[HN Gopher] Pretty soon, heat pumps will be able to store and di...
___________________________________________________________________
Pretty soon, heat pumps will be able to store and distribute heat
as needed
Author : PaulHoule
Score : 118 points
Date : 2026-02-01 18:15 UTC (1 days ago)
(HTM) web link (www.sintef.no)
(TXT) w3m dump (www.sintef.no)
| rekabis wrote:
| 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.
| syntaxing wrote:
| So...geothermal? I wish this was possible too but I don't see
| how it will work scientifically. Water is one of the chemicals
| that have one of the highest thermal mass/specific heat (maybe
| 1/3 of salt hydrates). Even then, you have to bury a crapton of
| water underground. This design mentioned in the article is more
| for short term, like 12 hours storage (since they're
| accommodating for solar in nighttime)
| Neywiny wrote:
| Is geothermal not the opposite of that? My understanding was
| that the geothermal MO is that there's virtually infinite
| thermal mass in the earth so it won't heat/cool, not that you
| heat/cool your local chunk
| syntaxing wrote:
| To a certain extent, yes. The reason why the water is there
| is because the thermal flux of the ground is low, so the
| large mass of water provides a strong buffer. But you can't
| cheap physics. You would need a crap ton of salt hydrate to
| accommodate a whole season of heat needs, even if you don't
| factor in thermal loss from the container.
| rekabis wrote:
| Geothermal needs either a horrifically expensive vertical
| bore hole going down a few hundred metres, or a good acre of
| land for laid-down piping. I have neither the money nor the
| horizontal space. So I am thinking something compact that
| needs to go only about 6-10m vertically into the ground (so I
| can hide it fully underground with about a metre of soil on
| top), and take up the horizontal space of 4 parked cars. I
| have more than enough room and cash to have that cube of
| space dug out.
|
| And being on an alluvial plain, if I filter out all the rocks
| larger than a pea, a good 90+% of what is dug out can
| immediately be trucked away.
| stubish wrote:
| You seem to be describing ground sourced heat pumps. If you
| wanted, you could insulate a a chunk of foundation or earth to
| avoid heat loss. But just the ground under your building seems
| to work well enough.
| rekabis wrote:
| Ground sourced heat pumps need either a horrifically
| expensive vertical bore hole going down a few hundred metres,
| or a good acre of land for laid-down piping. I have neither
| the money nor the horizontal space. So I am thinking
| something compact that needs to go only about 6-10m
| vertically into the ground (so I can hide it fully
| underground with about a metre of soil on top), and take up
| the horizontal space of 4 parked cars. I have more than
| enough room and cash to have that cube of space dug out.
|
| And being on an alluvial plain, if I filter out all the rocks
| larger than a pea, a good 90+% of what is dug out can
| immediately be trucked away.
| fy20 wrote:
| I ran the numbers for this a while ago. I live where we have
| proper winters (currently -22c). I wanted something simple just
| with solar thermal and water pumps (no heat pump). Sand
| batteries work at an industrial level, but for domestic use you
| want something simple so that means just water.
|
| A 100m3 (100,000 litres or 26,500 gallons) cylindrical water
| tank (approx 5x5m) buried and insulated with 50cm of XPS could
| provide around 4000kWh of deliverable heat throughout winter.
| Which would be more than enough for heating and domestic hot
| water for my house.
|
| In the summer you'd use solar thermal to charge it to 85c. In
| the winter you'd run water through underfloor heating and
| discharge it to 35c (so you just need a mixer valve and pump).
|
| The structural engineering part of it isn't actually that
| complicated (with a garden on top, not a house). You can buy
| plastic water tanks of that size, it just needs to be buried
| and have XPS foam placed around it.
|
| Because it's volume, it scales up well. An extra one meter in
| each direction would increase the volume by around 60%, but you
| have a lower overall heat loss, so the heat capacity would more
| than double.
|
| The important part of it is the XPS foam though, without this
| the loses are too great and you don't retain any heat. This is
| why insulating your foundation and slab is so effective.
| eande wrote:
| Interesting practical approach to actual build it. Did you do
| a cost analyses or RoI?
