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As most facilities, maintenance and service engineers know – “Going Green” without “breaking the bank” typically requires stepping-up maintenance practices on existing equipment and replacing old equipment only when it can no longer provide the efficiency needed even under the best of maintenance practices. But replacing old machines with new energy efficient equipment doesn’t guarantee you will realize the full efficiency benefit if your maintenance practices don’t prevent fouling of the condenser coils. Note: the term “prevent fouling” is used to distinguish it from the notion that traditional maintenance methods allow coils to go from clean to dirty or, said another way “go from efficient to inefficient” between cleanings vs. practices that protect the coils from fouling in the first place.
Energy Savings & Efficiency Not Happening Here
Dual Coil with fouled inner coil
Said a different way – if you don’t protect condenser coils on high efficiency systems, they will not deliver the promise of lower energy cost and optimal efficiency.
Rising energy costs combined with the basic need to optimize cooling and operational efficiency are key forces driving the changes we see in today’s process chiller designs. More and more companies are moving to both “green” preventative maintenance practices and energy efficient equipment that provide greater heat rejection capability at lower operating costs.
When adopting green maintenance practices, companies are realizing the importance of protecting their condenser coils and are widely using air intake filter technology commonly known as “Cottonwood Filter Screens”. When mounted over the condenser coils on older equipment, cottonwood filter screens keep the coils clean so the equipment operates at its designed efficiency level throughout the season. When mounted to high efficiency systems where coils are closer together and can trap smaller debris between them – Cottonwood Filter Screens stop the debris before it gets into the coils and can become a problem. Important Note: if high efficiency condenser coils are dirty, the equipment will not deliver the efficiency they are designed to deliver.
Filter Screens Stopping Airborne Debris
If you are thinking that you would be trading the cleaning of condenser coils for cleaning filter screens - you would be correct; however, the difference in the cleaning process is like night and day. When cleaning condenser coils, traditional methods call for the use of coil cleaning chemicals and pressure washers – This is typically a dirty, time consuming job which can be harmful to the coils and the environment; Conversely, using cottonwood filter screens will keep debris out of the coils in the first place and when the filters need cleaning, all that is needed is a broom, brush, shop vacuum or garden hose – even the rain can rinse them clean. Filter Screens do not require removal for cleaning and can reduce maintenance time and effort by up to 75%
A bio-medical facilities main air handling units had been experiencing on-going problems during the winter; snow would be drawn through the intake louver on one side of the building where it would accumulate on the MERV 8 pre-filters until the weight and moisture from the snow caused them to collapse; thus exposing the expensive MERV 15 bag filters which they relied upon to provide fine filtration to help in delivering optimal indoor air quality.
Snow Damaged Pre-Filters In Air Chamber
Because of this on-going winter problem, the maintenance team had to change 30 pre-filters every two weeks during the winter season (8 times) per winter and another four (4) times during the spring, summer and fall for a total of 12 times per year. Every time pre-filters were changed it would take 2.5 man hours and cost approximately $215 in filter & labor cost. Bag filters were changed two times per year and it would take 4 man hours for per change, costing $1,095 in filter & labor cost. In the section of the building where this unit is located there are no elevators, hence the overall cost includes the time needed to move the new filters up several flights of stairs from the dock, removing the old ones, installation of new ones and taking the old filters down to the dumpster. When changing the pre-filters it took two round trips up and down the stairs (24 filters per box) and when changing the bag filters it required 15 round trips up and down the stairs (3 large filters per box). During the winter, they had to constantly check on the filters because if the pre-filters got blinded-off with snow it would impact air flow – and if they collapsed between inspections the bag filters would become damaged and compromise indoor air quality. Because this air handling unit services critical laboratories, they simply could not allow the filtration system to be compromised – They needed a solution.
Approximate annual cost for managing this problem = $4,770 (excludes constant inspection time)
Solution
In 2006, the maintenance team became aware of Air Intake Filter Screen Technology - The filter screens are specifically engineered to have little impact on air flow and static pressure and stops airborne debris at its point of entry. Though this appeared to be the right solution, the filters needed to be mounted inside the air chamber behind the louver where it was accessible from inside the building rather than to mount them to the outside of the intake louvers which would limit accessibility as the outside of the louvers were located several stories up in the air and not accessible. The idea was to use the air intake filters to significantly reduce the amount of snow reaching the pre-filters and bag filters.
Since putting the filters in, they not only eliminated snow related damage, but they realized another benefit – The Air Intake Filters stopped cottonwood seed and other matter from pre-maturely fouling out our pre-filters during the spring, summer and fall. “It wasn’t until we saw the cottonwood seed building up on the Air Intake Filter Screens that we realized just how serious our cottonwood seed problem was. The cottonwood seed and other fibrous matter in the air was increasing our maintenance cost and significantly reducing the efficiency and service life of our filters” said the facility maintenance engineer.
