Beschreibung
Introduction The depletion of fossil fuels is a well-known problem (Shafiee and Topal, 2009) and the concluding increase in energy cost (Nel and Cooper, 2009) leads to a trend to a more rational use of resources. Furthermore, the limited fossil fuel reserves urge the need to identify regenerative energy sources as a replacement. Here, this thesis is going to focus on systems used for the exploitation of heat sources. Renewable heat sources are mainly used in two fashions: the direct use of heat and the conversion of heat to power. Direct use of renewable sources for heating is possible for many heat sources and allows for recovery of heat on high as well as low temperature levels. Most common is the direct use of geothermal heat. The highest share of geothermal heat directly used is heat pump systems (71 % of the installed capacities worldwide) as reviewed by Lund et al. (2011). The same authors identify bathing and swimming applications (13 %) and space heating (11 %) as major applications. However, the direct use of heat is only possible, if the heat source and the consumer are close to each other. Furthermore, the focus on heating limits the plant operation mainly to cold days. For this reason, the limited consumption.
