running mining rigs makes the air in my mining room drier than the rest of the house, the water i spilled on the floor evaporated quickly, it is quicker to dry clothes in my mining room compared in drying them outside, and a portion of the room becomes cooler when clothes are being dried. I defrost stake in more or less 5 mins ...those observations for me makes me think that swamp cooling here is feasible..i may enjoy the cooler climate now but i know what summer will bring to my mining room
i have no way of measuring humidity here but based from my observations above, a constant pump of water to the cooling pads or columns of towels(custom made ) and a fan would make a difference here.
i haven't researched more about humidity but i think humidity or water in the air helps GPUs to transfer more heat to the air just like how water in the radiator helps transfer heat from the car engine to the radiator..
Humidity level of the air as such has insignificant effect on heat transfer from a heatsink to air.
Your mining room "gets drier" because air can hold more moisture as it gets warmer, so the "relative humidity" drops even if the actual amount of moisture in the air per CC stays the same.
drying clothes acts as an impromptu evaporative cooler.
What area are you in?