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What is the real story around heat pumps?

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tom66:

--- Quote from: Siwastaja on February 24, 2024, 09:31:32 am ---
--- Quote from: pcprogrammer on February 24, 2024, 09:03:32 am ---The whole idea of these systems to pay for themselves is kind of bullshit. Sure it can reduce on your energy bill, but it will still cost money. Depending on the type of system and the cost to install it can take a long time before any savings start to come.

--- End quote ---

Remember that expensive systems such as quoted for you are a kind of specialty of wealthy societies and wealthy households. Energy solutions are being sold exceeding their true value, because there is market for that and people still buy. My air-to-water heat pump installation was less than 4000EUR all parts included, although I did the install work myself but it would have been less than 1000EUR for work if I just paid for hourly rates for electrician and plumber; and the end result is way better than how a typical 15000EUR complete one size fits all solution would have been.

Typical cost for air-to-water retrofit was around 8000-9000 EUR here but nearly doubled to 14-15000 EUR almost overnight after a 4000EUR subsidy come into place. The market does not reflect actual costs, and any subsidies further twist the market. Enough people are willing to pay outrageous prices when they feel good about it.

In Japan air-to-air heatpump costs something like 500EUR installed so one can easily afford one per each room. They do pay back for themselves, that's literally why they were developed in 1980's in the first place, to save cost of fossil fuels.

--- End quote ---

Indeed.  It is kind of bonkers how expensive heat pumps are to install professionally.  I can buy a monobloc unit for my house for about £4,000.  That replaces the boiler and provides heat.  I would need a hot water tank (for on-demand hot water) and some plumbing work to complete it, but to get this work done professionally would cost around £12,000.  There are only a limited number of professionals that can do this work, and they are in high demand.  We have really dropped the ball when it comes to skilled trades, instead of sending kids to trade schools we're sending them to get pointless degrees in subjects they don't need or want.  (Rant over.)

Zero999:

--- Quote from: zilp on February 23, 2024, 02:38:44 pm ---
--- Quote from: Zero999 on February 22, 2024, 09:24:50 pm ---
--- Quote from: zilp on February 21, 2024, 09:57:05 pm ---
--- Quote from: Zero999 on February 21, 2024, 08:34:10 pm ---It's nonsense because China, Russia and the USA are never going to adopt net zero.

--- End quote ---

Why not?
--- End quote ---
I'm just not going to discuss net zero, propaganda and taxes. They're political and will just result in pages of arguing, with neither of us agreeing. I just don't support it. You clearly do. We'll just have to disagree and leave it at that.

--- End quote ---

That is simply a lie. You did discuss just that, as I quoted above. You just don't want to defend your position when challenged. If you didn't want to discuss it, you wouldn't have mentioned it in the first place.
--- End quote ---
Now it appears you're tying to provoke me, which will not work. I'm more than capable of defending my position. Indeed I consider it to be fairly obvious.  I just do not want to discuss the matter here any more. For one it's against the rules of this forum and secondly I know from previous experience it's impossible to discuss such matters in a logical manner with those who resort to accusations of lying. It'll just result in pages of arguing, the thread being locked and possibly both of us being banned. It's just not worth the bother.  This is me exercising self-control. There is a part of me that really wants to write a long rebuttal to your post, but I know better.


--- Quote ---
--- Quote from: Zero999 on February 22, 2024, 09:24:50 pm ---On the other hand, I know if I replaced my gas boiler with an electric heat pump, it will lose money, so it would be a dumb investment for me. I'm not going to buy a system which will cost a lot of money and cost more to run. It would be like me trying to persuade you into investing in a new paper magazine publication. It will lose money.

