An Experimental Investigation of Latent Thermal Storage for Radiant Cooling in Tropical Office Buildings

Latent thermal storage (LTS) is a promising technology for managing the electrical demand of building air conditioning systems. It works by shifting the system cooling load from on-peak to off-peak periods, which can significantly reduce electricity costs. From decarbonization perspective, LTS can also shift air-conditioning power demand to times when renewable energy is abundant, thereby encouraging renewable energy use and decarbonizing building cooling. This paper presents an experimental investigation into the application of LTS for radiant cooling in tropical office buildings. A specialized LTS test setup was built to provide high-temperature cooling water (above 16°C) to a radiant cooling system for air-conditioning in an outdoor chamber. The LTS system utilized a fatty acid phase change material (PCM) with a freezing point of 9.5°C, ensuring compatibility with standard water chillers. The experimental results show that by charging the cooling energy during the off-peak period (from 10:00 PM to 9:00 AM), the LTS system could satisfy the radiant cooling load for approximately 3 hours during on-peak operation. The potential for peak-load shifting was evaluated under two distinct two-hour scenarios. These findings are significant, offering valuable insights into how LTS can be used as a partial load shifting application for demand-response programs in building air-conditioning.