Sponge-ball automatic tube cleaning device for saving energy in a chiller

The first sponge-ball automatic internal tube cleaning system, normally used for large heat exchangers in power plant applications, has been installed and tested in a seawater-cooled chiller in Hong Kong. The tests were thoroughly conducted under various weather conditions, cooling loads, and fouling conditions, in comparison with an identical chiller operating without a cleaning device. The low fouling factor maintained by the sponge-ball system is reflected by the small temperature difference between the condensing refrigerant and the condensing water outlet, ranging from 2°C and 4°C depending on the cooling load. Without a sponge-ball system, the temperature difference is typically between 5°C and 11°C. The sponge-ball system improves the overall coefficient of performance (COP) by 12%. An economic analysis shows that the payback period is within 3 years.