20 September 2011

USING DEEP GEOTHERMAL ENERGY FOR HIGHER EFFICIENCY AND LOWER COSTS IN LARGE HEAT PUMPS


Today, it is mostly groups of conventional geothermal earthprobes that are used for supplying buildings that have a heating requirement of more than 100 kW. Drilling is
typically carried out to a depth of 100 to 200 metres. As more output is required, the number of earthprobes is increased, and this gives rise to the following problems: the space
requirement increases due to the minimum distance that has to be maintained between earthprobes, and the costs for connecting the earthprobes to the heat pump are also higher. In addition, a longer installation time is required. The aim of the project is to define the best drilling methods for geothermal earthprobes at
depths of between 300 and 800 metres, and to compare them with existing technologies. Obtaining heat from these depths means that fewer drillings are required, and the efficiency
of the overall system can thus be increased (source temperature above 20° C, no need for an antifreeze agent). Drilling to these depths increases the potential for utilising geothermal energy for the production of room heating, and the principle of “one building, one borehole” reduces the negative impacts on the environment from the use of geothermal energy.