| Abstract |
Geothermal energy was used by early man primarily for direct heat such as cooking, and balneology. Today it is used for space conditioning, industrial processing and agribusiness applications. District heat has received recent interest especially in the US. At present, over 2,000 are utilized in the world for direct use applications. Generally, conventional equipment is used to extract the heat from geothermal fluids, with materi selection n g dictated by the water and gas chemistry. Heat exchangers and piping have been adapted to geothermal use, along with water-to-water heat pumps. Cascading of the water can increase the utilization efficiency as illustrated in Japan and the USSR. |