The Green Agenda

[drinksloe]

Following on from Big J's post.

 

I looked into various heat pumps and RHI a few years back when i started renovating an old house.

 

Similar to wot J was saying with the domestic RHI tarriff back then ( it may be different now) they gave u an annual grant for ur house depending on size and insulation no matter wot u actually spent/used.

The broad estimates were around 250kw/m2/yr for an old farm house, about 50 kw/m2/yr and as little as 5 kw/m2/yr for a passiv/eco type house.

Thats a massive difference.

 

I have been told that 1 of the potential draw backs with a bore hole type ground source is that in theory in some places over time ur ground source could actually draw too much heat out of the ground immediately round the bore hole as after 10m won't be getting topped up every summer like a looped system would.

Also the pumps do draw some juice when they have to start pumping

[Woodworks]

7 minutes ago, drinksloe said:

Following on from Big J's post.

 

I looked into various heat pumps and RHI a few years back when i started renovating an old house.

 

Similar to wot J was saying with the domestic RHI tarriff back then ( it may be different now) they gave u an annual grant for ur house depending on size and insulation no matter wot u actually spent/used.

The broad estimates were around 250kw/m2/yr for an old farm house, about 50 kw/m2/yr and as little as 5 kw/m2/yr for a passiv/eco type house.

Thats a massive difference.

 

I have been told that 1 of the potential draw backs with a bore hole type ground source is that in theory in some places over time ur ground source could actually draw too much heat out of the ground immediately round the bore hole as after 10m won't be getting topped up every summer like a looped system would.

Also the pumps do draw some juice when they have to start pumping

A system that gets freezing around the pipe has just been badly designed with too small a loop/hole that cant recover quick enough. There were quite a few stories about this in the early days and our ground loop will run below freezing when we work it hard in dry weather in the coldest weather. In hindsight I would have put in a bigger ground loop but it works fine and recovers quickly when the water table comes up just would be more efficient with more pipe

 

Worked out the other day we were 33kw/m2/yr plus around 3 cube of logs. Thats total electric import but we do have PV as well and cant separate that. Old barn but insulated up to regs of around 10 years ago. 

[drinksloe]

Aye i was meaning the vertical bore hole type as it will never be topped up from solar energy like the shallow loops will.

 

But i am sure like a lot of these things a lot were installed badly in the past without full knowledge of wot they were doing.

Really this country is so far behind the times with modern heating ideas and even when we get the idea usually implement/install it very badly not looking at how other countries have done it for decades.

In NZ been installing heat pumps for 30 odd years now.

 

Is it possible to just extend the pipe run/loop after its fitted?

I imagine u could just cut it and join another run of loops on?

[Woodworks]

17 minutes ago, drinksloe said:

Aye i was meaning the vertical bore hole type as it will never be topped up from solar energy like the shallow loops will.

 

But i am sure like a lot of these things a lot were installed badly in the past without full knowledge of wot they were doing.

Really this country is so far behind the times with modern heating ideas and even when we get the idea usually implement/install it very badly not looking at how other countries have done it for decades.

In NZ been installing heat pumps for 30 odd years now.

 

Is it possible to just extend the pipe run/loop after its fitted?

I imagine u could just cut it and join another run of loops on?

I could extend our ground loop but it would be better to have a separate loop back to a manifold as one long loop would add more resistance to the circulation pump. Honestly I dont think its worth the hassle for the small gains. We dont work it hard as in the coldest weather we use the wood-burner and its fine running a touch below freezing anyway just a slightly lower COP. Certainly no problems with ground heave which you get when you have sustained freezing around the pipes.

 

No doubt we are backward country. Still hear people saying 'oh dont trust this new technology' As you say people have been using heat pumps for decades and most homes have one in the homes in the form of a fridge. On top of that there's rip off instal costs when there are  things like the RHI about. Think our costs came in under 4k pre RHI but simple £1200 grant. I was able to self install which will have saved a few bob.

[Mark J]

3 hours ago, Big J said:

The entire green industry in the UK serves to extract grant money and feed in tariffs, with the efficacy and functionality of the systems a second priority. Until technology makes sense without grant assistance, universal adoption won't happen.