Filter Screen Shown With Cottonseed
Since installing the Air Intake Filter Screens on their air handling unit, pre-filter changes have been reduced from twelve times per year to only three; and instead of changing bag filters twice annually, they now change them one time per year and anticipate that when nearby construction is completed that they will be able to reduce bag filter changes to one time every other year. Furthermore, reducing filter changes is consistent with the university’s campus-wide “Green Building” initiative – reducing the number of filter changes reduces filter waste and contributes to their aggregate waste reduction – less waste goes to land-fill. As a result of these impressive results, the university maintenance team is working with their filter screen representative to integrate the technology on other equipment across campus – “The cost savings opportunity is simply too great not to pursue this on a campus wide basis”, Said the Facilities Maintenance Engineer.
Cost Justification.
Because of the durable nature of the Air Intake Filter Screens, they will provide 15+ years of service. Therefore, when weighing the cost of annual maintenance on the air handling unit without the Air Intake Filters vs. with them, the annualized cost of managing the system with the Air Intake Filter Screens yields a significant annual savings and a 2.9 year investment payback.
Old Method Cost (without Air Intake Filter Screens)
1. Annual Maintenance including pre-filters, bag filters & labor = $4,770
New Method Cost (with Air Intake Filter Screens)
1. Total Cost for Air Intake Filter Screens, Frames and Installation = $7,885
2. Annualized Cost of Using Filter Screens ($7,885 / 15 year service life) = $525
3. Total Annual Cost for pre-filters & labor (3 changes per year) = $645
4. Total Annual Cost for bag filters & labor (1 change per year) = $1,095
Air Solution Company today announced the introduction of its enhanced condenser coil Wind Guard System which is designed to help prevent compressor stalling during low ambient operation by preventing frigid air movement through the prevailing wind side of condenser coils.
“Although it seems counter intuitive to prevent airflow through a condenser coil, it is important to note that frigid ambient temperatures offset the air flow in rejecting heat. It takes as little as a 5 mph breeze blowing through condenser coils during frigid temperatures to dissipate the minimum heat required by the compressor for start-up; When this happens, process chillers can stall – leaving production equipment and operations starved for cooling until the compressors can be started” said Randy Simmons, VP & GM.
Traditional methods of preventing frigid air from directly passing through the coil include building a brick wind barrier around the chiller, attaching cardboard, plastic and plywood over the coil – Some OEM’s offer expensive, low ambient kits that assist in low ambient start-up.
Constructed of a heavy duty, fiber reinforced vinyl with a reinforced perimeter, grommets and quick release fasteners; the Wind Guard provides a cost effective and tailored solution to the problem. The fasteners which are included are also compatible with the companies patented Cottonwood Filter Screens which are designed to prevent airborne debris from fouling condenser coils, cooling towers, air handling units and other HVAC systems during Spring, Summer & Fall operation. Wind Guards are also effective at preventing snow and ice damage to cooling tower sumps and fill during winter shut-down.
For more information about Wind Guards and minimum chiller requirements for use of this product, contact Air Solution Company at 513-860-9784.
Rising energy costs combined with the basic need to optimize cooling and operational efficiency are key forces driving the changes we see in today’s process chiller designs. More and more companies are moving to both “green” preventative maintenance practices and energy efficient equipment that provide greater heat rejection capability at lower operating costs.
When adopting green maintenance practices, more and more companies are realizing the importance of protecting their condenser coils from fouling and are using air intake filters commonly known as “Cottonwood Filter Screens”.
When mounted over the condenser coils on older, less efficient equipment, it helps to optimize the efficiency level of the equipment by keeping the coils clean so the equipment can operate within an acceptable efficiency range – and in many cases, this is a significantly more cost efficient approach vs. replacing the equipment with “high efficiency” equipment. As most facilities and maintenance engineers know – “Going Green” without “breaking the bank” typically requires stepping-up maintenance practices on existing equipment and replacing old equipment only when it can no longer provide the efficiency needed even under the best of maintenance practices.
But replacing old equipment with new energy efficient equipment doesn’t guarantee you will realize the full efficiency benefit if your maintenance practices don’t prevent fouling of the condenser coils.
Cottonwood Filter Screen Protecting 400 Ton Chiller
To provide higher efficiency, many OEM’s have concentrated on refrigerants and condenser coil technologies to achieve heat rejection efficiency never seen before. High efficiency coils with “micro fins” increase the density of coil fins while expanding the heat rejection surface area to enable rapid heat rejection – but if the coils aren’t protected from airborne matter (insects, cottonwood seed, pollen, leaves, etc), then these systems tend to foul faster then non-micro fin systems as a function of the fins being closer together and trapping more debris between them. When this occurs, the high efficiency equipment will not deliver the efficiency and lower operating cost benefit.
