Heat Pumps

I stayed in a 15th century pile that was heated by coal stoves. It would have been logs originally, but at some point in the 19th century it was 'upgraded' to coal (not exactly native to Suffolk) and the patent stoves were installed. Then it got listed and so the coal stays. That's the sort of place that would be difficult to heat with an ASHP.

If you live in a non-listed house with central heating then you can make it warm with a big enough high temperature heat pump, but it's then a question of the market pricing of gas and electricity compared with the SCOP of your model as to whether it makes economic sense.

ASHPs are also going to be difficult in non-ground-floor flats where you can't mount an outdoor box, unless there's a whole building solution.

Theo

It’s a shame that there aren’t more combined heat-pump and tank combos that would be installed outside. So many houses that were designed around combis (or modified to use the space where a tank would have gone) just don’t have room internally for the tank/tanks.

Tim

For grant purposes the tank has to be sized on the number of bedrooms, not the number of occupants I believe.

Tim

These things do not all function like 10K BTU window air conditioners.

Those happen to suck, in the human condition ("can't sleep in motel").

By varying the engineering parameters, you can make them quieter.

When I changed out some external equipment fifteen years ago, one of the first things that happened is the neighbour leaned over the fence and said how much quieter the thing was :-)

That's progress for you.

Paul

Americans have those and call them 'heat pump water heaters', with the heat pump integrated at the top of the cylinder. They often put them in the garage, which may benefit from the cooling/dehumidification depending on the climate zone.

Trouble is the heat pump is tiny - 750W electrical load = 2.2kW heating. That means they have to run them all day to heat any decent volume of water.

The problem with putting your cylinder outside in our climate is the risk of freezing. On a regular ASHP system all the outdoor loop is either glycol mix (ie antifreeze) or there are freeze valves to dump it if the liquid gets below 5C (normally you'd expect the ASHP to kick in to prevent that, but suppose the house is empty and somebody had pulled the main breaker). If you start putting bathing water outside it obviously can't have glycol in it, and you can't dump out all of it in case of freezing.

Theo

What happened here, when we built multiple nukes on large sites, is yes, the original price quoted for the lekky, was dirt cheap. It's because they had no idea at the time, what operation and maintenance cost would be for the things. They did not really know, how often on average a unit would need to be re-built in the core.

For that class of reactor today, the costs are known with a bit more precision.

And bad things happen, if you only build one of the things on a site. One area of the country tried to go cheap, by building a single unit, and the cost of replacement lekky while a rebuild of the core was going on, just about sank them. They have to go offline at some point, and you need a pool of them to smooth out the bumps.

The SMRs we are getting, the type/class will be different in the sense the unit is smaller, and the scale of doing various things might make a slight difference. Since the operating principle and the refueling method are knowns ("have seen it before"), the maintenance estimates for the thing should be a LOT more realistic than the pie-in-the-sky numbers of the first generation. They promoted the idea of using *resistive heating* with the first generation, and a couple of people tried it. But they later removed the units, because as hard as it is to believe, making a big resistive heater reliable, was harder to do than it looked. One of my buddies at work came in one morning "one element just blew on the electric furnace, down to 75% capacity", and that was one of the events that led to the unit being thrown into the nearest field.

At least with heat pumps, the electricity usage is a bit more intelligent. Still not perfect, but better.

From a resiliency perspective, we should continue to work on the infrastructure for more than one heating method, as you never know when one of the methods could go flat bust. (No wind blows, or no LNG tanker shows up.) It helps to have an alternative to use. You don't want to be a slave to a single-source solution. Maybe you already have half-a-cord of wood sitting in the back yard :-)

Paul

That seems to assume the installed equipment would outlive you. Not a safe assumption with so much 'modern' heating kit. That 'someone else' would have to pay for a new lot of equipment to be installed.

Same would be the case for me but for the 2 or 3kWh needed to heat water I'd just use the immersion.

No, that was fusion.

The problem is that the cost of *everything* is vastly higher than the FUEL cost. In electricity generation.

'Free' wind needs billions spent on making it work reliably.

Nuclear power will be cheap. Gas was cheap and gas prices went down with N Sea gas.,

Things *do* get cheaper. In 1885 I paid £800 for a PC clone. This machine is way more powerful and overall cost me about £400

In 1995 an 'always on' 64k internet connection cost around £5000 a year

My FTTP always on connection is 10Mbps up 40 Mbps down and costs me about £360 per year

Rolls Royce is aiming for a nuclear SMR station cost of around around £3.8 million per MWe.

Hinkley point is currently looking like £10 million per MWe.

RR is estimating 4-6p a unit cost over its lifetime, comparable with gas prices now.

