Working fluids and systems for recovering geothermal or waste heat

Abstract

Energy is efficiently extracted from geothermal wells by flashing a portion of the hot fluid from the well into steam and using the steam and the hot fluid to heat an operating fluid in a closed system wherein the temperature and pressure are such that the operating fluid vaporizes and the fluid has sufficient superheat to avoid condensation when expanded in a prime mover such as a gas expansion gas turbine that has at least 75% conversion efficiency. Additionally, the operating fluid as a vapor has a specific heat that is at least 50% of the specific heat of the operating fluid as a liquid over the temperature range of 100.degree. F. to 250.degree. F. under the operating pressures of the process. Instead of using the steam to heat an operating fluid, it may be applied directly to a steam turbine. Additionally the steam may be washed before application to the turbine.

Dependencies are inferred from the claim text.