26 ms·

Heat pumps of the 1800s are becoming the technology of the future

399 points by adrian_mrd 4y ago

retrac 4y ago
> heat pumps: electrical devices Just to be pedantic, but not exactly. The typical design in a domestic heating unit, or refrigerator is mechanical. A fluid is pumped and cyclically compressed/expanded. While electric motors are usually used, they can be driven by any source of mechanical energy; driven directly by a combustion engine is not too unusual. There are also heat pump cycles that can be driven directly with heat. Refrigerators based on that are relatively common here in Canada in areas without reliable grid electricity. Usually a propane or natural gas flame. Thermoelectric coolers are actual electric heat pumps; directly moving heat across a semiconductor junction. Not very efficient and quite expensive practically. They're used in those USB drink coolers and to cool down lab equipment. Finding a high-efficiency thermoelectric material that works at normal temperatures and pressures is nearly as much of a Holy Grail as finding a high temperature superconductor.
- the_other 4y ago
  > Finding a high-efficiency thermoelectric material that works at normal temperatures and pressures is nearly as much of a Holy Grail as finding a high temperature superconductor. Are they two sides of the same problem?
  - deleted 4y ago
    [deleted]
  - fnordpiglet 4y ago
    No, TECs operates on a quirk related to semiconductor properties and are using electricity to move heat from one side to another but necessarily have resistance. Superconductors however are seeking zero electrical resistance. Current TECs produce 5x heat vs heat moved, and have a limited range of operation and a small range (30c) for the delta in heat between the two sides. I’ve been fascinated by TECs for years and I aspire to freeze CO2 with them, but it’s actually been really difficult to get cryogenic temperatures. You need to build a pyramid that has increasingly powerful TECs drawing heat away faster than it can accumulate. Even then I’m hitting walls in the -30c range because efficiency falls off a wall at both ends as you exceed the optimal ranges for the semiconductor materials.
- juujian 4y ago
  You are not adding anything to the conversation, but I still love pedantic comments like these.
  - NikolaNovak 4y ago
    Hmm, as somebody who knew a bit about heat pumps but not much, I did find it added to clarify/distinguish between the main mode of operation of heat pump, used to accomplish the actual heat transfer; and what power / mechanism is used to move the mechanical bits. I.e. an internal combustion engine implicitly uses some kind of burning fuel; if on the other hand you want to use electricity as energy source, it needs a different kind of engine entirely. But that, as I understand from the post, is not the case here - heat pump as described here can operate on same principle and look broadly similar in its core parts, whether powered by electricity or something else.
- zozbot234 4y ago
  Strictly speaking you don't need a phase change in the fluid for a viable heat pump; pressure change is enough albeit with worse efficiency. Even something as simple as a Stirling engine with forced circulation of the fluid works as a heat pump.
  - elil17 4y ago
    If you are referring to transcritical CO2 that is absolutely right. However you can't just use any pressure change in any gas, it would work but it would not be economically viable due to that inefficiency.
- ars 4y ago
  > There are also heat pump cycles that can be driven directly with heat. They are called https://en.wikipedia.org/wiki/Absorption_heat_pump https://en.wikipedia.org/wiki/Absorption_heat_pump But they are much less efficient that electrical ones, adding even a small amount of electricity to the cycle (even if the primary energy is heat) can dramatically improve efficiency.
- rootusrootus 4y ago
  > There are also heat pump cycles that can be driven directly with heat. Refrigerators based on that are relatively common here in Canada in areas without reliable grid electricity. Usually a propane or natural gas flame. Notably, the propane fridges used in RVs (which AFAIK usually use ammonia for the refrigerant) are extremely inefficient. They have the huge upside of requiring very little electrical power to operate, but would never be my choice if I wasn't tightly limited on electrical power.
  - namibj 4y ago
    They're inefficient because they skimp on a motor for a forced circulation pump. Otherwise, ammonia/water absorption chillers are quite efficient.
- crznp 4y ago
  As you said: a Peltier heat pump is a purely electrical device, so if you're using a broader definition of the term, it could be a variety of different types of devices. But that is the introductory paragraph, the author is defining what they mean by "heat pump": a device for heating a house which is powered by electricity. You could power it with something else, but the point is to replace natural gas furnaces.
  - usrusr 4y ago
    My mind parses the term "heat pump" as a device that works on temperature by compressing some medium. Works out just fine for most heat pumps, but not at all for e.g. the Peltier element which is about moving heat from one side to the oher ("pump") but does not involve compression at all.
- xpe 4y ago
  TLDR: for a heat pump, "electromechanical device" is more descriptive than "electrical device"
BooneJS 4y ago
When will air source heat pumps be ready for service in cold weather climates without gas backup?
- boplicity 4y ago
  They're available right now -- you can get ones that will heat from -30c. They're less efficient at colder temperatures, though.
- dabeeeenster 4y ago
  Just had a heat pump installed (Vaillant) - at -1 degrees outside I'm getting a COP of > 2.6. So they are ready.
  - sampo 4y ago
    > -1 degrees outside -1F is -18C -1C is 30F
    - ComputerGuru 4y ago
      They're from London, so it's the "not even cold but it's negative" rather than "actually cold and heat pumps aren't a good idea" measurement.
      - Freestyler_3 4y ago
        for those places where the scop is low, you have to drill for heat. If that's not possible then maybe a system where you can burn wood to suck the heat out of that.
- rr808 4y ago
  I feel a combination with a wood burning stove is best. Especially with the potential for power cuts.
  - Scoundreller 4y ago
nickpeterson 4y ago
Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc. When it’s freezing cold outside, it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated. Someone needs to make a standard for moving heat/cool through all appliances in a house…
- cinntaile 4y ago
  That sounds like it would be very expensive and error prone.
- retrac 4y ago
  > it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated The fridge is simply moving a little of the warmth in your room out of its box, and adding a little more warmth to the room in the process. You lose no heat from the room, which is what matters, really. It would be worse to dump the heat outside! At least in winter. The heat has to be removed in summer if you have air conditioning. In any case, an exterior heat exchanger and heat pump that can handle a wide exterior temperature is much more heavy duty. This could all end up being less efficient, in practice. House-scale heat pumps can efficiently move heat even from a freezing cold outside into a warm interior. Just as fridges can efficiently move heat from their cold interiors to a warm room.
  - ghettoCoder 4y ago
    I always joke that in winter all appliances are 100% efficient (I know they're not). Some look at me funny but the ones who pay the gas bill get usually get it.
    - tonyarkles 4y ago
      And incandescent light bulbs!
      - 4y ago
fasteddie31003 4y ago
