The cascaded system of utilising low-temperature geothermal waters for heating and consumptive purposes

摘要

The following project will be completed in Slomniki, a town in southern Poland, approximately 30 km north of Krakow. A pilot installation of low-temperature thermal water recovery and distribution is expected to be made; the temperature of the water is about 20°C and is obtained from Cenomanian (≈200 m b.s.) and Dogger wells (≈640 m b.s.). With the aid of heat pumps brine water will be used for heating purposes, as well as for domestic purposes. The geothermal potential of water bearing horisons has been estimated on the basis of the results achieved from four wells; these have been accomplished in town and the surrounding area in the 1970s. A newly made well is very likely to make access to the bed of 50-100 m~3/h capacity. It is expected that in this way thermal power will be obtained at the level of 1-2 MW_t. Two sorts of consumers are taken into consideration: 1. housing estates with blocks of flats (the so-called concentrated system), with heating mains working in connection with gas boiler houses. The mains will work together with the heat pumps functioning on the basis of brine waters, 2. individual houses (the so-called scattered system) furnished with 18°C water supporting local heat pumps. The chief aim of the project is to lower the investment costs of building a geothermal heat generating plant, where the costs of wells reach as many as 50-60%. This may result in the rapid development of the utilisation of thermal energy in the local area.