Chiller Sizing - Lagers

[jgmjackson]

Hi Everybody -

I submitted a hypothetical scenario to ProChiller for a brewery that does a large percentage of lagers and got a very large chiller recommended. I am not questioning their math - I am looking for ways to reducing the wort chilling load, which is driving the size of the chiller.

My question - Assuming a "worst case scenario" of a double brew day on a 15bbl system, what ways are there to help so that the chiller load isn't nearly 200k btu/hr when cooling from 85f to 52f in 60 mins? I am assuming it will be prechilling some amount of water to help with 1st stage cooling in the HEX but hope the forum can offer up some help from experience.

I have attached the sheet for reference.

Thanks,

John

[jcrjustin]

I would not recommend using your chiller to directly cool wort. Every time you knock out a batch of wort you will be warming up all of you tanks that are calling for cooling and putting tremendous stress on your chiller. Why not pre chill all you water to the heat exchanger or use a cold liquor tank? What is the ambient temperature of your incoming water?

[jgmjackson]

Yeah, that makes sense. Directly chilling the wort is what is making that load calculation so huge, so cutting that out of the equation gets me way down. So would a 2 stage HEX be the way to go with city water then cooled water to get the wort down to 52f? Accounting for double brew days, I'm imagining the CLT is going to have to be pretty big.

I am in the LA area and summer water temps can get on the warm side (estimating 75f worst case).

[jcrjustin]

Your heat exchanger supplier should be able to size a 2 stage unit with your specs. Much cheaper than a larger chiller. Plus with using just water, you can reclaim the hot effluent for other processes in your brewery.

[jgmjackson]

Yes, they are sizing it for a 2 stage HEX with the chiller doing the duty of dropping from 85f to 52f (at least that's how I read it). That is still quite a load and that's where I am hoping a large CLT can take its place in that duty.

I put a 15bbl CLT into the calculation as a hypothetical, just to see what the load would be. It would likely need to be larger to handle the 2nd stage of the HEX for back to back lager brews. I will ask them if they can run that scenario.

[jcrjustin]

You can also get a second smaller heat exchanger that will pre chill city water for the second stage of the larger heat x.

[whaleyproducts]

Calculations

15 BBL = 465 gallons

465 gallons x (85F - 52F) x 8.5 lb/gal = 130,432.5 btu/hr would be your wort cooling max load.

I would recommend using a cold liquor storage tank (water) somewhere in the 500gal to 1000gal range, and have it slowly pre-cooled down as cold as possible by the glycol chiller during your down-time (overnight & after your first brew of the day), when you're not wort-chilling. Making use of your down-time, and banking as many btu/hr possible by slowly cooling a larger cold liquor tank, will allow you to have a bunch of stored up btu/hr to unload on the shock-effect wort cooling application.