Investigation of an integrated system combining an Organic Rankine Cycle and absorption chiller driven by geothermal energy: Energy, exergy, and economic analyses and optimization

Abstract

This study aims to investigate a novel hybrid system for combined cooling and power (CCP) driven by geothermal energy. This study is performed using energy, exergy, and economic analyses. The results of this study show that application of LiBr absorption chiller downstream of the Organic Rankine Cycle (ORC) cycle increases the energy efficiency of the system from 9.3% to 47.3%. But it decreases the exergy efficiency from 15.6% to 4.6%, mainly due to the increase in the exergy destruction of the system. By definition of a new parameter called the electricity and cooling cost for this hybrid system, the results show this parameter decreases from 0.0552 to 0.0028 $/kWh when the LiBr absorption chiller cycle is added. Moreover, a multi-objective optimization of this hybrid system is carried out by the MOPSO algorithm for two objective functions including cost of electricity and cooling (CEC), and exergy efficiency (ηex). The results show that the optimum electricity and cooling cost and exergy efficiency are 0.0033 $/kWh, and 6.8%, respectively.