Binary Generator Refrigerants -- Picking the Right Stuff

Abstract

Four commercially available refrigerants are analyzed as the working fluid in an organic Rankine cycle power generation system. The system included the geothermal production well, injection well, cooling tower, and usual binary equipment components. A computer program simultaneously calculated the net electrical power available for sales for each of the refrigerants. Key equipment duties were also calculated, as well as refrigerant properties, and system pressures and temperatures. This information is presented in a series of plots. Three example problems resulted in the selection of three different refrigerants based on system requirements and geothermal water quality. The minimum obtainable geothermal water effluent temperature varies considerably between refrigerants, and is a major consideration in refrigerant selection.