  17. Heat recovery in air conditioning systems in frost-free season with using adiabatic cooling. Capacities overview

    Directory of Open Access Journals (Sweden)

    S.V. Chuduk

    2011-01-01

    Full Text Available In article the review of the information on possibilities of use of recuperators of heat is presented for the warm period of year for air-conditioning system. Aim of heat exchanger work in frost-free season is indirect cooling of incoming air before its input into maintainable premises. It is possible if exhaust air is cooled before its input into heat exchanger . In the article the operational principle of air conditioning system with using of adiabatic air cooling is considered. The data concerned system functioning depending on parameters of microclimate in maintainable premises are given.

  18. CFD-Based Correlation Development For Air Side Performance Of Finned And Finless Tube Heat Exchangers With Small Diameter Tubes

    OpenAIRE

    Bacellar, Daniel; Aute, Vikrant; Radermacher, Reinhard

    2014-01-01

    Air-to-refrigerant heat exchangers are a key component in air-conditioning and heat pump systems. A great deal of effort is spent on the design and optimization of these heat exchangers. One path towards improving their performance is the transition to smaller hydraulic diameter flow channels. This is evident by the recent introduction of microchannel heat exchangers in the stationary HVAC market. Systematic analyses demonstrates a great potential for improvement in terms of size, weight, ref...

  19. Development of an adsorption chiller and heat pump for domestic heating and air-conditioning applications

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Tomas; Henning, Hans-Martin [Fraunhofer Institut for Solar Energy Systems ISE, Heidenhofstrasse 2, 79110 Freiburg (Germany); Mittelbach, Walter [SorTech AG, Weinbergweg 23, 06120 Halle a.d. Saale (Germany)

    2007-09-15

    The scope of this paper is to present the development of a prototype of a small adsorption heat pump working on the adsorption pair silica gel-water. The development of this prototype with remarkable high power densities has been carried out during the last year and is a result of continued joint work on adsorption heat transformation systems carried out at SorTech AG and the Fraunhofer Institute. (author)

  20. Heat strokes: aetiopathogenesis, neurological characteristics, treatment and outcome.

    Science.gov (United States)

    Yaqub, B; Al Deeb, S

    1998-04-01

    Heat stroke is a thermal insult to the cerebral thermoregulatory system controlling heat production and heat dissipation. The thermal insult may be environmental as in 'classic heat stroke' or endogenous as in 'exertional heat stroke' in joggers or runners. The insult will lead to a steady rise in body core temperature to 40 degrees C or more, exhaustion of sweating with hot dry skin and central nervous system disturbances ranging from confusion to deep coma. Multisystem insult will follow leading to a fatal outcome, if not diagnosed and treated promptly. Rapid evaporative cooling and support of vital organs are the essential factors in the management of this condition. If treated early, no sequelae results, however, pancerebellar syndrome and spastic or flaccid paraparesis have been described in a few cases. Limited sun exposure, proper use of sunscreens, adequate fluid and electrolyte replacement and acclimatization are the key factors for prevention. Despite appropriate prevention and prompt treatment, heat stroke is unlikely to be totally prevented, but the mortality has improved dramatically to less than 10%. PMID:9588849

  1. Effects of Heat Treatment on Properties of Polyester Filaments

    Institute of Scientific and Technical Information of China (English)

    王妮; 孙润军

    2003-01-01

    Many properties of polyester filaments such as heat shrinkage, tenacity, elongation at break and etc. are greatly influenced by drawing, so post-drawing is important in downstream processing. As more and more profile fibers and multi.variance fibers used in textile industry, the properties of above two kinds of differential polyester filaments after drawing in different heat conditions were studied. Finally following conclusions were obtained: Firstly, the tenacity and elongation at break decreases with the rise of Tp. Secondly, the tenacity rises but the elongation at break decreases with the increase of Tb.Then, when the Tb is low, both the shrinkage in boiling water and in hot air decreases with the rise of Tp, while, when the Tb is high, both the shrinkage rises with the rise of Tp. The last, both the shrinkage decreases with the rise of Tb.

  2. Effect of heat treatment on antimycotic activity of Sahara honey

    Institute of Scientific and Technical Information of China (English)

    Moussa Ahmed; Saad Aissat; Noureddine Djebli

    2014-01-01

    Objective: To evaluate the influence of the temperature on honey colour, polyphenol contents and antimycotic capacity and to evaluate the correlation between these parameters. Methods:Sahara honey were heated up to 25, 50, 75 and 100 °C for 15, 30 and 60 min, and their colour intensity, polyphenol contents and antimycotic capacity. The Folin-Ciocalteu test was used to determine the total polyphenol contents (TPC). The antimycotic activity was evaluated both by agar diffusion method and micro wells dilution method against the Candida albicans (C. albicans) and Candida glabrata (C. glabrata). Results:Initial values for TPC in Sahara honey ranged from 0.55 to 1.14 mg of gallic acid per kg of honey, with the average value of 0.78 mg of gallic acid per kg of honey. The TPC values after heat-treatment were 0.54 to 1.54 with the average value of 1.49 mg. The minimal inhibitory concentrations before heat-treatment of Sahara honey against C. albicans and C. glabrata ranged from 3.06%-12.5% and 50% respectively. After heat-treatment the minimal inhibitory concentrations between 12.5% and 50% for C. albicans and C. glabrata, respectively. The diameters of inhibition zones of Sahara honey with 50% concentration varied from (12.67-15.00) mm by C. albicans to (14.33-15.67) mm by C. glabrata. The diameters of inhibition zones after heat-treatment at 25 and 50 °C for 15.30 and 60 min ranged from (2.00-18.67) mm by C. albicans to (8.00-16.67) mm by C. glabrata. Statistically significant relations between the TPC and the colour intensity of Sahara honey (r=0.99, P Conclusions:To our knowledge this is the first report on the antimycotic capacity of Sahara honey.

  3. Numerical Study of Forced Air Cooling of a Heated Porous Foam Pyramid Array

    Directory of Open Access Journals (Sweden)

    Anderson Kevin

    2015-01-01

    Full Text Available The current study employs CFD to study the forced air cooling of a pyramid shaped porous foam absorber. Herein, a three by three (33 array of porous foam absorbers heated with an external heat flux is modeled using the differential equations governing heat and fluid flow through porous media based on the Brinkman- Darcy flow equations and an effective thermal conductivity to account for the porous medium. The numerical simulations are carried out using the COMSOL commercial Computational Fluid Dynamics (CFD Finite Element based software package. The results of this verification exercise were within 18% of the prior numerical results and within 14% of the archived measured results. Typical results for the velocity and temperature profiles within the porous foam absorbers are shown. A comparison of Nusselt number between our CFD simulations and the heat transfer theory is plotted, showing agreement on the order of 11%. A parametric study involving heat flux, cooling air inlet velocity, porous foam porosity, and porous foam permeability showed that there is a relationship between porosity and the temperature distribution within the porous media. The primary finding of our study is that the more porous the foam absorber media is, the more dependent the effective thermal conductivity is on the thermal conductivity of the fluid used for cooling. If the fluid is air, which has a very low thermal conductivity, the effective thermal conductivity is decreased as the porosity increases, thus diminishing removal of heat from the foam array via the cooling air stream. Based on the parametric study, the best case operating conditions which may allow the pyramidal foam absorber to stay within the max allowable temperature are as follows: porosity = 0.472, inlet air cooling velocity = 50 m/s.

  4. Computational Fluid Dynamic Modeling of Horizontal Air-Ground Heat Exchangers (HAGHE for HVAC Systems

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2014-12-01

    Full Text Available In order to satisfy the requirements of Directive 2010/31/EU for Zero Energy Buildings (ZEB, innovative solutions were investigated for building HVAC systems. Horizontal air-ground heat exchangers (HAGHE offer a significant contribution in reducing energy consumption for ventilation, using the thermal energy stored underground, in order to pre-heat or pre-cool the ventilation air, in winter and summer, respectively. This is particularly interesting in applications for industrial, commercial and education buildings where keeping the indoor air quality under control is extremely important. Experimental measurements show that, throughout the year, the outside air temperature fluctuations are mitigated at sufficient ground depth (about 3 m because of the high thermal inertia of the soil, the ground temperature is relatively constant and instead higher than that of the outside air in winter and lower in summer. The study aims to numerically investigate the behavior of HAGHE by varying the air flow rate and soil conductivity in unsteady conditions by using annual weather data of South-East Italy. The analysis shows that, in warm climates, the HAGHE brings a real advantage for only a few hours daily in winter, while it shows significant benefits in the summer for the cooling of ventilation air up to several temperature degrees, already by a short pipe.

  5. Recent changes in air temperature, heat waves occurrences, and atmospheric circulation in Northern Africa

    OpenAIRE

    Fontaine, B.; Janicot, Serge; Monerie, P. A.

    2013-01-01

    This study documents the time evolution of air temperature and heat waves occurrences over Northern Africa for the period 1979-2011. A significant warming (1 degrees-3 degrees C), appearing by the mid-1960s over Sahara and Sahel, is associated with higher/lesser frequency of warm/cold temperatures, as with longer duration and higher occurrences of heat waves. Heat waves episodes of at least 4 day duration have been examined after removing the long-term evolution. These episodes are associated...

  6. High saturation magnetization in Fe–0.4 wt% P alloy processed by a two-step heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekhar, S.B.; Prabhu, D., E-mail: dprabhu@arci.res.in; Gopinath, M.; Chandrasekaran, V.; Ramakrishna, M.; Uma, V.; Gopalan, R.

    2013-11-15

    Fe–0.4 wt% P alloy was processed by melting, forging, hot rolling with a subsequent two-step heat treatment and its magnetic properties were compared with those of non-oriented Si-steel. The sample heat treated at 1000 °C for 1 h followed by 500 °C for 30 min air quenched yielded a saturation magnetization (B{sub s}) of 19 kG and a low coercivity (H{sub c}) of 1 Oe. The soft magnetic properties obtained were correlated to the microstructure which showed nano precipitates of Fe{sub 3}P in Fe matrix obtained by the two-step heat treatment procedure. - Highlights: • High saturation induction of 19 kg and high permeability of 3000 (higher than Si steel). • Simple heat treatment procedure. • Industrially scalable process.

  7. Effect of heat treatment on the structure and creep resistance of austenitic Fe–Ni alloy

    Directory of Open Access Journals (Sweden)

    K.J. Ducki

    2011-01-01

    Full Text Available Purpose: The paper addresses the problem of determining the dependence between the initial heat treatment of an austenitic Fe–Ni alloy and its structure, and its creep resistance. Specimens of Fe–Ni alloy were subjected to tests after two variants of heat treatment, i.e. solution heat treatment followed by typical single-stage ageing, and solution heat treatment followed by novel two-stage ageing.Design/methodology/approach: For the investigated Fe–Ni alloy after solution heat treatment in the conditions: 980°C/2h/water, two variants of specimen ageing were applied for a comparison: single-stage ageing (715°C/16h/air and two-stage ageing (720°C/8h + cooling in the furnace up to the temperature of 650°C + 650°C/8h/air. The thermally treated specimens were then subjected to a static tensile test at room and elevated temperatures, and to a creep test in a temperature range of 650-750°C, at stresses from 70 to 340 MPa.Findings: It was found that both, at the room and elevated temperatures, the specimens of Fe–Ni alloy after 2-stage ageing were distinguished by higher strength properties (Y.S, T.S with a little lower plastic properties (EL., R.A. As regards extrapolated results of creep tests, it was found that at a longer exposure time of ca. 10.000 h, specimens after single-stage ageing were characterized with higher creep resistance. Lower creep resistance of the Fe–Ni alloy after two-stage ageing can be explained by increased brittleness of the material in boundary areas.Practical implications: The obtained test results may be used to optimise heat treatment and forecast the operation conditions of products made out of Fe–Ni alloy at an elevated temperature.Originality/value: The study shows a significant effect of the applied ageing variants on mechanical properties and creep resistance of the tested austenitic Fe–Ni alloy.

  8. Advanced air source heat pumps for UK and European domestic buildings

    International Nuclear Information System (INIS)

    To date, the role of heat pumps in UK and European housing has been largely restricted to newbuild, utilising ground source units coupled to under floor heating systems. Therefore the challenge is to develop air source heat pumps whose role is to displace the traditional domestic fossil fuel boiler with the minimum of domestic disturbance by utilising a system capable of heating radiators to sufficient temperatures to maintain comfort and safety. The technical challenges to be overcome at this stage are maintaining high coefficient of performance in spite of the high temperature lift encountered when utilising cold air as a heat source and delivering to a heating circuit originally designed for water at temperatures of 60 oC or more. Options to deliver this include an economised vapour injection compressor and displacing the traditional expansion valve with an expansion turbine and experimental results from both of these approaches will be presented here. - Highlights: → High temperature domestic retrofit heat pumps. → Economised vapour injection. → Rotary compressor-expander.

  9. Performance Analysis of Air-to-Water Heat Pump in Latvian Climate Conditions

    Science.gov (United States)

    Kazjonovs, Janis; Sipkevics, Andrejs; Jakovics, Andris; Dancigs, Andris; Bajare, Diana; Dancigs, Leonards

    2014-12-01

    Strategy of the European Union in efficient energy usage demands to have a higher proportion of renewable energy in the energy market. Since heat pumps are considered to be one of the most efficient heating and cooling systems, they will play an important role in the energy consumption reduction in buildings aimed to meet the target of nearly zero energy buildings set out in the EU Directive 2010/31/EU. Unfortunately, the declared heat pump Coefficient of Performance (COP) corresponds to a certain outdoor temperature (+7 °C), therefore different climate conditions, building characteristics and settings result in different COP values during the year. The aim of this research is to investigate the Seasonal Performance factor (SPF) values of air-to-water heat pump which better characterize the effectiveness of heat pump in a longer selected period of time, especially during the winter season, in different types of residential buildings in Latvian climate conditions. Latvia has four pronounced seasons of near-equal length. Winter starts in mid-December and lasts until mid-March. Latvia is characterized by cold, maritime climate (duration of the average heating period being 203 days, the average outdoor air temperature during the heating period being 0.0 °C, the coldest five-day average temperature being -20.7 °C, the average annual air temperature being +6.2 °C, the daily average relative humidity being 79 %). The first part of this research consists of operational air-towater heat pump energy performance monitoring in different residential buildings during the winter season. The second part of the research takes place under natural conditions in an experimental construction stand which is located in an urban environment in Riga, Latvia. The inner area of this test stand, where air-to-water heat pump performance is analyzed, is 9 m2. The ceiling height is 3 m, all external wall constructions (U = 0.16 W/(m2K)) have ventilated facades. To calculate SPF, the

  10. Experimental evaluation on energy performance of innovative clean air heat pump for indoor environment control in summer and winter seasons

    DEFF Research Database (Denmark)

    Nie, Jinzhe; Fang, Lei; Olesen, Bjarne W.

    2014-01-01

    was developed. Laboratory experimental studies were conducted to investigate its energy performance under different outdoor climates including cold, mild-cold, mild-hot and extremely hot and humid climates. The energy performance of the CAHP was then evaluated by comparing with a conventional air source heat......Based on the air purification capacity of regenerative silica gel rotor, an innovative clean air heat pump (CAHP) was designed, developed and investigated through experimental studies. The CAHP integrated air purification, dehumidification and heating/cooling in one unit. A prototype of the CAHP...... pump. The results showed that to keep same indoor air quality, the CAHP could save substantial amount of energy. For example, compared to the conventional air source heat pump, the CAHP could save up to 59%, 40%, 30% of electricity for ventilation and air conditioning in a test room in summer...

  11. A flexible and low cost experimental stand for air source heat pump for Smart Buildings

    DEFF Research Database (Denmark)

    Crăciun, Vasile S.; Bojesen, Carsten; Blarke, Morten;

    2012-01-01

    prices. A significant part of this challenge may be dealt with in the way space heating, space cooling, and domestic hot water production which is provided to residential and commercial buildings. Air source heat pumps (ASHP) are widely used conversion technologies for providing building thermal energy...... services; cooling, heating, and water heating. ASHP does not have a constant temperature for the primary source like: soil, ground water, or surface water heat pumps. In result, laboratory experiments and tests are faced by the problem of having to handle a wide range of conditions under which the......Energy systems are faced with the challenges of reducing dependency on fossil fuels, while handling increasing penetration levels of intermittent renewables such as wind and solar power. At the same time, the efficient consumption of energy is vital for avoiding the impacts from increasing fuel...

  12. The influence of applied heat treatments on whey protein denaturation

    Directory of Open Access Journals (Sweden)

    Fetahagić Safet

    2002-01-01

    Full Text Available Reconstituted skim milk with 8.01% DM was standardized with 3% skim milk powder and with 3% demineralized whey powder (DWP, respectively. Gained milk samples are named as 8%, 11% and 8%+3%DWP. All samples were heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min, respectively. Untreated milk was used as control. Milk samples were coagulated by glucono-d-lactone (GDL at the temperature of 45ºC until pH 4.60 was reached. Milk nitrogen matter content decreased during heat treatments, but linear relationship between applied heat treatments and nitrogen matter decreasing was not found. Nitrogen matter content of sera gained from both untreated and heat treated milk increased with the increase of milk dry matter content and with the addition of DWP. The higher temperature of applied heat treatment, the smaller sera nitrogen matter content. Nitrogen matter content in sera obtained from untreated milk were 64.90 mg%, 96.80 mg% and 117.3 mg% for milk 8%, 11% and 8%+3.0% DWP, respectively. Sera samples obtained from milk 8% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min had 38.70 mg% 38.30 mg% and 37.20 mg% of nitrogen matter, respectively. Sera samples obtained from milk 11% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min had 55.90 mg%, 52.80 mg% and 51.30 mg% of nitrogen matter, respectively. Sera samples obtained from milk 8% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min had 69.50 mg%, 66.20 mg% and 66.00 mg% of nitrogen matter respectively. Distribution of nitrogen matter from untreated milk to milk sera were 12.01%, 11.14% and 17.69% for milk 8%, 11% and 8%+3.0% DWP respectively. Distribution of nitrogen matter from milk 8% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min to sera samples were 6.99%, 6.72% and 6.59%, respectively. Distribution of nitrogen matter from milk 11% heat treated at 85ºC/10 min, 90ºC/10 min and 95ºC/10 min to sera samples, were 6.02%, 5.32% and 5.21%, respectively

  13. Microwave heat treatment as a substitute for conventional treatment of palm oil fruits

    International Nuclear Information System (INIS)

    Microwave energy has become a sound method of heat treatment because of its high penetration power, cleanliness and possible economic significance. In this research, microwave heat was used as a substitute for conventional blanching method of palm oil fruits. Microwave treatment at 2450 MHz and 800 watts gave very close color and frn,frying characteristics to oil of blanched fruits after one minute exposure time. However, five minutes of microwave heat gave severe husk oil discoloration after 49 hours of deep frying, compared to all oils extracted from fruits treated by either low, microwave exposure time or conventional steam treatment. Kernel oil, after five minutes of microwave treatment, was less discolored than both steam or microwave-treated fruits for one minute. More carotenes and discoloration compounds may be contributed to discoloration during microwave treatments. Oil chemical constants of both husk and kernel oils treated by microwave heat were close to those treated by conventional heat. Further research is needed to investigate detailed oil characteristics and evaluate the feasibility study for using microwave energy, as a substitute for conventional heat in palm oil industry

  14. DEVELOPMENT OF A LINEAR COMPRESSOR FOR AIR CONDITIONERS AND HEAT PUMPS

    Science.gov (United States)

    The report discusses the design, building, testing, and delivering to the Environmental Protection Agency of a linear compressor for operation in a 3.0- ton (10.5 kW) residential air-conditioning and heat pumping system. The compressor design evolved from a linear resonant piston...

  15. Turbidimetric behavior of Butadiene Rubber (BR) solutions in toluene and dichloromethane after heating at open air

    International Nuclear Information System (INIS)

    This paper deals with the turbidimetric behavior of Butadiene Rubber BR solutions, a synthetic rubber, in two solvents (toluene and dichloromethane), after heating at open air till 180 Deg Celsius for optimal polymer cracking conditions. Concentration, solvent and temperature effects have been studied using methanol as precipitant. Butadiene rubber exhibits a high sensitivity to autoxidation with high tendency to reticulation.

