Originally Posted by pjcampbell
300 gallons seems like a lot. Yes the goal is basically to cool at some compromise between speed and not wasting water.
A dudadiesel plate chiller says it'll do 10 gallons of wort in 5 minutes @ 68F water temp from 212F to 75F at 5gpm of water. That's only 25 gallons for 10 gal so 80 gallons or so for 1 bbl. Does that seem unrealistic?
I made an assumption based on mixing of fluids where everything ends up the same temp...or a worst case of how much water you would need....if you pump from one reservoir to another through the heat exchanger, you can reduce the amount of water needed, and end up with a hotter discharge tank. This would complicate the system a little bit (need for extra tanks) and limits your flexibility if anything goes wrong, or your chiller efficiency isn't as high as planned. It also doesn't lend itself to using the refrigerant during the chilling process, although depending on the size of the chiller, that may not matter as much.
There are some tricks that could be used, such as careful returning the hot water to the top and pulling off the bottom, hoping to keep the water temps stratefied, and minimize mixing.
I do use a 30 plate dudadiesel plate chiller with well water in the summer (around 65f) and I don't quite hit those numbers, although I think some of that is due to not be able to get 5 GPM through the chiller.