| bilbo-b-baggins wrote:
| So... store heat in an insulated swimming pool 10ft deep,
| 30ft wide, and 90ft long, at 185F, above the service temp for
| XPS foam, got it, ok. At least you could also use it to sous
| vide an entire cow.
| rekabis wrote:
| Pedantic Pete here: * The centigrade is
| capitalized when used after a number. There is also a
| singular glyph for the entire degree-centigrade convention: .
| * There are also superscript numerical characters to use with
| volumes, without having to use formatting: m3.
|
| UTF-8 is fun! As is automatic text replacement, once you have
| the appropriate triggers set up.
| Xylakant wrote:
| 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.
| aidenn0 wrote:
| I live in a climate where, for most of the year, the daily
| high-low temperature range includes 20C, so I'd like a whatever
| sized one is needed to average that out, and run most of the
| year without any active heating or cooling.
| Neywiny wrote:
| This is similar to nighthawkinlight's videos on phase change
| materials. It was very cool to see how his Ziploc bags of
| homemade goo helped regulate temperature.
| schiffern wrote:
| In this work the authors use a ceramic-coated extruded aluminum
| heat spreader to improve thermal conductivity through the bulk
| PCM, but I wonder if the graphite flake+powder additive
| demonstrated recently by Tech Ingredients[1] would be a viable
| alternative? It might need a stabilizer (thickener) to prevent
| the ingredients from separating.
|
| [1] https://www.youtube.com/watch?v=s-41UF02vrU
| syntaxing wrote:
| With the adoption of sodium batteries, I wouldn't be surprised if
| solar panel + sodium battery would outperform this system by a
| lot.
| belviewreview wrote:
| A heat pump gets more heat from a given amount of electricity
| than if the electricity is use for resistive heating. So the
| ideal design is solar cell + sodium battery + heat pump.
| coffeebeqn wrote:
| 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.
| mrguyorama wrote:
| 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 making it.
| Xylakant wrote:
| 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.
| karussell wrote:
| The problem with thermal solar panels is that you can use
| its heated water only if it gets warmer than the water in
| your system, which is not always the case, especially in
| winter.
|
| Compared to nearly 100% usable energy from normal solar
| panels.
|
| Furthermore if you have a heatpump you can convert this
| electric energy into heat energy with a factor of 3-5
| (COP).
| manmal wrote:
| Climates that need a hot tank of water to buffer for heat
| pumps, will not have meaningful solar panel output during
| winter. Or do you mean, just load the battery when electricity
| is cheap? A tank of water is 1k max, probably 10% of a sodium
| battery.
| Youden wrote:
| Even LFP batteries can work out better.
|
| I live in Switzerland where these are available. A Cowa 58 [0]
| costs CHF 4692 [1] and stores up to 13.5kWh. If you're heating
| the water with a heat pump, that's ~6kWh of electricity, so
| ~CHF 782/kWh.
|
| I'm in the process of installing a 33kWh battery and the
| battery + inverter cost CHF 13600 in total for just the
| hardware, so ~CHF 482/kWh.
|
| If you add solar panels, the inverter does double-duty
| producing AC from both the battery and the panels. The battery
| does double-duty producing both hot water and allowing you to
| use solar energy outside the times when the sun is shining.
|
| That said, having ordered a heat pump recently and being in the
| process of having solar + batteries installed, the amount of
| electrical work needed for the solar/battery install is
| substantially higher than was needed for the heat pump and
| here, the labour costs quite a lot, pushing the upfront cost
| difference even higher.
|
| I think that's where these heat storage things fit in: they
| have a much lower upfront cost. No matter how cheap the
| battery, for it to be useful in a Swiss residence, it needs to
| output a substantial amount of 3-phase power (3-phase is
| standard here, even in most apartments), which means you need
| to spend a couple thousand Francs on an inverter and electrical
| work. These heat storage devices are quite cheap and don't even
| need someone qualified to handle refrigerants, I imagine they
| could be installed by a normal plumber.
|
| That reduced upfront cost makes them far more accessible than
| electrical batteries, at least for now.
|
| [0]: https://www.cowa-
| ts.com/uploads/files/Dokumente/Datenblaette...
