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Heat 600 cubic ft.

Kageey
Kageey Member Posts: 5
How many btu's is needed to raise 600 cubic ft a 40 deg F rise in 5 min?

Comments

  • SWEI
    SWEI Member Posts: 7,356
    Cubic feet of what, and in what kind of container?
  • Jamie Hall
    Jamie Hall Member Posts: 17,132
    And the time is irrelevant, except as it might relate to loss rate from the container...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Kageey
    Kageey Member Posts: 5
    Proof box in commercial bakery. Recovery time when doors are open to move product.
  • ChrisJ
    ChrisJ Member Posts: 11,978
    Kageey said:

    Proof box in commercial bakery. Recovery time when doors are open to move product.

    Don't we need to know the load on the oven, aka how much food is in it, and at what temperature vs the temperature the oven needs to be?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    .018 btu's per cubic foot per degree F differential. So if oven is kept at 120, and ambient is 70. then 50 X .018 X 600 = 540 btu's.

    How fast do you want to recover it??? Appliances are typically rated in BTU/HOUR, so if that 540 needs to recover in one minute, then the hourly input would need to be 540 X 60, or 32,400 btuH output. Input is dependent upon exchange process. If open flame in the box, it is 100%. If indirect, maybe between 70 and 80%.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    SWEI
  • Kageey
    Kageey Member Posts: 5
    Not an OVEN......The proof box operates at 120° f with a humidity of 70%. When the door(s) are opened to switch product out the temp drops about 40°. The Baker would like to speed up the recovery to appx 5 min. The existing immersion coils for humidity and the air heater rods are not adequate. 4500 watts/208 vac 3x1500 for each. Going to put a Sussman electric boiler for humidity recovery. Trying to figure the heat needed and the method to introduce. The heat Supply will have the 70% humid air passing over it.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    In addition to heating the air, you must also bring the mass of the product into the equation. ASHRAE has charts showing the thermal capacity of different food products.

    Is it problematic to have the humidity higher than 70%? If no, the steam generators may be a good means of recovery. If not, then you will have to introduce a dry heat to compensate.

    4500 watts is the equivalent of 15,300 btuH.

    15,300 / .018/60/40 = 354 c.f. of air heated 40 degrees F. Don't forget conductive losses thru the walls, and direct product loads.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    SWEI
  • Kageey
    Kageey Member Posts: 5
    I asked about the humidity also. Rolls, bread etc in box. Dripping condensate is not a good thing.
    By the way Thank You for spending your time on me.
    Appreciated.
  • ChrisJ
    ChrisJ Member Posts: 11,978
    Thank you, I learned something.

    I guess a proof box is used to help bread rise?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Kageey
    Kageey Member Posts: 5
    Yes. Product goes to proof box to rise and then the oven.