  16. Air-sea heat exchange, an element of the water cycle

    Science.gov (United States)

    Chahine, M. T.

    1984-01-01

    The distribution and variation of water vapor, clouds and precipitation are examined. Principal driving forces for these distributions are energy exchange and evaporation at the air-sea interface, which are also important elements of air-sea interaction studies. The overall aim of air-sea interaction studies is to quantitatively determine mass, momentum and energy fluxes, with the goal of understanding the mechanisms controlling them. The results of general circulation simulations indicate that the atmosphere in mid-latitudes responds to changes in the oceanic surface conditions in the tropics. This correlation reflects the strong interaction between tropical and mid-latitude conditions caused by the transport of heat and momentum from the tropics. Studies of air-sea exchanges involve a large number of physica, chemical and dynamical processes including heat flux, radiation, sea-surface temperature, precipitation, winds and ocean currents. The fluxes of latent heat are studied and the potential use of satellite data in determining them evaluated. Alternative ways of inferring heat fluxes will be considered.

  17. Geothermal as a heat sink application for raising air conditioning efficency

    Science.gov (United States)

    Ibrahim, Hesham Safwat Osman Mohamed

    2016-04-01

    Objective: Geothermal applications in heating, ventilation, air-conditioning is a US technology for more than 30 years old ,which saves more than 30% average energy cost than the traditional air-conditioning systems systems. Applying this technology in Middle East and African countries would be very feasible specially in Egypt specially as it suffers Electric crisis --The temperature of the condensers and the heat rejecting equipment is much higher than the Egyptian land at different depth which is a great advantages, and must be measured, recorded, and studied accurately -The Far goal of the proposal is to construct from soil analysis a temperature gradient map for Egypt and , African countries on different depth till 100 m which is still unclear nowadays and must be measured and recorded in databases through researches - The main model of the research is to study the heat transfer gradient through the ground earth borehole,grout,high density polyethylene pipes , and water inlet temperature which affect the electric efficiency of the ground source heat pump air conditioning unit Impact on the Region: Such research result will contribute widely in Energy saving sector specially the air conditioning sector in Egypt and the African countries which consumes more than 30% of the electric consumption of the total consumption . and encouraging Green systems such Geothermal to be applied

  18. Improved Modeling of Residential Air Conditioners and Heat Pumps for Energy Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Winkler, J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kruis, N. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Christensen, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Brandemuehl, M. [Univ. of Colorado, Boulder, CO (United States)

    2013-01-01

    This report presents improved air conditioner and heat pump modeling methods in the context of whole-building simulation tools, with the goal of enabling more accurate evaluation of cost-effective equipment upgrade opportunities and efficiency improvements in residential buildings.

  19. Performance of Chilled Beam with Radial Swirl Jet and Diffuse Ceiling Air Supply in Heating Mode

    DEFF Research Database (Denmark)

    Bertheussen, Bård; Mustakallio, Panu; Melikov, Arsen Krikor;

    2013-01-01

    The performance of diffuse ceiling air supply and chilled beam with swirl jet (CSW) in heating mode (winter situation) was studied and compared with regard to the generated indoor environment. An office mock-up with one occupant was simulated in a test room (4.5 x 3.95 x 3.5 m3 (L x W x H...

  20. Heating, Air Conditioning and Refrigeration. Vocational Education Curriculum Guide. Industrial and Technical Education.

    Science.gov (United States)

    West Virginia State Vocational Curriculum Lab., Cedar Lakes.

    This curriculum guide contains 17 units that provides the basic curriculum components required to develop lesson plans for the heating, air conditioning, and refrigeration curriculum. The guide is not intended to be a complete, self-contained curriculum, but instead provides the teacher with a number of informational items related to the learning…

  1. Radon mitigation in schools utilising heating, ventilating and air conditioning systems

    International Nuclear Information System (INIS)

    As part of a continuing radon in schools technology development effort, EPA's School Evaluation Team has performed radon mitigation in schools by the method of ventilation/pressurisation control technology. Ventilation rates were increased, at a minimum, to meet the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) standard, Ventilation for Acceptable Indoor Air Quality (ASHRAE 62-1989). This paper presents the results and the preliminary evaluations which led to the team's decision to implement this technology. Factors considered include energy penalties, comfort, indoor air quality (IAQ), building shell tightness, and equipment costs. Cost benefit of heat recovery ventilation was also considered. Earlier results of the SEP team's efforts have indicated a severe ventilation problem within the schools of the United States. Two case studies are presented where HVAC technology was implemented for controlling radon concentrations. One involved the installation of a heat recovery ventilator to depressurise a crawl space and provide ventilation to the classrooms which previously had no mechanical ventilation. The other involved the restoration of a variable air volume system in a two-storey building. The HVAC system's controls were restored and modified to provide a constant building pressure differential to control the entry of radon. Pre-mitigation and post-mitigation indoor air pollutant measurements were taken, including radon, carbon dioxide (CO2), particulates, and bio-aerosols. Long-term monitoring of radon, CO2, building pressure differentials, and indoor/outdoor temperature and relative humidity is presented. (author)

  2. A combined air cycle used for IC engine supercharging based on waste heat recovery

    International Nuclear Information System (INIS)

    Highlights: • A combined air cycle is proposed for IC engine supercharging based on WHR. • Cycle efficiency and energy recovery efficiency depend largely on working pressure. • Exhaust gas pressure of IC engine with combined air cycle is reduced largely. • IC engine fuel efficiency can be increased by 4.1% points at most. - Abstract: A combined air cycle is designed for internal combustion (IC) engine supercharging, which consists of IC engine working cycle and bottom cycle of waste heat recovery (WHR). The bottom cycle uses IC engine exhaust gas as cycle heat source, and its output power is used to drive the gas compressor. Both the heat transfer and thermodynamic processes of combined air cycle were investigated by numerical calculation under various cycle parameters and IC engine operating conditions. On this basis, the performances of combined air cycle and the improvement to IC engine performances were analyzed. Results show that, the cycle efficiency and exhaust gas energy recovery efficiency depend largely on the working pressure, and their maximum values appear at the working pressure of 0.35 MPa and 0.2 MPa, respectively. Compared with the naturally aspirated (NA) engine and turbocharging engine, this approach can make the fuel utilization efficiency of IC engine increase by 8.9% points and 4.1% points at most, respectively, due to the reduction of exhaust gas pressure. All these demonstrate that the proposed concept is a potentially useful approach for IC engine energy saving

  3. Hydrothermal treatment of sorption materials. Implications on adsorption heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Henninger, S.K.; Mueller, S.; Ratzsch, K.F.; Schossig, P.; Henning, H.M. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany). Dept. of Thermal Systems and Buildings; Munz, G. [PSE AG, Freiburg (Germany)

    2010-07-01

    Material stability of adsorbents for thermally driven systems like heat storage and heat transformation plays a key role. In particular high power-density applications like adsorption heat pumps and chillers in combination with recently developed adsorption materials lead to a significant increased number of cycles over the lifetime (<100'000) making cycle stability crucial. With regard to current developments on composite structures improving the heat and mass transfer, additional stability analysis like thermo-mechanical properties are now getting into focus. This contribution gives a broad overview on the stability of current available sorption materials like silica gels and zeolites, recently developed (silica-) aluminophosphates (AIPO/SAPO) and most novel synthesized metal organic framework (MOF) materials under hydrothermal treatment. The results give a first indication on the suitability of these materials for the use in heat storage, thermally driven sorption heat pumps and cooling machines. Pure powders as well as composites have been analysed under continuous cycling conditions. Whereas the stability of powders and granules have been analysed in-situ by thermogravimetric cycle measurements, a cycling-test rig has been developed in order to realise a lifetime stress of composites consisting of active sorption material and a support structure. The need for a first stage short-cycle analysis is demonstrated impressively by the dramatic loss of more than 50% in sorption capacity of a SAPO-34 sample within the first 10 cycles. Several composite samples have passed a treatment of 30'000 cycles or more and show continuous degradation effects leading to a reduction in sorption capacity of 20% compared to the initial value. (orig.)

  4. Heat transition during magnetic heating treatment: Study with tissue models and simulation

    International Nuclear Information System (INIS)

    The magnetic heating treatment (MHT) is well known as a promising therapy for cancer diseases. Depending on concentration and specific heating power of the magnetic material as well as on parameters of the magnetic field, temperatures between 43 and 55 °C can be reached. This paper deals with the evaluation of heat distribution around such a heat source in a tissue model, thereby focusing on the heat transfer from tissue enriched with magnetic nanoparticles to regions of no or little enrichment of magnetic nanoparticles. We examined the temperature distribution with several tissue phantoms made of polyurethane (PUR) with similar thermal conductivity coefficient as biological tissue. These phantoms are composed of a cylinder with one sphere embedded, enriched with magnetic fluid. Thereby the spheres have different diameters in order to study the influence of the surface-to-volume ratio. The phantoms were exposed to an alternating magnetic field. The magnetically induced heat increase within the phantoms was measured with thermocouples. Those were placed at defined positions inside the phantoms. Based on the measured results a 3-dimensional simulation of each phantom was built. We achieved an agreement between the measured and simulated temperatures for all phantoms produced in this experimental study. The established experiment theoretically allows a prediction of temperature profiles in tumors and the surrounding tissue for the potential cancer treatment and therefore an optimization of e.g. the respective magnetic nanoparticles concentrations for the desirable rise of temperature. - Highlights: • Four phantoms built to measure the temperature distribution during magnetic heating. • Simulations have been carried out based on experimental data. • Measured and simulated temperature distribution for different magnetic field strength. • Temperature profiles for with ferrofluid enriched areas of different size. • Comparison of experimental and simulated data

  5. Heat transition during magnetic heating treatment: Study with tissue models and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Henrich, Franziska [Technische Universität Dresden, Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, 01062 Dresden (Germany); Max Planck Institute for Polymer Research, Physics at Interfaces, 55128 Mainz (Germany); Rahn, Helene, E-mail: helene.rahn@tu-dresden.de [Technische Universität Dresden, Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, 01062 Dresden (Germany); Odenbach, Stefan [Technische Universität Dresden, Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, 01062 Dresden (Germany)

    2015-04-15

    The magnetic heating treatment (MHT) is well known as a promising therapy for cancer diseases. Depending on concentration and specific heating power of the magnetic material as well as on parameters of the magnetic field, temperatures between 43 and 55 °C can be reached. This paper deals with the evaluation of heat distribution around such a heat source in a tissue model, thereby focusing on the heat transfer from tissue enriched with magnetic nanoparticles to regions of no or little enrichment of magnetic nanoparticles. We examined the temperature distribution with several tissue phantoms made of polyurethane (PUR) with similar thermal conductivity coefficient as biological tissue. These phantoms are composed of a cylinder with one sphere embedded, enriched with magnetic fluid. Thereby the spheres have different diameters in order to study the influence of the surface-to-volume ratio. The phantoms were exposed to an alternating magnetic field. The magnetically induced heat increase within the phantoms was measured with thermocouples. Those were placed at defined positions inside the phantoms. Based on the measured results a 3-dimensional simulation of each phantom was built. We achieved an agreement between the measured and simulated temperatures for all phantoms produced in this experimental study. The established experiment theoretically allows a prediction of temperature profiles in tumors and the surrounding tissue for the potential cancer treatment and therefore an optimization of e.g. the respective magnetic nanoparticles concentrations for the desirable rise of temperature. - Highlights: • Four phantoms built to measure the temperature distribution during magnetic heating. • Simulations have been carried out based on experimental data. • Measured and simulated temperature distribution for different magnetic field strength. • Temperature profiles for with ferrofluid enriched areas of different size. • Comparison of experimental and simulated data.

  6. Effect of cyclic heat treatment on the microstructure and mechanical properties of CLF-1 steel

    International Nuclear Information System (INIS)

    Full text of publication follows: The two major blanket concepts for ITER TBM addressed by China are helium cooled lithium lead (HCLL) and helium cooled pebble bed (HCPB). Both concepts use reduced activation ferritic/martensitic (RAFM) steel as structural material. In Southwestern institute of physics (SWIP) of China, HCPB is the primary candidate blanket system and the RAFM steel of CLF-1 (Chinese low activation ferritic/martensitic steel) which is chosen as the primary candidate structural material is under research presently. In this paper, it is presented for the evolution of the microstructure, tensile and impact properties of RAFM steel CLF- 1 after cyclic heat treatment. The material investigated is a type of reduced activation ferritic/martensitic steel with higher tungsten and vanadium and lower manganese concentration compared with Eurofer97. The steel was supplied as bars in the normalized (1243 K/45 min/air-cooled) plus tempered (1006 K/90 min/air-cooled) condition. The cyclic heat treatment was performed at normalization temperature of 1243 K for 20 min then air cooled for 1, 2, 3, 4, and 5 times respectively. The effect of cyclic number on the microstructure and mechanical properties of CLF- 1 steel was observed and tested. The characterization of the microstructure was performed by means of optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. The results show that it is fully martensitic microstructure in all experimental conditions. The strength and ductility were improved and ductile-brittle transition temperature (DBTT) was decreased due to its finer grain size after cyclic heat treatment. (authors)

  7. Power generation from a new air-based Marnoch heat engine

    International Nuclear Information System (INIS)

    This paper examines the performance of a new Marnoch heat engine, which uses dry air and a pneumatic piston assembly to convert thermal energy to electricity. The system has unique capabilities of operating over temperature differentials less than 100 K. Unlike a common Stirling engine, the heat exchangers and piston assembly are not co-located, which is beneficial for positioning of heat exchangers in various configurations. This paper presents an operational laboratory-scale, proof-of-concept Marnoch heat engine (MHE), including its performance and power generation capabilities. It also presents a thermodynamic analysis of the system. Based on the MHE results, component modifications are made to improve its performance. The configuration has an efficiency of about thirty percent of a Carnot heat engine operating in the temperature range between 272 K and 372 K. Experimental data is acquired to provide verification of the predictive model, as well as demonstration of the MHE’s capabilities for efficient generation of electricity from waste heat sources. -- Highlights: ► This paper presents a thermodynamic analysis and experimental data for a Marnoch heat engine (MHE). ► The MHE has an efficiency of about thirty percent of a Carnot heat engine between 272 K and 372 K. ► Experimental data is successfully compared to the predictive model. ► The MHE shows promising performance for generation of electricity from waste heat sources.

  8. Opportunities for Saving Energy and Improving Air Quality in Urban Heat Islands

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem

    2007-07-01

    World energy use is the main contributor to atmospheric CO2. In 2002, about 7.0 giga metric tons of carbon (GtC) were emitted internationally by combustion of gas, liquid, and solid fuels (CDIAC, 2006), 2 to 5 times the amount contributed by deforestation (Brown et al., 1988). The share of atmospheric carbon emissions for the United States from fossil fuel combustion was 1.6 GtC. Increasing use of fossil fuel and deforestation together have raised atmospheric CO{sub 2} concentration some 25% over the last 150 years. According to global climate models and preliminary measurements, these changes in the composition of the atmosphere have already begun raising the Earth's average temperature. If current energy trends continue, these changes could drastically alter the Earth's temperature, with unknown but potentially catastrophic physical and political consequences. During the last three decades, increased energy awareness has led to conservation efforts and leveling of energy consumption in the industrialized countries. An important byproduct of this reduced energy use is the lowering of CO{sub 2} emissions. Of all electricity generated in the United States, about one-sixth is used to air-condition buildings. The air-conditioning use is about 400 tera-watt-hours (TWh), equivalent to about 80 million metric tons of carbon (MtC) emissions, and translating to about $40 billion (B) per year. Of this $40 B/year, about half is used in cities that have pronounced 'heat islands'. The contribution of the urban heat island to the air-conditioning demand has increased over the last 40 years and it is currently at about 10%. Metropolitan areas in the United States (e.g., Los Angeles, Phoenix, Houston, Atlanta, and New York City) have typically pronounced heat islands that warrant special attention by anyone concerned with broad-scale energy efficiency (HIG, 2006). The ambient air is primarily heated through three processes: direct absorption of solar radiation

  9. Ventilation System Type and the Resulting Classroom Temperature and Air Quality During Heating Season

    DEFF Research Database (Denmark)

    Gao, Jie; Wargocki, Pawel; Wang, Yi

    2014-01-01

    The present study investigated how different ventilation system types influence classroom temperature and air quality. Five classrooms were selected in the same school. They were ventilated by manually operable windows, manually operable windows with exhaust fan, automatically operable windows wi...... operable windows. Classrooms with automatically operable windows and exhaust fan and with mechanical ventilation systems achieved the best thermal environment and air quality during heating season among all classrooms examined.......The present study investigated how different ventilation system types influence classroom temperature and air quality. Five classrooms were selected in the same school. They were ventilated by manually operable windows, manually operable windows with exhaust fan, automatically operable windows with...... and without exhaust fan and by mechanical ventilation system. Temperature, relative humidity, carbon dioxide (CO2) concentration and opening of windows were continuously monitored for one month during heating season in 2012. Classroom with manually operable windows had the highest carbon dioxide...

  10. SIMULATION OF LARGE TURBINE ROTOR'S HEAT TREATMENT PROCESS

    Institute of Scientific and Technical Information of China (English)

    C. Jiang; Y.B. Chen; B.S. Wu; Q.L. Jin

    2005-01-01

    Temperature field numerical simulation about he heat treatment process curve of large turbine rotor is presented. With simulation software Deform3D in according to the heat treatment processing of China First Heavy Machinery, the details of temperature change at the different location of the rotor is to be found. Once knowing the temperature field change, the duplex grain defect long time existed in large forgings can be solved with a quantitative analysis instead of only the qualitative one. Precondition for small metal samples is brought to simulate microstructure and grain size change of large rotor according to the numerical simulation result. Also, consistent feature with real manufacture is showed from the physical experiment, so that the simulation can be used to not only improve the products process but also prevent wasting unnecessary energy and shorten process periods. The rotor quality is controlled thoroughly with plenty of experiments data.

  11. Effect of heat treatment on bioactivity of anodic titania films

    International Nuclear Information System (INIS)

    Anodic oxidation could be employed to produce crystalline titania films on Ti6Al4 V surfaces for inducing apatite formation in simulated body fluid (SBF). In this work, the effect of further heat treatment on the bioactivity of anodic titania films was researched. The surface constitution, morphology, crystal structure and apatite-forming ability of titania films were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicated the apatite formation on the Ti6Al4 V surfaces could be attributed to abundance of Ti-OH groups formed via anodic oxidation, but subsequent heat treatment would decrease the amount of surface hydroxyl (OH) groups and result in the loss of the apatite-forming ability.

  12. Microstructural evolvement of wrought magnesium alloy sheet during heat treatment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Magnesium alloy is the lightest structural metal material. As its ductility is usually limited because of its hexagonal closest packing (hcp) structure, it is significant to improve its forming performance. The primary way to achieve this goal is by grain refinement. This study explores new ways of grain refinement for cold-rolled sheet of magnesium alloy AZ31B by probing into its structural evolvement in heat treatment. It is found that recrystallization mostly takes place in the cold-rolled sheet in heattreatment, and refined and equiaxial recrystallization grains with an average diameter of (14 to 15) μm can be obtained by heattreatment at 260 °C for (60 to 90) min, which is an effective method to obtain refined symmetrical grains of magnesium alloy by heat treatment at a lower recrystallization temperature after cold-rolling.