I had a similar idea when I was designing a heating system for a mountain house I was planning on building. I was planning on primarily heating with an oversized wood stove. The excess heat the wood stove would produce would be captured by a heat pump inside the house with its coils in a 500 gallon tank of water that was well insulated. When the house needed heat you could run the heat pump in reverse or make a system that removed the insulation around the tank of water letting the heat out. I had a spreadsheet with the heat calculations. I think the water at 150F degrees had around a megawatt of energy stored in it and that could have heated the house for a couple weeks. I never ended building that house, but would love to build a system like this in the future.
- zdragnar 4y ago
  Outdoor wood boilers have been a thing for a long time. Back when I had mine, it kept the water at 180F. https://en.wikipedia.org/wiki/Outdoor_wood-fired_boiler https://en.wikipedia.org/wiki/Outdoor_wood-fired_boiler If you have enough sufficiently dry wood, downdraft gasification models burn extremely cleanly (they're effectively rocket stoves), but those models require a fair bit of maintenance, especially if your wood is slightly wet or green, because soot can quickly build up on the water envelope.
- PinguTS 4y ago
  I have about 1050 US gallons (4000 l) of water storage in my house. The very effective wooden carburettor heating system is heating up the water storage. Then you use the water storage for next days until you have to re-fire. That is a standard package provided by many companies from Austria and Germany.
mikewarot 4y ago
For our house, a ground loop heat pump would be best. A long slit trench, with the slinky style of coolant loop, in the back yard (away from utilities) could easily handle all our waste heat in the summer and source heat in the winter.
- ddalex 4y ago
  Wouldn't it be cheaper/easier to dig a well, fill it with tubing, and pouring concrete all over? The concrete being the constant-ish temperature heat reservoir ?
  - Nextgrid 4y ago
    Would concrete have sufficient thermal conductivity compared to damp soil?
  - richjdsmith 4y ago
    My parents built a new home a couple years ago. The property had a well despite being on city water. They have other homes with ground source heat pumps. When asking the geothermal contractor if they could use the same well borehole, the contractor said why don’t we just circulate the water and not bother the existing well. So that’s what they do - their geothermal system uses the well water, circulates it through the condenser, then sends the water back down into the ground.
    - voisin 4y ago
      This is fascinating! Is it possible to do this while utilizing the well for drinking water? I would assume so - it would just go through the condenser to exchange heat before being used elsewhere, and less would be pumped back down to the well?
jakedata 4y ago
In 2017 we installed a very efficient air-source heat pump and solar panels. My electrical utility offers 1:1 buyback of electricity so I am able to build up a credit in the summer and run the heat pump well into the fall and winter on that surplus. The system is sized for cooling the house which means that it is undersized for heating, but during cool fall and spring temperatures it operates satisfactorily as a heat source. Our fallback is the pre-existing gas boiler which is much simpler, more reliable and able to be powered by a small generator during our all-too-frequent power outages. If I am still in this home when the current heat pump fails I will seriously consider a ground-source system instead. The ability to operate during an extended power outage is a significant concern and I expect to always retain the gas boiler as a backup.
- macinjosh 4y ago
  Still waiting for one of these people who rave about their heat pump system to actually rely on it full time without a backup. Most folks could barely afford to replace an existing furnace in a place that has all the fixtures installed, much less pay to install a second one based on different setup, and then pay for maintaining two systems on top of everything else. It is absurd to think that this is a plausible way forward for anyone other than the wealthy tech enthusiast. Same thing for induction stoves. You all should start a club or something. The tech is not ready if you need a backup. I've lived in extreme cold climate areas and no gas furnace I've had has ever needed a backup.
  - dashundchen 4y ago
    I live in the snowy Great Lakes and I rely on a ground source heat pump and hot water heater full time. No issues at all. Cost similar to a high end gas furnace system when the tax credits were applied. Probably cheaper with air source systems today. I live in the city and don't lose power, but I'm hoping to eventually use a EV as a battery backup when the equipment is available and standards are finalized. A battery in a compact like the Chevy Bolt could power my heating system for several days. It's not like modern gas furnaces don't require power to operate. In a recent Buffalo blizzard power went out and many people with gas heating still froze and had their pipes burst.
macinjosh 4y ago
Half way through the article the author is touting how these can work in cold climates like Norway, then their example homeowner immediately states they have this but also they still have a furnace for when it actually is cold. Why do journalists try to pull crap like this? Contradictory information in the same paragraph!? If you have to have a backup it is _not_ a replacement and it will not get us off of carbon. Most people cannot afford a heat pump system much less a heat pump _and_ a furnace. Heat pumps seem great for moderate climates but it is not gonna happen up north where things actually get cold and stay cold for long periods of time. Anyone who actually has experienced this type of cold would run in the opposite direction of a heating technology that produces less warmth the colder it gets outside. Literally the opposite of what is needed for existence.
- motorogo 4y ago
  If you read the article carefully, it notes that part of the problem in some colder climates is a lack of home insulation. Norwegian homes are well-insulated and therefore very suitable for heat pumps. The home owner with the furnace was US-based, by the way. The author is not "pulling crap" because they point out the real experience of Norwegian home owners while also describing the diversity of heat pump installations and outcomes. They're actually being very honest.
- rainsford 4y ago
  A solution doesn't have to move us away from fossil fuels all by itself to be a useful piece of the puzzle. Even if heat pumps were only viable in places that don't regularly get super cold in the winter (which isn't true), that's a huge number of places covering a large portion of the population. A lot of the US, for example, gets hot enough in the summer that you want central air conditioning but also gets moderately cold in the winter. A heat pump system can cover you all year round with the same exact system. If you install a backup heat source, which can be electric by the way, that covers even more potential installation locations.
- timbit42 4y ago
  It's not that black or white. I only need a backup for my heat pumps for perhaps a week each winter. The heat pump still saves me 40% on my heating costs throughout the year. Also, Norway doesn't get as cold as you might think. They get some heat from the gulf stream in the Atlantic ocean like the UK does. Russia and Canada get a lot colder in their northern parts, like -40C quite often and sometimes even as low as -50C. Heat pumps aren't very viable below -25C, but work is ongoing to make the more efficient at lower temps.
LatteLazy 4y ago
Everyone is looking for an easy answer to climate change / energy costs / energy independence etc. But there isn't one. Fusion remains decades away, Fission is very expensive and unpopular, Most renewables are intermittent etc. Heat pumps are one more tech with very limited potential (range of temperatures, efficiency over that range, power output limits, need for a heat source, size, cost etc).
- wpietri 4y ago
