Abstract: When the fresh air conditioner uses the exhaust ventilation function in a low temperature environment, it is easy to cause condensation icing and blockage in the exhaust duct, which affects the ventilation effect and service reliability. Therefore, it is of great significance to study the improvement and prevention of condensation icing in the exhaust duct. Based on the formation principle of condensation and icing in exhaust pipe, a set of operation prevention and control logic is proposed to predict the risk degree of condensation and icing through the calculation and comparative analysis of the temperature of exhaust pipe inner wall. Experimental verification shows that only a small amount of condensation and icing are produced in the exhaust duct during the outdoor -7℃ exhaust function test for 8 h, and the reliability is significantly improved.

Key words: Exhaust air, Low temperature, Reliability, Fresh air conditioner