Simulation study on a Domestic Solar/Heat Pump Heating System Incorporating Latent and Stratified Thermal Storage

Abstract

Both solar and heat pump heating systems are innovative technologies for sustaining ecological heat generation. They are gaining more and more importance due to the accelerating pace of climate change and the rising cost of limited fossil resources. Against this background, a heating system combining solar thermal collectors, heat pump, stratified thermal storage, and water/ice latent heat storage has been investigated. The major advantages of the proposed solar/heat pump heating system are considered to be its flexible application (suitable for new and existing buildings because of acceptable space demand), as well as the improvement of solar fraction (extended solar collector utilization time, enhanced collector efficiency), i.e., the reduction of electric energy demand for the heat pump by management of the source and sink temperatures. In order to investigate and optimize the heating system, a dynamic system simulation model was developed. On this basis, a fundamental control strategy was derived for the overall co-ordination of the heating system with particular regard to the performance of the two storage tanks. In a simulation study, a fundamental investigation of the heating system configuration was carried out and an optimization was derived for the system control, as well as the selection of components and their dimensioning. The influence of different parameters on the system performance was identified, where the collector area and the latent heat storage volume were found to be the predominant parameters for system dimensioning. For a modern one-family house of 120 m2 living area with a specific annual heat demand of 60 kWh/(m2 a) for both heating and domestic hot water, a solar collector area of 30 m2, and a latent heat store volume of 12.5 m3 are proposed for the location of Wuerzburg (Germany). In this configuration, the heating system reaches a seasonal performance factor of 4.6, meaning that 78% of the building’s and users’ heat demand are delivered by solar energy. The results show that the solar/heat pump heating system can give an acceptable performance using up-to-date components in a state-of-the-art building.

A polyvalent heating system for a passive house based on renewable energy sources

“…Ряд работ [16][17][18][19][20] посвящен энергетическому и эксергетическому анализу применения теплонасосных технологий при теплообеспечении потребителей. Отмечено, что максимальная эффективность достигается при создании комбинированных систем теплоснабжения, которые включают в себя тепловой насос и солнечные коллекторы.…”

Modeling and optimization of a solar assisted heat pump using ice slurry as a latent storage material

“…Using an integrated ice storage/solar thermal system can also significantly improve collector performance (Trinkl et al, 2009). The efficiency of a solar collector is highly dependent on the inlet fluid temperature (Duffie and Beckman, 2006): Colder inlet fluid temperatures result in reduced thermal losses to the ambient and increased collector efficiencies.…”

“…As such, Trinkl et al (2009) used the temperature difference between the bottom of the warm water storage tank (T WWST ) and the ambient air (T amb ) to estimate potential solar collector efficiencies.…”

Modeling of an ice storage based on a de-icing concept for solar heating applications

“…The ice storage is used in this application as a heat source for the heat pump and it is loaded by the solar field, which can also be used as a direct heat source for the heat pump. Explanations of different solar-ice systems can be found elsewhere (Trinkl et al, 2009;Winteler et al, 2014;Carbonell et al, 2014a). A solar-ice system can be seen as an alternative to ground source heat pump systems when for example, regulations forbid to drill boreholes.…”

“…To the author's knowledge, all the other ice storage concepts used on the market or in demonstration phases for solar-ice applications use ice-on-coil where de-icing is not possible, see e.g. Trinkl et al (2009) andWinteler et al (2014).…”