An innovative PCM system for thermal comfort improvement and energy demand reduction in building under different climate conditions

In recent years, applying phase change materials (PCMs) has attracted growing attention due to its potential to energy conservation with thermal comfort in the buildings. The proper use of PCM in a building can reduce the energy demand considerably, keeping the indoor temperature within the comfort range. One of the major issues associated with the use of PCM is the dependency of its performance on the climate conditions, such as the ambient temperature in which it is used. This study introduces an innovative double layer PCM system aim to improve thermal comfort conditions and minimize energy demand. In the scope of PCM performance improvement under different climates during hot and cold months, a constructive solution is the incorporation of two PCM types with different properties, such as melting temperature and enthalpy in room envelopes. The behavior of such a system under five different climatic regions with emphasis on dry and semi-arid climates as dominant climates of Iran was numerically investigated. The study of this new system is conducted by a room with one exterior and some interior boundary conditions in hot and cold months. In this work, The Fanger comfort model has been used for a comprehensive evaluation of new system's impact on thermal comfort conditions. The results showed that the double layer PCM system improves percentage of time in which the indoor thermal comfort conditions are met from 73% to 93% in dry climate, and from 63% to 75% in semi-arid climate in winter. Furthermore, the heating energy consumption is reduced by 17.5% in dry climate, and by 10.4% in semi-arid climate in the country of Iran.