The most common question asked by both representatives and engineers is, “When should I order a custom air handler?”

 

The simple answer is “always!”

 

The more practical and realistic answer is a little more complicated – but not much.  There are several aspects to be taken into account but none are difficult.  Here is a short list of items to look for that will take a standard specification to custom:

 

• Wall thickness of more than 2”
• Air leakage of less than 1% of design CFM for unit
• Static pressure beyond the typical commercial standard of 6” – 8” wc
• Unique construction materials
• No-thru casing construction (not to be confused with thermal break)
• Units requiring single point and/or special electrical power connection
• Factory controls systems – either OEM or special vendor such as Allen Bradley
• Factory piping systems – including steam, chilled water, hot water, DX, etc.
• Units requiring integrated cooling packages including air or evaporative condensers, chillers, etc.
• Penthouse systems
• Units with vestibules or service corridors
• Stringent sound criteria or ultra low noise units
• Units with unusual geometry – round, L-shaped, multi-story, manufactured to be assembled around existing support columns, etc.
• Direct fit replacement units that are being mated to existing ductwork and/or curbs
• Desiccant dehumidification units
• Units using any form of energy recovery

 

Each of these features by itself could push a standard or semi-custom unit entirely into the realm of TRUCustom®.  However, where we find the greatest opportunities to exist are where an owner/contractor/engineer combines several of these features into the specification and holds the specification to prevent “value engineering” bidding.

 

Let’s touch on a couple of the “high profile” attributes:  leakage and energy recovery.

 

Air leakage is by far the biggest cause of air handler inefficiency.  The tighter the casing the better the unit is able to move the conditioned air to where it belongs.  Air losses through cabinet leakage are a direct loss of energy dollars and can significantly contribute to the heating and cooling costs of a given space.  We have a great example of this on our website.  Please visit us at www.marcrafthvac.com and check out the Custom HVAC tab then click on Cost Savings/Payback.

 

The other area that is very much on everyone’s mind is energy recovery.  How can we maximize our heating and cooling dollars by recovering as much as possible of the energy put into the system?  There are many ways to accomplish this – energy recovery wheels, air-to-air heat exchangers, heat pipes and run around loops are the common sources.  Each fulfills a certain niche and has an associated percentage of efficiency (see our website for more detail).  It is part of the expertise of the TRUCustom® manufacturer to assist you in this choice and provide optimal performance of the unit.  Always keep leakage in mind when thinking about your energy recovery system.

 

In each of these examples we can see that knowing even a little about what makes an air handler “custom” can create new opportunities.  What is most important is being able to effectively communicate what constitutes custom to your audience, whether owner, contractor or engineer.  It will move you into the role of educator/consultant.

 

FOR IMMEDIATE RELEASE
March 15, 2011

CONTACT: Steve Miller  This e-mail address is being protected from spambots. You need JavaScript enabled to view it
314.739‐0037
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Arizon Companies Acquires Vital Air Technologies
With its Award Winning DryMAX™ Product, the world’s first and only mini-split TRUE Dehumidification Unit.
St. Louis MO—Arizon® Companies, parent company of Johnson Air Rotation® Systems, MARCRAFT® Custom HVAC Systems, and Arizon Structures, is proud to announce its most recent acquisition, Vital Air Technologies, a leading manufacturer of commercial and industrial grade dehumidification products. “Adding the DryMAX™ and Aqua-TEC™ dehumidification products to the Arizon Companies product mix offers several key benefits for our clients,” says Doug Howery, Vice President of Arizon Companies, who handled the acquisition. Howery also states, “As with other Arizon Company products, we are revitalizing and expanding the Vital Air Technology products to lead their respective niche markets with innovation and project solutions.”
Vital Air Technologies was previously a division of Thayer Corporation, a contractor and manufacturer of a complete range of heating, ventilation, air conditioning, plumbing and refrigeration solutions for both commercial and residential applications. “We are glad to see Vital Air Technologies and its products continue on with a passionate company who will grow them into what we know they can become,” says Dan Thayer, founder of Thayer Corporation.
Vital Air Technologies’ DryMAX system, the world’s first and only split system or “mini-split” to incorporate a true dehumidification cycle with a dual coil, is now available exclusively from Arizon Companies. DryMAX Systems are used in new and retrofit applications for humidity control in demanding situations. The 2.5 ton system can remove up to 14 lbs. of water per hour, ideal for indoor swim spas, smaller hydrotherapy pools and hot tubs. Units may also be used to provide control in larger residential and hotel/motel pools where installation of a traditional unit would not be possible or cost effective. DryMAX recently was awarded the AHR Expo Innovation Award, an Honorable Mention for IAQ products, as well as the Silver Award in the Indoor Air Quality category by the NEWS Dealer Design Awards.
For more information on Arizon Companies, please check us out on the web at www.arizoncompanies.com. Also, don’t miss Johnson, MarCraft, and Arizon Air Structures on Facebook and “Like Us” today.

