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  1. #1
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    Air Infiltration Question and help!



    I have a problem calculating the effects air infiltration has on a refrigeration system.

    I have 3 rooms at different temperatures all separated by a rough 7'X10' warehouse doors that are open approximately 90% of the time.. let's say 100% just for ease of calculation.

    One of the room is exposed to Outside Air Temperature, the doors are closed, but have small cracks roughly 18in^2 to 36in^2 on average.

    OAT = 110F
    Room1 = 55F (door closed 100% with leak area ~ 18in^2 - 36in^2)
    Room2 = 40F (door open 100 % with door area roughly 70ft^2)
    ROom3 = 30F (door open 100% with door area roughly 70ft^2)

    My question is how do I find the effect it has on the refrigeration system with all the leaks?
    How do I represent this into more of a $ and kWh savings?

    I know Q=U*A*dT and using the standard air infiltration equation...but i'm still at a lost.

    Anyone know any good equations or calcs to use and how to approach a problem like this?



  2. #2
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    Re: Air Infiltration Question and help!

    If the air infiltration is over and above the design amount for your refrigerating equipment, and it is warmer than the space you are trying to cool, then it will add to the load and your equipment will become undersized for the room/load.

    With the doors open 100% you are trying to cool the whole street/road/parking lot.

    Look at replacing the open doors with quick action doors http://www.stertiluk.com/stertilstok...pidroll330.asp
    I'm back on the Pale

  3. #3
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    Re: Air Infiltration Question and help!

    I have a Refrigerated Box Load Calculation worksheet that would be of some value to you. Message me your email and I will sent it your way.

  4. #4
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    Re: Air Infiltration Question and help!

    The system is actually over-sized because of the open doors. Room 1 @ 55F subjected to OAT @ 110F has loading dock, but the bay doors aren't sufficiently sealed of maintained. There are gaps everywhere and the insulation isn't the best. directly 20-30 ft away from the loading dock is a refrigerated space Room 2 @ 40F where the doors are open roughly 90% of the time. Behind room 2 is a freezer Room 3 @30F where the doors are open 90% of the time as well. A brand new refrig system was put in last year without addressing most of these issues, which only concludes that the system is vastly over sized to compensate for the additional heat, along with the internal heat load from lights, people, and machines. Just want to know the best calc method for this scenario and how to realize the potential savings.

    Passandscore. my email is michael.wc.lee@gmail.com


    Thanks.

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