|
| [1]: https://nettoheizungshop.ch/Cowa-COMPACT-Cell-58
| Havoc wrote:
| Starting to get more optimistic about our energy future. Things
| seem to be tracking pretty good
| hedora wrote:
| I wonder if this can store any heat or just heat pump heat. If it
| can store any heat, it would help a lot to further reduce heating
| costs in our modern energy efficient house.
|
| Sometimes, in the winter, we get too much solar forcing, so if we
| don't heat all, it can be 85F in the day in the house, but 60-65
| at night. (We open the windows during the day, and don't always
| close them at exactly the right time at night.)
| direwolf20 wrote:
| Heat pump heat is just heat.
| karussell wrote:
| I think this can work and instead of that the heatpump pumps
| the heat into your house (when "solar is plenty") it would pump
| it into the storage. (I have a similar setup, but heat the
| water but of course this is rather limited)
|
| unrelated: a simple technical solution to your window problem
| would be home assistant and a few sensors to notify you when
| the windows are open too long or open when too cold inside.
| chickenimprint wrote:
| So it's a large version of those rechargeable hand-warmers?
| ZeroGravitas wrote:
| Yes, it's the same tech. There's been products on the market
| for a while even though this press release tries to spin it
| like it's new and linked to heat pumps.
| mrexroad wrote:
| IIRC BMW used to have a form of this in their cars about 25-30
| years back so that the hvac would be able to blow heat before
| the engine coolant was up to temp after sitting overnight.
| hnburnsy wrote:
| Related, TIL the US is effectively banning residential electric
| resistance water heaters in 2029, with heat pump water heaters
| being the only type that can meet the new standards. Users will
| see a 2-3x in cost difference and a 3 to 8 year payback on
| savings.
| cucumber3732842 wrote:
| Is that 2-3x before or after the plumber marks it up?
|
| What an exceptionally moronic thing to ban, the market solves
| this naturally. Resistance heaters are 100% efficient whatever
| fraction of the year is heating days. So if that's 1/2 the year
| and the water heater can't last 16yr because of water quality
| the heat pump heater will never pay you back.
|
| This reminds me a lot of the time some jerks in west coast
| desert states convinced the feds to regulate plumbing fixtures
| so that eastern "we take from the river and put back in the
| river" municipalities that have more water than they know what
| to do with have to suffer through low flow everything.
| hnburnsy wrote:
| Heat pump water heater (hybrid/HPWH, e.g., 50-65 gallon
| equivalent): Unit prices range from ~$1,500-$3,000+ (most
| common models $2,000-$2,500), with total installed costs
| $2,500-$5,000 (higher if electrical upgrades or space mods
| needed). Average retrofit/install often lands around
| $3,000-$4,000.
| sgc wrote:
| Electrical upgrades are almost always required, and price
| is more like 7k-9k around here. It's going to be seriously
| painful for a lot of people.
| dashundchen wrote:
| If you were in the market for an resistive electric heat
| pump, you likely had the service for it already. A heat
| pump version will almost always require less power.
| sgc wrote:
| My bad, read too quickly. I was thinking of the forced
| change over from gas water heaters, which is already
| happening in the California Bay Area and will only
| expand.
| quickthrowman wrote:
| If you currently have an electric resistive water heater,
| a heat pump water heater with the same heating capacity
| will use 3-4x less power, which means you can use a much
| smaller circuit.
|
| A 6kW 240V EWH uses 25A, it'll need #8 wire and a 35A or
| 40A breaker.
|
| An equivalent HPHW would use 1.5kW at 240V, or 6.25A. You
| can use #14s and a 15A breaker.
| drhike wrote:
| Ehh 120v models exist. My 65 gal runs fine on a standard
| 20a breaker.
| lm28469 wrote:
| And for small households they virtually never pay for
| themselves before they die or need expensive maintenance...
| It only makes sense if you use a lot of water or if your
| electricity is very expensive. In my case it's even worse,
| with solar panels and self sufficiency they literally
| cannot break even
| direwolf20 wrote:
| Is the heat pump heater taking heat from inside or outside
| the house?
| lm28469 wrote:
| Depends on the model, but a lot use the air from their own
| room, that's why they can't be installed in small rooms.
