- Email: [email protected]
03933 Application of combined heat-and-power and absorption cooling in a supermarket
13
Space heating and cooling
Processes for the injection of pulverized coal into 99103923 the blast furnace Letzel, D. et al. Stahl Eisen, 1998, 118, (12) 91-99. (In German) Five pulverized coal of different grain size were investigated to study their combustion behaviour. Grain size had no effect on the degree of burn of soft brown coal grades, whereas the burn-off of hard coal grades showed a strong dependence on it. The levels of volatile components and the carbon/ oxygen ratio of the coal grades have emerged as characteristic parameters. A combustion model was used to calculate the further combustion process of the char left over from the injected media in the raceway. If the hot blast temperature was increased, a stronger effect was achieved than enriching the blast with oxygen. Also determined was the effect of the Fe0 content on the ability to obtain a complete gasification of the pulverized coal.
Propagation of the internal pressure as swelling 99163924 pressure on the walls of coke ovens Arendt, P. et al. Glueckauf-Forschungsh., 1999, 60, (l), 19-23. (In German) Operated by DMT, the two semi-industrial coking ovens were used to investigate two different methods for the transfer of the internal gas pressure, which arises in the plastic zone, as swelling pressure acting on the oven chamber walls. High internal gas pressures of several hundred millibar are transmitted to the chamber wall almost on a 1:1 basis. As the chamber width increases there is a reduction in both the internal gas pressure and in the wall pressure, presumably as a result of the larger absolute shrinkage factor. At low internal gas pressure values, such as are produced by lower coking temperatures, only part of the pressure is transferred to the chamber wall as swelling pressure. In this case the relationships are more complex, with the result that without individual testing no generally applicable quantitative data is available on the relationship which exists between the internal gas pressure and the wall pressure as a function of temperature conditions, chamber width and the bulk density and type of the coal charge. However, since the application of low to medium swelling pressures are particularly relevant for industrial purposes, it is precisely this pressure range which is in need of a more detailed investigation.
99163925
Recent activities In research of ironmaklng
Itaya, H. Kawasaki Seilefsu Giho, 1999, 31, (1), l-7. (In Japanese) A brief overview is provided regarding recent ironmaking technologies in Japan. In addition, ironmaking R & D activities over the past decade are presented. Cost reduction and stable operation has been achieved in all areas of coke making, sintering, blast furnace and new smelting. In coke making, the contributions to the use of a large amount of low-cost semi-soft coal and the decrease in the trouble of hard push were brought about through coal blending technologies. In the field of sintering, fundamental studies on sinter reaction based on new experimental methods such as Xray CT and also a newly developed charging apparatus of raw material contributed to cost reduction. Furthermore, a new charging system of the furnace top, burden distribution control technology and computer simulation system for blast furnace operation have been developed for blast furnace technologies. These developments have realized a stable operation and also the large amount use of low cost burden and fuel. In the area of smelting reduction, a commercial plant of STAR process for stainless steel dust recycling has commenced operation and the application of this process to electric arc furnace dust recycling is under development.
Use of an oxygen-gas burner In a cupola for 99163926 processing of foundry dust and for replaclng energy Neumann, F. et al. Slevarenstvi, 1998, 46, (7/8), 253-258. (In Czech) Air Products, in co-operation with the firm Buderus Guss, has developed the process described here, of which the most important part is the oxygen burner. On the basis of a burner combusting coal dust developed in the 1980s this burner was developed for the present use. The present generation of burners represents considerable improvement. Besides residual matter such as cupola dust, industrial refuse, dust from a fettling shop and dust from the moulding equipment charged into the cupola by the burner, alloying agents such as ferrosilicon and ferromanganese and blown coal can be added so that the chemical composition of the melt is suitably controlled.
Uslng of coal fines in gasification-smeltlng unit in 99103927 manufacture of molten pig Iron or steel foreproduct Schrey, G. and Zahedi, P. PCT Int. Appl. WO 99 01,583 (Cl. C2lBl3/00), 14 Jan 1999, AT Appl. 9,7/1,157, 4 Jul 1997, 20 pp. (In German) During the production of molten pig iron or steel foreproduct from, especially, partly reduced iron sponge, a carbonaceous material consisting at least partly of coal fines and dust is supplied to a bed of the carbonaceous material to melt down the partly reduced iron sponge with simultaneous formation of a reduction gas. The used coal fines and coal dust are dried and mixed in the warm state with bitumen and then briquetted in the cold state. The produced briquettes are introduced to the gasification-smelting unit in the cold state and subjected to shock heating.
