A Low Temperature Geothermal Space Heating Demonstration Project

Abstract

A demonstration project for the State of Idaho utilizes 170°F geothermal water from well sources established in 1892. The project is a retrofitted gas fired system serving three buildings. Two separate water loops are interacted through a primary heat exchanger. The geothermal loop is capable of delivering up to 400 gpm at 166°F to the exchanger which transfers about eight million Btuh to the space heating loop. The spent geothermal water is cooled and aerated, then discharges to the Boise River. The second loop is a closed system including the existing boiler, pumps, and piping retrofitted to the new heat exchanger. In addition to demonstrating the technology to utilize low temperature sources of space heating, the project examines economic feasibility, environmental impacts and materials effect.