From what we have learned from mining bitcoin back in 2013 to mining ethereum now is that the GPU's that mine Ethereum produce a lot less heat then the SHA256 equipment we used for bitcoin but we have an open rig design to allow air flow to take away heat.
Also, the rigs are located in the mountain area east of Albuquerque thus it is cooler then here in the city. It is about 1000 feet higher in elevation (almost 7000 feet) then the city. I don't know if this helps but i am going to ask my friend more about this.
I do love solar since it helps to nullify the electricity costs if planned around. My previous job i designed solar systems for homes and businesses thus know how to calculate how much solar is needed to cover any electric usage (i designed my own system on my house).