07 Alternative energy sources (solar energy)

integrated gasification/gas turbine technology, which offers high-energy conversion efficiencies. The electricity is produced by direct combus- tion of biomass, advanced direct combustion, gasification, and pyrolysis technologies, which are almost ready for commercial scale use. The major research and developments of the biomass power industry are focusing on gasifier scale-up, system analysis, and site-specific commercial feasibility studies.

03/00696 Thermal behavior of biomass plant materials Meszaros, E. et 01. Chrmia I Itzrlwier-ia Ekologicznu, 2002, 9. (I), 33-41. TG-mass spectrometry was applied to detect the characteristics of a special poplar wood that was improved for energetic purposes. The thermal decomposition of the sapwood and the heartwood as well as the bark and the whole sample were studied. The effect of inorganic materials in the wood has also been studied. All samples were milled to a particle size smaller than 120 llrn and heated at lo-40”/min in an inert Ar atmosphere and in an oxidative (Ar:O = 79:21) atmosphere. Some samples were pretreated by washing with 60” Hz0 for 2 h to remove inorganic substances from the wood.

03/00697 Utilization of urban and pulping wastes to produce synthetic fuel via pyrolysis Demirbas, A. f%rrg13 Soz/~c~c.\, 2002. 24. (3), 205-213. Major byproducts of delignification processes of lignocellulosic biomass include lignin degradation products. Lignin and its degra- dation products have fuel values. The yields of liquid and gaseous products from the solid waste pyrolysis increased from 23.8 to 49.7% with increasing temperatures at 584-683 K. The yields of liquid and gaseous products from the black liquor pyrolysis increased from 7.3 to 55.0% with increasing temperatures at 500-800 K. The yields of liquid and gaseous products from pyrolysis of the solid waste and black liquor samples increased with increasing temperature. This increase is very sharp for the yields of liquid products from the solid waste at the same temperature range.

Geothermal energy

03/00698 Adventures in the life of a small geothermal district heating project or ‘the little project that could’ Merrick, D. Fusion Engineering and Design, 2002, 23, (3), l-5. A small community drilled a 2100-ft geothermal well to use the geothermal water for district heating. Pump test results showed a long- term production rate of 37 gpm at approximately 190EF with a pump set at 250 feet. The method of disposal is to the surface waters of a river after flowing though an activated charcoal filter to remove mercury. This paper chronicles the three-year evolution of a small geothermal direct-use project from conception to the final stages of challenges that were faced by a small community.

water Ilow rate inside the condenser and the compressor input frequency on the GHPS operation. Experiments are done on a small- scale GHPS at the water flow rate ranging from 0.054 kg/s to 0.174 kg/s and the frequency from 30 to 55 Hz. The analysis of the experimental data reveals the relationships among the compressor frequency, the water flow rate and other important parameters such as coefficient of performance (COP), heat capacity and compressor ,power input. The conclusions in the paper can serve BS some guidance to the load adjustment of GHPS.

03/00701 Numerical analysis of erosion of the rotor labyrinth seal in a geothermal turbine Mazur, Z. rt al. Geothermics, 2002. 3 I. (5). 563 577 Excessive erosion of the labyrinth seal of a 110 MW geothermal turbine has been investigated. This study used computational fluid dynamics (CFD) and aims to identify one cause of erosion and a possible solution for substantially reducing it. The predictions were based upon a numerical calculation using a CFD model of the labyrinth seal with a water/steam flow containing hard solid particles and solved with a commercial CFD code: Fluent V5.0. The results3 confirmed the existence of flow conditions that play a major role in the rotor labyrinth seal erosion. Afterwards, the flow path w,.ts simulated with changes of rotor labyrinth seal geometry, which are Indeed feasible of being implemented. The results confirmed that it is possible to reduce the erosion process by approximately 80% by incorporating a steam flow deflector in the fourth stage diaphragm, which changes the steam flow direction in the inlet zone to the rotor labyrinth seal channel, resulting in a reduction in steam volumetric mass flow and hard particle velocity by about 44%.

