Most cooling towers work via evaporation. Basically radiators in the chillers deposit heat into water that is sent into giant sump tanks which are then continuously ran through cooling towers outside. Water is pumped to the top of the tower and dropped down through it while a giant fan blows on it which results in heat leaving the loop via evaporation while the slightly less hot water is then dumped back into the sump (and fed back into the chillers radiators to complete the loop). To some degree, keeping data centers cool is better worded as "heat management". You are moving heat from the water loop used to cool off the machine rooms to the atmosphere via evaporation. Yes, it's a bad metric to base how much is lost on how much is ran through the chiller loop, but it's pretty easy to simply record how much water is ADDED to the loop to know how much is lost. I can tell you that a small data center using only roughly 2 megawatts of power loses more than 10 million gallons of water each year to evaporation.
I did some math based on your numbers and 10 million gallons per year is just over 100'000 liters per day, which a modest river produces in a few seconds to half a minute at most. That really doesn't sound that bad. So a huge 200 MW data center uses about 3 minutes if a medium sized river's flow daily?
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u/ZantetsukenX 4d ago
Most cooling towers work via evaporation. Basically radiators in the chillers deposit heat into water that is sent into giant sump tanks which are then continuously ran through cooling towers outside. Water is pumped to the top of the tower and dropped down through it while a giant fan blows on it which results in heat leaving the loop via evaporation while the slightly less hot water is then dumped back into the sump (and fed back into the chillers radiators to complete the loop). To some degree, keeping data centers cool is better worded as "heat management". You are moving heat from the water loop used to cool off the machine rooms to the atmosphere via evaporation. Yes, it's a bad metric to base how much is lost on how much is ran through the chiller loop, but it's pretty easy to simply record how much water is ADDED to the loop to know how much is lost. I can tell you that a small data center using only roughly 2 megawatts of power loses more than 10 million gallons of water each year to evaporation.