I’d like to discuss an idea for a temperature controlled fermentation chamber. Would it be possible/worthwhile to use the cold winter air to cool an insulated indoor box for the purpose of controlling fermentation temperatures? I envision a simple duct between the chamber and outside with an inline fan, controlled by an electronic temperature controller, and some type of flap to prevent air movement unless the fan is on.
In the bigger picture, why can’t we use cold outside air for our refrigeration needs on our kegerators and even household fridges? Just imagine how much energy this could save if implemented on a global scale anywhere there’s a cold winter!
It just seems like some kind of massive collective insanity to me to use precious energy to cool a space inside of a heated space in winter!
I’m sure it has been done. My big ideas usually turn out to have been already thought up by someone else.
Sometimes called Passive Refrigeration. It has been available for commercial coolers for awhile.
I roll my eyes when I hear about people loosing food during a winter storm because they lost power to the refrigerator. It’s cold outside and nature is literally throwing ice at you. Put your perishables in the garage! I do it all the time when I make a huge meal like chili. Even if there was room in the fridge (which there probably isn’t) I’d just be putting a big hot mass in there and then paying to chill it.
Anyway - son of a fermentation chiller is basically what you’re talking about. It uses frozen water bottles but could easily be rigged to use outside air.
Odell does that on their beer cooler in the brewery. When the temperature drops down to fridge temps the temperature control system shuts off the compressor and opens windows in the cooler. It’s cold enough of the year that they can do that frequently enough that it made sense to invest in a system that can do that.
However, here in Texas that would be wasteful because we are lucky if we have a month where it is cold enough to do that. The summer gets too hot for even my saison fermentations, which I usually do at a balmy 90F.
Passive refrigeration. Appropriate.
So, theoretically, if I wanted to move cold air from one source to another would say, 8’ of insulated 3/16" tubing and an aquarium-type air pump be sufficient to move enough cold air to cool a refrigerator, assuming 32f source temperature? I assume I would need a warm air return.
As far as building systems (as opposed to refrigeration) it’s pretty common to have a system that uses cool outside air to modulate interior temps and minimize A/C in the “shoulder” months when seasons are changing. You can also use a heat exchanger to recover heat from exhaust air to pre-heat intake and reduce heating costs.
Not so common in residential (single family) uses. At least in my experience.
In the bigger picture, trying to do this for a household refrigerator would require automation, duct work, etc. that would probably make it not cost effective. Today’s energy star appliances are pretty efficient.
I do like to use outside cold air to cool soups, chili, or whatever needs to go into the fridge. I would worry about leaving those outside overnight what with the squirrels and racoons. I’m not sure how active possum are in the winter, but we’ve got too many of those, too.
I think 4" dryer vent would work better that 3/16" tubing. Cooling efficiently is about the volume of air you move. You want to move a lot of air in a short time and then let it sit until the temp controller sees the temp rise again.
IMHO at least.
Paul
I lived in an old house in Cincinnati years ago that had a galvanized box built into the kitchen wall under the window where you could keep food cold in the winter months. It was basically a box hanging outside the house with sliding door access from inside. Perhaps you guys in cold climates could include one of these in your remodeling plans.
If my house had one of those, it would’ve got torn off, insulated and dry-walled in the remodeling plans. I don’t like drafts.
However, I do have an unconditioned (in the winter) room in the basement that keeps all my wine and beer at steady cellar temps. Summer time requires an A/C. But for the wine, I could ventilate it to outside air and have a freeze-ass walk-in lagering chamber. I did that one year. It was a steady 40 degrees in there. However, it being below the kitchen caused the floor to be cold.
I’ve definitely thought about that but haven’t wanted to put the hole in my wall. My thoughts are to build an insulated box like a “Son of a Fermentation Chiller” or one of the various versions with a fermentation chamber and then some sort of baffled cold air chamber connected to the outside world with a flapper to keep the cold air from blowing in when it wasn’t called for and a fan to push it in when needed. I think the exact design depends on how much of a temperature differential you are talking about. In places with extreme cold it would be important to make sure there is a good seal between the fermentation side and the cold side so you do not inadvertently freeze your beer :0
They need to make it into a kegerator
With taps built into the door.
Love the plywood shelf.