An insane idea for temperature control

int0x2e

Member
Dec 9, 2015
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I already know my idea is crazy, but please tell me if it also makes any sense at all.

My rack is currently in my office, but the noise is beyond what I (and the wife) can bear. I've been given permission to move it all to the garage, but since I'm located in a very sunny and hot part of the world, the garage is pretty hot in the summer (30C+ average, 40-45C peaks).
My idea is to seal-off a part of my garage, add a small split AC system (sized to handle about 1.5X - 2.0X the rack's estimated heat load), and move my rack there.
I want to set the AC to 28C-30C, to minimize costs while keeping the equipment reasonably happy, but I predict that the AC will have frequent stops and starts, which means the equipment will go through many temp cycles as well.
It might be beneficial if I could add a lot of thermal mass to the server chamber, to smooth out these temp cycles. I also want to do it as cheaply as I can.

And now to the insane bit - I'm thinking of filling up a lot of that space with large water containers (think 55-gallon drums).
They're cheap and should have decent thermal mass (imagine multiple metric tons of water in that room).
They're also very bad to have around all my equipment if they ever leak, or god frobid - burst.

So - insane, right?
 

MiniKnight

Well-Known Member
Mar 30, 2012
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I'd pass on water next to your rack. Do you have plan to leverage free cooling in cooler months? What are you doing for air filters.
 

j_h_o

Active Member
Apr 21, 2015
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Put some giant rocks or bricks in there for higher specific heat capacity.

What happens in the winter? What's your year-round temperature range? Do you ever freeze, too?
 

kapone

Well-Known Member
May 23, 2015
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Yup. Insane.

If you can't cool servers/rack full of "whatever", properly, in a safe manner, don't buy the equipment in the first place. I know it sounds harsh, but somebody's gotta say it.
 

Spartacus

Well-Known Member
May 27, 2019
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Austin, TX
How much equipment are you talking about cooling/how many BTU? Does your garage have any windows already?
Even if it doesn't a better route might be to cut a hole and install a window A/C unit that is sized appropriately on the side of the garage.
Then box off the area around the A/C and rack to make a server room (with insulation if possible). Those window units are super cheap, and provided it doesn't get insanely cold during the winter, insulation and heatload should keep everything good during the winter too (you could always get a unit that heats and cools if it does and set it for 30c during the summer and 15c during the winter).
 

chaoscontrol

Member
Aug 15, 2019
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My rack has been in the garage for 5 years now. During summer it gets around 45 celcius and in winter down to 5 celcius. The temperature isn't a problem but do keep an eye out for humidity. Keep it as low as possible during the temperature swings.
 

int0x2e

Member
Dec 9, 2015
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I'd pass on water next to your rack. Do you have plan to leverage free cooling in cooler months? What are you doing for air filters.
I guess you're probably right. I did also consider using oil (used motor / cooking oil) instead of water, but I guess either one is still insane :)
I wasn't quite thinking of using free cooling before, but I guess I should look into adding external air intake and exhausts with some fans. Good idea!

Put some giant rocks or bricks in there for higher specific heat capacity.

What happens in the winter? What's your year-round temperature range? Do you ever freeze, too?
I love the rock idea! Will see what I can do. If I can pick up masonary blocks for cheap, that might make more sense so the small server room remains relatively clean.
I'm attaching a chart of the year-round average temps, but I'm pretty sure these don't capture the daily extremes at all. In the peak of summer, noon time can easily reach 40C, even 45C sometimes, and in winter we get dips below 10C, but never below freezing. Humidy is quite high (~10KM from the sea), especially in the summertime.

Yup. Insane.

If you can't cool servers/rack full of "whatever", properly, in a safe manner, don't buy the equipment in the first place. I know it sounds harsh, but somebody's gotta say it.
I can cool them for sure, I already do. Having said that, since this is the first time I'm setting up the space for the homelab somewhat properly and can do some planning, I'm trying to optimize my power use while trying to also not put the hardware through needless thermal stress...
The idea wasn't a way to handle heat load I can't handle, it was to smooth out the temp fluctuations to keep the equipment safer.