Hinkley point have contracted for 9p

Wind and solar typically cost 15p-45p plus the cost of redundant grid, battery and backup.

Now obviously the electricity companies will try and turn the difference into profit, but there is only so far OFGEN will let them go...

Are you sure about that? Installations I've seen simply have a tank for DHW. There is no call to store hot water for space heating

On 31/05/2025 18:43, Spike wrote: the cost of *everything* is vastly higher than the manufacturing cost.

Gas prices are not high. That is a greenwashing lie.

Gas works out at around 5p a unit and with a reasonably efficeint boiler nearly all of that will heat the house

Even a 4:1 uplift heat pump barely matches that at 20p electricity prices.

And when you need the most heat in a cold winters night you wont get that 4:1 uplift anyway.

Gas *power station* prices are high not because the gas is expensive, but because it costs a lot of money to keep a gas power station spinning and not earning any money ready to cover a 3 hour peak demand every day.

And it doesn't make sense to build an expensive 65% efficient CCGT just for a few hours a week when you van bang in a 40% efficient OCGT.

Well I think we all know that, except the people who have them who cant admit what a useless pig in a poke they were sold

Dead wrong. Nucler power was proftaible at an ex-site cost of 4-5p a unit and competitive with coal for baseload.

So troo was gas when we were pumping it out of te Notrth Sea.

the whole cost of a reactor is in the Capex and the inters on teh denbt Fuel and maintenance and even decommissioning are peanuts by comparison

They were always known

That makes no sense.

What happened to the nuclear industry is two things. After Sizeweell B which was the fiorst time someone siad '#lets just buy in a priven dfesign' which was delieverd pretty much on time and on budget, two things happened

Interest rates climbed through the roof,and the cost of a reactor trebled because of that, and then North Sea gas came ashore at silly prices and it was a no brainer to switch to gas.

Since then the industry has been deliberately strangled by EU (Euratom) regulation to the point where a basically simpley construction project that could be built in a couple of years now takes 20.

Because German Greens and a coalition government decided that Germany wasn't going to have more nukes and was going to waste money on windmills instead.

Since the operating principle

Bullshit. O & M costs have never ever been an issue for nuclear,. Only capex.

France runs almost exclusively on resistive underfloor heating,. So does Sweden. So dies every immersion heater. You are spouting mire bollocks again

Noithing is perfect

Wood and oil.

You're living on another planet. Decommissioning costs are huge. However they can generally spread over 100 years but we're not stupid and they're not peanuts. Numbers range from £25b to £140b.

There was no crystal ball however hard you think there was.

You do understand that nuclear reactors have extended refuelling times?

The UK had a veto over any of these rules. It actually supported these changes.

And because they were cheap enough and payback quick enough for private money to provide the required investment.

However we don't know the true life-costs of these.

Again you are living on anther planet? Decommissioning generally costs more than any capex.

Yet 10 times as meany heat pumps are installed in France than the UK. You should get out more and stop reading Trump's fake news.

Heat pumps feature in 40% of Swedish households. Do you believe the crap you write?

You are spouting even more.

Fossil fuel for backup heat sounds a good plan.

Where do you get that figure?

Capital cost for small scale is about £1000/kW. Upper end generation would be

And again (as usual) you seem to assume that other costs, primarily environmental, of non-renewables are zero.

Indeed. Good luck with that.

The capital costs of a small scale solar installation rarely includes an upgrade to the electricity supply to the house to feed back into the grid. With a large scale installation the cost of the panel, plus fitting, may not be the most expensive part of the installation. However the extra cost just determines the payback period. The cheaper the selling price of the electricity the longer the break even point on the investment. But.. not all the costs have to be met by the large solar installer - the grid may pay the cost of the connection to the distribution system. In the end it's the consumer that pays the total bill.

The more we rely on solar the more we rely on the backup needed when the sun doesn't shine especially in winter when we all have converted to electric central heating and all are driving EVs. It's much the same with any other intermittent source that is part the system. The costs of the backup has to be factored into the equation.

If by “small scale” you mean your average home solar system, upgrades aren’t needed.

Tim

Is that in Canada? CANDU is supposed to allow online refueling.

When I bought this house in 1990 it had a cast iron lump, one thermocouple later it still has the same boiler. Replacing it with something modern isn't on my list. I think the way that SEDBUK ratings are calculated changed* some time ago, but before they did, it was only a single digit difference in efficiency from combis of the time.

I've changed radiators from singles to doubles as I've done-up each room, and it's had the pump replaced.

That's what tends to happen when younger couples buy houses after older people have died/moved into a home ...

I had no idea that Mr Babbage was making them so cheaply at that time.