| Models pulling the heat from outside are more expensive and
| require more labor obviously, and they don't make a lot of
| sense for places that are bellow 0c multiple month a year
| as the COP will drop to 1.x and you will most likely need
| extra electricity for the anti frost cycles
| AlexandrB wrote:
| But dumping the waste cold air into the house when it's
| below 0C outside doesn't make much sense either.
| beAbU wrote:
| Heat pumps are effectively more than 100% efficient fyi. You
| put 1000W of electricity in, you get 2500W of heat going into
| the water. (Numbers are only illustrative)
|
| Running cost of heat pumps for heating is much much lower
| than resistive heating.
| pkulak wrote:
| If you're making plans 3 years out in the US, you're a fool.
| Sabinus wrote:
| That's a Biden-Harris administration action. What are the
| chances that Trump deletes it as a 'Democrat/WEF climate hoax
| con job' as soon as he's made aware of it?
| amazingman wrote:
| This is exactly the kind of thing government is for, even
| though it's missing the other half: subsidies. At the very
| least buying heat pumps for the next 5 years should be tax
| deductible. Even better: a $2000 or similar rebate.
| DangitBobby wrote:
| That's probably exactly what will happen.
| Energy property - Heat pumps and biomass stoves and boilers
| Heat pumps that meet or exceed the CEE highest efficiency
| tier, not including any advanced tier, in effect at the
| beginning of the year when the property is installed, and
| biomass stoves and boilers with a thermal efficiency rating
| of at least 75% qualify for a credit up to $2,000 per year.
| Costs may include labor for installation.
| Qualified property includes new: Electric or
| natural gas heat pumps Electric or natural gas heat
| pump water heaters Biomass stoves and boilers
|
| https://www.irs.gov/credits-deductions/energy-efficient-
| home...
| hnburnsy wrote:
| These are credits that only work if you have owe federal
| taxes and they cannot be carried forward. I've seen
| estimates that 40-45% of taxpayers owe 0 or close to 0.
| mrd999 wrote:
| Eh? If you have income you owe taxes, Uncle Sam just
| takes it before you even see it
| direwolf20 wrote:
| _Federal_ taxes specifically.
| JoblessWonder wrote:
| I think something like 25% of the population reports 0
| household income.
|
| (I don't understand the implications, it was just
| surprising when I heard that.)
| DangitBobby wrote:
| You can also get considerable rebates if your state
| participates in the "Inflation Reduction Act Home Energy
| Rebate Program", especially if you are low income. My
| state is still working on rolling it out but hopefully
| many people who can't use tax credits will be able to
| take advantage.
|
| https://www.tn.gov/environment/program-
| areas/energy/state-en...
| lm28469 wrote:
| > even though it's missing the other half: subsidies
|
| It's a double edged sword. In my country everyone bought
| pellet stoves because of the subsidies, hundreds of companies
| popped up, now that the subsidies have been phased out, 90%
| of the companies went down, with their support and warranties
| of course. The 10% that managed to survive increased their
| prices, which is easy to do once 90% of your competitors went
| bust
|
| People who thought they'd save money by having the government
| (their taxes really) pay the bill are waking up 5 years later
| with expensive maintenance, the first units are starting to
| fail and need to be replaced but they can't afford it without
| the 50%+ subsidies. Not to mention that the prices pellets
| goes up and down faster than your average shitcoin.
| rayiner wrote:
| The subsidies and rebates are a scam. The installers just
| jack up the prices until they capture the entire value of the
| rebate.
| amazingman wrote:
| This assumes the consumer doesn't know and can't look up
| the price of the hardware.
| rayiner wrote:
| The cost of installation vastly exceeds the cost of the
| hardware. And the installers will only warranty hardware
| you buy from them.
| seiferteric wrote:
| The problem is, energy use is only one part of the equation.
| Often times new appliances that are more efficient end up
| being more prone to breaking due to more complexity and
| companies trying to cut costs to meet a price point. This
| leads to people needing to replace there appliances much more
| often which really makes me question how much energy is
| actually saved if you include the energy used to produce
| them...
| reorder9695 wrote:
| I don't know about all heat pump systems, but mine at least
| requires the water tank to have a resistive immersion too. If
| the tank temperature gets below some threshold the heat pump
| refuses to work and turns the immersion on instead until it's
| warmed up enough.