  13. Heat treatment of heavy section low alloy steel plates

    International Nuclear Information System (INIS)

    Heavy section low alloy steel plates are used for nuclear reactor and direct oil desulfurizing reactor pressure vessels, etc. High integrity is, therefore, required of these steel plates. The factors which affect the internal soundness and notch toughness of heavy section low alloy steel plates are discussed in relation to heat treatment after rolling. Precipitation behavior of aluminum nitride in A533B steel plates during heat treatment after rolling is described with respect to the austenite grain size and notch toughness of the plate after final rolling. Cooling down to 4000C before normalizing is recommended to obtain good notch toughness. Selection of temperature and time for dehydrogenation at the ferrite region is discussed and it is shown that the optimum temperature for dehydrogenation must be determined by taking microsegregation in the plate into consideration. (author)

  14. Progress of heat-hazard treatment in deep mines

    Institute of Scientific and Technical Information of China (English)

    Yang Xiaojie; Han Qiaoyun; Pang Jiewen; Shi Xiaowei; Hou Dinggui; Liu Chao

    2011-01-01

    Based on the urgency of thermal hazard control in deep coal mines, we studied the status of deep thermal damage and cooling technology both at home and abroad, summarized the causes of deep thermal hazard, analysed and compared the control technologies for deep thermal hazards. The results show that the causes of deep thermal damage can be attributed to three aspects, i.e., climate, geological and mining factors, of which the geological factors are deemed the major reasons for thermal hazards. As well, we compared a number of cooling technologies of domestic and overseas provenance, such as central air conditioning cooling technology, ice cooling technology and water cooling technology, with one other cooling technology, i.e., the HEMS cooling technology, which has a large and important effect with its unique "pure air" cooling technology, realizes the utilizing of heat resources from underground to the ground. This technology makes use of heat obtained underground; thus the technology can promote low-carbon environmental economic development in coal mines, in order to achieve lowcarbon coal production in China.

  15. Satellite air temperature estimation for monitoring the canopy layer heat island of Milan

    DEFF Research Database (Denmark)

    Pichierri, Manuele; Bonafoni, Stefania; Biondi, Riccardo

    2012-01-01

    In this work, satellite maps of the urban heat island of Milan are produced using satellite-based infrared sensor data. For this aim, we developed suitable algorithms employing satellite brightness temperatures for the direct air temperature estimation 2 m above the surface (canopy layer), showing...... accuracies below 2K. The air temperatures measured by ground-based weather stations were properly matched with brightness temperatures observed by the Moderate-resolution Imaging Spectroradiometer (MODIS) on board of both Terra and Aqua satellites. In total, 931 daytime and nighttime scenes taken between...... 2007 and 2010 were processed. Analysis of the canopy layer heat island (CLHI) maps during summer months reveals an average heat island effect of 3–4K during nighttime (with some peaks around 5K) and a weak CLHI intensity during daytime. In addition, the satellite maps reveal a well defined island shape...

  16. Comparison of the externally heated air valve engine and the helium Stirling engine

    International Nuclear Information System (INIS)

    Highlights: • Air EHVE produces comparable power as equivalent helium Stirling engine. • No heat regenerator used in the EHVE, standard lubrication system. • External combustion engine combined with forced flow added (super-charging). • EHVE uses typical piston engine body design and governing cam system. • Possible use of different fuels: oil, coal, gas also sun and nuclear energy. - Abstract: A two-stroke, externally heated valve engine (EHVE) with a heater, a cooler and two blowers is simulated. The engine is entirely different from a typical Stirling engine. The pressure ratio pmax/pmin of its cycle is higher, but the engine volume and the mean value of the heat exchanger wall temperatures are the same. The power and efficiency of the EHVE and Stirling engines under the same maximum pressures are compared. The results show that the EHVE engine reaches almost the same level of performance as the Stirling engine, while using only available atmospheric air, rather than helium

  17. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    the outlet temperature of the gas cooler, the evaporation temperature and the efficiency of the compressor. General correlations for this optimal heat rejection pressure were derived based on cycle simulations. The correlations presented in this paper provide a basis for designing transcritical carbon...

  18. Computer programme for prediction steel parameters after heat treatment

    OpenAIRE

    J. Trzaska; L.A Dobrzanski; A. Jagiełło

    2007-01-01

    Purpose: The purpose of this paper is presentation of the computer program for calculating the Continuous Cooling Transformation diagrams for constructional and engineering steels.Design/methodology/approach: The computer program uses the artificial neural networks for prediction steel properties after heat treatment. Input data are chemical composition and austenitizing temperature. Results of calculation consist of temperature of the beginning and the end of transformation...

  19. Deep heat muscle treatment: A mathematical model - II

    International Nuclear Information System (INIS)

    In this paper the effect of viscosity variation on the flow of blood during deep heat muscle treatment is studied. Two methods; an asymptotic series expansion technique and a perturbation technique are employed to obtain the temperature distribution. The results are compared with the problem of Part I. A novel development in this part of the study is the combined asymptotic patching and matching technique. (author). 7 refs, 4 figs

  20. Computer simulation of microstructure transformation in heat treatment processes

    Directory of Open Access Journals (Sweden)

    B. Smoljan

    2007-09-01

    Full Text Available Purpose: Most often used methods for prediction of austenite decomposition are described and analysed.Design/methodology/approach: The austenite decomposition prediction is usually based on continuous cooling transformation (CCT diagrams. The next method is based on semi-empirical approach based on the Scheil’s additivity rule. The third method is based on time, t8/5, relevant for microstructure transformation measured on Jominy-specimen. Very good results are obtained by artificial neural network (ANN with learning rule based on the error backpropagation algorithm.Findings: By the comparison of application ability of investigated methods in mathematical modelling and computer simulation of austenite decomposition during the cooling of low-alloyed steel, it can be concluded that everyone method gives different results, and minimum variation in elemental composition and history of cooling may produce extremely different results in microstructure portion. Very good results were achieved by the method, which applies the Jominy-test results. In this method the additivity rule and specific performance of Jominy-test has been combined.Research limitations/implications: The investigation was performed on low-alloyed steels.Practical implications: The results of prediction of microstructure transformations could be used for prediction of mechanical properties after a heat treatment and of generation of stresses and strains during a heat treatment.Originality/value: The ability and applicability of potential methods of austenite decomposition prediction in general mathematical modelling of heat treatment of steel are carried out. The finding of this paper will be so useful in development new algorithms in mathematical modelling and computer simulation of heat treatment of low-alloyed steels.

  1. Multiple model approach and experimental validation of a residential air-to-air heat pump

    OpenAIRE

    Garde, Francois; Garde, François; Boyer, Harry; Pignolet, Florence; Lucas, Franck; Brau, Jean

    1997-01-01

    International audience The beginning of this work is the achievement of a design tool, which is a multiple model software called " CODYRUN ", suitable for professionnals and usable by researchers. The original aspect of this software is that the designer has at his disposal a wide panel of choices between different heat transfer models More precisely, it consists in a multizone software integrating both natural ventilation and moisture tranfers . This software is developed on PC micro comp...

  2. Corrosion resistance of structural material AlMg-2 in water following heat treatment and cooling

    International Nuclear Information System (INIS)

    Corrosion tests of structural material AlMg-2 in water were carried out using autoclave in order to study the effects of heat treatment on the corrosion resistance of the material. Prior to the tests, the samples were heat-treated at temperatures of 90, 200, 300 and 500 °C and cooled in air, sand and water. The corrosion tests were conducted in water at temperature of 150 °C for 250 hours. The results showed that AlMg-2 samples were corroded although the increase of mass gain was relatively small. Heat treatment from 90 to 500 °C in sand cooling media resulted in an increase of mass gain despite that at 300 °C the increase was less than those at 200 °C and 500 °C. For water cooling media in the temperature range of 90 to 200 °C, the mass gain increased from 0.1854 g/cm2 to 2.1204 g/cm2 although after 200 °C it decreased to 1.8207 g/cm2 and 1.6779 g/cm2 respectively. For air cooling media, the mass gain was relatively constant. Based on the experiment results, it can be concluded that heat treatment and cooling did not significantly influence the corrosion resistance of material AlMg-2. The passive film Al2O3 on the surface was able to protect the inner surface from further corrosion. Water media with pH range from 4 – 9 did not cause damage to passive layer formed. (author)

  3. PERFORMANCE EVALUATION AND EMISSION CHARACTERISTICS OF LOW HEAT REJECTION ENGINE USING AIR GAP INSULATION

    Directory of Open Access Journals (Sweden)

    M. IRSHAD AHMED

    2013-06-01

    Full Text Available It is well known fact that about 30% of the energy supplied is lost through the coolant and the 30% is wasted through friction and other losses, thus leaving only about 30% of energy utilization for useful purposes. In view of the above, the major thrust in engine research during the last two decades has been on the development of low heat rejection engines. The Low Heat Rejection (LHR engine has been given considerable attention recently as engine builders struggle to find remaining avenues to improve economy and lower emissions. The concept of air gap insulated piston has been explored by providing 1mm air gap within the piston by using bolted type piston. The bolted air gapinsulated piston provides complete sealing of air gap necessary for continued insulation. The design evolved provides high insulation combining adequate durability. In order to provide high insulation andreliability, proper designing of the air gap piston has to be ensured. The piston with 1mm thickness of air gap are designed with two different material. The insulation provides betterment in fuelconsumption at normal operating condition than a conventional piston engine and also the delay period tends to reduce the emissions levels of Hydrocarbons and carbon monoxide. The combustion rate is increased because of insulation and hence there is reduced vibration and noise level.

  4. Treatment of air dried archaeological wool textiles from waterlogged environment

    DEFF Research Database (Denmark)

    Scharff, Annemette Bruselius

    2014-01-01

    Air-dried, wet archaeological wool textiles can be flat and stiff with brittle fibers, but is this a permanent collapse or can they regain their size in water? Iron Age textiles were tested comparing the width of dry fibers with the width of fibers treated in water or 70% ethanol. Both liquids...... expanded the fibers and the yarn increased in size, resulting in more flexible and less brittle textiles. This property was kept when the textiles were dried by stepwise dehydration in ethanol, acetone, and white spirit with a final treatment in 5% lanolin. Preliminary tests on brittle textiles can be...

  5. Demonstration of the Performance of an Air-Type Photovoltaic Thermal (PVT System Coupled with a Heat-Recovery Ventilator

    Directory of Open Access Journals (Sweden)

    Jin-Hee Kim

    2016-09-01

    Full Text Available A heat-recovery ventilator (HRV effectively conducts ventilation by recovering waste heat from indoors to outdoors during heating periods. However, dew condensation associated with the HRV system may arise due to the difference between the indoor temperature and the very low outdoor temperature in winter, and this can decrease the heat exchange efficiency. These problems can be solved by the pre-heating of the incoming air, but additional energy is required when pursuing such a strategy. On the other hand, an air-type photovoltaic thermal (PVT system produces electricity and thermal energy simultaneously using air as the heat transfer medium. Moreover, the heated air from the air-type PVT system can be connected to the HRV to pre-heat the supply air instead of taking in the cold outdoor air. Thus, the ventilation efficiency can be improved and the problems arising during the heating period can be resolved. Consequentially, the heating energy required in a building can be reduced, with additional electricity acquired as well. In this paper, the performance of an air-type PVT system coupled with an HRV is assessed. To do this, air-type PVT collectors operating at 1 kWp were installed in an experimental house and coupled to an HRV system. Thermal performance and heating energy required during the winter season were analyzed experimentally. Furthermore, the electrical performances of the air-type PVT system with and without ventilation at the back side of the PV during the summer season were analyzed.

  6. Robustness analysis of an air heating plant and control law by using polynomial chaos

    International Nuclear Information System (INIS)

    This paper presents a robustness analysis of an air heating plant with a multivariable closed-loop control law by using the polynomial chaos methodology (MPC). The plant consists of a PVC tube with a fan in the air input (that forces the air through the tube) and a mass flux sensor in the output. A heating resistance warms the air as it flows inside the tube, and a thermo-couple sensor measures the air temperature. The plant has thus two inputs (the fan's rotation intensity and heat generated by the resistance, both measured in percent of the maximum value) and two outputs (air temperature and air mass flux, also in percent of the maximal value). The mathematical model is obtained by System Identification techniques. The mass flux sensor, which is nonlinear, is linearized and the delays in the transfer functions are properly approximated by non-minimum phase transfer functions. The resulting model is transformed to a state-space model, which is used for control design purposes. The multivariable robust control design techniques used is the LQG/LTR, and the controllers are validated in simulation software and in the real plant. Finally, the MPC is applied by considering some of the system's parameters as random variables (one at a time, and the system's stochastic differential equations are solved by expanding the solution (a stochastic process) in an orthogonal basis of polynomial functions of the basic random variables. This method transforms the stochastic equations in a set of deterministic differential equations, which can be solved by traditional numerical methods (That is the MPC). Statistical data for the system (like expected values and variances) are then calculated. The effects of randomness in the parameters are evaluated in the open-loop and closed-loop pole's positions

  7. Self-optimizing control of air-source heat pump with multivariable extremum seeking

    International Nuclear Information System (INIS)

    The air-source heat pump (ASHP) is widely adopted for cooling and heating of residential and commercial buildings. The performance of ASHP can be controlled by several operating variables, such as compressor capacity, condenser fan speed, evaporator fan speed and suction superheat. In practice, the system characteristics can be varied significantly by the variations in ambient condition, operation setpoint, internal thermal load and equipment degradation, which makes it difficult to obtain accurate plant models. As consequence, the model based control strategies for ASHP could limit the achievable energy efficiency. Model-free self-optimizing control strategies are thus more preferable. In this study, a multi-input extremum seeking control (ESC) scheme is proposed for both heating and cooling operation of ASHP. The zone temperature is assumed to be regulated by the compressor capacity, while the expansion valve opening is used to regulate the suction superheat at the given setpoint. The total power consumption of the compressor, the condenser fan and the evaporator fan is measured as input to the ESC, while the ESC controls the evaporator fan speed, the condenser fan speed and the suction superheat setpoint. The proposed scheme is evaluated with a Modelica based dynamic simulation model of ASHP under both cooling and heating modes of operation. Simulation results show the effectiveness of the proposed scheme to achieve the maximum achievable efficiency in a nearly model-free manner. - Highlights: • Multi-input ESC. • Air-source heat pump. • Cooling and heating. • Modelica based model

  8. Performance enhancement of an experimental air conditioning system by using TiO2/methanol nanofluid in heat pipe heat exchangers

    Science.gov (United States)

    Monirimanesh, Negin; Nowee, S. Mostafa; Khayyami, Shideh; Abrishamchi, Iman

    2016-05-01

    The effect of using nanofluid in thermosyphon-type heat pipe heat exchangers on energy conservation of an air-conditioning system was sought in this study. Innovatively, two heat exchangers in-series were deployed using TiO2/methanol nanofluids with 0-4 wt% concentrations as working fluids. The impacts of temperature and relative humidity on the effectiveness of 2 and 4-row heat exchangers were analyzed experimentally and more that 40 % energy saving was obtained.

  9. Evaluation of carbon diffusion in heat treatment of H13 tool steel under different atmospheric conditions

    Directory of Open Access Journals (Sweden)

    Maziar Ramezani

    2015-04-01

    Full Text Available Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of heat treatment experiments had been conducted under different atmospheric conditions and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat treatment without atmospheric control, heat treatment with stainless steel foil wrapping, pack carburization heat treatment and vacuum heat treatment. The results showed that stainless steel foil wrapping could restrict decarburization process, resulting in a constant hardness profile as vacuum heat treatment does. However, the tempering characteristic between these two heat treatment methods is different. Results from the gas nitrided samples showed that the thickness and the hardness of the nitrided layer is independent of the carbon content in H13 steel.

  10. Performance Comparison of Hydronic Secondary Loop Heat Pump and Conventional Air-Source Heat Pump

    OpenAIRE

    Bell, Ian; Braun, James

    2012-01-01

    In residential heat pump systems, the motivation for secondary loop systems is to allow for the use of flammable or toxic refrigerants with lower global warming potentials than the currently employed HFC refrigerants. The addition of radiant panels as integral building components (embedded in concrete at construction or attached to the underside of wood flooring) is becoming more common. Combining the large surface area of the radiant panel and an efficient primary loop, a hydronic secondary ...

  11. Air radon concentration decrease in a waste water treatment plant

    International Nuclear Information System (INIS)

    222Rn is a naturally occurring gas created from the decay of 226Ra. The long-term health risk of breathing radon is lung cancer. One particular place where indoor radon concentrations can exceed national guidelines is in wastewater treatment plants (WWTPs) where treatment processes may contribute to ambient airborne concentrations. The aim of this paper was to study the radon concentration decrease after the application of corrective measures in a Spanish WWTP. According to first measures, air radon concentration exceeded International Commission Radiological Protection (ICRP) normative (recommends intervention between 400 and 1000 Bq m-3). Therefore, the WWTP improved mechanical forced ventilation to lower occupational exposure. This measure allowed to increase the administrative controls, since the limitation of workers access to the plant changed from 2hd-1 (considering a maximum permissible dose of 20 mSv y-1 averaged over 5 y) to 7 h d-1 (authors)

  12. 零气耗余热再生空气干燥器应用%Application of Zero Air Consumption Waste Heat Regenerating Air Dryer

    Institute of Scientific and Technical Information of China (English)

    凌晨; 陈恩军; 吴冰; 赵刘强

    2016-01-01

    介绍了零气耗余热再生空气干燥器原理、特点及应用条件,并针对首钢京唐公司压缩空气系统现有问题提出了解决方案.通过在现有高气耗空压机系统中应用零气耗余热再生空气干燥器,既节约了再生耗气量,又节省了电力能源的消耗.%The principle, characteristics and application condition of zero air consump-tion waste heat regenerating air dryer are introduced and solutions for existing problems in the compressed air system of Shougang Jingtang Steel are provided. Using zero air consumption waste heat regenerating air dryer in existing high air consumption compressor system can not only reduce regeneration air consumption but also save electricity.

  13. Investigation of heat distribution during magnetic heating treatment using a polyurethane-ferrofluid phantom-model

    Science.gov (United States)

    Henrich, F.; Rahn, H.; Odenbach, S.

    2014-02-01

    Magnetic heating treatment can be used as an adjuvant treatment for cancer therapy. In this therapy, magnetic nanoparticles are enriched inside the tumour and exposed to an alternating magnetic field. Due to magnetic losses the temperature in the tumour rises. The resulting temperature profile inside the tumour is useful for the therapeutic success. In this context heat transfer between tissue with nanoparticles and tissue without nanoparticles is a highly important feature which is actually not understood in detail. In order to investigate this, a phantom has been created which can be used to measure the temperature profile around a region enriched with magnetic nanoparticles. This phantom is composed of a material, which has similar thermal conductivity as human tissue. A tempered water bath surrounds the phantom to establish a constant surrounding temperature simulating the heat sink provided by the human body in a real therapeutic application. It has been found that even at a low concentration of magnetic nanoparticles around 13 mg/ml, sufficient heating of the enriched region can be achieved. Moreover it has been observed that the temperature drops rapidly in the material surrounding the enriched region. Corresponding numerical investigations provide a basis for future recalculations of the temperature inside the tumour using temperature data obtained in the surrounding tissue.

  14. User's manual for steady-state computer simulation for air-to-air heat pumps with selected examples

    Energy Technology Data Exchange (ETDEWEB)

    1982-06-30

    A steady-state computer simulation model has been developed for conventional, vapor compression cycle, electrically driven air-to-air heat pumps. Comparison between the heat pump simulation model predictions and available data from three heat pump experiments indicate that the predictions generally are within accepted tolerances. A sensitivity analysis was made to assess the effect of possible variations in some of the input parameters on the system's thermal performance. The computer simulation model is briefly described for heating and cooling modes, and simulation model input data and output are given. (LEW)

  15. Effectiveness and humidification capacity investigation of liquid-to-air membrane energy exchanger under low heat capacity ratios at winter air conditions

    Science.gov (United States)

    Kassai, Miklos

    2015-06-01

    In this research, a novel small-scale single-panel liquid-to-air membrane energy exchanger has been used to numerically investigate the effect of given number of heat transfer units (4.5), different cold inlet air temperature (1.7, 5.0, 10.0 °C) and different low heat capacity ratio (0.4, 0.5, 0.6, 0.7, 0.8, 0.9) on the steady-state performance of the energy exchanger. This small-scale energy exchanger represents the full-scale prototypes well, saving manufacturing costs and time. Lithium chloride is used as a salt solution in the system and the steady-state total effectiveness of the exchanger is evaluated for winter inlet air conditions. The results show that total effectiveness of the energy exchanger decreases with heat capacity ratio in the mentioned range. Maximum numerical total effectiveness of 97% is achieved for the energy exchanger. Increasing the heat capacity ratio values on given inlet air temperature, the humidification capacity of energy exhanger is also investigated in this paper. The humidification performance increases with heat capacity ratio. The highest humidification performance (4.53 g/kg) can be reached when inlet air temperature is 1.7 °C, and heat capacity ratio is 1.0 in winter inlet air conditions in the range of low heat capacity ratio.

