Heat pump questions

[JamesPa]

48 minutes ago, Beelbeebub said:

All good points but I was thinking more along the lines of allowing HPs to be installed alongside an *existing* boiler system and still qualify for a grant (maybe with different amounts and stipulations about upgrading the rads). Rad upgrades would make the existing system more efficient as well. 

 

Fitting a new system as a hybrid should not be done. 

 

By allowing "piggyback" installs we can sidestep the "why throw out a good boiler" argument as well as the "but what if the HP can't keep me warm in the depths of winter" one. 

 

The HP can then be undersized, or at least not oversized, making it cheaper and more efficient. It can work for most of the year and when it gets to it's limit the existing system kicks in. 

 

The control system can prioritise the HP to run only when it is cheaper than gas, ie the conditions allow high cop.

 

This negates the "costs more to run" argument. 

 

It woiod also allow installs with combis and sidestep the hot water problem. 

 

Finally, when the existing boiler packs in it can be replaced by *another* HP of appropriate size (by then the control system would have a good idea of actual demand). This woukd result in a twin HP system, theoretically more expensive and complex but in practice not so bad as it would be installed in stages. It would then have the huge advantage of a bigger modulation range than a single HP. 

 

If the grant could make the install more or less free, then the proposition would be 

 

"hey, can I fit this gizmo to your heating system for free that will make it more efficient and cheaper to run?" 

 

I reckon people woukd be biting your hand off. 

 

 

Really doubtful about this being good use of public money for the reasons set out in detail in my post above.

 

[SimonD]

11 hours ago, Onoff said:

Like a hybrid heat pump?

 

Very sensible as a transitional technology option. The reality on the ground is that here in the UK we have an intractable problem with heating and hot water which is not easily resolved by fabric alone, nor is it a binary choice of fossil fuel/heatpump.

 

80% of boilers (about 1.2 million per yer) installed are combis and across the country we have about 23 million homes with gas boilers installed, 80% of which are combis. So not only would we need to be installing nearly a million heat pumps per year to get rid of just our gas boilers by 2050, we'd also have to be resolving satisfactory hot water provision in many households where a hot water cylinder and/or necessary buffer isn't an option, including many newbuilds as they haven't been designed with sufficient spare room, unless they lose a spare room.

 

To do this we would also have to change the whole economic model of energy across the UK as it is currently skewed in favour of gas v electric and we have to invest significantly in infrastructure, especially if impractical evangelists suggest direct electric heating for hot water - I was just having a conversation with an electrician yesterday about the installation realities of electric boilers and combis which is an entirely different story....which unfortunately doesn't involve a plug and 13amp socket.

 

Now working in the industry, I've been astonished by the lask of joined up thinking across the whole spectrum from policy makers, to the instrustry, to the evangelists......

Edited October 19, 2023 by SimonD

[SimonD]

16 hours ago, SteamyTea said:

No

 

Of course, my memory is flawed and behind the times. It was from DRC that the fuel for the Hiroshima and Nagasaki bombs was sourced. Knew it was of some historical significance...

[sharpener]

14 hours ago, Beelbeebub said:

Nuclear is costly, but mainly because we piss about "shall we shan't we". That add cost and uncertainty to suppliers who then have to pass thar cost on to the end unit price. 

 

I have a friend who used to work for the consortium(s) hoping to build a replacement plant at Wylfa on Anglesey. Hundreds of millions were spent on that project for it to be canned. The next lot will look at that and add a few hundred million into their calculations. 

 

Sorry, I come late to this discussion as have been away.

 

It's a tribute to the original engineering of the AGR stations that they have been able to have their life extended several times. Had we pressed on with them (or indeed continued with the PWR programme after Sizewell B was up and running as originally intended) we would now be in a much better supply position.

 

But they are expensive, no denying it. I worked on secondment to the govt Nuclear Review in the 90s. It was totally rigged, the principal external consultancy in Oxford was deliberately chosen for their free market economy perspective. The report came out in favour of all the risk being borne by the private sector, which hasn't happened and was never going to. When it was published the civil servant in charge of the Review left to go and work for the said consultants. You couldn't make it up if you tried.

 

As an aside I remember the research included the fact that the UK manufactured content of AGR stations was much higher and the import content was lower than the alternatives.

 

However any project that involves careful engineering in mud and rain on windswept coastal sites is going to be difficult and expensive. IMHO the small modular reactor approach was always the way to go, though I have my doubts that the RR Nuclear approach is small enough or modular enough to realise the benefits. The compact PWRs that are fitted in submarines are a better illustration of what can be achieved.

 

[ProDave]

Let us not forget up until the 80;s the UK was a world leader in the design and construction of our own reactors.  Some very short sighted thinking shut down the UKAE as not necessary.  Now you know why we have to buy in any new reactors, designed and largely built outside the UK.

 

Of course I don;t have a chip on my shoulder.

