Development of a night-time radiative sky cooling production & storage system: A proposal for a robust sizing and potential estimation methodology

• Published in: Applied thermal engineering Vol. 211; p. 118378
• Main Authors: Aketouane, Zakaria, Bruneau, Denis, Sempey, Alain, Bouzouidja, Ryad, Lagiere, Philippe, Raji, Saed, Roger, Pierre
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 05.07.2022; Elsevier BV; Elsevier
• Subjects: Air temperature; Ambient temperature; Cooling; Cooling systems; Courtyards; Design method; Effective sky temperature; Energy balance; Energy storage; Engineering Sciences; Extreme climate conditions; Flow velocity; Hydraulics; Mechanics; Prototypes; Radiative sky cooling; Sizing; Storage temperature; Temperature; Thermal modeling; Water circulation; Water pipelines; Water storage; Energy balance; Radiative sky cooling; Design method; Effective sky temperature; Model; Thermal modeling; Extreme climate conditions
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2022.118378

•A modeling framework has been proposed for assessing radiative sky cooling systems.•Four performance indicators are defined to design the radiative sky cooling system.•Estimation of energy consumption correlates well with metered data.•Improved design is of crucial importance to guarantee good performance. This paper proposes a sizing method to guide the design of water-circulating radiative sky cooling systems and water-based energy storage solutions. Following this method, the choice of operational flow rate in the radiative sky cooling (RSC) panels and the water storage is based on four indicators: sub-ambient temperature, cooling power density, minimum storage temperature and useful energy stored. The method is applied to the BaityKool Solar Decathlon Middle East (SDME) prototype in order to design a water-radiative sky cooling system with storage in the climatic conditions of Dubai. We developed passive strategies for the BaityKool prototype, including a multi-functional innovative exterior wall and a semi-indoor courtyard space, combined with active solutions (in particular a hydraulic radiative sky cooling system). The experimental campaign conducted on the RSC system over three successive nights in November (ambient air temperature between 22.7 and 31.4 °C) indicates an average cooling power of 30–45 W m−2 for a maximum sub-ambient temperature drop of 2.8 °C, and shows that great attention to the water pipes and storage insulation can lead to an increase in the thermal performance of radiative sky cooling systems.