Performance monitoring of direct air-cooled power generating unit with infrared thermography

Infrared thermography technique was employed to monitor overall as well as local surface temperature distributions of air-cooled condensers (ACC) in order to investigate the influence of ambient air temperatures, surface fouling of fin-tube bundles and natural wind on performance of air-cooled power generating units. Three typical direct air-cooled power generating units in operation in north China were selected as the research objects, which are 300 MW sub-critical units with ACC of three-row fin-tube bundles, 600 MW sub-critical unit and 600 MW supercritical unit with ACC of single-row fin-tube bundle respectively. The monitoring results revealed that the counterflow ACC units were vulnerable to freezing in winter. The results also cast light on the uneven steam flow distributions inside fin-tubes of different parallel-flow ACC units, especially when the redundant cooling areas of ACC Island were large. The characteristics of surface temperature distributions were obtained in different regions of ACC units under surface fouling conditions. It was also acquired that the gentle natural wind can have an impact on the heat transfer of most cooling areas of ACC island by forming overhead vortex. This should be paid attention to as well as besides the effect of thermal recirculation under large natural wind conditions. The present study may benefit the optimal operation of air-cooled power generating units.