Design method of natural cooling source adopted in transition seasons

Based on the switching temperature calculation between the mechanical ventilation and the air conditioning system operation, presents the design and energy efficient evaluation methods of natural cooling source, reducing the energy consumption of fans by applying ventilation rate control scheme in transition seasons. The system is adopted in a large space factory building in Shanghai, and the annual energy consumption of the main chiller is 29.3% less than that of the system adopting air conditioning in transition seasons on condition of load rate 0.8, and in unloading control mode the fan consumes only 41% to 56% energy of that in full load operation mode in yearly operating air conditioning system. Holds switching the operation modes between the air conditioning and the mechanical ventilation according to the given date, and quantitatively analyses the relation between the allowable failure rate and energy efficient rate.