A comparative review on the application of radiant low-temperature heating and high-temperature cooling for energy, thermal comfort, indoor air quality, design and control

Radiant low-temperature heating (LTH) and high-temperature cooling (HTC) has become popular due to their high energy efficiency, thermal comfort, and improving indoor air quality. This system has been investigated in many studies from theory to practical applications. In this review article, LTH/HTC systems based on their results on energy usage, thermal comfort, indoor air quality, design and control are analysed and discussed. Furthermore, the radiant system with all-air systems are compared and the application of a hybrid system in different climate conditions is also presented. The outcome of this study revealed that in many studies radiant LTH/HTC systems can save between 10 and 30% energy and provide better thermal comfort compared to the all-air system. Moreover, combining a radiant system with a small-sized air system has a positive impact on indoor air quality and thermal comfort as required ventilation air is introduced and the latent load is removed. Overall, more studies are needed to monitor long-term performance of the building in use with radiant LTH/HTC to optimize the overall system performance and system design, and to extend its application in different climates and wide ranges of building types.