Topic: Harvesting waste heat from GPU rigs? (Read 1072 times)

 It can actually be MORE cost efficient, depending on your relative rates for electric vs gas and the efficiency of your furnace - and it's almost always MORE cost effective vs. an oil burning furnace.

 As far as the summer - you COULD run a water-cooling loop, and put the input for your hot water heater at the "hot side" of the loop and tap into your cold-water line at the cold side of the loop (or use a heat exchange setup at the input of your hot water heater), but you can pretty much count on the vast majority of the heat your rigs generate going to waste one way or another.

redirect it with a radiators and a tube? i see some peopel using this method to exhaust the hot air outside of the room where there are the rigs working, not sure how much you would lose in this way but it's worth a try

IMO, the best thing would be to have a duct system in the house that pumps the hot air and sends it in the rooms during winter time, which means you'd have planned your house for this before starting your mining operation. Sort of like that Canadian heat system where you put a duct underground that heats/cools the air naturally (puis canadien I think it's called?).

Warming water with the rigs just sounds like a really cumbersome idea. It's not a bad idea in itself, but it just sounds like a huge hassle. Just the price of the watercooling equipment for 6 GPUs...and then when you need to troubleshoot your rig and have to remove a GPU...it's going to take you an hour to make sure you're not spilling water everywhere...which also makes it quite dangerous.

I wouldn't mess around with water on my rigs, just sounds like a terrible idea.

I only move them in the winter because of practicality - the GPUs are air cooled by default, so they get the job done of heating the air in the house without any exotic setup. My house heating is steam radiators, which just heat up water anyway, so if it's practical to preheat the water feeding into the boiler then there's no need to move the rigs.

I know how PC watercooling works, but I don't know anything about the specifics necessary to feed that heat into the boiler. The expense of the waterblocks themselves might make this impractical so I was hoping to find a way to achieve at least some recovery without going down that rabbit hole. But if GPU watercooling is necessary, can you recommend any specifics as far as the heat exchanger goes?

Although new, i have been thinking a lot on this as well.

Heat exchangers are widely used in the petro-chemical industry, and by design, they keep the cooling/heat medium separate from the process lines for obvious reasons. In your case that would be two loops.

The incoming cold water to the holding tank/exchanger would need to go trough several passes in order to absorb sufficient heat and then exit to the cold (and now warm) side of the water heater. The water cooled GPUs would need to do the same thing, but on a different loop. One loop would be the tank, and the other would be through tubes. I dunno of the top of my head which one that should be, but in theory it should be good. Talk to a good Chemical Engineer...

The concern is that you want to relocate the rigs in the summer and winter. I would think you would want a permanent setup out in the garage, but that might not be needed depending on the amount of of heat you can feed into the exchanger. So, you would need quick disconnects for your GPU blocks that would then get disconnected from the exchanger loop and subsequently connected to standard 140/280 radiators with fans that are permanently mounted to your rigs.

And, you would need several disconnects on the exchanger's second loop (1 in, 1 out for each rig or set of GPUs) for use during the summer, and 1/2 huge radiators on the rigs (also dependent on the number of GPUs).

So, each rig would also need 1 or 2 dedicated pumps to circulate enough water depending on a lot of temps. The optimal solution would require some calcs, but is doable.


Loop 1: Water source-----> holding tank-----> hot water tank.
Loop 2 rig 1: Tubes from exchanger/tank----->Small tank on rig----->pump on rig---->GPU0---->GPU1---->GPU2---->GPU3---->Tubes to tank
Optional depending on the temps from last GPU on the rig
Loop 3 rig 1: Tubes from exchanger/tank----->Small tank on rig----->pump on rig---->GPU4---->GPU5---->GPU6---->Tubes to tank

Here is a link http://www.pcgamer.com/a-beginners-guide-to-liquid-cooling/

How to get the heat from the GPUs into the tank though?

Do you have a hot water tank?

If you do you can install a holding tank.

Water source----- holding tank----- hot water tank.

This is common setup in areas of the world that have very cold water source.

So if you put in a holding tank it will lower your hot water heating
.

you can just put in a tank a 50 to 100 gallons.  Of course it needs room.

Now that summertime is rolling around, I'm starting to think of more creative ways to utilize the waste heat coming off of my mining rigs.

In the winter this is easy. Rather than building a large centralized mining operation in a garage, shed or basement, I distributed the GPUs into smaller microATX builds with 2 GPUs each. There's more overhead in terms of the support parts needed to run this such as CPUs, cases, motherboards, etc. But by strategically placing them throughout the house, 100% of the exhaust heat gets put to good use by heating the air, which directly reduces the burden on my traditional HVAC. Of course the electric heat isn't as cost efficient as burning oil/gas, but it's still a big win.

Of course in the summer this flips on its head and would increase the need for AC, so all of the rigs get consolidated into my basement and laundry room. And it occurs to me that in those two rooms there's a lot of things that could put the heat to good use, if only there was an effective way to harvest it. I've googled around but there surprisingly isn't much talk about this, especially considering how much potential extra profit there is here.

The first and most obvious target for is to convert that waste heat into hot water. Obviously by itself they can't heat water to a high enough temperature on its own, but it could be used to preheat water to ~80C before the boiler takes over from there. So what are some realistic options to do that? The most direct way would be watercooling the GPUs and using the water in the loop directly, but then I'd need to loop the GPUs directly into tap water and that's a bad idea in multiple ways. I've read of using some sort of heat exchanger to keep the loop separate, but now that's adding cost and complexity to the point where it stops making sense.

Ideally I'd like not to have to modify the hardware *in* the rigs, and concentrate/harvest the hot air coming out of them. They could be vented into a small space using fairly simple ductwork. If you could get most of the hot air into a small space, wouldn't it be possible to use some sort of heat pump/exchanger to transfer that concentrated  thermal energy into a boiler preheat tank? Surely I can't be the only person who's thought of this.

A simpler but less broadly useful application would be to make that space into a pseudo-clothesdryer, but that seems like more of a neat trick than anything else.

So what's the state of the art when it comes to recycling the waste heat year round? Is there a practical way to do this or have people just given up on the idea?