Chillers vs AC

Discussion in 'New to Reefing' started by Jojo1628, Jun 25, 2008.

  1. Jojo1628

    Jojo1628

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    I'm thinking of investing in chillers, but I want to be cost effective in the long run...would it be cheaper to run an 10k btu AC to cool a room like 400 sq feet or cheaper to get a chiller to run that alone? Btw, it's a split AC unit, so a bit more efficient than the conventional AC...
     
    Jojo1628, Jun 25, 2008
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  2. Jojo1628

    Rcpilot

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    A split system is when you have the big compressor unit with all the coils outside and the smaller coil (radiator) is inside the house inside the furnace. The furnace (air handler) blows air across the cold coil and that makes the air cooler. Typical temp drop should be 18--20 F across the coil.

    The other type is what we call a "window banger". You get the idea. :mrgreen:

    I'd run a Sanyo or Mitsubishi "mini-split" in my tank room. A mini-split is usually smaller than the conventional house air conditioner that most people refer too as "central air conditioning". Central air conditioning is a split system. A mini-split is just a smaller version of that.

    Mini-split systems come in sizes from 1 ton of cooling up to about 3 tons of cooling. For comparison, the average house about 2000sq.ft takes a 5 ton split system +/-. A "ton" of cooling is equal to 12,000 BTU. So, 5 tons is 60,000 BTU. 10 tons is 120,000 BTU.

    A mini split is more efficient to operate than a window banger. Also cheaper to operate than your house central air system.

    If all you want to do is cool a room 400sq. ft., you'd need about 1 ton or 1.5 tons of cooling at the MOST. Keep in mind I'm using generalizations here. The only way to REALLY know how much cooling you need is to do a "load calculation" and we ain't doing that on Living Reefs. I ain't goin' near a load calc. in a reefing forum. :frustrat: :mrgreen:

    A little bit bigger is better--but no too big. You want it to be able to cool the room without running 24/7. Figure about 30%---50% duty cycle. But if it's too big, it will "short cycle" all the time. Short cycling is when the unit is so big that it will flash cool the room in just 2 or 3 minutes. That shuts the thermostat off. But the unit didn't REALLY circulate all the hot air in the room, so you still have humidity and hot air in the room. If the air doesn't go across the cold coil, it can't get rid of the excess humidity or the heat. The thermostat trips again and turns the unit on. Instant cold air. FREEZING cold air in a room thats too small. Thermostat shuts off again. Hot spots circulate around--thermostat turns on again. Freezing cold air floods the tiny room. Thermostat shuts off again. Vicious circle.

    A chiller is cheaper, but the mini-split is more energy efficient to run. The mini-split also doesn't need to be plumbed into the tank. Less risk of a flood or malfunction that will kill the tank. If the chiller fails--your up a creek. If the mini-split fails, the tank may get hot, but you don;t have to drain it to fix it. The 1 ton mini-split will probably run you $2000--$2500 from the local HVAC contractor.
     
    Last edited: Jun 25, 2008
    Rcpilot, Jun 25, 2008
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  3. Jojo1628

    ZOOT098

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    rc........
    i think he just wants a window air conditioner
     
    ZOOT098, Jun 25, 2008
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  4. Jojo1628

    Rcpilot

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    No.

    He asked if it was worth it to buy a chiller or run a split system. He said it is a split system, so more efficient than a window unit.

    I'd do a mini-split, but I can get it at cost and put it in myself for about $1000.
     
    Rcpilot, Jun 25, 2008
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  5. Jojo1628

    yote Ceritfied Mantis Hunter Moderator

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    I gotta agree with Rc.I'd go with a 2 ton mini-split over the chiller or the window unit.
    The reason being.When that chiller kicks on,the compressor gets hot,then the fan blows that hot air out into the room.That causes more heat so the chillers got to work more to keep the tank cool.
    Plus the mini-split is a lot more efficient than the window cooler.
    I think that in a 400sqft room,that 2 ton would be plenty.
     
    yote, Jun 25, 2008
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  6. Jojo1628

    Rcpilot

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    I'd do 1.5 tons MAX. Thats a helluva lot of cooling on 400sq ft. Typical residential AC is sized at 400--600sq. ft. per ton. I think 2 tons would probably cause it to short cycle as I described in my other post. Depends on the heat load though--and the humidity is going to be high. On second thought 2 tons might be about right.

    Never mind. :mrgreen:
     
    Rcpilot, Jun 26, 2008
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  7. Jojo1628

    Jojo1628

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    wow...thanks RC for the technical report...my mind's spinning reading that...lol but yea my room already has a split AC unit...i don't think it's a mini split, so I'll prob skip a chiller due to the hot air exhaust, prob cost more to run a chiller than to keep all my curtains closed and keep the split ac on set temp.
     
    Jojo1628, Jun 26, 2008
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  8. Jojo1628

    cgoodman381 can i put whtever i want?

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    Rc you lost me at a split system.... Computers are my thing :p
     
    cgoodman381, Jun 26, 2008
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  9. Jojo1628

    Rcpilot

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    Whats a computer? :shock:
     
    Rcpilot, Jun 26, 2008
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  10. Jojo1628

    Bifferwine I am a girl

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    Yote is right, chillers will create heat outside of the tank, so they aren't practical unless you have a way to vent that heat and/or cool the room at the same time. If you have a chiller on your tank but no AC in your room, your room temperature will get hotter from the exhaust from the chiller, which will make the chiller work overtime to keep the tank's temp down.
     
    Bifferwine, Jun 26, 2008
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