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How a heat pump works

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Re: How a heat pump works

#111

Post by nashashmi »

gabrielhidasy wrote: post #65
nashashmi wrote: post #16

Earlier quoted context omitted.

They are not more energy efficient than burning gas. Edit: since i am getting downvoted to oblivion, let me fight back here. I genuinely wished heat pumps would be more efficient and in theory they can be. I would love to not generate heat and just use the outside heat energy and compress it down into a smaller location. But compressing and decompressing is not an energy efficient task. It takes a lot of work. Mechan…

They literally are more efficient than burning gas, a good heat pump can do over 300% efficiency (KWs of heat in your house vs KWs of electricity used) while a furnace can only hope to get 100%. Even if the heat pump is fed from gas power plants (which burn gas with about 50-60% efficiency, more if the waste heat is reused), they are still using less gas for the same amount of heat than directly burning it.

400% efficiency? Is that even possible? (Did AI write this?)

Re: How a heat pump works

#112

Post by snuxoll »

mhb wrote: post #8
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

That and gas stoves bad.

The whole bit about gas stoves I have no doubt is a pretty typical astroturf campaign from the fossil fuel industry. They have shamelessly made up pro-gas nonprofits using fake personas, paid social media influencers to promote gas stovetops, and are likely behind the current "gubmit wants to take away your gas stove" trend that's drumming up online drama.

One doesn't even need to look at climate impact to say gas stoves are bad, but focus the narrative on that one aspect and you can get climate deniers hyperventilating and defending their gas stovetop with statements like "you'll pry my gas stove from my dead hands". But really, economics are going to kill them all the same - induction stoves are dramatically more energy efficient, have the same benefits of fast thermal response, and don't pose a gigantic risk to life and limb every time you turn them on (or leave them off, for that matter).

Re: How a heat pump works

#113

Post by nashashmi »

pjerem wrote: post #50
nashashmi wrote: post #16

Earlier quoted context omitted.

They are not more energy efficient than burning gas. Edit: since i am getting downvoted to oblivion, let me fight back here. I genuinely wished heat pumps would be more efficient and in theory they can be. I would love to not generate heat and just use the outside heat energy and compress it down into a smaller location. But compressing and decompressing is not an energy efficient task. It takes a lot of work. Mechan…

Yes they are. You get more heating from an heat pump running from electricity coming from gas plants than what you get by just burning the gas. Including losses on the grid.

I cannot imagine this in anyway. Heat pumps work like ACs do. They do compress a medium till it heats up, and then spread that heat around. And then they decompress until it cools down and dump that cold until outside heat brings up the temperature again.

Those compressions and decompressions take up immense amounts of energy. They are less efficient than simply burning gas. On the flip side, could we not create electricity generation and heating from Natural gas?

Re: How a heat pump works

#115

Post by kavalg »

boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

I am a happy user of a DYI air source heat pump, that I've been using for 8+ years, mostly for heating in a residential building.

First, it must be told that an off the shelf AC unit is technically speaking also a heat pump. There has been this distinction (and confusion) between AC units and (mostly) ground source heat pumps because, you know the latter actually have a water 'pump' to circulate fluid in the ground piping. Ground source heat pumps are far more expensive that AC units and are nearly impossible to retrofit in existing buildings. Hence, companies came up with a 'middle ground' solution, called air source heat pumps. In these devices the outdoor unit is much like an outdoor unit of a split type AC, but the indoor unit is basically a refrigerant/water heat exchanger with a water pump and some sensors around it. There is also a monoblock type of air source heat pump, where all components are in the outer block and you only connect the piping.

IMHO, the reason air source heat pumps are becoming popular now is because their price went down considerably during the last 5 years, whereas the price of fossil fuel heat sources has gone up. Back then when I had to choose between a gas boiler and a heat pump, the boiler was around EUR 2, off the shelf heat pump (24000 btu) was around EUR 7k and for the DIY option I paid a total of EUR 2.3k. The reason for this was that the market for air source heat pumps was underdeveloped and companies (e.g. Mitsubishi, Daikin, Fujitsu) were charging a lot more in this market segment (rich people with new houses). At some point in time, people started realizing the benefits of a heat pump over a normal AC (less units, no noise, nor air currents, better efficiency, can produce hot water, heating is decoupled from the source and more sources, such as solar can be seamlessly plugged in). Manufacturers albeit slowly responded to this demand.

