Heat pumps won’t work in old homes, warns Bosch

[ReedRichards]

11 minutes ago, JamesPa said:

What did I miss?

 

Perhaps the fact that a gas turbine power station converts gas to electricity with an efficiency of just under 50%?  So if we already waste energy like that, why not find other was of wasting energy? 

[Roger440]

15 minutes ago, JamesPa said:

I haven't followed the hydrogen debate until now, but I'm getting interested.  As I understand it the advocates are suggesting we use electricity to generate hydrogen from water, yet it takes more electricity than the energy you get from burning the hydrogen.  How can that ever be a sensible way to distribute energy?  

 

If I understand it right they are taking us for fools.

 

What did I miss?

 

Because it can all be done, well mostly, through existing infrastructure. From that point of view, it makes sense (see my post above).

[ProDave]

9 minutes ago, Post and beam said:

Ta. They used to call them PWR on the boats then. Pressurised water reactors. Perhaps a different design now, it was a long time ago

The UK had a whole series of home designed and built reactors from the early Magnox upwards and 30 years ago we could have designed and built our own new generations of power stations.

 

Now the only relic of that is the small PWR's that only lived on in the subs.  the last remnants of our own nuclear industry.

[Roger440]

1 minute ago, Roger440 said:

 

Because it can all be done, well mostly, through existing infrastructure. From that point of view, it makes sense (see my post above).

 

Mind you, all acedemic, because starmer has said no more burning of fossil fuels in domestic settings by 2030.

 

This i have to see happen. Turning of the gas supply t 20 odd million homes. 7 years from now.

 

Who advises these people?

[ProDave]

1 minute ago, Roger440 said:

This i have to see happen. Turning of the gas supply t 20 odd million homes. 7 years from now.

 

Who advises these people?

Of course it won't happen.  The plan is to get the votes of the gullible who believe it will, and then figure out who to blame other than themselves for it not happening.

[Post and beam]

4 minutes ago, Roger440 said:

Mind you, all acedemic, because starmer has said no more burning of fossil fuels in domestic settings by 2030.

He will never be in a position where anyone will care what he says. or whoever replaces him.

 

Oh bugger i always stay quiet on political points.... Until now aparently.

[Iceverge]

30 minutes ago, Roger440 said:

you could properly insulate an old solid wall house, properly, without creating a load of new issues, for £25k. 

 

 

 

Wrap the whole building in plastic in situ. Guttering, slates, birds nests the lot . Nothing too technical, maybe like that black stuff they put on pallets, or bales of grass silage. It should be reasonably durable once out of the sunlight. 

 

Erect a 4 post portal frame outside it with a metal pitched roof. Then wrap the frame in some of that cement impregnated fabric they use for military huts and canal reinforcement. Wait for a rainshower to allow it to set .Then pump the void in between with EPS beads. 

 

Exhaust source heat pump for DHW and ventilation and A2A for heating. 

 

Windows and doors optional. 

 

 

 

 

 

 

 

 

 

 

 

 

[Dillsue]

5 hours ago, Iceverge said:

Adding solar production to balance high winter losses caused by poor building fabric exacerbates emissions until we have some viable interseasonal energy store. 

 

Take house 1, a glass masterpiece with poor form factor and average glazing etc. Uses 10000kWh per annum for space heating but thanks to a generous solar array generates 8000kWh in the summer. 

 

House 2 has no PV but is super insulated. 2000kWh/ year space heating.  They have the same EPC rating but there is an 8000kWh difference in bought in winter electricity say at 50% fossil fuels means the solar PV house would use 4000kWh more of FF energy. Bonkers. 

 

 

I'm not sure that's correct. If you look solely at winter then house 1 does look bad but net result is the same for both houses when you look over the year. During the summer house 1s PV exports a significant proportion and displaces gas generation used by others, maybe even house 2s AC  or EV charging.

 

[Levo]

2 hours ago, IanR said:

 

Not in Berkshire you don't. I can't imagine there're many days a year where the average temp is less than -3°C.

Well, what can I say.

1- I'd like to be prepared. 😁 And why do we need, at least some of us, 300BHP cars?

2- Being an engineer, having some margin has never hurt. If you are spending £15K on a system, what is another grand or two to have that buffer.

3- Also, as I said, I don't quite believe the manufacturers figures. They are a bit like car's MPGs. Only valid on a downhill slope, on a cold day with the wind behind....

[sharpener]

2 hours ago, Post and beam said:

Ta. They used to call them PWR on the boats then. Pressurised water reactors. Perhaps a different design now, it was a long time ago

 

Still basically the same technology to this day. (I used to work for S & H who supplled all your u/w weapons handling gear so have been on quite a few boats whilst alongside including SSNs.)