| AlexandrB wrote:
| The problem with heat pumps replacing electric heaters (in cold
| climates) is that the waste cold air gets dumped into the house
| and needs to be heated again. Generally, electric water heaters
| are expensive to run compared to gas ones, so people use them
| in places a gas heater is not possible to install (e.g. no way
| to vent the exhaust). This also means that the heat pump would
| have nowhere to vent cold air.
|
| This kind of thing is why I don't like bans like this. The
| specifics matter a lot.
| chickenbig wrote:
| Perhaps I am missing something; this product already exists as
| the Sunamp Thermino.
|
| https://sunamp.com/en-gb/hot-water-solutions-thermino-range/
| ZeroGravitas wrote:
| 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.
| DrScientist wrote:
| 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.
| Xylakant wrote:
| 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.
| a_better_world wrote:
| 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.
| manmal wrote:
| Those are great for buffering only a few hours though.
| That would help avoid the expensive electricity price
| peaks.
| coryrc wrote:
| They don't work well with heat pumps. Heat pumps lose
| efficiency as the differential increases, so if you try to
| store heat in a tank, you quickly drop capacity and
| efficiency.
|
| Versus resistance, which is exactly as efficient at 0degC
| and 1000degC, and why those storage heaters used to make
| sense.
| vee-kay wrote:
| You are right in your analogy.
|
| Earth's oceans and seas act as giant heat sinks.
|
| And that means more trouble as global climate change
| impacts..
|
| https://www.earth.com/news/ocean-warming-broke-records-
| for-4...
| Nition wrote:
| It's funny how useful water is for power generation.
|
| There's heat storage as discussed here.
|
| Or you can store cold water in a reservoir as a giant
| battery, pumping it up high when you've got excess power, and
| letting it back down to generate hydroelectricity from it
| later.
|
| Or you can boil water to make steam that spins a turbine and
| use it to convert anything that can heat water (coal, oil,
| nuclear...) to electricity.
| themafia wrote:
| > It's funny how useful water is for power generation.
|
| It's gravity that does the generation. Water is convenient
| because it's weight per unit of volume is very high. Higher
| than most things we can get our hands on and it's also
| exceptionally safe.
|
| Since water isn't perfectly clean the main problem you face
| is corrosion. Which can take a great system and turn it
| into a nightmare of buried leaks and sudden problems.
|
| As far as our options go it _is_ really convenient.
| metalman wrote:
| the idea is theoreticaly good, but as it depends on sealing
| incompatable materials apart, there will be problems, and issues
| with disposing of failed units.Dry sand works as thermal storage
| without any issues, and only needs more space, competition will
| be stiff.Water also works, and ordinary off the floor systems can
| be used with no modifications. The only advantage the system will
| have is in places where space constraints combine with the desire
| for fancy solutions and ecobabble.
| animal531 wrote:
| Where I live we need a way to store and distribute cold as
| needed.
| burnt-resistor wrote:
| Stanford's cogen plant has an underground "ice cube" for
| campus/municipal chilled water infrastructure. Perhaps scaling
| something like that makes sense or perhaps to use an absorption
| heat pump (AHP) that can operate like and the reverse of an
| Einstein-Szilard refrigerator?
| burnt-resistor wrote:
| Private equity / Wall St. megacorps want to sell you complex
| systems that are fragile, unaffordable by the 99%, have short
| warranty periods, wear out quickly, require cloud logins and
| proprietary maintenance parts, and are mandated by law.
|
| GFL buying a simple resistive-heated clothes dryer, furnace, or
| tanked/tankless water heater in 2030.
| chankstein38 wrote:
| They should've used lasagna. You could be in a tundra heating it
| over a fire and, as long as you get it sufficiently and
| consistently hot, it'll still burn your mouth 20minutes later.
| cromka wrote:
| I was recently wondering if any particular type of food
| contributes to mouth cancer prevalence and I concluded that at
| the top of that list would be be lasagna and cherry tomato on a
| pizza/in a soup.
| Loughla wrote:
| And yet, if you make it like I do, there always manages to be
| one piece that is ice cold while the rest is shockingly hot.
| Even if you're start with warm ingredients.
|
| Physics does not apply to lasagna.
|
| Also I suck at making lasagna.
| jandrese wrote:
| 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.
| Tor3 wrote:
| 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.
