The Simplest Way to Maintain Chiller Efficiency

Chillers in large commercial buildings are often the most expensive piece of equipment in the facility. Not only is a chiller expensive to purchase and install, but according to the North Carolina Energy Office’s “Chillers: Energy Saving Fact Sheet”, chillers “consume more than 50% of electrical energy during seasonal periods of building use.” So with a very expensive, very energy-hungry piece of equipment you might think facility managers spend a lot of time ensuring chillers work at peak efficiency. But the same fact sheet points out that a Department of Energy survey estimates that “120,000 chillers in the U.S. are expending more than 30% in additional energy through operational inefficiencies.” It seems a lot of chillers are wasting a lot of money through operational inefficiencies. But what exactly is an operational inefficiency and how can facility managers correct these inefficiencies?

A chilled water system works by removing heat from the interior of a building and transferring that heat to the outside. Heat moves from inside the building, into the chilled water piping, to the evaporator side of the chiller refrigerant circuit, next to the condenser side of the circuit, and if the chiller is water-cooled, the heat has the extra steps of moving into the condenser water and finally out of the cooling tower. Building heat has a lot of steps and substances to pass through before the heat finally makes it to the outside atmosphere. Because the system is so dependent on the transfer of heat from one place to another, anything that inhibits the efficient transfer through the system is an operational inefficiency.

Keeping tubes and chiller components clean is the simplest way to maintain efficiency throughout the chilled water system. Read any operation and maintenance manual for a chiller and you’ll see the importance of cleaning the equipment highlighted throughout the document. The operation and service manual for Carrier’s Aquaforce Air-Cooled Liquid Chiller is a good example of how manufacturers reinforce cleaning to ensure proper equipment operation.

For chilled water tubes within the chiller itself, Carrier’s manual recommends to “[i]nspect and clean cooler tubes at the end of the first operating season. Because these tubes have internal ridges, a rotary-type tube cleaning system is necessary to fully clean the tubes.” Goodway’s RAM-5 Tube Cleaning Kit is a good option for technicians. The internal ridges they are referring to are also called “enhanced tubes” and are designed to promote heat exchanger efficiency through more surface area. However, when they get dirty with mud, slime and other contaminants, it has the opposite efficiency impact. The RAM-5 is a stainless steel tube cleaner with a trigger controlled flexible shaft to give operators precise control of the cleaning brushes so they can “dial” in speed and feed options as they move through the tube. The RAM-5 has a simultaneous water flush that pushes debris out of the tubes as the brush scrubs the inside surface. Even more, the kit comes with 25 extra brushes, a second flexible shaft, and a chiller bib to keep water and debris contained during the cleaning.

Chiller tubes are not the only part of the chiller needing regular cleaning and maintenance. Carrier’s manual also describes how to clean the condenser coils on its air cooled chillers. “Routine cleaning of coil surfaces is essential to maintain proper operation of the unit. Elimination of contamination and removal of harmful residues will greatly increase the life of the coil and extend the life of the unit.” As such, consider equipment with a vacuum and coil cleaner integrated into once machine. Goodway’s CoilPro® High Flow Coil Cleaner w/CoilVac or CC-600-KIT has a Dry HEPA vacuum for removing large debris and dust from inside and around the chiller as well as a coil cleaner for penetrating thick condenser coil beds. To avoid damaging condenser fins, Carrier warns that water pressure for coil cleaning should “not exceed 900 psig”. The CC-600-KIT lets technicians select 300 psi or 600 psi water pressure to protect the coils while providing a solid 1.6 gpm of water flow to wash away debris.

The CC-600 comes with a 4 HP vacuum motor with a 2 quart capacity for the vacuum side and a 5 gallon internal water tank. An external water connection is not required because cleaning water is stored in the CC-600’s tank. With the CC-600, vacuuming and wet cleaning can all be done with one machine saving the time and effort of having to move two pieces of equipment from chiller to chiller.

Chillers account for as much as 50% of a commercial building’s energy use. With that kind of expense month after month, year after year, facility managers have a responsibility to keep their chillers running as efficiently as possible. Part of regular chiller maintenance is cleaning the coils and removing the debris that inhibits the transfer of building heat through the chilled water system. Building maintenance staff partnering with Goodway Technologies can find the right equipment to keep chillers clean, working efficiently, and the inside of their buildings cool.

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