 

2 hours ago, ProDave said:

The UK had a whole series of home designed and built reactors from the early Magnox upwards and 30 years ago we could have designed and built our own new generations of power stations.

 

Now the only relic of that is the small PWR's that only lived on in the subs.  the last remnants of our own nuclear industry.

 

Yes, a lamentable tale. But our Magnox and the later AGR stations all used CO2 as the heat transfer medium, at a pressure that achieved a density about half that of water. (S & H also made the refuelling machines which load the 4 tonne fuel strings into the reactors whilst they are still under pressure.)

 

For Sizewell 'B' we abandoned all this know-how and the UK had to license the pressurised water reactor design from Westinghouse in the US.  That is basically the same technology as the submarine reactors, these were originally licensed from the US as well, though AFAIK the design and manufacture are now independent.

 

Hot off the press: nuclear power is now officially classified as "envionmentally sustainable". About 20 years too late.

 

Edited March 15, 2023 by sharpener

[IanR]

1 hour ago, Levo said:

Well, what can I say.

1- I'd like to be prepared. 😁 And why do we need, at least some of us, 300BHP cars?

2- Being an engineer, having some margin has never hurt. If you are spending £15K on a system, what is another grand or two to have that buffer.

3- Also, as I said, I don't quite believe the manufacturers figures. They are a bit like car's MPGs. Only valid on a downhill slope, on a cold day with the wind behind....

 

As an Engineer, surely you'll:

1. Calculate what your property actually needs and have confidence in your calculation, you're not buying a ASHP to fulfil a mid-life crisis (not that 300bhp would achieve that goal)

2. Research the subject and find an over-sized ASHP requires mitigation measures to over-come the associated short-cycling which could have an effect on the systems efficiency that might make you assume the manufacturer's figures are inaccurate. Done well, there's no reason why they would have an efficiency hit, but there's lots of opportunities to get this bit wrong.

3. Research the standards the SCoP figures are tested under and gain more confidence in their validity. Much like car's published MPG figures, their correct under the test conditions, but if you drive them different to the test then expect a different result. (Yes, I appreciate that ignores a deliberate attempt to circumvent the test parameters, but you can't be that cynical and assume every manufacturer in every industry is doing similar)

 

Those on the forum that have put the effort in to calculating energy losses and planning the emitters system to deliver the planned flow temp seem to have found the manufacturer's figures can be relied upon for sizing their heat pumps.

Edited March 15, 2023 by IanR

[sharpener]

1 hour ago, Levo said:

Well, what can I say.

1- I'd like to be prepared. 😁 And why do we need, at least some of us, 300BHP cars?

2- Being an engineer, having some margin has never hurt. If you are spending £15K on a system, what is another grand or two to have that buffer.

3- Also, as I said, I don't quite believe the manufacturers figures. They are a bit like car's MPGs. Only valid on a downhill slope, on a cold day with the wind behind....

 

As @IanR suggests, being an engineer also involves wanting to have system designs that combine known technolgies in novel ways, are elegant, and do not waste resources. Which is why I am slowly working out how to optimise a heat pump installation for a sprawling barn conversion. So I would rather have to fire up the woodburning stove and the 3kW fan heater on 2 days a year than over-engineer it for an OAT of -15C.

 

Edited March 15, 2023 by sharpener

[ProDave]

Going back to EPC ratings and properties requiring upgrades, I am following a thread on another forum.  I can't post a link as it is a members only forum so would not show to any non member.

 

That thread has shown that the original EU "Energy Performance of Buildings" directive, some 15 years ago which is what gave us the EPC in the first place, has provision for demanding all buildings are updated to certain standards by certain dates.

 

It also appears that we are still obliged to follow that directive, even the amendments to it that may alter what standards a building has to meet and when.

 

We seem to have a lot of silence on this here, no mention of it in the UK main media but it is being talked about openly "over there"

 

If in a number of years time, it is suddenly announced to the UK public that you WILL have to upgrade your old house (estimates are 75% of the UK housing stock WILL need upgrades) and YOU might have to pay for the upgrades yourself, then there are going to be a lot of angry people.  What's more I estimate a little over 50% of the population will become even more angry when they find out it is an EU law that is still telling us what we must do.

 

[SteamyTea]

2 minutes ago, ProDave said:

I can't post a link as it is a members only forum so would not show to any non member.

You can copy and paste the content.

Or put the link up and we can join.