412
Fuel and Energy Abstracts
November 1999
12 REFRACTORIES/ CERAMICS Properties,
Production,
Applications
Causes of fracture of refractory lining in the upper zone of coking chambers
99103926
Krivoshein, V. T. Koks Khim., 1998, (lo), 19-21. (In Russian) The design of the coking furnaces influences the destruction of the Dinas refractory linings at the upper zone coking chambers. Principally, it is the height of the coking furnaces, as well as the mechanical effects of the thermal compression. Several recommendations are given to prevent the early failure of the refractory linings of coking furnaces. 99103929
Dynamically compacted all-ceramic lithium-ion
batteries
Jak, M. J. G. et al. J. Power Sources, 1999, 80, (112). 83-89. A cell design and a unique manufacturing process for all solid-state lithiumion batteries are reported. Detailed analyses of the manufacturing of the components for such a battery and the compaction of the green battery are presented. The electrodes were made of coatings of LiMnZ.04 on metal foils. The electrolyte was a free-standing foil of the ceramtc electrolyte lithium-doped BP04 in a polymer matrix. The different layers were wound and compacted by using magnetic pulse compaction. Several characteristics of the compacted batteries are presented.
Effect of the TiOn-fraction on the glass-ceramic crystallization In the system CaO-A1203-Si02
99103930
He, L. P. et al. Interceram., 1998, 47, (6), 387-389. The effect of the addition of the nucleating agent Ti02 on the crystallization of a glass-ceramic in the system CaO-AlzOs-Si02 was investigated by Xray diffraction, DTA and SEM. A suitable addition (fraction) of TiOz promoted the crystallization by the formation of an intermediate crystal phase which provided more favourable conditions for crystallization. Inadequate addition of TiOz limited the crystallization on the surface of the glass-ceramics, while a too large amount led to the formation of microcracks. The optimum fraction of TiOz was 10 mass%.
Results of use of the first large-unit coke oven batteries made of refractory concretes
99103931
Kombarov, A. P. et al. Koks Khim., 1998, (ll-12), 13-17. (In Russian) Details from the development and functional characteristics of refractory concrete linings in coke ovens in Russia are reported.
Self-firing carbon-based refractory linings with low porosity for blast furnace and reduced electric furnace
99103932
Hao, Y. et al. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,114,297 (Cl. C04B35/66), 3 Jan 1996, Appl. 94,106,611, 30 Jun 1994, 5 pp. (In Chinese) Composed of fired anthracite (preferably 35-60 wt%), Sic (IO-25 wt%), SiOa (O-15 wt%), ultrafine additives (3-20 wt%), coal pitch (O-25 wt%), coal tar (O-10 wt%) and resin (O-15 wt%), the refractory linings are described. The components are mixed and kneaded at llO-165°C and subsequently moulded in a precision finishing mould under high-pressure and high-frequency vibration. The ultrafine additives are silicon, B& and BN with <0.074 mm particle size.
13
SPACE HEATING COOLING
AND
Application of combined heat-and-power and absorption cooling in a supermarket
99103933
Maidment, G. G. et al. Applied Energy, 1999, 63, (3), 169-190. In recent years, it has become standard practice to consider Combined Heat-and-Power (CHP) systems for commercial buildings. CHP schemes are used because they are an efficient means of power generation. Unlike conventional power stations, they produce electricity locally and thus minimize the distribution losses, however, they also utilize the waste heat from the generation process. In applications where there is a combined heating and electricity requirement, a very efficient means of energy production is achieved compared to the conventional methods of providing heating and electricity. With new initiatives from the UK government on reduced energy-use, energy-efficient systems such as CHP have been considered for new applications. This paper summarizes the results of an investigation into the viability of CHP systems in supermarkets. The viability of conventional CHP has been theoretically investigated using a mathematical model of a typical supermarket. This has demonstrated that a
13
conventional CHP system may be practically applied. It has also been shown that compared to the traditional supermarket design, the proposed CHP system will use slightly less primary energy and the running costs will be significantly reduced. An attractive payback period of approximately 4 years has been calculated. Despite these advantages a considerable quantity of heat is rejected to atmosphere with this system and this is because the configuration utilizes the heat mainly for space heating which is only required for part of the year. To increase the utilization time, a novel CHP/ absorption system has been investigated. This configuration provides a continuous demand for the waste heat, which is used to drive an absorption chiller that refrigerates propylene glycol to -10°C for cooling the chilledfood cabinets. The results show this concept to be theoretically practical. The system has also been shown to be extremely efficient, with primary energy savings of approximately 20%, when compared to traditional supermarket designs and this would result in significant revenue cost savings as well as environmental benefits. Based upon these savings, a payback period for this system of approximately five years has been demonstrated.