| stuaxo wrote:
| What did you heat with before?
| manmal wrote:
| Certainly not gas or oil, which are still cheaper to heat
| with than heat pumps.
| snuxoll wrote:
| Installed mini-splits to replace the propane stove that
| heated my house, DIY job, so all it cost was the units
| themselves and some materials.
|
| Propane bill (no natural gas, town of 500) from Oct 24 to Feb
| 25 (installed the mini splits that month) was $1200, for just
| heating.
|
| My mini-splits are on a dedicated sub panel with an Emporia
| Vue 3 energy monitor. $604 in electricity consumption, and
| that includes air conditioning over the summer months.
|
| For what it's worth, our winter weather averages 25-35F with
| the occasional few days dipping to tens, single digits, and
| the occasional -10 freak; but these units just BARELY have a
| HSPF4 rating to classify as "cold climate" models. Still
| going to pay for themselves in 6 years without any tax
| credits, and 4 or so since I still installed them when they
| were available.
| matwood wrote:
| 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.
| spockz wrote:
| 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?
| toomuchtodo wrote:
| This is promising.
|
| https://www.pv-magazine.com/2026/01/29/samsung-releases-
| new-...
|
| > The South Korean giant [Samsung] said its new EHS All-in-
| One provides air heating and cooling, floor heating, and
| hot water from a single outdoor unit. It can supply hot
| water up to 65 C in below-zero weather.
|
| > Dubbed EHS All-in-One, the system provides air heating
| and cooling, floor heating, and hot water from a single
| outdoor unit. It is initially released for the European
| market, with a Korean rollout expected within a year. "It
| delivers stable performance across diverse weather
| conditions. It can supply hot water up to 65 C even in
| below-zero weather and is designed to operate heating even
| in severe cold down to -25 C," the company said in a
| statement. "The system also uses the R32 refrigerant, which
| has a substantially lower impact on global warming compared
| with the older R410A refrigerant."
| thunfischbrot wrote:
| Afaik heat-pumps in the EU can provide unlimited hot water-
| what am I missing?
| Y-bar wrote:
| Geothermal (and airbased) pumps theoretically do not have
| unlimited heating capacity. For example my pump (Daikin
| Altherma Geo 3) has a 180 litre water tank so it can "only"
| supply 180 litres hot water at 65 degrees Celsius and takes
| about a minute to heat two additional lites.
|
| So if I want to quickly scald myself in a 400 litre pool at
| fifty degrees I can't. But if I had a gas heater that would
| be possible!
| luckystarr wrote:
| While they are not as efficient or flexible, they are many
| times more efficient than resistive electric water heaters.
| I've installed one with in house air intake (due to
| construction reasons) in my house and it cooled down the
| basement by a few degrees (and removed air moisture as an
| added bonus). In summer the thermal capacity of the ground
| heats up the basement again, in winter it's a bit cooler, but
| it still works efficiently.
| stuaxo wrote:
| They use them a lot in Norway, it's hardly warm there.
| ortusdux wrote:
| I'm in the northern US and am very happy with mine. I self-
| installed with a county rebate, so the total cost was a
| Saturday and $700. My old electric unit was EPA rated for
| $450/year, and the new one has averaged $170/year over 4 years,
| so I've already broken even.
| gwbas1c wrote:
| You're about 20 years behind.
|
| My heat pump is working great at 0F. It's 7 years old.
| baggachipz wrote:
| heat pump for house !== heat pump for hot water
| karussell wrote:
| Why not?
| Youden wrote:
| I don't know what it's like where you're living but here in
| Switzerland it's completely normal to have one heat pump
| that does both. Here there's a lot of floor heating, which
| also uses water, so you usually just run one loop to the
| "boiler" (a water tank with a copper loop for the water
| from the heat pump to circulate through) and one through
| the floor and have a valve to switch which is running
| through the heat pump.
|
| I have one of these: https://cta.ch/en/private/products/ah-
| i-eco-innen
|
| I got it in October so most of the time I've had it has
| been <10C. It's produced 806.3 kWh of heating for hot water
| and 6587.2 kWh for the floor heating. It consumed 302.7 kWh
| and 1801.4 kWh respectively, for a COP of 2.66 and 3.66.
