Beginning of the end for MCS?

[ProDave]

3 minutes ago, SteamyTea said:

That needs a lot of unpicking.

In what way?

 

Even if the houses were very well insulated, the cost of heating with an electric boiler is going to be 3 times as much as heating with an ASHP.

[Beelbeebub]

3 minutes ago, Stones said:

 

Although I imagine the challenge given the postage stamp sized gardens is where would the ground pipes go.  As you rightly point out a borehole would solve this, but how many GSHPS can a borehole support - presumably as you also say, local geology dependant

kensa are doing a project in the south west where they have put community bore holes under the road with brine pipe leading back to the homes.

 

They have worked out that the brine system can be communal even when each property has it's own HP.

 

It may be useful but the problem is i don't think there is enough ground heat for dense areas.  Most of the heat in the ground comes from above, except in geothermally active areas.

[SteamyTea]

35 minutes ago, Stones said:

but how many GSHPS can a borehole support

Is it 100W/m or there abouts.

Forget communal heating, the English are just too self centred to share anything. Recipe for disaster. So would have to be stand along for each property. 

 

[SteamyTea]

35 minutes ago, Beelbeebub said:

Because they would cycle right back into the heatpump?

Yes they would, we would have perpetual motion machines otherwise.

[SteamyTea]

36 minutes ago, ProDave said:

40 minutes ago, SteamyTea said:

That needs a lot of unpicking.

In what way

Individual usage patterns, different expectations, all sorts of things.

Just different energy tariffs could make a difference.

Yesterday's You and Yours showed, yet again, how hopeless the public understanding is. Not that many will listen to it.

As an example, two callers, both barn conversions. One pleased, other not. But no detail, so no way to make a decision. Totally pointless show in the end.

[saveasteading]

1 hour ago, SteamyTea said:

sinking boreholes is a pretty small cost.

No. Very expensive unless on a flowing aquifer or hot rock.

[saveasteading]

1 hour ago, ProDave said:

all the heating is with electric boilers

Have i heard right, that your power is all or mostly wind derived at 1/3 the cost but you are charged at the top rate as if gas or coal? The 2/3 is kept by your supplier?

[SteamyTea]

12 minutes ago, saveasteading said:

No. Very expensive unless on a flowing aquifer or hot rock.

What has a flowing aquifer or hot rocks got to do with drilling costs.

 

If someone asked me to drill 1000, 50 m boreholes on a new build site, I am sure I could do it cheaper than 500, 100 m boreholes scattered around the area.

We are just not used to drilling boreholes in the UK, so has become a self fulfilling prophesy.

[MikeSharp01]

1 hour ago, ProDave said:

Even if the houses were very well insulated, the cost of heating with an electric boiler is going to be 3 times as much as heating with an ASHP.

Have a word with / read of @TerryE's numbers on the Willis heater on straight economics it wins for a long time, eventually the ASHP will catch up but by then you would probably be close to needing a new heat pump as thy don't last forever do they!

[Carrerahill]

17 hours ago, sharpener said:

Now that Octopus have decided not to require MCS accreditation if you want to sell them your surplus PV 

 

 

do we think the same will happen to the requirement for MCS and heat pumps? Of course they are not involved directly in BUS except as an installer but I suspect they may have quite a lot of clout.

 

I found plenty of supplies didn't actually insist on MCS. When it came to PV I always thought MCS was a complete money making scam. 

 

I installed my own PV system, therefore not MCS accredited, if I do say so myself, my install is better than the other 2 around me. Why? Time, patience and care. 

[Beelbeebub]

3 minutes ago, MikeSharp01 said:

Have a word with / read of @TerryE's numbers on the Willis heater on straight economics it wins for a long time, eventually the ASHP will catch up but by then you would probably be close to needing a new heat pump as thy don't last forever do they!

Though the equation is different if you look at carbon. 

 

Even if the electricity is 100% renewable the generation capacity is considerably higher, which had a capital cost, albeit one not a visible to the consumer. 