  Wait, you are telling a bunch of technologists that no technology is perfect? Stop the presses! Which, dang it, are clearly also an imperfect technology if we have to stop them every time there's fresh news.
- Freestyler_3 4y ago
  I don't follow how heat pumps have limited potential. They have big potential. Its not a one size fits all solution, that's all.
- thomasjb 4y ago
  What's your perspective on sustainable biomass usage such as pollarding and coppicing, and bringing energy usage inline with that which can be fueled by them, in addition to small scale wind?
rini17 4y ago
Interesting! Do I understand correctly that the additional water storage just cycles between 0°C and below room temperature to further cool/preheat the coolant? Hard to believe it could have such a big effect. And how does it fit into existing setup? I can imagine it can be connected before water boiler to supply the lukewarm water.
renlo 4y ago
Wouldn't using a lake as a heat/cooling source cause "thermal pollution"? It's probably fine if a couple houses surrounding the lake use it, but if the technology begins mainstream enough to where everyone is using it, it could cause a lot of issues for the flora and fauna of that lake / downstream habitats.
- vestrigi 4y ago
  I think in the winter it would be fine to move heat from the lake to houses but in the summer it's worse. We're already having problems with lakes being too hot in the summer which results in evaporation, algae build-up and less oxygen. This also promotes invasive species. Of course, the question is at what scale we can build such systems and if that would raise water temperatures significantly. I am not a biologist.
PinguTS 4y ago
Sorry, but I don't see any novelty here. Everything described in the article is commercially available. At least here in Germany. Heat pumps are used to heat a storage container called buffer, a water container of 200l or more of water. This is used to run the heat pump when energy is cheap to warm up the buffer. That is for example in daytime when energy is available from the photovoltaic. If you don't have photovoltaic you can also have a good energy price when running this at night. Also the storage of the heat in summer is nothing new. These systems are also commercially available for years. It is only that they are so expansive that many companies have backed out of those. The idea here is that in summer time you heat up a big tank in the ground like with a thermal system on your roof. Then in winter time you use that "saved" energy to run the heat pump. At the end of the winter the water in the tank will likely be freezing. That state change of the water will give an additional energy boost, because it is the same amount of energy you need to boil water. All this is well known and working and commercially available for years.
- sschueller 4y ago
  This is like when Apple introduces some new feature that existed on Android for years and claims it as some sort of revolutionary thing. In this case it's just that the mainstream US has discovered heat pumps when they have been mainstream in Europe for many years.
  - dboreham 4y ago
    I lived in a townhouse in Santa Clara in the mid 1990s that had heat pump heating (combined with ac).
  - nemo44x 4y ago
    Millions of people have used them for years. They just weren’t as popular due to gas being cheaper and available everywhere. There’s been a bigger push the last 10 years as gas prices have gone up. So they’ve been there but it didn’t make sense to use. You have to remember that things like gas are much cheaper in the USA. There’s just more natural resources here.
- caf 4y ago
H4ZB7 4y ago
TIL heat pumps weren't invented in the last few years
fifteenforty 4y ago
In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units including installation. Payback time is about 3 years. The system is oversized, but enables excellent zoning and of course provides cooling which is a must on 40C/104F days. Why do they seem to be so much more expensive in the US?
- teruakohatu 4y ago
  > Ducts are dead. Ducted heatpumps are a thing here in NZ and make sense to me, not that I have used one. The heatpump sits in the roof and air is pushed into three or so rooms through ducts. If building a new house I think ducts would be the way to go.
  - fifteenforty 4y ago
    You have to think carefully about where you run the ducts. They can be a huge source of energy loss. 40% is the number quoted by the EPA. Most roofs in Australia still aren’t sealed. The air barrier and insulation barrier is the ceiling. The roof space itself is not insulated, so the ducts are exposed to extreme temperatures, thus destroying the efficiency. Here is just one article on it: https://newenergythinking.com/2018/10/20/dont-use-ducts/ https://newenergythinking.com/2018/10/20/dont-use-ducts/
    - teruakohatu 4y ago
      I hadn't considered that. My argument with split systems, at least how they are installed in NZ, is that they are usually installed in the main living area and if there is a second unit, in a corridor. So corridors are heated or cooled far hotter or colder than they need to be in order to heat/cool bedrooms.
      - deleted 4y ago
smm11 4y ago
Holding my breath that my firebreathing gas stove is actually okay with The Man.
post_break 4y ago
My dryer is a heat pump. The only issue is it takes a long time to dry my clothes, but the benefits are huge power use decrease, and so much more gentle on my clothes.
- vdfs 4y ago
  heat pump are also used to cool down your room/house
Lisa_Novak 4y ago
[dead]
phyzome 4y ago
> owners of drafty homes may need to take on the added cost of insulation when installing a heat pump Installing good insulation is also really important even if you're not using heat pumps! With bad insulation, you're wasting energy no matter what technology you're using.
- nemo44x 4y ago
  It’s not always possible. For instance old wood double hung sash windows require a weight box to work. Those boxes can’t really be insulated. And there’s a good chance you don’t want to replace the old windows (or possibly can’t due to historic restrictions) because they are a massive part of the homes character. Also insulating an old home (pre-WW2) could begin to introduce moisture issues in the walls that weren’t there the last 100+ years since the leakiness of the home would dry the structure. Last thing you want is for condensation and water vapor to build up in the insulation and then begin to rot the wood. Modern build have vapor barriers and airtight seals. I guess my point is to be careful with old structures without considering things. They were built the way they were because those were the materials we had (old growth wood!) and they were designed to function a certain way.
  - Sytten 4y ago
    On the contrary modern houses often rot because of the water barrier. Condensation gets trapped in the wall and it rots really fast. If you insulate your old house from the inside you wont have this issue. I spent the last 3 years remodelling at 1875 house and we opened all the walls to spray urethane foam. It sealed all the cracks between the wood beams but still leaves the exterior untouched to moisture can leave.
    - nemo44x 4y ago
      Yeah any house build in the 70’s, 80’s, or early 90’s might had issues with moisture. Water vapor in particular. Im not sure I’d spend the money (or desire the inconvenience) on a job like that on my old home. I’m not sure I’d make the money back in savings during my time here. But during a gutting, makes sense.
dv_dt 4y ago
Thermodynamics is eternal
EZ-Cheeze 4y ago
"Stuck at home during the first UK lockdown of the Covid-19 pandemic, the thermal engineer suddenly had all the time he needed to refine the efficiency of heat pumps" I've seen that story a few times now. The free time let a lot of innovation happen. Fuck jobs
twawaaay 4y ago