Space
heating
and cooling
temperature (SET) within one scale error of thermal sensation. Small air movement with the radiant cooling system had a possibility of improving the comfortable sensation votes in the radiant cooling.
Energy and peak power savings potentlai of radiant cooling systems in US commercial buildings
99103938
Stetiu, C. Energy and Buildings, 1999, 30, (2). 127-138. Developed to estimate the energy and peak power savings potential of radiant cooling systems in commercial buildings in the USA, a parametric study is presented in this work. The study is based on the numerical modelling of a radiant cooling system and an all-air system at different locations in the USA. The results show that a building eauiDoed with a radiant cooling system can be operated in any US climate \;ith ‘low risk of condensation. For the office space examined in the study, employing a radiant cooling system instead of a traditional all-air system can save on average 30% of the energy consumption and 27% of the peak power demand due to space conditioning. The savings potential is climatedependent, and is larger in retrofitted buildings than in new construction.
Enhancement of convective heat transfer in rlbroughened rectangular ducts
99103934
99103939
In recent years. eiector refrigeration svstems have attracted manv research activities. ?hese sistems tra&tionally dperate with water as refrigerant with low COP values. Other refrigerants commonly used in mechanical vapour compression cycles may provide better performance for ejector refrigeration cycles. Eleven refrigerants, including water, halocarbon compounds (CFCs, HCFCs and HFCs), a cyclic organic compound and an azeotrope, were chosen as working fluids in an ejector refrigeration system and their performances compared. The results show that steam jet systems have very low COP values, the system using R152a as refrigerant has better performance and the variation in COP values for various refrigerants is almost independent of system operating conditions.
SundCn, B. Enhanced Heat Transfer, 1999, 6, (2-4), 89-103. In many engineering applications, enhancement of forced convection is important. Surface modifications like rib-roughening are commonly used in applications such as compact heat exchangers and cooling systems in gasturbine systems. Flow fields, friction factors and local and average heat transfer coefficients in rib-roughened ducts of the type appearyng are considered, here. Both experimental and numerical investigations are discussed. Details of the flow pattern and the influence of rib configuration, rib angle, rib pitch and rib height are discussed and physical interpretation of the results are provided. Some general conclusions are provided but it is also found that accurate numerical modelling of the flow and heat transfer from ribbed surfaces is difficult. Suggestions for further research are given.
Comparative study of the performance of an ejector refrigeration cycle operating with various refrigerants Sun,D.-W. Ener# Convers. Manage., 1999, 40, (S), 873-884.
Enhancement of heat transfer by turbulent decavina -~ --#~ swirl flaw
99103940
Dehumidifying chilled radiator system for hot and humid climates
99103935
Hirayama, Y. and Batty, W. J. Energy and Buildings, 1999, 30, (2), 203210. The paper investigates the application of room radiators for the purposes of cooling and dehumidification in buildings for hot and humid climates. The radiator is purposely brought below the dew point temperature of the room air thereby creating condensation on the radiator surface. The condensate is then collected at the base of the radiator and removed. A mathematical model describing the heat transfer regime within a room when this system is used has been verified using climate chamber tests. Results show the importance of the radiant transfer component for thermal comfort and suggests that more emphasis should be placed on this aspect during design. Furthermore, the possibilities for the chilled radiator system as an alternative to convdntional air conditioning systems by pa&ally or fully matching the sensible and latent component of the radiator output to the load requirements of a building is discussed. Since the temperature difference between the air and the radiator surface is small in this cooling application, larger surface areas are required than usual for the heating application. However, it means that the hot water temperature can be reduced for the heating mode. This allows the use of heat pumps to provide both hot and cold water at higher coefficients of performance than normally achievable. 99103936 Economic viability of cooling ceiling systems Sodec, F. Energy and Buildings, 1999, 30, (2), 195-201. Applying the numerical simulation program TRNSYS, the energy costs of a VAV system and a cooling ceiling system have been compared. The initial costs and the space requirements for the plants have also been collated. The cooling ceiling system was combined by the mechanical ventilation for the supply of outside air rate. Several parameters were varied to determine their influence on costs. A cooling ceiling system incurs lower energy costs and space requirements than VAV systems. Concerning the initial costs there is a break even point at a specific cooling load of 45-55 W m-*. At higher cooling loads, the first costs of a cooling ceiling system are more favourable.
