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In Northern Europe heat pumps are now pretty much standard for new homes. They reduce heating bills quite dramatically compared to other technology. In particul

In Northern Europe heat pumps are now pretty much standard for new homes. They reduce heating bills quite dramatically compared to other technology. In particular if combined with solar power. One big advantage is that they can also be run in reverse so you could cool the house in summer (although you might need a special heat pump to do this, especially to separate from the hot water). In areas where it gets very cool, one can also use connect the heat pump to the ground as heat sink which improves efficiency even more.

elric 5y ago
> One big advantage is that they can also be run in reverse I don't get why this is an advantage. That's just plain old air conditioning, which is genreally considered to be a wasteful, energy guzzling luxury in colder climates. The heat pump hype is a bit puzzling to me. Here's a TreeHugger article which puts it better than I can: https://www.treehugger.com/why-are-there-so-many-fist-pumps-for-heat-pumps-these-days-5191393 https://www.treehugger.com/why-are-there-so-many-fist-pumps-...
- jcynix 5y ago
  Good heat pumps aren't of the air conditioner type. Our heat pump uses two 60m deep drilled holes. Thus heat exchange happens in the ground, which is always more or less 10 degrees Celsuis. Heat exchange in the house happens through floor heating. So during a hit summer, the reverse capability just pumps the cold water through our floors (controlled for the dew point) and the warm floor water into the ground. That, combined with controlled ventilation over a physical heat exchanger, keeps the warmth out. Or, during cool seasons, the warmth in. Our heat pump uses about 1 Kwh electricity (from ecological resources like water or wind only) to generatev3 to 4 Kwh of heating. Without producing carbon dioxide. Airflow based heat pumps are less efficient, and more noisy outside, of course.
  - mprev 5y ago
    What sort of problems did you encounter drilling two 60m deep holes? How wide are they?
    - brtkdotse 5y ago
      Usually 100-150mm wide. You don't do it yourself, you get a company with a drilling rig to come out and do it. Costs around 5k€.
    - jcynix 5y ago
      We did have no problems as the ground below consists mostly of clay for at least 100 meters. Two times at 60m was a political limit 10 years ago, because at 100 meters "suddenly" mining rules applied. The tubes are about 100 mm in U-form, drilling mostly is offered in combination with the heat pump. And costs where payed of after about 7 years. Costs and problems depend on the ground's structure. When I talked with the guys of the drilling team, they told me that problems occur if they work in hill regions with cavernous spots in the ground. That's because the tubes need firm contact to the ground to transfer heat. Edit: here's an image of the drilling machine in operation: http://www.cynix.net/2008/img_1757.jpg http://www.cynix.net/2008/img_1757.jpg and the tubes are those black ones on the rolls in the front.
  - elric 5y ago
    > Good heat pumps aren't of the air conditioner type. Our heat pump uses two 60m deep drilled holes. Thus heat exchange happens in the ground, which is always more or less 10 degrees Celsuis. Good point. The source and destination of heat can be air, water, or "ground source". But it's still all just the same concept as A/C units. Pump heat to one place, using less energy than what it would take to heat it using resistance heating. There is nothing special about ground source heat pumps, except that they're a pain to install in densely populated areas. All types of heat pumps, unfortunately, often leak. Depending on the type of refrigerant they use, this can be a serious climate concern as well.
    - jcynix 5y ago
      There's no refrigerant here. Our heat pump uses plain water mixed with an anti-freezing agent. Just like the cooler in a car does. And there are control displays where you control all operating parameters. As for the "pump heat from here to there" ... while we are cooling we are warming the ground below. And as at our place, the ground's consistency keeps the warmth rather local, we reuse it later when we warm our water during the night. We do live in a densely populated area and about every fifth hoiuse built here during the last 10 years uses a ground-based heat pump. As for electricity use: each house has two hours of "blockage" where the pump is not allowed to run, so that the power lines aren't stressed. That's no problem at all, because all houses are highly insulated and thus buffer rather good.