Rain Rinsing Filter Screens Clean
Important Point: “Air cooled condensers and chillers will operate at an increasing level of inefficiency between coil cleanings if coils are unprotected”. Then, when coil cleaning occurs it is usually an unpleasant, time consuming job requiring the chiller to be taken “off-line” for up to 1.5 days, depending upon the size and architecture of the equipment. However, when coils are protected with Cottonwood Filter Screens – It prevents coil fouling and reduces the cleaning process to a fraction of the time required using traditional cleaning methods (coil cleaning chemicals and power washers).
Cottonwood Filters Screens are not made of an ordinary mesh – rather, they are specifically engineered for use in high volume, high velocity air movement systems with extraordinary low impact on static pressure; further, the “non-stick” mesh surface enables cleaning with a broom, brush, shop vacuum or garden hose – even the rain will rinse them clean – and best of all they never need to be removed for cleaning.
In short, Cottonwood Filter Screens can change the dynamics of your maintenance process and enable your equipment to operate at optimal efficiency level, while significantly reducing your maintenance time & effort and operating cost; and for companies seeking LEED certification, Cottonwood Filter Screens can help you earn LEED credit points in multiple categories.
With the winter heating season closing in on us, facilities engineers are getting buildings buttoned down and heating equipment ready for winter. Although the cool weather marks the end of the environmental “comfort cooling” season, it doesn’t end for “process cooling”.
Since process manufacturing requires year around cooling, manufacturers commonly perform a final cleaning during the third or early fourth quarter because once the winter weather hits, cleaning cooling equipment becomes prohibitive – especially in the upper half of the US and in Canada.
As you enter the year end maintenance cycle, reflect back on the challenges of this season and ask yourself – what important HVAC maintenance activities took too much time and energy but were necessary for process and system optimization? Then ask yourself what can be done during the last maintenance cycle to make life a little easier next spring and summer.
Undoubtedly, one of the most time consuming and unpleasant tasks is cleaning condenser coils and cooling towers;
Traditional Coil Cleaning Method Using Power Washers & Cleaning Chemicals
It requires getting water, power washing equipment and cleaning chemicals to each mechanical unit plus, proper cleaning can take as little as an hour to as much as a day or more depending upon the size of the cooling system. In some states, the cleaning process is further complicated by state and local laws that require reclaiming and proper disposal of the cleaning solutions (including biodegradable chemicals) so they don’t harm the environment.
Cooling Tower & Chiller Filter Screens
If cleaning condenser coils and cooling towers fall near the top of your “Hate to Do” list, then Cottonwood Filter Screens could be just the solution you are looking for.
Cottonwood Filter Screens mounted over the intake opening stops airborne debris at its point of entry so you don’t have to manage the debris after it gets into your system; Furthermore, it streamlines maintenance to a few quick swipes of a broom, brush or shop vacuum, or simply rinse with a garden hose – even the rain will rinse them c lean – and best of all, the cottonwood filter screens will provide up to 15 yrs of service and they don’t require removal for cleaning. When compared to traditional cleaning methods, it just doesn’t get any easier than this!
Unlike, screening materials that you can buy at hardware or canvas shop and that can damage your mechanical equipment; Cottonwood Filter Screens are specifically engineered for use on all makes and models of cooling equipment and will not void equipment warranties.
So, if you are looking for a way to reduce energy cost, earn LEED credits while significantly reducing maintenance time and effort, then cottonwood filter screens is a year end maintenance enhancement to consider, as they will reduce next spring and summers maintenance challenges.
Your Comments Please: What do you do to prepare for spring during the winter maintenance cycle?
When in-house HVAC maintenance jobs are lost, the workload doesn’t usually change, it just falls on fewer shoulders – and despite creative measures to manage the work load, all too often maintenance is reduced or deferred because recommend maintenance intervals simply cannot be properly met. This situation usually means that HVAC maintenance engineers must find creative ways to manage the workload and/ or invest in preventative maintenance technologies that enable a smaller workforce to manage what a larger work force once managed. Use of cottonwood filter screens is a good example of an effective way of reducing the maintenance time and effort to a fraction of that required using traditional power washers and cleaning chemicals because they stop debris on the outside of the equipment where it is easy to clean vs. having to manage the debris after it has entered and fouled the system.
Please comment on the following questions:
When faced with lean staffing, what creative steps do you (or if a distributor, your customer) take to keep up with the demands of HVAC maintenance?
How do you (or your customer) prioritize what equipment gets worked on?
What impact has reducing or deferring maintenance had on mechanical equipment efficiency, repair costs and energy usage?
If the equipment across the operation supports production processes, what impact has reduced or deferred maintenance had on production quality and efficiency?
If you (or your customer) already use cottonwood filter screens, how has it changed the dynamics of the maintenance process?
Dual Coil with fouled inner coil
Cooling Tower & Chiller Filter Screens
