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  1. #1
    Join Date
    Apr 2005
    Posts
    62

    Wine cellar system with too much humidity, HELP!

    Problem: humidity levels reach above 70-75% in areas of the room...shooting for 60%....70-75 can cause mold.

    Reason: the air handler is too big for the 270 sq ft./2430 cu. ft. room with R27...etc. Or at least that is the theory...

    Using R410a I believe. I think the EPR is all the way out. The coil temp was brought down as close as they could to freezing...I think it was like 34, and there was some accounting for the very long lineset.

    System: MagicAire DVA10 air handler with a Copland 1.25ton BTAH-A125. Line set is ~85 feet long with 8-9 90s...yes you read that right. Return ducting is short ~1', supply is ~30 feet of ducting, 4 runs...16" into 2 x 12" into 4 x 8"...All galvanized...all insulated with the bubble wrap stuff with spacers...We've spent a lot of time sealing the system from the adjacent utility room, where the air handler sits. Room has closed cell foam insulation...air tight doors, etc..very little if any air infiltration...the ducting was sealed several times..

    Suggestion was to limit the airflow...As a test, I closed the dampers on the supply vents about 50% (they are 4 of 4x18s) and it does maintain humidity a little better...but it gets loud. Idea was to put the dampers in the 12" pipes and use those to limit the airflow. I am worried about adding pressure to the air handler, however..

    Also, I think the duty cycle is pretty low...no where near the 80% they want.

    Temp. is maintaining well, at 50 degrees. liquid variance is just .4 degrees...air variance is about 2 degrees or less. I set the control system to turn the unit on with a 2 degree limit - set at 49, it turns on at 51.

    Note the humidity is some areas of the room is closer to 60-65...Oddly...the room varies quite a bit, with the area by the door is heavily impacted by the door opening...As you can imagine, it is 100 today...lots of water in that air.

    1. Is this the correct approach to control humidity?
    2. Can you ruin the MagicAire air handler by limiting the airflow too much? I'm afraid of adding pressure...backflow pressure...to the system.
    3. Can you think of another solution? I thought about routing air to another room that gets hot -- a computer room.

    Thanks, -mark

  2. #2
    Join Date
    Apr 2002
    Location
    most of the time in the Philippines
    Posts
    1,211
    If you have excess cooling capacity, why not turn it into a reheat system with some strip heaters? It won't be cheap.

  3. #3
    Join Date
    Apr 2005
    Posts
    62
    Can you say more about the benefits of a re-heat system?

  4. #4
    Join Date
    May 2009
    Location
    Canada
    Posts
    38
    is it possible to lower fan speed on the air handler?
    lower speed = longer run time = more humidty removed.

    cooling the room to quick will not allow moisture to be removed.

  5. #5
    Join Date
    Apr 2005
    Posts
    62
    Nate- Good suggestion. We already moved the speeds from low/high to very low / medium. And we are adding dampers to limit the airflow -- I'm limiting the change to .5 ESP...Concern is that we need to move from a 1000CFM (DVA10) to 800CFM max. unit. (DVA08). Actually, at low speed and .5 ESP, it's 860 vs. 600 CFMs...

  6. #6
    Join Date
    Mar 2009
    Location
    Spokane WA
    Posts
    302
    mdavis, I am in a completely different climat than you but see this in other applications. I was at one of our wineries today and the outdoor humidity is about 10% and about 105 deg F. We humidify all summer long to prevent too much evaporation and product loss. That changes the alcohol also so it is not a good plan.

    Anyway, you need to probably suggest adding more cooling an re-heat like jhd1234 said. You have to strip that humidity from the air and reduce the airflow to pull more water from the air.

    If you have ever worked on a Liebert, they have larger evaps to limit moisture removal, moisture needs to stay in computer rooms a little more like a winery but you are getting too much influence from your outdoor which is saturated with moisture. With a Liebert you continue to run the DX and if it is getting too chilly then the re-heat comes on...

    I would also look at the envelope of the building. Is there a good vapor barrier? If the building is not tight you could use a million KW's trying to remove moisture and you are not going to make any headway!!

    Mother nature always wins.

    Good luck,

    JJ

  7. #7
    Join Date
    Apr 2005
    Posts
    62
    Thanks for the reply. I had closed cell foam blown in, with a really good PERM rating...the walls are tight and the foam acts like a 6mm visqueen vapor barrier.

    The whole heater thing is possible, but likely difficult for the company I am working with...I don't think the wine companies know how to do that here in Portland, OR...perhaps in the Midwest. I know MagicAire has something that will work however.

