In order to quickly evaluate the attenuation rate of the heat transfer capacity of heat exchangers used in air-conditioners after long-term operation

a method for predicting this attenuation rate is established by measuring the heat transfer capacity of a heat exchanger before and after dust-accelerating tests. In this test method

the dust concentration on the windward side of the heat exchanger is accurately adjusted by using the negative feedback mode

which can maintain the stability of the dust concentration on the windward side of the heat exchanger during the dust-accelerating testing period. The placement of the heat exchanger sample can be fixed during the dust-accelerating and heat transfer capacity tests by combining the dust box and air duct. The reliability and repeatability of the test method are verified under the condition of inlet air temperature of 45 °C

air flow rate 1.5 m/s

inlet water temperature 21 °C

and water flow rate 0.5 m/s. The results show that the dust concentration on the windward side of the heat exchanger can be maintained at the target value of 120 mg/m3 and the fluctuation range is within ±20%. The heat transfer capacity attenuation rates of four types of heat exchanger samples with different structures are measured several times

and the relative deviations of the attenuation rates are within ±10%

implying that our test method has good repeatability.