ASHP – Should do better - Must Do Better

albyota

I have to confess that when air to water heat pumps first started to appear in the UK, I was very sceptical of the technology, even though I had been installing Air con for 4 years prior to 2008, and after investigating, researching, calculating, heat loss, heat load, U values, building fabrics, thermal mass, thermal bridging, insulation, vapour barriers, energy efficiency, heating systems, hydronics, laws of thermodynamics etc...etc...I ran the risk of removing a perfectly reliable 2 yr old oil fired Worcester Bosch Greenstar 18 /22 condensing boiler and fitting the 8.5 kW heat pump, asking other experienced heating engineers for their thoughts.....'that'll never work mate'....and......'your mad....keep the oil boiler'.
I now use on average 10,900 kWh/yr of electricity, 2010 total house running cost. £933

Yes, I agree with cardew, ASHP's should do better and be specified by qualified MCS certified installers/ heating engineers and the manufacturers MUST DO BETTER too.

Cardew

Geotherm wrote: »

I think that you have to look at all in perspective. If the system that albyota has installed, plus in many other houses and these are all working well, then you cannot take all ashps as being troublesome. Why only depend on the EST figures, even they say they need longer confirmation.

I am an engineer and what has concerned me most about ASHPs is the absolute lack of any detailed data on how they perform in real life situations - especially the defrost cycles.

The manufacturers figures are just theoretical nonsense.

All of the 'enthusiasts' figures I have seen are just like Albyota's - the last year I spent £x with oil and this year £y with an ASHP - well that ain't scientific enough for me!

Now along comes the first independant field trial of 19 ASHPs, with management involvement(Mitsubish Daiken etc) and a raft of technical consulltants.

Even with all that technical expertise over a 12 month period, the results were a disaster!

They don't say they need longer confirmation, they say they need investigation why there were poor results.

Now you can hardly ask me to take as gospel an internet forum post by an installer that he has installed 60 systems without problems,(how would he know) and ignore a controlled trial where the manufacturers can't get them to work properly. I am not disputing Albyotas own figures.

All over the internet , including MSE people are reporting horror stories about their systems, unable to cope with severe weather and huge electricity bills - why would they lie?

To repeat myself, people shouldn't have to spend £6,000+ on an ASHP system and gamble that it might work.

It should be mandatory that the manufacturers/installers give a cast iron guarantee on performance.

albyota

To meet the MCS requirements, ASHP manufacturers have to submit their systems for testing, they are all tested by the BRE (British Research Establishment) in Watford to very strict criteria in a strict test environment. It is the BRE that gives the COP rating for the equipment.

lovesgshp

No manufacturer could give a cast iron guarantee on performance, they can only specify to control design and certification. these are set at levels on a norm. Someone who sets temps above that will have higher running costs. A thermal loading of the house should be calculated in all instances for correct sizing. If that is not done,then its guesstimate.
I agree no-one should spend 6k on a system that underperforms. We have people here spending Euro 20k+ on gshps that are totally happy with performance and the low running costs, even against what they were paying in the UK.
Recommended temperatures for a room with underfloor heating is 19C, although systems are specified at 20C for output. If you raise the temp to 21-22,then your energy cost increases. I use in total under 10000Kw per year, with the heating at 19c. I have a gshp, which is more efficient than an ashp, but am not in a highly insulated house.

albyota

Cardew wrote: »

Now you can hardly ask me to take as gospel an internet forum post by an installer that he has installed 60 systems without problems,(how would he know)

Believe me cardew, I would know straight away, they all have my phone number, phone is always switched on, if there were problems, we would have an engineer on site within a couple of hours, plus phone assistance, we have had problems with some systems....but its the way they are dealt with that makes the difference.

There are always going to be cowboy installers out there, in every trade, The Gas safe register was set up to eliminate cowboys, but they still continue to operate. same as Part P for electricians.

