Conference Year

2012

Keywords

heat pump, solar thermal collector, annual storage, heating system

Abstract

Aim of this paper is a theoretical and experimental investigation of a domestic heating system with heat pump using solar thermal collectors as the only heat source. In the system described, the heat pump uses an ice-water tank as annual storage system taking advantage of the phase change at 0°C. Energy is supplied to the storage system using low temperature solar thermal collectors. Low temperatures inside the solar collector lead to an increased annual yield. The thermal collectors can also be used to directly heat domestic hot water or to supply heat to the buildings heating system. Benefit of this system should be a significantly increased performance compared to a standard air to water heat pump while at the same time reducing its noise level. Additionally no drilling for geothermal probes is needed and no permission to use ground water is required. A theoretical model was built for this system and successfully validated using the field measurements. The field unit still had to fight several problems (evaporator too small, problems with control system) which lead to a very low overall seasonal efficiency of 1.43. But the measurement results could still be used to validate the heat pump and building model. Starting from the lessons learnt in the field, the system was dimensioned correctly and simulated accordingly. The seasonal efficiency achieved in the simulation increased to 2.4 which is comparable to air source heat pumps. It is expected that further modifications of the system could result in seasonal performance factors of 3.0-4.0. While this would be a fairly good performance and the noise pollution of the heat pump would be lower compared to air source heat pumps, the investment costs needed would grow considerably.

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