ASHP – Should do better - Must Do Better

TiredGeek

To be fair, these things are fitted by councils to council housing and THEY should have someone who has the knowledge to correctly specify the system or at the very least understand what they're buying. There is a whole department in local authorities that deal with this sort of thing, and they're not paid peanuts either, surely they could do the job instead of just taking the easy option of "it's cheap, I've been told it'll work by the builder".

This is tax payers money they are throwing away because they failed to research what they were buying, either that or they mysteriously got a nice new BMW / payed their mortgage off during the buying process.

I know of one company who is doing a lot of work for councils having to rip out unsuitable units and fit things that work.

Oh, BTW, £10 / day, I wish!

TiredGeek

Peterg, I would think if you are wanting to use a hybrid system you'd need a low loss header or even a buffer tank in the system. Either will do what you need and a LL header is easiest.

Plumb the ASHP and the oil boiler into the header, then take off for DHW and radiators. The header will deal with flow issues through the ASHP while the oil boiler can be used in the very coldest conditions when the ASHP is least efficient.

Don't get me wrong, it's not dead easy, but it is do-able for a good plumber...

John_Pierpoint

lardconcepts wrote: »

When I asked the engineer if most people get a bit baffled by all this technical stuff, he said that most customers who he had fitted for, were fairly technical and interested anyway. But of course - it shouldn't be that hard.

I'd imagine social housing would be the very last place you'd want to install heat pumps, being that they're the places most likely to have people running their heating full pelt and opening windows to adjust the temperature. (Personal experience having visited a lot of places - the people least able to afford heating are the people with the highest bills who understand heat loss the least. And then to believe myths and nonsense like "it's cheaper to have the heating on all the time" because a bloke down the pub once said it).

From what I've seen, heat pumps really aren't "set and forget", yet, nor should they even be considered when mains gas is available.

I agree with this thread title - just to add "can do better" in the middle.

Every household would need at least one occupant who understands how the heating works and appreciates that it is incapable of producing instant high grade heat. This expert user must know how to (re) set the system,
Otherwise sooner of later grannie, the baby sitter or the menopausal housewife having a hot flush, will meddle with the settings and the system will be back to square one. Ineffectively trying to deliver on demand heating.

[Deleted User]

I would have thought they are pretty much set and forget.

Once the heat curve and temp set backs are input it is pretty much hands off unless you want to say boost DHW.

With us you have to up the loft for all the complex settings. The wireless unit/wall unit downstairs just do the timer/room temp i.e. same as modern GCH so not the end of the world if adjusted.

I guess having fancoils though does make it pretty much on demand heat. UFH/large rads are likely to have a much slower response time.

waltsalt

For Cardew's reference - http://goo.gl/GhB1e3.

Phase 2 of the Energy Saving Trust's heat pump trials.

Cardew

Thanks for this report.

Anyone contemplating a heat pump should read it thoroughly; in particular the 'advice to consumers'

The main conclusion of Phase 2 of the trial is that 'they' are doing better. It seems the term COP has now been replaced by the more appropriate SPF(System Performance Factor). albeit 3 definitions of SPF

For the Phase 2 trial the average SPF was 2.45.

IMO the most important finding is(and was on phase 1) that:

Although standards have improved, heat pumps are sensitive to design and commissioning.

It is not clear to me how the non-technical customer ensures that all the MCS guidelines for design and commissioning are met.

Provided a customer gets a 'good' system fitted, and with the generous RHI payments for 7 years(huge for a GSHP), a heat pump must be an alternative to be considered for those without mains gas.

Silent_Dancer

Cardew wrote: »

Thanks for this report.

Anyone contemplating a heat pump should read it thoroughly; in particular the 'advice to consumers'

The main conclusion of Phase 2 of the trial is that 'they' are doing better. It seems the term COP has now been replaced by the more appropriate SPF(System Performance Factor). albeit 3 definitions of SPF

For the Phase 2 trial the average SPF was 2.45.

IMO the most important finding is(and was on phase 1) that:


It is not clear to me how the non-technical customer ensures that all the MCS guidelines for design and commissioning are met.