  16. An experimental study on defrosting heat supplies and energy consumptions during a reverse cycle defrost operation for an air source heat pump

    International Nuclear Information System (INIS)

    For a space heating air source heat pump (ASHP) unit, when its outdoor coil surface temperature is below both the air dew point temperature and the freezing point of water, frost will form on its outdoor coil surface. Frosting affects its operational performance and energy efficiency. Therefore, periodic defrosting is necessary. Currently, the most widely used standard defrosting method for ASHP units is reverse cycle defrost. The energy that should have been used for space heating is used to melt frost, vaporize the melted frost off outdoor coil surface and heat ambient air during defrosting. It is therefore necessary to study the sources of heat supplies and the end-uses of the heat supplied during a reverse cycle defrost operation. In this paper, firstly, an experimental setup is described and experimental procedures are detailed. This is followed by reporting the experimental results and the evaluation of defrosting efficiency for the experimental ASHP unit. Finally, an evaluation of defrosting heat supplies and energy consumptions during a revere cycle defrost operation for the experimental ASHP unit is presented. The experimental and evaluation results indicated that the heat supply from indoor air contributed to 71.8% of the total heat supplied for defrosting and 59.4% of the supplied energy was used for melting frost. The maximum defrosting efficiency could be up to 60.1%. - Highlights: ► Heat supply and consumption during reverse cycle defrost was experimentally studied. ► Indoor air contributed to >70% of total heat supply when indoor fan was turned on. ► ∼60% of the supplied energy was used for melting frost. ► Alternate heat supply other than indoor air should be explored.

  17. Effects of heat treatment and hot deformation on the secondary α phase evolution of TC8 titanium alloy

    International Nuclear Information System (INIS)

    To investigate the effect of heat treatment and hot deformation on the secondary α phase evolution, the heat treatment and isothermal compression were carried out for the as-received TC8 titanium alloy respectively. An optical microscope (OM) and a scanning electron microscope (SEM) were used to examine the microstructure. In the heat treatment, the secondary α phase can precipitate only as the TC8 titanium alloy is heat treated at a heating temperature of 980 °C followed by air cooling. In the isothermal compression, the secondary α phase precipitates as an irregular morphology due to the high dislocation content in the deformed β phase at a low deformation temperature of 860 °C, while as a regular lamellar colony due to the high supersaturation in the deformed β phase at a high deformation temperature of 940 °C. Meanwhile, the height reduction has a significant effect on the content and morphology of secondary α phase in the isothermally compressed TC8 titanium alloy. Comparing the secondary α phase evolution in the isothermal compression with that in the heat treatment of TC8 titanium alloy, it can be concluded that the hot deformation has a promoting effect on the precipitation of secondary α phase due to the deformation heat, crystal defect and dynamic recrystallization of β phase generated in the isothermal compression of TC8 titanium alloy

  18. Effects of heat treatment and hot deformation on the secondary α phase evolution of TC8 titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K.; Li, M.Q., E-mail: honeymli@nwpu.edu.cn

    2014-09-08

    To investigate the effect of heat treatment and hot deformation on the secondary α phase evolution, the heat treatment and isothermal compression were carried out for the as-received TC8 titanium alloy respectively. An optical microscope (OM) and a scanning electron microscope (SEM) were used to examine the microstructure. In the heat treatment, the secondary α phase can precipitate only as the TC8 titanium alloy is heat treated at a heating temperature of 980 °C followed by air cooling. In the isothermal compression, the secondary α phase precipitates as an irregular morphology due to the high dislocation content in the deformed β phase at a low deformation temperature of 860 °C, while as a regular lamellar colony due to the high supersaturation in the deformed β phase at a high deformation temperature of 940 °C. Meanwhile, the height reduction has a significant effect on the content and morphology of secondary α phase in the isothermally compressed TC8 titanium alloy. Comparing the secondary α phase evolution in the isothermal compression with that in the heat treatment of TC8 titanium alloy, it can be concluded that the hot deformation has a promoting effect on the precipitation of secondary α phase due to the deformation heat, crystal defect and dynamic recrystallization of β phase generated in the isothermal compression of TC8 titanium alloy.

  19. Field Measurements of Heating Efficiency of Electric Forced-Air Furnaces in Six Manufactured Homes.

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Bob; Palmiter, Larry S.; Siegel, Jeff

    1994-07-26

    This report presents the results of field measurements of heating efficiency for six manufactured homes in the Pacific Northwest heated with electric forced-air systems. This is the first in a series of regional and national efforts to measure in detail the heating efficiency of manufactured homes. Only six homes were included in this study because of budgetary constraints; therefore this is not a representative sample. These investigations do provide some useful information on the heating efficiency of these homes. Useful comparisons can be drawn between these study homes and site-built heating efficiencies measured with a similar protocol. The protocol used to test these homes is very similar to another Ecotope protocol used in the study conducted in 1992 and 1993 for the Bonneville Power Administration to test the heating efficiency of 24 homes. This protocol combined real-time power measurements of furnace energy usage with energy usage during co-heat periods. Accessory data such as house and duct tightness measurements and tracer gas measurements were used to describe these homes and their heating system efficiency. Ensuring that manufactured housing is constructed in an energy and resource efficient manner is of increasing concern to manufactured home builders and consumers. No comparable work has been done to measure the heating system efficiency of MCS manufactured homes, although some co-heat tests have been performed on manufactured homes heated with natural gas to validate HUD thermal standards. It is expected that later in 1994 more research of this kind will be conducted, and perhaps a less costly and less time-consuming method for testing efficiencies will be develops.

  20. Heat exchange at air-sea interface in the South China Sea during monsoon periods in 1986

    Institute of Scientific and Technical Information of China (English)

    WU Disheng; LU Boming; FENG Weizhong; XU Jianping; YAN Jinghua; ZHAO Xue; ZHOU Shuihua; ZHANG Jiwei; QIAO Guanyu; LIN Fu

    2006-01-01

    In order to explore the interaction between the sea and monsoon in the South China Sea, the heat exchanges at air-sea interface during monsoon periods in 1986 were calculated using observational data. It shows that when the summer monsoon bursts and prevails over the South China Sea, the air-sea interface heat exchange is strong and the latent heat rises rapidly in the intertropical convergence zone and the tropic cyclone system near 20.49°N, 114.14°E. On May 24, 1986, the sensible heat became positive in the typhoon system. The heating exchange indicates that heat is transported from ocean to atmosphere, with major contribution of latent heat. When the summer monsoon prevails over the South China Sea and the weather is fine, even SST (sea surface temperature) is high, but sensible heat appears to be negative. The heat exchange indicates that heat is transported from atmosphere to ocean, with major contribution of short-wave radiation absorbed by sea surface and sensible heat. When summer monsoon is over and the northeast monsoon prevails over the South China Sea, the heat exchange at air-sea interface is very strong. The heating exchange shows that the ocean heats the atmosphere, with major contribution of latent heat when cold air arrives at the sea surface and the sensible heat rises to positive rapidly. Therefore it can be concluded that the heat exchange at air-sea interface is different from the SST in South China Sea. When the summer monsoon prevails over the South China Sea, the main trend is the ocean responding to the atmosphere.

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

    International Nuclear Information System (INIS)

    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

  2. Meso-scale wrinkled coatings to improve heat transfers of surfaces facing ambient air

    International Nuclear Information System (INIS)

    Meso-scale (micrometer-to submillimeter-scale) wrinkled surfaces coated on steel sheets used in outdoor storage and transport facilities for industrial low-temperature liquids were discovered to efficiently increase convective heat transfer between ambient air and the surface. The radiative and convective heat transfer coefficients of various wrinkled surfaces, which were formed by coating steel sheets with several types of shrinkable paints, were examined. The convective heat transfer coefficient of a surface colder than ambient air monotonically changed with average height difference and interval distance of the wrinkle undulation, where the proportions were 0.0254 and 0.0054 W/m2/K/μm, respectively. With this wrinkled coating, users can lower the possibility of condensation and reduce rust and maintenance cost of facilities for industrial low-temperature liquids. From the point of view of manufacturers, this coating method can be easily adapted to conventional manufacturing processes. - Highlights: • Various wrinkled surfaces were fabricated by a practical process. • Topographical effect on convection was parameterized separately from radiation. • Meso-scale wrinkled coatings increased convective heat transfer with ambient air. • Maintenance cost of outdoor steel sheets due to condensation can be reduced

  3. Development of a Bench-Top Air-to-Water Heat Pump Experimental Apparatus

    Directory of Open Access Journals (Sweden)

    H. I. Abu-Mulaweh

    2009-09-01

    Full Text Available A bench-top air-to-water heat pump experimental apparatus was designed,developed, and constructed for instructional and demonstrative purposes. Thisair-to-water heat pump experimental apparatus is capable of demonstratingthermodynamics and heat transfer concepts and principles. This heat pumpexperimental setup was designed around the vapor compression refrigerationcycle. This experimental apparatus has an intuitive user interface, reliable, safefor student use, and portable. The interface is capable of allowing dataacquisition by a computer. A PC-based control system which consists ofLabVIEW and data acquisition unit is employed to monitor and control thisexperimental laboratory apparatus. This paper provides details about thedevelopment of this unit and the integration of the electrical/electronic componentand the control system.

  4. Convective heat transfer from rotating disks subjected to streams of air

    CERN Document Server

    aus der Wiesche, Stefan

    2016-01-01

    This Brief describes systematically results of research studies on a series of convective heat transfer phenomena from rotating disks in air crossflow. Phenomena described in this volume were investigated experimentally using an electrically heated disk placed in the test section of a wind tunnel. The authors describe findings in which transitions between different heat transfer regimes can occur in dependency on the involved Reynolds numbers and the angle of incidence, and that these transitions could be related to phenomenological Landau and Landau-de Gennes models. The concise volume closes a substantial gap in the scientific literature with respect to flow and heat transfer in rotating disk systems and provides a comprehensive presentation of new and recent results not previously published in book form.

  5. Air pollution prognosis during reorganization of Visaginas heating structure after closing the Ignalina Nuclear Power Plant

    International Nuclear Information System (INIS)

    Air pollution prognosis after reorganization of the Visaginas heating structure in the case of closing the Ignalina Nuclear Power Plant has been made. If heavy fuel, oil with 3% sulphur content, and indigenous incinerable waste would be used as fuel in the built boilers houses, the maximal permissible concentrations of sulphur dioxide and hydrogen chlorine in the smoke would be exceeded. During use of heavy fuel (oil with 1% sulphur content) without smoke desulphurization, the third variant of heat and steam surplus would be best from the ecological point of view. In this case the heat for Visaginas would be produced in the current reserve boiler house and the heat and steam for the closed INPP would be produced in the boiler house located in the INPP territory. The optimum height and diameter of chimneys for both boiler houses would be 90 and 4.2 m, respectively. (author)

  6. Downward flow of water with entrained air in a nonuniformaly heated subdivided annulus

    International Nuclear Information System (INIS)

    This paper describes an experimental study in which water was fed to a vertical annulus, entraining air in downward flow. The annulus was subdivided by longitudinal fins into four subchannels and was heated with an azimuthally varying heat flux. A bypass was provided to simulate flow in parallel channels. For steady liquid flow, inlet temperature, and pressure boundary conditions, the power was increased until critical heat flux was reached. Overheating characteristics were grouped according to the prevailing flow pattern. In annular flows (jL L L) overheating occurs by diverting inlet flow to the bypass and again involves the whole test section. Except at the very lowest flow rates, critical heat flux occurs when the effluent liquid temperature is below saturation

  7. Effect of heat treatment on precipitation on V-5Cr-5Ti heat BL63

    Energy Technology Data Exchange (ETDEWEB)

    Gelles, D.S.; Li, H. [Pacific Northwest National Laboratory, Richland, WA (United States)

    1996-04-01

    The microstructures of V-5Cr-5Ti heat BL63 are compared following heat treatments at 1125{degrees}C for 1 h and 1125{degrees}C for 1 h followed by 890{degrees}C for 24 h. Following the 890{degrees}C treatment, precipitate density was increased due to the presence of a moderate density of highly elongated particles. Microchemical analysis showed that these particles often contained both Ti and V, some particles showed minor amounts of Si, S, and P, but it was also possible to show that these precipitates were enriched in O rather than C or N. Following the 1125{degrees}C heat treatment, only Si was found as a minor impurity in large particles, but S could be identified at grain boundaries, which were coated with a fine distribution of precipitates. The embrittlement observed is ascribed to a combination of interstitial solid solution hardening and grain boundary embrittlement, with interstitial hardening likely the dominant factor.

  8. Sterilization of soybean powder with plasma treatment in atmospheric humid air

    Science.gov (United States)

    Iwami, R.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.; Nakayama, A.; Nakagawa, K.

    2013-10-01

    Sterilization of foods has been performed by conventional methods such as heat, steam and chemical solutions. However, these sterilization techniques could cause damages to the food material. It is considered that plasma sterilization at atmospheric pressure is one of the promising alternative methods because of the low temperature process. In our previous study, the inactivation of Bacillus atrophaeusspores by a dielectric barrier discharge (DBD) plasma produced in atmospheric humid air was investigated in order to develop low-temperature, low-cost and high-speed plasma sterilization technique. The results showed that the inactivation of Bacillus atrophaeusspores was found to be dependent strongly on the humidity. In the present study, the plasma treatment technique in humid air is applied to sterilization of soybean powder. Effects of plasma sterilization were successfully confirmed by a colony counting method. It was found that the sterilization efficiency was increased by using the humid air as the discharge gas. In the conference, an improvement of the plasma treatment system to enhance the sterilization efficiency will be shown.

  9. Effect of heat treatment on antimycotic activity of Sahara honey

    Directory of Open Access Journals (Sweden)

    Moussa Ahmed

    2014-11-01

    Full Text Available Objective: To evaluate the influence of the temperature on honey colour, polyphenol contents and antimycotic capacity and to evaluate the correlation between these parameters. Methods: Sahara honey were heated up to 25, 50, 75 and 100 °C for 15, 30 and 60 min, and their colour intensity, polyphenol contents and antimycotic capacity. The Folin-Ciocalteu test was used to determine the total polyphenol contents (TPC. The antimycotic activity was evaluated both by agar diffusion method and micro wells dilution method against the Candida albicans (C. albicans and Candida glabrata (C. glabrata. Results: Initial values for TPC in Sahara honey ranged from 0.55 to 1.14 mg of gallic acid per kg of honey, with the average value of 0.78 mg of gallic acid per kg of honey. The TPC values after heat-treatment were 0.54 to 1.54 with the average value of 1.49 mg. The minimal inhibitory concentrations before heat-treatment of Sahara honey against C. albicans and C. glabrata ranged from 3.06%-12.5% and 50% respectively. After heat-treatment the minimal inhibitory concentrations between 12.5% and 50% for C. albicans and C. glabrata, respectively. The diameters of inhibition zones of Sahara honey with 50% concentration varied from (12.67-15.00 mm by C. albicans to (14.33-15.67 mm by C. glabrata. The diameters of inhibition zones after heat-treatment at 25 and 50 °C for 15.30 and 60 min ranged from (2.00-18.67 mm by C. albicans to (8.00-16.67 mm by C. glabrata. Statistically significant relations between the TPC and the colour intensity of Sahara honey (r=0.99, P<0.05. Furthermore, the results showed that the TPC and colour is not correlated with the antimycotic capacity. Conclusions: To our knowledge this is the first report on the antimycotic capacity of Sahara honey.

  10. Heat transfer performance analysis of a multi channel volumetric air receiver for solar power tower

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Eui Guk [LG Electronics Inc., Daejeon (Korea, Republic of)

    2012-03-15

    In this study, a heat transfer performance analysis is carried out for a multi channel volumetric air receiver for a solar power tower. On the basis of a series of reviews regarding the relevant literature, a calculation process is proposed for the prediction of the wall and air temperature distributions of a single channel at given geometric and input conditions. Furthermore, a unique mathematical model of the receiver effectiveness is presented through analysis of the temperature profile. The receiver is made of silicon carbide. A total of 225 square straight channels per module are molded to induce the air flow, and each channel has the dimensions of 2mm(W)x2mm(H)x0.2mm(t)x320mm(L). The heat transfer rate, temperature distribution and effectiveness are presented according to the variation of the channel and module number under uniform irradiation and mass flow rate. The available air outlet temperature applied to the solar power tower should by over 700 .deg. C. This numerical model was actually used in the design of a 200kw level commercial solar air receiver, and the required number of modules satisfying the thermal performance could be obtained for the specified geometric and input conditions.

  11. Experiments on air bubbles injection into a vertical shell and coiled tube heat exchanger; exergy and NTU analysis

    International Nuclear Information System (INIS)

    Highlights: • Air bubbles injection was employed to enhance the performance of a vertical shell and coiled tube heat exchanger. • Air bubbles were injected into the shell side of heat exchanger via a new method at different conditions. • NTU enhancement and Exergy loss due to air bubbles injection were studied. • Present type of air bubble injection significantly increased the amount NTU and performance of heat exchanger. - Abstract: In this paper, attempts are made to increase the number of thermal units (NTU) and performance in a vertical shell and coiled tube heat exchanger via air bubble injection into the shell side of heat exchanger. Besides, exergy loss due to air bubble injection is investigated. Indeed, air bubble injection and bubbles mobility (because of buoyancy force) can intensify the NTU and exergy loss by mixing the thermal boundary layer and increasing the turbulence level of the fluid flow. Air bubbles were injected inside the heat exchanger via a special method and at new different conditions in this paper. It was demonstrated that the amount of NTU and effectiveness can be significantly improved due to air bubbles injection

  12. Temperature Evaluation of Heat Transferring Body while Preparing Temperature Chart of Heating Technologies and Metal Thermal Treatment

    Directory of Open Access Journals (Sweden)

    A. P. Nesenchuk

    2011-01-01

    Full Text Available The paper considers problems pertaining to temperature evaluation of a heat transferring body in the operational space of high temperature installations. A formula for evaluation of this temperature has been written down in the paper. Calculation of a heating transferring body (furnace makes it possible to realize temperature chart parameters in the plant heating technologies and steel thermal treatment.

  13. Temperature Evaluation of Heat Transferring Body while Preparing Temperature Chart of Heating Technologies and Metal Thermal Treatment

    OpenAIRE

    A. P. Nesenchuk; T. V. Ryzhova; O. F. Kraetskaya; S. S. Коvaliov; A. V. Begliak

    2014-01-01

    The paper considers problems pertaining to temperature evaluation of a heat transferring body in the operational space of high temperature installations. A formula for evaluation of this temperature has been written down in the paper. Calculation of a heating transferring body (furnace) makes it possible to realize temperature chart parameters in the plant heating technologies and steel thermal treatment.

  14. Energetic performances of an optimized passive Solar Heating Prototype used for Tunisian buildings air-heating application

    International Nuclear Information System (INIS)

    Highlights: • The study of a Solar Heating Prototype to prevail the buildings air-heating needs. • A parametric study of the system was achieved by means of the TRNSYS program. • The monthly internal temperature during cold months ranges between 22 and 25 °C. • The results shows that the relative humidity inside the monozone room of about 40%. - Abstract: This paper deals with the energetic performances of a Solar Heating Prototype (SHP) conceived in our laboratory to prevail the Tunisian households’ air-heating needs. The conceived SHP mainly consists of a flat-plate solar collector, solar hot water tank and an active layer integrated inside a single room. Firstly, a complete model is formulated taking into account various modes of heat transfer in the SHP by means of the TRNSYS simulation program. To validate the TRNSYS model, experimental tests under local weather conditions were performed for 2 days spread over 2 months (March and April 2013). Predicted results were compared to the measurements in order to determine the accuracy of the simulation program. A parametric study was then achieved by means of the TRNSYS program in order to optimize SHP design parameters (Collector area, collector mass flow rate, floor mass flow rate, storage tank volume and thickness of the active layer). The optimization of all design parameters shows that to achieve a maximum performances from the SHP it is essential to use a solar collector with an area equal to 6 m2 area, a collector mass flow rate equal to 100 kg h−1 and a hot water storage tank with a capacity equal to 450 l. Concerning the floor heating, the optimal values of mass flow rate and the active layer thickness are 200 kg h−1 and 0.06 m, respectively. The long-term SHP performances were afterward evaluated by means of the Typical Meteorological Year (TMY) data relative to Tunis, Tunisia. Results showed that for an annual total solar insolation of about 6493.37 MJ m−2 the average solar fraction

  15. Transfair. An air method of floor heating and cooling; Transfair. Procede de chauffage et de rafraichissement par le sol a air

    Energy Technology Data Exchange (ETDEWEB)

    Desvouas, C. [Tarnsfair TTR, 77 - Perthes en Gatinais (France)

    1997-12-31

    This paper presents the `Transfair` method which consists in the use of air instead of water in heating and cooling systems. This presentation comprises 4 parts. Part 1 is a general presentation of the activities of the French TTR company which has developed the Transfair method and its realizations in industrial space heating and in chemical industry (refrigeration units for sulfuric acid). Part 2 is a comparative evaluation of equivalent water and air systems in order to emphasize the advantages of air cooling systems (simplicity and reliability). Part 3 is a presentation of a software for the optimization of the dimensioning of components and investment costs of industrial air space heating systems. Part 4 is a presentation of the feasibility study of a floor cooled by air circulation and with a self-balancing of circuits confirmed by flow rate measurements. (J.S.)