How much equipment are you talking about cooling/how many BTU? Does your garage have any windows already?
Even if it doesn't a better route might be to cut a hole and install a window A/C unit that is sized appropriately on the side of the garage.
Then box off the area around the A/C and rack to make a server room (with insulation if possible). Those window units are super cheap, and provided it doesn't get insanely cold during the winter, insulation and heatload should keep everything good during the winter too (you could always get a unit that heats and cools if it does and set it for 30c during the summer and 15c during the winter).
I'm planning for what I have with room to grow, so aiming for under 3KW, which with some headroom would be under 12K BTUs. I already plan on having a small lightly-insulated part of the room with its own split AC unit sized for the heat load from the servers and some losses on cooling the room itselft.

Set the thermostat to start/ stop in a narrow band.
I'm afraid for the small split AC units I can find locally that's not an option. I wish it was possible though!

My rack has been in the garage for 5 years now. During summer it gets around 45 celcius and in winter down to 5 celcius. The temperature isn't a problem but do keep an eye out for humidity. Keep it as low as possible during the temperature swings.
This is great to hear! That's a very similar profile to my temp range.
Are you cooling your garage at all?
Do you rely on servers that have very high airflow or just don't care?
Any issues thus far?
Any tips on controlling humidity?

Thanks again everyone! :)
 

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Philip Brink

New Member
Sep 14, 2019
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Perhaps a simple solution is reducing the noise and leaving it place. Depending on the equipment, fans could be exchanged, noise dampening, higher u sizes to increase fan diameter, lower noise psu, etc.

If the server count is low, it may be a cheaper option and easier to manage.

I have gone as far as using custom watercooling solutions with low speed/noise fans. The risks are pretty low with modern option, but it is there.
 
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SRussell

Active Member
Oct 7, 2019
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How much are you budgeting for this?

You could build a room within the garage. Insulate the room with closed cell spray foam and add a small AC unit. The same could also be accomplished with an outside shed that is insulated well.
 

chaoscontrol

Member
Aug 15, 2019
42
10
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This is great to hear! That's a very similar profile to my temp range.
Are you cooling your garage at all?
Do you rely on servers that have very high airflow or just don't care?
Any issues thus far?
Any tips on controlling humidity?
Not cooling the garage at all. Rely purely on how much heat each server is able to lose by itself. My machines are pretty idle most of the time so I didn't have any problems with airflow.

No issues whatsoever but I will be putting the rack inside sometime next year just because I tire of going down to the garage every time something is up (my workspace is on the attic).
 

cageek

Member
Jun 22, 2018
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Sounds very similar to a wine cellar. I remember seeing pictures of home-built wine cellars (closets, under stairs, basement, garages, etc.) in forums on the internet. Seems like similar problems - temp. & humidity - though of course not the same settings and no heat source inside a cellar. But, the construction techniques might be worth looking at, especially insulation, for some ideas.
 

Smbaker

New Member
Oct 9, 2019
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... but I predict that the AC will have frequent stops and starts, which means the equipment will go through many temp cycles as well.
Many mini splits have inverter-driven variable speed compressors. Rather than cycling the whole unit on and off. they can slow the compressor and deliver reduced cooling.
 
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Tom5051

Active Member
Jan 18, 2017
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make the sever quieter. for the price of a split system and the cost of running it, you could make a sound proof case and decent fans that dont make shed loads of noise. The garage is the wrong place for a server.
 

Lost-Benji

Member
Jan 21, 2013
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The arse end of the planet
Stopped reading the replies after a few about silly ideas. Aircon will keep the room fine, the gear will have enough thermal mass to level out the tiny fluctuations. Just build the room (Foam Coolroom Panel is great) and fit small air-con. Otherwise, silence the rack and keep plenty of air-flow through a dust filter.
 

funkywizard

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Jan 15, 2017
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Maybe two window AC units, set to different temperatures. One will always be running (set to 60F) so should keep temp fluctuating less.

If you do want to use thermal mass, there needs to be an efficient way for that mass to have an impact on the temperature of the air in the room. Just having sealed containers of water won't do that. A radiator with fans going over it, with a large water resevoir, may have something like the effect you are looking for.

However, your better bet is to look for an A/C unit that supports operating the compressor at partial load. The high efficiency mini split units are more likely to support this than other types of AC units. Then you have the fan "on" instead of auto, and, hopefully, the compressor will keep itself at a relatively steady partial load as necessary to maintain temperature.
 

F1ydave

Member
Mar 9, 2014
133
21
18
I already know my idea is crazy, but please tell me if it also makes any sense at all.