Effect of humidity and small air movement on thermal comfort under a radiant cooling ceiling by subjective experiments
99103937
Kitagawa, K. et al. Energy and Buildings, 1999, 30, (2), 185-193. In comparison to the more frequently used convective air conditioning systems, radiant air-conditioning is expected to be more comfortable and have superior energy-savings. The objective of this study is to investigate the thermal comfort of local parts of the body and the whole body, in particular, including the effects of humidity and small air movements, by subjective experiments under a radiant cooling system. The experiments have been performed by using radiant cooling panels in a climate chamber. Subjects were seated on a chair under the radiant cooling panels, and voted their thermal sensation and comfortable sensation. The following results were obtained. Even in the radiant cooling system, the influence of humidity and small air movement on thermal sensation votes of the whole body could be correctly estimated by using a standard new effective
~G.
-
Yilmaz, M. et al. Energy Comers. Manage., 1999, 40, (13). 1365-1376. An experimental investigation was carried out on the heat transfer and friction characteristics of a decaying swirl flow. The swirling motion of the air was uroduced bv a radial euide vane swirl eenerator. The vanes of the swirl geherator we;e designeYd to be adjustable to obtain different swirl intensities. Different guide vane angles were used for the swirling flow experiments. The results were correlated in the form of Nusselt number as a function of Reynolds number, Prandtl number and the vane angle as Nu = 0.133Re”.h5Pr”.4(1 + tan )” 4”h. An augmentation of up to 98% in Nusselt number was obtained in the decaying swirl flow depending upon the Reynolds number and the vane angle. It was found that the performance of swirling flow is higher than corresponding axial flow with high vane angles and relatively low Reynolds numbers. 99103941 Estimation and measurement of electric energy consumption due to air conditioning cooling load Al-Rabghi, 0. M. et al. Energy Comers. Manage., 1999, 40, (14). 15271542. Due to air conditioning in buildings, electric energy consumption is tremendous. esoeciallv in nlaces havine hot humid weather. such as Jeddah. Saudi Arabia. ‘Building simulation pr&rammes, such as DOE2, are ve; valuable tools for studying building energy consumption under different conditions. These programmes can be used to investigate the effect of different building designs on their energy consumption. This paper presents the experimental and theoretical variations of electric power consumed by an air conditioning system. For the experimental part, a building has been chosen, and different sensors were installed to measure and record electric kW consumption at different indoor and outdoor conditions. In the theoretical part, the Visual DOE simulation programme, which is based on the well known DOE2E programme, has been used. Actual building data was fed to the programme to generate the instantaneous electric consumption due to air conditioning cooling load. Comparison between measured and predicted electric consumptions is presented.
Experimental analysis of a condenser heat recovery in an air condittoning plant
99103942
Schibuola, L. Energy, 1999, 24, (4), 273-283. The performance of a total heat recovery system was analysed by monitoring building-plant system long-term behaviour. Some of the installed chillers offer the possibility of a total recovery of the heat rejected by condenser. The results are very satisfactory both in energy and economic-financial terms. The experimental test takes advantage of the supervisor just existing in the building. Therefore it is an example of how these control systems can be used not only for safety and management needs, but also for a detailed performance analysis able to permit an easy simulation of the effects of different design and control options.