  16. Talaromyces rubrifaciens, a new species discovered from heating, ventilation and air conditioning systems in China.

    Science.gov (United States)

    Luo, Yi; Lu, Xiaohong; Bi, Wu; Liu, Fan; Gao, Weiwei

    2016-01-01

    A new Talaromyces species, T. rubrifaciens, was isolated from supply air outlets of heating, ventilation and air conditioning (HVAC) systems in three kinds of public building in Beijing and Nanjing, China. Morphologically it exhibits many characters of section Trachyspermi but is distinguished from other species of this section by restricted growth and broad and strictly biverticillate conidiophores. Phylogenetic analyses based on the internal transcribed spacer rDNA (ITS), β-tubulin (BenA), calmodulin (CaM) and RNA polymerase second largest subunit (RPB2) genes reveal that T. rubrifaciens is a distinct species in section Trachyspermi. PMID:27055570

  17. INVESTIGATION OF THERMAL PERFORMANCE OF AIR TO WATER HEAT EXCHANGER USING NANO-FLUIDS

    OpenAIRE

    Nawaf Hazim Saeid

    2011-01-01

    In the present study the three-dimensional numerical simulation is selected as a tool to investigate the effectiveness of a cross flow heat exchanger. Water is selected to be mixed with nano-particles and flow inside a circular pipe while a pure air is flowing across it. Numerical simulations is carried out under laminar flow for both water and air sides. The thickness of the pipe is neglected in the present preliminary study. From the physics of the problem, the governing parameters can...

  18. Costic's technical day: thermodynamical heating and air conditioning in accommodations (heat pumps and heating/cooling floors). Air systems and their application in collective installations; Journee technique Costic: chauffage thermodynamique et climatisation dans l'habitat (les pompes a chaleur, les planchers chauffants-rafraichissants). Les systemes a air les applications en collectif

    Energy Technology Data Exchange (ETDEWEB)

    Lenotte, J.J.

    2002-07-01

    Direct expansion air systems are now currently used in individual residential houses. Some of these systems are used also in collective residential buildings where they allow to take into account the individualization of consumptions, as wished by some property developers. Some other centralized air-conditioning systems can be used. They require a distribution water loop for the supply of terminal units of ventilation-convection type. This document presents successively: the direct expansion air systems (direct emission air/air heat pumps, aeraulic distribution air/air heat pumps, production dimensioning, implementation, regulation, systems with variable flow rate of refrigerant); the centralized air/water systems with ventilation-convection systems (production dimensioning, implementation, regulation); the air distribution and diffusion. (J.S.)

  19. Changes in hydroxyapatite powder properties via heat treatment

    Indian Academy of Sciences (India)

    Y M Z Ahmed; S M El-Sheikh; Z I Zaki

    2015-12-01

    The properties of hydroxyaptite (HA) powder, especially its physical one, are largely influenced by the heat treatment process. Controlling of these changes is vital in deciding the suitability of applying this powder in wet processing routes for green body fabrication. Chemically, the crystallinity of the HA powder was found to be largely enhanced with the increase in calcination temperatures. In contrary, a high retardation in the carbonate ion content was found. Physically, all the powder properties in terms of particle size, its distribution, pore volume, pore size and surface area are considerably varied with calcination temperatures. It was found that HA powder calcined at both 1000 and 1100°C possesses reasonable physico-chemical properties for being applied in wet processing routes. Using heat-treated powder at 1000 and 1100°C with 0.3 wt% sodium polyacrylate (as a dispersing agent) turned out to be beneficial in developing a low viscosity and high turbidity suspensions.

  20. Applicability of Solid Solution Heat Treatments to Aluminum Foams

    Directory of Open Access Journals (Sweden)

    Miguel Rodríguez-Pérez

    2012-12-01

    Full Text Available Present research work evaluates the influence of both density and size on the treatability of Aluminum-based (6000 series foam-parts subjected to a typical solid solution heat treatment (water quenching. The results are compared with those obtained for the bulk alloy, evaluating the fulfilment of cooling requirements. Density of the foams was modeled by tomography analysis and the thermal properties calculated, based on validated density-scaled models. With this basis, cooling velocity maps during water quenching were predicted by finite element modeling (FEM in which boundary conditions were obtained by solving the inverse heat conduction problem. Simulations under such conditions have been validated experimentally. Obtained results address incomplete matrix hardening for foam-parts bigger than 70 mm in diameter with a density below 650 kg/m3. An excellent agreement has been found in between the predicted cooling maps and final measured microhardness profiles.

  1. High temperature heat treatment of 3 GHz niobium cavities

    International Nuclear Information System (INIS)

    We applied high temperature heat treatment to 3 GHz cavities to determine the preparation of niobium cavities using the titanium solid-state gettering process. Some preliminary results showed peak surface electric fields of up to 65 MV/m at a Q-factor of 2 x 1010. We evaluated improvement in the purity of the niobium by measuring the residual resistance ratio (RRR) at 10 K. The purest niobium we prepared reached a RRR of 670. To study the potential application to large-scale accelerator structures at lower frequencies, we are testing the possibility of heat treating the cavity half-cells before welding them. Therefore, we investigated the influence of electron beam welding on the RRR of high-purity niobium. In this paper we present the results of the investigations. (Author)3 figs., 2 tabs., 10 refs

  2. High temperature heat treatment of 3GHz niobium cavities

    International Nuclear Information System (INIS)

    We applied high temperature heat treatment to 3GHz cavities to determine the preparation of niobium cavities using the titanium solid-state gettering process. Some preliminary results showed peak surface electric fields of up to 65MV/m at a Q-factor of 2xlO10. We evaluated improvement in the purity of the niobium by measuring the residual resistance ratio (RRR) at 10K. The purest niobium we prepared reached a RRR of 670. To study the potential application to large-scale accelerator structures at lower frequencies, we are testing the possibility of heat treating the cavity half-cells before welding them. Therefore, we investigated the influence of electron beam welding on the RRR of high-purity niobium

  3. THE EFFECT OF HEAT TREATMENT ON SOME PROPERTIES AND COLOUR IN EUCALYPTUS (Eucalyptus camaldulensis DEHN.) WOOD

    OpenAIRE

    O Unsal; S Korkut; C Atik

    2003-01-01

    Heat treatment is often applied to some wood species to improve dimensional stability. This study evaluated the effect of heat treatment on some physical and mechanical properties and colour of Eucalyptus wood (Eucalyptus camaldulensis Dehn.), which has industrially high usage potential and large plantations in Turkey. Wood specimens from Tarsus, Turkey were subjected to heat treatment in varying temperatures and durations. After the heat treatment, hardness, swelling, ovendry density, and co...

  4. The impact of air flow to the distribution of heat transfer coefficient on circular cylinder

    Czech Academy of Sciences Publication Activity Database

    Beran, Pavel

    Vol. 1648. Melville, NY: AIP Publishing, 2015 - (Simos, T.; Tsitouras, C.), Č. 090006. (AIP Conference Proceedings. 1648). ISBN 978-0-7354-1287-3. ISSN 0094-243X. [International Conference on Numerical Analysis and Applied Mathematics (ICNAAM). Rhodes (GR), 22.09.2014-28.09.2014] R&D Projects: GA ČR(CZ) GBP105/12/G059 Keywords : transient heat transfer * heat transfer coefficient * air flow * finite element method * Reynolds number * climatic tunnel Subject RIV: JN - Civil Engineering http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4912394

  5. Towards energy efficient operation of Heating, Ventilation and Air Conditioning systems via advanced supervisory control design

    Science.gov (United States)

    Oswiecinska, A.; Hibbs, J.; Zajic, I.; Burnham, K. J.

    2015-11-01

    This paper presents conceptual control solution for reliable and energy efficient operation of heating, ventilation and air conditioning (HVAC) systems used in large volume building applications, e.g. warehouse facilities or exhibition centres. Advanced two-level scalable control solution, designed to extend capabilities of the existing low-level control strategies via remote internet connection, is presented. The high-level, supervisory controller is based on Model Predictive Control (MPC) architecture, which is the state-of-the-art for indoor climate control systems. The innovative approach benefits from using passive heating and cooling control strategies for reducing the HVAC system operational costs, while ensuring that required environmental conditions are met.

  6. Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow

    OpenAIRE

    Teng Tun-Chien; Teng Tun-Ping; Hung Yi-Hsuan; Chen Jyun-Hong

    2011-01-01

    Abstract This study analyzes the characteristics of alumina (Al2O3)/water nanofluid to determine the feasibility of its application in an air-cooled heat exchanger for heat dissipation for PEMFC or electronic chip cooling. The experimental sample was Al2O3/water nanofluid produced by the direct synthesis method at three different concentrations (0.5, 1.0, and 1.5 wt.%). The experiments in this study measured the thermal conductivity and viscosity of nanofluid with weight fractions and sample ...

  7. Adaptive individual-cylinder thermal state control using intake air heating for a GDCI engine

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Gregory T.; Sellnau, Mark C.

    2016-08-09

    A system for a multi-cylinder compression ignition engine includes a plurality of heaters, at least one heater per cylinder, with each heater configured to heat air introduced into a cylinder. Independent control of the heaters is provided on a cylinder-by-cylinder basis. A combustion parameter is determined for combustion in each cylinder of the engine, and control of the heater for that cylinder is based on the value of the combustion parameter for combustion in that cylinder. A method for influencing combustion in a multi-cylinder compression ignition engine, including determining a combustion parameter for combustion taking place in a cylinder of the engine and controlling a heater configured to heat air introduced into that cylinder, is also provided.

  8. Performance tests of air source heat pumps under frosting conditions. Quality of results

    Science.gov (United States)

    Fahlen, P.

    This report focuses on the analysis of uncertainties in research regarding air-source heat pumps. The principles recommended by the Western European Calibration Conference (WECC) are applied and the generated information is condensed in the form of uncertainty budgets. The ensuring discussion, and the Measurement Assurance Program that was applied during the research work are also relevant to general testing of cooling coils, e.g. for air source heat pumps. The general conclusion of the analysis is that the method of determining frost mass by continuous weighing and frost density by inference from pressure drop considerations, which is presented in the report, has the potential to produce results with an accuracy on a par with the best previously used techniques to investigate frosting and defrosting phenomena. Furthermore, the methodology has the distinct advantage of yielding online measuring possibilities and being much less time consuming than traditional techniques.

  9. Heat release from B4C oxidation in steam and air

    International Nuclear Information System (INIS)

    BWR and some PWR cores contain boron carbide (B4C) as neutron absorber. During a severe accident, the B4C can potentially react with steam under release of heat and hydrogen. Although models for B4C oxidation already exist in MELCOR and SCDAP/RELAP5, a development of a new model for another computer code seems to be difficult due to a missing comprehensive description of the current modelling methodology and scarce experimental data. The aim of this paper is to highlight the key points of the B4C oxidation using the existing available experimental data and to perform a simple heat balance analysis of the B4C/steam and B4C/air chemical reactions. The analysis of literature data shows that the B4C oxidation phenomenon is qualitatively well described below 1000 deg. C. However, no reliable data exist for the reaction kinetics especially above this temperature. It was found that the experimental results strongly depend on the experimental arrangement. The reaction heats, calculated in this study, indicate that the B4C oxidation is an exothermic reaction, releasing more heat in air than in steam. The formation of boric acids from the boron oxide increases the heat release from B4C by ∼ 10%, in the worst case. Although the total heat, released in a PWR core from the B4C oxidation, is probably much smaller than the heat released from the Zr/steam reaction, it is not excluded that the B4C oxidation can locally contribute to the damage of the control elements due to local overheating. Modelling of these phenomena is, however, very difficult due to the complex geometry of the liquefied control elements and due to absence of suitable data on the reaction kinetics. (author). 25 refs, 2 figs, 3 tabs

  10. Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

    International Nuclear Information System (INIS)

    The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial

  11. Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

    Energy Technology Data Exchange (ETDEWEB)

    Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

    1981-01-01

    The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial.

  12. Influence of supply of heat to cobalt-chromium frameworks during soldering and subsequent hardening heat treatment of wrought clasps.

    Science.gov (United States)

    Eriksson, T; Sjögren, G; Bergman, M

    1983-01-01

    Retentive clasp arms of wrought gold alloy wire were soldered to frameworks made of three dental cobalt-chromium alloys. The clasps were then subjected to a conventional hardening heat treatment. Microstructure and hardness of the cobalt-chromium alloys were determined before and after these operations. The results reveal that the supply of heat during soldering and hardening heat treatment of the clasp does not influence the microstructure and hardness of the cobalt-chromium alloys. PMID:6134347

  13. Some Aspects Concerning Convective Circulation Mode of Heat Transfer in Furnace to Wood Heat Treatment

    OpenAIRE

    Nadia Potoceanu

    2007-01-01

    The paper presented the most aspects of convective circulate mode of heat transfer : heat transfer through the boundary layer formed at the surface of the heat generator; heat transfer in the heat carrier and heat transfer through the boundary layer formed at the heated surface

  14. Treatment of hydraulic fracturing wastewater by wet air oxidation.

    Science.gov (United States)

    Wang, Wei; Yan, Xiuyi; Zhou, Jinghui; Ma, Jiuli

    2016-01-01

    Wastewater produced by hydraulic fracturing for oil and gas production is characterized by high salinity and high chemical oxygen demand (COD). We applied a combination of flocculation and wet air oxidation technology to optimize the reduction of COD in the treatment of hydraulic fracturing wastewater. The experiments used different values of flocculant, coagulant, and oxidizing agent added to the wastewater, as well as different reaction times and treatment temperatures. The use of flocculants for the pretreatment of fracturing wastewater was shown to improve treatment efficiency. The addition of 500 mg/L of polyaluminum chloride (PAC) and 20 mg/L of anionic polyacrylamide (APAM) during pretreatment resulted in a COD removal ratio of 8.2% and reduced the suspended solid concentration of fracturing wastewater to 150 mg/L. For a solution of pretreated fracturing wastewater with 12 mL of added H2O2, the COD was reduced to 104 mg/L when reacted at 300 °C for 75 min, and reduced to 127 mg/L when reacted at the same temperature for 45 min while using a 1 L autoclave. An optimal combination of these parameters produced treated wastewater that met the GB 8978-1996 'Integrated Wastewater Discharge Standard' level I emission standard. PMID:26942530

  15. 1983-2004 Heat Treatment Embraces Surface Engineering

    Institute of Scientific and Technical Information of China (English)

    Tom Bell

    2004-01-01

    The origins of surface engineering lie in antiquity, with the practices in ancient Greece and China of hardening,tempering and crude form of case hardening using solid organic materials. The formation of the International Federation for Heat Treatment in 1971 later to include Surface Engineering has been pre-eminent in the globalisation of the rapidly developing discipline of surface engineering. The dominant effect of environmental aspects of surface engineering are discussed regarding the impact for change to light weight materials and the adoption of environmentally friendly plasma technologies.

  16. COMPUTERIZED HEAT-TREATMENT IN A ZIMBABWEAN FACTORY

    Directory of Open Access Journals (Sweden)

    M. Collier

    2012-01-01

    Full Text Available In the context of Zimbabwe's current economic problems, parts of the manufacturing industry are turning their attention to the possibility of utilising local design talent in upgrading their manufacturing plants. This paper describes a project undertaken by the National University of Science and Technology to convert the heat-treatment process in a major manufacturing plant from semi -manual to a computerized one. The system comprises microcontroller connection to the furnaces and sensors, and communicates with a central computer on which software for a windowed user-interface is hosted. Experimental results for the system are presented, and a strategy for other companies in the same predicament is proposed.

  17. Air and Water Flow Rate Optimisation For a Fan Coil Unit in Heat Pump Applications

    OpenAIRE

    Edwards, Killian C.; Finn, Donal

    2012-01-01

    The degradation in efficiency of auxiliary components in heating/cooling systems when operating at part load is frequently reported. Through the use of variable speed components, the supplied capacity can be reduced to match the required load and hence reduce unnecessary energy consumption. However, for fan coil units, difficulties can arisewhen optimizing fan and pump speeds at part load. Practicallylocating optimal water and air flowrates from readily available information and for varying s...

  18. Air and Water Flowrate Optimisation for a Fan Coil Unit in Heat Pump Systems

    OpenAIRE

    Kilian, Edwards; Finn, Donal P.

    2012-01-01

    The degradation in efficiency of auxiliary components in heating/cooling systems when operating at part load is frequently reported. Through the use of variable speed components, the supplied capacity can be reduced to match the required load and hence reduce unnecessary energy consumption. However, for fan coil units, difficulties can arise when optimizing fan and pump speeds at part load. Practically locating optimal water and air flow rates from readily available information and for varyin...

  19. Fault Detection And Diagnosis For Air Conditioners And Heat Pumps Based On Virtual Sensors

    OpenAIRE

    Kim, Woohyun

    2013-01-01

    The primary goal of this research is to develop and demonstrate an integrated, on-line performance monitoring and diagnostic system with low cost sensors for air conditioning and heat pump equipment. Automated fault detection and diagnostics (FDD) has the potential for improving energy efficiency along with reducing service costs and comfort complaints. To achieve this goal, virtual sensors with low cost measurements and simple models were developed to estimate quantities that would be expens...

  20. Development and Testing of Supercharger Compressor for Cold Climate Air Source Heat Pumps

    OpenAIRE

    Walter, Thomas; Jonas, Travis

    2014-01-01

    The on-going development of a compact centrifugal compressor as a first stage or pre-compressor for cold climate operation of heat pumps is described. Positioned in the low pressure vapor portion of the refrigerant loop, this compressor will, on cold days, operate automatically to boost refrigerant pressure, in a manner similar to the way an automotive supercharger pressurizes air. The single stage motor driven centrifugal compressor runs on oil-free bearings. It is being configured to work i...

  1. Energy-smart calculation of thermal loads in mobile and stationary heating, ventilation, air conditioning, and refrigeration systems

    OpenAIRE

    Fayazbakhsh, Mohammad Ali

    2015-01-01

    The energy consumption by heating, ventilation, air conditioning, and refrigeration systems forms a large portion of the total energy usage in buildings. Vehicle fuel consumption and emissions are also significantly affected by air conditioning. Air conditioning is also a critical system for hybrid electric vehicles and electric vehicles as the second most energy consuming system after the electric motor. Proper design and efficient operation of air conditioning systems require accurate calcu...

