Feasibility of realizing daytime solar heating and radiative cooling simultaneously with a novel structure

Hu, Mingke; Zhao, Bin; Suhendri; Cao, Jingyu; Wang, Qiliang; Riffat, Saffa; Su, Yuehong; Pei, Gang

Abstract

Recent breakthroughs in preparing near-perfect emitters have made it possible to realize daytime radiative cooling under intensive solar radiation. However, a typical radiative cooler cannot deliver heat and may even cause an undesired cooling effect on cold days. Instead of rejecting the solar radiation back to the sky, this work proposes a new concept of capturing this “free” renewable energy while dumping waste heat through radiative cooling. The new structure features an upper solar-transparent radiative emitter and a lower solar absorber. Simulation results suggest that, to realize daytime solar heating and radiative cooling simultaneously, the emitter solar-absorptivity should be extremely low, and the absorbed solar heat should be instantly and effectively taken away by thermal carriers. With an ambient temperature of 25°C and a maximum solar irradiance of 1000 W/m2, the emitter can always reach a sub-ambient temperature if the absorber temperature is lower than 33.9°C in the non-vacuum case, and can exceed 70°C if the air cavity between the emitter and absorber is vacuumized. A performance simulation in three consecutive days in Shanghai reveals that the emitter can realize daytime radiative cooling with a temperature reduction of over 9.3°C from the ambient temperature around noon.

Citation

Hu, M., Zhao, B., Suhendri, Cao, J., Wang, Q., Riffat, S., Su, Y., & Pei, G. (2021). Feasibility of realizing daytime solar heating and radiative cooling simultaneously with a novel structure. Sustainable Cities and Society, 74, Article 103224. https://doi.org/10.1016/j.scs.2021.103224

• Journal Article Type: Article
• Acceptance Date: Jul 30, 2021
• Online Publication Date: Aug 3, 2021
• Publication Date: 2021-11
• Deposit Date: Aug 9, 2021
• Publicly Available Date: Aug 4, 2022
• Journal: Sustainable Cities and Society
• Print ISSN: 2210-6707
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 74
• Article Number: 103224
• DOI: https://doi.org/10.1016/j.scs.2021.103224
• Keywords: Transportation; Renewable Energy, Sustainability and the Environment; Civil and Structural Engineering; Geography, Planning and Development
• Public URL: https://nottingham-repository.worktribe.com/output/6009890
• Publisher URL: https://www.sciencedirect.com/science/article/abs/pii/S2210670721005023?via%3Dihub