03/00702 Simulation of the effect of scale deposition on a geothermal turbine Kubiak, J. A. and Urquiza-beltrAn, G. (;c,c,tllc,r./lrrt’.\, 2002, 31, (5), 545- 562. Dissolved chemicals contained in geothermal steam can lead to corrosion, erosion and deposition of scale on turbine blades, reducing their useful life. In addition, deposits on the blading system reduce the flow area of the turbine. The first-stage nozzle group is typically most affected by deposition of scale although scale may be present in other parts of the system. The most common deposits .lre of silica and calcium carbonate. This decreases the output capacit!r,and efficiency of the turbine. This paper presents the results of simulations on the effect of scale deposition in the first-stage nozzle group on the steam pressure before and after the first stage, output capacity and efficiency of the turbine. By measuring the steam pressure before and after the first stage the change in the flow area can be estimated. A method of monitoring the percentage of nozzle plugging in real time is proposed. The method can be applied to any turbine that is susceptible to scale deposition.

03/00703 Turkey’s geothermal energy potential Demirbay, A. Energ Sources, 2002, 24, (I 2). 1107 -1 11 15. Turkey is one of the seven geothermal-potential rich countries in the world: More than 1000 hot and mineral water springs (up to 373 and 413 K) in geothermal fields with a temperature range of 313 to 505 K have been discovered in Turkey. Geothermal energy is clean, inexpensive, renewable, and can be utilized in various forms, such as space heating and domestic hot water supply, (‘02 and dry-ice production processes, heat pumps, greenhouse heating, swimming and balneology (therapeutic baths), industrial processes, and electricity generation. Since 1990, space heating and greenhouse developments have exhibited significant progress. The overall grothcrmal potential of Turkey is about 3X000 MW.

03/00699 Geothermal energy: power for a sustainable future Kaygusuz, K. and Kaygusuz, A. EIICI.SI, Sourtrs, 2002, 24, (IO). 937 947. This paper discusses the potential and utilization of geothermal energy in Turkey. Geothermal energy for electricity generation has been produced commercially since 1913, and for four decades on the scale of hundreds of MW both for electricity generation and direct use. Utilization has increased rapidly during the last three decades. In 2000, geothermal resources were identified in over 80 countries, and there are quantified records of geothermal utilization in 58 countries in the world. The worldwide use of geothermal energy amounts to 49 TWhi vear of electricity and 53 TWh/year for direct use. On the other hand, -Turkey is one of the countries with significant potential in geothermal energy. Resource assessments have been made many times by the Mineral Research and Exploration Directorate (MTA) of Turkey. The main uses of geothermal energy are mostly moderate and low temperature applications such as space heating and domestic hot water supply, greenhouse heating, industrial processes, heat pumps, and electricity generation. The data accumulated since 1962 show that the estimated geothermal power and direct use potential are about 4500 MWe and 31500 MWt, respectively. Present applications have shown that geothermal energy in Turkey and other countries is clean and much cheaper compared to the other fossil and renewable energy sources.

Solar energy

03/00704 A comprehensive procedure for performance evaluation of solar food dryers Augustus Leon, M. et al. Renewable and Su,\talrluhlr Energ?, Reviews, 2002, 6. (4), 367-393. Solar food dryers are available in a range of size and design and are used for drying various food products. Testing a dryer is necessary to evaluate its absolute and comparative performance with other dryers and the test results provide relevant information for the designer as well as the user. Literature reviews on existing testing prozedures reveal that a comprehensive procedure for evaluating the performance of solar food dryers is not available. Therefore, selection of dryers for a particular application is largely a decision based on what is available and the types of dryers currently used widely. This paper presents a detailed review of parameters generally used in testing and evaluation of different types of solar food dryers. The inadequacies of the

03/00700 Influence of two systematic parameters on the geothermal heat pump system operation Zhao, L. et al. Renewable Energy, 2003, 28, (l), 35-43. In order to match the output capacity of a geothermal heat pump system (GHPS) with the actual load requirement, research has been carried out in finding the influence of two systematic parameters. the

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