Root cellar / cool storage room?

   / Root cellar / cool storage room? #1  

ning

Elite Member
Joined
Mar 30, 2017
Messages
3,713
Location
Northern California
Tractor
Branson 3520h
I'd love to have a root cellar and have the desire and possibility the capability to dig & build one

but my concern is that I don't think that the ground here (norcal, 2000' elevation in the hills, fairly hot - often 90-95 15-25% humidity but rarely 100+ desert hot in the summer, kinda freezes but not a lot in the winter) stays particularly cool

It may be cool enough from midwinter on, but that doesn't help in the fall at harvest time when the top few feet of the ground are literally warm.

According to this graph for my approximate location things look good on the average from about Nov 1- Mar 15 (though not last year!), though a root cellar probably wouldn't be entirely at the "deep" level and instead would average a good amount higher due to part being deep and part being near-top plus a door etc (unless you go crazy nuclear fallout shelter with depth & airlock lol).

Overall I'm not confident that digging a traditional root cellar by itself would be worthwhile, though one could probably make it decent with insulation and active cooling during the the fall (though this makes it less enticing and definitely less "traditional").
1756140265692.png


so

Q) would a root cellar actually be 40-50°F more than a month or two if even that? I doubt it, but others may educate me, but remember this isn't Michigan or Canada

An alternative is, we have a "storage room" ~10x10 in the downstairs, probably the only part of the house that I'd consider a basement. It has three concrete walls - one to the under-the-garage direction, and one to the uphill, and a concrete slab floor = it's not going to be getting much warmth in half of the six sides. As it is, when the upstairs (main part of house, ceiling direction) is ~75-85° (actively AC'd on hot days, fresh airflow on less hot days) and the downstairs (other two walls) is 70-75° (not actively AC'd, but stays cool in general and also gets passive AC from cold air falling down the stairs from the upstairs AC) that room is usually mid-60s°. Still not nearly cool enough as-is for holding apples a while.

I'm thinking it may not take a ton to make this into a "reasonably cool" room, with closed cell insulation on the walls and ceiling, and a very small minisplit to keep it cool (and remove any remaining economical incentive to have a cool room). This would likely be cheaper and way easier than digging a root cellar + insulation + active cooling in the fall, together with being much more convenient as we already use it as a pantry/wine cellar/backpacking storage/oh just put it in there room...
 
   / Root cellar / cool storage room? #2  
That's a complicated set of questions, but here goes.

I grew up in a colder climate with root cellars, and yes, I agree, it is not likely to work for you in NorCal. I couldn't make one work here, even if I used a good north facing, shaded slope.

Creating a walk-in cold store is possible, just spend time researching your refrigeration cooler, as most home AC units aren't very efficient when the set temperatures are colder, and finally, part of a root cellar is that the air is turning over so ethylene doesn't build up, and prematurely spoil the fruits/vegetables.

Good luck!

All the best, Peter
 
   / Root cellar / cool storage room? #3  
Have you considered a Cool Bot?


I first read about them here on TBN, but have talked to a couple of orchardists who use them to store their crop in the fall.
 
   / Root cellar / cool storage room? #4  
Have you considered a Cool Bot?


I first read about them here on TBN, but have talked to a couple of orchardists who use them to store their crop in the fall.
That looks quite slick! It also looks as if they have an anti-freeze up function, which is often what does in smaller AC units. Nice find.

All the best, Peter
 
   / Root cellar / cool storage room? #5  
Ridgid foam insulation board on the surface will make a significant difference in the ground temperature 3 feet below.

I'm in the fridgid north (Vermont)
The water that comes up from my well is 55 degrees year round.
 
   / Root cellar / cool storage room? #6  
Since the root cellar will require aux cooling,the existing room sounds attractive and less work. A room air conditioner will be problematic below 60f. Freeze-ups, short compressor life and poor energy efficiency. If you have working knowledge of refrigeration or have someone that does I'd salvage a small refrigeration unit or even a used refrigerator or freezer components. Components of a commercial double door can handle the room if well insulated. If 300 cu ft is enough space, sealing off and dropping ceiling in part of room could be cooled with components from domestic refrigerator/freezer.

Scrap metal yard and scrapper guys who haul old appliances away for dealers are good source for old appliances. If you test 10 domestic fridges in a scrapyard , 5 would have failed t-stat, 2 would have clogged condenser coils(if all 10 had coils instead of using case) 2 would have bad compressor and one would be fully functional.

If you don't have wherewithal to utilize salvage components, here's something you might be able to use. I had my technicians carry an Inkbird controller to sub in emergency for fridge/freezer tstat until correct replacement could be obtained. $20-$30 and will handle home units, or with help of a relay,big commercial unit.
 
   / Root cellar / cool storage room?
  • Thread Starter
#7  
Since the root cellar will require aux cooling,the existing room sounds attractive and less work. A room air conditioner will be problematic below 60f. Freeze-ups, short compressor life and poor energy efficiency. If you have working knowledge of refrigeration or have someone that does I'd salvage a small refrigeration unit or even a used refrigerator or freezer components. Components of a commercial double door can handle the room if well insulated. If 300 cu ft is enough space, sealing off and dropping ceiling in part of room could be cooled with components from domestic refrigerator/freezer.

Scrap metal yard and scrapper guys who haul old appliances away for dealers are good source for old appliances. If you test 10 domestic fridges in a scrapyard , 5 would have failed t-stat, 2 would have clogged condenser coils(if all 10 had coils instead of using case) 2 would have bad compressor and one would be fully functional.

If you don't have wherewithal to utilize salvage components, here's something you might be able to use. I had my technicians carry an Inkbird controller to sub in emergency for fridge/freezer tstat until correct replacement could be obtained. $20-$30 and will handle home units, or with help of a relay,big commercial unit.
I agree that a dug-out root cellar isn't a good match here, as much as I like the idea and aesthetics of the concept, if the project gains traction it'll end up in that storage room.

I'm of the opinion that an easy-to-install package is worth spending some money on so I probably wouldn't repurpose a fridge, but it's a good idea.

I think that the storage room would likely be divided into a "colder" area for veggies & fruits wanting ~38° and a wine cooler area with a variable (probably manually) air exchange between them like in my sxs fridge (though that one is obviously automatic).

I appreciate the feedback here; and please understand that this is a "I like this idea" thing right now and if it gets the necessary approvals it will go on the "think about it for a couple years before finally doing it maybe list" ;)
 
   / Root cellar / cool storage room? #8  
If you can drill a hole maybe 6 feet deep you could then hang a thermometer in it and find out what your ground temp is at different levels. But if you need 5 or 6 feet of dirt on top of your ceiling then that could be very expensive to build.
Eric
 
   / Root cellar / cool storage room?
  • Thread Starter
#9  
If you can drill a hole maybe 6 feet deep you could then hang a thermometer in it and find out what your ground temp is at different levels. But if you need 5 or 6 feet of dirt on top of your ceiling then that could be very expensive to build.
Eric
If we had the right ground temps (see the graph on first page), I have a good hillside that would make it fairly workable, though it's by my barn about a hundred yards from the house (strangely enough it's flat around the house!)
 
   / Root cellar / cool storage room? #10  
see the graph on first page
Graphs are all well and good but real world measurements are sometimes quite different. Where I live this is certainly the case because we are fairly close to the Salish Sea which moderates temps.
Eric
 

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