Exploring membrane-assisted radiant cooling for designing comfortable naturally ventilated spaces in the tropics

Abstract

This research proposes the use of membrane-assisted radiant panels to improve the thermal comfort of naturally ventilated spaces in hot and humid climates. These radiant panels are capable of conditioning naturally ventilated spaces, which is impractical with conventional mechanical cooling systems. For conventional systems, a permeable envelope will result in energy wastage from conditioned air escaping or condensation occurring on the radiant surfaces. In our system, there is no airconditioning and we avoid condensation by separating the radiant surfaces from humid air using a membrane transparent to thermal radiation. The membrane-assisted radiant panels are an unutilized technology for architects to design comfortable naturally ventilated spaces. We propose a cooling system based on the technology and discuss the architectural implications, particularly the permeability of the building envelope and requirements for mechanical spaces, of employing this system in a case study that is a naturally ventilated classroom. Our system is compared to conventional cooling systems. Although our system requires a ceiling space reconfiguration, it does not require duct works and envelope retrofits. The comparative case study shows a potential 52% reduction in cooling energy demand from initial estimation. Considering the trade-offs, our system can be a good alternative for retrofit projects.

Resolving Radiant: Combining Spatially Resolved Longwave and Shortwave Measurements to Improve the Understanding of Radiant Heat Flux Reflections and Heterogeneity

“…The general population largely associates heat with air temperatures, but in warm climates the majority of heat experienced by people in the urban environment is in the form of radiant heat transfer (Hoppe, 1992;Thorsson et al, 2007;Johansson et al, 2014;Middel et al, 2014;Lindberg et al, 2016). We have built human body heat models (Teitelbaum et al, 2020), and built experimental radiant pavilions (Chen et al, 2020;, which have both demonstrated how as air temperatures approach skin temperature the body's necessary metabolic heat rejection can become almost completely dependent on radiant heat heat transfer. We argue it is therefore critical to explore new ways to model and measure radiant heat transfer that include its complex geometric and spectral properties.…”