--- End quote ---

It's just that you don't actually know that. Whether replacing a gas boiler with an electric heat pump now is a net profitable decision depends heavily on the development of energy supply costs and the purchase price and installation costs of heat pumps over the lifetime of that (hypothetical) heat pump. And as you don't know any of these to a particularly high degree of certainty, you also can't necessarily know whether installing a heat pump now would lose you money.
--- End quote ---
I have done the calculations,  as has someone else here, who is also an advocate of heat pumps.
https://www.eevblog.com/forum/chat/what-is-the-real-story-around-heat-pumps/msg5347484/#msg5347484


--- Quote ---One thing that is pretty likely, though, for a variety of reasons, is that the price differential between gas and electricity will shrink, and possibly even invert, which at the very least means that betting on gas is not a particularly safe bet.
--- End quote ---
And guess what. If it becomes economical for me to buy an electric heat pump, then can do it. It's just uneconomical at the moment. I don't see why you appear to be having difficulty understanding that.


--- Quote ---
--- Quote from: Zero999 on February 22, 2024, 09:24:50 pm ---
--- Quote ---How did you get to that number?
--- End quote ---

Given:

The gas engine has an efficiency of 30%

The heat pump system a COP of 300%, i.e. for every 100W of mechanical power from the engine, I get 300W of heat.

Calculate the total COP of the heat pump, driven from the gas engine:

100W of power goes in:

The engine is 30% efficient, thus produces:
30W power to the shaft, which is delivered to the heat pump, which generates three times as much heat 30W*3 = 90W
70W of heat, which isn't wasted but goes into my home.

Total heat to my home 90 + 70 = 160W, hence a total COP of 160%

--- End quote ---

... which assumes that the exhaust will be at outdoor temperature (i.e., your heating water return is below outdoor temperature?) and at the same absolute humidity as outdoor air (which indeed would be likely with outdoor-temperature exhaust ... but not so much in reality)!?

Also, I don't know all that much about the power regulation of combustion engines, but I think that they at the very least have a relatively narrow band of rotational speed where they reach maximum efficiency, and I suspect that exhaust temperature is part of that equation and thus can not be varied continuously to match the water heat exchanger without sacrificing mechanical efficiency!?

Which is to say: It seems highly optimistic to me to assume that you could capture 100% of the waste heat for heating purposes.
--- End quote ---
Not highly optimistic, only a little optimistic to assume all of the heat from the engine will heat my home. Perhaps 85%, is a more reasonable figure, similar to a condensing gas boiler. This still a COP of around 150% and is much cheaper to run than electricity of a condensing gas boiler.


--- Quote ---
--- Quote from: Zero999 on February 22, 2024, 09:24:50 pm ---I don't know what the actual cost of a gas powered heat pump is. Yes it would be more expensive, but typically the cost of the heat pump itself is only a small proportion of the total system. At least with a gas powered system, I know it would pay for itself, unlike an electric one. If I've changed my heating to be heat pump compatible and the market changes, I can always move to electric in the future.

--- End quote ---

Uh ... I mean, I am sorry, but ... that doesn't make a whole lot of sense!?

If you work from the assumption that the majority of the costs of switching to a heat pump are independent from the energy source used by the heat pump, then that implies that switching to a gas-driven heat pump would require the same investment as switching to an electrically driven heat pump. And probably at least a bit more, as you seem to agree. Which also presumably is considerably more than staying with your current system/replacing it with a new gas boiler (as otherwise an electric heat pump would be close to cost parity, based on operating costs alone)? And that difference is supposed to be paid for by a reduction in gas consumption of only 38% even based on your own highly optimistic efficiency calculation?!

I mean, I am not saying that it couldn't end up cheaper overall, but I think you are overstating the certainty a lot when you say that you know that it would pay for itself, given the uncertainty of energy supply costs, and the relatively small efficiency gain of a (small) gas-driven heat pump vs. just burning the gas for heat.

--- End quote ---
To be honest, changing to a heat pump, whether it's powered from electricity, or gas wouldn't be worth it for me at the moment because my energy usage is too low for it to matter. It's really a thought experiment.

nctnico:

--- Quote from: zilp on February 24, 2024, 01:24:13 am ---
--- Quote from: nctnico on February 24, 2024, 12:59:57 am ---There is no such thing as a delicate balance.

