Climate change, heat pumps the answer?

[Wisconsonian]

Five pages in and I'm not sure what a Heat pump is?
It seems it not what we call heat pumps in NZ, which are basically just AC units that heat as well. I've 2 in my house plus a log burner.

Heat pumps are AC units that have a reversing valve to provide heating through the refrigeration cycle, HERE. Sounds like most of these are heat only, so an AC unit without a reversing valve, but designed backwards to pull heat from the outdoors and pump it indoors. ASHP, Air Source Heat Pumps work good in mild climates, but have the issue of defrost in wet near freezing conditions, and drop off dramatically in cold weather (can get -40 here where air source heat pumps are mostly air to air so lower temp heat output than air to water, especially for radiators, and even more so for old radiators in old houses). GSHP, Ground Source Heat Pumps are expensive and rely on the installers knowledge because of the ground loop, borehole, water source etc. But GSHP aren't hurt in the COP by the outside temperature, but often need backup heat due to the higher heating demand.

Hard to believe oil is preferred to ASHP in UK, here oil is competitive with resistance electric, if the climate was more suitable ASHP's would be cheaper than Propane, and Natural Gas even. Of course most houses here have hot air furnaces, and not nearly as many listed houses either.

 

[FonterraFarmer]

Five pages in and I'm not sure what a Heat pump is?
It seems it not what we call heat pumps in NZ, which are basically just AC units that heat as well. I've 2 in my house plus a log burner.

I have a heat pump here, there shite , power bill goes through the roof in winter. (pun not intended)
When I get around to building a house I'll be using decent insulation, double glazing and possibly building it like they do in BC on Vancouver Island and with a wood fire, using dry wood especially wattle give very low smoke, maximum heat with a renewable source.
Apart from that the Greens and Labour not like it they can GFT.

 

[bitwrx]

How much does one of these modular nuclear reactors cost? I don't know what that device is or how it works but it looks like a jet engine which is cool.

I think the solution is to have a local molten salt reactor in each town or village and pump hot steam to each house for heating and make electricity from it as well.

No one knows how much a small modular reactor costs, because no one has ever built one. Still very much at the drawing board stage at best.

Likewise, molten salt reactors. Their main issue is that the molten salt is chemically incompatible with the materials typically used in nuclear reactor construction. So they require a whole new materials philosophy, putting them quite some distance from commercial exploitation.

 

[john432]

You don't need water, you sink pipes down in the borehole, the contents of which then recover heat from the surrounding soil. The deeper you go, the more warmth can be recovered, and the less the surrounding soil will be cooled.

Warmth? In Wales? Yes this is Wales not Iceland.

 

[Mr Mackay]

I was thinking about having a pipe from Iceland ,to bring all that hot water

 

[Exfarmer]

Heat pumps are AC units that have a reversing valve to provide heating through the refrigeration cycle, HERE. Sounds like most of these are heat only, so an AC unit without a reversing valve, but designed backwards to pull heat from the outdoors and pump it indoors. ASHP, Air Source Heat Pumps work good in mild climates, but have the issue of defrost in wet near freezing conditions, and drop off dramatically in cold weather (can get -40 here where air source heat pumps are mostly air to air so lower temp heat output than air to water, especially for radiators, and even more so for old radiators in old houses). GSHP, Ground Source Heat Pumps are expensive and rely on the installers knowledge because of the ground loop, borehole, water source etc. But GSHP aren't hurt in the COP by the outside temperature, but often need backup heat due to the higher heating demand.

Hard to believe oil is preferred to ASHP in UK, here oil is competitive with resistance electric, if the climate was more suitable ASHP's would be cheaper than Propane, and Natural Gas even. Of course most houses here have hot air furnaces, and not nearly as many listed houses either.

The problem here in the UK is we can get prolonged periods of cool 0 - 5degrees with very high humidity in our Winter period. We very rarely get prolonged spells of continuous freezing conditions. It is this cool foggy weather which is the real killer for heat pumps as they have to go into reverse cycle continuously to keep the fins clear. Today the weather has got couple ofdegrees warmer but especially, humidity has dropped and the pump is running fine

 

[Mr Mackay]

The problem here in the UK is we can get prolonged periods of cool 0 - 5degrees with very high humidity in our Winter period. We very rarely get prolonged spells of continuous freezing conditions. It is this cool foggy weather which is the real killer for heat pumps as they have to go into reverse cycle continuously to keep the fins clear. Today the weather has got couple ofdegrees warmer but especially, humidity has dropped and the pump is running fine

Thats really interesting !! Didnt realise that !

