The discussions about how to fight climate change are increasingly focusing on energy efficiency measures to reduce greenhouse gas emissions from buildings. The HVACR sector has been estimated to consume about 17% of the world’s generated electric. One expert recently stated his belief that 30% to 40% of building energy goes to refrigeration with 20% to 30% going to HVAC (with lighting consuming 15% to 20%). Clearly, maintaining HVACR equipment in tip-top shape so it runs with maximum energy efficiency will insure less waste of electric with reduced demand and consequently lowered indirect power plant GHG emissions. The HVACR tradesperson can rightly claim to be a warrior in the broader fight against climate change.
A recent knowledge brief issued by the Kigali Cooling efficiency Program puts some numbers on impact that cleaning and maintenance likely will have on energy savings. In Figure 1 it estimates the emission reduction opportunity due to lowered electricity demand from better cleaning and servicing at a value that comes in at a 19.2% savings level. Stated differently, the Director General of an international refrigeration institute stated his belief that better optimization, monitoring, and maintenance of cooling equipment might contribute a further 38% savings on top of those delivered through the planned phase down of high global warming potential refrigerants, which is a push getting increased notoriety in climate change circles these days.
In our niche area of refrigeration condenser coil cleaning, there is some actual data supporting the numbers mentioned in the Kigali document. Several years ago, a field survey was conducted showing the effect of doing coil cleaning on a small number of reach-in freezers and refrigerators (see p. 10). While there was wide variation in the energy savings from doing coil cleaning (from about 3% to about 50%), the average value was 17%, which is close to the about 20% value stated in the Kigali document as their average. Non-published before and after data on the more fouled units showed energy savings ranging from about 2000 to 5700 KwH/unit/year with the percent savings tightly packed at 46% to 50%. From these data, we ourselves are using the 17% savings value and 1250 KwH/unit/year as rough estimates of savings stemming from coil cleaning of commercial and institutional “coolers.”
Certainly, the foregoing presents one of the main reasons to service/maintain both refrigeration units and air conditioning systems/units with coil cleaning, filter replacement, and the like. Energy savings that might average about 20%, and could be much higher, is a tangible and powerful result. Those savings go right to the bottom line. Additionally, there are equipment operational advantages too since the units will operate as designed with less stress on the compressor and other components in the appliance:
There will be a likely reduction in emergency service calls if maintenance protocols are followed. For example, it’s been stated by one HVACR refrigeration expert that quarterly coil cleaning virtually eliminate emergency service calls traceable to clogged coils;
For refrigeration units, the cooled or frozen inventory will also be safeguarded since the appliance operates within designed parameters; for AC systems, the building occupants will benefit with enhanced comfort;
Servicing and maintenance, as described in the owner’s manual, is likely to also prolong the life of the equipment; and
For the coming wave of units running on flammable hydrocarbon refrigerants (such as R290), clean coils might allow the units to run at lower pressures and temperatures which would be a potential safety benefit.
So, when faced with multiple coil units in need of cleaning, how best to do it both quickly and effectively? Brushing and vacuuming the surface of the coil structure will remove surface contamination by dust and debris. It won’t address the problem of deeply embedded contamination within the interior of a typical commercial refrigeration coil unit. Specialized coil cleaning brushes are promoted as a means to get at such deeply embedded debris. However, their use will greatly prolong the time needed to do the cleaning task.
Experienced HVACR techs, when faced with the need to clean a coil on a reactive service call, will generally resort to a blast of compressed air to quickly and effectively blow out the clogged coil. To prevent generation of an unwanted dust cloud that would pollute the surrounding area, a wet cloth or towel is usually draped over the back surface of the coil to catch the blown off debris. This method has drawbacks. The wet fabric item might fly off during the cleaning unless it is securely affixed to the coil unit. Even if it stays in place, the tech often has a thoroughly contaminated item that might not be useable for additional cleanings of this type. Luckily, there is a better approach using a unique dust containment hood that solves these problems.
The COILPOD® dust containment hood (pictured above) is an environmentally-friendly solution for the indoor, compressed air cleaning of such condenser coil units in plug-in cooling appliances of various types. A person desiring to clean the condenser coils contained in such appliances first places the COILPOD® hood (approx. 20” [50 cm] wide x 14” [34 cm] deep x 19” [48 cm] high) over the coil structure and then simultaneously supplies compressed air and vacuum, for example, from a standard wet/dry vacuum, through two ports in the bag’s surface to remove debris from the coils while vacuuming it out of the bag. The bag effectively entraps the removed debris during the cleaning operation protecting the environment outside the bag from undesired contamination. The company’s website contains full details on this new device and has an online store for its purchase. The product was designated as a “best practice” tool by the Professional Retail Store Maintenance (PRSM) Association in 2014.