  2. Analysis of heat recovery from a spray dryer by recirculation of exhaust air

    International Nuclear Information System (INIS)

    Highlights: • We study a spray dryer with heat recovery by partial recirculation of exhaust air. • We examine effects of process parameters on energy efficiency and energy savings. • Decreasing drying air temperature and flow rate will increase energy efficiency. • Increasing recirculation ratio and slurry feed rate will increase energy efficiency. - Abstract: Model simulations were employed to investigate the influences of process parameters on the energy recovery in spray drying process that partially recycle the exhaust drying gas. The energy efficiency and energy saving were studied for various values of recirculation ratios with respect to the temperature and flow rate of the drying air, slurry feed rate and concentration of slurry in spray drying of advanced ceramic materials. As a result, significant gains in energy efficiency and energy saving were obtained for a spray drying system with high recirculation ratio of exhaust air. The high slurry feed rate and the low slurry concentration, inlet drying air temperature and drying air flow rate enhanced the energy efficiency of spray drying system. However, the high energy saving was obtained in spray dryers operating at low slurry feed rate and high slurry concentration

  3. Study of air vent design for inverted U-tube type heat exchanger

    International Nuclear Information System (INIS)

    A two-phase flow has characteristics of the blockage instability in which voids prevent and stop the water flow in an inverted U-tube. In cooler c32 employing inverted U-tubes, changes of heat transfer performance, abnormal mechanical vibrations and corrosions on the surfaces of cooling tubes had been observed during the operations of HENDEL (Helium Engineering Demonstration Loop). It was assumed that the causes of these abnormal events were air stagnated in inverted U-tubes when cooling water was filled before HENDEL operation. A blockage instability of two-phase flow and stability boundaries were investigated with an experimental apparatus composed of water plenums and an inverted U-tube which is parallel to a bypass channel. 'Dynamic air vent' and 'Vacuum air vent' methods were additionally suggested to reject the stagnated air in the inverted U-tubes. As the results of experiments, the possibility of Dynamic air vent method was verified using the experimental apparatus. And, the usefulness of Vacuum air vent method was also demonstrated through the tests employing cooler C32 of HENDEL. (author)

  4. Air flow test of MK-III dump heat exchanger tube arrays for JOYO

    Energy Technology Data Exchange (ETDEWEB)

    Isozaki, Kazunori; Kawahara, Hirotaka; Tomita, Naoki [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1997-07-01

    The reactor thermal power of JOYO MK-III is to be increased from 100MWt to 140MWt due to high performance of reactor core. So, Dump Heat Exchanger(DHX) of MK-III was designed to improve its heat removal capability by changing U type heat transport tube arrays to {Sigma} type tube arrays and increasing air flow. Natural frequency between support and support of MK-III DHX`s tube arrays was about 15Hz, and Karman vortex shedding frequency of tube arrays was about 90Hz by Y.N.Chen`s report. Then, a possibility of piling up of Karman vortex shedding frequency in high frequency mode was to be considered. And, air velocity of flow tube arrays is also increased compared to the MK-II DHX. Sodium leak accident of MONJU was caused by a flow-induced vibration of thermometer well. Therefore, the air flow test to tube arrays of MK-III DHX was conducted. High cycles fatigue damage of tube arrays was evaluated. Since, peak stress is below 2kg/mm{sup 2}, it can be said that high cycles fatigue damage of tube arrays by Karman vortex shedding vibration will not be caused. (J.P.N.)

  5. Leachate Treatment UsingWet Air Oxidation Processes

    Directory of Open Access Journals (Sweden)

    A Ebrahimi

    2011-04-01

    Full Text Available "nBackground and Objectives: Wet air oxidation (WAO is One of the advanced oxidation process which reduce organic matter concentration from industrial wastewater, toxic and non biodegradable substances and, solid waste leachate,etc. In this study the efficiency of wet air oxidation method in leachate treatment generating from Esfahan Composting factory was Evaluated."nMaterial and Methods: The experiment was carried out by adding 1.5 Lit of pretreated leachate sample the steel reactor with the volume of 3L. The reactor then underwent10 bar pressure at different temperature (100, 200 and 300 °C and various retention time (30, 60 and 90 min. Leachate sample in 18 stages from composting factory in Isfahan in the volume of 20 Lit was taken and the WAO method, was used for pre-treatments. Removal efficiency of COD, BOD, NH4-N, NO3 and TSS were examined."nResults: The results showed that the removal efficiency was more than 35% for COD, 38% for BOD, and 85% for TSS within one hour of reaction. The Maximum removal efficiency obtained in this study were 53.3% for NH4-N and 73.9 % forNO3-N."nConclusion: the results indicate that the reaction temperatures are the most important factors affecting degradation of organic matter. COD and BOD5 removal efficiency by WAO process increased as the time of reaction went up. In addition, BOD5/COD ratios of the effluents, which are generally regarded as an important index of biodegradability of leachate sample, were determined and improved grately as it reached to 84%. TheWAO process presented in this paper is considered an efficient process for pretreatment of leachate, as the COD, BOD5 and NO3 reduction observed in leachate samples.

  6. Heat supply of the Therme Erding spa. Lower operating cost with a hot-air heating system; Waermeversorgung in der Therme Erding. Geringere Betriebskosten durch eine Heissluftheizung

    Energy Technology Data Exchange (ETDEWEB)

    Landwehr, Elke [Systemair GmbH, Boxberg-Windischbuch (Germany). Vertriebsleitung Deutschland

    2009-07-01

    The ''Therme Erding'' spa comprises 26 different saunas and is one of the biggest indoor spas world-wide. It has an unusual hot air heating system. Optimal air circulation is ensured by blowers that work in continuous operation at temperatures up to 95 degC. (orig.)

  7. Experimental study of an air-source heat pump for simultaneous heating and cooling - Part 2: Dynamic behaviour and two-phase thermosiphon defrosting technique

    International Nuclear Information System (INIS)

    Highlights: → Experimental study of an air-source heat pump for simultaneous heating and cooling. → Operating sequences alternating between heating, cooling and simultaneous modes. → Validation of the high pressure control system. → Validation of the non-penalizing two-phase thermosiphon defrosting sequence. - Abstract: This article presents the concepts of an air-source heat pump for simultaneous heating and cooling (HPS) designed for hotels and smaller residential, commercial and office buildings in which simultaneous needs in heating and cooling are frequent. The main advantage of the HPS is to carry out simultaneously space heating and space cooling with the same energy input. Ambient air is used as a balancing source to run a heating or a cooling mode. The second advantage is that, during winter, energy recovered by the subcooling of the refrigerant is stored at first in a water tank and used subsequently as a cold source at the water evaporator to improve the average performance and to carry out defrosting of the air evaporator using a two-phase thermosiphon. Unlike conventional air-source heat pumps, defrosting is carried out without stopping the heat production. A R407C HPS prototype was built and tested. The basic concepts of the HPS are detailed in part1 of this article . Its performance on defined operating conditions corresponds to the data given by the selection software of the compressor manufacturer. In the present part of this article, the operation of the high pressure control system, the transitions between heating, cooling and simultaneous modes and the defrosting sequence are analysed and validated experimentally.

  8. Cotton gin trash incinerator-air heat project. Consultant report (final)

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    The California Energy Commission has funded the final phase of a four year project resulting in development of a successful system for burning cotton gin trash as a fuel providing the heat for ginning. The incinerator - air heater system installed in Corcoran, California operates continuously throughout the ginning season. Trash feeding and burning rate is automatically controlled from the combustion temperature, hot air temperature is controlled by the drying needs, and ashes are automatically removed from the system and pneumatically conveyed to the disposal site. The system complies with state and county air pollution codes by means of baghouse collectors. Savings in fossil fuel and trash disposal costs have demonstrated the equipment system is feasible for a four year payback at large, well utilized gins.

  9. Numerical study on the heat storing capacity of concrete walls with air cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.L. [Dept. of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Wachenfeldt, B.J. [SINTEF Technology and Society, Institute for Architecture and Building Technology, Trondheim (Norway)

    2009-07-15

    Finite element analyses using COMSOL have been carried out to study the heat transfer behavior and storing capacity of concrete walls with air cavities, and to explore the possibility of using one-layer and two-layer one-dimensional models with equivalent thermal conductivity and mass density to represent the effect of concrete walls with air cavities in a building energy simulation. Three typical wall geometries were chosen and both stationary and transient analyses have been carried out. The stationary analyses were performed first to find the equivalent thermal conductivity which was further used in the transient analyses to fit the equivalent mass density. Because of the presence of air cavities the equivalent thermal conductivities are always smaller than the bulk thermal conductivity. However, for the one-layer model an exaggerated equivalent mass density as high as two times the bulk density should be used in order to simulate the heat storing capacity of the concrete walls with air cavities. The values of the fitted equivalent mass density are strongly dependent on the wall thickness. (author)

  10. Tools for Performance Simulation of Heat, Air and Moisture Conditions of Whole Buildings

    DEFF Research Database (Denmark)

    Woloszyn, Monika; Rode, Carsten

    2008-01-01

    Humidity of indoor air is an important factor influencing the air quality and energy consumption of buildings as well as durability of building components. Indoor humidity depends on several factors, such as moisture sources, air change, sorption in materials and possible condensation. Since all ...... place without a coherent and complete description of all hygrothermal processes. This paper will illustrate some of the modelling work that has taken place within the project and present some of the simulation tools used....... these phenomena are strongly dependent on each other, numerical predictions of indoor humidity need to be integrated into combined heat and airflow simulation tools. The purpose of a recent international collaborative project, IEA ECBCS Annex 41, has been to advance development in modelling the integral...... heat, air and moisture transfer processes that take place in “whole buildings” by considering all relevant parts of its constituents. It is believed that full understanding of these processes for the whole building is absolutely crucial for future energy optimization of buildings, as this cannot take...

  11. Assessment of heat treatment of various types of milk.

    Science.gov (United States)

    Sakkas, Lambros; Moutafi, Alexandra; Moschopoulou, Ekaterini; Moatsou, Golfo

    2014-09-15

    Raw milk (RM), reconstituted condensed milk (CM) and three types of reconstituted milk powders (SMPs) were heated indirectly at 80-140°C for 4 s. Native β-lactoglobulin after 90°C treatment of RM was 1132±167 mg/L but no reliable quantities were estimated at temperatures >100°C, whereas 218±43 mg/L residual α-lactalbumin were found at 130°C. Average lactulose contents from 51 to 1549 mg/L were detected at ⩾100°C; average furosine was 1.9 and 126.5 mg/L in raw and 140°C treated milks respectively. The behaviour of heated CM was similar to that of heated RM except for higher furosine concentration. Reconstituted SMPs contained high quantities of lactulose and furosine, the ratio of which was lower than in similarly treated RM. Among the market milks analysed, the group of high-pasteurised milks was highly variable; i.e. native β-lactoglobulin was 69-2831 mg/L, lactulose 0-824 mg/L and furosine 3.3-68.8 mg/L. PMID:24767058

  12. Investigation into the aerodynamic processes of air treatment using a plate-type biofilter.

    Science.gov (United States)

    Baltrėnas, Pranas; Kleiza, Jonas; Idzelis, Raimondas Leopoldas

    2016-03-01

    The research conducted has involved a laboratory stand of a plate-type air treatment biofilter with a capillary system for humidifying packing material composed of polymer plates vertically arranged next to each other and producing a capillary effect of humidification. The pattern of arranging the plates has sufficiently large spaces (6 mm), and therefore the use of the plate-type structure decreases the aerodynamic resistance of the device. Slightly pressed slabs attached on both sides of the plates are made of heat-treated wood fibre, to increase the longevity of which, wood waste has been heat-treated in the steam explosion reactor under the pressure of 32 bars and a temperature of 235°C. This is the method for changing the molecular structure of wood, which stops the decay of wood fibre in a humid environment and thus increases the life span of biofilter plates. The research performed has disclosed that, under the application of the above introduced structure of the biofilter, the aerodynamic resistance of the biofilter reaches 1 ÷ 5 Pa when the rate of the air flow passing through the device makes 0.08 m/s. For evaluating the reliability of the obtained results, the theoretical model has been applied. PMID:26207569

  13. Investigation of heat distribution during magnetic heating treatment using a polyurethane–ferrofluid phantom-model

    Energy Technology Data Exchange (ETDEWEB)

    Henrich, F.; Rahn, H.; Odenbach, S., E-mail: stefan.odenbach@tu-dresden.de

    2014-02-15

    Magnetic heating treatment can be used as an adjuvant treatment for cancer therapy. In this therapy, magnetic nanoparticles are enriched inside the tumour and exposed to an alternating magnetic field. Due to magnetic losses the temperature in the tumour rises. The resulting temperature profile inside the tumour is useful for the therapeutic success. In this context heat transfer between tissue with nanoparticles and tissue without nanoparticles is a highly important feature which is actually not understood in detail. In order to investigate this, a phantom has been created which can be used to measure the temperature profile around a region enriched with magnetic nanoparticles. This phantom is composed of a material, which has similar thermal conductivity as human tissue. A tempered water bath surrounds the phantom to establish a constant surrounding temperature simulating the heat sink provided by the human body in a real therapeutic application. It has been found that even at a low concentration of magnetic nanoparticles around 13 mg/ml, sufficient heating of the enriched region can be achieved. Moreover it has been observed that the temperature drops rapidly in the material surrounding the enriched region. Corresponding numerical investigations provide a basis for future recalculations of the temperature inside the tumour using temperature data obtained in the surrounding tissue. - Highlights: • The temperature profile by magnetic hyperthermia was examined. • A model was built to get a deeper understanding of the temperature profile. • The temperature profile of the model inside magnetic fields was measured. • Based on the model a simulation of the temperature profile was performed. • The simulated temperature profile agreed well with the measured profile.

  14. Investigation of heat distribution during magnetic heating treatment using a polyurethane–ferrofluid phantom-model

    International Nuclear Information System (INIS)

    Magnetic heating treatment can be used as an adjuvant treatment for cancer therapy. In this therapy, magnetic nanoparticles are enriched inside the tumour and exposed to an alternating magnetic field. Due to magnetic losses the temperature in the tumour rises. The resulting temperature profile inside the tumour is useful for the therapeutic success. In this context heat transfer between tissue with nanoparticles and tissue without nanoparticles is a highly important feature which is actually not understood in detail. In order to investigate this, a phantom has been created which can be used to measure the temperature profile around a region enriched with magnetic nanoparticles. This phantom is composed of a material, which has similar thermal conductivity as human tissue. A tempered water bath surrounds the phantom to establish a constant surrounding temperature simulating the heat sink provided by the human body in a real therapeutic application. It has been found that even at a low concentration of magnetic nanoparticles around 13 mg/ml, sufficient heating of the enriched region can be achieved. Moreover it has been observed that the temperature drops rapidly in the material surrounding the enriched region. Corresponding numerical investigations provide a basis for future recalculations of the temperature inside the tumour using temperature data obtained in the surrounding tissue. - Highlights: • The temperature profile by magnetic hyperthermia was examined. • A model was built to get a deeper understanding of the temperature profile. • The temperature profile of the model inside magnetic fields was measured. • Based on the model a simulation of the temperature profile was performed. • The simulated temperature profile agreed well with the measured profile

  15. Air CHP, a new concept in small-scale space heating

    Energy Technology Data Exchange (ETDEWEB)

    Mullins, P.

    1996-10-01

    A new type of combined heat and power (CHP) system claimed to be capable of providing electrical and thermal power with efficiencies in the region of 95% is being marketed by Aircogen Ltd, a company launched by turbine and compressor manufacturer Peter Brotherhood. Power generation capabilities range from 50 to 1500 kW. VarityPerkins has played a large part in supplying spark-ignited gas engines for the first installations of this new system from the group`s plants in Stafford and Shrewsbury, U.K. Aircogen has developed a system in which the air for heating the building is heated direct from the gen-set. This provides a further source of extracted heat and contributes to the extremely high thermal efficiencies. The system lends itself particularly to swimming pools, supermarkets, leisure centers, or any building where large spaces need to be heated for prolonged periods and where normally low-pressure hot water heating would be used. This paper describes briefly the design, specifications and typical applications.

  16. Simulation of an Air-Source Heat Pump with Two-Stage Compression and Economizing for Cold Climates

    OpenAIRE

    Caskey, Stephen L.; Kultgen, Derek; Eckhard A. Groll; Hutzel, William; Menzi, Tobias

    2012-01-01

    A new air-source heat pump technology optimized for cold climates was designed and fabricated by the authors in close cooperation with three industrial partners. The constructed unit will undergo a field demonstration in a military barrack to identify heat pumps as cost effective systems that have less primary energy consumption when compared to traditional cold climate heating methods. A simulation model developed in EES predicted the designed heat pump performance at different ambient condi...

  17. Measurement of the thermal performance of a Borehole Heat Exchanger while injecting air bubbles in the groundwater

    OpenAIRE

    Calzada i Oliveras, Eduard

    2012-01-01

    The most common way to exchange heat with the ground in Ground Source Heat Pump (GSHP) applications is with borehole heat exchangers (energy col-lectors in vertical wells). These boreholes contain the pipe with the secondary fluid of the GSHP and they are often filled with natural groundwater. It has been recently discovered that injecting air bubbles in the groundwater side of the boreholes increases the efficiency of the heat transfer. The aim of this thesis is to analyze the thermal change...

  18. Experimental study of an air-source heat pump for simultaneous heating and cooling - Part 1: Basic concepts and performance verification

    International Nuclear Information System (INIS)

    This article presents the concepts of an air-source heat pump for simultaneous heating and cooling (HPS) designed for hotels and smaller residential, commercial and office buildings in which simultaneous needs in heating and cooling are frequent. The main advantage of the HPS is to carry out simultaneously space heating and space cooling with the same energy input. Ambient air is used as a balancing source to run a heating or a cooling mode. The second advantage is that, during winter, energy recovered by the subcooling of the refrigerant is stored at first in a water tank and used subsequently as a cold source at the water evaporator to improve the average performance and to carry out defrosting of the air evaporator using a two-phase thermosiphon. Unlike conventional air-source heat pumps, defrosting is carried out without stopping the heat production. A R407C HPS prototype was built and tested. Its performance on defined operating conditions corresponds to the data given by the selection software of the compressor manufacturer. The operation of the high pressure control system, the transitions between heating, cooling and simultaneous modes and the defrosting sequence were validated experimentally and are presented in the second part of this article .

  19. Particle growth mechanism of nanocrystalline zirconia powder during high temperature heat treatment

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Agglomerated nanocrystalline ZrO2-8%Y2O3 powder prepared by spray drying was heat-treated in air at temperatures from 1 200 ℃ to 1 400 ℃ for 2 h. Scanning electron microscopy was used to examine the changes of particle size and morphology,and X-ray diffraction was used to analyze the change of constituent phases before and after the high temperature heat treatment.Nano-particle growth behavior was also investigated. The results show that the major constituent phase of the agglomerated nanocrystalline powder is tetragonal, and non-uniform growth of the nano-particles occurs while the heat treatment temperature reaches 1 300 ℃. This non-uniform growth phenomenon is related with the inhomogeneous distribution of Y2O3 in ZrO2.Nano-particles grow into micron particles through the mechanisms of gradual merging of nano-particles in some areas and sudden merging of nano-particles in other areas.

  20. Thermal partition of two asymmetric discrete heat sources by cold air curtain

    Institute of Scientific and Technical Information of China (English)

    DENG Quan-wei; DENG Qi-hong

    2005-01-01

    A partition solution implemented by a cold air curtain for two asymmetric discrete heat sources in a twodimensional rectangular enclosure was numerically studied. Main attentions were focused on the effects of Reynolds number, Grashof number, separation distance between heat sources, and buoyancy ratio. It is found that the airflow and heat transfer are not only determined by governing parameters, but also affected by boundary conditions. It is also found that nearly symmetry of flow structure corresponds to nearly thermal partition, and the symmetry can be enhanced when Reynolds number, separation distance and buoyancy ratio increase. In addition, it is observed that there is a minimum Reynolds number for obtaining nearly thermal partition, which increases when Grashof number increases.

  1. Air-Cooled Heat Exchanger for High-Temperature Power Electronics: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S. K.; Lustbader, J.; Musselman, M.; King, C.

    2015-05-06

    This work demonstrates a direct air-cooled heat exchanger strategy for high-temperature power electronic devices with an application specific to automotive traction drive inverters. We present experimental heat dissipation and system pressure curves versus flow rate for baseline and optimized sub-module assemblies containing two ceramic resistance heaters that provide device heat fluxes. The maximum allowable junction temperature was set to 175 deg.C. Results were extrapolated to the inverter scale and combined with balance-of-inverter components to estimate inverter power density and specific power. The results exceeded the goal of 12 kW/L and 12 kW/kg for power density and specific power, respectively.

