I have always thought of heat pumps as behaving like the the Leaf's heating system - great when it is only cool, but much less effective when it is actually cold, with COP dropping to near 1 by -15°C. Then today I learn about systems using CO2 as a refrigerant that maintain a COP over 2 down to -30°C. That could actually work in places that get real winter. COP still depends on delta-T though, and the combination of falling COP and increasing heating demand leading to dramatic increases in power demand as temperatures drop might be difficult for electrical grids to accommodate.SageBrush wrote: ↑Fri Nov 01, 2019 10:16 amEver heard of heat pumps ? One would only need a winter season COP of ~ 1.5 to match combusting NG, and that presumes that the heat pumps are used in the same lousy distribution system as the NG. In reality they are used as mini-splits and the 20-30% losses of distribution are avoided.Titanium48 wrote: ↑Fri Nov 01, 2019 10:04 amThat only works if you have a reliable supply of non-fossil electricity. Otherwise, it is more efficient to burn natural gas where you need heat rather than in a powerplant with 60% efficiency at best.Zythryn wrote: ↑Fri Nov 01, 2019 9:36 amThis is about the first (of many hopefully) city to ban natural gas.
I applaud them for this step.
Here in Minnesota, Natural Gas is almost a given at any house. We specifically built without it for a number of reasons, including energy efficiency, cost, and health.
That brings up the other option for more efficient use of natural gas - cogeneration. Instead of just burning gas to heat your house, use it to run a generator and heat your house with the waste heat. The two options could be complementary during the transition, with lower temperatures resulting in more power production from buildings with cogen units, while buildings with heat pumps increase their consumption. Cogeneration would also be complementary to solar PV, as heating demand is inversely correlated to solar PV production.