ABSTRACT
Faced with the problems of increasing energy scarcity and ongoing environmental deterioration, phase change materials (PCM) have attracted a lot of attention recently for improving building energy performance. Utilizing the PCMs in buildings is one of the efficient approaches to reduce the heat penetration into the buildings. In this work, the thermal performance of a building equipped with PCM roof is analyzed and compared with a plain roof building. The uniqueness of this study is to analyze the effect of PCM experimentally and numerically through parametric investigation with different PCMs (HS29 and OM29), encapsulation materials (aluminum and steel) and PCM thickness. The experimental analysis shows that the PCM incorporated roof decreased the inner room temperature of the building by 2°C vis-à-vis plain roof and hence helps reduce the cooling load and enables passive cooling of the building with energy savings. A numerical analysis was carried out using COMSOL and validated with maximum and average errors of 7.43% and 4.87% respectively. The parametric investigation from the validated model indicates that the PCM OM29 is effective compared to HS29 in terms of temperature reduction. The steel encapsulating panels are observed to be better than aluminum at the peak sunshine hours while the aluminum panel is effective for the other periods. It is observed that the increase in PCM thickness augments the reduction in heat transfer while the 6 cm PCM thickness showed a higher temperature reduction by 3.6°C vis-a-vis 2 cm PCM thickness.
Nomenclature
qin | = | Radiation flux W/m2 |
hout | = | Outside heat transfer coefficient W/m2 K |
Tatm | = | Atmosphere Temperature °C |
Tamb | = | Ambient temperature °C |
K2 | = | Thermal Conductivity of inner roof W/m K |
Hin | = | Inner heat transfer coefficient W/m2 K |
Troom | = | Room Temperature °C |
Ki | = | Thermal conductivity W/m K |
Cpliquid | = | Specific heat of liquid PCM, kJ/kg K |
Cp | = | Specific heat, kJ/kg K |
q | = | Heat flux, W/m2 |
Ti | = | Initial Temperature,°C |
Tf | = | Final Temperature,°C |
Tsur | = | Surface Temperature,°C |
Greek symbols | = | |
ρ | = | Density, kg/m3 |
ε | = | Emissivity co-efficient |
= | Heat flux | |
α | = | Absorption co-efficient |
t | = | Time in hours |
Disclosure statement
No potential conflict of interest was reported by the authors.
Additional information
Notes on contributors
Venkatesh G
Mr. Venketesh G is an Assistant Professor in the Jawahar Engineering College, Chennai, India with 12 years of teaching experience and currently perusing doctoral degree in Anna University. His research areas of interest include thermal storage, computational thermal analysis, and building thermal management applications.
Sundararajan Rajkumar
Dr. Sundararajan Rajkumar has 22 years of academic and research experience, as well as 7 years working experience in the industry. His areas of research include engine combustion and emission modelling, alternate fuels and thermal energy storage systems.
Geetha N.B.
Dr. Geetha N.B. has over twenty years of experience in teaching and research. Her research areas of interest include energy efficient buildings, heat transfer, heat exchanger, and computational fluid dynamics