Heat Pumps, One for the engineers

[mickthemaverick]

The nail in the coffin is the very last paragraph.

More than one coffin nailed there Dave, I'm with you!!

[Dormouse]

I have looked at several Manufacturers and this interesting graph came up for European Markets.

Notice the blue line which is the closest to a domestic water CH system with radiators. It never reaches 3.3 COP. So, not only won't this particular ATW heat pump work efficiently on a wet CH system (only 55`C ) it will never match the COP needed to break even let alone offer savings

[Dormouse]

Just for fun, here is the average outside temperatures this month in Fife

Only on fleeting times this month would the COP of the Orange Line ( underfloor heating ) reach anything close to 3.3 COP and above needed to break even in cost/save money.

Eventually I will badger this Market Harborough firm into giving me a quote for a system for my house ( though I am not going to hold my breath ) so I can see how much money I have to spend to "save" money.

[Dormouse]

When you make enquiries about Heat Pumps to Councils in Scotland it is pointed out that you may require Planning Permission

It is also recommended that existing CH Radiators may be out by about 30% capacity.

The more you research, the more questions need to be answered.

[CitroJim]

That's me resolved not to go down the heat pump route when I have my heating system renewed then...

This is a most interesting and enlightening thread... Thanks all

[Peter.N.]

Yep, that all sounds about right.

Peter

[Dormouse]

Further research into the Heat Loss calculations for the figures quoted earlier are for a R value of 20 for walls - that is 8" of sealed PU Foam plus the structure to support it inside and out!
A brickwork leaf with 4" insulation and plaster inner liner has a R value of around 10 (depending on exact construction ).
The calculations also assume a ceiling ( loft ) insulation rating of 40 - that is 16 to 20 inches of loft insulation.

The build standards of housing in the UK are nowhere near these figures so, unless starting with a complete new build, heat losses are not going to be optimal - for any system.

Good insulation seems to be the key - with any system.

[mickthemaverick]

I can endorse that last statement without any reservations. Up until 2013 we had the usually accepted 8" of loft insulation. In that year my company had a contract to insulate the loft of a nursery school in Willesden. We completed the work with 9 rolls of 9" insulation left over. Yes I did give the project manager a rollicking, but nevertheless as we had no spare storage in the warehouse I brought them home and covered our loft with a second layer giving us 17" in total. What a difference!! Within days I went round the house lowering thermostats and turned the boiler down to 60 where it has remained ever since. As I type this all our radiators are set on number 1, it is currently 2 degrees outside and 21 degrees indoors. Insulate as much as you can but remember to maintain controlled ventilation too.

[Dormouse]

When we designed and built our new home nearly 30 years ago, it had 6" insulation in the walls, a foamed concrete insulated sub floor ( to allow for floor heating coils ) and 10" rafters with 8" of insulation ( 2" for controlled roof ventilation) and extra insulation in the ceilings. Our Architect steered us towards Electric Heating ( glorified Storage Heating ) despite us obviously designing our house with other options in mind including a cast insitu footing for a chimney and fireplace. We had to employ an Architect and a Structural Engineer to sign off on our designs and plans submitted to the Council.

Within a year (two winters ) we junked the All Electric for LPG - could have gone Oil as we lived in a predominately Farming location.

With hindsight we should have gone Underfloor Heating and not have been swayed by a blinkered "Expert".

[Hell Razor5543]

With hindsight we should have gone Underfloor Heating and not have been swayed by a blinkered "Expert".

I recalled a dialogue from Gordon R. Dicksons' book 'Tactics of Mistake'.

"You must believe in yourself as a military expert, Colonel", said deCastries.

"But I'm not an expert", said Cletus. "I'm a scholar. There's a difference. An expert's a man who knows a great deal about his subject. A scholar's someone who knows all there is that's available to be known about it".

Your expert may have know a lot about his subject, but was either not aware of ALL of the information available, or chose not to keep himself up-to-date with that information.

[mickthemaverick]

I think you may get a yellow card for that comment James on the basis that it is far too intellectual for this time on a Friday night!!

[Hell Razor5543]

I think you may get a yellow card for that comment James on the basis that it is far too intellectual for this time on a Friday night!!

But, for me, it is NOT a Friday, it is a Tuesday. My working week goes from Thursday to Monday, and I have Tuesday and Wednesday off, so THAT is my weekend.

[mickthemaverick]

In rhat case James any chance you can join us on Tuesday for lunch as per the turntables thread?

[Hell Razor5543]

I will have to ask Michel if he can give me a lift. While my C5 is on the road I am getting a nasty noise from the right rear wheel, which I believe is down to the rear arm bearing. I will be getting it sorted out (hopefully she is booked in mid Feb), but I would rather not stress the bearings if I can avoid it.

[mickthemaverick]

He hasn't committed yet but if you can let me know to alter the booking it would be good