I am in constant bewilderment about all of the talk of saving electricity but still so few homes having a very basic device like heat exchanger. At its very simplest it is just a box where incoming air is being heated by outgoing air without both getting mixed. It is a bunch of pipes, radiators and two fans in a box. Whether you heat or cool your house, an open window is energy loss. The heat exchanger lets you keep your house nicely ventilated while reducing those losses due to ventilation by something like 90%.
- HellzStormer 4y ago
  Logically (and ideally), the incoming air and outgoing air would exchange heat until they are at the same temp, which would be in the middle. So I would not expect an efficiency higher than 50% unless there is some special tech I'm not aware?
  - twawaaay 4y ago
    Imagine you have two very long tubes joined thermally throughout their entire lengths. For the sake of simplicity, no energy is exchanged with the environment, only between the two fluids. The cold fluid will meet (thermally, in adjacent pipe) more and more hot other fluid and finally as it reaches the end it will meet the hot fluid at exactly the temperature it comes in. If the fluids are flowing slow enough and the thermal bond is good enough, the cold fluid can get heated up as close to the hot fluid temperature as you want. And the hot fluid will meet colder and colder other fluid until it reaches the coldest at the other side. The efficiency of heat exchanger could be as close to 100% as you want, in ideal world. In real world higher efficiency requires larger device and there is a point of diminishing returns. You also get other losses like mechanical losses due to need to pump fluids through pipes (with large surface area), due to need to have turbulent flow (to ensure mixing within pipes) and due to heat loss to the environment.
  - deleted 4y ago
    [deleted]
  - darken 4y ago
    According to Wikipedia, ERV (Energy Recovery Ventilators) can reach 90% efficiency via "modern low-cost gas-phase heat exchanger technology". https://en.wikipedia.org/wiki/Energy_recovery_ventilation https://en.wikipedia.org/wiki/Energy_recovery_ventilation I think another part of this is that there is generally a significant moisture content difference between hot and cool air, leading to some additional gains versus thinking in terms of air temperature alone.
eddsh1994 4y ago
People in the UK are talking about the risk of heat pump installations being in the tens of thousands & not possible everywhere. This is mostly from anti-green MPs. Anyone know what the facts are there?
- timbit42 4y ago
  There are some videos on this YT channel about that: https://www.youtube.com/@EverythingElectricShow https://www.youtube.com/@EverythingElectricShow
hbarka 4y ago
Replacing my conventional tea kettle water heater with a Sanden SanCO2 heat pump water heater. It uses CO2 (R744) as the refrigerant. https://www.smallplanetsupply.com/sanc02 https://www.smallplanetsupply.com/sanc02 https://r744.com/co2-heat-pump-water-heater-market-for-homes-growing-rapidly-in-south-australia/ https://r744.com/co2-heat-pump-water-heater-market-for-homes...
jonplackett 4y ago
> Lord Kelvin proposed using heat pump systems for space heating way back in 1852. The first heat pump was designed and built a few years later That’s the kind of speed we need if this is going to be any help before everything’s on fire anyway. From what I can tell (in / for the UK at least) heat pumps currently aren’t that great - my dad’s boiler just died and every plumber he spoke to said heat pumps kinda suck and to just get a nice new gas boiler…
- nerdface 4y ago
  Usually because those contractors have zero experience with heat pumps and want to sell you what they offer.
- zip1234 4y ago
  In the US have started seeing them for heating water but mainly for household use (showers, general water heating) and not for a boiler replacement.
- coder543 4y ago
  If the only research you did is secondhand word of mouth, I think you need to do a little more research. Heat pumps are extremely excellent, and have been for years. We've even reached the point where heat pumps are able to work effectively in places like North Dakota. For reference, the UK doesn't even have the concept of weather like that.
- Danieru 4y ago
  "I talked to a bunch of horse tamers and they say cars are just no good. So I bought another horse. I don't see all the hype" Similar issue in the states. HVAC specialist trash talking mini splits because a mini split's advantage of cheaper maintenance and install is meaningless to the HVAC specialist. Instead they only see the trade offs. Then they quote a bill as if installing a mini split requires a diploma and point out just how uneconomical the farce is.
  - jonplackett 4y ago
    This isn’t an appropriate analogy - the plumbers also fit the heat pumps. They just don’t recommend them
EricE 4y ago
I don't know where the heck all this extra electricity for heat pumps and electric car charging is going to come from. In CA if you get a slightly hotter than average summer their electrical grid goes into chaos. Get a slightly colder than normal winter and the north east and central grid freaks out. I'm all for transitioning to renewable energy (nuclear makes the most sense if you take emotion and bullshit out of it) but we have a long way to go before we can just ditch gasoline, diesel and natural gas any time soon. Heck how many millions of US homes will have to get their electrical service upgraded, never mind the base electric infrastructure?
- devwastaken 4y ago
  A heat pump operates at 2x to 4x the power efficiency as compared to resistive heating. Many places are unfortunately only doing resistive heating because of cheap install cost. If we can replace that with a heat pump that's a big win for everyone.
fjfaase 4y ago
I have wondered whether using a small windmill (on the roof) to power the compressor directly could work. This to prevent the energy loss of converting mechanical energy to electrical and electrical to mechanical again. Combining this with a heat/cold storage which is filled there is a lot of wind to be used when there is less, seems to be good idea as well.
- MaKey 4y ago
  The energy those small windmills could generate on a typical house roof is in the double digit kWh territory per year, so I doubt you'd be able to power a compressor with one.
hnbad 4y ago
It's astonishing to me to see an article present heat pumps as innovative new tech and insulation as something worth looking into. In Germany if you want to build a house, almost every construction company will default to some variant of heat pumps. Actual plumbing companies are more likely to recommend an air-sourced heat pump, prefab construction companies seem to have taken a liking to air-air heat pumps (which like air conditioners pump hot air into rooms rather than running hot water pipes through the building for heating) but either way it'll be a heat pump of some kind or another. Also not only is there a legal minimum requirement for insulation but all grants and subsidies (when available) specify a minimum standard for insulation that must be met. Note that in new constructions they're also combined with a ventilation system to prevent mould and improve air quality. In older buildings retrofitted with modern insulation, tenants are usually instructed on how to vent by opening the windows. On the other hand, air conditioning is almost unheard of compared to the US outside retail. Even office buildings usually only have desk fans.
conaclos 4y ago
Two weeks ago, we talked about thermo-acoustic heat pumps on HN [1]. This could interest most of the readers of this thread. [1] https://news.ycombinator.com/item?id=34233719 https://news.ycombinator.com/item?id=34233719
dghughes 4y ago
I'd prefer a heat pump that uses ducts I hate the look of ductless heat pump that giant eyesore lump on the wall. But ducted are not as efficient compared to ductless due to the long runs of ducts and cold attics (even if ducts insulated). Plus my province won't give any rebates for ducted only ductless. Even better would be ground-source heat pump. But still I'd prefer ducts I think you'd have to with a ground source system.

