Comment by matt-p
21 hours ago
(DTC) Datacentres take electricity and turn it into low grade heat e.g 60c water. Put them anywhere where you've either got excess (cheap) energy or where you can use the heat. Either is fine, both is great, but neither is both bad and current standard practice.
It's perfectly possible to put small data centres in city centres and pipe the heat around town, they take up very very little space and if you're consuming the heat, you don't need the noisy cooling towers (Ok maybe a little in summer).
Similarly if you stick your datacentre right next to a big nuclear power plant, nobody is even going to notice let alone care.
Well a few considerations:
- You have to size your cooling towers for your hottest hour. Doing this saves you no capital costs.
- You barely have to run the fans on your cooling towers in the winter because the air is so cold. So often this also won’t save you much operating costs.
- Already there is an essentially unlimited amount of so called “waste heat” from power plants and factories. Building district heating systems is extremely capital intensive, which is why this isn’t done more.
- As a municipality it’s just a horrible idea to make the heating system of your whole city rely on a random company continuing to operate (even worse if said company is in a potential bubble). This is why most district heating systems work with power plants - they already have the government involved in ensuring their continuing operations.
I don't think I ever said it reduced capital cost. I agree (though you might be willing to take more risk on reducing redundancy e.g instead of 2+1 cooling towers you may be more willing to just buy 2).
You cannot put a power station in the middle of a city centre, you can put a datacentre there. The main reason this isn't done more is that it's expensive to build heat network between the 'far out of town industrial area' where they put the heat sources and the city centre where the heat consumers are.
I don't know why a municipality is involved, but regardless you can simply install a backup heat source and/or add a mix of heat suppliers to the network. Backup gas boiler or similar is not that problematic or expensive to add particularly because you don't need to add redundancy as it's just there for a backup scenario.
Resistive heating is a tremendously inefficient way to generate heat. Sometimes it's worth it if you get something useful in exchange (such as full spectrum light in the winter). But it's not all upsides.
Heat pumps are magic. They're something like 300% efficient. Each watt generates 3 watts of useful heat.
I share your enthusiasm about heat pumps, but I wonder what the efficiency of using waste heat is. Couldn't it be competitive with heat pumps? As it's a waste product, isn't it reasonable to also expect it to be more than 100% efficient?
As a rule of thumb (obviously it varies) you spend about 1% pumping water round a heat network. So your CoP is around 99 if you consider heat truly free. It's actually higher as pump energy largely is converted to friction/heat.
You can’t extract energy from heat by itself. Only from a heat delta.
Think of heat like flowing water or charge. Only an altitude or voltage delta creates the flow needed to harvest energy.
You get no useful energy from heat you are already trying to shed because you have no delta to work with. (The entire problem exists because there is no surrounding environment with high heat capacity and lower heat.)
3 replies →
Much more than 100% since the only energy you need to put in is for pumping the hot water around.
Its not inefficient if you were creating the heat anyway, its a completely free byproduct.
Yeah. This. Obviously if the objective is just to generate heat only buy a heat pump and not a B200!