About Arizon Companies
Arizon® Companies manufactures and installs industry-leading product lines: Johnson Air Rotation® and Make-Up Air Systems, MarCraft® Custom HVAC Systems, Arizon® Air Structures, Frame Fabric Structures and Tension Structures and Vital Air Technologies Dehumidification Systems. To learn more about Arizon Companies—or any of its product lines—visit www.arizoncompanies.com or call Steve Miller in our St. Louis, Mo., office at (800) 325-1303.

When designing an air handling unit with energy recovery, many people shy away from Energy Recovery Wheels because of the concern of cross contamination between airstreams.  Many people overlook the fact that when a recovery wheel is applied properly with purge, cross contamination is less than 1%.   More importantly casing leakage around the energy recovery device can be key to any Energy Recovery Unit where cross contamination is a concern.  With commercial units leaking as much as 10%, semi custom leaking 3% to 5%, one must look at a unit housing that prevents this sort of excessive leakage. 

The need to prevent casing leakage is not only for cross contamination but also for energy efficiency.  Assume your designing or buying an Energy Recovery Unit which leaks 5% of its design airflow at operating pressure.  You should then derate the units energy savings by the leakage of air from it.  A TRUCustom Unit similar to MarCraft's ZERO CASING can provide less than 1/4 of 1% leakage performance up to 18" w.c.  This means for every $1 you spend on your Energy Recovery Unit, you keep $0.9975, paying you back in the recovered Energy for years to come vs. other typical systems which may have 5% leakage and you keep $0.95.  That is a nearly a $.05 savings for every dollar spent in operational cost for the life of the equipment, plus the added peace of mind of nearly 5% leakage and potential cross contamination of the system.

UV Emitters – Add Life to your Cooling Coils

and Efficiency to your System

 

A cooling coil in an air conditioning system is designed to cool the air passing across it. While operating, dehumidification occurs, dropping moisture out of the air and onto the outer surfaces of the coil and into the drain pan. The coil can remain moist for extended periods of time creating a perfect environment for breeding bacteria, molds, mildew, and calcification deposits. These contaminants not only cause a health hazard, they also cover the surfaces of the coil, decreasing operating efficiency.  Installing UVC emitters can help keep the coil clean by killing the organic contamination and breaking down calcification and mineral deposits.

 

When placed on the downstream side of the cooling coil and above the drain pan, constant cleaning and decontamination is realized. Killing the bacterial growth on the coil will maintain the coil’s heat transfer efficiency, extend the life of the coil and lower the air pressure drop thus reducing operating costs. Installing UVC lights on your cooling coils can give you the piece of mind knowing your air conditioning system is free from harmful and unhealthy contaminants while running efficiently saving the owner operational costs and maintenance month after month. UVC lighting is also effective as a retrofit to older systems and will restore the performance by breaking down growth and minerals on the coils surface.  Payback can be realized in as little as 1-2 years.  Keep the unit GREEN and the owner keeps his GREEN in his pocket…why wait contact MarCraft today! 