      - bluGill 5y ago
        There is refrigerant there. It is contained inside the system, and only your water mix leaves, but there is still refrigerant inside and it can leak.
        jcynix 5y ago
        That's correct. I was comparing our system to existing systems which directly use a refrigerant sent into the ground loop. Our heat pump itself is a closed system just as a refrigerator, and works indirectly via the water cycle used outside.
  - brtkdotse 5y ago
    > Airflow based heat pumps are less efficient, and more noisy outside, of course. This is only true when the ambient temperature dips below the geothermal temperature which depending on your location should make you prefer one over the other.
    - jcynix 5y ago
      Germany. Where temperatures dip for some months below the geothermal temperature. Efficiency of air based pumps drops markedly when temperatures reach below 0 degrees Celsius. And last but not least: ground / water carries much more energy per volume unit than air does. So air based heat pumps would make more sense in Europe's south and less sense farther north.
      - brtkdotse 5y ago
        Modern water/air heat pumps have surprsingingly high efficiency down to -20C. We're running a 10 year old model that has no trouble heating our house down to -12, after which a direct electric helper element kicks in.
  - sidewndr46 5y ago
    Is English a second language for you? I ask not because I am trying to insult, but what you are describing is just called geothermal heat in North America. It can also work in reverse if the air temperature is higher than the ground temperature. Also, you have your units wrong. Electrical demand is measured in just kilowatts (kw). Actual usage is in kilowatts-hours (kwh) which is just an unusual way of saying joules.
    - scotty79 5y ago
      Units are fine. He just said he gets energy as heat in the amount 4 times higher than amount of electrical energy he uses to get it. It's fine to talk about it in terms of energy as it would be to talk about it in terms of power. And I'd argue that kWh is exactly the usual way of saying 3600000 joules. Also name "geothermal heat" for ground heat pumps might be a local US marketing term. In international English geothermal means rather what Iceland is mostly doing. Pumping water into very hot rocks deep below to extract heat. And it doesn't work in reverse because it would be additional work to pump heat into very hot rocks instead of dumping it into the air or into the cool ground 2 meters below the surface.
      - sidewndr46 5y ago
        I don't know anything about Iceland but I am using the definition from energy.gov https://www.energy.gov/energysaver/heat-and-cool/heat-pump-systems/geothermal-heat-pumps https://www.energy.gov/energysaver/heat-and-cool/heat-pump-s... Geothermal works with either vertical holes in the ground or a big loop spread out horizontally. Neither one is very deep nor does it involve hot rocks.
        scotty79 5y ago
        Ah, geothermal heat pumps is perfectly accurate. Geothermal heat on the other hand is a wider term https://en.m.wikipedia.org/wiki/Geothermal_heating https://en.m.wikipedia.org/wiki/Geothermal_heating of which geothermal heat pumps (ground source heat pumps) https://en.m.wikipedia.org/wiki/Ground_source_heat_pump https://en.m.wikipedia.org/wiki/Ground_source_heat_pump are just a subset.
- chiph 5y ago
  Yes, air-exchange heat pumps have been around forever. But they're usually of the all-the-way-on or all-the-way-off type in the US. Newer systems use variable refrigerant flow and variable fan speeds to save energy, so they run more proportionally to the heating/cooling load. They have a higher up front cost so production builders don't put them in, but custom home builders will. In cold climates you eventually hit an efficiency wall with the air-exchange units and need to use a ground-source heat pump, with glycol pipes being run deep in the ground to exchange heat. And/or also have a supplemental source of heat that only comes on during the very coldest periods (oil-fired furnace, natural gas, cast-iron stove, or even resistance heat). In hot climates you can increase the efficiency of a heat pump by adding water mist, making it a hybrid swamp cooler. Evaporating water will take out a bunch of heat energy. As was mentioned, insulation is key otherwise you're just spending money on heating or cooling the outdoors. Walls, door, and windows that don't have thermal bridges, controlled air exchange with the outdoors (ERV energy recovery ventilator units), and so on.
- bserge 5y ago
  Compressors (the biggest power usage in an A/C) have gotten more efficient, plus they remove the fans in favor of dumping heat straight into the ground. That's about it, it's still basically an A/C unit.
