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  1. #27
    Join Date
    Jul 2006
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    Chattanooga, TN
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    VRF systems with ductless drop in ceiling cassettes, is the future. Am doing one with 40 tons of capacity. No metal duct work. Complete temperature control in each room, no silly vav boxes or no ceiling return air issues, and a complete self-contained fresh air- exhaust system design in it own equipment design. Return air is eliminate...so is the mechanical room for the most part.

  2. #28
    Join Date
    Oct 2014
    Location
    Columbus, Ohio
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    Quote Originally Posted by static regain View Post
    VRF systems with ductless drop in ceiling cassettes, is the future. Am doing one with 40 tons of capacity. No metal duct work. Complete temperature control in each room, no silly vav boxes or no ceiling return air issues, and a complete self-contained fresh air- exhaust system design in it own equipment design. Return air is eliminate...so is the mechanical room for the most part.
    The only problem with the fresh air intake on those is that they require FILTERED, CONDITIONED air - which means that you have to pipe in fresh air from a DOAS unit, and you can't just connect them to an outside wall intake.

  3. #29
    Join Date
    Feb 2004
    Location
    New Mexico
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    Quote Originally Posted by static regain View Post
    VRF systems with ductless drop in ceiling cassettes, is the future. Am doing one with 40 tons of capacity. No metal duct work. Complete temperature control in each room, no silly vav boxes or no ceiling return air issues, and a complete self-contained fresh air- exhaust system design in it own equipment design. Return air is eliminate...so is the mechanical room for the most part.
    Before you can suggest these systems are the future a couple snags need to be fixed. One is they are too expensive along with repair parts on a slow boat from China.
    #2 Where are the people that can fix these things. I'm not meaning the guys here on forum, I'm mean the guys out there. And certification requirements.
    Overly complex. Parts become their exclusive domain.
    I should have played the g'tar on the MTV. MK

    You can be anything you want......As long as you don't suck at it.

    SMW Lu49

  4. #30
    Join Date
    Jan 2015
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    Bellevue, Washington, United States
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    Most of the time you'll find that a mechanical room is built to be fire proof. That's to help contain a fire if something happens with the furnaces. Now if you use the mechanical room for return air the room won't be sealed off anymore. Instead the room will have a giant air return through the wall. That would raise problems with the fire safety of the entire building.

  5. Likes DavidDeBord liked this post
  6. #31
    Join Date
    Feb 2004
    Location
    New Mexico
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    The room is part of the return system. There will be grills in the wall or floor or where ever the return comes from.
    I think this idea has problems with acceptance is because it's against code for a return to be in the same room as any fuel burning equipment. As there is no fuel being used all there is are air handlers and maybe pumps, HW coils etc.
    Anything that could happen could happen if ducts were involved. I've seen returns simply dumped into mechanical rooms.
    I should have played the g'tar on the MTV. MK

    You can be anything you want......As long as you don't suck at it.

    SMW Lu49

  7. #32
    Join Date
    Mar 2015
    Location
    Hamersville, Ohio
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    The State of Ohio Code is concerned not only about Fuel burning Equipment, but also Air Movement at 2000 CFM. This set-up in the O.P., "If", it were allowed, would also involve Fire Dampers, as well as an approved Smoke/ Fire Detector mounted within the duct &/or Room, that is used for the "Return Plenum".

  8. #33
    Join Date
    Jul 2006
    Location
    Chattanooga, TN
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    26
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    Regardless of the system, all fresh air needs filtered, correct? Using a emc fresh air central fan system works go. We are getting ready to eliminate a Trane chiller system 60 ton with mini split! Energy saving alone are substantial saved each year..more control zone and the elimination of zone control boxes. When the system was designed 1982! It was 20 ton oversized. An equipment dealer must have N manual that one.

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