  8. #8
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,339
    Raising the temperature of the space upto 60^F allows using dehumidifiers like the Santa Fe/Ultra-Aire to maintain 50%RH. If <50^F is critical, I suggest looking at the dissicant dehus from Therma-Stor. All of the above are lower operating cost than reheat. Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  9. #9
    Not sure how well this would work.

    But would be easy to set up.

    Buy a room a/c (window wall).Approx 2hp. Install in refrigerated space.Remove thermostat and replace with humidistat, connect drain and run outside room. Would make no real difference to room temp as condenser and evap air are both discharged to room. Maybe room temp might rise slightly(heat of compression).might ice up after a while.

    Just an idea.........
    Last edited by temprite; 07-29-2009 at 08:27 AM. Reason: extra text

  10. #10
    Join Date
    Apr 2005
    Posts
    62
    Thanks for the ideas guys.

    Talked to a bunch of folks representing the wine HVAC company I am working with.

    They will install dampers to lower the airflow. I explained by concern that if we move beyond .5 ESP, we *could* cause issues with the longevity of the motor...or so said MagicAire the air handler company representing the DVA10.

    -mark

  11. #11
    Join Date
    Nov 2001
    Location
    Seattle, WA
    Posts
    7,756
    Quote Originally Posted by mdavis View Post
    Problem: humidity levels reach above 70-75% in areas of the
    You state that "areas of the room reach 70-75%" --- this doesn't make any sense as that small of a rooms should pretty much level out the humidity unles you have humidity entering in those areas.

    Also, 50 degrees is just to cold for a wine cellar or wine cooler. More like 55 degrees is best.

    You system is just too big and there is no real way to solve the problems without first finding out why certain areas of the room have a higher humidity then other areas.

    And the system capacity must be reduced once the walls, ceiling, floors and doors are sealed against humidity and heat infiltration.

    Then gut the existing system and install the evap inside of the room.
    "The American Republic will endure until the day Congress discovers it can bribe the public with the public's own money.
    - Alexis de Toqueville, 1835

  12. #12
    Join Date
    Sep 2002
    Posts
    12,248

    Throw an electric space heater in there

    Hold the evap coil temp as low as you can with the EPR. 33 degrees is nice.

    Lower your fan speed as much as you can.

    Then add a 1500 watt electric heater,

    Or; a large dehumidifier.

    PHM
    --------


    Quote Originally Posted by mdavis View Post
    Problem: humidity levels reach above 70-75% in areas of the room...shooting for 60%....70-75 can cause mold.

    Reason: the air handler is too big for the 270 sq ft./2430 cu. ft. room with R27...etc. Or at least that is the theory...

    Using R410a I believe. I think the EPR is all the way out. The coil temp was brought down as close as they could to freezing...I think it was like 34, and there was some accounting for the very long lineset.

    System: MagicAire DVA10 air handler with a Copland 1.25ton BTAH-A125. Line set is ~85 feet long with 8-9 90s...yes you read that right. Return ducting is short ~1', supply is ~30 feet of ducting, 4 runs...16" into 2 x 12" into 4 x 8"...All galvanized...all insulated with the bubble wrap stuff with spacers...We've spent a lot of time sealing the system from the adjacent utility room, where the air handler sits. Room has closed cell foam insulation...air tight doors, etc..very little if any air infiltration...the ducting was sealed several times..

    Suggestion was to limit the airflow...As a test, I closed the dampers on the supply vents about 50% (they are 4 of 4x18s) and it does maintain humidity a little better...but it gets loud. Idea was to put the dampers in the 12" pipes and use those to limit the airflow. I am worried about adding pressure to the air handler, however..

    Also, I think the duty cycle is pretty low...no where near the 80% they want.

    Temp. is maintaining well, at 50 degrees. liquid variance is just .4 degrees...air variance is about 2 degrees or less. I set the control system to turn the unit on with a 2 degree limit - set at 49, it turns on at 51.

    Note the humidity is some areas of the room is closer to 60-65...Oddly...the room varies quite a bit, with the area by the door is heavily impacted by the door opening...As you can imagine, it is 100 today...lots of water in that air.

    1. Is this the correct approach to control humidity?
    2. Can you ruin the MagicAire air handler by limiting the airflow too much? I'm afraid of adding pressure...backflow pressure...to the system.
    3. Can you think of another solution? I thought about routing air to another room that gets hot -- a computer room.

    Thanks, -mark
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  13. #13
    Join Date
    Apr 2005
    Posts
    62
    50 is the new 55..there is some evidence that 50 degrees is more optimal for wine storage.

    Humidity does vary 5-6% around the room...

    The coil is running around 40 degrees...

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