EXPERT COLUMN: America’s ‘Dirty Little Secret’

Retail food establishments of all types contain refrigerated display merchandisers for a wide variety of foods and beverages, drugs and flowers, as well as other refrigerated products. Manufacturers of these units often recommend that their condenser coils be cleaned on a regular basis (usually monthly), but most owners probably fail to perform such maintenance.

The units run without regular cleaning, even though the coils collect dust and debris compromising their heat transfer efficiency. The results: an increase in energy cost (often as high as 15 percent to 20 percent); a less green store environment; decreased equipment life due to prolonged unit run time; an increased chance of equipment failure, since the unit runs hotter and at higher pressures; and a loss of optimal cooling capacity, increasing the chance of food spoilage.

There’s an apparent lack of recognition of the benefits of regular condenser coil maintenance, even by the experts. The Department of Energy, in its extensive September 2009 report, Energy Savings Potential and R&D Opportunities for Commercial Refrigeration, failed to mention a regular condenser coil-cleaning protocol as an important strategy to follow. Instead, the report focused on redesigning certain components of the appliance unit to a more advanced, energy-efficient design. The report is silent about realizing energy savings and other benefits from a regular cleaning program for the condenser coils, even for units now in place.

We conducted trials to determine what a modest cleaning protocol for the condenser coils in six delicatessen refrigeration units would accomplish in electrical energy savings over a one-year period. The coils were cleaned only every three months, which is less than the monthly cleaning advocated by many manufacturers. Despite this more modest schedule, a yearly electrical savings of about $821 (about 6 percent) was realized for the six units, the electric rate at 16 cents per kilowatt-hour. An additional savings was four fewer service calls on these units, leading to another $265 in savings. A three-month cleaning protocol on a single 8-foot ice cream merchandiser, running at a lower temperature, produced more impressive electrical energy savings: $228 (about 16 percent), with the electric rate at 12 cents per kilowatt-hour.

The conventional manner for the cleaning of such condenser coils is described in "Dusting Commercial Refrigeration Condensers" on the Foodservicewarehouse.com website. This article says that such cleaning should be performed by a “two-person” team using a wet/dry vac with a vacuum port and an exhaust port. First, one member of the team vacuums the coils to remove the more accessible dirt and debris. Next, a hose is connected to the exhaust port of the vacuum to blow air into the condenser unit, dislodging dust and debris in the interior of the unit. A receptacle (such as a box) containing a damp capture medium (such as a damp cloth or towel) is held by the second team member at the other end of the unit to catch the dislodged debris.

Recently, the previously described box/damp cloth technique has been improved by the development of containment bags. For example, the ProVacSac bag is a triangular cloth containment member with an open base adapted to fit over one open end of the condenser coil unit and an opening at its apex to accommodate a vacuum tube. A stream of condensed air is supplied into the unit from the other end to dislodge dust and debris from the unit during the cleaning operation. The retail price for differing sizes of these products ranges from about $80 to $130.

Of differing design is our COILPOD dust containment bag, retailing from only about $35 to about $55, depending on model and vendor. The website shows this bag as having an adjustable opening that completely fits over the condenser coil unit. The bag’s transparent front panel contains two holes, one for accommodating the hose from a wet/dry vac, and the second the exhaust air hose from that device. A stream of air from the vacuum, provided through the latter hose, dislodges dirt and debris from the condenser coil unit, with the bag containing the airborne particulates, while the vacuum hose removes them from the containment bag into the vacuum.

Setting up a regular cleaning program for your condenser coil units will provide currently unrealized energy saving and other benefits for your store’s operations.

Jake Steinmann is the owner of a convenience store, with 18 years’ experience in the retail food industry. He developed the COILPOD dust containment product as a way to improve the cleaning of the condenser coil units in his store. Contact: [email protected]. Richard Fennelly is a retired intellectual property attorney and the current development director for the COILPOD commercialization effort. Contact: [email protected].