Hennigan Engineering Reveals Surprising Cost Saving Figures of Maintaining Chiller Efficiency
Facility Managers, Maintenance Personnel and Engineers recognize the problems caused by scale in water systems; increased maintenance, unplanned shutdowns, premature replacement of equipment and higher energy costs.
Thin layers of scale can form in a Chiller’s tubes, decreasing the efficiency (heat transfer) of the heat exchanger resulting in increased energy costs. The thermal conductivity of calcium carbonate is 4,000 times less than that of copper and therefore, even the thinnest coating acts as an insulator reducing the heat transfer, decreasing efficiency.
Scale in the Chiller tubes causes an increase in the head pressure, resulting in a substantial increase in energy consumption of the compressor. Chiller equipment manufacturers agree that just a 0.04inch (40 thousandths) thick scale buildup on the heat exchanger tubes of a 500 ton Chiller results in $37,000.00 extra on the electrical bill. The larger the Chiller, the more energy wasted: the same 40 thousandths scale thickness in a 1200 ton Chiller could add $90,000.00 to the electrical bill!
Table showing the costs savings for tube cleaning and maintaining chiller efficiency.
Most Chiller installations experience problems and have difficulty with peak demands during summer months. Unfortunately, most of these installations have no room to install a larger Chiller and therefore they have to accept that on days of high humidity, when cooling towers become less effective, the compressors are liable to trip off on high head pressure – stopping the function of the Chiller just when the need is the greatest.
Historically, mechanical cleaning has been the means of tube scale removal. Unfortunately a thin layer of scale still coats the Chiller tubes and can also cause cathodic cells due to inconsistent cleaning leaving clean areas as well as dirty areas. The resulting cells cause corrosion and pitting leading to tube failure.
High Pressure Water Jetting (Hydrolasing) up to 20,000 psi has been shown to be extremely effective in FULL scale removal without streaking (clean area vs. dirty area) and without any damage to the tube substrate. We have seen head pressure reduction of 15psi to 20psi after cleaning with this method.
Since there is commonly only a 50psi differential between low load and full load, this pressure reduction after Hydrolase cleaning greatly reduces operating costs and increases the efficiency of the chiller.
In addition to the obvious energy savings and costs associated with inefficient Chiller operations, a substantial reduction of millions of tons of CO2 generation that is associated with refrigeration is also achieved.
With the experience and expertise of Hennigan Engineering in the utilization of Hydrolasing Chiller tubes a substantial savings can be achieved. We look forward to the opportunity to support your Chiller cleaning needs.