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Dragonfly_Select t1_iu1ck2j wrote

Reply to comment by flannelmaster9 in The inside of an Electric Vehicle Charger. by rcmaehl

The form that electric heating is going to take is likely to be different than what most people expect. Straight electric heating isn’t going to play a big role. Most of it will be air or geothermal heat pumps.

An air heat pump is just a slightly modified central air system. In an air heat pump the AC unit can run “backwards” as well as forwards. In the backward configuration, the “hot side” is placed inside and the “cold side” outside. This turns out to be really cheap and effective down to about -20F (-28C). That covers most of the population.

For colder climates the trick is to conceptually bury the cold side of the heat pump below the frost line. In practice this is done by burying a recirculating water line beneath the back yard. The cost here is on par with installing or replacing a septic system.

The nice thing is both of these solutions are very efficient and cost comparatively little to operate. Swapping a house in NY from oil and a normal central AC to geothermal cuts annual heating and cooling costs in half. Throw in the tax incentives going into effect in the US next year and the whole thing pays for itself in just a few years.

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flannelmaster9 t1_iu1dqf7 wrote

That's all done with a reversing valve for mini splits. I know geothermal exists but have only seen it in rural areas. I don't have enough space in my yard to trench up for the loops. I also live in a region that can be sub zero for a few weeks. -20 is probably the coldest I've seen minus windchill. I've only seen one oil burner in the wild and it threw me off being in the middle of a metro area I've serviced for years.

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Dragonfly_Select t1_iu1xuel wrote

Yeah, cold urban areas are going to be a bigger challenge. Someone in my old neighbor did drilled geothermal. It doesn’t take much space but you need a ground scan to make sure there isn’t anything problematic in the way.

For cities there is talk of effectively reviving steam heat loop systems except this time built around heat pumps. Basically using the existing natural gas right of ways to provide room temperature recirculating water from a centralized source. Denmark is experimenting doing this with waste heat from data centers and other industrial processes.

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flannelmaster9 t1_iu1yhlc wrote

Detroit steam works still heats numerous buildings downtown, I doubt it's effective as Denmark.

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Mungologist t1_iu200kz wrote

It's done via reversing valve for all heat pumps.

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Mungologist t1_iu1zykg wrote

You arent running a heat pump below 35 degrees Fahrenheit reliably dude lmao. You're going to be cooling your house via defrost for 70% of its operation. If you're using the heat pump as the auxiliary to a gas furnace maybe, but that's useless in 90% of climates.

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