2700 Gal. Apple Dumper Tank Water - would like to raise from 47 degrees F to 70 degrees F

[HarperDog]

I am new to the forum. We are a Apple Packer . We have a Dumper , with 2700 gallons of water in it. We empty about
50 bins of apples in this dumper. These apples are about 34 degrees F. Our Dumper water is about 47 degrees F. We would
like to raise this temperature to about 70 degrees F. What I would like to do is circulate this water thru a heater and
to raise this temperature. The challenge is that we are always dropping in a 34 degree apple into this water. What is the
best way to calculate the needed BTU's to raise this temperature. What would be the best way to heat this much water up. It
is chlorinated , and can be dirty with stems , leaves , etc.

Thanks so much in advance.

 

[BigInch]

To answer that question completely, one would need to know how many pounds of apples you are dumping in, not how many bins.

The water part is easy. 2700 gal of fresh water is 22,500 pounds of water.
Temperature change of the water will be 70-47 = 23F
It takes 1 Btu to heat up each pound of water 1F, so you'll need 23 * 22,500 lbs = 518,000 thousand Btu to heat the water. Natural gas has about 1025 Btu/cubic foot, so that's around 505 cubic feet of natural gas.

Now the apples. I think that apples are probably about 90% water, let's say they are 100% water for calculation purposes, which should be conservative.

So for each 100 lbs of apples you need to heat them 70-34 = 37F
Now we can do it exactly as for water, Btu = 100 lbs * 1Btu/lb-F * 37F = 3700 Btu
So for every 100 lbs of apples you dump in, you'll have to burn another 3.6 cu ft of natural gas.

There are some inefficiencies in circulating water through a bath heater, so be prepared to burn anything up to say about 30% more fuel to account for heat lost up the burner stack.

That's just to get the water and apples up to 70F temperature. There will be a lot of heat lost from your water tank during all the time that you try to keep it at 70F. To find out how much heat that will take we need to know the shape of the tank, if it is insulated, if it is covered, if it is free standing, or set in the ground like a swimming pool, etc. If it is exposed to wind, how much wind and what the temperature is outside of the tank. I hope you're satisfied with just heating up everything and leaving it at that, cause the rest of it is a bit more work.