This is a paper presented by a group of German researchers during EUROSUN 2008 International Congress on Heating, Cooling and Buildings held in Lisbon, Portugal. Addressing the use of heat pump systems with boreholes together with solar thermal collectors, their project - âUnglazed Solar Collectors in Heat Pump Systems: System Concept and Dimensioningâ â is linked with Task 44 of the International Energy Agencyâs Solar Heating and Cooling Programme.
The two systems are measured and simulated in a TRNSYS modeling programme on a testing site in Germany. Validated data from these simulations show the interdependency of collector area, borehole length and heat pump system performance, as well as the significant influence that climate conditions (summer vs. winter) have on these systems. The choice of collector area and borehole length is crucial since it is reflected in both energy savings and investment costs.
Last but not least, the solar collector minimizes the risk which may be caused by unforeseen high heat extraction or a lower ground heat conductance.
Author: E. Bertram, J. Glembin, J. Scheuren, G. Rockendorf, G. Zienterra
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