Abstract:
Air Conditioning and Mechanical Ventilation (ACMV) Systems are often used to maintain the thermal
comfort and the indoor air quality in office buildings in tropical climates. These ACMVs usually account
for more than 50% of the total energy consumption of the buildings. Compared to other available
technologies, use of Phase Change Materials (PCMs) has been identified as an attractive innovative
technology to reduce the peak cooling load and also to shift the peak cooling load to after office-hours.
Temperature of building envelopes constructed using conventional materials such as bricks and concrete
tend to vary with the surrounding environmental conditions, as they only absorb or release the sensible
heat. On the contrary, PCMs can absorb or release much larger amount of thermal energy from/to the
surrounding as latent heat, while maintaining the building envelope temperature unaffected under varying
environmental conditions. Thus, conventional building envelopes accompanied with PCMs are able to
significantly reduce the external heat gains into the conditioned spaces of the buildings, resulting a
significant reduction in the peak cooling load. This study is mainly focused on exploring the applicability
of PCMs for hot and humid tropical climates. Numerical analysis supported and validated by an
experimental program and a case study revealed that by covering exterior of building envelop with 5 mm -
10 mm thick PCMs can reduce the building peak cooling load by 8% - 12%. Moreover, it was found that
the peak cooling load could be easily shifted to after office hours by increasing the PCM thickness.
Economic analysis showed that the PCMs with higher thermal cycles reduces the pay back periods up to 2
- 3 years and, further supported the use of low-temperature PCMs for building applications. Findings of
this study recommend to incorporate the PCMs on the building envelops of the sunlit walls to reduce the
peak cooling load of the building with the aim of reducing the energy consumption by the ACMV system.
Citation:
Wijewardane, M.A., Figurado, S.A., Kajaharan, M., Weerasinghe, N.D.A.M., & Ranasinghe, R.A.C.P. (2017). Applicability of phase change materials (PCMS) for peak load shifting of air conditioning and mechanical ventilation (ACMV) systems of office buildings in tropical climates. In Y.G. Sandanayake, T. Ramachandra & S. Gunatilake (Eds.), What’s new and what’s next in the built environment sustainability agenda? (pp. 33-39). Ceylon Institute of Builders. https://ciobwcs.com/downloads/WCS2017-Proceedings.pdf