[Sparrowhawk]

11 hours ago, Iceverge said:

Wrap the whole building in plastic in situ. Guttering, slates, birds nests the lot . Nothing too technical, maybe like that black stuff they put on pallets, or bales of grass silage. It should be reasonably durable once out of the sunlight. 

 

Erect a 4 post portal frame outside it with a metal pitched roof. Then wrap the frame in some of that cement impregnated fabric they use for military huts and canal reinforcement. Wait for a rainshower to allow it to set .Then pump the void in between with EPS beads. 

 

Exhaust source heat pump for DHW and ventilation and A2A for heating. 

 

Windows and doors optional.

I like it.

We've got to lose our obsession with houses being beautiful in the UK. And by that I mean lots of brick, quaint-cottagey modern builds, that planning committees love judging by the fights people on this forum have to get designs passed. The continent survives fine with rendered everything (pretty on some but the new estates in Normandy aren't) and heading for the same look would make EWI retrofit - done this way or other ways - cheaper.

 

I am amused when I meet people who are vocal about "buccaneering Britain" but also "preserving our built heritage". If we really wanted to be that country we'd stop holding progress back and get on with knocking stuff down and rebuilding without a second thought, as they did in previous, more "bucaneering" times.

 

Rant over

[ProDave]

3 minutes ago, SteamyTea said:

You can copy and paste the content.

Or put the link up and we can join.

For those wanting to join a boating forum in order to read it https://forums.ybw.com/index.php?threads/epc-energy-performance-certs.593805/

 

The opening post of the thread was 

Quote

It looks like there are changes afoot and our buildings, commercial and residential will gradually be forced to make energy efficiency improvements. Not only to new buildings but exisiting buildings.

Part of the change is a new way of defining the EPC ratings as energy used per year per sq.m of a building. Rating A is less than 50kWh/m2 is very efficient, B is 50 - 90 kWh/m2 and is good etc all the way to G rating which is in excess of 450 kWh/m2 which is considered a heat sink.

My house was given a D rating when I bought it. It's old and has solid walls etc, so, short of rubbling it down, that's about where the rating will stay. D rating is 151 - 230 kWh/m2. I've now calculated my real annual energy consumption per m2 and I come in at 90 kWh/m2 which means my house is now EPC B rated. So, I've jumped up two rankings in efficiency.

Viago's house will be even better at EPC rating A because he refuses to put on the heating!

Anyhow, that aside, come 2050, all houses will be forced to be carbon zero and by 2030 must demonstrate a 55% reduction in greenhouse gases. So, it looks like I will need to rubble my house down and build a modern carbon zero house. Maybe even by 2030, I'll need to rubble it down and re-build because technically, I cannot see how to reduce my GHG emission by 55%. That's in 7 years time. If I don't, what will happen?

 

 

[George]

14 hours ago, Levo said:

The problem with AirSource HP is that as it gets cold, the efficiency suffers, so you are not able to supply the quoted heat while at the same time your need is increasing. So the system needs to be sized to be able to deliver the required energy at -15C. Otherwise you are toast, well I mean frozen!. I am not sure how realistic the cold temp figures the manufacturers are quoting. I know one needs to take any claim with a pinch of salt but besides that, what if their figures are for somewhere with drier air (lower humidity). That would delay any ice forming on the fans/radiators, therefore improving efficiency. That wouldn't apply to your usual UK weather with near 100% humidity almost every night throughout the winter...

As an example, I have friends with a new (less than 10 year) house. I live in a ~50 year old house (maybe 30% smaller than theirs). Assuming their house is much better insulated, I figure they should need less energy to heat their house and at worst, the same amount of heat as we do. In our house we only turn on some of the downstairs radiators, around 5KW max output, and we never have any issues with not being warm. If anything the rest of the lot complain I keep the TV room too warm. I changed all the radiators recently, so know their heat output.

My friends on the other hand keep complaining they are never warm on a cold night. So, their system appears not to be able to supply 5 KW. Their outside unit is rated at 15KW!!!

So to me, Air source HP is good for mildly cold days but you need some backup for the real cold days. Best solution as the others suggested, install couple of A2A units which will do a lot of the heating and at peak times, use the boiler to back them up. Problem solved for 2-3 grand and fully prepared for that cold day.

Designing for a absolute worst case once in a 10 year event like -15C (where I live, anyway) is no way to design a heating system. Plug in a fan heater if it gets that cold.

 

 

I've successfully renovated an 1880s detached cottage to work with a  ASHP. Three winters and running costs are comparable to oil, very comfortable and has been fine in the -6 to -10C we got last year. Yes costs increase in the very cold but on average it is better than the oil system

Edited March 16, 2023 by George

[saveasteading]

3 minutes ago, Sparrowhawk said:

The continent survives fine with rendered everything

Have you seen recent Scottish estates, and new builds?

