Clean Heat Market Mechanism to incentivise heat pumps

[RobLe]

9 minutes ago, Beelbeebub said:

If someone could come up with a non toxic, non flammable, low GWP, low odp refridgerant - then I would say have at it.  We should be selling those units on Amazon and in Screwfix.

CO2 fits all of those criteria.  Sadly it needs ludicrously high pressures (like 150bar instead of the usual 15bar maximums), so I’m not convinced it will go mainstream.  If you could fit a propane system together without brazing, it would be safe enough for diy I think.  We’ve been looking for magic new refrigerants for 100 years, and we’re back to one of the earliest ones - propane - again, so I wouldn’t hold your breath waiting for a significantly better one.

[Iceverge]

1 hour ago, Beelbeebub said:

If someone could come up with a non toxic, non flammable, low GWP, low odp refridgerant - then I would say have at it.  We should be selling those units on Amazon and in Screwfix.

 

 

These currently have a COP of about 2.5. 

 

Ideally if you could double it it might be a solution. 

 

 

[Beelbeebub]

11 hours ago, RobLe said:

CO2 fits all of those criteria.  Sadly it needs ludicrously high pressures (like 150bar instead of the usual 15bar maximums), so I’m not convinced it will go mainstream.  If you could fit a propane system together without brazing, it would be safe enough for diy I think.  We’ve been looking for magic new refrigerants for 100 years, and we’re back to one of the earliest ones - propane - again, so I wouldn’t hold your breath waiting for a significantly better one.

Co2 fits except for efficiency (at heating temps)

 

It's less efficient than other solutions. Where it does shine is relative efficiency at very high temps (80C etc).

 

If you want to heat water to near boiling then co2 is your best bet.

 

If you want to heat a room to  20C, less so.

 

Plus your point about pressures.  I think you might need steel pipes for those pressures, plus the consequences of a burst are pretty bad.

 

As for a non braze solution, yes. Something akin to push fit plumbing.  Maybe with pre charged lines. I believe Daikin have a solution.

 

Or maybe ship with everything prefilled with lightly pressurised dry nitrogen.  That is then vented to Atmos and the prepacked refridgerant charge entered.  You'd have to live with some dry nitrogen in the system.

[SteamyTea]

One way to increase the efficiency of an ASHP is to increase the size of the external heat exchanger (the radiator).

Our planning system puts a limit of 0.6 m³ for a permitted development unit I think though.

[Beelbeebub]

11 hours ago, Iceverge said:

 

 

These currently have a COP of about 2.5. 

 

Ideally if you could double it it might be a solution. 

 

 

Looking at the Powrmatic version, specifically as a replacement for storage heaters.

 

I think getting the cop up is going to be hard as it's a function of the mass of air you can flow through the Heatpump. The less mass, the greater the temp drop (for a given power) and thus the colder the downside of the HP needs to be.

 

Defrost might be an issue.

 

I did think that something like that acting as a heatpump powered heat recovery ventilation unit might be good for damp properties. Would provide really good ventilation with a decent amount of heat.

[SteamyTea]

7 minutes ago, Beelbeebub said:

I did think that something like that acting as a heatpump powered heat recovery ventilation unit might be good for damp properties. Would provide really good ventilation with a decent amount of heat.

You can get them, our old mate @Jeremy Harris had one.  Can't remember the make.  Think it was only 2 kW_p, which would me useful in my house, but for larger properties several may be needed.

[Iceverge]

2 hours ago, Beelbeebub said:

I think getting the cop up is going to be hard as it's a function of the mass of air you can flow through the Heatpump. The less mass, the greater the temp drop (for a given power) and thus the colder the downside of the HP needs to be.

 

Agreed, as the bulk of the air needs processed is external air then maybe having the unit outside and ducting hot air inside is the answer. Effectively a "monoblock" A2A. 

 

2 hours ago, Beelbeebub said:

Defrost might be an issue.

 

Anymore so than another heat pump?

 

2 hours ago, SteamyTea said:

Think it was only 2 kW_p, which would me useful in my house, but for larger properties several may be needed.

 

A Genvex unit from memory.  

 

 

[SteamyTea]

8 minutes ago, Iceverge said:

 

Agreed, as the bulk of the air needs processed is external air then maybe having the unit outside and ducting hot air inside is the answer. Effectively a "monoblock" A2A. 

 

 

Anymore so than another heat pump?

 

 

A Genvex unit from memory.  

 

 

Yes, you are right.

Anyone else got one as it would be interesting to know how good, or bad, they are.

[Beelbeebub]

4 hours ago, Iceverge said:

Anymore so than another heat pump

I was thinking handling the melt water inside and having to drain it out through the wall might be problematic. At least moreso than simply letting it drop out of the bottom of the unit into a soak away.

[Iceverge]

2 hours ago, Beelbeebub said:

I was thinking handling the melt water inside and having to drain it out through the wall might be problematic

 

A2A units do this with a drain to outside. 25mm pipe or so. 