[Dillsue]

15 hours ago, Beelbeebub said:

We need to massively ramp up wind and solar and (this is the controversial bit) state owned CCGT plants and gas storage as a national resource to cover any generation gaps as we transfer demand from gas to electricity and to provide cover for the time when wind/solar aren't sufficient 

Not sure it's going to be state owned but last BEIS forecast figures I saw for gas generation showed 19% in 2040 and 14% in 2050, hopefully all with CCS.

[SteamyTea]

45 minutes ago, Dillsue said:

hopefully all with CCS.

CCS is like hydrogen, it is not worth doing.

 

[Dillsue]

1 hour ago, SteamyTea said:

CCS is like hydrogen, it is not worth doing.

 

I don't know if CCS will work at scale but clearly some do as there's a 3 foot dia CO2 pipeline planned to run past us next year to dump CO2 in disused gas fields off the N Wales coast.

[JohnMo]

Notice the original poster of this thread was on the site specifically to post this and not been seen since. Was on the site about 5 mins in total.

[Beelbeebub]

3 hours ago, ProDave said:

Let us not forget up until the 80;s the UK was a world leader in the design and construction of our own reactors.  Some very short sighted thinking shut down the UKAE as not necessary.  Now you know why we have to buy in any new reactors, designed and largely built outside the UK.

 

Of course I don;t have a chip on my shoulder.

The pro em is/was thrat the AGR tech the UK used was not a great fit for civil power. 

 

I was told by one of the engineers who had been there from the start (he was in his late 60's and about to retire) the primary driver of the decision to go with gas cooled, graphite moderated was because it was good at making stuff for weapons. The "oh look we can make civil power" but was mostly PR fluff. 

 

That's not to say they couldn't make good power stations, tgry did, but that the tech "tree" chosen was not one ideally suited for civil power. 

 

The AGRs were kept running past their design life by a huge effort of engineering to understand and measure the stability of the graphite cores, which were becoming dangerously brittle by the mid '00s

 

I think it is and was a dead end technology. 

 

The small modular reactors show promise. My understanding is they are basically (sub) marine power plants repurposed for stationary land use. 

 

The biggest hurdle will be the regulations and, by extension, the politics. 

 

There is a certain percentage of the population who are, rightly or wrongly, implacabley against nuclear power full stop. 

[Beelbeebub]

3 hours ago, JamesPa said:

Really doubtful about this being good use of public money for the reasons set out in detail in my post above.

 

Your core argument against seems to be that the user will continue to use the gas boiler in preference to the HP. 

 

But they won't really have a choice, short of disabling the HP outright. 

 

The control system handles which source provides heat. On a mild day like today, it will heat the house via the HP. The user will be none the wiser. The house will be warm and less gas will have been burnt. On the occasions where the conditions are too much for the HP, the boiler kicks in and the house remains warm but burns a bit more gas. 

 

It's a win from a carbon perspective and from a consumer perspective as their bills will go down (unles they disable the HP, in which case their bills will remain the same). As upgrading the rads would be a part of the install (paid for by not having to sort out a new DHW system) the house woiod also be more efficient. 

[JamesPa]

4 hours ago, Beelbeebub said:

Your core argument against seems to be that the user will continue to use the gas boiler in preference to the HP. 

 

But they won't really have a choice, short of disabling the HP outright. 

 

The control system handles which source provides heat. On a mild day like today, it will heat the house via the HP. The user will be none the wiser. The house will be warm and less gas will have been burnt. On the occasions where the conditions are too much for the HP, the boiler kicks in and the house remains warm but burns a bit more gas. 

 

It's a win from a carbon perspective and from a consumer perspective as their bills will go down (unles they disable the HP, in which case their bills will remain the same). As upgrading the rads would be a part of the install (paid for by not having to sort out a new DHW system) the house woiod also be more efficient. 

If the choice is controlled by the system then I accept my argument falls.  However upthread it was stated that the user could choose 'whichever they want'.  Also if hybrid is grant funded is there not a risk of token heat pump installs.  The rules would need to be very carefully written and policed otherwise you have the pump installed, claim the grant, then take it out and sell it .  Also I can't see it's necessary for the majority of the UK housing stock for which 8kW suffices.  The exception I might make would be retaining a combi for dhw only until we have a more sane solution for this use case, but then only where there wasn't a practical alternative.

Edited October 19, 2023 by JamesPa

[JohnMo]

Government report from 2017 on the hybrid situation 

Hybrid_heat_pumps_Final_report-.pdf

[JohnMo]

And more on the subject

 

https://www.rehva.eu/rehva-journal/chapter/hybrid-heat-pumps-saving-energy-and-reducing-carbon-emissions

[Onoff]

Could I take the door off of my fridge, remove a similar size window and wedge the fridge in the hole, then seal all round the edge? 

 

Given the thread title I thought I'd ask...