White render almost without fail.

[Sparrowhawk]

1 minute ago, saveasteading said:

Have you seen recent Scottish estates, and new builds?

White render almost without fail.

I haven't, I'll look out for them this summer when we're up visiting Skye - Inverness - Cairngorms.

 

On previous trips, Scotland has felt closer to France than England in many good ways, and I should have scoped my rant to England!

[Post and beam]

10 hours ago, sharpener said:

boats

So glad you said 'boats'.  and not that other word. You'll know why

[saveasteading]

3 minutes ago, George said:

14 hours ago, Levo said:

The problem with AirSource HP is that as it gets cold, the efficiency suffers, so you are not able to supply the quoted heat while at the same time your need is increasing. So the system needs to be sized to be able to deliver the required energy at -15C. Otherwise you are toast, well I mean frozen!. I am not sure how realistic the cold temp figures the manufacturers are quoting. I know one needs to take any claim with a pinch of salt but besides that, what if their figures are for somewhere with drier air (lower humidity). That would delay any ice forming on the fans/radiators, therefore improving efficiency. That wouldn't apply to your usual UK weather with near 100% humidity almost every night throughout the winter...

As an example, I have friends with a new (less than 10 year) house. I live in a ~50 year old house (maybe 30% smaller than theirs). Assuming their house is much better insulated, I figure they should need less energy to heat their house and at worst, the same amount of heat as we do. In our house we only turn on some of the downstairs radiators, around 5KW max output, and we never have any issues with not being warm. If anything the rest of the lot complain I keep the TV room too warm. I changed all the radiators recently, so know their heat output.

My friends on the other hand keep complaining they are never warm on a cold night. So, their system appears not to be able to supply 5 KW. Their outside unit is rated at 15KW!!!

So to me, Air source HP is good for mildly cold days but you need some backup for the real cold days. Best solution as the others suggested, install couple of A2A units which will do a lot of the heating and at peak times, use the boiler to back them up. Problem solved for 2-3 grand and fully prepared for that cold day.

Expand  

Designing for a absolute worst case once in a 10 year event like -15C (where I live, anyway) is no way to design a heating system.

My understanding is that most machinery works best at about half to 3/4 speed. So designing for an extreme is sensible as it will cope for that short time, albeit less efficiently. But most of the time it will be running optimally.

I think many people, esp non numerate journalists, don't understand that plentiful heat is still present in the air at -15° as we all understand ice, but not absolute zero (-273°).

[ReedRichards]

22 hours ago, ProDave said:

...The EPC system is being overhauled...

 

I don't know if this has been mentioned on this thread or elsewhere but I read on another forum that an ASHP will now boost your EPC rating, rather than downgrade it as hitherto.  This had been flagged as a change that was coming but it seems it has happened now.

[George]

6 minutes ago, saveasteading said:

My understanding is that most machinery works best at about half to 3/4 speed. So designing for an extreme is sensible as it will cope for that short time, albeit less efficiently. But most of the time it will be running optimally.

I think many people, esp non numerate journalists, don't understand that plentiful heat is still present in the air at -15° as we all understand ice, but not absolute zero (-273°).

Absolutely. But that's more like -2C (depending where you), plus there's fat built in at each stage, especially using the MSC approaches. There is a downside to oversizing as in the majority of normal mild conditions, efficiency could be impacted, eventually costing more than the back up fan heater would have...

 

It does depend a little on how able you are to sacrifice comfort or convenience in response to extreme conditions. Even with small children I don't mind, but the elderly or those who just want the system to work with minimal interaction you could justify a bit more over-design. 

[Iceverge]

13 hours ago, Dillsue said:

I'm not sure that's correct. If you look solely at winter then house 1 does look bad but net result is the same for both houses when you look over the year. During the summer house 1s PV exports a significant proportion and displaces gas generation used by others, maybe even house 2s AC  or EV charging.

 

 

Yes you're right. If you add grid losses at about 7-8% into it where do we end up? 

 

 

[Roger440]

9 hours ago, George said:

Designing for a absolute worst case once in a 10 year event like -15C (where I live, anyway) is no way to design a heating system. Plug in a fan heater if it gets that cold.

 

 

I've successfully renovated an 1880s detached cottage to work with a  ASHP. Three winters and running costs are comparable to oil, very comfortable and has been fine in the -6 to -10C we got last year. Yes costs increase in the very cold but on average it is better than the oil system

 

Better than oil in what way?