An experimental study of multiple parameter switching control for radiant floor heating systems
99103943
Cho, S.-H. and Zaheer-uddin, M. Energy, 1999, 24, (5), 433-444. Consisting of two identical 3 x 4.4 x 3.8 m3 rooms, an experimental facility was built; each room has a gas-fired boiler supplying hot water to the radiant-floor heating system. An electrically heated storage tank installed in
Fuel and Energy Abstracts
November 1999 413
Space heating and cooling
Processes for the injection of pulverized coal into 99103923 the blast furnace Letzel, D. et al. Stahl Eisen, 1998, 118, (12) 91-99. (In German) Five pulverized coal of different grain size were investigated to study their combustion behaviour. Grain size had no effect on the degree of burn of soft brown coal grades, whereas the burn-off of hard coal grades showed a strong dependence on it. The levels of volatile components and the carbon/ oxygen ratio of the coal grades have emerged as characteristic parameters. A combustion model was used to calculate the further combustion process of the char left over from the injected media in the raceway. If the hot blast temperature was increased, a stronger effect was achieved than enriching the blast with oxygen. Also determined was the effect of the Fe0 content on the ability to obtain a complete gasification of the pulverized coal.
Propagation of the internal pressure as swelling 99163924 pressure on the walls of coke ovens Arendt, P. et al. Glueckauf-Forschungsh., 1999, 60, (l), 19-23. (In German) Operated by DMT, the two semi-industrial coking ovens were used to investigate two different methods for the transfer of the internal gas pressure, which arises in the plastic zone, as swelling pressure acting on the oven chamber walls. High internal gas pressures of several hundred millibar are transmitted to the chamber wall almost on a 1:1 basis. As the chamber width increases there is a reduction in both the internal gas pressure and in the wall pressure, presumably as a result of the larger absolute shrinkage factor. At low internal gas pressure values, such as are produced by lower coking temperatures, only part of the pressure is transferred to the chamber wall as swelling pressure. In this case the relationships are more complex, with the result that without individual testing no generally applicable quantitative data is available on the relationship which exists between the internal gas pressure and the wall pressure as a function of temperature conditions, chamber width and the bulk density and type of the coal charge. However, since the application of low to medium swelling pressures are particularly relevant for industrial purposes, it is precisely this pressure range which is in need of a more detailed investigation.
99163925
Recent activities In research of ironmaklng
Itaya, H. Kawasaki Seilefsu Giho, 1999, 31, (1), l-7. (In Japanese) A brief overview is provided regarding recent ironmaking technologies in Japan. In addition, ironmaking R & D activities over the past decade are presented. Cost reduction and stable operation has been achieved in all areas of coke making, sintering, blast furnace and new smelting. In coke making, the contributions to the use of a large amount of low-cost semi-soft coal and the decrease in the trouble of hard push were brought about through coal blending technologies. In the field of sintering, fundamental studies on sinter reaction based on new experimental methods such as Xray CT and also a newly developed charging apparatus of raw material contributed to cost reduction. Furthermore, a new charging system of the furnace top, burden distribution control technology and computer simulation system for blast furnace operation have been developed for blast furnace technologies. These developments have realized a stable operation and also the large amount use of low cost burden and fuel. In the area of smelting reduction, a commercial plant of STAR process for stainless steel dust recycling has commenced operation and the application of this process to electric arc furnace dust recycling is under development.
Use of an oxygen-gas burner In a cupola for 99163926 processing of foundry dust and for replaclng energy Neumann, F. et al. Slevarenstvi, 1998, 46, (7/8), 253-258. (In Czech) Air Products, in co-operation with the firm Buderus Guss, has developed the process described here, of which the most important part is the oxygen burner. On the basis of a burner combusting coal dust developed in the 1980s this burner was developed for the present use. The present generation of burners represents considerable improvement. Besides residual matter such as cupola dust, industrial refuse, dust from a fettling shop and dust from the moulding equipment charged into the cupola by the burner, alloying agents such as ferrosilicon and ferromanganese and blown coal can be added so that the chemical composition of the melt is suitably controlled.
Uslng of coal fines in gasification-smeltlng unit in 99103927 manufacture of molten pig Iron or steel foreproduct Schrey, G. and Zahedi, P. PCT Int. Appl. WO 99 01,583 (Cl. C2lBl3/00), 14 Jan 1999, AT Appl. 9,7/1,157, 4 Jul 1997, 20 pp. (In German) During the production of molten pig iron or steel foreproduct from, especially, partly reduced iron sponge, a carbonaceous material consisting at least partly of coal fines and dust is supplied to a bed of the carbonaceous material to melt down the partly reduced iron sponge with simultaneous formation of a reduction gas. The used coal fines and coal dust are dried and mixed in the warm state with bitumen and then briquetted in the cold state. The produced briquettes are introduced to the gasification-smelting unit in the cold state and subjected to shock heating.
