Small-Scale Organic Rankine Cycle for Geothermal Applications

Abstract

In waste heat power generation, heat energy can be recovered using a binary cycle system such as an Organic Rankine Cycle plant. The working fluid will likely be a commercial refrigerant. The turbine generator has a significant bearing on the technical performance and financial viability of the overall system. Turbine generators in commercial power generation use in NZ are sourced from overseas and are of high power ratings, upwards of tens of megawatts. This hinders the utilization of many sources of waste heat such as the waste heat of a geothermal plant as these call for several units in the kilowatt range. We are developing a 50 kilowatt electrical power turbine generator prototype to fill this niche. Our plan is to develop a modular turbine generator that meets the current and future market demand for waste heat power generation. The waste heat could come from sources such as the petrochemical industry, solar, geothermal, fossil fuel power generation and the waste industry. This is part of the Fitzroy R&D programme to build a modular Organic Rankine Cycle power generation system with a target power output of 50 kilowatts electrical power supported by Callaghan Institute. The unit generation price will be just slightly higher than large scale geothermal power generation in order to be commercially viable. In order to achieve this, the turbine generator will be designed for high volume manufacturability right from the start of R&D.