A review of high temperature cooling systems in tropical buildings

• Studies on applications of high temperature cooling in the tropics were reviewed.
• High temperature cooling can cut the air supply fan energy use by half.
• A custom designed low lift chiller can further utilize the potential energy saving.
• A detailed design/operation strategy of coupled air-water systems is essential.
• Membrane based air to air heat exchanger showed promising results for this context.

High temperature cooling is gaining more attention in commercial buildings of the tropical climates where temperature and humidity is high all year round. In this air-water system, radiant-convective cooling is provided into conditioned space through using higher chilled water temperature compared to conventional all air system. Radiant cooling panel, radiant slab cooling, passive/active chilled beams are the main design strategies for implementing this concept into buildings. This paper reviewed and summarized the recent published papers on applications of high temperature cooling systems in tropical buildings. The reported outcomes and conclusions from these studies were extracted and discussed to get a better understanding on overall performance of the systems which are designed based on this concept. The potential energy saving of this strategy was estimated to be in the range of 6–41% depending on design strategies and operational scenarios of system. Comfortable and healthy indoor environment is achievable for this design when a parallel air system satisfies latent load and ventilation requirement of space. Low air movement was the only reported comfort concern for this design since locally acclimatized occupants in the tropics prefer higher air movement compared to dry and temperate climates. Regarding the parallel air system strategy, DOAS with ceiling supply-ceiling exhaust is suggested to be the best choice to be coupled with high temperature cooling system. In addition, incorporation of energy recovery systems like membrane based air to air heat exchanger into DOAS can improve the overall efficiency of this design.