Experimental and Numerical Analysis on Effect of Passive Cooling Methods on an Indoor Thermal Environment Having Floor-Level Windows

Abstract

Natural ventilation is a common passive cooling method for improving air quality and thermal comfort; however, hot temperatures in summer and safety and privacy issues at night often result in its unideal performance. Therefore, we proposed the use of floor-level windows, mainly combined with microclimate improvement, to improve the indoor thermal environment by enhancing the cooling effect of natural ventilation during summer. Our study area was a house in Machida, Tokyo. We evaluated the effectiveness of our method in improving the indoor thermal environment in summer and performed a numerical simulation, while illustrating the detailed horizontal and vertical distribution of airflow in the house through the floor-level windows. The influence of different window types and opening angles of floor-level windows on ventilation and cooling was determined using the simulation. We found that: (a) natural ventilation-based passive cooling methods reduced semi-outdoor and indoor temperature and increased the humidity; (b) the airflow formed an indoor wind path; south-westerly inflow was from western floor-level windows and the skylight, and the outflow was from northern floor-level windows; and (c) the side hung windows (with an opening angle of 60°) were an ideal option to improve indoor airflow. However, there was no improvement in the passive cooling performance, due to the inflow of warmer outside air.

Optimization of Landscape Spatial Configuration and Form for Thermal Comfort: A Case Study of Urban Square, Shanghai

“…The sensible heat flux is related to the temperature difference and V a . The latent heat flux is related to the water vapor partial pressure difference and V a , which are modeled in this study as a function of the convective heat transfer coefficient, CHTC (W m −2 K −1 ) [66], and the evapotranspiration moisture flux rate, E (kg m −2 s −1 ) [67], respectively, with the mean values from the related studies [8,61,[68][69][70][71][72]. Surface temperatures were not measured by the equipment but by observing the near-surface air temperature as the initial surface temperature.…”

“…In this study, only a diurnal mean value could be taken based on related studies [93,94]. The study area subsurface was a totally hard material and did not address moisture and heat features of the lawn; the canopy 3D modeling used cylinders that could be modified for finer detail in association with LiDAR [62,69,95]. These will be further investigated in the future.…”

Influence of deflectors on indoor airflow velocity distribution under natural ventilation conditions

“…Buildings incorporating natural ventilation often exhibit energy costs that are 40% lower than those relying on air conditioning. In regions with comfortable outdoor climates, natural ventilation serves as a cost-free cooling resource (Ayata and Yıldız, 2006;Odi et al, 2022;Qin et al, 2022). Beyond delivering fresh air to interior spaces,…”