399 points by adrian_mrd 4y ago

> heat pumps: electrical devices Just to be pedantic, but not exactly. The typical design in a domestic heating unit, or refrigerator is mechanical. A fluid is pumped and cyclically compressed/expanded. While electric motors are usually used, they can be driven by any source of mechanical energy; driven directly by a combustion engine is not too unusual. There are also heat pump cycles that can be driven directly with heat. Refrigerators based on that are relatively common here in Canada in areas without reliable grid electricity. Usually a propane or natural gas flame. Thermoelectric coolers are actual electric heat pumps; directly moving heat across a semiconductor junction. Not very efficient and quite expensive practically. They're used in those USB drink coolers and to cool down lab equipment. Finding a high-efficiency thermoelectric material that works at normal temperatures and pressures is nearly as much of a Holy Grail as finding a high temperature superconductor.

the_other 4y ago
> Finding a high-efficiency thermoelectric material that works at normal temperatures and pressures is nearly as much of a Holy Grail as finding a high temperature superconductor. Are they two sides of the same problem?
- deleted 4y ago
  [deleted]
- fnordpiglet 4y ago
  No, TECs operates on a quirk related to semiconductor properties and are using electricity to move heat from one side to another but necessarily have resistance. Superconductors however are seeking zero electrical resistance. Current TECs produce 5x heat vs heat moved, and have a limited range of operation and a small range (30c) for the delta in heat between the two sides. I’ve been fascinated by TECs for years and I aspire to freeze CO2 with them, but it’s actually been really difficult to get cryogenic temperatures. You need to build a pyramid that has increasingly powerful TECs drawing heat away faster than it can accumulate. Even then I’m hitting walls in the -30c range because efficiency falls off a wall at both ends as you exceed the optimal ranges for the semiconductor materials.
juujian 4y ago
You are not adding anything to the conversation, but I still love pedantic comments like these.
- NikolaNovak 4y ago
  Hmm, as somebody who knew a bit about heat pumps but not much, I did find it added to clarify/distinguish between the main mode of operation of heat pump, used to accomplish the actual heat transfer; and what power / mechanism is used to move the mechanical bits. I.e. an internal combustion engine implicitly uses some kind of burning fuel; if on the other hand you want to use electricity as energy source, it needs a different kind of engine entirely. But that, as I understand from the post, is not the case here - heat pump as described here can operate on same principle and look broadly similar in its core parts, whether powered by electricity or something else.
zozbot234 4y ago
Strictly speaking you don't need a phase change in the fluid for a viable heat pump; pressure change is enough albeit with worse efficiency. Even something as simple as a Stirling engine with forced circulation of the fluid works as a heat pump.
- elil17 4y ago
  If you are referring to transcritical CO2 that is absolutely right. However you can't just use any pressure change in any gas, it would work but it would not be economically viable due to that inefficiency.
ars 4y ago
> There are also heat pump cycles that can be driven directly with heat. They are called https://en.wikipedia.org/wiki/Absorption_heat_pump https://en.wikipedia.org/wiki/Absorption_heat_pump But they are much less efficient that electrical ones, adding even a small amount of electricity to the cycle (even if the primary energy is heat) can dramatically improve efficiency.
rootusrootus 4y ago
> There are also heat pump cycles that can be driven directly with heat. Refrigerators based on that are relatively common here in Canada in areas without reliable grid electricity. Usually a propane or natural gas flame. Notably, the propane fridges used in RVs (which AFAIK usually use ammonia for the refrigerant) are extremely inefficient. They have the huge upside of requiring very little electrical power to operate, but would never be my choice if I wasn't tightly limited on electrical power.
- namibj 4y ago
  They're inefficient because they skimp on a motor for a forced circulation pump. Otherwise, ammonia/water absorption chillers are quite efficient.
crznp 4y ago
As you said: a Peltier heat pump is a purely electrical device, so if you're using a broader definition of the term, it could be a variety of different types of devices. But that is the introductory paragraph, the author is defining what they mean by "heat pump": a device for heating a house which is powered by electricity. You could power it with something else, but the point is to replace natural gas furnaces.
- usrusr 4y ago
  My mind parses the term "heat pump" as a device that works on temperature by compressing some medium. Works out just fine for most heat pumps, but not at all for e.g. the Peltier element which is about moving heat from one side to the oher ("pump") but does not involve compression at all.
xpe 4y ago
TLDR: for a heat pump, "electromechanical device" is more descriptive than "electrical device"

BooneJS 4y ago

When will air source heat pumps be ready for service in cold weather climates without gas backup?

boplicity 4y ago
They're available right now -- you can get ones that will heat from -30c. They're less efficient at colder temperatures, though.
dabeeeenster 4y ago
Just had a heat pump installed (Vaillant) - at -1 degrees outside I'm getting a COP of > 2.6. So they are ready.
- sampo 4y ago
  > -1 degrees outside -1F is -18C -1C is 30F
  - ComputerGuru 4y ago
    They're from London, so it's the "not even cold but it's negative" rather than "actually cold and heat pumps aren't a good idea" measurement.
    - Freestyler_3 4y ago
      for those places where the scop is low, you have to drill for heat. If that's not possible then maybe a system where you can burn wood to suck the heat out of that.
rr808 4y ago
I feel a combination with a wood burning stove is best. Especially with the potential for power cuts.
- Scoundreller 4y ago

nickpeterson 4y ago

Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc. When it’s freezing cold outside, it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated. Someone needs to make a standard for moving heat/cool through all appliances in a house…

cinntaile 4y ago
That sounds like it would be very expensive and error prone.
retrac 4y ago
> it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated The fridge is simply moving a little of the warmth in your room out of its box, and adding a little more warmth to the room in the process. You lose no heat from the room, which is what matters, really. It would be worse to dump the heat outside! At least in winter. The heat has to be removed in summer if you have air conditioning. In any case, an exterior heat exchanger and heat pump that can handle a wide exterior temperature is much more heavy duty. This could all end up being less efficient, in practice. House-scale heat pumps can efficiently move heat even from a freezing cold outside into a warm interior. Just as fridges can efficiently move heat from their cold interiors to a warm room.
- ghettoCoder 4y ago
  I always joke that in winter all appliances are 100% efficient (I know they're not). Some look at me funny but the ones who pay the gas bill get usually get it.
  - tonyarkles 4y ago
    And incandescent light bulbs!
    - 4y ago

fasteddie31003 4y ago

I had a similar idea when I was designing a heating system for a mountain house I was planning on building. I was planning on primarily heating with an oversized wood stove. The excess heat the wood stove would produce would be captured by a heat pump inside the house with its coils in a 500 gallon tank of water that was well insulated. When the house needed heat you could run the heat pump in reverse or make a system that removed the insulation around the tank of water letting the heat out. I had a spreadsheet with the heat calculations. I think the water at 150F degrees had around a megawatt of energy stored in it and that could have heated the house for a couple weeks. I never ended building that house, but would love to build a system like this in the future.

