Coil Cleaning – Exciting? No… Important? Yes!Billy Pell
As commercial building owners and facility-maintenance professionals prepare for the dog days of summer 2017, it is critical they make sure their evaporator coils are clean and ready to perform!
An article in a recent issue of HPAC Engineering, quotes Tim Kane, president and chief executive officer of maintenance-solutions provider Goodway Technologies: “Not only do you want to make sure your HVAC system is running properly, but uncleaned coils can shorten the life of your equipment and force your system to work harder than it should, thereby drastically increasing the cost of running your HVAC.”
An article in Buildings Magazine agrees…One of the easiest, most cost-effective green things you can do for your building’s energy efficiency is to have your HVAC system’s condenser and evaporator coils inspected yearly and cleaned as necessary. Dirty coils force compressors to run longer and work harder than required, increasing energy usage and utility costs while decreasing component life and occupant comfort.
According to the U.S. Environmental Protection Agency (EPA), the U.S. Department of Energy (DOE), major utilities, and other experts, dirty condenser and evaporator coils can significantly increase HVAC energy usage and associated utility costs. The U.S. DOE says “a dirty condenser coil can increase compressor energy consumption by 30%.” A dirty evaporator coil decreases airflow, resulting in reduced heat transfer and a degradation of the dehumidification process. These can cause overall air quality to decline and systems to fail, and decrease the life expectancy of motors due to increased heat while running.
ASHRAE Study Confirms
All across the internet you can find scores of articles and blog posts extolling the virtues and importance of coil cleaning, but perhaps none is more persuasive than the findings revealed in the November 2006 ASHRAE Journal article titled, “Study Verifies Coil Cleaning Saves Energy.” Authored by Ross D. Montgomery and Robert Baker, the article reports the results of a coil cleaning study performed at the iconic 34-story Times Square skyscraper, 1500 Broadway in New York City.
Although it’s theoretically known that cleaning a coil can result in energy savings, little actual testing data and research exist to prove the point. As a result, building managers often ignore or reduce resources devoted to air-handler maintenance when faced with budget constraints. If proper maintenance is an important consideration in overall energy costs, conserving in that budget area can be self-defeating.
The study was conducted in July through September 2005 by restoring two of the four air handlers in the 1500 Broadway building – then comparing their performance to the other two.
“Restoration of [just one of the] air handler[s] resulted in improvements that will lead to energy savings of up to $40,000 this year.” And there were other results beyond the monstrous energy savings… including decrease in pressure drop and increase in airflow, increase in thermal efficiency of the cooling coil, decrease of the load on the chiller plant, and increase in efficiency of heat transfer.
The authors of the study concluded, “In addition to the hard results presented in this article, many other ‘soft’ positive results come out of cleaning and normal maintenance operations and its resultant energy savings and airflow increases. The HVAC system performance is increased and can more closely perform to its original intended specified operation… After coil cleaning and regular maintenance, the HVAC systems are cleaner, and do not provide the environment for fungal, bacterial and microbial growth in their coils, ducts, and pipes. IAQ and the awareness of good IAQ are increased in the building, and the overall comfort and work effectiveness can be greatly enhanced. Overall tenant satisfaction with the building environment has been improved as evidenced by the property manager’s communications and positive feedback.
“Furthermore, not only will the owner benefit from the obvious energy savings and comfort increase, we also were able to help optimize some other building maintenance and processes and help enhance energy and maintenance effectiveness for years to come.
“…Good maintenance and operation practices including coil cleaning can significantly improve energy efficiency and IAQ performance of the HVAC&R systems in a building, such as reported here of 10% to 15%.”
Goodway Technologies Coil Cleaning Checklist
One of the quickest and safest ways to maintain your system is through a comprehensive coil-cleaning program! Goodway Technologies recently released a checklist:
1. Obtain the best possible access
Cleaning coils works best when a maintenance technician can get the cleaning wand close to the areas that need to be cleaned. Consider using flexible wands if access is difficult.
2. Vacuum coils and fins
Before cleaning, remove dry debris from coils with a vacuum that can reach dust and dirt in tight spaces. Other options include using compressed air.
3. Clear blockages
Condensate pans and lines need to be free of blockages before wet cleaning can begin, as any obstructions can cause major damage from flooding and because of HVAC-system condensate. Consider a wet/dry vacuum to remove any debris prior to cleaning.
4. Use a wet cleaning process
Pressurized water forces deeply embedded dirt and debris to come loose, vastly improving the cleaning process.
5. Use a powerful-yet-delicate cleaning system
High-pressure equipment can damage fins, especially on evaporator coils. The ideal system should deliver 125 to 200 psi and up to a half-gallon of flow per minute.
6. Apply an alkaline non-caustic cleaning foam
Use of a non-caustic cleaner helps to protect coils from corrosion.
7. Apply a mold-control agent
Adding a mold inhibitor that is U.S. Environmental Protection Agency-registered and approved for use in occupied spaces can help to keep coils clean and free of odor and allergy-causing mold and mildew.
This post includes excerpts from three articles: “Goodway Issues HVAC Coil-Cleaning Checklist” from HPAC Engineering, June 13, 2017; “Clean HVAC System Coils Save Energy” from April 2009 Buildings Magazine; and “Study Verifies Coil Cleaning Saves Energy” published in the ASHRAE Journal in November 2006.