A detailed investigation on thermal performance and energy savings of cool roof systems for composite climates of India

ABSTRACT

The rising worldwide temperatures leading to a spike in air conditioning to ensure thermal comfort in buildings is the root cause of the increase in energy demand in India's building sector. The roof of a building significantly adds to the heat gained on the top floor, accounting for 50–60% of the total heat gain. One sustainable way to reduce this heat gain is via cool roofing technology. Through examination and dynamic simulations with the Energy-Plus-based Design Builder software tool, this study explores different cool roof solutions. An experimental setup of a Reinforced Cement Concrete (RCC) roof with cement plaster, solar reflective paint, solar reflective tiles, and earthen pots have been created on the institute campus. Recordings were taken during the peak summer days and peak winter days, alongside simulations carried out to determine various factors such as Albedo, Surface Temperatures, Air Temperatures, Diurnal Heat Ingress, and the Building's Thermal Energy Consumption. The experiments have demonstrated that cool roof layers can considerably improve interior thermal comfort by minimizing heat transfer, which maintains a constant temperature over the bottom surface of the roof. By reducing heat gain by 33–71%, they can save energy by 21-26% compared to traditional RCC roof slab.

KEYWORDS:

• Cool roof
• heat gain
• thermal performance
• surface temperature
• energy consumption

Acknowledgement

The author is grateful to the Director, CSIR-CBRI, Roorkee for permitting the publication of this work. The author also thanks CSIR, New Delhi, and the Government of India for their financial support.

Credit

Kishor Kulkarni: Funding acquisition, Project administration, Conceptualization, Methodology, Application of statistical techniques, Creation of models, Reproducibility of results/experiments, writing review & editing, Garima Singh: Reproducibility of results/experiments, writing review & editing, statistical analysis and Renu Premi: Creation of models, Reproducibility of results, writing review.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Central Building Research Institute Roorkee: [grant no MLP082002].