  2. Effect of geometric factors on performance of a sodium to air heat exchanger in a fast breeder reactor

    International Nuclear Information System (INIS)

    Highlights: • A heat exchanger analysis (HE) before scale up reduces excess heat transfer area. • Representative Elementary Volume analysis of a HE speeds up the solution. • The error in air temperature rise prediction by numerical across HE is within 5%. • When both pitches are reduced, the maximum increase in heat flux is experienced. • The experience has resulted in better design of next level heat exchangers. - Abstract: Prototype fast breeder reactor (PFBR) has a safety grade decay heat removal system whose performance depends on the effective functioning of natural convection heat exchangers called sodium to air heat exchangers. The development of Representative Elementary Volume (REV) model for the sodium to air heat exchanger is necessary to envisage its design and to study the effect of various factors for continuous improvement in design. With a Representative Elementary Volume, the hydrodynamic and heat transfer characteristics of the heat exchanger was studied and the results agree well with experimental data. The effect of longitudinal pitch and transverse pitch on the heat exchanger performance has been studied and an improvement of 22% in heat transfer is predicted

  3. Solar air heating systems. IEA solar heating and cooling programme - task 19. Final report; Luftsolvarmesystemer. Dansk deltagelse i IEA task 19. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    This project focuses on tools for analysis, development and optimization of systems and buildings with solar air-based heating systems. The results are collected in engineering handbook and in a `case study book` with examples of solar-heated buildings. The latter book is addressed to the architects as the primary target group. A component catalog for solar heating systems has been collected and will be published in the same time as the two handbooks. (EG)

  4. Effect of Air Cleaning Technologies in Conjunction With the Use of Rotary Heat Exchangers in Residential Buildings

    DEFF Research Database (Denmark)

    Afshari, Alireza; Bergsøe, Niels Christian; Ekberg, Lars

    2013-01-01

    This study is part of a research project concerning the possibilities of applying efficient air cleaning technologies using rotary heat exchanger in residential buildings. The purpose of this project was to identify and adapt new air-cleaning technologies for implementation in HVAC systems...... with rotary air-to-air heat exchangers. For this purpose, a mechanical filter with low pressure drop and a 4 cm thick activated carbon filter were selected for testing in a laboratory environment. The measurements included testing of the filters, separately and combined, in a ductwork to study the efficiency...

  5. Zoning of the territory of Russia by the effectiveness of low-potential heat of the ground and atmospheric air for heating buildings

    Science.gov (United States)

    Vasilyev, G. P.; Kolesova, M. V.; Gornov, V. F.; Yurchenko, I. A.

    2016-06-01

    The article represents the results of researches to zone the territory of Russia and Europe division into districts of by efficiency of using for the heat supply of buildings of low-potential thermal energy of ground and free air and their combination. While modeling the heat regime of geothermal HPS in climatic conditions of different regions of the territory of Russia, the influence of the long-term extraction of geothermal heat energy on the ground heat regime has been taken into account as well as the influence of phase transitions of pore moisture in ground on the efficiency of operation of geothermal heat-pump heat-supply systems. Also considered were the sinking of temperatures of ground massif by long-term extraction of the heat energy from the ground as calculation parameters of the heat energy from the ground, and as calculation parameters of ground massif temperatures.

  6. Effect of two-steps heat treatment on the mechanical properties and magnetostriction of oriented TbDyFe giant magnetostrictive material

    International Nuclear Information System (INIS)

    oriented rods of TbDyFe giant magnetostrictive alloy have been prepared by zone melting directional solidification method. Two steps heat treatments were performed at 1353 K for 2 h, followed by heating at 673, 773, 873, 973 K for 4 h in argon atmosphere and air cooling. The effect of a two steps heat treatment on the mechanical properties, fractography and magnetostriction of TbDyFe has been studied. It was found that the largest values of impact toughness, compression strength and magnetostriction were achieved when the alloy was heat-treated at 873 K. Room temperature Vickers indentation was performed to access the fracture toughness, and with heating temperature increasing from 673 to 973 K, the fracture toughness was gradually improved. The change of mechanical properties and magnetostriction of TbDyFe was due to a change of the relative dimensions and distribution of the rare earth-rich phase caused by the two steps heat treatment

  7. An experimental study of the air-side particulate fouling in finned-tube heat exchangers of air conditioners through accelerated tests

    International Nuclear Information System (INIS)

    The air-side particulate fouling in the heat exchangers of HVAC applications degrades the performance of cooling capacity, pressure drop across a heat exchanger, and indoor air quality. Indoor and outdoor air contaminants foul heat exchangers. The purpose of this study is to investigate the fouling characteristics trough accelerated tests. The fouling characteristics are analyzed as functions of a dust concentration (1.28 and 3.84 g/m3), a face velocity (0.5, 1.0, and 1.5 m/s), and a surface condition. The cooling capacity in the slitted finned-tube heat exchangers at the face velocity of 1 m/s decreases about 2% and the pressure drop increases up to 57%. The rate of build-up of fouling is observed to be 3 times slower for this three-fold reduction of dust concentration whilst still approaching the same asymptotic level

  8. The Effects of Heat Treatment and Microstructure Variations on Disk Superalloy Properties at High Temperature

    Science.gov (United States)

    Gabb, Timothy P.; Gayda, John; Telesman, Jack; Garg, Anita

    2008-01-01

    The effects of heat treatment and resulting microstructure variations on high temperature mechanical properties were assessed for a powder metallurgy disk superalloy LSHR. Blanks were consistently supersolvus solution heat treated and quenched at two cooling rates, than aged at varying temperatures and times. Tensile, creep, and dwell fatigue crack growth tests were then performed at 704 C. Gamma' precipitate microstructures were quantified. Relationships between heat treatment-microstructure, heat treatment-mechanical properties, and microstructure-mechanical properties were assessed.

  9. Spatial analysis of the tuberculosis treatment dropout, Buenos Aires, Argentina

    Science.gov (United States)

    Herrero, María Belén; Arrossi, Silvina; Ramos, Silvina; Braga, Jose Ueleres

    2015-01-01

    OBJECTIVE Identify spatial distribution patterns of the proportion of nonadherence to tuberculosis treatment and its associated factors. METHODS We conducted an ecological study based on secondary and primary data from municipalities of the metropolitan area of Buenos Aires, Argentina. An exploratory analysis of the characteristics of the area and the distributions of the cases included in the sample (proportion of nonadherence) was also carried out along with a multifactor analysis by linear regression. The variables related to the characteristics of the population, residences and families were analyzed. RESULTS Areas with higher proportion of the population without social security benefits (p = 0.007) and of households with unsatisfied basic needs had a higher risk of nonadherence (p = 0.032). In addition, the proportion of nonadherence was higher in areas with the highest proportion of households with no public transportation within 300 meters (p = 0.070). CONCLUSIONS We found a risk area for the nonadherence to treatment characterized by a population living in poverty, with precarious jobs and difficult access to public transportation. PMID:26270011

  10. Energy performance of air-to-water and water-to-water heat pumps in hotel applications

    International Nuclear Information System (INIS)

    We present work on measurement of the energy performance of heat pumps for hotel operations in subtropical climates. Two city hotels in Hong Kong were investigated. The first case was an application of an air-to-water heat pump to provide heating for an outdoor swimming pool during the heating season. The second case was the installation of three water-to-water heat pumps to complement an existing boiler system for hot water supply. The heating energy output and corresponding electricity use were measured. The heat pump energy efficiency was evaluated in terms of the coefficient of performance (COP), defined as the heating energy output to the electrical energy use. The air-to-water heat pump provided 49.1 MW h heating while consuming 24.6 MW h electricity during the 6((1)/(2))-month heating season from mid-October to April. For the water-to-water heat pumps, the estimated annual heating output and the electricity use were 952 and 544 MW h, respectively. It was found that the heat pumps generally operated in a COP range of 1.5-2.4, and the payback period was about two years, which was considered financially attractive

  11. Microstructure and mechanical properties of heat-resistant 12% Cr ferritic-martensitic steel EK-181 after thermomechanical treatment

    Science.gov (United States)

    Polekhina, N. A.; Litovchenko, I. Yu.; Tyumentsev, A. N.; Astafurova, E. G.; Chernov, V. M.; Leontyeva-Smirnova, M. V.

    2015-10-01

    The effect of high-temperature thermomechanical treatment (TMT) with the deformation in the austenitic region on the features of microstructure, phase transformations and mechanical properties of low-activation 12% Cr ferritic-martensitic steel EK-181 is investigated. It is established, that directly after thermomechanical treatment (without tempering) the sizes and density of V(CN) particles are comparable with those after a traditional heat treatment (air quenching and tempering at 720°C, 3 h), where these particles are formed only during tempering. It causes the increasing of the yield strength of the steel up to ≈1450 MPa at room temperature and up to ≈430 MPa at the test temperature T = 650°C. The potential of microstructure modification by this treatment aimed at improving heat resistance of steel is discussed.

  12. Comparative performance evaluation of cascaded air-source hydronic heat pumps

    International Nuclear Information System (INIS)

    Highlights: • Development of cascaded air-source hydronic heat pumps. • Analysis of single to multi-staged heat pumps through energy and exergy approaches. • Performance evaluations of these heat pump systems through energy and exergy efficiencies. • Comparative assessment of these for better applications. - Abstract: The results are reported of an investigation of the effects of cascading air-source heat pumps on performance for hydronic residential systems. Three heat pump systems are modeled as single-stage, single-refrigerant cascaded, and two-refrigerant cascaded. Energy and exergy analyses are performed, and a comparative performance analysis is carried out, considering energy efficiency, refrigerant mass flow rates, evaporator pressure, exergy efficiency, and several other criteria. Three sets of source and supply temperatures, representing different climates and different water sink systems (low, medium and high temperature), are used to provide more comprehensive behavior assessments of the systems. Additionally, the optimum intermediate pressure of the cascaded systems for all working temperature pairs is found for the highest energetic COP and exergetic COP. Compared to a single stage heat pump, cascading improves the overall energy efficiency of the system for low-ambient temperatures, but not for high-ambient temperatures. Although this improvement is minor, the exergetic COP is increased by 67% for the single refrigerant cascaded system and 70% for a two-refrigerant cascaded system, at low ambient temperatures. Using refrigerant R404A in the low-pressure cycle marginally improves the energetic COP of the cascaded heat pump, but increases the evaporator working pressure, making it possible to use smaller compressors. However, the overall refrigerant mass flow rates increase with cascading. The two cascaded systems have higher exergy destructions (by almost four times) compared to the single stage system, mainly due to having more components

  13. Implementation of the quantitative evaluation method of the tempering effect during heating and cooling processes in post weld heat treatment

    International Nuclear Information System (INIS)

    In order to evaluate the temper effect during the multiple post weld heat treatment (PWHT) process, Thermal Cycle Tempering Parameter (TCTP) proposed by the authors, which is derived by extending Larson-Miller parameter to non-isothermal process, has been used to evaluate quantitatively the temper effect during heating and cooling processes in the process of PWHT. It has been clarified that the temper effect in the multiple PWHT process including long-time heating and cooling processes can be quantitatively evaluated by TCTP. On the basis of the present study, it might be possible to shorten the holding time of the heat treatment for multiple PWHT. (author)

  14. Laminar-flow Liquid-to-air Heat Exchangers - Energy-efficient Display Cabinet Applications

    Energy Technology Data Exchange (ETDEWEB)

    Haglund Stignor, Caroline

    2009-02-15

    Provisions are stored and displayed in supermarkets and grocery stores, at a temperature lower than the ambient, in display cabinets, which are responsible for a significant amount of the energy use in this sector. During the 1990s, major changes in the regulations governing the use of synthetic refrigerants took place in Sweden. This resulted in many refrigeration systems being converted to systems with indirect cooling by means of a liquid secondary refrigerant. The cooling coil is an important component in a display cabinet and traditionally, different kinds of tube-coils, with aluminium fins on expanded circular copper tubes, have been used. Many secondary heat transfer media have relatively high viscosities at low temperatures, and so the flow regime is often laminar, which may lead to poor heat transfer. However, it is possible to achieve high heat transfer coefficients even for laminar flows if an appropriate design of the heat exchanger is applied. Flat-tube heat exchangers have been used for a long time in automotive applications, where compactness is important. The display cabinet application involves low air velocities in combination with condensation of water vapour, and sometimes even frosting, and is therefore different from other applications where flat-tube heat exchangers have been used earlier. The objective of this research work has been to find a suitable, more energy efficient, heat exchanger design for indirectly cooled display cabinets. An efficiency that would mean that temperature differences would be so small that frosting could be avoided was aimed for. This research work has sandwiched experimental investigations with theoretical modelling and parameter studies. Initially, the heat transfer and pressure drop performance of conventional cooling coils operating with liquid secondary refrigerants was studied in fullscale experiments. Thereafter, the liquid-side (or tube-side) heat transfer was studied experimentally in small

  15. Gas injection to inhibit migration during an in situ heat treatment process

    Science.gov (United States)

    Kuhlman, Myron Ira; Vinegar; Harold J.; Baker, Ralph Sterman; Heron, Goren

    2010-11-30

    Methods of treating a subsurface formation are described herein. Methods for treating a subsurface treatment area in a formation may include introducing a fluid into the formation from a plurality of wells offset from a treatment area of an in situ heat treatment process to inhibit outward migration of formation fluid from the in situ heat treatment process.

  16. Modernization and efficiency of heat treatment and heating up plants; Modernisierung und Effizienz von Thermoprozessanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, Peter [LOI Thermprocess GmbH, Essen (Germany); Kuehn, Friedhelm [Ingenieurbuero fuer Waermebehandlung, Industrieoefen und Energieberatung, Muelheim (Germany)

    2010-10-15

    A goal of this contribution is to show, using examples of the thermal heat treatment industry and the thermal processing units used there (Beltype plants, routary hearth, walking hearth, walking beam, pusher type furnaces and gas carburizing plants as well as case hardening plants), which increases in efficiency within and outside of the actual thermal treatment process and the necessary thermal processing units for the order are available today. From the possibilities of the reduction of energy employment resulting from that, a high potential for the discharge of the environment can be derived. The economic effect concerning energy employment and saving possibilities will also be considered. Concluding, examples of case-hardening show which variants of a change of process present themselves partially in the future, in order to achieve substantial production increases and thus energy cost reductions. (orig.)

  17. Air-water simulation of phenomena of corium dispersion in direct containment heating

    International Nuclear Information System (INIS)

    The present research at Purdue addresses the corium dispersion during the direct containment heating in reactor severe accident. The degree of corium dispersion has not only the strongest parametric effect on the containment pressurization but also has the highest uncertainty in predicting it. In view of this, a separate effect test program on the corium dispersion mechanisms in the reactor cavity and the subcompartment trapping mechanisms was initiated in spring of 1992 at Purdue under the direction of the Nuclear Regulatory Commission. Four major objectives of this corium dispersion study are: (1) to perform a detailed scaling study using the newly proposed step-by-step integral scaling method, then to evaluate existing models for entrainment, particle size and trapping, (2) to perform carefully designed simulation experiments using water-air and woods metal-air in a 1/10 linear scale model, (3) to develop reliable mechanistic models and correlations for corium dispersions, which can be used to predict corium jet disintegration, entrainment, drop size, liquid film carry over, and subcompartment trapping, and (4) to use the models to perform stand along calculations for typical prototypic conditions. The combination of water-air and woods metal-air as working fluid will give a unique data base over broad parametric ranges which can be used together with the integral test results to develop reliable models and correlations. The results of the experiments that were conducted using air-water are presented

  18. Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

    Science.gov (United States)

    Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

    2008-01-01

    NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

  19. Analyzing the possibility of constructing the air heating system for an integrated solid fuel gasification combined-cycle power plant

    Science.gov (United States)

    Mikula, V. A.; Ryzhkov, A. F.; Val'tsev, N. V.

    2015-11-01

    Combined-cycle power plants operating on solid fuel have presently been implemented only in demonstration projects. One of possible ways for improving such plants consists in making a shift to hybrid process circuits of integrated gasification combined-cycle plants with external firing of solid fuel. A high-temperature air heater serving to heat compressed air is a key element of the hybrid process circuit. The article describes application of a high-temperature recuperative metal air heater in the process circuit of an integrated gasification combined-cycle power plant (IGCC). The available experience with high-temperature air heating is considered, and possible air heater layout arrangements are analyzed along with domestically produced heat-resistant grades of steel suitable for manufacturing such air heater. An alternative (with respect to the traditional one) design is proposed, according to which solid fuel is fired in a noncooled furnace extension, followed by mixing the combustion products with recirculation gases, after which the mixture is fed to a convective air heater. The use of this design makes it possible to achieve considerably smaller capital outlays and operating costs. The data obtained from thermal and aerodynamic calculations of the high-temperature air heater with a thermal capacity of 258 MW for heating air to a temperature of up to 800°C for being used in the hybrid process circuit of a combined-cycle power plant are presented.

  20. A novel trapezoid fin pattern applicable for air-cooled heat sink

    Science.gov (United States)

    Chen, Chien-Hung; Wang, Chi-Chuan

    2015-11-01

    The present study proposed a novel step or trapezoid surface design applicable to air-cooled heat sink under cross flow condition. A total of five heat sinks were made and tested, and the corresponding fin patterns are (a) plate fin; (b) step fin (step 1/3, 3 steps); (c) 2-step fin (step 1/2, 2 steps); (d) trapezoid fin (trap 1/3, cutting 1/3 length from the rear end) and (e) trapezoid fin (trap 1/2, cutting 1/2 length from the rear end). The design is based on the heat transfer augmentation via (1) longer perimeter of entrance region and (2) larger effective temperature difference at the rear part of the heat sink. From the test results, it is found that either step or trapezoid design can provide a higher heat transfer conductance and a lower pressure drop at a specified frontal velocity. The effective conductance of trap 1/3 design exceeds that of plate surface by approximately 38 % at a frontal velocity of 5 m s-1 while retains a lower pressure drop of 20 % with its surface area being reduced by 20.6 %. For comparisons exploiting the overall thermal resistance versus pumping power, the resultant thermal resistance of the proposed trapezoid design 1/3, still reveals a 10 % lower thermal resistance than the plate fin surface at a specified pumping power.

  1. Experimental study of gas engine driven air to water heat pump in cooling mode

    International Nuclear Information System (INIS)

    Nowadays a sustainable development for more efficient use of energy and protection of the environment is of increasing importance. Gas engine heat pumps represent one of the most practicable solutions which offer high energy efficiency and environmentally friendly for heating and cooling applications. In this paper, the performance characteristics of gas engine driven heat pump used in water cooling were investigated experimentally without engine heat recovery. The effects of several important factors (evaporator water inlet temperature, evaporator water volume flow rate, ambient air temperature, and engine speed) on the performance of gas engine driven heat pump were studied in a wide range of operating conditions. The results showed that primary energy ratio of the system increased by 22.5% as evaporator water inlet temperature increased from 13 oC to 24 oC. On the other hand, varying of engine speed from 1300 rpm to 1750 rpm led to decrease in system primary energy ratio by 13%. Maximum primary energy ratio has been estimated with a value of two over a wide range of operating conditions.

  2. Mechanisms controlling the SST air-sea heat flux feedback and its dependence on spatial scale

    Science.gov (United States)

    Hausmann, Ute; Czaja, Arnaud; Marshall, John

    2016-05-01

    The turbulent air-sea heat flux feedback (α , in {W m}^{-2}{ K}^{-1} ) is a major contributor to setting the damping timescale of sea surface temperature (SST) anomalies. In this study we compare the spatial distribution and magnitude of α in the North Atlantic and the Southern Ocean, as estimated from the ERA-Interim reanalysis dataset. The comparison is rationalized in terms of an upper bound on the heat flux feedback, associated with "fast" atmospheric export of temperature and moisture anomalies away from the marine boundary layer, and a lower bound associated with "slow" export. It is found that regions of cold surface waters (≤ 10° C) are best described as approaching the slow export limit. This conclusion is not only valid at the synoptic scale resolved by the reanalysis data, but also on basin scales. In particular, it applies to the heat flux feedback acting as circumpolar SST anomaly scales are approached in the Southern Ocean, with feedbacks of ≤ 10 {W m}^{-2}{ K}^{-1} . In contrast, the magnitude of the heat flux feedback is close to that expected from the fast export limit over the Gulf Stream and its recirculation with values on the order of ≈40 {W m}^{-2}{ K}^{-1} . Further analysis suggests that this high value reflects a compensation between a moderate thermodynamic adjustment of the boundary layer, which tends to weaken the heat flux feedback, and an enhancement of the surface winds over warm SST anomalies, which tend to enhance the feedback.

