Recycling the heat from server room

Dreece

int 21h
Been toying with the idea for a while, think I'm just going to go for it as it makes sense, just wondering if anyone else here is into recycling energy... in this case heat.

The plan is to plumb one of these in with the appropriate fans and ducts, planning on using foil backed insulation to shape a nice duct off the whole back of the server rack with rubber seals along the perimeter as a mating flange.

 

T_Minus

Build. Break. Fix. Repeat
Feb 15, 2015
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When I was building the second 'server room' in my home office I had it designed with 22U racks with air in front hot air into back, with a vent to my office that could be opened\closed, and then the other vent outdoors. Window\Wall AC to create cool air, and hot air in summer went outside, in winter could go into my office.

I purchased all the material, insulation, door, racks, etc then just expanded my data center off-site and didn't finish ;) but that was the ultimate goal. Free heat for winter.
 

omegadraconis

New Member
Oct 23, 2017
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You just need to put your Datacenter next to a heatpump water heater. Might get some recovery from that, but would only be worth while if you had a need to replace your existing water heater.
 
Apr 9, 2020
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One of the concepts I didn't see discussed on here was the idea of building a heat reservoir to store and redistribute heat. While its very difficult to generate electricity from waste server heat and fairly hard to find something to do with all that hot air, there are a lot of good potential uses for some warm water.

Simplest idea: if you have a swimming pool, build a heat exchanger in the server room. Nothing fancy, you don't have to pile pool water into every chassis; just an old car radiator with a couple of good fans will do. Place the radiator in the room with the servers and pump water from the pool through it. This will remove heat from the server room and deposit it in the swimming pool, which even if you live someplace warm could probably benefit by being heated up a little. One radiator might not actually do the trick - I haven't got a pool to test this myself - but it does seem like it would work in principle.

Slightly more complex: Build a revivor out of a plastic cistern or a couple 50 gallon water barrels. Same concept: use a radiator in the server room to deposit heat in the water, then use other radiators elsewhere to discharge it later. You could, for example, set one up outside to run at night when its cooler to chill the water back down. Or set it up in the house to warm the house. Alternatively(and this is much harder) figure out the physics of using it to maintain constant temperature in the server room. By day it soaks up heat, by night it returns it. I have been wrong before, but my understanding is that constant temperatures are better than temperature swings, if you aren't able to maintain a constant low temperature its better to be slightly warm all the time than warm/cold/warm/cold.
 

psc

New Member
Jun 30, 2019
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I think to be effective, you'd want an air\water heat pump (effectively a water-cooled air con unit). Otherwise the room temperature would need to be quite high before you'd get a meaningful heat flow into "room-temperature" water. The only calculations I can find for a car radiator do look good, but assume flow rates for both water and air that you just wouldn't achieve (or want to) in a server room - never mind the operating temperature differentials!
 

acquacow

Well-Known Member
Feb 15, 2017
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It would be more efficient to capture hot shower water and pump that heat back into the house.
Capture greywater from showers/dishwasher into a small cistern, submerge a radiator or two into it and locate a remote radiator inside your home HVAC ducting to deposit that heat back into the home.

Once the cistern drops to near-ambient, you simply drain it back out.
 
Apr 9, 2020
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It would be more efficient to capture hot shower water and pump that heat back into the house.
That would kind of defeat the purpose of recycling heat from the SERVER room, no? :p

I think to be effective, you'd want an air\water heat pump (effectively a water-cooled air con unit). Otherwise the room temperature would need to be quite high before you'd get a meaningful heat flow into "room-temperature" water. The only calculations I can find for a car radiator do look good, but assume flow rates for both water and air that you just wouldn't achieve (or want to) in a server room - never mind the operating temperature differentials!
I would think you could get a better effect using more radiators, right? Instead of just 1 use 6. I dunno. Like I said, haven't got a dedicated server room to experiment with. Also you could theoretically cool the water down well bellow daytime room temperature at night, assuming you just want a heat pump and don't want to try to do anything with the heat. I guess the whole point is using water to absorb it might provide more option than just trying to duct hot air around.
 

acquacow

Well-Known Member
Feb 15, 2017
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That would kind of defeat the purpose of recycling heat from the SERVER room, no? :p
Air to air heat exchangers are pretty inefficient. You'd be better off just adding a supplementary vent system from the server room into the HVAC directly.