| gwbas1c wrote:
| There's a lot of different heating systems: If your heating
| system uses hot water at any point, (baseboards, hydro-air,
| underfloor, ect,) using a single heat pump makes a LOT of
| sense.
|
| Personally, I prefer an air-source heat pump hot water
| tank. It significantly dehumidifies my basement.
| themafia wrote:
| > government mandate will force enough demand that
| manufacturers can enjoy some economies of scale
|
| So you want the government to pick winners and you want to do
| business with a monopoly? This is the opposite of what you
| would want.
|
| If the product saves me money, and it's _actually_ better, I
| will buy it in a heartbeat. If you're involving the government
| it's because one of those things isn't true.
| lizknope wrote:
| Ask This Old House had an episode literally yesterday where
| they installed a \ solar-assisted split heat pump water heater.
| There is a component that goes on the outside of the house but
| not on the roof which simplifies installation.
|
| https://www.youtube.com/watch?v=uqyAWkXXt3A
|
| https://www.neshw.com/residential/solar-heat-pump-water-heat...
| danielovichdk wrote:
| Stones has the ability to store heat and keep cool.
|
| What's all this fuzz about ?
| Etheryte wrote:
| It's all about efficiency. You can store heat in anything, but
| the question is for how long and how much energy can you get
| back out later. The first part is easy and how we got ovens and
| stoves, the second part can be pretty tricky depending on your
| requirements. Large scale energy storage sometimes uses massive
| amounts of sand for example, but they heat it to hundreds of
| degrees which is not really feasible in most settings.
| ortusdux wrote:
| I was interested to learn about cold district heating recently,
| which is basically a municipal scale geothermal system.
|
| https://en.wikipedia.org/wiki/Cold_district_heating
| gwbas1c wrote:
| The article omits some critical details:
|
| It says this is both a "heat pump" and also "storage" AND says
| that it will run when electricity is cheap or plentiful. Thus:
|
| 1: Where does it pump the heat from? (Or is this not really a
| "heat pump" and instead is using resistive heating?)
|
| 2: How long does it store heat? Is this something that will store
| heat on a 24-48 hour basis, or will this store heat during the
| spring / fall when longer days mean extra power from residential
| solar, and then use the heat in the winter?
|
| 3: Is the unit itself "warm" when storing heat? Or is the heat
| stored in a purely chemical way and needs to run through a
| catalyst or similar to get it back?
|
| 4: Can this be scaled up for general domestic heating?
|
| ---
|
| Just an FYI: There are plenty of schemes with resistive electric
| water tanks to store heat when power is cheap.
| mike-the-mikado wrote:
| I would guess that is intended for a daily cycle, perhaps using
| air source heat pumps at times of day when the air temperatures
| are higher and electricity prices are lower, then using it as
| required.
|
| As it works on phase change (e.g. think of melting ice) heat is
| added (or removed) without changing the temperature of the
| store (which, I guess, might be hotter or colder than where the
| heat is extracted or used).
| IshKebab wrote:
| 1. The device is just storage. It would be paired with an air
| or ground source heat pump.
|
| 2. With good insulation you can easily store heat for a day
| which is all you need. You're never going to get close to
| storing summer heat for the winter. That's not impossible but
| not feasible for something this scale (and not cost effective
| at any scale).
|
| 3. You just heat it up and cool it down. There are no fancy
| chemical processes happening other than the phase change. It's
| exactly like a phase change hot/cold pack you can buy on
| Amazon.
|
| 4. I'm pretty sure this is designed for domestic heating...
|
| It's kind of an obvious idea tbh. I don't think they've done
| anything super innovative... They made an aluminium heat sink..
| butvacuum wrote:
| the only new thing- no matter how they do it- is putting it
| on residential instead of commercial or industrial installs.
|
| my childhood public school took us to some big commercial
| building- I think it was Sears' HQ- and they proudly showed
| us the huge blocks of ice providing chill during the day.
| Epa095 wrote:
| Not many numbers in there. I would be interested in some measure
| of energy and effect per volume, e.g how many kWh of heat are we
| talking about at e.g 1 liter, and how fast (kW) can it produce
| it?
___________________________________________________________________
(page generated 2026-02-02 23:00 UTC)