Deleted

chris_n

Karmacat said:

One thing that's a possibility is a heat pump?  Air source (cheaper, bit less efficient) or ground source (upends the house and garden for weeks).  Air source might be good enough, as you're not looking to provide for all your needs, just that "gap".

Need more generation then though.

Karmacat

chris_n said:

Karmacat said:

One thing that's a possibility is a heat pump?  Air source (cheaper, bit less efficient) or ground source (upends the house and garden for weeks).  Air source might be good enough, as you're not looking to provide for all your needs, just that "gap".

Need more generation then though.

I don't understand the point you're making, sorry - isn't a heat pump passively collecting energy from air/ground/whatever?  It's doing the generation itself, surely?  Might need a battery/storage device, though!  I'm very non-tech, just very interested.

chris_n

Karmacat said:

chris_n said:

Karmacat said:

One thing that's a possibility is a heat pump?  Air source (cheaper, bit less efficient) or ground source (upends the house and garden for weeks).  Air source might be good enough, as you're not looking to provide for all your needs, just that "gap".

Need more generation then though.

I don't understand the point you're making, sorry - isn't a heat pump passively collecting energy from air/ground/whatever?  It's doing the generation itself, surely?  Might need a battery/storage device, though!  I'm very non-tech, just very interested.

The heat pump requires electricity to run it, it is effectively a fridge in reverse, it certainly isn't passive. Yes you get a multiplication of the electrical energy in (maybe 3:1, maybe 4:1) but you still need to power it. Scarter isn't using electricity to heat her house so would definitely need more generation to provide heat with a heat pump.

Screwdriva

chris_n said:

The heat pump requires electricity to run it, it is effectively a fridge in reverse, it certainly isn't passive. Yes you get a multiplication of the electrical energy in (maybe 3:1, maybe 4:1) but you still need to power it. Scarter isn't using electricity to heat her house so would definitely need more generation to provide heat with a heat pump.

It is impossible to run a ground source heat pump (air source would be lower SCOP and wouldn't work as well in Scotland) off-grid without a ~20kWh battery bank (assuming good insulation, oversized heat emitters, south facing unshaded land that absorbs radiation). It is impossible to recharge a large battery bank without a turbine spinning (wind or water). 

Karmacat

Deleted_User said:

Screwdriva said:

They were built two years ago and all have ground heat source pumps. They're truly stunning houses - lovely architecture for new houses and good build quality. This is why I paid so much attention to them. Anyway, after the first winter almost every one of them had a shiny new woodburner chimney! So I'm assuming the ground heat source pumps aren't up to the job. It's not even that cold where we are - we're close to the coast so it never gets too hot or too cold here. 

That's good information 😲

zeupater

Deleted_User said:

Screwdriva said:

chris_n said:

The heat pump requires electricity to run it, it is effectively a fridge in reverse, it certainly isn't passive. Yes you get a multiplication of the electrical energy in (maybe 3:1, maybe 4:1) but you still need to power it. Scarter isn't using electricity to heat her house so would definitely need more generation to provide heat with a heat pump.

It is impossible to run a ground source heat pump (air source would be lower SCOP and wouldn't work as well in Scotland) off-grid without a ~20kWh battery bank (assuming good insulation, oversized heat emitters, south facing unshaded land that absorbs radiation). It is impossible to recharge a large battery bank without a turbine spinning (wind or water). 

The only knowledge I have of ground source heat pumps in Scotland is in relation to some new build houses a few miles from our home - it's on the route of one of our dog walks.

They were built two years ago and all have ground heat source pumps. They're truly stunning houses - lovely architecture for new houses and good build quality. This is why I paid so much attention to them. Anyway, after the first winter almost every one of them had a shiny new woodburner chimney! So I'm assuming the ground heat source pumps aren't up to the job. It's not even that cold where we are - we're close to the coast so it never gets too hot or too cold here. 

Hi

Are they GSHP or ASHP? .... strange for a developer to go to all the expense and project complexity of the GS loops when they could just get a tradesman in to install an AS unit ... I suppose that if it is a development with GSHPs then the loops will be vertical in boreholes as most gardens are too small for trenched coils ... 

Anyway, heatpump here has been providing almost all of the heating so far this year, most of it's energy coming from solar too ... just one day using the log burner so far & a total of somewhere around 40kWh of gas to top up the DHW and test/bleed the radiators since last Winter ...

HTH - Z

70sbudgie

I did a quick search on domestic / biomass CHPs. Although it seems the technology is available for both, you can't have them at the same time. Biomass CHP seemed to have a minimum electrical output of 20kWe and a thermal output of about 50kWth and they apparently need to run continuously for optimal efficiency (I saw 8000 hours). 

Where as domestic scale CHP seem to be ff (gas) or fuel cell. I guess hydrogen fuel cells might be the future? 

ispookie666

Might be cheaper to get HVO in my oil tank. 
On another note - used 2.5Kwh to heat a large living room for 4 hrs using a A2A Mitsu (7.1kw) to a toasty 21 C.  I have found Mitsubishi to be very good at sticking to the temperature set unlike Daikin, which always overshoots by a few Degrees

Pile_o_stone

I like the look of this 'Ground Fridge'. https://www.groundfridge.com/

I'd be more inclined to look at building a root cellar as it's quite pricey, but I guess there will be no damp or vermin problems with this. I'd also look at fitting a Qooker type hot tap for boiling water - much better to have a low level electrical charge heating water in a vacuum chamber than the 3kw blast of a kettle boiling.

Though if I bought one of these wood fuled cookers, then maybe I'd just boil water on the hob. https://www.stovesareus.co.uk/cooking/range-cookers/wood-burning-range-cookers.html?page=1

70sbudgie

Pile_o_stone said:

I like the look of this 'Ground Fridge'. https://www.groundfridge.com/

I'd be more inclined to look at building a root cellar as it's quite pricey, but I guess there will be no damp or vermin problems with this. I'd also look at fitting a Qooker type hot tap for boiling water - much better to have a low level electrical charge heating water in a vacuum chamber than the 3kw blast of a kettle boiling.

Though if I bought one of these wood fuled cookers, then maybe I'd just boil water on the hob. https://www.stovesareus.co.uk/cooking/range-cookers/wood-burning-range-cookers.html?page=1

I think the ground fridge is what I saw previously.

Looking at the woodburning cook stoves is fun. It seems strange how much the old fashioned range cooker has basically had a face lift! It makes me wonder if I can do anything with our flat topped multifuel burner (that I'm not sure we've ever burned anything other than wood in). What does a cook plate on top of the woodburner actually do to make it more suitable for cooking? Is it something that could be retrofitted? What would be the reasons not to do it?