Background

There are six seawater cooled chiller generating 6000TR cooling power to a government hospital. Serious mineral scale was deposited on the condenser tubes in the past due to the use of seawater cooling towers.

Chlorine is used to minimize the development of biological fouling caused by the growth of micro-organism and macro-organism. However the accumulation of mineral finally transformed into hard scale on the condenser tubes. The condition could not be prevented even though the bleed-off rate is set to four times a day and half an hour each time.

Condenser tube cleaning was required twice every year with hydrochloric acid. Although the tubes are made of titianium and will not be attacked, the down time and energy efficiency of chillers are the major concern.

In order to improve the situation, AquaKLEAR is installed. To establish a baseline for the performance of chillers, condenser tubes of one chiller were inspected and is recorded in Picture 1. Mineral scale was heavily coated on the tube surface.

Result

After 2 months of operation without a pre-cleaning of condensing tube, the condenser cover of the chiller was dismantled for tube inspection again. The actual operation time of the chiller was three weeks because it was in the winter. Hard scale was softened and could be easily wiped away with a piece of tissue and finger as shown in picture 2.

From the data log, the performance of chillers is improved by 9.6% and the investment is paid back in 19 months based on the actual load profile.