Performance Analysis on a Hot Dry Rock Geothermal Resource Power Generation System Based on Kalina Cycle

Significance Statement

 Hot dry rock, as an environmental friendly and almost inexhaustible new energy buried under the ground, is a kind of underexplored low temperature resource. The thermal energy reserves of hot dry rock in the earth are huge. Studies have shown that it contains nearly 10 billion quarts of thermal energy even in shallow hot dry rock area. It is significant to actively promote the development and utilization of hot dry rock resource. Kalina cycle can achieve a higher power output from a specified geothermal heat source when compared with organic Rankine cycle. The ammonia-water mixture is used as the working fluid in Kalina cycle, which can result in a better heat transfer matching relations in medium or low temperature source applications. It seems a very reasonable idea for application of Kalina cycle in hot dry rock power generation system.

In this paper, a hot dry rock power generation system model based on conventional Kalina cycle is recommended. Through thermodynamics analysis, the system performances are analyzed theoretically.

We believe that this model can give us better understanding of hot dry rock power generation system based on Kalina cycle, and one of guidelines to improve the power generation system efficiency.

 

About The Author

Gaosheng Wei is a associate professor in the School of Energy, Power and Mechanical Engineering at the North China Electric Power University, China. He received his PhD degree in Thermal Engineering in 2006 from University of Science and Technology Beijing.

His research is focused on energy and water conservation technology in thermal power unit, Micro/nano Heat transfer theory, thermophysical properties of materials and measurement technology, and heat energy storage technology, etc. He has published more than 50 articles in journals and more than 10 articles in proceedings of international conferences. He is also author of 5 patent certificates. 

Journal Reference

Energy Procedia, Volume 75, 2015, Pages 937–945.

Gaosheng Wei, , Jie Meng, Xiaoze Du, Yongping Yang

School of Energy, Power and Mechanical Engineering, Key Laboratory of Condition Monitoring and Control for Power Plant Equipment of Ministry of Education, North China Electric Power University, Beijing, China, 102206

Abstract

Based on the conventional Kalina cycle, a hot dry rock geothermal resource power generation system is recommended in this paper. To predict the system performance, the corresponding thermal calculation model is established. A high pressure condenser and a low pressure condenser are used to condense the working fluid (Ammonia-water mixture) and the basic fluid in the recommended system, respectively, and a regenerator is adopted to recover part of exhaust heat of the turbine, at the same time to provide energy for the separation of ammonia-water mixture. The parameter performance analyses are carried out on the system. Results show that both the thermal efficiency and dynamic power recovery increase with elevation of heat source temperature, the dynamic recovery efficiency varies in the range of 8.5-18 percent, in the heat source temperature range of 150-220°C, and the geothermal recovery efficiency varies in the range of 86 to 88 percent. A relative low basic solution concentration and a high working fluid concentration is helpful to improve the system efficiency under the satisfied separation condition. The minor variation of the system efficiency with variation of circulating ratio indicates that the vary of circulating ratio due to the environmental elements will not cause greet effect on system performance.

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Performance Analysis Hot Dry Rock Geothermal Resource Power Generation System Based Kalina Cycle