412
Fuel and Energy Abstracts
November 1999
12 REFRACTORIES/ CERAMICS Properties,
Production,
Applications
Causes of fracture of refractory lining in the upper zone of coking chambers
99103926
Krivoshein, V. T. Koks Khim., 1998, (lo), 19-21. (In Russian) The design of the coking furnaces influences the destruction of the Dinas refractory linings at the upper zone coking chambers. Principally, it is the height of the coking furnaces, as well as the mechanical effects of the thermal compression. Several recommendations are given to prevent the early failure of the refractory linings of coking furnaces. 99103929
Dynamically compacted all-ceramic lithium-ion
batteries
Jak, M. J. G. et al. J. Power Sources, 1999, 80, (112). 83-89. A cell design and a unique manufacturing process for all solid-state lithiumion batteries are reported. Detailed analyses of the manufacturing of the components for such a battery and the compaction of the green battery are presented. The electrodes were made of coatings of LiMnZ.04 on metal foils. The electrolyte was a free-standing foil of the ceramtc electrolyte lithium-doped BP04 in a polymer matrix. The different layers were wound and compacted by using magnetic pulse compaction. Several characteristics of the compacted batteries are presented.
Effect of the TiOn-fraction on the glass-ceramic crystallization In the system CaO-A1203-Si02
99103930
He, L. P. et al. Interceram., 1998, 47, (6), 387-389. The effect of the addition of the nucleating agent Ti02 on the crystallization of a glass-ceramic in the system CaO-AlzOs-Si02 was investigated by Xray diffraction, DTA and SEM. A suitable addition (fraction) of TiOz promoted the crystallization by the formation of an intermediate crystal phase which provided more favourable conditions for crystallization. Inadequate addition of TiOz limited the crystallization on the surface of the glass-ceramics, while a too large amount led to the formation of microcracks. The optimum fraction of TiOz was 10 mass%.
Results of use of the first large-unit coke oven batteries made of refractory concretes
99103931
Kombarov, A. P. et al. Koks Khim., 1998, (ll-12), 13-17. (In Russian) Details from the development and functional characteristics of refractory concrete linings in coke ovens in Russia are reported.
Self-firing carbon-based refractory linings with low porosity for blast furnace and reduced electric furnace
99103932
Hao, Y. et al. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,114,297 (Cl. C04B35/66), 3 Jan 1996, Appl. 94,106,611, 30 Jun 1994, 5 pp. (In Chinese) Composed of fired anthracite (preferably 35-60 wt%), Sic (IO-25 wt%), SiOa (O-15 wt%), ultrafine additives (3-20 wt%), coal pitch (O-25 wt%), coal tar (O-10 wt%) and resin (O-15 wt%), the refractory linings are described. The components are mixed and kneaded at llO-165°C and subsequently moulded in a precision finishing mould under high-pressure and high-frequency vibration. The ultrafine additives are silicon, B& and BN with <0.074 mm particle size.
13
SPACE HEATING COOLING
AND
Application of combined heat-and-power and absorption cooling in a supermarket
99103933
Maidment, G. G. et al. Applied Energy, 1999, 63, (3), 169-190. In recent years, it has become standard practice to consider Combined Heat-and-Power (CHP) systems for commercial buildings. CHP schemes are used because they are an efficient means of power generation. Unlike conventional power stations, they produce electricity locally and thus minimize the distribution losses, however, they also utilize the waste heat from the generation process. In applications where there is a combined heating and electricity requirement, a very efficient means of energy production is achieved compared to the conventional methods of providing heating and electricity. With new initiatives from the UK government on reduced energy-use, energy-efficient systems such as CHP have been considered for new applications. This paper summarizes the results of an investigation into the viability of CHP systems in supermarkets. The viability of conventional CHP has been theoretically investigated using a mathematical model of a typical supermarket. This has demonstrated that a
13
conventional CHP system may be practically applied. It has also been shown that compared to the traditional supermarket design, the proposed CHP system will use slightly less primary energy and the running costs will be significantly reduced. An attractive payback period of approximately 4 years has been calculated. Despite these advantages a considerable quantity of heat is rejected to atmosphere with this system and this is because the configuration utilizes the heat mainly for space heating which is only required for part of the year. To increase the utilization time, a novel CHP/ absorption system has been investigated. This configuration provides a continuous demand for the waste heat, which is used to drive an absorption chiller that refrigerates propylene glycol to -10°C for cooling the chilledfood cabinets. The results show this concept to be theoretically practical. The system has also been shown to be extremely efficient, with primary energy savings of approximately 20%, when compared to traditional supermarket designs and this would result in significant revenue cost savings as well as environmental benefits. Based upon these savings, a payback period for this system of approximately five years has been demonstrated.