 

 

Trouble with a split A2A is that there's a few tools and a level of competence required that an average jobber might not have.  

Any donkey (myself included) would be fairly confident of knocking a couple of holes in a wall, patching it up and bolting an external unit in place.  

[Beelbeebub]

1 hour ago, Iceverge said:

 

A2A units do this with a drain to outside. 25mm pipe or so. 

 

 

Trouble with a split A2A is that there's a few tools and a level of competence required that an average jobber might not have.  

Any donkey (myself included) would be fairly confident of knocking a couple of holes in a wall, patching it up and bolting an external unit in place.  

Yeah, but the condensate from cooling is a slow steady trickle.  The condensate from defrost is a sudden high flow as all the condensate from the last 30mins or so is released at once. It's not an impossible problem, but I can see it being very tricky to handle, plus the a2a monoblock wouldn't have much stored heat volume.  A a2w unit already needs a fair volume of water to store heat for defrost and this unit would have none.  The defrost might have to be a straight up electric trace heater on the coil, which would impact COP.

 

But you're right, the plumbing of a2a split units is a bit beyond the average DIYer simply because of the tools involved aren't worth getting for a one off job.

 

That is the potential advantage of a2w based systems, they can be tackled with fairly rudimentary skills and the complex refrigeration side of things is compleatly "black box" sealed. The problem is the system design of water systems is more complex and even professionals cock up.

 

Maybe if we used fan coils more.  They would remove alot of the issues associated with too small emitters and are pretty simple devices themselves.   If you could buy a 3kw fancoil for about the same price as a 3kw radiator that would be a big step forward.

[Iceverge]

56 minutes ago, Beelbeebub said:

.  The condensate from defrost is a sudden high flow as all the condensate from the last 30mins or so is released at once. It's not an impossible problem, but I can see it being very tricky to handle, plus the a2a monoblock wouldn't have much stored heat volume

 

How do existing split A2A units cope with this? 

 

Going back to the all in one unit. The main benefit is it's simplicity and as soon as you get to a monoblock coupled to a fan coil you're not much better off than an A2A mini split. 

 

Doing some sums........ a 2kw A2A split uses about 10m3/min or 0.166m3/sec so no small change. Assuming we want to keep air flow at a reasonable speed for noise say....  5m/s then we would need 2 x holes (inlet/outlet) of diameter 200mm ish. 

 

Not impossible. 

 

 

 

That all ties in with this unit which requires 2 x180mm holes for 3.6kw but at a COP of only 3.6 

 

electriQ iQool 12000 BTU Wall Mounted Smart Air Conditioner with Heat Pump - No Outdoor Unit Needed IQOOL-SMART15HP | Appliances Direct

 

 

Does anyone on here have one? 

 

 

 

 

 

[Iceverge]

3 minutes ago, Iceverge said:

 

How do existing split A2A units cope with this? 

 

Going back to the all in one unit. The main benefit is it's simplicity and as soon as you get to a monoblock coupled to a fan coil you're not much better off than an A2A mini split. 

 

Doing some sums........ a 2kw A2A split uses about 10m3/min or 0.166m3/sec so no small change. Assuming we want to keep air flow at a reasonable speed for noise say....  5m/s then we would need 2 x holes (inlet/outlet) of diameter 200mm ish. 

 

Not impossible. 

 

 

 

That all ties in with this unit which requires 2 x180mm holes for 3.6kw but at a COP of only 3.6 

 

electriQ iQool 12000 BTU Wall Mounted Smart Air Conditioner with Heat Pump - No Outdoor Unit Needed IQOOL-SMART15HP | Appliances Direct

 

 

Does anyone on here have one? 

 

 

 

 

 

 

Actually scratch that. It's the internal unit of a standard split unit that is about 10m3/min not the external unit which I will be far greater than that. 

 

Hence all the noise complaints for the above unit with it's 180mm holes. 

 

 

[Beelbeebub]

11 hours ago, Iceverge said:

How do existing split A2A units cope with this?

I think by outside. They just defrost and the water falls out the bottom. If the outlet blocks it just overflows outside which is less of an issue than inside!

[Beelbeebub]

The capacity and efficiency of any HP is constrained by the airflow and the airflow is constrained by the noise.

 

External HPs can flow alot of air at a low velocity (for low noise).

 

The internal HPs are limited by the ducts. 

 

Drilling ever larger holes inthe wall becomes a problem.  Even the 180mm ducts are a bit too big really. 150mm or even 125mm would be easier, but then the power or efficiency would be lower or the noise higher.

 

Maybe if you could have a low powered, high efficiency device that was easy to install (say single 150mm concentric duct but only 1kw) and it was really cheap (say £250) you might have a situation where you just installed 2 or 3 in a room.

