Impact of post-rainfall evaporation from porous roof tiles on building cooling load in subtropical China. (September 2018)

• Record Type: Journal Article
• Authors: Zhang, Lei; Zhang, Rongpeng; Hong, Tianzhen; Zhang, Yu; Meng, Qinglin
• Is Part Of: Applied thermal engineering. Volume 142(2018)
• Page Start: 391
• Page End: 400
• Publication Date: 2018-09
• Subjects: Rainfall event -- Evaporative cooling -- EnergyPlus -- Building energy simulation -- Cooling load -- Subtropical China; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2018.07.033
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: A novel simulation method for evaporation from porous roof tiles was proposed. EnergyPlus Runtime Language was used to develop an evaporative cooling module (ECM). The ECM was validated using experimental results reported in literature. Dynamic behaviors of heat and moisture transfer of porous roof tiles were simulated. Effects of evaporation from porous roof tiles on building cooling load were analyzed. Abstract: Rainfall occurs frequently in subtropical regions of China, with the subsequent water evaporation from building roofs impacting the thermal performance and the energy consumption of buildings. We proposed a novel simulation method using actual meteorological data to evaluate this impact. New features were developed in EnergyPlus to enable the simulation: (1) an evaporation latent heat flux source term was added to the heat balance equation of the external surface and (2) algorithms for the evaporative cooling module (ECM) were developed and implemented into EnergyPlus. The ECM experimental results showed good agreement with the simulated results. The ECM was used to assess the impact of evaporation from porous roof tiles on the cooling load of a one-floor building in subtropical China. The results show that the evaporation process decreased the maximal values of the external and internal roof surface temperatures by up to 6.4 °C and 3.2 °C, respectively, while the lower internal surface temperature decreased the room accumulated cooling load by up to 14.8% during the hot summer period. The enhanced EnergyPlus capability can be used to evaluate the evaporative cooling performance of roofs with water-storage mediums, as well as to quantify their impact on building cooling loads.