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04130 Investigation of a directly coupled photovoltaic pumping system connected to a large absorber field
75
Environment
(pollution, health protection,
safety)
using the screw machines, leakage and friction effects had to be determined and simulated in order to assess the performance of the heat pump system. Numerical results of system tests are presented from cases where steamwater and ammonia were used as thermal fluids in place of normally used fluids such as halogenated chlorofluorocarbon, which has been implicated in the depletion of stratospheric ozone. Hydration heat of zeolites and application for heat 97104129 storage and heat pump Mizota, T. N&u Sokutei, 1997, 24, (2). 79-89. (In Japanese) Reviews research on hydration/dehydration-calorimetry of zeolites and on zeolite heat pump systems. Hydration heat of zeolites can be used for heat exchange in a heat pump system without any fuels or electricity. Reversible heat exchange or heat storage of the zeolitelwater system have been tested extensively so as to use zeolites as heat exchange absorbents and water as an absorbate. The combination of zeolite and water in the system is environmentally safe, and attractive for effective use of low temperature heat sources such as solar energy and waste heat from factories. However, hydration mechanisms of zeolitic water are so complicated that even in basic researches required to explore optimum zeolites suitable for the heat pump system, there exists some confusion. Investigation of a directly coupled photovoltaic 97104130 pumping system connected to a large absorber field Hilmer, F. et al. SolarEnergy,1997, 61, (2), 65-76. The paper studies the performance of a large absorber field for swimming pool heating with a PV-powered circulating pump (PV-absorber system). Several directly coupled and MPP tracked PV-pumping sub-systems were examined and their steady-state characteristics calculated. These characteristics were used to measure the useful thermal energy delivered by the combined PV-absorber system. The thermal performance of the MPP tracked PV-absorber system is virtually the same as that of a conventional system with a grid-connected circulating pump, for the climatic conditions of Marburg (Germany). Optimal performance of an endoreversible Carnot 97104131 heat pump Sun, F. et al. Energy Cowers. Mgmt, 1997,38, (14) 1439-1443. The optimal performance of an endoreversible Carnot heat pump under the condition of non-linear heat transfer with its surroundings is investigated. The relationship between the coefficient of performance (COP) and the heating load of the heat pump is derived. The result provides additional criteria for use in the study and performance evaluation of heat pumps. Performance and economic feasibility of ground 97104132 source heat pumps in cold climate Healy, P. F. and Ugursal V. I. Int. .I. Energy Res., 1997, 21, (lo), 857-870. Attractive alternatives to conventional heating and cooling systems are provided by ground source heat pumps (GSHP), owing to their higher energy utilization efficiency. In this paper, the effect of various system parameters on GSHP performance is studied using a computer model. Also, a comparative economic evaluation is carried out to assess the feasibility of using a GSHP in place of conventional heating/cooling systems and an air source heat pump. The results indicate that system parameters can have a significant effect on performance, and that GSHP is economically preferable to conventional systems. Tube and fln geometry alternatives for the design of 97104133 absorption-heat-pump heat exchangers Garimella, S. et al. Enhanced Heat Transfer, 1997, 4, (3). 217-235. Prospects for the use of highly compact, flat-tube multi-louver fin heat exchangers to replace conventional round-tube hydronic fluid-to-air heat exchangers for space-conditioning applications are evaluated. Heat exchangers of this type can benefit absorption space-conditioning systems. The performance of this new geometry is compared to conventional roundtube heat exchangers through the quantification of heat exchanger mass decrease for equivalent heat duties. Within the limitations of the available heat transfer and friction factor correlations, round-tube heat exchangers with flat, wavy, louvered and annular fins and flat-tube heat exchangers with multilouver fins were designed to meet typical absorption cycle design requirements. The effect of design variables on heat transfer performance and tube- and air-side pressure drops was investigated Flat-tube heat exchangers can transfer equivalent heat duties while meeting pressure drop constraints accompanied by a significant reduction in the overall mass and size.
