
#1
Jul2408, 02:04 PM

P: 236

I'm going to fill a big container (3500 litres) with water. I'll use water from a hose, and boiled water, and I want to hit 40 degrees celcius.
Now, I figured that this was straight forward, Temperature in hose = 10 C Temperature of boiled water = 100 C ( 100 * X + (3500  X) * 10 ) / 3500 = 40 Which gives 1166 litres of boiling water. However, this assumes that 1 litre of 10 C water + 1 litre of 20 C water = 2 litres of 15 C water. In other words, that I can just add the temperatures together and then divide by the total amount of liquid. Someone (who unfortunatly was not able to provide a formula) said it is not as straight forward as that.. so, I'm looking for the formula for mixing liquids of different temperatures. k 



#2
Jul2408, 02:31 PM

Mentor
P: 11,984

How precise do you need to be? I guess you could take thermal expansion into account if you wanted to, but the simple weightedaverage method you used should be good enough for most applications.




#3
Jul2408, 02:36 PM

P: 236

Oh, ok then I am golden. I only need to be accurate enough to avoid boiling anyone that ventures into the pool :)
Thanks a lot. k 



#4
Jul2408, 03:30 PM

Mentor
P: 11,984

Formula for mixing liquids of different temperatures?
You could also do a test by making 3.5 liters first, using 1.17 L of boiling water.




#5
Jul2408, 04:41 PM

P: 236

Yeah, I'll do a small scale test first, to make sure.
Thanks again. k 


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