I am currently struggling w/ the exact same dilemma.. I live in Georgia, where we have HOT summers, sometimes mid-to-high 90's.
Here is my current idea.. I have ordered a rack-mount setup for my 2 S9's that are on the way, but instead of just mounting these in a traditional server rack enclosure w/ side panels, doors, etc.. I'm going to mount in a rack frame (
https://www.amazon.com/StarTech-com-Adjustable-Server-Cabinet-4POSTRACK42/dp/B00HVKOPBW/ref=sr_1_8?ie=UTF8&qid=1512998380&sr=8-8&keywords=Server+Rack)
Once I get that done, I am going to build a box enclosure from regular wood from the Home Depot
Plan on cutting at least a 10 to 12" hole in the top for exhaust to evacuate, duct it with 8-12" duct piping from the top of the enclosure, along the top of the garage, and pipe it to exhaust through one of our decorate vents on the front of our home.. This way, no additional holes have to be cut in the house, I can simply vent through an existing vent. To assist with the exhausting, i'm going to add in a vortex fan inline (
https://www.amazon.com/Atmosphere-S-1000-Vortex-S-Line-Ultra/dp/B071FGNR5Y/ref=sr_1_3?ie=UTF8&qid=1512998563&sr=8-3&keywords=Vortex+S)
This should move enough hot air out of the enclosure to keep things relatively cool. Another reason I want to build this box is to make sure all air entering has been filtered to avoid clogging of the heatsinks since this will sit in the garage. So, I plan on cutting 2 traditional home air filter holes in both sides of this unit at the bottom, so air can be sucked through naturally, and filtered.
And finally, due to hot summers, my plan is to cut 2 ports into the box, also at the very bottom, and add at least 1 (if not 2, depending on if the demand is there when summer rolls around) of this floor AC units (
https://www.amazon.com/Tripp-Lite-SRCOOL12K-Portable-Conditioner/dp/B002XITVCK/ref=sr_1_2?ie=UTF8&qid=1512998708&sr=8-2&keywords=Server+Rack+AC) or, alternatively, one of these at the bottom of the rack flush mounted on the front of the cabinet (
https://www.newegg.com/Product/Product.aspx?Item=N82E16816228178&ignorebbr=1&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Server+-+Accessories-_-N82E16816228178&gclid=CjwKCAiA9rjRBRAeEiwA2SV4ZWOkcto58CA2y6u2g5gcI0Ufw3l65lHWQwPtOxYUk3rVgzuMe7tbBBoClvkQAvD_BwE&gclsrc=aw.ds)
For the A/C units, their exhaust hot air can also be ducted into my exit tubing with T connections, so the ambient temp of the garage shouldn't be increasing due to proper routing of hot exhaust gases straight out of the front of our house.. With the AC pumping directly inside the cabinet, although it will be sucked quite quickly, I would imagine that would help keep the temps down where they need to be down (i.e., ONLY inside the box instead of trying to cool the entire garage, which would be a losing cause)..
Lastly, another reason to build the box enclosure is for sound dampening.. I plan on lining the box with dynamet or some other sort of noise suppressor that is heat resistant so the garage doesn't sound like an airport
The reason i'm considering doing this is I plan on scaling this from the two S9's I have on order, to several rigs.. I also have a 6 GPU setup right now for Ethereum that I may change over to a rack-mount chassis and stick in there. Would be a good place for any servers down the line, etc..
Thoughts on the efficiency of the design?
*Only other potential option is scrap all that and colocate these, but with only 2, it isn't cost effective.. would have to wait until I scaled to 6-10 of them.
Thanks in advance,
Matt