A simulation study on performance improvement of solar assisted heat pump hot water system by novel controllable crystallization of supercooled PCMs

Kutlu, Cagri; Zhang, Yanan; Elmer, Theo; Su, Yuehong; Riffat, Saffa

Abstract

Domestic hot water (DHW) has a significant share in building’s energy consumption. In order to reduce this consumption, various solutions have been proposed such as controlling the system in an efficient way, using renewable sources and using phase change materials (PCM) in the system to increase heat capacity. However, this study is not only offering heat capacity improvement of the DHW storage unit but also proposing that energy efficiency can be improved by controlling the heat releasing time of the PCM. In this study, supercooled PCM tubes are placed in a water tank and charged with a solar assisted heat pump unit, these supercooled PCM tubes can then be discharged anytime when the hot water is required. In this paper, a transient thermodynamic model is built for the whole system including solar collector, heat pump, water tank with PCM and DHW demand profile. System components are modelled and a 24 h of demand profile is used in simulation for a UK home for summer and spring weather conditions. The results show that the PCM tubes effectively compensate the morning peak hot water demand and reduce daily energy consumption around 12.1% and 13.5% by shifting heating provision from immersion heater to solar heat pump.

Citation

Kutlu, C., Zhang, Y., Elmer, T., Su, Y., & Riffat, S. (2020). A simulation study on performance improvement of solar assisted heat pump hot water system by novel controllable crystallization of supercooled PCMs. Renewable Energy, 152, 601-612. https://doi.org/10.1016/j.renene.2020.01.090

• Journal Article Type: Article
• Acceptance Date: Jan 20, 2020
• Online Publication Date: Jan 21, 2020
• Publication Date: Jun 1, 2020
• Deposit Date: Apr 6, 2020
• Publicly Available Date: Jan 22, 2021
• Journal: Renewable Energy
• Print ISSN: 0960-1481
• Electronic ISSN: 1879-0682
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 152
• Pages: 601-612
• DOI: https://doi.org/10.1016/j.renene.2020.01.090
• Keywords: Supercooled PCM; Solar assisted heat pump; DHW; Transient thermodynamic simulation
• Public URL: https://nottingham-repository.worktribe.com/output/3905405
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0960148120301099
• Additional Information: This article is maintained by: Elsevier; Article Title: A simulation study on performance improvement of solar assisted heat pump hot water system by novel controllable crystallization of supercooled PCMs; Journal Title: Renewable Energy; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.renene.2020.01.090; Content Type: article; Copyright: © 2020 Elsevier Ltd. All rights reserved.