 

The thing with things like heat pumps, solar and other forms of microgeneration is that they are relatively easy and cheap to install compared to properly insulating our homes. It's a form of 'green washing' that shows people (and voters) that you care about green issues without actually tackling the underlying, main problem. 

 

With 29 million homes in the UK, the task to bring them to a 21st century standard is unenviable. 

 

Anyway, I've just accepted a quote for air to air heat pump installation on our Sweden home. Mitsubishi units, with up to 7kw of heating or cooling, split across two units. Total installation quote - £3195. Installation cost would at least double here.

It doesn't really look to me like there is a green agenda in England. 
They say what they think will win them money (votes).
 

[Stere]

Quote

Anyway, I've just accepted a quote for air to air heat pump installation on our Sweden home. Mitsubishi units, with up to 7kw of heating or cooling, split across two units. Total installation quote - £3195. Installation cost would at least double here.

 

Will this be with normal rads not underfloor as you said insulation in the house is already good?

 

What sort of COP do you  expect?

[trigger_andy]

Some interesting programmes on R4 yesterday relating to this. Call You and Yours was asking "what are you doing to live in a more environmentally friendly way?" and Costing the Earth was exploring whether it was more environmentally friendly to renovate older buildings or tear them down and build again.
 
Despite it somewhat disagreeing with the conclusions of Costing the Earth, I think in many cases tearing down and starting again is best. Some buildings are simply impossible to bring to a modern standard. If old, inefficient buildings are replaced with modern, timber constructed (ie, sequestering carbon) structures, a vast amount of fuel can be saved heating them.
 
Over the past 14 years of living in old farm cottages/houses in Scotland and Devon, we've burned around about 450 cubic metres of firewood. That's over 200t green weight. You could build a lot of houses out of that.

I don’t agree with is thinking at all.

1, Lose beautiful (eye of the beholder) old buildings that have been build with craftsmanship that simply can’t or won’t be replaced to build some boring rabbit hutch? No thanks.

2, Id put money on 50% of that 200t could not be used in construction. I’d say it could be as much as 90%. You are/where a miller. You know the recoverable amount of timber per log is fairly low. That’s out of sawlogs. I doubt you burned 200t of sawlogs either. What I envision you burned was a far lower grade and only suitable for firewood. With wood being close to as carbon neutral as you can get regardless how much you burned it was still “good for the environment”.

[Woodworks]

1 hour ago, Big J said:

Some interesting programmes on R4 yesterday relating to this. Call You and Yours was asking "what are you doing to live in a more environmentally friendly way?" and Costing the Earth was exploring whether it was more environmentally friendly to renovate older buildings or tear them down and build again.

 

Despite it somewhat disagreeing with the conclusions of Costing the Earth, I think in many cases tearing down and starting again is best. Some buildings are simply impossible to bring to a modern standard. If old, inefficient buildings are replaced with modern, timber constructed (ie, sequestering carbon) structures, a vast amount of fuel can be saved heating them.

 

Over the past 14 years of living in old farm cottages/houses in Scotland and Devon, we've burned around about 450 cubic metres of firewood. That's over 200t green weight. You could build a lot of houses out of that.

Not sure I am with on this one. Most buildings can be insulated either inside or out. We did our 200 year old barn inside and dads 300 year old farmhouse outside. External insulation completely changes the character of a building but it does make it easy to heat and far cheaper than knocking it down and starting again. 

[Woodworks]

1 hour ago, Big J said:

 

The difficulty in internally insulating houses is that you lose interior space. Given that we live in the smallest houses in Europe, that's not really an option for most.

 

External insulation is in a way better (especially if you have a massive stone/brick structure, due to thermal storage and regulation) but very few British houses have decent overhangs on roofs, so a new roof would be required too. 

You dont need overhangs though. Sure its looks better with the eaves covering it but there are trims to work around the problem.

 

This is dads old farmhouse. I slate hung the south wall with insulation behind and its covered by the eaves and he had the other wall professionally insulted with capping trims at the top. It's not pretty but works. The roof will need doing in due course and we can then extend the roof to cover the insulation