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  1. #1
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    Jul 2002
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    Ice Bank Efficiency

    Are there any published reports on the cost of chiller usage vs ice bank. Customer is debating if it's cheaper to run chiller or ice.
    Second place is the first loser.

  2. #2
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    Aug 2006
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    Mixing oil and fire with a big spoon.
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    generally speaking, ice is cheaper on energy usage but has a slightly higher first cost (even after the utility chips in) and takes up more room. to do a really good job, you will need an engineer to analyze the load profile of the building to determine the type of ice system and then you can move forward with the utility, etc.
    "Mother" is the name for God on the lips and hearts of children....The Crow

  3. #3
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    Sep 2008
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    Mesquite Tx.
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    It takes more kw to make ice than it does to make chilled water. The key is what your kw cost is and at what times. If you make ice when your power is a lot cheaper, then melt it to cool when power is more expensive, you can save $$$.
    Nos operor non pensio volutabrum

  4. #4
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    Quote Originally Posted by incontrol View Post
    Are there any published reports on the cost of chiller usage vs ice bank. Customer is debating if it's cheaper to run chiller or ice.
    Cheap is all relative to cost and source of energy. The ratio of energy removed per energy used by the machine is called coefficient of performance. One truth is that the greater the difference between the condensing and evaporating temperature, the more energy is needed to move the same amount of energy. The biggest influences are cost of needed utility and the mother nature.

    Cost is different. It's the amount of effect per dollar. Chillers use a combination of electricity and water to produce cooling effect. The cooling tower is a giant humidifier that humidifies the outdoor environment, so the utility bill and treatment chemicals for that water is part of the bill.

    Solid ice has the most storage density, but it's difficult to utilize it as you can't pump it around. Slush can be pumped around, but keeping it in constant circulation takes energy and storage density is lower, so you need more storage space.
    2,000 ton of ice, or about cubic metre.

    A solid block of ice that is 1 meter on each side will absorb 288,000 BTU to completely melt, + a little more to raise the temperature to cooling coil temperature.
    Beer can cold bandit stoled my superheat.

  5. #5
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    Jul 2000
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    Quote Originally Posted by incontrol View Post
    Are there any published reports on the cost of chiller usage vs ice bank. Customer is debating if it's cheaper to run chiller or ice.
    Calmac Ice Systems has been around for many years and has some excellent info on their web page. Click on the tab for Ice Energy Storage Benefits:

    http://www.calmac.com/

  6. #6
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    Jul 2006
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    Great thread guys, bookmarked
    You sure are cocky for a starving pilgrim.

  7. #7
    Join Date
    Jan 2005
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    Houston TX
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    Many good points brought up, but there is one definite negative. When your system is running to make ice at night and melt it during (peak hours) Lower KW rates at night generally and highest rates during the peak hours, you will save money. If however you need to run that chiller during the peak hours, you have to pay the highest peak rate and a major penalty cost.
    Once in a while everything falls into place and I am able to move forward, most of the time it just falls all over the place and I can't go anywhere-GEO

  8. #8
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    Jul 2000
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    Quote Originally Posted by ga1279 View Post
    Many good points brought up, but there is one definite negative. When your system is running to make ice at night and melt it during (peak hours) Lower KW rates at night generally and highest rates during the peak hours, you will save money. If however you need to run that chiller during the peak hours, you have to pay the highest peak rate and a major penalty cost.
    And depending on how the utility's rates are structured, you may bump the demand meter and wind up paying for that for the next year.

  9. #9
    Join Date
    Apr 2007
    Location
    uk
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    Agree with ga1279 one of the other negatives from experience has been the chiller is usually not sized for full load of the building due to the ice build and chiller equalising full load so if you develop any problems with ice storage, ice build or the controls quickly deplete the ice storage you will be in big trouble in high season. When everything is perfect yes you will save money but we don't live in a perfect world and systems break down and you will also end up running the chiller during peak charges.

  10. #10
    Join Date
    Mar 2014
    Location
    Northern Vermont
    Posts
    60
    Champlain College in Burlington, Vermont They have ice bank system. Theirs, I believe is a BAC system. I have toured their facility in the past very interesting. Maybe their Physical Plant would speak with you 802-860-2705 I worked on the refrigeration system on one huge one some 25 years ago I learned that you can not braze male or female adapters and expect them not to leak afterwards when they are on Black Iron Pipe. The theory is old like the farm "Sweet Water" tanks that stored the milk cans.

  11. #11
    Join Date
    Sep 2002
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    12,467
    Why not call Chester-Jensen or Colmac and see what they can offer? It must be a standard question for their sales departments. I installed some ice banks around the Philadelphia area - if the makers can't help you maybe I can call around and see what the field experience has been.

    One thing I can tell you - the system designers will always try to undersize you. Generally sizing for some calculated 'average load' - which means that you will always be running the chiller at peak KW rates at some points in the year. Especially as the system ages.

    The real keys to it are to make arrangements with the utility - ahead of time - to lock in some sweetheart off-peak rates on the we're-shedding-peak-loads-for-you sales pitch. And then sizing the ice banks for at Least the peak cooling load demands.

    Treat this as an industrial-process design project and not a comfort-cooling job and you will be much better off.

    PHM
    ------



    Quote Originally Posted by incontrol View Post
    Are there any published reports on the cost of chiller usage vs ice bank. Customer is debating if it's cheaper to run chiller or ice.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  12. #12
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    Aug 2009
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    Prattville, Alabama
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    Quote Originally Posted by Gibbo View Post
    Agree with ga1279 one of the other negatives from experience has been the chiller is usually not sized for full load of the building due to the ice build and chiller equalising full load so if you develop any problems with ice storage, ice build or the controls quickly deplete the ice storage you will be in big trouble in high season. When everything is perfect yes you will save money but we don't live in a perfect world and systems break down and you will also end up running the chiller during peak charges.
    This is the most commonly occurring problem I've seen. And when it happens, it's a biggie.
    I know of one owner that installed a new chiller, rated for full load, right next to a 1-2 year old smaller chiller on an ice storage system after being frustrated with finding ice was not made the night before, and then having a warm building all the next day.

  13. #13
    Join Date
    Jul 2006
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    One time when i was an apprentice i was doing a pm on a screw / ice bank , didnt know it was on a demand meter.
    Holy smokes did it hit the fan , energy company was cool, said just tell us when we did maintenance and let it slide
    You sure are cocky for a starving pilgrim.

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