ASHP – Should do better - Must Do Better

Cardew

Interesting report on the possible future for ASHPs

https://skydrive.live.com/?cid=351450ced12884a5&resid=351450CED12884A5!173&id=351450CED12884A5!173

Even bearing in mind that the report has been commissioned by the industry, it accepts that the present situation with heat pumps leaves much room for improvement - and of course is touting for subsidies.

John_Pierpoint

Excellent find - I have spent all night reading the report and will try to make a few comments over the weekend.

Peterg

I have oil fired CH with radiators fed by a microbore system and would like to change to an ASHP using the existing system as it is.
Everybody tells me that it will not work, but nobody can tell me why !!!
Is there anyone out there who can give me a logical reason why the microbore is not suitable for ASHP when it works perfectly on oil ?
Would it work as a 'Hybrid' system using the boiler to cope with the low temperatures in winter ?

[Deleted User]

Peterg wrote: »

I have oil fired CH with radiators fed by a microbore system and would like to change to an ASHP using the existing system as it is.
Everybody tells me that it will not work, but nobody can tell me why !!!
Is there anyone out there who can give me a logical reason why the microbore is not suitable for ASHP when it works perfectly on oil ?
Would it work as a 'Hybrid' system using the boiler to cope with the low temperatures in winter ?

Correct it will not work efficiently. ASHP/GSHP requires a much faster flow rate, not only that the pipes should also be insulated.

Depending on model ASHPs can work as low as -25c so why bother with the extra costs/maintenance of a hybrid system?

ASHP install must be will planned and executed or it will not be efficient i.e. cheap bills

Peterg

Thanks Jeepjunkie,
Each rad. is individually fed with 8mm from a central manifold and would not a circulating pump with a high head prove suitable ? The reason for considering a 'Hybrid' system is that I have a quantity of oil and the boiler is still performing well.

Andy_WSM

Peterg wrote: »

Thanks Jeepjunkie,
Each rad. is individually fed with 8mm from a central manifold and would not a circulating pump with a high head prove suitable ? The reason for considering a 'Hybrid' system is that I have a quantity of oil and the boiler is still performing well.

I have a Trianco heat pump which is a few years old now and works exactly as you describe. 8mm microbore to a central manifold.

[Deleted User]

Suggest looking through the tech specs for your chosen ASHP. There you should find what is required.

Certainly is for our ASHP.

lardconcepts

Oh dear...

http://www.bbc.co.uk/news/business-19511637

Families living in new government-funded affordable housing have told BBC's Rip Off Britain the heating system used in their homes is costing up to four times more than expected.

The "exhaust air source heat pump" works by taking the heat from waste air leaving the house and pumping it back in to provide heating and hot water.

See whole episode here: http://www.bbc.co.uk/programmes/b01mrhgl

I just heard this being discussed on "You and Yours" today on Radio 4 (should be available later) and some families were paying £10 PER DAY in electricity.

Clearly, they've wrong wrongly specced and badly installed. We have a NIBE Air Source Heat Pump and it HAS saved us a lot, and once we've got a year of data at the end of Sept 2012, I'm going to post all the stats, weekly average external temperature and electricity readings and bills as well as our installation experience.

BUT - it was a long road to get an install that satisfied us; we were pitched many totally unsuitable systems, and if I hadn't once been an HVAC engineer and had taken a lot of interest in how these things work, I'm quite sure we'd have been ripped off and ended up with large bills. We were even told it was cheaper to run it on "full price" electricity rather than economy 7. Had we actually done that, our bills would have been at least 1/3 higher in the winter.

It seems that these councils and housing associations have taken the same approach as they have with solar, biofuelled buses etc, and thought "ooh, green!" without actually doing any calculations.

I'd like to know more about what systems were installed, how they were specced and used etc. I think we were lucky that we got an install engineer that not only specced it and installed it right, but explained in detail what we needed to know about heat curves and how COP was affected by different temperatures, and also how to adjust the "kick in" point for the aux heater. That way, we could fine-tune it for the first month or so to not only balance comfort and efficiency, but even to work out whether to change our alloted off-peak hours.

That way, we ended up with weekly ASHP>water heating bills of around £10-£15 in an old property. To be paying £10 PER DAY in a modern property suggests an extremely badly specced and installed unit. Shame, it's giving heat pumps an undeserved bad name.

Anyway, stats, charts and bills and full writeup to follow at end of month.

Cardew

lardconcepts wrote: »

I'd like to know more about what systems were installed, how they were specced and used etc. I think we were lucky that we got an install engineer that not only specced it and installed it right, but explained in detail what we needed to know about heat curves and how COP was affected by different temperatures, and also how to adjust the "kick in" point for the aux heater. That way, we could fine-tune it for the first month or so to not only balance comfort and efficiency, but even to work out whether to change our alloted off-peak hours.

Your background is atypical, and you had a battle to get the correct installation and were fed mis-information.

The problem is that Mr and Mrs Average don't have the background to understand, don't want to understand, and nor should they have to understand, about heat curves, fine tuning etc.

The Energy Saving Trust 12 month trial of heat pumps pointed out that many customers were confused by the operating instructions; even for standard ASHP and GSHP systems - let alone the exhaust air systems

This extract backs up what some of us have been saying for years:

Manufacturers NIBE say while they are "concerned to hear about individual cases where consumers are unhappy", they believe problems are "almost always due to poor specification, installation or maintenance, and not the systems themselves".

How does Mr and Mrs Average know if the installation will be specified correctly, their house is suitable etc. If you get a firm to quote for an ASHP they are hardly likely to lose a job by telling you that your house is unsuitable. Also the only way you know if the installation is suitable or not is when you get your bills.

You just take 'pot luck' and until the Heat Pump manufacturers take responsibility for their equipment installations, the situation will continue.

lardconcepts

Cardew wrote: »

The problem is that Mr and Mrs Average don't have the background to understand, don't want to understand, and nor should they have to understand, about heat curves, fine tuning etc.

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.