brtkdotse 5y ago
Another thing Northern Europe has going for it is that we generally go all-in on insulation. 300mm of insulation are norm in newly built house, meaning you can heat a whole house above the Arctic line with less than 5000 kWh a year. Insulation is _dirt cheap_ compared to lifetime heating costs AND it also keeps the house cool during the summer. Such a no-brainer.
- kpozin 5y ago
  Out of curiosity, what is the effect of this thick insulation on indoor CO₂ levels? Do these houses usually have ventilation systems that can compensate?
  - tomarr 5y ago
    They are designed for a number of air changes per hour/day which would be analogous I guess. I can't remember the number but a Google will tell you, it's different depending on the kind of environment (office/home etc)
  - brtkdotse 5y ago
    Usually heat exchanger ventilations. Fresh air comes in and exchanges heat with used air coming out, so you get fresh air but with the indoor temperature.
    - BizarroLand 5y ago
      HRV (Heat Recovery Ventilator) systems are really cool, too. They solve the ages old problem of bringing fresh air into a home without losing all of the temperature and humidity from the internal environment.
  - roel_v 5y ago
    Yes you need active ventilation systems, because the thermal efficiency is highly dependant on the house being airtight - to the point where efficiency scores are calculated by overpressuring the house (basically taping a huge fan into the front door with all other doors and windows shut) and measuring the pressure loss. When applying insulation, contractors have to meticulously use foam to seal everything up. It's a major part of the work when building a new house and just a few mistakes can seriously affect thermal performance.
paul_f 5y ago
Europe has milder winters than many parts of the world. A downside of a heat pump is the limitation on temperature range. A heat pump could never be used in Minnesota, people would freeze.
- throw0101a 5y ago
  > A heat pump could never be used in Minnesota, people would freeze. Heat pumps work in Alaska: * https://www.nrel.gov/news/features/2021/even-in-frigid-temperatures-air-source-heat-pumps-keep-homes-warm-from-alaska-coast-to-us-mass-market.html https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...
  - bluGill 5y ago
    The more inhabited parts of Alaska are milder climates than MN, despite being northern they have an ocean to moderate the temperatures. Ground source heat pumps work fine in both MN and the most remote parts of Alaska - but at a much higher cost to install.
- JoeAltmaier 5y ago
  That would be an air heat pump. Water or earth-exchange heat pumps can work nearly anywhere. This article explains it well: https://www.nordicghp.com/2017/01/heat-pump-effective-temperature-range/ https://www.nordicghp.com/2017/01/heat-pump-effective-temper...
- LysPJ 5y ago
  Heat pumps are very widely used here in Norway. I wouldn't class our winters as "mild" :)
- acdha 5y ago
  Ground source heat pumps work anywhere. Also, it's common to have a heat pump paired with resistance heating for when you're pushing the bottom of the range where the heat pump is useful (somewhere between -10 and 20℉ depending on the hardware). That has similar issues with peak load to AC in the summer but most people do not live in places which are consistently so cold that you don't have a significant amount of time where the heat pump efficiency savings are substantial. As a matter of public policy, encouraging systems which work for 90% of the population is an easy call — especially because that can pair with code changes and subsidies which work anywhere (insulation, install of ground cooling loops, efficiency improvements, etc.).
matheusmoreira 5y ago
Is it possible to hook up computer heat sinks to these things? I figure it'd be better to pump the heat outside my home instead of dissipating it into my air conditioned rooms...
- bserge 5y ago
  It would basically be a phase change cooler like the one used in a fridge. Very efficient, but quite big and unwieldy.
- landemva 5y ago
  I want that for my fridge. Move the compressor and radiator somewhere else than the kitchen.
  - matheusmoreira 5y ago
    That'd be cool. Those things make a lot of noise. Would be nice if the refrigeration hardware itself was located as far as possible from the living areas. What if homes had some kind of centralized modular heat exchanging infrastructure? That way we could move heat from hot things that need to be cold to cold things that need to be hot. Move heat from my computers to a water heater or something. Gotta use all that excess heat for something, right?

