We are often asked does cleaning a coil save energy?
The short answer is yes, coil cleaning does save energy and it is worthwhile.<
Coil Cleaning Saves Energy. We believe it is even more relevant today
what with Eskom’s sky- rocketing energy costs.
This study looked at air handling units (AHUs) before and after coil cleaning
to see what impacts coil cleaning had on energy savings.
Three key variables that added credibility to the study:
- The AHUs were large enough to provide substantial data (both units over
- The AHUs were constant volume (not easy to find these days). It would
have been difficult to quantify energy savings on Variable Air Volume (VAV)
- The weather data was constant during reporting periods. The study looked
at a huge building [34 stories] in downtown New York.
See the following results and conclusions:
- Cleaning the AHU SF9 coil resulted in a decrease in the pressure drop
across the coil, of approximately 14%. This resulted in a corresponding
increase in airflow.
- Cleaning the cooling coil in AHU SF9 resulted in an increase of 25.3%
tons of cooling (on prior 81 tons of cooling). They estimated that 100
tons (352 kW) of cooling capacity would be added to the building once all
four AHUs coils were cleaned. (Building had a total of 1,800 [6330 kW]
tons available capacity.)
- Cleaning the cooling coil increased the thermal efficiency of the cooling
coil 25% with respect to its ability to transfer its energy to its sensible
loads (10% with respect to latent loads).
- Cleaning the cooling coil would continue to save energy by decreasing
the load on the chiller plant, and making the heat transfer of this loading
more efficient. It reduced the time of multiple chiller operation and its
associated pumps, cooling towers, chemical costs, wear and tear, etc.
- Restoration of the one air handler resulted in improvements that will
lead to energy savings of up to $40,000 this year, in accordance with the
results and assumptions of this study.
- After coil cleaning and regular maintenance, the HVAC systems are cleaner,
and do not provide an environment for fungal, bacterial and microbial growth
in their coils, ducts, and pipes.
- Overall tenant satisfaction with the building environment has been improved
as evidenced by the property manager's communications and positive feedback.
- Conclusion: Good maintenance practices, including coil cleaning, can
significantly improve energy efficiency (by as much as 10% to 15% as in
We have an excellent example of a similar programme closer to home: Gateway
- Ken Davidson, one of South Africa's outstanding Retail Facilities Managers,
and a pioneer of the Going Green campaign in shopping malls, was the Senior
Facilities Manager at Gateway – one of the country's largest shopping malls
– where the trials were done.
- Ken has developed a similar programme to the one above. His findings
were that the pristine condition of the AHUs, in addition to the latest
in chiller technology, which they had installed at the complex, contributed
to a saving of 10% of their monthly energy bill of R6,000,000. That's a
massive R600,000 per month.
- • Ken estimated that 30% of the R600,000 can be attributed to O3 chemicals
– a saving of R180,000 per month.
- Jonathan Hansen is the SFI Group Site Manager. He and his team continue
to drive the O3 Going Green programme at Gateway. They use a 1:1 dilution
of the chemicals once a year, and a 1:15 dilution whenever they find any
dirt in a coil.
- And SFI Group spends just R55,000 on O3 chemicals for the entire year
to achieve these results!
- In addition, the O3 Going Green programme introduces a whole new way
of cleaning AHUs, evaporators and condensors by using the latest Trade
Air Oil Free compressor technology, which enables the Contractor to improve
cleaning times, and dramatically reduce the quantity of water used to rinse
down. In the case of evaporators and condensors, no water is required at
- Furthermore, downtime has almost been eliminated.
- As was the case in New York, the tenants are happy because their customers
can shop in comfort, despite Umhlanga's sky-high humidity in summer.
- It's a no-brainer. This proves that Going Green doesn’t have to be expensive!