TIL "district heating" (a heat distribution system) is a thing. It does make sense to use waste heat from industrial processes to heat homes.<p>I'm not a thermodynamics expert, but I think you probably need some density of heat sinks so it only really works in cities.<p>I wonder if in the summer, it could work in reverse? I speculate there are two options for summer operation: (a) a centralized AC plant sends cold fluid into the pipes, or (b) a decentralized AC heats hot fluid.<p>With option (a) I suppose it's not very backward compatible with a heat-only system, if you have a bunch of customers who built their factory expecting "this pipe will always be hot" they might have a bad time if you make it cold half the year. With option (b) it's more backward compatible but I think customers might not like it. I'm pretty sure AC gets less efficient based on temperature gradient so pumping AC into a heat transportation pipe would be more expensive for customers (electricity, wear-and tear on AC, takes longer to get to the commanded temperature when you reduce the set-point). So you'd have an incentive to unhook your AC from the system and just send heat into the air instead.
The article seems a bit obsessed with the size of individual units.<p>Latest generation district heating systems distribute the heat pumps around the system for greater efficiency.<p>Big units might be the simple option for upgrading older systems from fossil fuels but they can probably do better with a little planning.
A couple of figures that seem sorely missing from this article: what's the COP (coefficient of performance) of these heat pumps? And they talk of some temperature rise, but what's the temperature drop in the water they're going to dump back into the sea or into the river?<p>Without these it's impossible to understand the environmental viability of these projects when compared to fossil fuels.<p>So are these a significant improvement or just PR pieces for the suppliers? Give us the figures!
I'm curious about the environmental effects of harvesting heat from the environment. Given that hurricanes are driven by extreme sea surface energy, it would stand to reason that harvesting enormous amounts of excess energy in natural systems across a large enough area would be useful. Harvesting in too localized of an area could cause ecological problems.
The main advantage of these systems is that they can be used for cooling too.<p>The main disadvantages are that they require enormous amounts of co-ordination socially and you pretty much have to run the 24/7 (and then store heat which is wasteful). You also need a heat source (normally a large body of water) nearby.
>In this installation, the heat pumps' CO2 refrigerant will absorb a small amount of heat from seawater. Compressors boost the temperature of the CO2 and the system can then transfer this heat,<p>accurate reporting , as ever , from the BBC