15
ENVIRONMENT Pollution, Health Protection,
Safety
Activated carbons tailored to remove different 97104134 pollutants from gas streams and from solution EI-Nabarawy, T. H. et al. Adsorpt. Sci. Technol., 1997, 15, (I), 59-68. Maghara coal was used to prepare non-activated carbon, physio-activated carbons, zinc chloride-activated carbons, and potassium sulfide-activated carbons. The surface areas of these carbons were determined by investigating the adsorption of carbon dioxide at 298 K and of nitrogen at 77 K. The decolourization powers of the carbons were determined from methylene blue adsorption at 308 K. The adsorption of methanol, benzene, n-hexane, n-octane and n-pinene at 308 K was also determined using equilibrium and flow techniques. The removal of ammonia and phenol from water was investigated on some selected samples. The activated carbons showed high capacities towards the removal of organic pollutants from water and from gas streams via adsorption. Their capacity towards a particular pollutant depends on the method of activation and is related to the textural and/or the chemical of the carbon surface. Aerosol concentrations and their gradients near 97104135 urban areas determined by means of the LIDAR method Zielinski, T. and Zielinski, A. Proc. SPIE-Int. Sot. Opt. Eng., 1997, 3104, (Lidar Atmospheric Monitoring), 242-246. In the coastal zones of the southern Baltic Sea, the aerosol concentrations and their gradients above the sea surface were derived. The size distribution functions and concentrations of the aerosol particles were determined by means of the lidar method. The results confirmed that aerosol concentrations and their gradients were relatively high in autumn and winter when the winds blew from the shore. Coal burning heat production for city inhabitants during the colder months influences this phenomenon, since there is a substantial amount of pollution produced which is carried with the winds over the sea in the form of aerosols. For the winds from the open sea directions, the values of concentrations and gradients were substantially lower, despite greater wind velocity. 97104136 Aerosols and climate: anthropogenic emissions and trends for 50 years Wolf, M. E. C. and Hidy, G. M. J Geophysical Res., /Atmos./. 1997, 102, (DIO), 11113-11121. Covering the period 1990-2040, a global inventory has been prepared for anthropogenic particulate emissions into the troposphere. It provides estimates for both primary particulate emissions and secondary contributions from atmospheric chemical reactions. Using a conventional method, total world-wide anthropogenic emissions of particles < 10 /Im diameter were estimated at 345 Tg/yr, excluding secondary NOs- and organics. Airborne sulfate accounts for approximately 35% of the particles entering the troposphere, from oxidation of SOz emissions. Emissions world-wide are dominated by fossil fuel combustion, particularly coal, and biomass burning. These emissions are projected to grow by 1.5-2.1 times in 2040, largely from fossil fuel combustion. Present anthropogenic emissions appear to be a small fraction of emissions from natural sources. However, the man-derived component could become comparable to natural emissions by 2040. Increased haziness may enhance negative climate forcing both directly by increased radiative scattering and indirectly by modifying cloud albedo and cover, The forcing will be spatially non-uniform, superimposed on the forcing derived from greenhouse gases. Air toxics benchmarking tests on a 10 MW coal97lO4137 fired utility boiler simulator Evans, A. P. et al. Proc. ht. Tech. Conf. Coal Util. Fuel Syst., 1996, 21, 733743. A five-year project is currently underway, aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants from coal-fired electrical utility plants. Babcock & Wilcox is conducting the project. The development work is being carried out using B&W’s new 10 MW, Clean Environment Development Facility (CEDF) wherein air toxics emissions control strategies can be developed under controlled conditions, and with proven predictability to commercial systems. Tests conducted in the CEDF will provide high quality, repeatable, comparable data over a wide range of coal properties, operating conditions, and emissions control systems. Development work is currently focusing on the capture of mercury, fine particulate, and a variety of inorganic species, such as the acid gases hydrogen chloride and hydrogen fluoride. The results of air toxic benchmarking tests on the CEDF boiler are presented. Ambient and biological monitoring of exposure to 97104136 at a coking plant polycyclic aromatic hydrocarbons Pyy, L. et al Sci. Total Environ., 1997, 199, (1,2), 151-158. Between 1988 and 1994, exposure to polycyclic aromatic hydrocarbons (PAH) was measured in a Finnish coking plant. Hygienic measurements were performed and correlations between concentrations of airborne pyrene with concentrations of the pyrene metabolite, I-pyrenol. in urine
