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Efficiency of Combined Solar Thermal Heat Pump Systems



Author(s)

Werner Lerch, Andreas Heinz, Richard Heimrath and Christoph Hochenauer

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DOI:10.17265/1934-7359/2015.06.011

Institute of Thermal Engineering, Graz University of Technology, Graz 8010, Austria

In this project, different combinations of solar energy and heat pump systems for preparation of DHW (domestic hot water) and space heating of buildings are analyzed through dynamic system simulations in TRNSYS (Transient System Simulation Program). In such systems, solar thermal energy can be used, on one hand, directly to charge the buffer storage and, on the other hand, as heat source for the evaporator of the HP (heat pump). In this work systems, in which solar heat is only used directly (parallel operation of solar and HP), systems using the collectors also as a heat source for the HP are analyzed and compared to conventional air HP systems. With a combined parallel solar thermal HP system, the system performance compared to a conventional HP system can be significantly increased. Unglazed selectively coated collectors as source for the HP have the advantage that the collector can be used as an air heat exchanger. If solar radiation is available and the collector is used as source for the HP, higher temperatures at the evaporator of the HP can be achieved than with a conventional air HP system.

Solar heat pump, solar system, heat pump, low energy buildings.