zdragnar 4y ago
Outdoor wood boilers have been a thing for a long time. Back when I had mine, it kept the water at 180F. https://en.wikipedia.org/wiki/Outdoor_wood-fired_boiler https://en.wikipedia.org/wiki/Outdoor_wood-fired_boiler If you have enough sufficiently dry wood, downdraft gasification models burn extremely cleanly (they're effectively rocket stoves), but those models require a fair bit of maintenance, especially if your wood is slightly wet or green, because soot can quickly build up on the water envelope.
PinguTS 4y ago
I have about 1050 US gallons (4000 l) of water storage in my house. The very effective wooden carburettor heating system is heating up the water storage. Then you use the water storage for next days until you have to re-fire. That is a standard package provided by many companies from Austria and Germany.

mikewarot 4y ago

For our house, a ground loop heat pump would be best. A long slit trench, with the slinky style of coolant loop, in the back yard (away from utilities) could easily handle all our waste heat in the summer and source heat in the winter.

ddalex 4y ago
Wouldn't it be cheaper/easier to dig a well, fill it with tubing, and pouring concrete all over? The concrete being the constant-ish temperature heat reservoir ?
- Nextgrid 4y ago
  Would concrete have sufficient thermal conductivity compared to damp soil?
- richjdsmith 4y ago
  My parents built a new home a couple years ago. The property had a well despite being on city water. They have other homes with ground source heat pumps. When asking the geothermal contractor if they could use the same well borehole, the contractor said why don’t we just circulate the water and not bother the existing well. So that’s what they do - their geothermal system uses the well water, circulates it through the condenser, then sends the water back down into the ground.
  - voisin 4y ago
    This is fascinating! Is it possible to do this while utilizing the well for drinking water? I would assume so - it would just go through the condenser to exchange heat before being used elsewhere, and less would be pumped back down to the well?

jakedata 4y ago

In 2017 we installed a very efficient air-source heat pump and solar panels. My electrical utility offers 1:1 buyback of electricity so I am able to build up a credit in the summer and run the heat pump well into the fall and winter on that surplus. The system is sized for cooling the house which means that it is undersized for heating, but during cool fall and spring temperatures it operates satisfactorily as a heat source. Our fallback is the pre-existing gas boiler which is much simpler, more reliable and able to be powered by a small generator during our all-too-frequent power outages. If I am still in this home when the current heat pump fails I will seriously consider a ground-source system instead. The ability to operate during an extended power outage is a significant concern and I expect to always retain the gas boiler as a backup.

macinjosh 4y ago
Still waiting for one of these people who rave about their heat pump system to actually rely on it full time without a backup. Most folks could barely afford to replace an existing furnace in a place that has all the fixtures installed, much less pay to install a second one based on different setup, and then pay for maintaining two systems on top of everything else. It is absurd to think that this is a plausible way forward for anyone other than the wealthy tech enthusiast. Same thing for induction stoves. You all should start a club or something. The tech is not ready if you need a backup. I've lived in extreme cold climate areas and no gas furnace I've had has ever needed a backup.
- dashundchen 4y ago
  I live in the snowy Great Lakes and I rely on a ground source heat pump and hot water heater full time. No issues at all. Cost similar to a high end gas furnace system when the tax credits were applied. Probably cheaper with air source systems today. I live in the city and don't lose power, but I'm hoping to eventually use a EV as a battery backup when the equipment is available and standards are finalized. A battery in a compact like the Chevy Bolt could power my heating system for several days. It's not like modern gas furnaces don't require power to operate. In a recent Buffalo blizzard power went out and many people with gas heating still froze and had their pipes burst.

macinjosh 4y ago

Half way through the article the author is touting how these can work in cold climates like Norway, then their example homeowner immediately states they have this but also they still have a furnace for when it actually is cold. Why do journalists try to pull crap like this? Contradictory information in the same paragraph!? If you have to have a backup it is _not_ a replacement and it will not get us off of carbon. Most people cannot afford a heat pump system much less a heat pump _and_ a furnace. Heat pumps seem great for moderate climates but it is not gonna happen up north where things actually get cold and stay cold for long periods of time. Anyone who actually has experienced this type of cold would run in the opposite direction of a heating technology that produces less warmth the colder it gets outside. Literally the opposite of what is needed for existence.

motorogo 4y ago
If you read the article carefully, it notes that part of the problem in some colder climates is a lack of home insulation. Norwegian homes are well-insulated and therefore very suitable for heat pumps. The home owner with the furnace was US-based, by the way. The author is not "pulling crap" because they point out the real experience of Norwegian home owners while also describing the diversity of heat pump installations and outcomes. They're actually being very honest.
rainsford 4y ago
A solution doesn't have to move us away from fossil fuels all by itself to be a useful piece of the puzzle. Even if heat pumps were only viable in places that don't regularly get super cold in the winter (which isn't true), that's a huge number of places covering a large portion of the population. A lot of the US, for example, gets hot enough in the summer that you want central air conditioning but also gets moderately cold in the winter. A heat pump system can cover you all year round with the same exact system. If you install a backup heat source, which can be electric by the way, that covers even more potential installation locations.
timbit42 4y ago
It's not that black or white. I only need a backup for my heat pumps for perhaps a week each winter. The heat pump still saves me 40% on my heating costs throughout the year. Also, Norway doesn't get as cold as you might think. They get some heat from the gulf stream in the Atlantic ocean like the UK does. Russia and Canada get a lot colder in their northern parts, like -40C quite often and sometimes even as low as -50C. Heat pumps aren't very viable below -25C, but work is ongoing to make the more efficient at lower temps.