Space
heating
and cooling
temperature (SET) within one scale error of thermal sensation. Small air movement with the radiant cooling system had a possibility of improving the comfortable sensation votes in the radiant cooling.
Energy and peak power savings potentlai of radiant cooling systems in US commercial buildings
99103938
Stetiu, C. Energy and Buildings, 1999, 30, (2). 127-138. Developed to estimate the energy and peak power savings potential of radiant cooling systems in commercial buildings in the USA, a parametric study is presented in this work. The study is based on the numerical modelling of a radiant cooling system and an all-air system at different locations in the USA. The results show that a building eauiDoed with a radiant cooling system can be operated in any US climate \;ith ‘low risk of condensation. For the office space examined in the study, employing a radiant cooling system instead of a traditional all-air system can save on average 30% of the energy consumption and 27% of the peak power demand due to space conditioning. The savings potential is climatedependent, and is larger in retrofitted buildings than in new construction.
Enhancement of convective heat transfer in rlbroughened rectangular ducts
99103934
99103939
In recent years. eiector refrigeration svstems have attracted manv research activities. ?hese sistems tra&tionally dperate with water as refrigerant with low COP values. Other refrigerants commonly used in mechanical vapour compression cycles may provide better performance for ejector refrigeration cycles. Eleven refrigerants, including water, halocarbon compounds (CFCs, HCFCs and HFCs), a cyclic organic compound and an azeotrope, were chosen as working fluids in an ejector refrigeration system and their performances compared. The results show that steam jet systems have very low COP values, the system using R152a as refrigerant has better performance and the variation in COP values for various refrigerants is almost independent of system operating conditions.
SundCn, B. Enhanced Heat Transfer, 1999, 6, (2-4), 89-103. In many engineering applications, enhancement of forced convection is important. Surface modifications like rib-roughening are commonly used in applications such as compact heat exchangers and cooling systems in gasturbine systems. Flow fields, friction factors and local and average heat transfer coefficients in rib-roughened ducts of the type appearyng are considered, here. Both experimental and numerical investigations are discussed. Details of the flow pattern and the influence of rib configuration, rib angle, rib pitch and rib height are discussed and physical interpretation of the results are provided. Some general conclusions are provided but it is also found that accurate numerical modelling of the flow and heat transfer from ribbed surfaces is difficult. Suggestions for further research are given.
Comparative study of the performance of an ejector refrigeration cycle operating with various refrigerants Sun,D.-W. Ener# Convers. Manage., 1999, 40, (S), 873-884.
Enhancement of heat transfer by turbulent decavina -~ --#~ swirl flaw
99103940
Dehumidifying chilled radiator system for hot and humid climates
99103935
Hirayama, Y. and Batty, W. J. Energy and Buildings, 1999, 30, (2), 203210. The paper investigates the application of room radiators for the purposes of cooling and dehumidification in buildings for hot and humid climates. The radiator is purposely brought below the dew point temperature of the room air thereby creating condensation on the radiator surface. The condensate is then collected at the base of the radiator and removed. A mathematical model describing the heat transfer regime within a room when this system is used has been verified using climate chamber tests. Results show the importance of the radiant transfer component for thermal comfort and suggests that more emphasis should be placed on this aspect during design. Furthermore, the possibilities for the chilled radiator system as an alternative to convdntional air conditioning systems by pa&ally or fully matching the sensible and latent component of the radiator output to the load requirements of a building is discussed. Since the temperature difference between the air and the radiator surface is small in this cooling application, larger surface areas are required than usual for the heating application. However, it means that the hot water temperature can be reduced for the heating mode. This allows the use of heat pumps to provide both hot and cold water at higher coefficients of performance than normally achievable. 99103936 Economic viability of cooling ceiling systems Sodec, F. Energy and Buildings, 1999, 30, (2), 195-201. Applying the numerical simulation program TRNSYS, the energy costs of a VAV system and a cooling ceiling system have been compared. The initial costs and the space requirements for the plants have also been collated. The cooling ceiling system was combined by the mechanical ventilation for the supply of outside air rate. Several parameters were varied to determine their influence on costs. A cooling ceiling system incurs lower energy costs and space requirements than VAV systems. Concerning the initial costs there is a break even point at a specific cooling load of 45-55 W m-*. At higher cooling loads, the first costs of a cooling ceiling system are more favourable.
