Energy Consumption - Glycol Chiller or Fridge?

[gustavohmsilva]

Hi guys!

I'm having a little problem with my new DIY plans and would like some help with it. Could you guys help me a little?

I make small batches (15 gallon each) and have only one fridge, which is a problem, a HUGE problem (because I love brewing, who doesn't?). But instead of buying a new fridge, I'm considering use a small bathroom that nobody uses at home (my fermentation fridge is in there now) as a cold chamber. This would help me keep up to twelve 15 gallon fermenters, but I'm afraid that the energy cost will rise as hell.

My question is: considering I'm gonna insulate the bathroom from top to bottom with 2 inches of Styrofoam, and use an air conditioner to chill 10 gallon of glycol circulating in the fermenters. Which would consume less? Using fridges or this air conditioner + glycol fluid rig?

I have no idea how to measure that because both of them will be turning on and off all the time, maybe some of you guys had made this change (from fridge to glycol DIY chiller) in the past and measure the electric bill price changes...

 

[DeBrewer]

I am not sure that this can accurately be answered. Off the top of my head you could loosely gauge it by the BTU needed in each approach and then choose the lesser of the two? I realize that energy consumption for a BTU in a refrigerator as opposed to an air conditioner are different, but that seems to be the easiest measure to compare.

 

[helterscelter]

I am not sure that this can accurately be answered. Off the top of my head you could loosely gauge it by the BTU needed in each approach and then choose the lesser of the two? I realize that energy consumption for a BTU in a refrigerator as opposed to an air conditioner are different, but that seems to be the easiest measure to compare.

I'd say it could be measured with something like a kill-a-watt if you had (or knew someone(s) who had) both options, but I think there would still be some variance due to the minor differences in the installation/insulation.

 

[Spellman]

Offhand without actually crunching the numbers I would say a glycol will end up using less in the end. Even though it isn't really the same comparison, before I built an actual chiller I used a fridge to chill my reservoir tank and pumped that through jackets. I had a heck of a time keeping the tank cold, and the fridge would run non-stop. Seemed to me like there is a bit of energy loss when using air to cool liquid, instead of liquid to cool liquid. (I'm sure someone else can put that more scientifically and eloquently + comparing a 150 btu fridge to a 5,000 btu ac isn't really that fair either). Another point, instead of cooling the volume mass of air and the wort, you would just be cooling the wort. I definitely would do plenty of insulation around the fermentors though, I highly suggest 4 layers of reflectix if you plan to crash cool. And my final and probably most important point to make, if you are spending that much time on brewing, why on earth would you want to lump all of those different fermentations together under one temp? I know of one local brewery that did do just that and they did not like it at all. On my 10g batches I have them all separated out and have the ability to have unique temp profiles running independently. I could have a saison running at 90 right next to another beer that I am cold crashing at 33.

 

[helterscelter]

Offhand without actually crunching the numbers I would say a glycol will end up using less in the end. Even though it isn't really the same comparison, before I built an actual chiller I used a fridge to chill my reservoir tank and pumped that through jackets. I had a heck of a time keeping the tank cold, and the fridge would run non-stop. Seemed to me like there is a bit of energy loss when using air to cool liquid, instead of liquid to cool liquid. (I'm sure someone else can put that more scientifically and eloquently + comparing a 150 btu fridge to a 5,000 btu ac isn't really that fair either). Another point, instead of cooling the volume mass of air and the wort, you would just be cooling the wort. I definitely would do plenty of insulation around the fermentors though, I highly suggest 4 layers of reflectix if you plan to crash cool. And my final and probably most important point to make, if you are spending that much time on brewing, why on earth would you want to lump all of those different fermentations together under one temp? I know of one local brewery that did do just that and they did not like it at all. On my 10g batches I have them all separated out and have the ability to have unique temp profiles running independently. I could have a saison running at 90 right next to another beer that I am cold crashing at 33.

That is an awesome set up. Do you have a build thread for it?

 

[gustavohmsilva]

And my final and probably most important point to make, if you are spending that much time on brewing, why on earth would you want to lump all of those different fermentations together under one temp? I know of one local brewery that did do just that and they did not like it at all. On my 10g batches I have them all separated out and have the ability to have unique temp profiles running independently. I could have a saison running at 90 right next to another beer that I am cold crashing at 33.

Just to clarify Spellman, I live in Rio de Janeiro, with a 109ºF summer. That's why I would like to create a cold chamber. Not to put all the fermenters in a standard temp, but to avoid that the 109ºF in the summer make my future Glycol Chiller work too much. The idea is to:

1 - Use a Temp Controller to keep the liquid of the Glycol reservoir 50ºF below the coolest target temp of the any fermenter.
2 - Use one Temp Controller per Fermenter, circulating the Glycol to keep them in their specific desired Temperature.
3 - Use an additional Temp Controller managing a Fan and an extra pump, to keep the Ambient temp inside the cold chamber exact the same of the higher temperature worker fermenter.

This way, I'm not only capable to avoid a 109ºF summer spike like we always have, but also keep the temperature in the recipes different.

I was thinking, about the third topic above, to do something like this (but with Glycol):