15 Environment (pollution, health protection, safety)

96lO4166 Ventilation requirements in non-domestic buildings and energy efficiency Wouters, P. et al. Energy and Buildings, 1998, 27, (3). 257-261. The importance of the level of ventilation requirements on the energy demand of non-domestic buildings is examined. A tremendous difference is presently observed in the ventilation requirements in various countries as well as at the European level. Variations by a factor of 10 of the ventilation rate requirement can be found in the proposal for European standard CEN (European Committee for Standardization) prENV 1752 depending on the ‘cleanness’ of the building. The present paper develops these problems and makes a comparison with the situation in other areas like thermal comfort and lighting requirements. Results of a practical case study are included.

14 HEAT PUMPS

96lO4169 Exergy analysis and optimization of a solar-assisted heat pump Torres Reyes, E. et al. Energy, 1998, 23, (4), 337-344. The paper presents a theoretical and experimental exergy analysis of a solar-assisted heat pump for air heating. An experimental prototype that operates as a solar-assisted or as a conventional heat pump was tested to determine exergetic efficiency, total system irreversibility and component irreversibilities. A methodology for determination of the optimum temperature of the working fluid in the evaporation and condensation steps is proposed. The methodology is based on maximization of efficiency in these two parts of the system.

96lQ4170 Improved energy efficiency in absorption heat pump through process modification. Part I: solvents for liquid-liquid extraction of ammonia-water mixture Olawale, A. S. and Adefila, S. S. Energy Convers. Mgrnl, 1998, 39, (IO), 1015-1025. As a feasible replacement for the non-isothermal separation process employed in the conventional ammonia-water absorption heat pump, the isothermal liquid-liquid extraction process has been proposed in an attempt to improve the energy efficiency of the heat pump system. Of the two possible extraction schemes (based on which component of aqua ammonia is extracted), the ammonia-extracted scheme was found more suitable on the basis of availability of extract solvents whose use engender relatively lower energy consumption and loss. The relevant thermodynamic data was evaluated with UNIQUAC, while capacity and selectivity diagrams were used to select appropriate extract solvents for separation of the ammonia- water mixture. Nitrobenzene, toluene, m-xylene, ethylbenzene and styrene were found to be suitable solvents in the extraction process.

98lO4171 Improved energy efficiency in absorption heat pump through process modification. Part II: thermodynamic potential of liquid-liquid extraction of ammonia-water mixtures Olawale, A. S. and Adefila, S. S. Energy Convers. Mgmt, 1998, 39, (lo), 1053-1071. As an energy-efficiency improvement strategy for the conventional ammonia-water absorption heat pump, extraction-system-attached (ESA) ammonia-water absorption heat pumps were derived from the conventional system. The ESA absorption heat pumps were obtained by attaching a liquid-liquid extraction unit in the conventional system. Theoretical thermodynamic simulation of the ESA and conventional ammonia-water absorption heat pumps showed that a higher COP and less irreversibility occur when the ammonia-water mixture is separated by the liquid extraction process instead of the non-isothermal process used in the conventional system. The ESA systems employing nitrobenzene as the extraction solvent gave the highest COP and the lowest irreversibility.

99104172 Use of multi-stage cascades to improve perfor- mance of thermoelectric heat pumps Lindler, H. W. Energy Cowers. Mgml, 1998, 39, (lo), 1009-1014. As a miniature solid state device, small amounts of heat are pumped by a thermoelectric heat pump. Potential uses range from the cooling of electronic components to dorm size refrigerators. At the US Naval Academy an ongoing study proposes to use a miniature thermoelectric heat pump to maintain a neutron dosimeter at near constant temperatures in order to obtain more accurate readings. However, with increasing temperature difference, the coefficient of performance of the heat pump rapidly decreases. The potential improvement in heat pump performance from cascading two or more heat pumps in series operation is investigated by the study.