--- End quote ---

You are aware that you are in disagreement with about everyone who does research in that area professionally, right?

--- End quote ---
Citation needed... Maybe you should actually do some research into the subject like I did for over 25 years already.

If you start looking carefully you'll notice that a lot of data is being filled in by assumptions and thus the 'conclusion' is only an assumption. Trying to model something erratic as weather / climate is next to impossible so anyone claiming to have an absolute truth in that area is leaving out a lot of details which may even prove that person wrong. There are some long term effects (like recurring CO2 peaks every 40000 years, long term/short term sun cycles, cold / hot periods centuries ago, etc, etc) which are not explained by models used for global warming. In the end global warming predictions are a line fitted onto the temperatures from the last 100 years with the assumption that CO2 levels are the major factor driving the temperature up.

In fact, there are several other way more pressing issues which make that we should stop burning fossil fuels:

1) Burning fossil fuels is very bad for our health. We should have switched to nuclear a long time ago. Even with some more nuclear power plants blowing up, this would have saved and continue to save millions of lifes.

2) The CO2 level in the atmosphere is creeping up to levels where CO2 becomes toxic to humans, animals and even plants. Look at the coral reefs as an example.

3) Fossil fuels are finite. Once they run out, there has to be an alternative or society will collapse.

4) Taking rising CO2 levels out of the equation as a cause of continued global warming.

Now look at this list through the eyes of a politician. Fear is an effective driver to make people vote for you. So which point to latch onto for a fear mongering campaign? Point 1 will get a lot of pushback from environmentalists who are dead set against nuclear. CO2 toxic? Finite fuels? Global warming? Global warming has a nice ring to it and there are alarmists claiming the world will end if we don't do something so that is free publicity. Notice that the effects of global warming are on the longest term of all the points I listed and there is no certainty stopping burning fossil fuels will actually stop global warming.

IOW there is a good reason that people are getting fed up with fear mongering and start to vote for right wing politicians which want to continue burning fossil fuels. In turn this circles back that renewable energy sources and reduction of energy usage needs to be made cheap enough for the masses.

Zero999:

--- Quote from: Someone on February 24, 2024, 02:04:47 am ---
--- Quote from: johansen on February 24, 2024, 01:31:25 am ---Is this what this forum has become?  5% useful posts on actual heatpump data, 95% argument?

--- End quote ---
Something about heatpumps brings out the crazies, not just this forum. So the OP asking for honest answers (being overwhelmed by the noise) is fully understandable.

--- End quote ---
Because it's political. I'm not going to get into who's right and wrong in this post, just explain why many get emotional about it, briefly outlining both points of view.

Many western governments are implementing net zero policies and are pushing associated technologies such as heat pumps and electric cars. On one side there are those who strongly support such measures, which they see as important to combat the existential threat posed by climate change.  On the other side, there are those who see such policies as unwanted state interference and authoritarianism and that it is such governments themselves who are the existential threat, rather than climate change.

Someone:

--- Quote from: Zero999 on February 24, 2024, 10:45:39 am ---
--- Quote from: Someone on February 24, 2024, 02:04:47 am ---
--- Quote from: johansen on February 24, 2024, 01:31:25 am ---Is this what this forum has become?  5% useful posts on actual heatpump data, 95% argument?

--- End quote ---
Something about heatpumps brings out the crazies, not just this forum. So the OP asking for honest answers (being overwhelmed by the noise) is fully understandable.

--- End quote ---
Because it's political. I'm not going to get into who's right and wrong in this post, just explain why many get emotional about it, briefly outlining both points of view.
--- End quote ---
But the only politics seems to be in the supply/price of natural resources. Nothing to do with the heat pump.

All it needs is people plainly stating the reason why they think their position, instead of non specific unarguable generalisations.

Most of this thread is UK people dodging the fact that their energy costs are abnormal, while making all sorts of big claims about the rest of the world. Obnoxious colonialism vibes.

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