Mini Split Questions

[MJockey]

I'm looking to heat and cool my new garage with two 48000BTU multi zoned mini split systems. I would like to use one of the rooms like a root cellar. It will need to be kept cold and moist.

Questions:

How low can I set the temperature on the wall unit? Can the temp be set low but keep the humidity set high?

On a multi zoned system, can one zone be set to cool while the others are heating?

Thanks for any input.

 

[Kaizen]

your location would be needed to answer this well.
my first thought is you might as well just get a big freezer you can keep at 35 degrees.
the physics behind cooling equipment is they remove humidity. no going around that.
yes one zone can heat and one will cool however each one has a temp it will not kick cooling on. its fairly high I believe. might want to look it up before you proceed.

 

[Fixin'Stuff]

Air conditioners, by their very nature, remove humidity from the space. As the wet air moves across the cold coils, the water condenses out. Maybe you could feed that condensate into a humidifier instead of dumping it outside? You would still have to rig up some type of condensate pump as a failsafe, in case the humidifier tank gets too full.

 

[Fixin'Stuff]

Oh yeah, how ginormous is this garage that needs eight tons of a/c?

How cold do you want to keep the root cellar?

 

[turbowoodworker]

Square feet for each area and location of shop, please.

 

[Ohmthis]

Its been answered about the humidity, but not all units can heat and cool at the same time ive put in daikin and mitsubishi. One head can be set for heat and one for cool, but one side has to satisfy before you would get any output from the other.
Fixin stuff, 48,000 btu is equal to 4 tons.

 

[Heel2toe]

^The OP actually mentioned using 2 48k BTU units...

I too am wondering how large of a space this would be for...but as others have mentioned Im not sure a minisplit will work well for your root cellar needs. I'm not to familiar with them however I'd imagine the temps need to stay a lot cooler than ~60 degrees which is probably the cutoff for most mini splits. IIRC my Mitsubihsi unit goes down to 61 degrees.

 

[Fixin'Stuff]

Fixin stuff, 48,000 btu is equal to 4 tons.

Read the OP just a bit closer:

"I'm looking to heat and cool my new garage with two 48000BTU multi zoned mini split systems. "

 

[justinjoyal]

Better be one huge garage !

 

[pseudorealityx]

So... there's some truth above, but it didn't get the WHOLE truth.


While it's true that air conditioners to pull out moisture, they still discharge saturated (100% RH) air. As that air heats up, the ACTUAL moisture level may increase, but the RELATIVE moisture will actually fall, because warmer air can carry more moisture.

What that means is that if you set the thermostat for 60 degrees in your space, you're going to end up with 70% RH. For winter operation, you may want to add a humidifier.

If you're concerned it's too dry, just drain the condensate into a bucket that sits in the room... then you'll never actually remove moisture from the room.


For systems that can simultaneously heat and cool, you're looking at commercial grade systems. Typically, they are referred to as "Heat Recovery" systems in the industry. The big names all make them... Mitsubishi, Fujitsu, Daiken, LG, etc. The small residential brands won't be able to do it. It comes at a cost, fwiw.

 

[Ohmthis]

Read the OP just a bit closer:

"I'm looking to heat and cool my new garage with two 48000BTU multi zoned mini split systems. "

DOOHH!!! Sorry, no more skimming

 

[Fixin'Stuff]

DOOHH!!! Sorry, no more skimming

Done it myself. I'm still in awe of a shop that needs 8 tons of cooling....

 

[MJockey]

Okay some more info. The Garage is located in east Tennessee. The garage size is; 1st fl: 48' x 50' x 13' tall, 2nd fl 48'x 18' x 8' tall. The 1st floor will have an auto bay area (47 x 37 x 13), a 12 x 13 workroom with a 6'x7' open breezeway to the auto bays, an unheated / cooled 12 x 22' tractor storage area, and the cold room will be 12 x 13 x 10 before insulation and cooled to fridge temps.

The original plan was to use 1- 4 Ton unit for the auto bays and work room and the other for the second floor and cold room. After more research, I'm going to need a stand alone (separate unit) rated at least 24,000 BTU for the cold room. I will use a CoolBot to get the mini split to cool the room to 38 -40 degrees.