elric 5y ago

> One big advantage is that they can also be run in reverse I don't get why this is an advantage. That's just plain old air conditioning, which is genreally considered to be a wasteful, energy guzzling luxury in colder climates. The heat pump hype is a bit puzzling to me. Here's a TreeHugger article which puts it better than I can: https://www.treehugger.com/why-are-there-so-many-fist-pumps-for-heat-pumps-these-days-5191393 https://www.treehugger.com/why-are-there-so-many-fist-pumps-...

jcynix 5y ago
Good heat pumps aren't of the air conditioner type. Our heat pump uses two 60m deep drilled holes. Thus heat exchange happens in the ground, which is always more or less 10 degrees Celsuis. Heat exchange in the house happens through floor heating. So during a hit summer, the reverse capability just pumps the cold water through our floors (controlled for the dew point) and the warm floor water into the ground. That, combined with controlled ventilation over a physical heat exchanger, keeps the warmth out. Or, during cool seasons, the warmth in. Our heat pump uses about 1 Kwh electricity (from ecological resources like water or wind only) to generatev3 to 4 Kwh of heating. Without producing carbon dioxide. Airflow based heat pumps are less efficient, and more noisy outside, of course.
- mprev 5y ago
  What sort of problems did you encounter drilling two 60m deep holes? How wide are they?
  - brtkdotse 5y ago
    Usually 100-150mm wide. You don't do it yourself, you get a company with a drilling rig to come out and do it. Costs around 5k€.
  - jcynix 5y ago
    We did have no problems as the ground below consists mostly of clay for at least 100 meters. Two times at 60m was a political limit 10 years ago, because at 100 meters "suddenly" mining rules applied. The tubes are about 100 mm in U-form, drilling mostly is offered in combination with the heat pump. And costs where payed of after about 7 years. Costs and problems depend on the ground's structure. When I talked with the guys of the drilling team, they told me that problems occur if they work in hill regions with cavernous spots in the ground. That's because the tubes need firm contact to the ground to transfer heat. Edit: here's an image of the drilling machine in operation: http://www.cynix.net/2008/img_1757.jpg http://www.cynix.net/2008/img_1757.jpg and the tubes are those black ones on the rolls in the front.
- elric 5y ago
  > Good heat pumps aren't of the air conditioner type. Our heat pump uses two 60m deep drilled holes. Thus heat exchange happens in the ground, which is always more or less 10 degrees Celsuis. Good point. The source and destination of heat can be air, water, or "ground source". But it's still all just the same concept as A/C units. Pump heat to one place, using less energy than what it would take to heat it using resistance heating. There is nothing special about ground source heat pumps, except that they're a pain to install in densely populated areas. All types of heat pumps, unfortunately, often leak. Depending on the type of refrigerant they use, this can be a serious climate concern as well.
  - jcynix 5y ago
    There's no refrigerant here. Our heat pump uses plain water mixed with an anti-freezing agent. Just like the cooler in a car does. And there are control displays where you control all operating parameters. As for the "pump heat from here to there" ... while we are cooling we are warming the ground below. And as at our place, the ground's consistency keeps the warmth rather local, we reuse it later when we warm our water during the night. We do live in a densely populated area and about every fifth hoiuse built here during the last 10 years uses a ground-based heat pump. As for electricity use: each house has two hours of "blockage" where the pump is not allowed to run, so that the power lines aren't stressed. That's no problem at all, because all houses are highly insulated and thus buffer rather good.
    - bluGill 5y ago
      There is refrigerant there. It is contained inside the system, and only your water mix leaves, but there is still refrigerant inside and it can leak.
      - jcynix 5y ago
        That's correct. I was comparing our system to existing systems which directly use a refrigerant sent into the ground loop. Our heat pump itself is a closed system just as a refrigerator, and works indirectly via the water cycle used outside.
