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14 minutes ago, Yellow Bear said:

Incorrect, the point of CHP (and I have been involved in the installation of many) is to generate electricity, the heat if purely not wasting the by product of this generation.

Fair enough, I stand corrected. It was an engineer from EDF who was extolling to me the virtues of Micro CHP boilers in the home and their benefits to our overall Carbon footprint. A Stirling generator captures wasted heat and converts it to electricity, he said.

https://www.thegreenage.co.uk/tech/chp-boilers/ would seem to be at odds with your statement though

"A home would typically use a boiler to meet its heating and hot water needs only, and then source its electricity from the grid. Central generation wastes a significant proportion of the energy it creates, through heat losses in the power station and in the transmission and distribution network.

Micro-CHP boilers avoid these losses, and capture the heat for use within the home. This efficiency can save the consumer around 25% of total energy costs (around £600 off your bill if you have a typical 3-bed semi-detached house), and reduce each home’s CO2 emissions by up to 1.5 tonnes per annum. Micro-CHP boilers are designed to generate all of the heating and hot water and a significant percentage of the electricity needed by a typical UK home."

You and UdderlyOffroad clearly know more than me though, so I'll leave it to you guys to fix the issues of the next few generations :D

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11 hours ago, Jaymo said:

We have recently installed UFH and an ASHP. What can I say except for - how do I get a second mortgage to pay for the running costs.

Am awaiting the RHI scheme to finally acknowledge my application. 
 

The house were currently living in which is on gas. It’s three times the size with half the price for heating. 

And what have you learned from this experience?:w00t:

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The whole broad topic of energy, heating and fuels doesn't have a single 'right' answer.  There is no 'one solution fits all' answer.  In my view the following points are important in making the right decisions;

  1. Insulation, draught proofing, energy conservation are primary considerations.  Where possible, the insulation of a property should be improved as much as reasonably practical consistent with avoiding damp and having adequate ventilation.   This may mean some sort of heat recovery forced ventilation is desirable.  Insulation in older properties needs very careful thought as it can cause all sorts of problems where old walls 'need to breathe'.
  2. Energy costs and system insulation costs are a balance.  Typically - more efficient systems are more expensive.  If the property is well insulated and the overall heat load is small, a higher 'per unit' price may be acceptable.  Conversely - where it is recognised that energy usage will be higher (such as older properties where insulation may be limited and larger properties - it is usually worth spending more on an installation that may be cheaper to run over the years.  Systems such as underfloor are unobtrusive and efficient, but expensive to install 'afterwards' and are at their best in well insulated properties.
  3. Where energy is 'bought in bulk up front' such as oil, solid fuels whether logs, pellets, or coal products, or liquified gas - storage (space, size, safety) are a consideration.  Supplies can be bought at 'cheaper times' if you are lucky.  Piped in real time energy (mains electricity and gas where available) are convenient, but your hands are more tied in costs.  At present gas is relatively cheap, whereas electricity is relatively expensive.  It is also almost certain that 'variable pricing' will come with smart meters.
  4. Things like solar are much dependant on subsidies to make the economics attractive - and these can change with time either way.
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22 minutes ago, TIGHTCHOKE said:

And what have you learned from this experience?

Stick to tradition.....

This way we’re going to have to go ‘hybrid’ with an lpg boiler to give the initial heat boost and ASHP to take over and maintain 

No gas in the village were moving too and oil tank / lpg tank siting is difficult due to the current regs...

ASHP are noisier than you would expect too.

Im sure we will sort out the timings and heat demands and fortunately the RHI will offset the costs to some degree plus a change of tariff is required too. 
In 7 years the RHI will pay for the pump, but that’s no good if it’s running around £340 per month in winter. 
 

To mitigate thermal losses the roof has been refelted using a super quilt breathable insulated blanket. Internally the roof has superquilt multi layer insulation. 270mm of traditional fibre insulation and all external walls have 34mm insulated plasterboard on filled cavity walls.

Only thing we didn’t/couldn’t do, was pull up the concrete slab to insulate- supposedly the UFH downward losses are meant to be minimised. 
 

Edited by Jaymo
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25 minutes ago, Demonic69 said:

A Stirling generator captures wasted heat and converts it to electricity, he said.

Did the engineer mention the efficiency of the Stirling cycle, perchance?  40% is good, in theoretical exercises.  And that's before you consider the mechanical losses due to friction

 

1 hour ago, Demonic69 said:

https://www.thegreenage.co.uk/tech/chp-boilers/ would seem to be at odds with your statement though

You serious?  That website is all marketing waffle, with very few actual numbers, and definitely no sources for their claims! Oh and all the links to CHP boilers are dead?

