Energy Efficiency of Chillers Improved by 16.0% 

Background

There are two fresh water cooled chillers generating 400TR cooling capacity to part of a commercial building. The rest of the cooling power is provided by over 1200TR air cooled chillers.

Commercial chemicals such as biocide, scale and corrosion inhibitors are used in the condensing water. Automatic bleed-off is set to 1,500 ppm ofTotal Dissolved Solids (TDS). Mineral scale deposit was coated on the tubes which required annual tube cleaning to restore the cooling power.

One of the chillers was limited to operate at a maximum of 75% of the full load due to the scaling accumulation which increases the condenser pressure and may trigger the high temperature shut off.

In order to improve the coefficient of performance (COP) of the two chillers and restore the cooling power of them, Hydropath technology was installed. The condenser tubes were inspected and the condition is shown in Picture 1 before activating the HydroFlow.

Result

After 6 months of operation, the condenser cover was dismantled for tube inspection. Existing scale in most area was dissolved as indicated in Picture 2.

The chiller that was limited to 75% of full load was able to operate at full operating capacity.

The data analysis showed a reduction of 16.0% energy consumption in the chiller and eventually a 2.5% - 3.0% reduction in electricity costs were captured. The Return on Investment was realized in 20 months.

An additional benefit of the installation is the improved condensing water quality with total bacteria count and Legionella count controlled well below the limit.

 
                                                    Picture 1 - Original Condition after initial cleaning

                                                    Picture 1 - Original Condition after initial cleaning

                                           Picture 2 - After HydroFlow operation of 6 months

                                           Picture 2 - After HydroFlow operation of 6 months