Thermodynamic modelling and analysis of low temperature Kalina cycle system for geothermal sources of India

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The India is having good potential for geothermal energy and is yet to be explored. The non-isothermal boiling nature of ammonia-water mixture paved the way for the development of Kalina cycle systems. In this work the low temperature Kalina cycle system is investigated with the aim of generating electric power from the geothermal resource at Indian climatic conditions. The study of the process is done using computer software to obtain the data of energy and exergy efficiency that could be generated form the geothermal heat source. Parametric analysis is conducted to examine the effects of some key thermodynamic parameters on the system performance. One of these parameters, ammonia concentration at turbine inlet, appears to have an optimum value with respect to the maximum cycle efficiency and net power output at the given operating conditions. Results indicate that a maximum cycle efficiency of 11.75 % can be achieved with 0.95 and 0.70 ammonia concentration at the turbine inlet and separator inlet respectively, operating at 418 K source temperature under Indian climatic conditions. The corresponding specific power and exergy efficiency are found to be 80.5 kW and 39.77 % respectively. Under same operating conditions, the maximum net power output of 82.24 kW can be achieved at 0.92 ammonia concentration at the turbine inlet. The present analysis gives lot of insight to understand the design parameters to utilize geothermal energy.