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  1. #14
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,646
    Quote Originally Posted by skippedover View Post
    Sure. With the wireless control, select 'dehumidify'. the indoor blower slows dramatically, just enough to keep the coil from freezing and the TD widens dramatically. Just like a regular humidifier. That's why it's manually selected and why they call it 'dehumidify' mode. Just like any other dehumidifier, there will be some slight cooling effect but it's normally minimal. Otherwise, if the air is already cool, we call that a heating situation. Raising the temperature of the room without adding moisture will lower the relative humidity. Them's the laws of physics at work.
    This is a nice idea that does not work. Here what will happen. The system starts as you discribe. Most basements are 68-70^F with +50%RH. The best a mini split can do is 70% sensible with 30% latent cooling. Cooling coils must collect 1 lb. of moisture per ton of coil capacity to wet the coil before moisture moves from the coil to condensate pan. 1 lb.of moisture removed from 900 sqft. of space lowers the moisture 10%RH. 1 lb. of moisture is 1050 btus of latent cooling which requires the a/c to provide 3-4,000 btus of sensible cooling. Assuming that the 1 lb. of moisture removal satisfies the dehumidistat, shutting of the a/c. The 1lb. of moisture on the coil/pan will re-evaporate back into the air in the cool space over the next 1-2 hours.
    In the case of over-cooling and shifting back to heating, the moistue will evaporate back into the space is 15 mins.
    It is interesting to monitor. The cooling/heating cycle will repeat and a small amount of moistue will be removed at great cost.
    Of course you know how a dehumidifier works. Moisture is removed and heat is returned to the space, which inturn lowers moisture and increases the temp which in turn reduces the amount of moisture that must be removed.
    Some major a/c manufactures attempted several this concept years ago.
    If you have this working some place, I would like to data log the processes. Cooling systems including dehumidifiers retain moisture on the cooling coil which will evaporate back into the space. The key is to remove enough moisture during the cycle to dramatically reduce the moisture in the air. Cooling/reheat cycle with over-cooling cycle is not long enough.
    If you want further disscusion, please post the issues.
    My main point was that giving advice about a concept that will not provide the intended effect should be avoided.
    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"

  2. #15
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
    Posts
    2,744
    Quote Originally Posted by teddy bear View Post
    This is a nice idea that does not work. Here what will happen. The system starts as you discribe. Most basements are 68-70^F with +50%RH. The best a mini split can do is 70% sensible with 30% latent cooling. Cooling coils must collect 1 lb. of moisture per ton of coil capacity to wet the coil before moisture moves from the coil to condensate pan. 1 lb.of moisture removed from 900 sqft. of space lowers the moisture 10%RH. 1 lb. of moisture is 1050 btus of latent cooling which requires the a/c to provide 3-4,000 btus of sensible cooling. Assuming that the 1 lb. of moisture removal satisfies the dehumidistat, shutting of the a/c. The 1lb. of moisture on the coil/pan will re-evaporate back into the air in the cool space over the next 1-2 hours.
    In the case of over-cooling and shifting back to heating, the moistue will evaporate back into the space is 15 mins.
    It is interesting to monitor. The cooling/heating cycle will repeat and a small amount of moistue will be removed at great cost.
    Of course you know how a dehumidifier works. Moisture is removed and heat is returned to the space, which inturn lowers moisture and increases the temp which in turn reduces the amount of moisture that must be removed.
    Some major a/c manufactures attempted several this concept years ago.
    If you have this working some place, I would like to data log the processes. Cooling systems including dehumidifiers retain moisture on the cooling coil which will evaporate back into the space. The key is to remove enough moisture during the cycle to dramatically reduce the moisture in the air. Cooling/reheat cycle with over-cooling cycle is not long enough.
    If you want further disscusion, please post the issues.
    My main point was that giving advice about a concept that will not provide the intended effect should be avoided.
    Regards TB
    That is really heavy, dude .........I'm truely impressed. One suggestion for your "Bear Rules" list.....have a professional check the ductwork for proper sizing.

  3. #16
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,803
    Zoning will help to reduce the amount of cold air your basement receives. Insulation the duct work if it isn't already will also help.

    Good chance your basement will need a dehumidifier, that will also help it from getting too cool in the summer.

    Using the radiant heat to try and warm up the first floor a bit, won't save any money.
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    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

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