Ok, let's do this...

1 hour ago, Demonic69 said:

Central generation wastes a significant proportion of the energy it creates, through heat losses in the power station and in the transmission and distribution network.  But the overall efficiency of the process will still be better than millions of CHPs, surely?  What thermodynamics-defying magic have they used to achieve this?

Micro-CHP boilers avoid these losses, They avoid transmission losses, brilliant.  Does it offset the increased carbon emissions or increased energy used?

and capture the heat for use within the home.  Shhh, nobody mention condensing boilers...

This efficiency can save the consumer around 25% of total energy costs (around £600 off your bill if you have a typical 3-bed semi-detached house), Compared to what?

and reduce each home’s CO2 emissions by up to 1.5 tonnes per annum.  By up to?  Are they considering the carbon emissions used to generate the electricity at the powerplant?  What about the carbon emissions associated with getting the gas out of the ground and transporting it to the house?  I could make those numbers look very favourable if I ignored those factors too (see: biomass generation)

Micro-CHP boilers are designed to generate all of the heating and hot water and a significant percentage of the electricity needed by a typical UK home."   A significant percentage??  How much?

 

The case for CHP is weak at best.  And it doesn't wean us off our addiction to gas - albeit they *can* run on other fuels.  There may be some edge cases where it makes sense, in remote areas, but for the vast majority of the suburban UK population...not so much.

 

56 minutes ago, JohnfromUK said:

  There is no 'one solution fits all' answer.  In my view the following points are important in making the right decisions;

Spot on.  Also important to mention that the UK has a terrible attitude to housing and energy efficiency.  Yes, new homes are built to reasonable standards re energy efficiency, and therefore other technologies make sense. 

Nowhere is it written, for instance, that you have to use electric boilers to power radiators.  If you have a modern house, but no mains gas connection, an electric boiler with underfloor heating could be a good solution for you, especially if you have a decent PV installation to supply your base load.  Happens to be how many other nations in Europe do it...

Also, because we're so used to poorly insulated houses with badly-designed heating systems, we in the UK tend to run the central heating incredibly sparingly.  This 'manual control' means we're always fighting thermal inertia.  A well insulated house with a well-designed heating system, and you're far better off letting the heating system run constantly and let it control the temperature.  But that mindset can be hard for the average Brit, raised in drafty-ice box houses to get their head round

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2 minutes ago, udderlyoffroad said:

Did the engineer mention the efficiency of the Stirling cycle, perchance?  40% is good, in theoretical exercises.  And that's before you consider the mechanical losses due to friction

No, we were supposed to be discussing reactor power cycles, but somehow segued onto boilers! He was very passionate mind.

3 minutes ago, udderlyoffroad said:

You serious?  That website is all marketing waffle, with very few actual numbers, and definitely no sources for their claims! Oh and all the links to CHP boilers are dead?

I was trying to update my knowledge and it was one of the first sites I came across 😂

5 minutes ago, udderlyoffroad said:

Central generation wastes a significant proportion of the energy it creates, through heat losses in the power station and in the transmission and distribution network.  But the overall efficiency of the process will still be better than millions of CHPs, surely?  What thermodynamics-defying magic have they used to achieve this?

Micro-CHP boilers avoid these losses, They avoid transmission losses, brilliant.  Does it offset the increased carbon emissions or increased energy used?

and capture the heat for use within the home.  Shhh, nobody mention condensing boilers...

This efficiency can save the consumer around 25% of total energy costs (around £600 off your bill if you have a typical 3-bed semi-detached house), Compared to what?

and reduce each home’s CO2 emissions by up to 1.5 tonnes per annum.  By up to?  Are they considering the carbon emissions used to generate the electricity at the powerplant?  What about the carbon emissions associated with getting the gas out of the ground and transporting it to the house?  I could make those numbers look very favourable if I ignored those factors too (see: biomass generation)

Micro-CHP boilers are designed to generate all of the heating and hot water and a significant percentage of the electricity needed by a typical UK home."   A significant percentage??  How much?

You clearly have a better grasp of this than pretty much anyone else. Have you actually posited viable alternatives that not only save money but are also either more efficient or reduce carbon emissions? Honest question, I'd love to hear a well formulated argument for one type or another for a pretty standard family home as I may need to replace my boiler soon-ish.

 

Cheers

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