 

[Exfarmer]

Thats really interesting !! Didnt realise that !

I was replying to our American friend, who obviously believes the UK is a land where the sun does not stop shining!
Just worked out I spent £19.75 pence on electric yesterday, mostly keeping the heat pump going. Very little solar off my roof yesterday as it was dull and misty nearly all day. Today looks a lot better though! Sun has just come out

 

[aidan]

I ain't no expert on them but I do have a ground source heat pump installed and it's coming up to 5 years running. Never had the monthly cop drop below 3.5 that I can remember but that was a March that had 20 odd nights of minus temps, it usually always averages in the 4's.
Attached images taken 10 mins ago showing usage so far this month and the rolling 12 month average. No immersion backup installed altho the wiring is there if needed. 12kw pump but runs at 50% capacity or less most of time unless temps drop into minuses and it will ramp up to 75-80% capacity.
Running on night time rates 95% of the time but can run daytime if needed, it is heating a 2500sqft (built 2016) house at a constant 18 (upstairs) to 20 degrees (downstairs) for approx 600euro a year.
As someone says u will never have a 'hot' house, but underfloor is a different type of heat, on a cold day you will hit what feels like a wall of heat when u walk in but the stat in the back hall will be reading 19 degrees and after 2mins it will feel normal.
I'm very happy with the setup, my only niggle is the reliance on electric for all heating!, would love to get my hands on a genny that could comfortably run it if ever needed cos if there is ever going to be a prolonged power outage u just know its going to be because its middle of winter and there is 2 foot of snow on the ground and repair crews can't get out! Pto genny on back of tractor for couple hours a day would keep things right!!
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what model you got there, and are you able to give us a quick overview of the amount of insulation you have in the house

 

[neilo]

Warmth? In Wales? Yes this is Wales not Iceland.

Yes, the soil is warm (even here), with more warmth the deeper you go.

Don’t drill too deep though, or we’ll have an Icelandic volcano popping up in Wales!

 

[john432]

Yes, the soil is warm (even here), with more warmth the deeper you go.

Don’t drill too deep though, or we’ll have an Icelandic volcano popping up in Wales!

I stand to be corrected...we do have a hot spring in Wales..20degee Centigrade..too cold for my bath water.. so I'll just have to keep burning the logs.

Taff's Well Thermal Spring - Wikipedia

en.m.wikipedia.org

 

[neilo]

I stand to be corrected...we do have a hot spring in Wales..20degee Centigrade..too cold for my bath water.. so I'll just have to keep burning the logs.

Taff's Well Thermal Spring - Wikipedia

en.m.wikipedia.org

Iirc soil temp is relatively constant at around 10 degrees if you go 2m down? The GSHP works by extracting that heat, the same as a fridge or a/c unit in reverse.

Your log burner will have a considerably lower capital cost, with lower running costs and, arguably, a lower carbon footprint.

 

[john432]

I would say that it works by dumping the cold outside side the house. Same but opposite principal to a fridge or freezer..their best placed in a cooler utility room, or even out in the garage. Not next to the Rayburn or aga in the Kitchen.

 

[24/7 farming]

what model you got there, and are you able to give us a quick overview of the amount of insulation you have in the house

It's a 12kw ecoforest heat pump and is fed by 650m of ground source piping (not slinky) buried at 4-5ft deep and pipes min 4-5ft apart.
House is about 250sqm over 2 floors and has 150mm solid insulation in the ground floor with 80mm concrete screed over the pipes. Walls have 200mm cavity with pumped insulation and 150mm solid concrete blockwork interior wall, also 50mm insulation between all walls and floors, standard apex roof with 400mm earthwool insulation. Triple glazed passive windows. All junctions and joints taped with air tightness tape before plastering (a seriously under rated procedure in this part of world) . Backed up with MVHR system.
Heat pump is also installed within the heat envelope of the house

 

[2wheels]

as i have said before try carbon neutral energy aberdeen. carbonneutralenergyltd.com

