Under actual operating conditions

a closed cooling tower was simulated and the descaling characteristics of an induction-type electronic descaling device and a high-frequency electronic descaling device on the spray water side of an evaporative cooler was investigated experimentally. The results show that both kinds of electronic descaling instruments can accelerate the dissolution of dirt and reduce fouling resistance on the outside of the heat transfer tubes

but the effects are different. During the 150 h of the experiment

the greatest decline in the fouling resistance using the high-frequency and induction-type electronic descaling devices was 17.81% and 20.35%

respectively. With the induction-type electronic descaling device

the fouling resistance reduced several times. The results of scanning electron microscopy show that the structure of dirt crystals is rod-like under the action of the high-frequency electronic descaling device

but exhibits a block structure with the induction-type electronic descaling device. The results of independent experiments show that the two electronic descaling instruments can effectively reduce the hardness of circulating water. After a 12 h experiment

the circulating water hardness was observed to decrease by 40.35% and 37.04%

respectively.