Did you know that over 90% of the energy wasted in a 2” Foam Wall Modular Air Handler is due to Casing Leakage?  Modular air handler manufacturers made a big push stating that foam insulation will help reduce thermal losses through the unit casing, therefore will reduce the energy wasted in the air handler.  However, they neglected to address the casing leakage issue.

Modular Air Handlers leak 5% of design airflow at 5” w.c. of total static pressure.  That means that the modular unit needs to be oversized by at least 5% in order to properly condition the space it is serving during the lifetime of the unit.  Air handling units as manufactured by MarCraft TruCustom HVAC Systems leak less than 1% of design airflow at 10” w.c. of total static pressure.  With MarCraft’s ultra-low leakage option, Zero Casing®, average casing leakage rates are less than ¼ of 1% of design airflow at 18” w.c. of total static pressure.  On a 25,000 CFM unit being installed in St. Louis, MO, the cost of wasted energy due to casing leakage for a modular air handler is at least $5,000/year more than on a MarCraft TruCustom unit and at least $6,000/year more than on a MarCraft Zero Casing® unit.  Keep in mind that does not include the added costs for oversized chillers, boilers, etc.

MarCraft Provided The Heating And Cooling Solution For The Crystal Bridges Museum Of American Art.  A Story On The Crystal Bridges Museum Was Featured In The July 4th Issue Of Engineering News-Record.  Read the Story at 

http://enr.construction.com/buildings/construction_methods/2011/0704-ArtfulBalancing.asp

TruCustom vs. Custom

 

Some of the differences between a MarCraft TruCustom HVAC System vs. a “Custom” Air Handling Unit are:

 

• 4” or Greater Wall Thickness – Great for High or Low Temperature Units
• Typical Casing Leakage  rates of 1 / 2 %   of Design CFM at 12” w.c. of Total Static Pressure  with optional rating at 1/4% of design CFM with our ZERO CASING housing.  
• ZERO CASING & ZERO+ CASING Ultra low leak systems provide much better efficiency while reducing cross contamination.  Key for Energy Recovery Systems and Lab/Clean Room Systems.  
• Special Materials of Construction – Units manufactured entirely out of aluminum can save 30-40% on weight, Saving money on structural costs on the job sites
• TRU No-Thru Metal Casing – Reduces the thermal energy losses radiated through casing.  Another great feature for high or low temp units.   
• Full Electrical and Controls Systems from a variety of manufacturers to match existing campus standards.  Custom programming and integrations packages available. 
• Full Piping Systems DX, Chilled Water, Hot Water, Steam as well as Air and other fluids – Reduce Installation Time of Custom System while reducing jobsite costs and increasing quality. 
• Fully Custom Aspect Ratio – Typically units are designed for the maximum interior airflow speed to be approximately 500 FPM for the filters and cooling coils.  Therefore, a 20,000 CFM air handling unit requires a minimum of 40 sq.ft. of interior casing area.  Thus, 4 ft. high by 10 ft. wide and 4 ft. wide by 10 ft. high both meet the minimum requirements for the air velocity.  However, in one instance the air handling unit may be installed in a room that is only 8 ft. wide but is tall enough to fit an air handling unit with an interior height of 10 ft.  In another instance, the air handler may need to be designed to go through a 7 ft. high door, in which case the 4 ft. interior height is more appealing.
• Unusual Geometry – Assume an air handler may require 30 ft. of length to contain all components; however, the mechanical room where the air handler is going is only 25 ft. wide by 25 ft. long.  MarCraft can provide an “L”-shaped air handling unit to include all of the different components and still fit into the space provided.   Want a round unit, what diameter?  Want it stacked, how high?  Need to fit an elevator and split in all 3 planes, what are the requirements?  Field assembly is always less costly than field built, TRUCustom can help you achieve this. 
• Replacement Units Including Direct Fit of Existing Curbs and Ductwork – This will reduce installation costs during a retrofit project.  
• Fully packaged Mechanical Equipment Rooms, Chiller Plants, Boiler Plants and/or TRUCustom Penthouse units are great options to meet tight schedules, tight spaces, and tight budgets!

 

Contact MarCraft today to learn more about TruCustom HVAC Systems.