Energy-efficient mitigation measures for improving indoor thermal comfort during heat waves. (15th November 2020)

• Record Type: Journal Article
• Authors: Zhou, Xiaohai; Carmeliet, Jan; Sulzer, Matthias; Derome, Dominique
• Is Part Of: Applied energy. Volume 278(2020)
• Publication Date: 2020-11-15
• Subjects: Urban heat island effect -- Whole building heat and moisture model -- Hygroscopic material -- Moisture desorption -- Latent heat -- Energy efficiency -- Cooling; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2020.115620
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: A numerical model is developed to study indoor thermal conditions during heat waves. Moisture buffering can have an important influence on the indoor thermal conditions. Pre-cooling before the start of a heat wave can lower indoor temperature moderately. Moisture-desorption cooling has a large potential in reducing indoor heat stress. Abstract: Urban areas are increasingly impacted by the urban heat island effect, especially during heat waves. In the context of improving energy efficiency in buildings, passive and energy-efficient cooling methods are needed for reducing indoor heat stress and lowering building energy consumption during heat waves. In this study, a whole building simulation model that includes both moisture and heat transport in wall envelopes and indoor environment is developed. An analytical solution and two test cases are used to validate the developed model. The developed model is applied to study indoor thermal conditions in urban areas in Zurich, Switzerland in a hot summer. The results show that indoor temperature could not be accurately simulated when moisture transport in the wall envelopes is neglected. Due to the urban heat island effect, night ventilation is not sufficient to cool down the indoor environment during the heat wave in the urban area. The potential of precooling before the heat wave and moisture-desorption cooling from hygroscopic materials have been studied to reduce indoor heat stress in the urban area. The average operative temperature during the heat wave can be reduced by 0.43 °C by precooling before the start of the heat wave, whereas desorption cooling from hygroscopic materials could reduce the average operative temperature during heat waves by 1.31 °C. A combination of these two mitigation measures could lead to enhanced passive cooling effect. There is a large potential of using desorption of hygroscopic material to reduce heat stress during heatwaves, while minimizing energy consumption of buildings.