15 ENVIRONMENT

Pollution, Health Protection, Safety

98/04173 Abatement of air pollution in thermal processes for sewage sludge disposal Nethe, L. P. Ber. Wasserguete Abfailwirlsch., Tech. Univ. Muenchen, 1998, 137, 391-407. (In German) Sewage sludge incineration and co-combustion in municipal refuse incineration plants, coal power stations and cement manufacturing, together with incinerator flue gas cleaning with broad band adsorbents Sorbalit, is reviewed. Process scheme and operational examples are provided.

gal041 74 Analysis of polynuclear aromatic hydrocarbons from coal fly ash Purushothama, S. et al. Fuel Process. Technol., 1998, 53, (3), 235-242. This work aims to compare various extraction and quantification techniques for the determination of adsorbed polynuclear aromatic hydrocarbons (PAHs) on coal ash. Using three solvents, three methods and three GC/MS programmes, aliquots of a ‘clean’ fly ash from coal combustion doped with four PAHs have been extracted. The solvent which exerts the greatest primary effect is CH2CIZ. Highest recoveries were obtained using the reflux slurry extraction procedure with CH2C12 and a relatively fast (ZO”C/min) temperature ramp to 310°C. Ultrasonic assisted extraction affords the best repeatability with both CHzCl2 and toluene solvents.

gal041 75 Analysis of possibilities for separation of a suspen- sion of coke dust in water in a sedimentation process Bandrowski, J. et al. Karbo-Energochem.-Ekol., 1997, 42, (ll), 363-367. (In Polish) The paper studies the separation of coke dust suspension. The sedimenta- tion process is affected by the properties of the suspensions. The sedimentation tests of coke dust suspension in water was performed in order to calculate the sedimentation curve.

98/04176 Analysis of the factors influencing the removal of oil from used automotive oil filters during recycling operations Roberts, D. E. II and Peaslee, K. D. Resources Conservation and Recycling, 1998, 22, (l/2), 97-113. From the more than 425 million used oil filters (UOFs) discarded annually in the United States, an estimated 67,500 m3 (17.8 million gallons) of used oil could leach from landfills and pollute soil and water. The Environmental Protection Agency (EPA) has mandated that non-terne-plated used oil filters which have been gravity hot drained for at least 12 h are considered non-hazardous and acceptable for landfilling. It is required that filters be either punctured in the dome end, punctured in the anti-siphon valve or crushed before draining to meet the requirements for this EPA exemption. This paper evaluates the factors which affect the removal of used oil from UOFs by gravity hot-draining and crushing. These include oil temperature and viscosity, dome-end puncturing, draining orientation, filter design, time and crushing force. Of these factors, oil temperature, puncturing of the dome end, filter orientation and filter design were found to have a significant impact on oil removal by gravity draining. Orientation is very important because an oil filter drained to EPA’s recommendations still contains a significant quantity of oil which has a high probability of draining because of normal changes in the orientation of a filter during transport or placement in a landfill. Oil removal was significantly affected during crushing by oil temperature, filter design, and crushing force.

98l04177 Apparatus for collection of dust from dust-contain- ing gases Hayashi, T. and Asada, Y. Jpn. Kokai Tokkyo Koho JP 10 66,818 [98 66,818] (Cl. BOlD50/00), 10 Mar 1998, Appl. 96/240,975, 26 Aug 1996,4 pp. (In Japanese) A cyclone for separating and collecting dust, a spray device for spraying cyclone-passed fine liquid drops with adhered dust and a mist catcher for coagulating the fine liquid drops to form coarse liquid drops comprise the apparatus. The mist catcher is formed from wire meshes having thickness SO.1 and width 0.5 mm. The apparatus is suitable for collection of Incineration- and fly ashes from gases, etc.

98l04178 Application of solid-phase adsorption (SPA) to monitoring evolution of biomass tar from different types of gasiflers Brage, C. er al. Biomass Gasif. Pyrolysis, [Conf], 1997, 218-227. Edited by Kaltschmitt, M. and Bridgwater, A. V., CPL Press, Newbury, UK. A recently developed method for intermittent tar sampling and subsequent analysis is both fast and highly efficient. The method is based on SPA on silica bonded amino phase in combination with capillary gas chromato- graphy and flame ionization detection. The intended target analytes are phenolic and aromatic compqunds ranging in molecular masses from 78 (benzene) to 300 (coronene). The method displays major advantages over

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