A revised degree hours evaluation method for energy saving potential of free cooling systems

Abstract

In order to make full use of outdoor free cooling sources to reduce building air conditioning energy consumption, accurately evaluate the potential of natural ventilation, and guide the selection and utilization of more free cooling systems, a revised degree hours method was proposed to evaluate the energy-saving potential of different free cooling methods. The conception and rationality of the method are indicated by comparing with the degree hours method. The free cooling system model was built by using TRNSYS software to analyze and verify the rationality of the calculated result of revised degree hours. The results show that the revised degree hours can take into account the heat exchange temperature difference and heat exchange efficiency, and there is a direct relationship between the revised degree hours and the system energy saving. It can compare and evaluate the application potential of different free cooling methods, guide the selection of different free cooling methods, and help the low-carbon development of refrigeration and air conditioning systems.

Keywords

• natural energy
• free cooling
• revised degree hours
• building energy efficiency
• ventilation and air conditioning