I'm not concerned about the weight, I have had over 2000 lbs in the freezer with no problems.

My question is about the cooling capacity.

I am cooling 20 gallon of fluid from 90 to 40 or a 50deg change. At 8.5lb per gallon I figure this will take 8500 BTU to accomplish this.

Using the thermal mass of the water to do the rapid cooling, 200 gallons of water at 7.5lbs per gallon starting at 32 and raising to 40 would be 12000 BTU's plus the 3000 BTU's of the compressor.

A pump will circulate the water to ensure uniform wather temp and an external cold control will control the compressor with the probe in the water.

Are my calculations correct?
How quickly could I expect the fluid in the glass containers to reach 40 deg?
Can you think of a better way to accomplish this?