Use of Low Enthalpy Geothermal Energy for Residential Heating

Abstract

Almost all the geothermal plants in France are associated with a heating network serving residential units and associated urban facilities. It is estimated that approximately 200,000 housing equivalents are at present connected to urban heating networks based on geothermal energy More than 80% of these are within the Paris region where a perfect set of conditions exists between an easily mobilized resource and a concentration of habitations of apartment dwellings. Two scenarios are met with; either a heating network already existed before the introduction of the geothermal heating, or a completely new heating network had to be constructed to exploit the available geothermal energy In the first case it was necessary to make the existing network compatible with the constraints imposed by the temperature level of the geothermal supply. In the second case it was necessary to design a routing that best optimized the geothermal energy under acceptable economic conditions. A number of the principles developed to bring about this optimization are presented here.