 

[aidan]

It's a 12kw ecoforest heat pump and is fed by 650m of ground source piping (not slinky) buried at 4-5ft deep and pipes min 4-5ft apart.
House is about 250sqm over 2 floors and has 150mm solid insulation in the ground floor with 80mm concrete screed over the pipes. Walls have 200mm cavity with pumped insulation and 150mm solid concrete blockwork interior wall, also 50mm insulation between all walls and floors, standard apex roof with 400mm earthwool insulation. Triple glazed passive windows. All junctions and joints taped with air tightness tape before plastering (a seriously under rated procedure in this part of world) . Backed up with MVHR system.
Heat pump is also installed within the heat envelope of the house

Thank you for the detailed description, you have good insulation there. What is the energy rating of your house, can’t be far off passive

is it v warm in summer however

 

[neilo]

It's a 12kw ecoforest heat pump and is fed by 650m of ground source piping (not slinky) buried at 4-5ft deep and pipes min 4-5ft apart.
House is about 250sqm over 2 floors and has 150mm solid insulation in the ground floor with 80mm concrete screed over the pipes. Walls have 200mm cavity with pumped insulation and 150mm solid concrete blockwork interior wall, also 50mm insulation between all walls and floors, standard apex roof with 400mm earthwool insulation. Triple glazed passive windows. All junctions and joints taped with air tightness tape before plastering (a seriously under rated procedure in this part of world) . Backed up with MVHR system.
Heat pump is also installed within the heat envelope of the house

Do you open the windows to let some fresh air in?

 

[24/7 farming]

Thank you for the detailed description, you have good insulation there. What is the energy rating of your house, can’t be far off passive

is it v warm in summer however

Still not got around to getting the house rated!, defo not passive though as we wanted an open fire in the sitting room!, also wanted bifold doors onto the patio and they are not rated passive. Done our best, but it never ends... you could go right down to sealing the conduits in the walls to prevent drafts from the sockets if you wanted too!!

Do you open the windows to let some fresh air in?

The MVHR (Mechanical Ventilation & Heat Recovery) helps with controlling the temps and keeping the house from getting 'stuffy', basically a vent in every room, sucks air (at a very low constant rate) from the 'warm' rooms... kitchen, bathrooms, utility etc, and blows the fresh air into the rest of the rooms, creates its own circulation that way... (all internal doors have a 10mm gap to the floor to allow for circulation) it changes the air in the house every few hours (it heats the new air coming in using the 'stale' air being pumped out). Now when it hit near 30 during the summer there is not much it can do (although it runs 24/7 so does bring in cooler air at night time to cool the house). Glass areas are biggest culprit for heating the interior tho, but blinds are good at killing that. For the summertime though the fly screens are on the doors so they are usually open morning till night anyway if weather is good

 

[toquark]

Forget heat pumps in a domestic environment, I've got plenty of experience with them and they're nothing but hassle. Expensive hassle at that.

I am considering however the option of PV on the roof to power modern convection heaters in the house. They're probably too expensive to run off mains leccy, but if the price is right on pv units, it could work out better and so much simpler than pumps.

 

[Oliveau]

Iirc soil temp is relatively constant at around 10 degrees if you go 2m down? The GSHP works by extracting that heat, the same as a fridge or a/c unit in reverse.

Your log burner will have a considerably lower capital cost, with lower running costs and, arguably, a lower carbon footprint.

We have a big log burner in the sitting room which basically never goes out in the winter uses about 12 cu m of logs per year. A gas fired AGA in the kitchen - Yes it goes through about 3 tonnes LPG per year, but in normal years it’s off in July & August, and it heats DHW. In the summer when using the immersion heater the meter spins like crazy even though it’s using off peak power. There is also condensing gas boiler running radiators, but unless we have a freeze it only runs warm water as an anti-frost programme when the outside temperature is 3c or below. Basically the wood burner and the AGA do the job, and generally we leave all the internal doors open to circulate the heat downstairs & upstairs.
Everything is double glazed, but the French don’t seem to understand the principle of cavity walls - our house is rendered hollow concrete block and the webs in the blocks link the inner and outer skins. The idea in France seems to be to pour the heat in to warm the whole structure.

January & February in the warmth of South Africa’s Western Cape helps as well!