- brtkdotse 5y ago
  > Airflow based heat pumps are less efficient, and more noisy outside, of course. This is only true when the ambient temperature dips below the geothermal temperature which depending on your location should make you prefer one over the other.
  - jcynix 5y ago
    Germany. Where temperatures dip for some months below the geothermal temperature. Efficiency of air based pumps drops markedly when temperatures reach below 0 degrees Celsius. And last but not least: ground / water carries much more energy per volume unit than air does. So air based heat pumps would make more sense in Europe's south and less sense farther north.
    - brtkdotse 5y ago
      Modern water/air heat pumps have surprsingingly high efficiency down to -20C. We're running a 10 year old model that has no trouble heating our house down to -12, after which a direct electric helper element kicks in.
- sidewndr46 5y ago
  Is English a second language for you? I ask not because I am trying to insult, but what you are describing is just called geothermal heat in North America. It can also work in reverse if the air temperature is higher than the ground temperature. Also, you have your units wrong. Electrical demand is measured in just kilowatts (kw). Actual usage is in kilowatts-hours (kwh) which is just an unusual way of saying joules.
  - scotty79 5y ago
    Units are fine. He just said he gets energy as heat in the amount 4 times higher than amount of electrical energy he uses to get it. It's fine to talk about it in terms of energy as it would be to talk about it in terms of power. And I'd argue that kWh is exactly the usual way of saying 3600000 joules. Also name "geothermal heat" for ground heat pumps might be a local US marketing term. In international English geothermal means rather what Iceland is mostly doing. Pumping water into very hot rocks deep below to extract heat. And it doesn't work in reverse because it would be additional work to pump heat into very hot rocks instead of dumping it into the air or into the cool ground 2 meters below the surface.
    - sidewndr46 5y ago
      I don't know anything about Iceland but I am using the definition from energy.gov https://www.energy.gov/energysaver/heat-and-cool/heat-pump-systems/geothermal-heat-pumps https://www.energy.gov/energysaver/heat-and-cool/heat-pump-s... Geothermal works with either vertical holes in the ground or a big loop spread out horizontally. Neither one is very deep nor does it involve hot rocks.
      - scotty79 5y ago
        Ah, geothermal heat pumps is perfectly accurate. Geothermal heat on the other hand is a wider term https://en.m.wikipedia.org/wiki/Geothermal_heating https://en.m.wikipedia.org/wiki/Geothermal_heating of which geothermal heat pumps (ground source heat pumps) https://en.m.wikipedia.org/wiki/Ground_source_heat_pump https://en.m.wikipedia.org/wiki/Ground_source_heat_pump are just a subset.
chiph 5y ago
Yes, air-exchange heat pumps have been around forever. But they're usually of the all-the-way-on or all-the-way-off type in the US. Newer systems use variable refrigerant flow and variable fan speeds to save energy, so they run more proportionally to the heating/cooling load. They have a higher up front cost so production builders don't put them in, but custom home builders will. In cold climates you eventually hit an efficiency wall with the air-exchange units and need to use a ground-source heat pump, with glycol pipes being run deep in the ground to exchange heat. And/or also have a supplemental source of heat that only comes on during the very coldest periods (oil-fired furnace, natural gas, cast-iron stove, or even resistance heat). In hot climates you can increase the efficiency of a heat pump by adding water mist, making it a hybrid swamp cooler. Evaporating water will take out a bunch of heat energy. As was mentioned, insulation is key otherwise you're just spending money on heating or cooling the outdoors. Walls, door, and windows that don't have thermal bridges, controlled air exchange with the outdoors (ERV energy recovery ventilator units), and so on.
bserge 5y ago
Compressors (the biggest power usage in an A/C) have gotten more efficient, plus they remove the fans in favor of dumping heat straight into the ground. That's about it, it's still basically an A/C unit.

