C
Chillville
Premium Member
Supporter
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There is a very precise and easy way of sizing chillers for use in cooling hydroponics reservoirs.
1. Calculate as accurate as possible how much water is in your hydroponics systems.
2. Turn on everything in the room that makes heat, do it in the hottest part of the day too. Basically let the room get to its max temperature.
3. Chill the system down to the desired temp. You can do this with bags of ice so that you won't be adding any additional water volume. This is important...once the desired temp is reached remove ALL the ice from the system. Circulate the water so the temp is equalized through the system. Turn on pumps, airstones etc.
4. Start a timer and write down the starting water temp, please be as accurate as possible.
5. At exactly 1 hr later check the temperature again and write it down.
6. Subtract the low temp from the high temp to get the temperature differential.
7. Use this formula below to calculate BTU needed….
gallons of water in system
X
8.34 (weight of a gallon of water)
x
temperature differential over one hour
------------------------------------
equals BTU needed per hour of chilling power
Example
If I had a system with 70 gallons of total water volume, I turned on my lights and got the room to 80 degreees. I started with 65 degree water....waited one hour and the temp was 70, so a 5 degree rise in temp.
70 x 8.34 x 5 = 2,919 BTU per hour.
3,000 btu = 1/4 ton
6,000 btu = 1/2 ton
12,000 BTU = 1 ton of cooling
Always give yourself a cushion, especially if buying a cheap chiller. They never put out their ratings, I always add at least 20% to the btu total when sizing. So with my example above I would figure about 3,600 btu which means I need a 1/2 ton chiller.
1. Calculate as accurate as possible how much water is in your hydroponics systems.
2. Turn on everything in the room that makes heat, do it in the hottest part of the day too. Basically let the room get to its max temperature.
3. Chill the system down to the desired temp. You can do this with bags of ice so that you won't be adding any additional water volume. This is important...once the desired temp is reached remove ALL the ice from the system. Circulate the water so the temp is equalized through the system. Turn on pumps, airstones etc.
4. Start a timer and write down the starting water temp, please be as accurate as possible.
5. At exactly 1 hr later check the temperature again and write it down.
6. Subtract the low temp from the high temp to get the temperature differential.
7. Use this formula below to calculate BTU needed….
gallons of water in system
X
8.34 (weight of a gallon of water)
x
temperature differential over one hour
------------------------------------
equals BTU needed per hour of chilling power
Example
If I had a system with 70 gallons of total water volume, I turned on my lights and got the room to 80 degreees. I started with 65 degree water....waited one hour and the temp was 70, so a 5 degree rise in temp.
70 x 8.34 x 5 = 2,919 BTU per hour.
3,000 btu = 1/4 ton
6,000 btu = 1/2 ton
12,000 BTU = 1 ton of cooling
Always give yourself a cushion, especially if buying a cheap chiller. They never put out their ratings, I always add at least 20% to the btu total when sizing. So with my example above I would figure about 3,600 btu which means I need a 1/2 ton chiller.
