So I have this silly idea/longterm project of wanting to run a server on renewables on my farm. And I would like to reuse the heat generated by the server, for example to heat a grow room, or simply my house. How much heat does a server produce, and where would you consider it best applied? Has anyone built such a thing?
A server produces an amount of heat equivalent to it’s wattage.
A 500W server rack will produce 1/3rd the amount of heat as a 1500W space heater. If your rack draws 100W at idle, than that’s how much heat it produces. So if it’s cold outside you could spin up folding at home or some other thing to burn excess CPU cycles
As long as your server is inside your house it is offsetting the amount of heat your HVAC system needs to produce - granted it is also greatly increasing the amount of work your AC needs to do in the summer
There is a cricket farm in Quebec that heats it’s enclosures with Bitcoin mining rigs.
Servers are 100% efficient at heating, but heat pumps are 300% efficient. Get the most energy efficient devices you can, and heat your house with a proper heat pump.
You can even dump the cold air from the heat pumps into the server room and pull the hot air back into the heat pump again to gain even better efficiency
Well, that was my plan when I set things up with an air-to-hot-water heatpump in the same room as my homelab. But the reality is that when it is hot outside, I don’t need to run the heatpump (mainly because the solar-thermal water heater is so much more effective). And otherwise the there is no need for cooling in that room.
I do this. If you want to actually want to use or donate the processing power, this is kind of a good thing. However, there are a lot of downsides:
- Computers are generally much lower power than a heater. This makes them very slow to “react” to heating needs. Heating a small room, even with a 500W PC, could take an hour or maybe more.
- Heaters have a thermostat, which computers don’t, so even though they are very laggy, they also don’t stop heating when the temperature is right. This means they can overshoot and make the room uncomfortably hot.
- You could set up an external thermostat but then you need a load which can be switched on and off.
- I was using folding@home, but the work items take a long time, and switching them on and off will increase the time taken to resolve the work item, which in turn means the system could get annoyed and use someone else’s computer to resolve the work item faster, or worse, blacklist your computer.
- Using your PC to generate heat will use up its maximum lifetime. The fans aren’t built to be running at max speed all the time, the CPU & GPU could wear out, and the power systems will also wear as time goes on. You sort of have to align that lifetime against usage. This is likely fine if you see the computation as a donation or if you have important stuff to compute, but it’s probably not worth just wasting the cycles.
I would love to hear more about your setup and build. How are you using the heat, and what did you have to build to make use of it?
I’m just using it as a space heater for my study, which is also where I work from. While using the computer in Winter I just switch on f@h for both CPU and GPU (AMD 5700x and 6700xt), and this heats up the room. It’s a good 300-400W. I have home assistant telling me the temperature in the room and it bugs me to turn it off if it’s too hot. That’s my “temperature control”. I didn’t build anything, the computer is just under my desk and it heats up my room.
Originally my plan was to have F@H automatically turn on and off based on temperature, but it turns out the power is low enough and the lag is high enough that you switch it on in the morning, and then once the room is upto temperature you can just switch it off and the room will stay warm the rest of the day.
I can’t remember what youtuber did this. But some guy tried to heat a pool this way with their server rack
That was LTT https://youtu.be/wjO6OLmZB9A He admits that its a dumb idea on the wan show later so take that as you will. While i havent read the other comments yet, i bet at least a couple have recommended heatpumps. They are the best solution here.
But if you want to have some fun, grab a large pump and water cool the server, make sure all your water cooling connections can withstand the pressure your giving them and then run the cooling tubes out to your green house.
I run a quite powerful server rack for my business (two servers with 64 core Threadrippers, redundant power supplies, nice SSDs, etc) and it puts out some heat, but not even as much as my gaming PC. The CPUs are usually sitting near 2% utilization, so it’s barely drawing any wattage, and thus, barely putting out heat. So it really depends on how much the server is doing that will determine the heat it outputs. You can build a 1000 watt server, but if it’s only drawing 50 watts, it won’t be generating much heat.
That being said, if the alternative is an electric heater, then using a server for something productive like BOINC or Folding at Home is a better use of your electricity, and may produce the heat you’re looking for. And for your use case, an older (and thus cheaper) CPU would probably suit you, so win-win.
You could probably mod a water cooler system to connect to a water to water heat exchanger like this: https://www.heata.co/
In general, like others have said, lots of humidity is bad for the hardware, you will need to separate this somehow. But heating a small grow-room with an extension of a CPU water cooler might be possible.