Review on phase change material based free cooling of buildings-The way toward sustainability

The present world energy scenario signifies the importance of renewable energy utilization and paves the pathway towards green and net zero energy building concepts for a sustainable future. In the recent years, substantial energy is spent in building space heating/cooling applications to meet the human comfort requirements. In order to reduce the unnecessary losses associated with the buildings, several advancements toward energy efficient concepts are also being proposed and implemented in many buildings. Free cooling is one such novel concept through which building cooling demands can be met without compromising the indoor air quality. Free cooling concept stores the abundant atmospheric night cool energy in phase change materials (PCM) and uses the stored energy during the day hours to achieve the desired room comfort conditions. This review article aims to update and consolidate the substantial work carried out in the recent years by various researchers on free cooling technology using PCMs in latent heat thermal energy storage (LHTES) systems. In addition, future potential of free cooling technologies, scope for further improvement, policies that needs be promoted by the government toward its sustainability to ensure market penetration of free cooling technologies are also discussed in detail.