State of the art of the technology of high temperature heat pumps for geothermal district heating applications

Abstract

It is well known that energy can be exploited from renewable low temperature heat sources like waste water, sea- or ground water with large centrifugal industrial type heat pumps. Centrifugal heat pump technology is approved and very reliable. Already since more than three decades centrifugal heat pumps are reducing CO2 emissions and are supplying hot water up to 90°C to district heating systems. In most cases the heat is recovered from low temperature heat sources. However, it is quite new to the public that with heat pump technology energy can also be exploited from high temperature heat sources like geothermal water. With an intelligent heat pump system the district heating return temperature can be boosted and at the same time the exploitation of the geothermal well can be increased. In this paper three examples of large centrifugal heat pumps in district heating applications using ground, Neocomien and Dogger water will be presented.