LatteLazy 4y ago

Everyone is looking for an easy answer to climate change / energy costs / energy independence etc. But there isn't one. Fusion remains decades away, Fission is very expensive and unpopular, Most renewables are intermittent etc. Heat pumps are one more tech with very limited potential (range of temperatures, efficiency over that range, power output limits, need for a heat source, size, cost etc).

wpietri 4y ago
Wait, you are telling a bunch of technologists that no technology is perfect? Stop the presses! Which, dang it, are clearly also an imperfect technology if we have to stop them every time there's fresh news.
Freestyler_3 4y ago
I don't follow how heat pumps have limited potential. They have big potential. Its not a one size fits all solution, that's all.
thomasjb 4y ago
What's your perspective on sustainable biomass usage such as pollarding and coppicing, and bringing energy usage inline with that which can be fueled by them, in addition to small scale wind?

rini17 4y ago

Interesting! Do I understand correctly that the additional water storage just cycles between 0°C and below room temperature to further cool/preheat the coolant? Hard to believe it could have such a big effect. And how does it fit into existing setup? I can imagine it can be connected before water boiler to supply the lukewarm water.

renlo 4y ago

Wouldn't using a lake as a heat/cooling source cause "thermal pollution"? It's probably fine if a couple houses surrounding the lake use it, but if the technology begins mainstream enough to where everyone is using it, it could cause a lot of issues for the flora and fauna of that lake / downstream habitats.

vestrigi 4y ago
I think in the winter it would be fine to move heat from the lake to houses but in the summer it's worse. We're already having problems with lakes being too hot in the summer which results in evaporation, algae build-up and less oxygen. This also promotes invasive species. Of course, the question is at what scale we can build such systems and if that would raise water temperatures significantly. I am not a biologist.

PinguTS 4y ago

Sorry, but I don't see any novelty here. Everything described in the article is commercially available. At least here in Germany. Heat pumps are used to heat a storage container called buffer, a water container of 200l or more of water. This is used to run the heat pump when energy is cheap to warm up the buffer. That is for example in daytime when energy is available from the photovoltaic. If you don't have photovoltaic you can also have a good energy price when running this at night. Also the storage of the heat in summer is nothing new. These systems are also commercially available for years. It is only that they are so expansive that many companies have backed out of those. The idea here is that in summer time you heat up a big tank in the ground like with a thermal system on your roof. Then in winter time you use that "saved" energy to run the heat pump. At the end of the winter the water in the tank will likely be freezing. That state change of the water will give an additional energy boost, because it is the same amount of energy you need to boil water. All this is well known and working and commercially available for years.

sschueller 4y ago
This is like when Apple introduces some new feature that existed on Android for years and claims it as some sort of revolutionary thing. In this case it's just that the mainstream US has discovered heat pumps when they have been mainstream in Europe for many years.
- dboreham 4y ago
  I lived in a townhouse in Santa Clara in the mid 1990s that had heat pump heating (combined with ac).
- nemo44x 4y ago
  Millions of people have used them for years. They just weren’t as popular due to gas being cheaper and available everywhere. There’s been a bigger push the last 10 years as gas prices have gone up. So they’ve been there but it didn’t make sense to use. You have to remember that things like gas are much cheaper in the USA. There’s just more natural resources here.
caf 4y ago

H4ZB7 4y ago

TIL heat pumps weren't invented in the last few years

fifteenforty 4y ago

In a house I own in Melbourne, Australia, I just replaced an old gas central heating system with 3 new top of the line Daikin mini split heat pumps. The new units can heat the entire house for the same amount of electrical energy that was used to run the FAN in the old gas unit. They are crazy efficient. Ducts are dead. The Daikin Alira X is the gold-plated option and cost $8k AUD for 2x2.5kw and 1x7.1kw units including installation. Payback time is about 3 years. The system is oversized, but enables excellent zoning and of course provides cooling which is a must on 40C/104F days. Why do they seem to be so much more expensive in the US?

teruakohatu 4y ago
> Ducts are dead. Ducted heatpumps are a thing here in NZ and make sense to me, not that I have used one. The heatpump sits in the roof and air is pushed into three or so rooms through ducts. If building a new house I think ducts would be the way to go.
- fifteenforty 4y ago
  You have to think carefully about where you run the ducts. They can be a huge source of energy loss. 40% is the number quoted by the EPA. Most roofs in Australia still aren’t sealed. The air barrier and insulation barrier is the ceiling. The roof space itself is not insulated, so the ducts are exposed to extreme temperatures, thus destroying the efficiency. Here is just one article on it: https://newenergythinking.com/2018/10/20/dont-use-ducts/ https://newenergythinking.com/2018/10/20/dont-use-ducts/
  - teruakohatu 4y ago
    I hadn't considered that. My argument with split systems, at least how they are installed in NZ, is that they are usually installed in the main living area and if there is a second unit, in a corridor. So corridors are heated or cooled far hotter or colder than they need to be in order to heat/cool bedrooms.
    - deleted 4y ago

smm11 4y ago

Holding my breath that my firebreathing gas stove is actually okay with The Man.

post_break 4y ago

My dryer is a heat pump. The only issue is it takes a long time to dry my clothes, but the benefits are huge power use decrease, and so much more gentle on my clothes.

vdfs 4y ago
heat pump are also used to cool down your room/house

Lisa_Novak 4y ago

[dead]

phyzome 4y ago

> owners of drafty homes may need to take on the added cost of insulation when installing a heat pump Installing good insulation is also really important even if you're not using heat pumps! With bad insulation, you're wasting energy no matter what technology you're using.

nemo44x 4y ago
It’s not always possible. For instance old wood double hung sash windows require a weight box to work. Those boxes can’t really be insulated. And there’s a good chance you don’t want to replace the old windows (or possibly can’t due to historic restrictions) because they are a massive part of the homes character. Also insulating an old home (pre-WW2) could begin to introduce moisture issues in the walls that weren’t there the last 100+ years since the leakiness of the home would dry the structure. Last thing you want is for condensation and water vapor to build up in the insulation and then begin to rot the wood. Modern build have vapor barriers and airtight seals. I guess my point is to be careful with old structures without considering things. They were built the way they were because those were the materials we had (old growth wood!) and they were designed to function a certain way.
- Sytten 4y ago
  On the contrary modern houses often rot because of the water barrier. Condensation gets trapped in the wall and it rots really fast. If you insulate your old house from the inside you wont have this issue. I spent the last 3 years remodelling at 1875 house and we opened all the walls to spray urethane foam. It sealed all the cracks between the wood beams but still leaves the exterior untouched to moisture can leave.
  - nemo44x 4y ago
    Yeah any house build in the 70’s, 80’s, or early 90’s might had issues with moisture. Water vapor in particular. Im not sure I’d spend the money (or desire the inconvenience) on a job like that on my old home. I’m not sure I’d make the money back in savings during my time here. But during a gutting, makes sense.

dv_dt 4y ago

Thermodynamics is eternal

EZ-Cheeze 4y ago

"Stuck at home during the first UK lockdown of the Covid-19 pandemic, the thermal engineer suddenly had all the time he needed to refine the efficiency of heat pumps" I've seen that story a few times now. The free time let a lot of innovation happen. Fuck jobs

twawaaay 4y ago

I am in constant bewilderment about all of the talk of saving electricity but still so few homes having a very basic device like heat exchanger. At its very simplest it is just a box where incoming air is being heated by outgoing air without both getting mixed. It is a bunch of pipes, radiators and two fans in a box. Whether you heat or cool your house, an open window is energy loss. The heat exchanger lets you keep your house nicely ventilated while reducing those losses due to ventilation by something like 90%.

