Over twenty years ago HVAC systems first began getting outfitted with UV-C light systems to irradiate the coils, keeping them clean and operating at peak efficiency. Even if cleaning HVAC coils is a task done regularly at your facility, most often paybacks have been 3-9 months (even in the cooler climate of the Upper Midwest). This fast payback and an ever increasing effort to reduce energy costs has led to many companies promoting UV-C technology heavily. With all these companies offering what they claim as “the best” solution determining what system offers the highest value to your facility can be a difficult task. To help with that difficulty, use of the following checklist will make sure your project goes smoothly and doesn’t “lock” you in to a certain manufacturer – making finding replacement parts much more difficult and expensive.
There are 5 things to consider before starting a UV-C for Coil Irradiation project:
1) Determine Baseline This is something that gets skipped a surprising amount of the time, and can indicate what air handlers are in the most need of UVC and which ones may be functioning fine without it. What should be recorded is the static pressure across the cooling coil, the incoming and exiting temperature of the water, the incoming and exiting air temperature, and the relative humidity. Having these values will allow you to compare the current performance to what the system’s original design was, and then how much of a gain in efficiency was realized after installation of the UV-C light system.
2) Proprietary Components It’s no secret or surprise to most of us when we learn companies design components that will force you to go back to them for replacement parts. Having a unique ballast, silly fixture, or proprietary lamp plug can seem like a minor thing at first, and the salesperson will likely tout this as an advantage, but it can make sourcing replacement parts near impossible and expensive, for wxample the price of replacement UV-C lamps can be double of their commercially available counterpart. There is no reason to have proprietary ballasts or lamps when doing Coil Irradiation. By using systems that only use commercially available parts your ongoing maintenance costs will be as low as possible because you get the benefit of competition of multiple suppliers all wanting your business. Without doing this the replacement UVC lamps from the OEM can be double or triple the price of their commercially available replacement uvc lamps.
3) Lamp Watts/sq’ of Coil This number will cut through a lot of the “sales” talk when you have competing companies saying their system has “higher-output” or claims that a system’s lamp/fixture is “more powerful.” There is a lot of information given to end-users to confuse this issue, or at least muddy the water. By breaking it down to the lamp watts per square foot of coil you get a simple and accurate figure for comparing competing systems.
4) Installation and Operations Manual The amount of time to install the system impacts the initial cost of the system, and installation time can vary greatly between manufacturers. This will also show you how difficult it is to replace the lamps/emitters when the time comes, and how much new equipment (fixtures, lamps, supports, etc.) will be installed in the airstream. Needless to say, the less in the airstream the better so it doesn’t impact the air pattern or internal static pressure of the air handler.
5) Post-Installation Expectations Determining whether or not your installation was successful is best determined before you install the system. From the data you collected during the baseline procedure pick the metrics you want to see improved and by how much. Each of those numbers have a cost associated with them and by improving them the costs of operating the system goes down. The rate at how much the costs go down will be different for each facility and possibly even per each air handler within larger facilities that have many different kinds of occupied spaces (like hospitals).
With how much the initial price of new UVGI Coil Irradiation systems has dropped in the past decade most facilities that have even minimal cooling loads can benefit.