Provided a customer gets a 'good' system fitted, and with the generous RHI payments for 7 years(huge for a GSHP), a heat pump must be an alternative to be considered for those without mains gas.

It should be noted to achieve the improvements that work was required in some cases replacement of the heat pump with a new larger sized one.

For Phase II of the trial, 38 of the heat pumps from Phase I were selected for a range of interventions, from major (for example, re-sizing the heat pump) to minor (for example altering control parameters). Six new heat pumps, sized and designed according to the new MCS MIS 3005 Issue 3.1 standards, were also monitored.

Anyone considering the RHI in relation to heat pumps (or biomass) should note the following.
1) Energy efficiency measures need to be undertaken first as per a green deal assessment. This is likely to be improved insulation.

2) The payment is based on a deemed energy usage from the EPC after the insulation measures have been taken. Note that this assessment frequently under estimates energy consumption.

3) Metering requirements. All installations must be ready to take a heat meter. You can opt to have the installation meter and you will receive an additional compensation of £230 for additional cost involved. However, in such circumstances you do not gain anything if the your heat useage exceeds the payment as it is capped to the deemed useage level to avoid "overuse of heat"! Note metering is compulsory for 2nd homes and hybrid systems.

More info here
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/212089/Domestic_RHI_policy_statement.pdf

Cardew

Silent_Dancer wrote: »

It should be noted to achieve the improvements that work was required in some cases replacement of the heat pump with a new larger sized one.

Thanks for the above; particularly about the RHI.

That quote above perfectly demonstrates why I started this thread some two and a half years ago.

Even now after minor and major alterations to existing heat pumps in the trial and new installations which you can bet were very carefully selected and installed to the latest MCS standards, the overall SPF(system COP in old speak) was 2.45.

Thousands of ASHPs have been fitted and it is a fair bet that the SPF(COP) for many are way below that figure. Don't forget that several in the phase 1 trial were between 1.2 and 1.6; so it is certain that many existing systems will be in that range.

That is a far cry from the Manufacturer's claims of at least 3.5 units of heat for 1 unit input.

So what will happen to those old systems, often in totally unsuitable houses, with poor performance? The answer will be nothing and other than sky high bills the occupants have no way of quantifying the SPF(COP).

I have no doubt that a properly installed system, in a suitable house, with occupants who understand how to operate it, will give satisfactory results.

However what actions are being taken by the manufacturers to ensure the above criteria are met?

Frankly simply ensuring that the installers are MCS registered is meaningless, unless there is some inspection of the system and their standards.

If an occupant of an unsuitable house contacts a ASHP installer, how many will refuse the job?

I had a fairly large extension on my house recently. I had to pay for the Council building control officers to monitor each stage of construction, after they approved the initial plans. We need something like this for heat pumps.

John_Pierpoint

Back in the mid 1970s, when the European economy was hit by the global oil shock, engineered by OPEC here in the UK, we were rescued by the lucky chance of North Sea gas.
Another country with a good refrigeration industry tried to jump down the heat pump route. That was Austria. I doubt there are many of those early system failures still in use.

I think the Dames probably did the best job in Europe of mastering the balance of heating technologies. I remember a TV documentary about the Danish proposals to introduce the equivalent of 10 inches of fibre insulation into its housing stock in the 19070s - it has stuck in my mind because the English standard was then 3 inches.

Relatively high tech computer controlled heating requires training and experience that I feel will be difficult to achieve in Britain's construction industry with its "labour only subcontract" heritage.

scheissefuergehirn

I had an ASHP installed last July and I am unimpressed with the performance and complexity of the system. The pump is noisy and runs almost continuously when the temperature is around freezing. I doubt that it could handle temperatures of minus 15. I turned the settings down to 10 degrees C recently when I had a one week holiday but the system keeps the water temperature at 30 degrees C to "protect itself" It took one hour for the system to stop trying to heat the house to 21 degrees C. It will use far more electricity than the company estimated but it is probably still cheaper than the oil that I would have used. The RHI will cover almost all of the £7,500 it cost me to install but I still wouldn't recommend an ASHP system to anyone.