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Hello.
I built a water chiller, and I don't know what its cooling capacity is because I am still learning about these things and it was not built perfectly.
If it cools 1 gallon of room temperature (25 C) water to 2 degrees celsius, then how many BTUh of heat was removed from the water?
We need to know how long it took to cool the water
4 minutes.
Sorry, the temperature the water was cooled to is actually 10 C. Not 2.
You don't say if your Gallon is US or 'Rest of the World' :D
As I work in SI lets assume the following:
1 UK Gallon = 4.8 Lts
1 US Gallon = 3.8 Lts
Using the formula Q = M C DT
Where Q = Power Required in kW
M = Mass Flow
C = Specific Heat Capacity
dt = Temperature difference of working fluid (T1 - T2)
To use the formula we need to convert your mass into mass flow, so 4.8/240 = 0.02l/s
Therefore, Q = 0.02 x 4.19 x (25-10)
= 1.257kW
Converting kW to BTU's = 4291.9334 BTU's
If it is US Gallons
3.8/240 = 0.01583
Therefore Q = 0.01583 x 4.19 x 15
= 0.995kW
Converting kW to BTU's = 3397.3538 BTU's
I'm assuming that this is a college question? ;)
Sorry, I meant U.S gallons. :)
This is for a water chiller that I built with a 50 foot 3/16" copper plain tubing condenser and a 20 foot 1/4" plain tubing evaporator, as well as a 1/4 HP R-134a fridge compressor.
I tried to cool air with the water but that failed so badly the air was just warm, and air flow was very slow, I could barely feel air coming out of the other side of the heat exchanger and the water the evaporator was in was barely cool. I don't understand if something went wrong when I started trying to cool air, but it cools the water when by itself fine (in the time I showed you).
This has been tremendously helpful, and it was kind of you to go to that trouble for me.
Thank you for helping me. :)
You answered my question, but now I need to figure out what is happening, and i'm not sure how.
I'm not sure if my chiller is performing as well as it should as I don't know what the BTU rating at 10 C should be.
Here is the compressor datasheet, it has a chart of the cooling capacity at different temperatures, but only up to -10, which is 20 C below the temperature I operated it at: http://www.fileconvoy.com/dfl.php?id...ad13bff139f15c
Does anyone know?
Quote:
Originally Posted by frank
To keep us all from changing all your data, try to stick to either imperial or SI. I know it is hard to do while sitting below the big American machine.