brtkdotse 5y ago

Another thing Northern Europe has going for it is that we generally go all-in on insulation. 300mm of insulation are norm in newly built house, meaning you can heat a whole house above the Arctic line with less than 5000 kWh a year. Insulation is _dirt cheap_ compared to lifetime heating costs AND it also keeps the house cool during the summer. Such a no-brainer.

kpozin 5y ago
Out of curiosity, what is the effect of this thick insulation on indoor CO₂ levels? Do these houses usually have ventilation systems that can compensate?
- tomarr 5y ago
  They are designed for a number of air changes per hour/day which would be analogous I guess. I can't remember the number but a Google will tell you, it's different depending on the kind of environment (office/home etc)
- brtkdotse 5y ago
  Usually heat exchanger ventilations. Fresh air comes in and exchanges heat with used air coming out, so you get fresh air but with the indoor temperature.
  - BizarroLand 5y ago
    HRV (Heat Recovery Ventilator) systems are really cool, too. They solve the ages old problem of bringing fresh air into a home without losing all of the temperature and humidity from the internal environment.
- roel_v 5y ago
  Yes you need active ventilation systems, because the thermal efficiency is highly dependant on the house being airtight - to the point where efficiency scores are calculated by overpressuring the house (basically taping a huge fan into the front door with all other doors and windows shut) and measuring the pressure loss. When applying insulation, contractors have to meticulously use foam to seal everything up. It's a major part of the work when building a new house and just a few mistakes can seriously affect thermal performance.

paul_f 5y ago

Europe has milder winters than many parts of the world. A downside of a heat pump is the limitation on temperature range. A heat pump could never be used in Minnesota, people would freeze.

throw0101a 5y ago
> A heat pump could never be used in Minnesota, people would freeze. Heat pumps work in Alaska: * https://www.nrel.gov/news/features/2021/even-in-frigid-temperatures-air-source-heat-pumps-keep-homes-warm-from-alaska-coast-to-us-mass-market.html https://www.nrel.gov/news/features/2021/even-in-frigid-tempe...
- bluGill 5y ago
  The more inhabited parts of Alaska are milder climates than MN, despite being northern they have an ocean to moderate the temperatures. Ground source heat pumps work fine in both MN and the most remote parts of Alaska - but at a much higher cost to install.
JoeAltmaier 5y ago
That would be an air heat pump. Water or earth-exchange heat pumps can work nearly anywhere. This article explains it well: https://www.nordicghp.com/2017/01/heat-pump-effective-temperature-range/ https://www.nordicghp.com/2017/01/heat-pump-effective-temper...
LysPJ 5y ago
Heat pumps are very widely used here in Norway. I wouldn't class our winters as "mild" :)
acdha 5y ago
Ground source heat pumps work anywhere. Also, it's common to have a heat pump paired with resistance heating for when you're pushing the bottom of the range where the heat pump is useful (somewhere between -10 and 20℉ depending on the hardware). That has similar issues with peak load to AC in the summer but most people do not live in places which are consistently so cold that you don't have a significant amount of time where the heat pump efficiency savings are substantial. As a matter of public policy, encouraging systems which work for 90% of the population is an easy call — especially because that can pair with code changes and subsidies which work anywhere (insulation, install of ground cooling loops, efficiency improvements, etc.).

matheusmoreira 5y ago

Is it possible to hook up computer heat sinks to these things? I figure it'd be better to pump the heat outside my home instead of dissipating it into my air conditioned rooms...

bserge 5y ago
It would basically be a phase change cooler like the one used in a fridge. Very efficient, but quite big and unwieldy.
landemva 5y ago
I want that for my fridge. Move the compressor and radiator somewhere else than the kitchen.
- matheusmoreira 5y ago
  That'd be cool. Those things make a lot of noise. Would be nice if the refrigeration hardware itself was located as far as possible from the living areas. What if homes had some kind of centralized modular heat exchanging infrastructure? That way we could move heat from hot things that need to be cold to cold things that need to be hot. Move heat from my computers to a water heater or something. Gotta use all that excess heat for something, right?