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Pretty soon, heat pumps will be able to store and distribute heat as needed

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Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#61

Post by Xylakant »

DrScientist wrote: post #34
ZeroGravitas wrote: post #30

Earlier quoted context omitted.

It also exists, as described in the headline, as a tank of heated water. The phase change stuff has positives like taking up less physical space but it's also a much less mature tech than storing hot water.

Indeed. In the UK there was a unfortunate trend of ripping out these energy storage devices and replacing hot water tanks with on demand electric hot water heating ( only heat the water you need ). And new builds often have no tanks ( as it saves space in the new tiny homes ). Very short sighted in my view - a very simple way to store energy and everyone uses hot water directly.

it also reduces peak load - you can heat water up slower with a lower powered heater. I have a 35 liter warm water tank in my garden shed that pulls about 3.5kw - an equivalent on demand heater would need 14kw or more.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#62

Post by jandrese »

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climates they make your house work that much harder to keep the space warm.

The most optimistic hope is that the government mandate will force enough demand that manufacturers can enjoy some economies of scale and actually try to compete on price. I don't think this will happen anytime soon.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#63

Post by a_better_world »

DrScientist wrote: post #34
ZeroGravitas wrote: post #30

Earlier quoted context omitted.

It also exists, as described in the headline, as a tank of heated water. The phase change stuff has positives like taking up less physical space but it's also a much less mature tech than storing hot water.

Indeed. In the UK there was a unfortunate trend of ripping out these energy storage devices and replacing hot water tanks with on demand electric hot water heating ( only heat the water you need ). And new builds often have no tanks ( as it saves space in the new tiny homes ). Very short sighted in my view - a very simple way to store energy and everyone uses hot water directly.

My hot water tank once fell off the wall. On Christmas day. Expensive repair.

Hot water tank was in the basement, which was not insulated. So the mass of hot water contributed very little as a heat reserve for the house.

House was in a northern clime.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#65

Post by Xylakant »

mrguyorama wrote: post #60
coffeebeqn wrote: post #33

Earlier quoted context omitted.

There’s also solar thermal panels that heat up a liquid circulating in the system and cut out the need for a battery - and can just store the heated liquid.

Efficiencies and effects are at the point where taking a photon, converting it into an electron, and using that electron to pump heat is more efficient than turning that photon perfectly into kinetic energy. Similarly, in mild weather, it is more efficient to burn hydrocarbons and turn it into electricity to run a heat pump than use that hydrocarbon for it's heat energy directly. Pumping heat is more efficient than m…

Thermal solar panels have the advantage of being very simple and surprisingly effective. But if you're lacking space to put up both solar cells and thermal, you can use combined panels which have a solar cell with a backing thermal system. The interesting thing is that these combined panels outperform solar cells even when it comes to electricity generated because solar panels loose efficiency as they heat up, so cooling them actually improves efficieny. Combined panels are much more expensive, though.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#66

Post by Tor3 »

jandrese wrote: post #62

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climate…

I had a heat pump installed in 2010. In a cold climate. Only used for heating. It paid for itself extremely quickly - less than three years. It's still going strong, in 2026. It's important to maintain it regularly, i.e. deep cleaning every two years or so. The first time I got a company to do it for me, and the technician taught me how to do it all by myself, so that's what I do. In any case having a professional doing it wasn't expensive either. And I clean the dust filters (very easy) every second week or so.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#67

Post by matwood »

jandrese wrote: post #62

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climate…

I think a heat pump only for water isn't the right way to go. In the EU, new systems I see use a single heat pump for all heating and cooling in the house including heating water.

I do miss my natural gas on-demand water heater from when I lived in the states though. Unlimited hot water was nice, and it took up almost zero space.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#68

Post by Xylakant »

rekabis wrote: post #2

I would love to see a bus-sized version for year-long temperature moderation. Like, drop house heat into it during the summer so it can re-heat the house over the winter, and pull all the heat out of it by Spring so that it can cool the house over the summer. Bus sized because that amount of thermal mass is bound to take up a lot of space, but capable of being buried so that it doesn’t actually take up property space…

This exists, in german it's called Eisspeicherheizung. You have a few cubic meters of water buried in a concrete bunker and you use a heat pump to pull energy out of the water until it freezes. The system not only uses the thermal mass of the water, but the thawing/freezing energy which is higher than the energy required to heat water by 1degree by a factor of 80 - meaning if you freeze 1kg of water, you need to pull out enough energy to heat one kg of water by 80 degrees.

You can then use a heat pump that's optimized for the expected temperature range and you don't even need to insulate your water storage tank - you actually want the cold in winter to seep out into the surrounding soil, free energy.

In summer you have cold storage for your AC.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#69

Post by spockz »

matwood wrote: post #67
jandrese wrote: post #62

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climate…

I think a heat pump only for water isn't the right way to go. In the EU, new systems I see use a single heat pump for all heating and cooling in the house including heating water. I do miss my natural gas on-demand water heater from when I lived in the states though. Unlimited hot water was nice, and it took up almost zero space.

Which models are you looking at? I was still quoted separate pumps for floor heating and a boiler with the pump built in taking the energy from the air two years ago.

Is it something from nefit by any chance?

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#70

Post by thunfischbrot »

matwood wrote: post #67
jandrese wrote: post #62

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climate…

I think a heat pump only for water isn't the right way to go. In the EU, new systems I see use a single heat pump for all heating and cooling in the house including heating water. I do miss my natural gas on-demand water heater from when I lived in the states though. Unlimited hot water was nice, and it took up almost zero space.

Afaik heat-pumps in the EU can provide unlimited hot water–what am I missing?
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