349
Fuel and Energy Abstracts
September
1997
Environment
(pollution, health protection,
safety)
using the screw machines, leakage and friction effects had to be determined and simulated in order to assess the performance of the heat pump system. Numerical results of system tests are presented from cases where steamwater and ammonia were used as thermal fluids in place of normally used fluids such as halogenated chlorofluorocarbon, which has been implicated in the depletion of stratospheric ozone. Hydration heat of zeolites and application for heat 97104129 storage and heat pump Mizota, T. N&u Sokutei, 1997, 24, (2). 79-89. (In Japanese) Reviews research on hydration/dehydration-calorimetry of zeolites and on zeolite heat pump systems. Hydration heat of zeolites can be used for heat exchange in a heat pump system without any fuels or electricity. Reversible heat exchange or heat storage of the zeolitelwater system have been tested extensively so as to use zeolites as heat exchange absorbents and water as an absorbate. The combination of zeolite and water in the system is environmentally safe, and attractive for effective use of low temperature heat sources such as solar energy and waste heat from factories. However, hydration mechanisms of zeolitic water are so complicated that even in basic researches required to explore optimum zeolites suitable for the heat pump system, there exists some confusion. Investigation of a directly coupled photovoltaic 97104130 pumping system connected to a large absorber field Hilmer, F. et al. SolarEnergy,1997, 61, (2), 65-76. The paper studies the performance of a large absorber field for swimming pool heating with a PV-powered circulating pump (PV-absorber system). Several directly coupled and MPP tracked PV-pumping sub-systems were examined and their steady-state characteristics calculated. These characteristics were used to measure the useful thermal energy delivered by the combined PV-absorber system. The thermal performance of the MPP tracked PV-absorber system is virtually the same as that of a conventional system with a grid-connected circulating pump, for the climatic conditions of Marburg (Germany). Optimal performance of an endoreversible Carnot 97104131 heat pump Sun, F. et al. Energy Cowers. Mgmt, 1997,38, (14) 1439-1443. The optimal performance of an endoreversible Carnot heat pump under the condition of non-linear heat transfer with its surroundings is investigated. The relationship between the coefficient of performance (COP) and the heating load of the heat pump is derived. The result provides additional criteria for use in the study and performance evaluation of heat pumps. Performance and economic feasibility of ground 97104132 source heat pumps in cold climate Healy, P. F. and Ugursal V. I. Int. .I. Energy Res., 1997, 21, (lo), 857-870. Attractive alternatives to conventional heating and cooling systems are provided by ground source heat pumps (GSHP), owing to their higher energy utilization efficiency. In this paper, the effect of various system parameters on GSHP performance is studied using a computer model. Also, a comparative economic evaluation is carried out to assess the feasibility of using a GSHP in place of conventional heating/cooling systems and an air source heat pump. The results indicate that system parameters can have a significant effect on performance, and that GSHP is economically preferable to conventional systems. Tube and fln geometry alternatives for the design of 97104133 absorption-heat-pump heat exchangers Garimella, S. et al. Enhanced Heat Transfer, 1997, 4, (3). 217-235. Prospects for the use of highly compact, flat-tube multi-louver fin heat exchangers to replace conventional round-tube hydronic fluid-to-air heat exchangers for space-conditioning applications are evaluated. Heat exchangers of this type can benefit absorption space-conditioning systems. The performance of this new geometry is compared to conventional roundtube heat exchangers through the quantification of heat exchanger mass decrease for equivalent heat duties. Within the limitations of the available heat transfer and friction factor correlations, round-tube heat exchangers with flat, wavy, louvered and annular fins and flat-tube heat exchangers with multilouver fins were designed to meet typical absorption cycle design requirements. The effect of design variables on heat transfer performance and tube- and air-side pressure drops was investigated Flat-tube heat exchangers can transfer equivalent heat duties while meeting pressure drop constraints accompanied by a significant reduction in the overall mass and size.