 

Imagine this but with a small HP (and better looking)

 

[Iceverge]

I suppose ultimately it boils down to:

 

1. Drilling huge holes in the wall 

2. Drillings lots of slightly smaller holes in the wall.

3. Accepting the install complexity of an A2A mini split. 

 

 

My impression is the world has already decided. 

 

 

[Beelbeebub]

1 hour ago, Iceverge said:

I suppose ultimately it boils down to:

 

1. Drilling huge holes in the wall 

2. Drillings lots of slightly smaller holes in the wall.

3. Accepting the install complexity of an A2A mini split. 

 

 

My impression is the world has already decided. 

 

 

I think it's inevitable we are going to end up with boxes outside our homes

 

One interesting concept I've seen for high-rise properties is a central brine (glycol) water network drawing heat either from ground source or from big air exchangers in central location. This brine is piped to each flat where a small water to water unit does the actual heat pumping using the communal external heat exchanger.

 

Sort of a hybrid between a whole building heating system with heat meters and the individual units with multiple external boxes 

[JamesPa]

3 hours ago, Iceverge said:

I suppose ultimately it boils 

 

 

I think an architect could slightly modify this and declare it beautiful.  Repeated patterns are a common theme in architecture and the natural world.  It just needs a bit more symmetry and consistency.  

[SimonD]

I received an email from one of my suppliers today announcing the start of the CHMM on 1st January 2024 and the industry response. Most major boiler manufacturers have confirmed they are simply going to add between about £100 - £140 as a levy on boiler sales. So much for incentivising a market shift. Instead it's ended up as a low level inconvenience tax which will hit those least able to afford it. At the same time gas boilers and heat pumps on new builds are exempt from the tax and certainly no ban in sight for fossil fuel boilers in new builds.

 

It's just a total farce.

 

 

Edited December 15, 2023 by SimonD

[SteamyTea]

1 hour ago, SimonD said:

Most major boiler manufacturers have confirmed they are simply going to add between about £100 - £140 as a levy on boiler sales

Is that because:

"Boiler manufacturers will be required to sell heat pumps equivalent to 4% of their boiler sales in 2024 and 6% in 2025, increasing to hit the overarching target by 2028. "

 

https://www.current-news.co.uk/paving-the-way-to-net-zero-kensa-groups-optimism-in-the-clean-heat-market-mechanism/

[SimonD]

3 minutes ago, SteamyTea said:

Is that because:

"Boiler manufacturers will be required to sell heat pumps equivalent to 4% of their boiler sales in 2024 and 6% in 2025, increasing to hit the overarching target by 2028. "

 

Yes, basically. If you're a heatpump manufacturer you're probably going to be rubbing your hands. The main problem is that it's a supply side scheme.....without the demand. It's not like people will now suddenly start queueing up for heatpumps now is it?

[Beelbeebub]

Realistically the only way to make people switch is to make it the cheaper option.

 

The upfront cost can be dealt with via install subsidies, though that does just encourage the install price to remain high.

 

The bigger issue is the cost of running the HP. This is a common point brought up by the anti brigade.

 

The government need to make HPs the cheaper option. Then people will be kicking the door down to install them.

 

One issue is the green taxes on electicty Vs gas.

 

About 15-20% of the elec bill is green taxes, less than 5% for gas.

 

If you shifted the taxes over in a moremormlessncowt neutral way, then the average bill of a dual user would stay the same, only the proportion spent on each fuel would change.

 

But the elec only user would see a fall in costs and the break even SCoP for HPs where they cost less than a gas boiler would fall making HPs more attractive.

 

 

[Beelbeebub]

Quick estimate, ignoring standing charges etc.

Assume

Gas 7pkwh

Elec 28pkwh

 

So break even SCoP is about 4. Fairly hard to achieve.

Annual Gas usage 12,000kwh 

Annual elec Usage 4,000kwh

 

Annual Gas cost £840

Annual elec cost £1,120

Total £1,960

Green tax on gas is 5% ie £168

Green tax on elec is 20% ie £224

 

If we swap the elec taxes to gas

Gas £1,064

Elec £896

 

Unit cost is now 9pkwh for gas and 22pkwh (rounded in favour of elec). 

 

Now the break even SCoP is now 2.4, much easier to achieve. Most properties could achieve that with a very mild upgrade to emitters.

 

 

 

[Iceverge]

 

2 hours ago, Beelbeebub said:

Realistically the only way to make people switch is to make it the cheaper option.

 

Its too simple a solution. Stupid people would never believe it could work. 

 

 

[Beelbeebub]

1 minute ago, Iceverge said:

 

 

Its too simple a solution. Stupid people would never believe it could work. 

 

 

I suspect it won't be "stupid people" who will resist.

 

Unfortunately climate change has become enmeshed in the wider "culture war".

 

There are people out there who will resist heatpumps noatter how much financial sense they make because they don't like Greta Thunberg or "the woke" or the EU or something.

 

At the end of the day I don't actually care. They can pay more to subsidie the sensible.