Multiple kinds of renewable energy surrounding a building will be exploited by an originally developed heat pump system named the ReGL, and it was applied to a testing building called the RE house. The system consists of a water loop that connects to ground heat exchangers, i.e. a ground loop, with which the sky-source heat pump (SSHP), water-source heat pumps (WSHPs) for HVAC, floor heating, and domestic hot water exchange heat. The ReGL system can collect ground heat, solar heat, and heat content of outdoor air. The same system make uses of nocturnal radiation, outdoor air, and evaporation of rain for heat dissipation.

Desiccant cooling system has been considered to be a suitable system to improve IAQ (Indoor Air Quality) by its superior performance of humidity control, and decrease the health risk due to mold growth. The purpose of this research is to estimate the possibility and methods of combining desiccant cooling system with heat pump that can improve its energy efficiency at the same time.

Recently, using natural energy have been proposed and applied to achieve energy conservation in buildings. The concept of this system is utilizing both natural ventilation and radiation panel cooling, to introduce outdoor air into the indoor thermal conditions by the power of nature as far as possible. Radiation panel can be used in case of that outdoor air temperature is higher than that of indoor, and the energy conservation and dehumidification is possible by using this system.