[SteamyTea]

11 minutes ago, Onoff said:

Could I take the door off of my fridge, remove a similar size window and wedge the fridge in the hole, then seal all round the edge? 

 

Given the thread title I thought I'd ask...

I said something similar a while back about using an old freezer.

Then Jeremy Harris, who was a clever bloke, pointed out that a large freezer probably only draws about 700W. So 2.1 kW if CoP is 3.

Would still heat my DHW just about.

[Beelbeebub]

1 hour ago, JohnMo said:

Government report from 2017 on the hybrid situation 

Hybrid_heat_pumps_Final_report-.pdf 2.76 MB · 0 downloads

From that it looks like a hybrid HP of about 5kw could provide carbon savings of upto 50% vs continuing with a gas boiler.

the two big determining factors seemed to be the radiators (if they are unchanged and require high temps it drastically reduces the number of days a HP can provide heating, which is compounded by control strategies that switched entirely to boilers when the HP was unable to meet all the demand rather than using the boiler to "top up" the output) 

 

The second factor was thought to be running the heating in short bursts which required higher flow temps and hence lower efficiencies and more days when the boiler was used instead of the HP.

 

It estimated the cost of installing a HP alongside an existing boiler, including upgrading radiators, to be £5-7.5k.

 

So it would be within the current BUS £7.5k grant to provide a HP and upgrade the rads at little cost to the owner and cut the carbon output by upto 50% without any risk of "being cold" or costing more.

[Dillsue]

3 hours ago, SteamyTea said:

I said something similar a while back about using an old freezer.

Then Jeremy Harris, who was a clever bloke, pointed out that a large freezer probably only draws about 700W. So 2.1 kW if CoP is 3.

Would still heat my DHW just about.

And if you put one in each window??

[JohnMo]

14 minutes ago, Dillsue said:

And if you put one in each window??

You would have a dark ugly house! Everyone would laugh at.

[Beelbeebub]

13 minutes ago, JohnMo said:

You would have a dark ugly house! Everyone would laugh at.

It wouldn't be dark, the fridge lights would be on! 😁 

[SteamyTea]

7 hours ago, Beelbeebub said:

It wouldn't be dark, the fridge lights would be on

Light would be on the outside though.

7 hours ago, JohnMo said:

You would have a dark ugly house

I have an ugly house already.

[Post and beam]

23 hours ago, sharpener said:

The compact PWRs that are fitted in submarines are a better illustration of what can be achieved.

When i lived on one of these the fuel would last about 5 years. So the refit period was 5 years, ish. I understand that the modern boats fuel lasts for the life of the boat. Small modular, if its suitable for PWR reactors, would perhaps not need taking away for a refuel very often. Might turn out to be a good solution.

[SteamyTea]

9 hours ago, Post and beam said:

I understand that the modern boats fuel lasts for the life of the boat.

I read in my weekly comic a few years back that small reactors are not as fuel efficient as large ones.

This is not an unusual situation in energy production, and should not be a reason to not use them.

They are probably much lower on CO_2e emissions overall compared to natural gas, and that should be one of the overriding reasons to use them.

Wind and Solar will still be cheaper, and I am sure that battery storage will get cheaper in the next decade, as long as we stop pretending that the best 'fuel', which we all know is Hopium, is just about to be invented.

[Crofter]

There's lots of hype around Small Modular Reactors, but as far as I can tell they've yet to actually prove themselves. It seems a matter of faith that mass production will offset the economies of scale of larger units.

 

Can SMRs be made to fit any site, without the need to access water sources etc? That would be a huge advantage.

[sharpener]

3 hours ago, Crofter said:

There's lots of hype around Small Modular Reactors, but as far as I can tell they've yet to actually prove themselves. It seems a matter of faith that mass production will offset the economies of scale of larger units.

 

They have been used for submarine propulsion for decades, though they have only been ordered a few at a time and been made in small numbers of any one design so no mass production as such.

 

I think it is perfectly reasonable to think that in the long term making them in factory conditions should be cheaper and much more reliable that trying to weld the full thickness of a containment vessel in the middle of a muddy building site. The current PWR designs really stretch the limits of what can be achieved in terms of fabricating large pressure vessels and this has caused a lot of re-work and cost overruns.

 

3 hours ago, Crofter said:

Can SMRs be made to fit any site, without the need to access water sources etc? That would be a huge advantage.

 

No, various methods of cooling the reactor have been proposed including gas, liquid metal, molten salts and water for transferring the heat to the turbines, but they still need cooling water as the ultimate heat sink as the thermal efficiency is ?50% at best so half the reactor output is rejected to the environment. Cooling towers could be used at inland sites, and air cooling is theoretically possible but I have not seen it proposed seriously. Though the original piles at Windscale were built just to produce weapons-grade plutonium so none of the heat was used and all 180MW of it was rejected up the massive 400 ft chimneys, one of which was heavily contaminated after it caught fire in 1957 (I have been up the other one!).