Now with solar power gaining more traction, they are becoming a very obvious choice.

Re: How a heat pump works

#116

Post by endisneigh »

bilsbie wrote: post #110
endisneigh wrote: post #105

Earlier quoted context omitted.

A portable machine to provide heat and cooling via heat pump technology. For cooling this exists in many forms: there are the window air conditioners, and "portable" window air conditioners which have a duct that connects to the window. The problem with the latter is that they're loud and the ducts result in a lot of heat loss. For heating there are some portable air conditioners that use a heat pump but they're subj…

Cool idea. So a two piece portable with a just coolant line going through the window to the outdoor part?

yeah, exactly. there's a company called MRCOOL that does something similar (https://mrcool.com/diy-4th-generation/), but the head (the indoor part that provides the heat/cooling) is designed to be mounted permanently

if this were popular you'd see old houses retrofitted with pluggable holes where you could feed the lineset through and seal as necessary for temporary heat/cooling, or perhaps even permanent.

the installation would be substantially easier if these were like 6000BTU instead of minimum 12000BTU per head, so it could be run on say, ~8 amps and be plugged inside.

Re: How a heat pump works

#117

Post by elil17 »

boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

Well of course it is being pushed, though I would not necessarily call it coordinated.

Companies that sell heat pumps are advertising hard. It's an easy sell for them with rising gas prices.

The US government is "pushing them" by offering tax credits for heat pump systems. This is part of a plan to reduce pollution, improve energy independence/energy security, and save citizens money on their heating bills. No secret there - politicians and public servants are excited about this and they are talking about it. They are also offering tax credits for other high efficiency heating systems, but not that many people are looking at those tax credits because buying a new high efficiency gas furnace doesn't make that much sense when you could buy a more efficient heat pump instead.

Many individual people are also talking about them because they are a great way to help the environment and save money at the same time.

And I think a lot of people just think they are cool technology as well.

Re: How a heat pump works

#118

Post by prottog »

asow92 wrote: post #73
prottog wrote: post #57

Earlier quoted context omitted.

In the Northeast with that much square footage, you would be better off with ground-source heat pumps (whether open or closed loop), rather than the normal air-source heat pumps.

I guess the concern I have with all this is that my current system works well, and I don't want to spend $10K+ unless it brings down my heating costs significantly. Could a ground-source heat pump system do that?

Like other commenters said, a GSHP will work excellently in terms of keeping you comfortable at a low ongoing price, but your initial costs will far exceed a $10k budget and you will likely never make that investment back ;-)

Re: How a heat pump works

#119

Post by nicoburns »

vintermann wrote: post #38
nicoburns wrote: post #9

Earlier quoted context omitted.

> Is there a global push to get everyone to switch to heat pumps. I mean, yes. They're much more energy efficient than the alternatives and will play a key part of removing our dependence on fossil fuels. > I understand that its for climate benefits but it feels very coordinated. That seems like a good thing?

Yeah. If some people came together at Davos or whatever and decided "we need to promote heat pumps!", you can be sure they would mess it up. Consent can maybe be manufactured. Enthusiasm is organic, for good and bad.

Agreed that top-down programs aren't always very effective (although sometimes they can be), but would point out that "coordinated" doesn't imply top-down. It could just mean that lots of individual entities are working with each other to achieve a common goal.

Re: How a heat pump works

#120

Post by snuxoll »

sbradford26 wrote: post #93
asow92 wrote: post #73

Earlier quoted context omitted.

I guess the concern I have with all this is that my current system works well, and I don't want to spend $10K+ unless it brings down my heating costs significantly. Could a ground-source heat pump system do that?

Ground source/geothermal would significantly reduce your heating costs but it would be significantly more than 10k. For that large of house something like 40k+ wouldn't be out of the question, with the largest expense being drilling. I personally think geothermal is great, sadly New England's geography makes getting a ground loop installed more difficult. In the midwest lots of people would do a horizontal loop by tr…

My brother-in-law lives in NE and has installed mini-splits and has overall enjoyed them. A ground source system would be "the best" for that region, but if you're not doing a new build then air source works just fine there with the correct equipment.
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