yes

vent  >>>>>>>>  gear >>>>>> exhaust fan >>>>>>

can work  but many details are needed.
4 rigs   could be 6 nvidia 1080 ti cards per rig  or close to 4500 watts
the no fan vent could be too small.
the  fanned exhaust vent needs to be strong
we have two of these
http://www.homedepot.com/p/Master-Flow-1600-CFM-Power-Gable-Mount-Attic-Fan-EGV6/205924917

in the solar array  we have 9kwatts of mixed gear




I put this tarp in today closer to the roof it dropped temps a lot

https://www.amazon.com/gp/product/B000NQ16PE/ref=oh_aui_detailpage_o00_s00?

putting this in next week

https://www.amazon.com/Double-Bubble-Foil-Insulation-125/dp/B017YCYT5S/ref=sr_1_fkmr1_4?


and this is in now
https://www.amazon.com/Car-Insulation-Deadener-Automotive-Lightweight/dp/B016QURU1Y/ref=sr_1_27?




goal is to make a tunnel for wind to flow the heat out the exhaust.

the tarp is on top  it shades  the loft and reflects heat.

the silver bubble is not in yet   it will be second

the car insulation is in and goes around the gear racks fully.  it is a heat shield it is fire proof as it is used on car engines  to reduce sound and stop heat from reaching the driver


      __________________TarP________________
      -------------------------Bubble--------------------
                         @@@car insulation@@@
                         @                               @
                         @ Gear Racks  -.. @
                         @                               @
                         @@@car insulation@@@
___________________loft's floor_________________

3 layers to keep summer heat out. We had heat issues last summer.