I love what you did with server racks. I mean it does impact cooling performance a bit but for the big time miner much more efficient to manage a shit load of rigs and direct heat where you want.
No, it doesn't impact cooling. Think wind tunnel, the hot air won't get stuck in a wind tunnel vs stale air in open air rig if you don't have box fans. Plus open air rigs, recirculate the hot air over and over. Box fans just keep moving the same hot air. My design does not. It takes in cool air and blow out the hot air. The better the seal / vacuum the more efficient it is. Before all I invested this large amount of money, I did a lot of heat stress testing on both designs within my heat wall including different fan configurations. I feed both open air rig and server case rig with recirculated 115F heat. Which one do you think did better? Most would guess open air but it's not.
In this same oven, is where I bake all my new rigs for at least 24hrs before I send it to it's final location. The reason for that is, if it's going to fail, it will fail even faster at hotter temp.
This is also where I touch and "feel" all the SATA to MOLEX cables. They looks like the same AWG thickness but some vendors uses very CHEAP cables that will burn down your rigs. If the cable feel burning hot, those are the ones that will melt later or cause small fires. Not a cheap plug, but this is why I only buy from trusted vendors who are also miners themselves such as Hawkfish007. No riser batch will be perfect but he at least do sample testing and stands by his product so any issues, he takes care of it for me fast.
My garage intake ambient temp should never reach 115F as the hot air is not recirculated. I haven't had the need for intake fans (all via negative pressures) yet so I am able to avoid box fans. I try to keep things minimalist as possible. I currently have over 40 rigs or close to 280 GPUs (Not all are 7 gpu configs) running in the garage. In a similar setup like this, typically you would see at least 4 x 7200 Exhaust fan for the volume size, some intake fans, maybe 1 or 2 Swamp cooler and many many box fans while still not able to keep the temp down. Just imagine how much wattage, noise and cost that is to buy and maintain each month if I need that much gear! Efficiency to me is SEXY but lowest operation cost / maintenance is SEXIEST.
P.S I made some edits to remove the wording of UGLY box fans as I know we all have them (I still use in my shed for Exhaust), so it may offend many............... haha