Direct-expansion solar-assisted heat pump coupled with crystallisation-controlled supercooled PCM for shifting building electricity demand

Kutlu, Cagri; Zhang, Yanan; Lyu, Qinghua; Su, Yuehong; Riffat, Saffa

Abstract

This paper proposes a novel approach for improving the performance of a direct-expansion solar-assisted heat pump (DX-SAHP) system by integrating a crystallisation controllable phase change material (PCM) and building energy demand shifting strategy. The proposed system aims to reduce buildings' energy consumption while utilizing solar energy efficiently. Sodium acetate trihydrate (SAT) as the crystallisation controllable supercooled PCM has a promising feature of releasing the stored latent heat when it is externally triggered, allowing the user to control the stored heat whenever needed. In the study, the PCM can store the thermal energy generated by the DX-SAHP during peak solar hours in an efficient way. This stored energy can be released when solar energy is unavailable, but the heating is requested. This approach not only reduces the load on the heat pump system but also makes efficient use of the stored thermal energy by crystallisation controllable PCM. A detailed controlling methodology of the system is given, and heating output is controlled considering the level of solar irradiance. The proposed system was modelled and simulated using MATLAB, and the results show that the integration of crystallisation controllable PCM and building demand shifting strategy can significantly reduce the energy consumption of the buildings. On the low solar radiation day, the COP improvement compared to the air source heat pump system was found 9.4%, this improvement value can reach 77% on high solar radiation days. The system can also effectively utilize solar energy and reduce the overall carbon footprint of buildings.

• Journal Article Type: Article
• Acceptance Date: Oct 17, 2023
• Online Publication Date: Oct 20, 2023
• Publication Date: Dec 15, 2023
• Deposit Date: Nov 21, 2023
• Publicly Available Date: Nov 22, 2023
• Journal: Energy and Buildings
• Electronic ISSN: 1872-6178
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 301
• Article Number: 113660
• DOI: https://doi.org/10.1016/j.enbuild.2023.113660
• Keywords: Electrical and Electronic Engineering, Mechanical Engineering, Building and Construction, Civil and Structural Engineering
• Public URL: https://nottingham-repository.worktribe.com/output/27582808
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0378778823008903?via%3Dihub
• Additional Information: This article is maintained by: Elsevier; Article Title: Direct-expansion solar-assisted heat pump coupled with crystallisation-controlled supercooled PCM for shifting building electricity demand; Journal Title: Energy and Buildings; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.enbuild.2023.113660; Content Type: article; Copyright: © 2023 The Author(s). Published by Elsevier B.V.