Heat Pumps

[Gasguru]

For ground source a cop of 5-1 should be the norm

You sure?...maybe at the qouted delta T.

I have yet to find any manufacturer willing to quote a realistic seasonal (average) COP....they ALWAYS qoute best case scenario.

Which is why I asked...it is definately not 5 to 1

 

[doitall]

Doitall wrote

Large pipes are considerably more expensive

Yes but the length reduces so the cost is no extra plus the simple connection at the junction manhole is a lot simpler and fast.
How long were you stuck inside that man hole ?.
A week I would guess. Not to mention the malarky with those loops.
Id guess you are looking at £1000 inside that manhole alone.
Compare that with 4 X 40mm T's.
No contest.

And just how long do you suppose theses 4 x 40mm pipes would have to be to give me 56Kw at a COP of 5-1

 

[mehran]

it was a low powered unit, it uses 550watts and give back 2.5 kw back i think. so no fast re-heat times, the guy said it took on average 7 hour to heat from cold to 56'c. the bloke said good for in the day use and back up to temp for the next morning ready for the day.

i guess have a thermostatic mixing valve and have the output temp set at 40 to get some mileage out of it as well

 

[Balenza]

Doitall wrote

And just how long do you suppose theses 4 x 40mm pipes would have to be to give me 56Kw at a COP of 5-1

4 T's Doitall equates to three loops. Three.. !! For a 20kw (output) system.
A slight difference from all that malarky you posted in that last image.

give me 56Kw

Well I would have to guess the refrigerating capacity here as you didn't specify this detail. Either that or get the crystal ball out. 56kw sounds a bit big.
And even if I did know it I would have to start billing you £££ for the information given in the answer to your query.

 

[Agile]

This is all very well but with the average price of electricity at THREE times that of gas you need an average COP of 4:1 to break even with burning gas directly.

The only way you can show any advantage is if you can generate the electricity yourself directly from gas using the waste heat beneficially rather than warming the atmosphere with cooling towers like our power stations.

Tony

 

[doitall]

Doitall wrote

And just how long do you suppose theses 4 x 40mm pipes would have to be to give me 56Kw at a COP of 5-1

4 T's Doitall equates to three loops. Three.. !! For a 20kw (output) system.
A slight difference from all that malarky you posted in that last image.

give me 56Kw

Well I would have to guess the refrigerating capacity here as you didn't specify this detail. Either that or get the crystal ball out. 56kw sounds a bit big.
And even if I did know it I would have to start billing you £££ for the information given in the answer to your query.

Sounds a bit big It's a ferking great country house its also on shale/cotswold stone.

Instead of talking Drivel/Ballski/Watersytem/salesman stick to what you know Exloding cylinder

So we now have 3 loops, how long do they need to be, in stony ground with poor heat properties. lets say we use Ethylene Glycol at 20%.

The design heat required is 56Kw, and to answer an earlier question most of the house is Radiators, so we will need to spec it at 65c.

The nearest 100m will do

As for size/cost, the Germans suppy all the hardware and technical backup.

 

[Balenza]

Doitall wrote

its also on shale/cotswold stone.

Sounds like your company salesman has done a good job.

so we will need to spec it at 65c.

Oops there goes the 5:1 cop down the drain.

 

[doitall]

Oops there goes the 5:1 cop down the drain.

Instead of making stupid comments why can't you answer the question.

5-1 is what its designed for and 5-1 is what it will achieve.

And Our heat pump is more than capable of providing 65c, without any loss to the COP

 

[Gasguru]

So who can tell me the SEASONAL COP, say for double spaced coil underfloor setup (ie the best setup) and conventional rads (ie not oversized and the worst setup)

Doesn't matter how many times I've asked this question on this forum and to heat pump manufacturers they just will not answer....all they ever quote is best case COPs....unachievable for much of the time.

Heat pumps are excellent in Scandinavia and Northern Germany (where nearly all electricity is generated from hydro plants) but in this country they are nothing but a scam. (and actually worse for the environment in many cases).

 

[doitall]

I can agree with what you say gasguru to the point whereas idiots like drivel are chucking a few M's of pipe in the ground with little or no idea what they are doing.

What you have to realise is whatever you take out has to be recoverable by the elements.

If you can extract 12c through the walls of the collector loops throughout the heating season then a COP of 5-1 is easy with the right kit, to do that you need an area approximately twice that of the property of open ground that is shade and tree free.

Electricity is still the greenest fuel in this Country, and will improve if we ever get to build a few nuclear power stations.

The point of renewable energy is you are not burning fossil fuels which will only get more expensive as they run out. I actually tried to work out how much I would save in hard cash compared to Gas, and came up with Zero, but my carbon footprint as Bliar calls it, improves dramatically.

 

[Gasguru]

Electricity is still the greenest fuel in this Country

Carp...the majority of electrical energy generation in this country is not green at all. Its generation results in an appalling waste of energy and should be reserved purely to power non heat producing products.

We are completely the opposite to Scandinavia (where heat pumps are ideal). Most of our electricity comes from burning gas and oil at very low efficiencies (35% at best) wasting vast amounts of energy. By the time customers have shelled out a fortune on heat pumps they aren't inclined to buy the very limited "green" electrical energy at a somewhat higher unit price.



For many larger heat pump installations where a natural gas supply is available then mCHP is a far superior solution over heat pumps.

Heat pumps are pushed by the manufacturers for the simple reason of high profit margins, their green credentials suck. Still we can't have common sense and scientific evidence getting in the way of the unethical heating industry.

 

[simond]

Thank you all for your comments, I will take you up on your offer, DIA.

I agree that the heat pump concept in the UK is somewhat flawed. I guess most of us want to do something positive, and I suppose it all boils down to whether electricity is considered to be grossly polluting and wasteful. I can see both sides of the argument but would not want to turn away a well intentioned request from a customer. After all, they may, in time, turn out to be right!

Many councils are demanding 'sustainable' heating systems as a carrot to give planning permission. Heat pumps are considered very favourably by our politicians, which were apparently all democratically elected. With the possible exception of our Prime Minister

Thanks again,

 

[Balenza]

Here is a more realistic installation. The loops connected to this are 3x200M .
Installation completed in one day by one operative.

 

[Balenza]

Here is an image of the HW system heat pump hooked up to a 300L UV cylinder.
Its totally separate from the main heat pump and uses the return from the ground floor UF heating as the energy collector.
This is a Hautec system.
http://www.english.hautec.net/warm_wasser.htm

 

[Agile]

Many councils are demanding 'sustainable' heating systems as a carrot to give planning permission. Heat pumps are considered very favourably by our politicians, which were apparently all democratically elected. With the possible exception of our Prime Minister

Thanks again,

That shows just how little the politicians really understand about technology!

In Scandinavia where most electricity is water turbine and totally sustainable then heat pumps are fine.

In the UK only 17% of our electricity is from nuclear, wind and water and that means 83% is from burning dirty oil, gas and a bit of coal. Thats at an efficiency of less than 35% !

So unless you have your own wind farm, heat pumps are definately not green at all.

Tony