Effect of humidity and small air movement on thermal comfort under a radiant cooling ceiling by subjective experiments
99103937
Kitagawa, K. et al. Energy and Buildings, 1999, 30, (2), 185-193. In comparison to the more frequently used convective air conditioning systems, radiant air-conditioning is expected to be more comfortable and have superior energy-savings. The objective of this study is to investigate the thermal comfort of local parts of the body and the whole body, in particular, including the effects of humidity and small air movements, by subjective experiments under a radiant cooling system. The experiments have been performed by using radiant cooling panels in a climate chamber. Subjects were seated on a chair under the radiant cooling panels, and voted their thermal sensation and comfortable sensation. The following results were obtained. Even in the radiant cooling system, the influence of humidity and small air movement on thermal sensation votes of the whole body could be correctly estimated by using a standard new effective
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Yilmaz, M. et al. Energy Comers. Manage., 1999, 40, (13). 1365-1376. An experimental investigation was carried out on the heat transfer and friction characteristics of a decaying swirl flow. The swirling motion of the air was uroduced bv a radial euide vane swirl eenerator. The vanes of the swirl geherator we;e designeYd to be adjustable to obtain different swirl intensities. Different guide vane angles were used for the swirling flow experiments. The results were correlated in the form of Nusselt number as a function of Reynolds number, Prandtl number and the vane angle as Nu = 0.133Re”.h5Pr”.4(1 + tan )” 4”h. An augmentation of up to 98% in Nusselt number was obtained in the decaying swirl flow depending upon the Reynolds number and the vane angle. It was found that the performance of swirling flow is higher than corresponding axial flow with high vane angles and relatively low Reynolds numbers. 99103941 Estimation and measurement of electric energy consumption due to air conditioning cooling load Al-Rabghi, 0. M. et al. Energy Comers. Manage., 1999, 40, (14). 15271542. Due to air conditioning in buildings, electric energy consumption is tremendous. esoeciallv in nlaces havine hot humid weather. such as Jeddah. Saudi Arabia. ‘Building simulation pr&rammes, such as DOE2, are ve; valuable tools for studying building energy consumption under different conditions. These programmes can be used to investigate the effect of different building designs on their energy consumption. This paper presents the experimental and theoretical variations of electric power consumed by an air conditioning system. For the experimental part, a building has been chosen, and different sensors were installed to measure and record electric kW consumption at different indoor and outdoor conditions. In the theoretical part, the Visual DOE simulation programme, which is based on the well known DOE2E programme, has been used. Actual building data was fed to the programme to generate the instantaneous electric consumption due to air conditioning cooling load. Comparison between measured and predicted electric consumptions is presented.
Experimental analysis of a condenser heat recovery in an air condittoning plant
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Schibuola, L. Energy, 1999, 24, (4), 273-283. The performance of a total heat recovery system was analysed by monitoring building-plant system long-term behaviour. Some of the installed chillers offer the possibility of a total recovery of the heat rejected by condenser. The results are very satisfactory both in energy and economic-financial terms. The experimental test takes advantage of the supervisor just existing in the building. Therefore it is an example of how these control systems can be used not only for safety and management needs, but also for a detailed performance analysis able to permit an easy simulation of the effects of different design and control options.
An experimental study of multiple parameter switching control for radiant floor heating systems
99103943
Cho, S.-H. and Zaheer-uddin, M. Energy, 1999, 24, (5), 433-444. Consisting of two identical 3 x 4.4 x 3.8 m3 rooms, an experimental facility was built; each room has a gas-fired boiler supplying hot water to the radiant-floor heating system. An electrically heated storage tank installed in
Fuel and Energy Abstracts
November 1999 413