Passive cooling of buildings with phase change materials using fins to increase the effectiveness of thermal storage units

Abstract

Buildings consume substantial energy annually, primarily for lighting, cooling, and air conditioning. Alternative cooling technologies like free cooling are being explored in response to environmental concerns. This study investigates using phase change material (PCM) for passive cooling, reducing reliance on conventional air conditioning. PCM is charged at night using cooler ambient air and discharged to cool indoor spaces during the day. The PCM selected for this study, OM 21, has a phase change temperature of 21 °C and a latent heat of 180 kJ/kg, making it suitable for the temperature range between night- time ambient air (16-17 °C) and the desired room temperature (25 °C). Experimental setups included heat exchangers of 7-meter copper tubes surrounded by 0.5 mm thick aluminum fins. The setups tested various configurations of condenser blocks, including both series and parallel arrangements, to optimize thermal contact and heat transfer. Results indicated that series-connected condenser blocks provide more uniform charging and discharging, enhancing the system’s effectiveness. The study highlights the potential of PCM-based systems to offer a sustainable and scalable solution for building cooling. Future research will further optimize these systems, explore PCM variants, and utilize CFD modeling to improve design precision and system performance.