Modelling and Control of Reflected Heat from Light Shelves in Tropical Climates

Abstract

While light shelves enhance daylight inside buildings in tropical climates, there is a concern that the heat reflected from them will increase the cooling load inside a building. In this study, experiments are conducted under controlled conditions to understand the heat transmission characteristics of light shelves. The total heat reflected by a prototype of a light shelf is compared to the case of a similar setup with a no light shelf. Different materials were tested to evaluate the heat and light transmission. A mirror glass light shelf gave the highest illuminance, whereas an aluminium light shelf transmitted maximum heat. To explain the experimental results, a simulation model was created using the heat balance equation for the light shelf. The Mean square error between the simulation and experimental data is computed to predict the heat transmitted by the light shelf. The simulation model could reasonably replicate the trends obtained in the experimental data. The simulation model helps in controlling the heat transferred by light shelves in tropical climates.