DIRECT HEAT UTILIZATION OF GEOTHERMAL RESOURCES

Direct utilization of geothermal energy consists of various forms for heating and cooling instead of converting the energy for electric powe r generation. The major areas of direct utilization are (1) swimming, bathing and balneology, (2) space heating and cooling including distri ct heating, (3) agriculture applications, (4) aquaculture applications , (5) industrial processes, and (6) heat pumps. Major direct utilizati on projects exploiting geothermal energy exist in about 38 countries, and the estimated installed thermal power is almost 9,000 MWt utilizin g 37,000 kg/s of fluid. The world-wide thermal energy used is estimate d to be at least 108,100 TJ/yr (30,000 GWh/yr) - saving 3.65 million T OE/yr.. The majority of this energy use is for space heating (33%), an d swimming and bathing (19%). In the USA the installed thermal power i s 1874 MWt, and the annual energy use is 13,890 TJ (3,860 GWh). The ma jority of the use (59 %) is for heat pumps (both ground coupled and wa ter source), with space heating, bathing and swimming and fish and ani mal farming each supplying about 10%. Copyright (C) 1996 Published by Elsevier Science Ltd.