Using phase change material as an energy-efficient technique to reduce energy demand in air handling unit integrated with absorption chiller and recovery unit–Applicable for high solar-irradiance regions

Abstract

In the Saudi Arabia climate zone, the share of cooling in buildings sector energy usage is 66%. In this study, the main goal is to reduce energy usage in the cooling sector, which was investigated with the introduction of phase change material (PCM) and recovery unit (RU). By incorporation of the enthalpy-porosity technique into the energy equation, the thermal behavior of the PCM-based walls along with the ceiling was modeled transiently throughout the year. Taking into account high solar intensity in Saudi Arabia region, the sol-air temperature was defined to consider the effects of solar irradiance on the building envelopes. To meet the cooling requirements in the building, an air handling unit (AHU) combined with an absorption chiller was used. The annual calculations affirmed that by adding PureTemp (melting temperature of 22-24°C) the heat gain decreased by 7.13% which in turn led to an energy-saving by 47.3kWhm2. Moreover, due to the incorporation of a RU into AHU, the energy demand in AHU was lowered by 63.8kWhm2 (equivalent to an 8.38% reduction). Finally, by using the energy-efficient techniques of adding PCM and installing RU, the AHU energy usage was decreased by 14.6% which was equivalent to a 111.1kWhm2.year energy-saving