UV Disinfection of HVAC Systems
Typical UV disinfection systems operate 24/7 at specific intensity; now for first time “automated” UV disinfection systems are applying only the exact amount of UV light required to reduce electrical costs an additional 60-80%
Building owners and operators intrigued by the energy savings and health benefits of UV disinfection systems within the air handler of HVAC systems now have a more compelling reason to take notice.
Namely, recently available “automated” UV disinfection systems that apply only the amount of UV light required based on HVAC usage to deliver an additional 60-80% savings on electrical costs and further reduce an already short 2 year estimated ROI.
UV disinfection systems, which apply ultraviolet light to HVAC air handler coils and the air as it passes through to kill harmful pathogens, have traditionally been static systems that run 24/7 at a specific intensity.
By applying UV light in this manner, building owners and operators win on two counts: clean air handler coils mean the HVAC systems work more efficiently and therefore significantly reduce energy costs; and the building’s occupants breath cleaner, safer air.
Now, by automating the UV disinfection applied to air handler coils to match variable HVAC usage, building owners and operators are saving an additional 60-80% on electrical costs beyond the savings and health benefits already achieved by such systems.
UV Disinfection of Air Handler Coils
The application of UVGI (Ultraviolet Germicidal Irradiation) has been used in healthcare settings for over a century to eliminate surface and airborne pathogens. As a result, the adoption of UV disinfection systems at healthcare facilities with centralized air has been much quicker.
However, despite significant growth in new and retrofit installations in the past 10 years at educational, commercial and governmental facilities, many building owners and managers admittedly are still not clear on what UV disinfection is and how it works. For this reason, the adoption rate has been slower.
Initially, the technology was touted by the industry for its indoor air quality (IAQ) benefits. In fact, numerous studies now available demonstrate that improved IAQ increases the performance of building occupants: it reduces absenteeism, the incidence of respiratory illness, and asthma attacks; and it improves grades in schools.
But it wasn’t until 2006, when the ASHRAE Journal published a study that demonstrated that coil disinfection could reduce electrical costs by 20-24% that the industry had the ammunition it needed to prove that such systems not only could deliver on the health benefits, but also do so with a reasonable ROI.
Left unchecked, HVAC air handler cooling coils can accumulate a bio-film of bacteria, mold, debris, and other micro-organisms. This build-up reduces the airflow along with the efficiency of the heat transfer, causing the HVAC system to work harder and utilize more energy. UVGI light eliminates bio-film and prevents new growth on the coils. As a result, the increased airflow and improved heat exchange can reduce HVAC electrical costs by 20-24%.
In 2008, ASHRAE for the first time addressed UV specifications in its annual handbook. In it, ASHRAE states that the combination of increased airflow and heat transfer “can result in energy savings, which can be significant, with payback of possibly less than two years.”
This estimated ROI is based on an HVAC system operating an average of 60 hours per week. Facilities with higher HVAC demand such as hospitals, hotels, and correctional facilities, often achieve even faster ROI.
The Philips intelligent lamp system is the first major development in the UV industry in decades. UV bulbs have changed little in the past 75 years with the exception of modern bulbs designed around compact fluorescent lamp configurations delivering more output per tube length.
Since automation requires accurate feedback, Philips recently introduced its innovative TUV PL-L Intelligent lamp system, which contains an advanced RFID (radio-frequency identification) chip that communicates lamp data to an automated system.
“Philips’ intelligent lamps can communicate which lamps are on, which are off, the number of times they switch on and off, the number of hours they burn, and when the lamp needs to be replaced,” says David Skelton, President of Safe Air Solutions, a Memphis, Tenn.-based installer-integrator of UV disinfection systems. “Until now, there was no way to communicate this information. The technology didn’t exist.”
However, a lamp alone doesn’t make a system. Lumalier, a recognized leader in advanced UV Germicidal Air Disinfection products for over 47 years, has incorporated the Philips Intelligent lamps into what it calls an Intelligent Disinfection Wall.
As the name implies, it is a virtual “wall” of germicidal UV energy installed near the coils in an air handler that disinfects both airborne pathogens and surface-contaminated coils. The system is created with a variable number of Philips Intelligent Lamps, depending on the requirements of the air handler and its coils.
As part of its system, Lumalier measures HVAC air speed, temperature and fan off/on conditions to only apply the necessary amount of UV energy to disinfect the surface of the coils and the air as it passes for complete disinfection.
Information & Control
“It’s the information and control aspect that is light years ahead of where we were even a year ago,” says Skelton. “What’s unique and really special about the Intelligent Disinfection Wall is that now you know exactly at all times what is going on with your HVAC system.”
Only using the precise amount of energy required for each application can reduce energy usage by approximately 60-80% compared to a static system operating 24/7.
There are further savings and reduced maintenance costs because the Intelligent Disinfection Wall can control which lamps are burning and rotates the load to extend lamp life for additional years of services. The system indicates when to change bulbs to avoid premature changes based solely on scheduled maintenance.
The Intelligent Disinfection Wall is designed to be integrated with existing building automation systems such as BACnet. Many newer buildings use systems like BACnet, which is designed to allow building automation and control systems to communicate with each other in applications such as HVAC, lighting, access control, and fire detection. This enables a facility manager to monitor and control the UV system from a PC, in conjunction with other building automation processes.
To accommodate the many older buildings that don’t have a centralized building automation system, a touch screen near the air handler delivers information on airflow, speed, temperature, and lamp use.
According to Skelton – who installs static systems as well as Lumalier’s Intelligent Disinfection Wall – the energy savings, longer lamp life, and reduction in maintenance offset the additional cost of the automated system when considering a 5 year overall cost of ownership.
Both systems can be retrofitted into an existing centralized HVAC system without disrupting the building’s occupants, and the savings in energy are immediate.
“It’s the right time for budget conscious organizations to look into an automated UV disinfection system,” says Skelton. “Companies that want UV now have a way to pay for it and that’s by the utility savings alone, along with the health benefits.”
For more information, call 800-774-5799 or visit www.lumalier.com.
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