The bigger, better manufacturers of ASHP's do not want their brand name tarnished so there are accreditation courses for installers with strict qualifying criteria, whereas the smaller companies just boxshift through merchants.

albyota

Incidentally, Mitsubishi alone now have over 6500 installations in place all over the UK, Daikin have about the same, the EST only trialled 29 assorted makes....and that was in 2008 before MCS was in place. come on, compare apples with apples.

rhiwfield

Cardew wrote: »

Now along comes the first independant field trial of 19 ASHPs, with management involvement(Mitsubish Daiken etc) and a raft of technical consulltants.

Cardew, as a potential end user of an ASHP I've read the EST trial results. Could you clarify the extent of involvement please of management and technical consultants to warrant your claim that
"Even with all that technical expertise over a 12 month period, the results were a disaster!"

The daft thing is that I agree broadly with the heading of your original post, but find myself reacting against the stridency of your anti-heat pump rhetoric.

Albyota, I posted before on MSE for advice on a bivalent system but didnt really receive any. The issues that I am not fully happy with re an ASHP are:

• expertise of installers generally, including specification and sizing of system
• COP at low temperatures (hence considering bivalent system)
• reliability of heat output at low temperatures

If we go down this route I'll probably be looking at Daikin or Mistsubishi, current heat requirement for insulated 70's house is prob 16kW but we have supplementary woodburner in main heat requirement room (5kW). It will be an air to water system for space heating only. The existing oil boiler is reliable and 84% efficient, but we will need to resize some rads.

albyota

rhiwfield wrote: »

Albyota, I posted before on MSE for advice on a bivalent system but didnt really receive any. The issues that I am not fully happy with re an ASHP are:

• expertise of installers generally, including specification and sizing of system
• COP at low temperatures (hence considering bivalent system)
• reliability of heat output at low temperatures

If we go down this route I'll probably be looking at Daikin or Mistsubishi, current heat requirement for insulated 70's house is prob 16kW but we have supplementary woodburner in main heat requirement room (5kW). It will be an air to water system for space heating only. The existing oil boiler is reliable and 84% efficient, but we will need to resize some rads.

rhiwfield, expertise of installer should be sought like any other major investment, either from word of mouth or by recommendation, or from the MCS database, or on the 'find an installer' part of the manufacturers website. Look for a company that doesn't just specify one brand.

The COP of any of the equipment will be annual COP at x external temp and x water temp. Temperature curve charts can be very useful if you can get these for each system you are considering. If it is connected as a bivalent system, it is quite easy to monitor at what ambient temperature the system becomes equal in cost/kWh to the standby boiler.
It is strongly recommended that the radiators be upgraded by at least 30%.

Not sure how the proposed RHI will calculate for bivalent systems, probably reduced by the percentage of the house heated by the heat pump.....

Cardew

rhiwfield wrote: »

Cardew, as a potential end user of an ASHP I've read the EST trial results. Could you clarify the extent of involvement please of management and technical consultants to warrant your claim that
"Even with all that technical expertise over a 12 month period, the results were a disaster!"

The daft thing is that I agree broadly with the heading of your original post, but find myself reacting against the stridency of your anti-heat pump rhetoric.

Albyota, I posted before on MSE for advice on a bivalent system but didnt really receive any. The issues that I am not fully happy with re an ASHP are:

• expertise of installers generally, including specification and sizing of system
• COP at low temperatures (hence considering bivalent system)
• reliability of heat output at low temperatures

If we go down this route I'll probably be looking at Daikin or Mistsubishi, current heat requirement for insulated 70's house is prob 16kW but we have supplementary woodburner in main heat requirement room (5kW). It will be an air to water system for space heating only. The existing oil boiler is reliable and 84% efficient, but we will need to resize some rads.