I still need to figure out how to cool / heat the auto bays, workroom , and 2nd fl. based of calculation from a online BTU Calculator, I need 4 to 5 Tons for the Auto bays and workroom and another 2 Tons for the 2nd floor. I like the efficiency of Mini Splits but that means I looking at 3 systems now.

A few photos:

 

[LS6 Tommy]

You're not going to be able to acheive your "fridge temps" with any type of HVAC system. You need refrigeration equipment.

Tommy

 

[MJockey]

You're not going to be able to acheive your "fridge temps" with any type of HVAC system. You need refrigeration equipment.

Tommy

Check out the CoolBot site, lots of user getting fridge temps with window AC units.

 

[chrispyny]

Flippin A man, epicly epic garage. So jealous. Good for you. Keep us posted on which way you go.

 

[LS6 Tommy]

Check out the CoolBot site, lots of user getting fridge temps with window AC units.

Works great until the compressor slugs. I 've seen three Coolbots in my life. All three crashed a compressor in less than a year...

Tommy

 

[MJockey]

Works great until the compressor slugs. I 've seen three Coolbots in my life. All three crashed a compressor in less than a year...

Tommy

Do you remember what brand AC compressor? I know the manufacture recommends certain brands and not others they have had issues with. That said there is 10 pages of 5 star reviews from verified purchasers on Amazon. There was one review from a guy that has installed 18 unit over the last 7 years and haven't had one complaint. He uses LG units.

 

[Kaizen]

so you're going to go with that guy on the internet instead of everyone here that has said use refrig equipment. good luck.

 

[MJockey]

so you're going to go with that guy on the internet instead of everyone here that has said use refrig equipment. good luck.

Sorry but commercial refrig equipment to cool 1320 cubic feet of space is not in the budget. So I started looking for other option. My decisions to go the CoolBot route is based on 100s of positive reviews by owner/user of it.

No offence but aren't you just some "guy on the internet"? Do you have any first hand experience setting up/ building walk-in coolers? If so I like to hear more about it and what equipment you used and what it cost.

 

[Kaizen]

Sorry but commercial refrig equipment to cool 1320 cubic feet of space is not in the budget. So I started looking for other option. My decisions to go the CoolBot route is based on 100s of positive reviews by owner/user of it.

No offence but aren't you just some "guy on the internet"? Do you have any first hand experience setting up/ building walk-in coolers? If so I like to hear more about it and what equipment you used and what it cost.

Yes I am just a guy. just like the 100 leaving positive reviews. My point is you want a specifc answer and all the other guys on this thread are pretty much disagreeing with you.
Well yes since you asked when I built my wine cellar and researched the tons of cheap diy solutions to cooling it I saw all kinds of stuff like you are talking. and yea I saw tons of positive reviews. In the end I purchased a cooling unit for my wine room. yes it costs money but no more then a minisplit that i'd have to rig to run colder then normal or the mold issue from using a window ac and pumping moisture into the rest of my cellar.
I also helped a friend retrofit a restaurant freezer to his cellar for a beer and cider storage. he bought it at an auction for a grand and we had to take it apart, move it, and reinstall. then he had a hvac guy come out and get the lines running. no not cheap but neither is blowing your minisplit compressor after a few months.

 

[MJockey]

when I built my wine cellar and researched the tons of cheap diy solutions to cooling it I saw all kinds of stuff like you are talking. and yea I saw tons of positive reviews. In the end I purchased a cooling unit for my wine room. yes it costs money but no more then a minisplit that i'd have to rig to run colder then normal or the mold issue from using a window ac and pumping moisture into the rest of my cellar.

Any chance you have a build thread on your wine cellar?

 

[Zeke]

Any reason to want specifically a 'split' system?

There are many choices with package units; side mount, roof mount, you can even run a supply duct distribution to key areas. The only reason splits are used (mini and otherwise) is for central distribution in a complex structure like a house with many rooms. You do want the return air taken from the common and center of the house like a hallway.

In a big *** building like yours, you can simply park a unit on the side or in back and take the return air in from there.

How about this monster?

 

[larry4406]

I'm interested in walk in coolers so please be the guinea pig and post all the success and/or failures. I want to build a keg room for home brew in the basement, so I wish you the best and post away.

 

[Kaizen]

Any chance you have a build thread on your wine cellar?

No I did that 15 years ago. Wouldn't have helped you much as you have much larger cooling needs.


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