15
ENVIRONMENT Pollution, Health Protection,
Safety
Activated carbons tailored to remove different 97104134 pollutants from gas streams and from solution EI-Nabarawy, T. H. et al. Adsorpt. Sci. Technol., 1997, 15, (I), 59-68. Maghara coal was used to prepare non-activated carbon, physio-activated carbons, zinc chloride-activated carbons, and potassium sulfide-activated carbons. The surface areas of these carbons were determined by investigating the adsorption of carbon dioxide at 298 K and of nitrogen at 77 K. The decolourization powers of the carbons were determined from methylene blue adsorption at 308 K. The adsorption of methanol, benzene, n-hexane, n-octane and n-pinene at 308 K was also determined using equilibrium and flow techniques. The removal of ammonia and phenol from water was investigated on some selected samples. The activated carbons showed high capacities towards the removal of organic pollutants from water and from gas streams via adsorption. Their capacity towards a particular pollutant depends on the method of activation and is related to the textural and/or the chemical of the carbon surface. Aerosol concentrations and their gradients near 97104135 urban areas determined by means of the LIDAR method Zielinski, T. and Zielinski, A. Proc. SPIE-Int. Sot. Opt. Eng., 1997, 3104, (Lidar Atmospheric Monitoring), 242-246. In the coastal zones of the southern Baltic Sea, the aerosol concentrations and their gradients above the sea surface were derived. The size distribution functions and concentrations of the aerosol particles were determined by means of the lidar method. The results confirmed that aerosol concentrations and their gradients were relatively high in autumn and winter when the winds blew from the shore. Coal burning heat production for city inhabitants during the colder months influences this phenomenon, since there is a substantial amount of pollution produced which is carried with the winds over the sea in the form of aerosols. For the winds from the open sea directions, the values of concentrations and gradients were substantially lower, despite greater wind velocity. 97104136 Aerosols and climate: anthropogenic emissions and trends for 50 years Wolf, M. E. C. and Hidy, G. M. J Geophysical Res., /Atmos./. 1997, 102, (DIO), 11113-11121. Covering the period 1990-2040, a global inventory has been prepared for anthropogenic particulate emissions into the troposphere. It provides estimates for both primary particulate emissions and secondary contributions from atmospheric chemical reactions. Using a conventional method, total world-wide anthropogenic emissions of particles < 10 /Im diameter were estimated at 345 Tg/yr, excluding secondary NOs- and organics. Airborne sulfate accounts for approximately 35% of the particles entering the troposphere, from oxidation of SOz emissions. Emissions world-wide are dominated by fossil fuel combustion, particularly coal, and biomass burning. These emissions are projected to grow by 1.5-2.1 times in 2040, largely from fossil fuel combustion. Present anthropogenic emissions appear to be a small fraction of emissions from natural sources. However, the man-derived component could become comparable to natural emissions by 2040. Increased haziness may enhance negative climate forcing both directly by increased radiative scattering and indirectly by modifying cloud albedo and cover, The forcing will be spatially non-uniform, superimposed on the forcing derived from greenhouse gases. Air toxics benchmarking tests on a 10 MW coal97lO4137 fired utility boiler simulator Evans, A. P. et al. Proc. ht. Tech. Conf. Coal Util. Fuel Syst., 1996, 21, 733743. A five-year project is currently underway, aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants from coal-fired electrical utility plants. Babcock & Wilcox is conducting the project. The development work is being carried out using B&W’s new 10 MW, Clean Environment Development Facility (CEDF) wherein air toxics emissions control strategies can be developed under controlled conditions, and with proven predictability to commercial systems. Tests conducted in the CEDF will provide high quality, repeatable, comparable data over a wide range of coal properties, operating conditions, and emissions control systems. Development work is currently focusing on the capture of mercury, fine particulate, and a variety of inorganic species, such as the acid gases hydrogen chloride and hydrogen fluoride. The results of air toxic benchmarking tests on the CEDF boiler are presented. Ambient and biological monitoring of exposure to 97104136 at a coking plant polycyclic aromatic hydrocarbons Pyy, L. et al Sci. Total Environ., 1997, 199, (1,2), 151-158. Between 1988 and 1994, exposure to polycyclic aromatic hydrocarbons (PAH) was measured in a Finnish coking plant. Hygienic measurements were performed and correlations between concentrations of airborne pyrene with concentrations of the pyrene metabolite, I-pyrenol. in urine
349
Fuel and Energy Abstracts
September
1997