Energy efficiency and thermal comfort evaluation of rooms built using different insulating materials

Abstract

The aim of this study is to compare and evaluate the thermal performance of polyurethane foam insulation boards against other conventional roof insulation solutions. The site chosen for this study is located in New Delhi, India. Six typical office-sized rooms were constructed: four naturally ventilated and two equipped with air conditioning systems. Thermal comfort and energy efficiency of these rooms were assessed by an experimental study in accordance with ANSI/ASHRAE Standard 55-2017 and GRIHA standard. Room air temperature, humidity, wall and ceiling temperatures, air velocity, thermal flux, light intensity, and energy consumption of the air conditioning system was measured for an entire calendar year (February 2023 to January 2024). Using these measurements, thermal comfort and energy measurement indices, namely, the predicted mean vote and percentage of people dissatisfied and energy performance index were calculated. The performance of different insulation materials was compared and the foam insulation was found to be the most effective. It enhances thermal comfort by reducing peak temperatures; maintains stable indoor conditions and significantly reduce the energy consumption of to maintain thermal comfort. A 50 mm foam insulation in the roof achieves an average annual electrical energy savings of 63.6% as compared to the non-insulated room.