My rack is currently in my office, but the noise is beyond what I (and the wife) can bear. I've been given permission to move it all to the garage, but since I'm located in a very sunny and hot part of the world, the garage is pretty hot in the summer (30C+ average, 40-45C peaks).
My idea is to seal-off a part of my garage, add a small split AC system (sized to handle about 1.5X - 2.0X the rack's estimated heat load), and move my rack there.
I want to set the AC to 28C-30C, to minimize costs while keeping the equipment reasonably happy, but I predict that the AC will have frequent stops and starts, which means the equipment will go through many temp cycles as well.
It might be beneficial if I could add a lot of thermal mass to the server chamber, to smooth out these temp cycles. I also want to do it as cheaply as I can.

And now to the insane bit - I'm thinking of filling up a lot of that space with large water containers (think 55-gallon drums).
They're cheap and should have decent thermal mass (imagine multiple metric tons of water in that room).
They're also very bad to have around all my equipment if they ever leak, or god frobid - burst.

So - insane, right?
Crazy/Insane is where most of us live on here. :D

Did you ever follow through with this?

Lots of people do fan swaps to lower the sound level. I have done that but when you have multiple devices even the quiet hum adds up.

I personally wouldn't do rocks/blocks or water/oil jugs. Consider using a passive method exterior with active cooling.

Design ideas:
1. Mini-splits are very efficient to run. I wouldn't get caught up on Seer rating. Get one with an inverter so that it can step down the compressor/fan speed, leave the setting fan always on. A/C's aren't designed to run 24/7...I would oversize it.

2. Have a backup ceiling exhaust fan with temperature gauge in case the a/c goes down.

Build:
3. The exterior could be cheap sheets of wood or drywall...however you want it to look/match in the garage. I would personally build it like a closet for when you move someday. Consider using a thermal break on the interior, exterior or both. The sound/home theater industry makes tracking for a very similar purpose. I personally would just do some cheap plastic spacers and polyurethane caulk (if you use sheathing/sheets like OSB or mixed material make sure that it is compatible). This way the thermal load would only transfer from the outside through these small points of contact. Consider something that offers a vapor barrier as well. Like tyvek, poly-iso foam board taped, vapor barrier liquid paint etc.

Personally, I would use poly-iso foam board, taping the seams and drywall over it. (two birds one stone)

4. 2x6 or 2x8 wall thickness depending on temperature isolation needed. In the US we have a product called T-stud that offers over a 99+% thermal break and it costs nearly the same as a normal stud, but aluminum stud could work well here.

5. Insulation, Rockwool would work well especially if bugs or termites are a problem for your area. They won't tunnel through it like foam insulation. I would use smaller thickness insulation to further guarantee no thermal transfer to your interior wall. Calculate what R-value you need to isolate the room as needed and size the wall appropriately.

6. The interior should be mounted with a thermal break too, meaning a gap between the wall/sheathing and stud. I personally would use sheets of aluminum or aluminite for the interior wall.

7. Use an exterior sealed/insulated door.

Extra's/over the top
8. I would probably place a small exhaust fan inside the wall for a just in case scenario.

9. I would install light vertically across from the rack for ample lighting.

10. Add in contactors to power green/red lights on the exterior of the closet to show when the a/c is running, if exhaust fan 1 or 2 are running, possibly an audible alarm and temperature readout for inside the closet, in the wall and outside ambient air.

I may just have to do this.
 

Spartacus

Well-Known Member
May 27, 2019
773
316
63
Austin, TX
The T-stud looks interesting, I already bought my structural lumber for my project though.
It seems like its just 2x6 or 2x8 with a middle space for more insulation though I'd still have to either foam fill or blow-in fill it?
My personal plan is 2x6 with standard R19 batts, then 2" foam on the exterior instead of drywall for an extra 10R or so (its in my attic not garage though, so should be bug/pest free)
 

Layla

Game Engine Developer
Jun 21, 2016
149
90
28
37
Most servers can run fine in 45*C heat if you tell them to run in extended temperature mode, I wouldn't waste my time with HVAC at all, just buy equipment that can deal with the temperatures and keep them at ambient (with fans to circulate outdoor air to the space). Air filtration and humidity are then the more important things to control for in that scenario, which might be reasons to fallback to using a heat pump/AC. Also, if you want to do a UPS setup, I'd keep the batteries in a neighboring climate controlled room.