Long-Term Experience from a Heat Pump Plant in Lund, Sweden, Using a Low-Temperature Geothermal Aquifer

Abstract

All heat from the heat pumps is supplied to the district heating network for the town of Lund. The plant is operating at base load and covers almost 50% of the total heat demand, equal to 300 Experiences of the operation of the heat pump plant will be reported. Due to environmental reasons the cooling media of the two heat pumps will be changed from to in 1994 and 1995 respectively. The anticipated results of the conversion will also be presented in the paper. In late 1984 the first heat pump unit was connected to the geothermal wells and about one year later another heat pump unit was connected. In total 9 wells to about 700 meters of depth were drilled and completed as huge groundwater wells. Four wells are dedicated for production and the rest for injection. The water production capacity from the wells is 100 140 and the reservoir temperature was initially about 22 - 23?C. The total thermal output from the heat pump units is 47 (Bjelm et 1984). The reservoir rock belongs to Campanian of Cretaceous age and is a rather homogeneous calcareous sandstone. Thorough hydraulic, thermal and chemical investigations were carried out during a full scale study where well materials and final well construction was defined. The subsurface reservoir reactions have been monitored since start-up and some results are discussed in the article. Furthermore, certain well and filter behaviours and reservoir technological experiences are presented.