[JohnMo]

2 hours ago, MikeSharp01 said:

Have a word with / read of @TerryE's numbers on the Willis heater on straight economics it wins for a long time, eventually the ASHP will catch up but by then you would probably be close to needing a new heat pump as thy don't last forever do they!

To run a Willis cost effectively you need a floor that can store the heat and slowly release over the day AND be on a low rate tariff AND a reasonably low total heat requirement. 

[JohnMo]

3 hours ago, SteamyTea said:

Is it 100W/m or there abouts.

Forget communal heating, the English are just too self centred to share anything. Recipe for disaster. So would have to be stand along for each property. 

 

Would have agree.

[saveasteading]

3 hours ago, SteamyTea said:

What has a flowing aquifer or hot rocks got to do with drilling costs.

 A hole into heavy clay is typically 80m deep to get enough surface area to extract heat from. Even then it runs out of heat.  Into sand with a flow of water to replenish the heat, they will be shallower.

Into hot rock they will be harder to drill but there is plenty of heat.

So the conditions affect the depth of drilling, and the number of bores required.

 

 

[Beelbeebub]

3 hours ago, SteamyTea said:

Is it 100W/m or there abouts.

Forget communal heating, the English are just too self centred to share anything. Recipe for disaster. So would have to be stand along for each property. 

 

https://www.homebuilding.co.uk/news/community-heating-with-boreholes-under-road

 

 

The only issue I can see is if someone over extracts from the community borehole array and causes the temp to drop for everyone. 

 

You could guard against that by having limits on what power HP you can fit, to some extent having limited pipe sizes into the property would do that. 

 

Of course the hypothetical heat pirate would also have to be using a lot of heat, so unless they are willing to just burn the heat to piss their neighbours off or are a cannibis farm, I don't think it would be an issue. 

 

A further guard would be to meter the heat and have it either as "unlimited subject to fair use" or outright charge per kwh.

[Beelbeebub]

It is quite a neat idea, there is a lot of high density housing with a public road outside. The road itself acts as a heat collector in the summer. 

 

The bore hole drilling would be about the same level of disruption as installing any other road services ie moderately but not catastrophically annoying. 

 

If the houses also cooled in the summer, they would pump heat in to replenish. In fact excess power from the grid, PV or even local industrial process could be used to recharge the ground in the summer. 

 

[SteamyTea]

23 minutes ago, saveasteading said:

A hole into heavy clay is typically 80m deep to get enough surface area to extract heat from

Ah right.

GSHPs are geology dependant.

Soils have about the same SHC as rock, around 0.8 kJ/kg.K.

Density is a little lower, say 2000 kg/m³.

If a 100 m borehole system can get a third of that energy out, down here, were the mean air temperature is 12⁰C (borehole temp is mean annual air temp) and assume the ground can be cooled to -15⁰C.

100 (m) X 2000 (kg/m³) X 0.8 (kJ/kg.K) X 27 (∆T) = 4,320 MJ.

Divide by 3

1,440 MJ, or 400 kWh.

That is obviously before any thermal replacement i.e. heat seep.

Would easily do my house, and a more modern place would probably use half the energy.

So I think it is a valid idea.

[Beelbeebub]

28 minutes ago, SteamyTea said:

and assume the ground can be cooled to -15⁰C.

Is that good assumption?

 

I may be wrong, but I thiught freezing the ground was a bad thing. Certainly close to the surface you'll get all manner of frost heave issues. Any vegetation eg lawns will suffer too. 

 

More importantly if the ground is pushed down to near or sub zero temps that means the return water from the borehole (to the HP)will be very low temp, which messes with the COP. 

 

GSHPs get good Scops because they never really see very cold source temps. It may be - 5C air temp, but all your HP sees is a balmy 12C from the ground. If it starts seeing - 5C it will perfrom poorly. 

 

 

 

[SteamyTea]

25 minutes ago, Beelbeebub said:

that good assumption

One has to start somewhere.

