A Successful Example of a Retrofit to a Geothermal District Heating System

Abstract

In order to utilize low temperature geothermal, it is often necessary to retrofit district heating systems in China. A coal burning district heating system which is known to have a floor area of 120,000m2 has been successfully retrofitted to 74- 47C geothermal heating system. First, the peak heating load has to be analytically determined from previous boiler plant records of circulating flow rate and temperature. Then the heat output of the terminal equipment has to be analyzed and confirmed. The circulating water design temperature difference can be found as a changeable limit. Making use of this limit a suitable LMTD can be chosen for the titanium plate-type exchanger of the geothermal system for saving initial capital and raising the heat output of the geothermal well. The retrofitted geothermal district heating system was used 3 years. It has shown economic and environment benefits.