Research Article

Thermal performance analysis of near infra-red reflection and green roof cooling techniques on buildings made of mild steel

¹ Department of Mechanical Engineering in Sustainable Energy; Pan African University Institute of Basic Sciences Technology and Innovation, Kenya
² Department of Mechanical Engineering, Jomo Kenyatta University of Agriculture and Technology, Kenya
³ Department of Agricultural and Biosystem, Jomo Kenyatta University of Agriculture and Technology, Kenya

^* e-mail: nkulemdlal@gmail.com

Received: 8 February 2023
Received in final form: 19 May 2023
Accepted: 12 July 2023

Abstract

This paper investigates the thermal performance of green roofs, cool roofs, and their combined effects in tropical climates. Although each technology has been studied independently for its potential to reduce cooling energy consumption in buildings, their combined effects have not been thoroughly examined in tropical climates. The study employed experimental and numerical methods, demonstrating that combining green and cool roofs can lead to even greater cooling energy savings. The research involved fabricating four identical cubicles made of mild steel sheets and placing them in an open space for testing under two operational conditions: closed window and open window/door. The combined green and cool roof technology achieved a temperature difference reduction of 4.14 °C compared to the original roof under the closed window and door state, with green and cool roofs achieving 0.72 °C and 0.79 °C, respectively. Combining green and cool roofs led to even more significant cooling energy savings, with 53.57 kWh energy savings compared to 20.1 kWh and 3.68 kWh for combined, green, and cool cubicles, respectively. The study found that combining green and cool roofs led to even more significant cooling energy savings, with 53.57 kWh energy savings compared to 20.1 kWh and 3.68 kWh for combined, green, and cool cubicles, respectively. The research suggests that combining these technologies can lead to greater cooling energy savings and highlights the potential benefits of green and cool roofs for tropical climates.