HellzStormer 4y ago
Logically (and ideally), the incoming air and outgoing air would exchange heat until they are at the same temp, which would be in the middle. So I would not expect an efficiency higher than 50% unless there is some special tech I'm not aware?
- twawaaay 4y ago
  Imagine you have two very long tubes joined thermally throughout their entire lengths. For the sake of simplicity, no energy is exchanged with the environment, only between the two fluids. The cold fluid will meet (thermally, in adjacent pipe) more and more hot other fluid and finally as it reaches the end it will meet the hot fluid at exactly the temperature it comes in. If the fluids are flowing slow enough and the thermal bond is good enough, the cold fluid can get heated up as close to the hot fluid temperature as you want. And the hot fluid will meet colder and colder other fluid until it reaches the coldest at the other side. The efficiency of heat exchanger could be as close to 100% as you want, in ideal world. In real world higher efficiency requires larger device and there is a point of diminishing returns. You also get other losses like mechanical losses due to need to pump fluids through pipes (with large surface area), due to need to have turbulent flow (to ensure mixing within pipes) and due to heat loss to the environment.
- deleted 4y ago
  [deleted]
- darken 4y ago
  According to Wikipedia, ERV (Energy Recovery Ventilators) can reach 90% efficiency via "modern low-cost gas-phase heat exchanger technology". https://en.wikipedia.org/wiki/Energy_recovery_ventilation https://en.wikipedia.org/wiki/Energy_recovery_ventilation I think another part of this is that there is generally a significant moisture content difference between hot and cool air, leading to some additional gains versus thinking in terms of air temperature alone.

eddsh1994 4y ago

People in the UK are talking about the risk of heat pump installations being in the tens of thousands & not possible everywhere. This is mostly from anti-green MPs. Anyone know what the facts are there?

timbit42 4y ago
There are some videos on this YT channel about that: https://www.youtube.com/@EverythingElectricShow https://www.youtube.com/@EverythingElectricShow

hbarka 4y ago

Replacing my conventional tea kettle water heater with a Sanden SanCO2 heat pump water heater. It uses CO2 (R744) as the refrigerant. https://www.smallplanetsupply.com/sanc02 https://www.smallplanetsupply.com/sanc02 https://r744.com/co2-heat-pump-water-heater-market-for-homes-growing-rapidly-in-south-australia/ https://r744.com/co2-heat-pump-water-heater-market-for-homes...

jonplackett 4y ago

> Lord Kelvin proposed using heat pump systems for space heating way back in 1852. The first heat pump was designed and built a few years later That’s the kind of speed we need if this is going to be any help before everything’s on fire anyway. From what I can tell (in / for the UK at least) heat pumps currently aren’t that great - my dad’s boiler just died and every plumber he spoke to said heat pumps kinda suck and to just get a nice new gas boiler…

nerdface 4y ago
Usually because those contractors have zero experience with heat pumps and want to sell you what they offer.
zip1234 4y ago
In the US have started seeing them for heating water but mainly for household use (showers, general water heating) and not for a boiler replacement.
coder543 4y ago
If the only research you did is secondhand word of mouth, I think you need to do a little more research. Heat pumps are extremely excellent, and have been for years. We've even reached the point where heat pumps are able to work effectively in places like North Dakota. For reference, the UK doesn't even have the concept of weather like that.
Danieru 4y ago
"I talked to a bunch of horse tamers and they say cars are just no good. So I bought another horse. I don't see all the hype" Similar issue in the states. HVAC specialist trash talking mini splits because a mini split's advantage of cheaper maintenance and install is meaningless to the HVAC specialist. Instead they only see the trade offs. Then they quote a bill as if installing a mini split requires a diploma and point out just how uneconomical the farce is.
- jonplackett 4y ago
  This isn’t an appropriate analogy - the plumbers also fit the heat pumps. They just don’t recommend them

EricE 4y ago

I don't know where the heck all this extra electricity for heat pumps and electric car charging is going to come from. In CA if you get a slightly hotter than average summer their electrical grid goes into chaos. Get a slightly colder than normal winter and the north east and central grid freaks out. I'm all for transitioning to renewable energy (nuclear makes the most sense if you take emotion and bullshit out of it) but we have a long way to go before we can just ditch gasoline, diesel and natural gas any time soon. Heck how many millions of US homes will have to get their electrical service upgraded, never mind the base electric infrastructure?

devwastaken 4y ago
A heat pump operates at 2x to 4x the power efficiency as compared to resistive heating. Many places are unfortunately only doing resistive heating because of cheap install cost. If we can replace that with a heat pump that's a big win for everyone.

fjfaase 4y ago

I have wondered whether using a small windmill (on the roof) to power the compressor directly could work. This to prevent the energy loss of converting mechanical energy to electrical and electrical to mechanical again. Combining this with a heat/cold storage which is filled there is a lot of wind to be used when there is less, seems to be good idea as well.

MaKey 4y ago
The energy those small windmills could generate on a typical house roof is in the double digit kWh territory per year, so I doubt you'd be able to power a compressor with one.

hnbad 4y ago

It's astonishing to me to see an article present heat pumps as innovative new tech and insulation as something worth looking into. In Germany if you want to build a house, almost every construction company will default to some variant of heat pumps. Actual plumbing companies are more likely to recommend an air-sourced heat pump, prefab construction companies seem to have taken a liking to air-air heat pumps (which like air conditioners pump hot air into rooms rather than running hot water pipes through the building for heating) but either way it'll be a heat pump of some kind or another. Also not only is there a legal minimum requirement for insulation but all grants and subsidies (when available) specify a minimum standard for insulation that must be met. Note that in new constructions they're also combined with a ventilation system to prevent mould and improve air quality. In older buildings retrofitted with modern insulation, tenants are usually instructed on how to vent by opening the windows. On the other hand, air conditioning is almost unheard of compared to the US outside retail. Even office buildings usually only have desk fans.

conaclos 4y ago

Two weeks ago, we talked about thermo-acoustic heat pumps on HN [1]. This could interest most of the readers of this thread. [1] https://news.ycombinator.com/item?id=34233719 https://news.ycombinator.com/item?id=34233719

dghughes 4y ago

I'd prefer a heat pump that uses ducts I hate the look of ductless heat pump that giant eyesore lump on the wall. But ducted are not as efficient compared to ductless due to the long runs of ducts and cold attics (even if ducts insulated). Plus my province won't give any rebates for ducted only ductless. Even better would be ground-source heat pump. But still I'd prefer ducts I think you'd have to with a ground source system.