26 minutes ago, Beelbeebub said:

Certainly close to the surface you'll get all manner of frost heave issues

Not so much with a borehole.

27 minutes ago, Beelbeebub said:

More importantly if the ground is pushed down to near or sub zero temps that means the return water from the borehole (to the HP)will be very low temp, which messes with the COP

As earlier, have to start somewhere.

Borehole systems work very well, quite a lot of places down here have them, may be b cause Kensa are local.

[MikeSharp01]

42 minutes ago, JohnMo said:

To run a Willis cost effectively you need a floor that can store the heat and slowly release over the day AND be on a low rate tariff AND a reasonably low total heat requirement. 

Exactly. That is what we have (I think) but I will do the calcs myself again when the time comes and will look at the full equation - carbon in / carbon out and then on a 10 year horizon make the call.

 

 

 

[Beelbeebub]

50 minutes ago, SteamyTea said:

One has to start somewhere.

Not so much with a borehole.

As earlier, have to start somewhere.

Borehole systems work very well, quite a lot of places down here have them, may be b cause Kensa are local.

They do seem to work well. I'm not questioning that. 

 

I was just questioning the assumptions in your napkin calculation. 

 

You h are right, you do need to start somewhere, but I would suggest setting the lower limit of the source at 0C (or maybe a bit above) rather than - 15C as that is unrealistic. 

 

A quick Google shows freezing of GSHP boreholes is generally to be avoided. Several installer FAQ's address this directly by saying (in effect) "a week designed system won't freeze". They don't say "freezing isn't a biggie" 

 

I found this from a study in Sweden. 

 

"... This paper concerns a rare freezing problem that occurs in 1 of 10,000 systems. In such cases freezing that occurs in the boreholes as a result of heat extraction creates an over pressure that flattens the pipe system, thereby stopping the circulating of the heat carrier fluid. Even if this is a rare problem it means big problems for the unlucky individuals and also for the industry since one such problem reduces the market in that region." 

 

I think that implies that wholesale freezing of the borehole is considered a bad thing that is rarely encountered because designers work to avoid it. 

[SteamyTea]

3 minutes ago, Beelbeebub said:

I was just questioning the assumptions in your napkin calculation. 

It was really to point out that there is quite a lot of energy stored in soil.

 

What sort of temperatures is the brine that gets pumped around GSHPs?

 

I was thinking about your radiator idea.

I may go looking for an old fridge, put a bucket inside it, plumb out of there to a pump and pass it though some radiators.

By boxing in the fridge, with an airgap, a fan can blow air though it, kind of Water to Air HP.

[JamesPa]

Returning to the original question, I doubt it.  PV grants ran out in approx 2019 after being in existence for 10+ years.  HP grants have a way to go.

 

Having said that, all it really needs for heat pumps is some tweaks on the PD rules and a steady increase in the disincentives to fit/replace boilers so that by say 2030 it's a no brainer.

 

With a determined government, not that difficult really.

 

Let's hope we get a determined government at the next election.

[Beelbeebub]

2 minutes ago, SteamyTea said:

It was really to point out that there is quite a lot of energy stored in soil.

Agreed. Borehole GSHPs might be a useful tech if the cost of borehole drilling can be lowered. They do have smaller units, and potentially higher efficency. 

 

The communal borehole network idea is interesting as it can get around the high individual cost by slitting over many users, and reduce the risks of a dud hole, especially if you join an existing proven network in your street. 

 

 

[Huckleberrys]

4 minutes ago, JamesPa said:

Returning to the original question, I doubt it.  PV grants ran out in approx 2019 after being in existence for 10+ years.  HP grants have a way to go.

 

Having said that, all it really needs for heat pumps is some tweaks on the PD rules and a steady increase in the disincentives to fit/replace boilers so that by say 2030 it's a no brainer.

 

With a determined government, not that difficult really.

 

Let's hope we get a determined government at the next election.

The trouble with this though is that heat pumps will not be right for every house though, especially retrofitting on older properties. I have advised as many customers against them as I have fitted new ones in other properties that are suitable