AC, Calculating air conditioner size

Discussion in 'First Time Marijuana Growers' started by jzchillin, Apr 1, 2011.

  1. Pro tip - always undersize an AC unit, never round up.
     
  2. #62 Prankster, Feb 2, 2022
    Last edited: Apr 13, 2022
    Edit!!!!!!!!!!!!!!

    OKeee. This is all BULSHITT.




    I wanna be able to cool a room of about 61 cubic meter (2154 cubic foot) with a floor area of about 25 square meter (269 square foot) from 30 C (86 F) to 15 C (59 F) in 10 minutes.

    So air weighs about 1200 gram/cubic meter and has a heating capacity of 1.012 Joule/gram/K. So the equation becomes:

    61*1200*1.012*(30C-15C) = 1111176 joule/600seconds =1852 Watt = 1.852 KW

    And then an extra 16% for hot objects in the room: 1.852 * 1.16 = 2.15 KW


    Edit!!!!!!!!!!!!!!

    OKeee. This is all BULSHITT.

    So:

    2.15 KW = 2.15 * 3412.14 = 7336 BTU/h

    So thats 7336 BTU/h for an area of 269 square foot. Do you think its too much?

    I read that with an portable A/C you have to double that number.

    So that is 7336*2 = 14672 BTU/h for an area of 269 square feet and a ceiling at 8 feet

    So am I overshooting or not?
     
  3. well back in the day I didn't pay too much attention to the temperature b/c the room temp is approximately the ideal temperature, but back in the day you had to worry about heat which I'm quite familiar with HIDs which brought out a lot of heat which the police can detect which room you are growing in, now days the lights are custom built to provide less heat, I have 2 2000 watt grow lights in a tent with no ac no co2 canisters, nothing of the sort I grew decent marijuana back in the 90s, you are bringing this up which we know it's not true b/c we already done it without it
     
  4. well 61 degrees is too cold the ideal temp is 78 to 85 degrees, you remember the topic of the closet cultivator back in 1991? they was an article in high times every month reading it etc, which i am far ahead of you, which in reality if you people tried to grow without the forums you will see it's quite easy to grow, we didn't have forums we had books we read cover to cover & only performed the tactics of Ed Rosenthal, THC farmer tried to declare what ed said in his book for a lie & banned many of us that read the book, only to find out that spider farmer is dictating the forums to sell their products which no one needed in the 1st place, co2 canisters for starters you provide co2 we all do, if you have a wife and pets, no need for them b/c it will do more harm than good, my job is to get others to read from the founders of this environment, anyone wants to try to stand up to big Ed Rosenthal?
     

    Attached Files:

    • .jpg
      .jpg
      File size:
      120.3 KB
      Views:
      40
    • Like Like x 1
  5. #65 Prankster, Apr 13, 2022
    Last edited: Apr 13, 2022
    Nighttime temp. I work with a 24 h day average temp. 25C during Veg (24 hours 25C), 23C during Bloom (12 h, 26C and 12 h, 20C) and 21C (12 h, 23 C and 12 h,19C) during the last weeks.

    Keeping the vapor pressure deficit (VPD) at 1 during veg with a relative humidity of about 65-68% and during bloom a VPD of 1.5 with a humidity of 55% for ideal evapotranspiration and photosynthesis rate.

    Neglect my post about the A/C calculation. It is BS. In my country a room with a big heatload is cooled with 40-50 kW/m3. For every human an extra 0.12 kW. I count a growtent for about 4-5 humans.
     

Share This Page