On your first point, about manufacturers and technical consultants, this is in the preamble:

The Energy Saving Trust would like to thank our partners, who have made this field trial possible:

Government organisations
The Department of Energy and Climate Change
The North West Regional Development Agency
The Scottish Government

Manufacturers
Baxi Group
Danfoss UK
Mitsubishi Electric
NIBE Energy Systems
Worcester Bosch

Specialist heat pump contractors
Earth Energy Ltd

Energy suppliers
British Gas
EDF Energy
E.ON Engineering UK
NIE Energy
RWE npower
Scottish Power Ltd
Scottish & Southern Energy PLC

Technical consultants
EA Technology Ltd
Energy Monitoring Company
Gastec at CRE Ltd
The Open University

Energy Saving Trust project team:
Simon Green, Project Director
Jaryn Bradford, Project Manager

“The Department of Energy and Climate Change(DECC) is very pleased to support the Energy Saving Trust’s field trials into heat pump technology. Field trials such as these are a
valuable way of establishing true performance in situ, as opposed to in the laboratory, and provide useful insights as to how performance may be improved. This is beneficial for industry, householders and the Government. DECC considers that heat pumps have an important role in achieving Government policies to reduce CO2 emissions”

In keeping with the Energy Saving Trust’s work throughout Europe and the UK, the results of this first year of the trial have been peer-reviewed by leading EU heat pump experts, including the SP Technical Research Institute of Sweden, Planair (Switzerland)
and Germany’s Fraunhofer Institute, as well as UK stakeholders including the Energy Technologies Institute (ETI).

With regard to your second point:

The daft thing is that I agree broadly with the heading of your original post, but find myself reacting against the stridency of your anti-heat pump rhetoric

.

I accept that my posts are not balanced, but it is a reaction to the "get correctly sized pumps fitted by a proper installers and you will be OK" line that is trotted out.

Until recently ASHPs on MSE were trotted out as the fail proof solution to high energy bills. Many advocating even getting rid of Gas CH and that with no gas, ASHP's were a 'no brainer' solution. Frankly as the results of this trial, and lots of examples on the web, demonstrate - they ain't!!

The conclusions of the trial were that research must be carried out on the poorly performing systems to find out the reasons why so many are performing badly, and steps need to be taken to improve matters.

Bear in mind also that the 12 month trial period did not cover last December's exceptionally cold weather.

My point was that with all the expertise listed above, they were not able to pinpoint reasons for the poor performance of many systems.

Likewise, with the many horror stories of badly performing systems, that are unable to cope with last months weather and high electricity bills, it seems the combined efforts of installers and manufacturers have not solved the issues.

We are actively working with the MCS and the heat pump industry to improve the availability of training for heat pump installers, including skills-based training courses. Heat pump standards in North America and Europe contain much guidance that can help the UK market. For example, Denmark and Sweden have EU quality assurance certification schemes for sizing, installation and installers. The Energy Saving Trust will work with the UK government and industry to re-assess appropriate training for installers.

A further problem is it is just not possible for the customer to evaluate the performance of the ASHP system. I have twice phoned Mitsubishi and enquired what could I expect from an Ecodan system for heating and hot water. Each time I was told that it would be 3.5 units of heat for 1 unit of electricity.

Not one ASHP on the trial got near that figure. So if a customer could measure the COP(overall efficiency) - which he can't - and it gave less than 2.0, he has absolutely no come-back.

So the title of this thread is valid - Should do better - must do better - before anyone should gamble £6,000+ on an ASHP in the hope that it works correctly.

grahamc2003

Reading these threads, I think most of most people's posts are interesting and informative. What is missing and probably not getting a fair hearing, are those with systems such as Ecodans who are psoting their experiences here, and who's heating has been both acceotable and reasonable cost. I'd like to see how these have performed over the last few weeks - all we seem to get are those who have had terrible problems (with other systems).

At the moment, the lack of perfectly happy air to water, with full house heating systems leads me to believe they may have fundamental problems in the coldest of UK winters, and for that reason, until more evidence comes along, I certainly wouldn't commit unless I had another system as backup. Having said that, there does seem to be several who are really happy with smaller, standalone air-to-air systems, although I don't recall reading their experiences over the very cold weather. Be great if Steve could post his experiences, to perhaps redress the balance a bit.


Albyota, I'm surprised you don't list the defrosting strategy as an area of concern, since I think ice buildup seems to be a real problem sometimes (and not easily solvable imv by the solutions proposed on here i.e. a small heater, but that's for another thread).