  3. Energy Saving Potentials and Air Quality Benefits of Urban Heat Island Mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem

    2005-08-23

    Urban areas tend to have higher air temperatures than their rural surroundings as a result of gradual surface modifications that include replacing the natural vegetation with buildings and roads. The term ''Urban Heat Island'' describes this phenomenon. The surfaces of buildings and pavements absorb solar radiation and become extremely hot, which in turn warm the surrounding air. Cities that have been ''paved over'' do not receive the benefit of the natural cooling effect of vegetation. As the air temperature rises, so does the demand for air-conditioning (a/c). This leads to higher emissions from power plants, as well as increased smog formation as a result of warmer temperatures. In the United States, we have found that this increase in air temperature is responsible for 5-10% of urban peak electric demand for a/c use, and as much as 20% of population-weighted smog concentrations in urban areas. Simple ways to cool the cities are the use of reflective surfaces (rooftops and pavements) and planting of urban vegetation. On a large scale, the evapotranspiration from vegetation and increased reflection of incoming solar radiation by reflective surfaces will cool a community a few degrees in the summer. As an example, computer simulations for Los Angeles, CA show that resurfacing about two-third of the pavements and rooftops with reflective surfaces and planting three trees per house can cool down LA by an average of 2-3K. This reduction in air temperature will reduce urban smog exposure in the LA basin by roughly the same amount as removing the basin entire onroad vehicle exhaust. Heat island mitigation is an effective air pollution control strategy, more than paying for itself in cooling energy cost savings. We estimate that the cooling energy savings in U.S. from cool surfaces and shade trees, when fully implemented, is about $5 billion per year (about $100 per air-conditioned house).

  4. Air conditioning on turbo-generator input using waste heat of pyrolysis technology of solid domestic waste utilization

    OpenAIRE

    Ryzhkov, Serhiy S.; Markina, Liudmyla M.; Serbin, Serhii I.; Radchenko, Mykola I.

    2014-01-01

    The efficiency is studied of using waste heat of condensation of utilization technology of solid domestic waste by means of pyrolysis for air conditioning (cooling with drying) on the input of the turbo-generator which works at pyrolysis gas.

  5. Experimental evaluation of dry/wet air-cooled heat exchangers. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Hauser, S.G.; Gruel, R.L.; Huenefeld, J.C.; Eschbach, E.J.; Johnson, B.M.; Kreid, D.K.

    1982-08-01

    The ultimate goal of this project was to contribute to the development of improved cooling facilities for power plants. Specifically, the objective during FY-81 was to experimentally determine the thermal performance and operating characteristics of an air-cooled heat exchanger surface manufactured by the Unifin Company. The performance of the spiral-wound finned tube surface (Unifin) was compared with two inherently different platefin surfaces (one developed by the Trane Co. and the other developed by the HOETERV Institute) which were previously tested as a part of the same continuing program. Under dry operation the heat transfer per unit frontal area per unit inlet temperature difference (ITD) of the Unifin surface was 10% to 20% below that of the other two surfaces at low fan power levels. At high fan power levels, the performances of the Unifin and Trane surfaces were essentially the same, and 25% higher than the HOETERV surface. The design of the Unifin surface caused a significantly larger air-side pressure drop through the heat exchanger both in dry and deluge operation. Generally higher overall heat transfer coefficients were calculated for the Unifin surface under deluged operation. They ranged from 2.0 to 3.5 Btu/hr-ft/sup 2/-/sup 0/F as compared to less than 2.0 Btu hr-ft/sup 2/-/sup 0/F for the Trane and HOETERV surfaces under similar conditions. The heat transfer enhancement due to the evaporative cooling effect was also measureably higher with the Unifin surface as compared to the Trane surface. This can be primarily attributed to the better wetting characteristics of the Unifin surface. If the thermal performance of the surfaces are compared at equal face velocities, the Unifin surface is as much as 35% better. This method of comparison accounts for the wetting characteristics while neglecting the effect of pressure drop. Alternatively the surfaces when compared at equal pressure drop essentially the same thermal performance.

  6. Heat treatment process for improving ductility of Ti-25V-15Cr-2Al-0.2C alloy

    Institute of Scientific and Technical Information of China (English)

    LEI Li-ming(雷力明); HUANG Xu(黄旭); SUN Fu-sheng(孙福生); WU Xue-ren(吴学仁); CAO Chun-xiao(曹春晓); D Rugg; W Voice

    2003-01-01

    The effect of heat treatment and thermal exposure on the microstructure and mechanical properties of non-burning β titanium alloy Ti-25V-15Cr-2Al-0.2C (mass fraction, %) was investigated. It is found that the amount of α precipitation in samples after solution treatment followed by air cooling increases with increasing solution temperature. After solution treatment, the alloy was subjected to two different heat treatments to stabilize the material. The results show that the single ageing treatment(700 ℃, 4 h, AC) leads to a large amount of α precipitation, while the triplex treatment(850 ℃, 2 h, FC+700 ℃, 6 h, FC+540 ℃, 6 h, AC) significantly suppresses the formation of α precipitates. It is more important that after long-term exposure at 540 ℃(the expected application temperature) samples heat-treated by the triplex treatment have markedly higher ductility than those given the single aging treatment. The intermetallic compound TiCr2 is observed in samples after long-term exposure, which further degrades the ductility of the alloy.

  7. Numerical Simulation of Vacuum Heat Treatment Thermal Hysteresis Time of GH4169 Superalloy Workpiece

    Institute of Scientific and Technical Information of China (English)

    WANGMing-wei; ZHANGLi-wen; JIANGGuo-dong; ZHANGFan-yun; LiChen-hui; ZHANGLi-sheng; ZHANGZun-li

    2004-01-01

    A nonlinear finite element model of vacuum heat treatment process was developed. In this model, influence of many factors, such as nonlinear heat radiation, temperature-dependent thermal physical properties of material are considered. The temperature field of GH4169 alloy workpiece during vacuum heat treatment process was calculated using finite element software MSC.Marc, and the thermal hysteresis time of the workpiece was predicted. An experiment of vacuum heat treatment of GH4169 superalloy workpiece was carried out to verify the calculation. The experimental results of temperature profile agree well with the simulated results. This work lays a theoretical foundation for optimizing technical parameter of vacuum heat treatment process.

  8. New short T6 heat treatments for aluminium silicon alloys obtained by semisolid forming

    OpenAIRE

    Menargues Muñoz, Sergi; Martín Fuentes, Enrique; Baile Puig, Maria Teresa; Picas Barrachina, Josep Anton

    2014-01-01

    In this work the heat treatment response of SSM processed A356 and A357 casting alloys was analysed. The development of a new T6 heat treatment, with solution times less than 30 mm has been allowed. In this new short heat treatment, the alloy showed better mechanical properties compared to the same alloy which heat treated in standard conditions (solution time between 6 h and 8 h). This new heat treatment, carried out at the solution temperature of 540 degrees C, enabled the complete magnesiu...

  9. Evaluation of carbon diffusion in heat treatment of H13 tool steel under different atmospheric conditions

    OpenAIRE

    Maziar Ramezani; Timotius Pasang; Zhan Chen; Thomas Neitzert; Dominique Au

    2015-01-01

    Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of heat treatment experiments had been conducted under different atmospheric conditions and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat treatment without atmospheric contro...

  10. Heat transfer and friction factor characteristics of rectangular channel solar air heater duct having protrusions as roughness element

    OpenAIRE

    Maneesh Kaushal, Varun

    2012-01-01

    An experimental investigation has been carried out to see the effect of roughness element on heat transfer and friction factor on the absorber plate of the solar air heater. The roughness provided is in the form of protrusions which are arranged in an arc pattern. This paper presents an investigation to study the effect of protruded geometry on heat transfer coefficient and friction factor in an artificially roughened solar air heater duct. The pair of protrusion geometry arc angle (α) of 45o...

  11. Gas Engine-Driven Heat Pump Chiller for Air-Conditioning and Hot Water Supply Systems

    Science.gov (United States)

    Fujita, Toshihiko; Mita, Nobuhiro; Moriyama, Tadashi; Hoshino, Norimasa; Kimura, Yoshihisa

    In Part 1 of this study, the performance characteristics of a 457kW gas engine-driven heat pump (GHP) chiller have been obtained from a simulation model analysis for both cooling and heating modes and it has been found that the part-load characteristics of the GHP chiller are fairly well. On the back of Part 1, a computer simulation program has been developed for the evaluation of GHP chiller systems to compare with the other types of heat source systems for air-conditioning and hot water supply applications. The simulation program can be used to estimate annual energy consumption, annual CO2 emission, etc. of the systems with the data of monthly and hourly thermal loads on various buildings, outdoor air conditions, and characteristics of various components comprising the systems. By applying this to some cases of medium-scale hotel, office, shop, and hospital buildings, it has been found that the GHP chiller systems have advantages particularly in the cases of hotels and hospitals where a lot of hot water demand exists. It has also been found that the combination of a GHP chiller and a direct-fired absorption water chiller boiler (hot and chilled water generator) appears promising.

  12. Thermal decomposition of sugarcane straw, kinetics and heat of reaction in synthetic air.

    Science.gov (United States)

    Rueda-Ordóñez, Yesid Javier; Tannous, Katia

    2016-07-01

    The aim of this work was to analyze the thermal decomposition, kinetics and heat of reaction of sugarcane straw in synthetic air by thermogravimetry (TG) and differential scanning calorimetry (DSC). The TG and DSC experiments were carried out using heating rates of 2.5°C/min, 5°C/min, and 10°C/min, and particle diameter of 0.250mm. In the study of the smoldering reaction were identified three consecutive stages, drying, oxidative pyrolysis, and combustion. Thus, the kinetic pathway was composed by six independent parallel reactions, three for each stage after drying, in which the activation energies were 176, 313, 150, 80, 150, and 100kJ/mol. The heat of reaction in synthetic air was completely exothermic releasing 8MJ/kg. The modeled curves of thermal decomposition of sugarcane straw presented good agreement with experimental data. Then, the kinetic parameters obtained could be used to analyze different processes involving smoldering. PMID:27019126

  13. Sensible heat flux at the spray-laden air-sea interface

    Science.gov (United States)

    Richter, D. H.; Sullivan, P.

    2013-12-01

    Air-sea exchange processes are typically parameterized in large-scale numerical models owing to the prohibitively large length and time scales involved. For example, intensity predictions of tropical cyclones rely heavily on accurate knowledge of the fluxes of momentum, heat, and moisture from the ocean surface, but these quantities must be computed using bulk flux coefficients since small-scale exchange processes cannot be fully resolved. As a result, these exchange coefficients attempt to represent a large number of physical processes, whose individual roles are difficult to distinguish. One such near-surface process is the formation and transport of sea spray, which has been identified as a possible source of flux modification. In this study, we investigate the role of spray in the turbulent transfer of sensible heat at the air-sea interface using direct numerical simulation (DNS) and a Lagrangian point-particle tracking technique. This is a follow-up to our previous work where the influence of spray on the transfer of momentum was examined. Our idealized simulations suggest that sea spray has the ability to greatly enhance the transfer of sensible heat at the ocean surface, in agreement with existing sea spray models. The physical explanation of this behavior and a discussion of its apparent contradiction with observational studies will be included. Simulation snapshot showing particle-turbulence interaction

  14. Heat transfer and pressure drop for air-water mixtures in an isoflux vertical annulus

    Energy Technology Data Exchange (ETDEWEB)

    Khattab, M. [Nuclear Research Center, Cairo (Egypt); El-Sallak, M. [Cairo Univ. (Egypt); Morcos, S.M. [Cairo Univ. (Egypt); Salama, A. [Nuclear Research Center, Cairo (Egypt)

    1996-05-01

    Heat transfer and pressure drop in flows of air-water mixtures have been investigated experimentally in an isoflux vertical annulus. The superficial liquid Reynolds number, as a reference parameter, varied from 4500 to 30 000, at different values of gas-to-liquid superficial velocity ratios up to 20 and surface heat fluxes from 50 to 240 kW/m{sup 2}. Enhancement of the two-phase heat transfer coefficient is pronounced particularly at low liquid superficial velocities. The results are correlated and compared with some models of two-phase, two-component flows for air-water mixtures within their range of validity. Satisfactory agreement is obtained from the trend of the experimental data. (orig.) [Deutsch] Waermeuebertragung und Druckabfall in Stroemungen von Luft-Wasser-Gemischen wurden experimentell in einem vertikalen Ringraum untersucht. Der Referenzparameter, die Reynolds`sche Zahl an der Fluessigkeitsoberflaeche, variierte zwischen 4500 und 30 000, das Verhaeltnis der Oberflaechengeschwindigkeiten von Luft und Wasser erreichte Werte bis zu 20, und die Waermestromdichte an der Oberflaeche lag zwischen 50 und 240 kW/m{sup 2}. Der Zweiphasen-Waermeuebertragungskoeffizient nimmt bei kleinen Oberflaechengeschwindigkeiten besonders ausgepraegt zu. Die experimentellen Ergebnisse werden durch bestehende mathematische Modelle von Zweiphasen-Zweikomponenten-Stroemungen befriedigend vorhergesagt. (orig.)

  15. Preparation and investigation of aluminized coating and subsequent heat treatment on 9Cr–1Mo Grade 91 steel

    International Nuclear Information System (INIS)

    Highlights: • Hot dip aluminizing and heat treatment was carried out on 9Cr–1Mo Grade 91 steel. • Sample heat treated at 650 °C showed Fe2Al5 phase and at 750 °C showed Fe2Al5/FeAl. • Samples heat treated at 950 °C showed FeAl/α-Fe(Al). • The scratch test showed the best result with 950 °C/5 h + 750 °C/2 h sample. • α-Al2O3 and γ-Al2O3 were present on the surface of the samples treated at 950 °C. - Abstract: Iron aluminide inner coating with alumina top layer is being considered as a potential solution for tritium permeation barrier and mitigating MHD pressure drop for liquid metal blanket concepts in the fusion reactor systems. Hot-dip aluminizing with subsequent heat treatment seems to offer a good possibility to produce aluminized coating with alumina top layer. 9Cr–1Mo Grade 91 steel samples were hot dipped in Al melt containing 2.25 wt% of Si at 750 °C for 3 min. Heat treatment was performed at 650, 750 and 950 °C for 5 h; samples were either air cooled or furnace cooled. Coatings have been evaluated by SEM, EDX, X-ray diffraction, microhardness, scratch adhesion and Raman spectroscopy. The thickness of the layers and phases formed were influenced by the heat treatment adopted. Fe2Al5 was the major phase present in the samples heat treated at 650/750 °C, whereas FeAl and α-Fe(Al) primarily made up the outer and inner layers respectively in the samples heat treated at 950 °C. Cooling method deployed affected the hardness. Air cooled samples had comparatively higher hardness than furnace cooled samples. The scratch test showed the adhesion for the samples heat treated at 950 °C was much better as compared to the samples heat treated at 650/750 °C. Raman spectroscopy analysis showed the presence of both α-Al2O3 and γ-Al2O3 on the surface of the samples heat treated at 950 °C, while Fe3O4 was present in the furnace cooled sample only

  16. Hemodialysis Catheter Heat Transfer for Biofilm Prevention and Treatment.

    Science.gov (United States)

    Richardson, Ian P; Sturtevant, Rachael; Heung, Michael; Solomon, Michael J; Younger, John G; VanEpps, J Scott

    2016-01-01

    Central line-associated bloodstream infections (CLABSIs) are not easily treated, and many catheters (e.g., hemodialysis catheters) are not easily replaced. Biofilms (the source of infection) on catheter surfaces are notoriously difficult to eradicate. We have recently demonstrated that modest elevations of temperature lead to increased staphylococcal susceptibility to vancomycin and significantly soften the biofilm matrix. In this study, using a combination of microbiological, computational, and experimental studies, we demonstrate the efficacy, feasibility, and safety of using heat as an adjuvant treatment for infected hemodialysis catheters. Specifically, we show that treating with heat in the presence of antibiotics led to additive killing of Staphylococcus epidermidis with similar trends seen for Staphylococcus aureus and Klebsiella pneumoniae. The magnitude of temperature elevation required is relatively modest (45-50°C) and similar to that used as an adjuvant to traditional cancer therapy. Using a custom-designed benchtop model of a hemodialysis catheter, positioned with tip in the human vena cava as well as computational fluid dynamic simulations, we demonstrate that these temperature elevations are likely achievable in situ with minimal increased in overall blood temperature. PMID:26501916

  17. Development of automated system for superconductor heat treatment

    CERN Document Server

    Nakayama, S

    2002-01-01

    For the next generation accelerator magnets, use of A15 type compounds, especially use of Nb3Sn can be thought, because of their requirements to establish higher magnetic field. As Nb3Sn has high critical magnetic field and can be applied to magnets for high magnetic field, it did not reach to enough critical current property, yet. Authors already proposed some new methods such as distributed tin (DT) method, and so on, to advance further upgrading of current density to establish high current density without experience before today. On heat treatment of Nb3Sn superconductive cables, when treating their plural samples under different times and conditions, a problem was that every solids had to be repeated by the same elapsed changes from their beginning, to need considerable times and labors. To solve this problem, a method to simultaneously begin sintering of plural samples to sample every solids at every times elapsing a constant heat treating time, can be considered. Here was reported that a system effectiv...

  18. Moisture-heating Treatment and Processing Optimization of Parboiled Rice

    Institute of Scientific and Technical Information of China (English)

    ZhaoSiming; XiongShanbai

    2001-01-01

    Abstract: Effect of moisture-heating treatment on the quality ofparboiled rice and processing optimization were studied. Resultsindicated that the riboflavine content of parboiled rice is higher, and thecolor is light, aroma is strong and the head yield ratio is higher bysoaking with acid and ethanol, cooking at high-pressure and thendrying with high temperature-high moisture. Optimal processingparameters are soaking paddy with citrate acid for 2h, then with 1.5%ethanol for 1.5h, high pressure cooking for 30min, and then dryingunder 55%RH, 90~C for 30min, cooling slowly for 2.5h, and shelling andmilling immediately. Head yield ratio and whole rice ratio was 67.3%and 87.0% respectively, the color of finished product is light, ricearoma is strong, and the content of riboflavine is 2.47mg/100g.

  19. Moisture-heating Treatment and Processing Optimization of Parboiled Rice

    Institute of Scientific and Technical Information of China (English)

    Zhao Siming; Xiong Shanbai

    2001-01-01

    Effect of moisture-heating treatment on the quality of parboiled rice and processing optimization were studied. Results indicated that the riboflavine content of parboiled rice is higher, and the color is light, aroma is strong and the head yield ratio is higher by soaking with acid and ethanol, cooking at high-pressure and then drying with high temperature-high moisture. Optimal processing parameters are soaking paddy with citrate acid for 2h, then with 1.5% ethanol for 1.5h, high pressure cooking for 30min, and then drying under 55%RH, 90℃ for 30min, cooling slowly for 2.5h, and shelling and milling immediately. Head yield ratio and whole rice ratio was 67.3% and 87.0% respectively, the color of finished product is light, rice aroma is strong, and the content of riboflavine is 2.47mg/100g.

  20. Heat treatment and characterization of duplex 1010 and 1020 steels

    Energy Technology Data Exchange (ETDEWEB)

    Young, M.J.

    1977-11-01

    An investigation concerning the heat treatment of duplex ferritic-martensitic 1010 and 1020 steels has been carried out. Tensile and impact properties of intermediately quenched and continuously annealed specimens have been characterized and microstructural correlations established. The rule for two phase mixtures may be used as a fairly good approximation of the mechanical behavior of the duplex system, and improved correlations are possible with suitable modifications for the size, shape and distribution of the second phase. The property differentials between the duplex 1010 and 1020 at equal volume fractions of martensite are due mainly to the higher carbon content (hence, higher strength) of the 1020 martensite. Important metallurgical variables include subgrain formation, retained austenite, transformation twinning and martensite fraction. Of these, the volume fraction of martensite appears to be the most influential in controlling the strength, ductility and impact properties of the duplex systems studied.