Freshfields Bruckhaus Deringer LLP is a multinational law firm that takes its environmental commitments seriously. With its headquarters in London, Freshfields has 28 offices located in 17 jurisdictions across Asia, Europe, the Middle East and North America and employs over 2,500 legal advisers that work with governments, multinational corporations and financial institutions.
One of the company’s goals is to improve its environmental performance in a cost effective way. Each office has clearly defined responsibilities aimed at lowering its carbon footprint and tackling climate change.
As well as adapting working practices and minimizing waste and resources, Freshfields invests in energy efficient technology. Following trials with RAB Specialist Engineers, building maintenance firm Norland Managed Services installed 16 air intake filter screens at its New Bridge Street headquarters in Blackfriars, London. The aim was to help reduce its energy consumption and ensure the building’s HVAC equipment worked effectively.
To prevent airborne debris from clogging existing filters and potentially damaging cooling coils, Stacey Collins, health, safety and environment manager for Freshfields, required a solution that would ensure the fresh air supply, which is drawn in through external weather louvers, was maintained at optimum levels and prevented the HVAC equipment from having to draw more energy than was necessary due to restricted airflow levels.
Air Intake Solution
John Nicoll, contract manager with Norland Managed Services commented: “We were also interested in trying these particular air intake filter screens because the existing filters were becoming clogged with debris very quickly and required changing every 14 days. The initial trials have performed very well and are helping us to maintain efficiency and reduce maintenance times, in addition to protecting the cooling coil from airborne debris.”
Prior to the installation of the new screens, it was evident that while the existing filter frames were in good condition, the original filter media had failed to prevent debris from passing through to the coil. As the existing media became contaminated (muck) the system was requiring more energy to draw the air supply into the coil (brass) resulting in a site engineering team having to change the air filter media every two weeks. As the saying goes, ‘Where there’s muck, there’s brass,’ only in this situation the muck wasn’t generating money, it was wasting it due to the cost of frequent maintenance schedules and energy inefficiency.
To prove the effectiveness of the air intake filters, Richard Betts, managing director of RAB Specialist Engineers, agreed to carry out a comparison test. Half of the cooling coil was protected using the older existing filtration media, while the other half used the new PreVent screens manufactured by Permatron in the US.
An airflow test, carried out by Stacey Collins, recorded the following data:
Existing filter media 0.5m/s
PreVent air intake screen 0.7m/s
This difference of 29% meant that the fan speed could be significantly reduced to achieve the same air volumes through the coil, and with a speed reduction of only 20%, a 50% reduction in energy demand can be achieved.
After two weeks the original media was clogged and required replacement. Although this was a low cost product, the additional fortnightly labor and waste disposal costs meant that this was proving to be an expensive operation to maintain.
Although the new filter screens were also very dirty, the innovative magnetic fixings allowed them to be easily removed, cleaned and replaced without the need for waste disposal. Furthermore, the screens provided improved particle retention and increased efficiency.
Air Intake Filter Return on Investment
The Freshfields trials have further proved the effectiveness of lowering energy demand, reducing expensive maintenance costs and optimizing HVAC equipment.
Data from the trials has enabled RAB Specialist Engineers to calculate costs and the return on investment. The results suggest that payback in just two years could be achieved for this particular project.