6 ms·

What's the efficiency compared to traditional compressors? I imagine there are a lot of opportunity for thermal energy to leak on the sides... Edit: 20-30%, up

What's the efficiency compared to traditional compressors? I imagine there are a lot of opportunity for thermal energy to leak on the sides... Edit: 20-30%, up to 40%, according to wikipedia.

idiotsecant 4y ago
I am building right now and my state (washington) recently decided no more natural gas heat, heat pumps only. That's great for the warmer side of the state but most heat pumps don't work great when it's 10 below - they approach zero efficiency the colder it gets. Blueheart seems to claim they can output 60C on the hot end when the cold end is -20C. In addition, EQUIUM seems to claim a 30 year lifetime on their acoustic chamber because it has essentially no moving parts, it's just a pressure vessel. If both of these things are true it could eventually be an advantage over heat pumps for people in cold conditions or people who are sensitive to maintenance costs once the technology is mature. Or all the (very vague) specs could be marketing junk and it's vaporware. Neat either way.
- moloch-hai 4y ago
  Modern heat pumps work down to pretty low temperature, but the amount of heat you can get out at a low temperature may not be enough to stay warm with. As outside temperature goes down, you need an increasing amount of heat input. At a particular point (which depends on temperature and wind speed) capacity is exceeded, and inside temperature falls. Then you need an alternative source of heat. Typically this is a propane furnace, but may be a resistive heater. The heat pump saves on your bill except during cold snaps, and then cost spikes.
  - thehappypm 4y ago
    Typically the backup is resistive, in a ducted system, it’s basically a big heater coil in the heat exchanger area. One of my two properties has one. It has never been used though, AFAIK, because it hasn’t gotten cold enough yet (and frankly, in Eastern Massachusetts, it is not very common anyway).
    - lsllc 4y ago
      If you have propane/nat gas for hot water, you can use that as the backup heat -- just need a combi-boiler with a single zone through a hydronic loop in the air handler stack.
      - thehappypm 4y ago
        I do not, no gas line to the house. I had an oil furnace which I replaced hydronic with heat pump + resistive backup. Saving about $300/month this winter
  - pxmpxm 4y ago
    This - we've got a brand new Daikin heat pump at 10F/-12C outside temp, it took full 24 hours to bring our place from 50F/10C to 72F/22C. A regular nat gas furnace would knock it out in about and hour and half, and at fraction of the cost. Incidentally we're in the process of installing a nat gas tankless combi heater to address this issue - you can get a forced air set up with those.
- tzs 4y ago
  > That's great for the warmer side of the state but most heat pumps don't work great when it's 10 below - they approach zero efficiency the colder it gets. Mitsubishi heat pumps with the "Hyper-heating inverter" technology are above 100% efficiency down to -15℉ (-26℃). They are 200% at 0℉ (-18℃), 300% at 32℉ (0℃). Their capacity drops from 100% at 23℉ (-5℃) to 76% at -13℉ (-25℃). Fujitsu has similar technology, as do a few others now.
  - bfeynman 4y ago
    After really looking into this for my own home, I think there is some marketing BS involved. "Efficiency" is an inflated metric, it gets to a certain temperature a heat pump is going to be the equivalent of electric heat, purely expending energy to heat things up. Additionally, they have to be constantly on and cycling so they don't break the colder it gets. A gas furnace can be fired up almost in any temperature and is still very efficient. Not to mention that efficiency doesn't really tie to how exorbitantly expensive it is to run heat pumps, you're looking at +$500-800 month in extra electricity costs in some places.
    - hijinks 4y ago
      I had a home in the CO mountains at 10k feet above sea level. I was looking at heat pumps since the house was electric baseboard and running a gas line was gonna cost $18k just for the line to the home. I decided on heat pumps and was lucky enough to find a reseller of Mitsubishi who mentioned his contacts there were looking for a cold climate home in elevation that wanted heat pumps to prove their tech. Long story short, I put in heat pumps at a fraction of the cost of what it would normally cost. Now the benefit of the mountains as opposed to Denver is it rarely gets below 0 even if Denver is -15 the mountain low might be -5ish. Yes efficiency goes down the colder it gets but when I owned the home I never had to supplement the heat pumps to keep the house warm. It would pull 120F heat when it was -5 out. Again when its -5 natural gas is a lot more efficient but the idea is its not -5 all year. The first year I had them my electric bill averaged $650ish to $310. Also I got AC in the summer as a bonus.
      - 4y ago
- closedl00p 4y ago
  Anecdotally, a few people I know who moved to New England (where it can get down to -20F at night, though rarely) have installed heat pumps and been happy with the performance through the past few winters, though I don't know which models they bought (one mentioned the Mitsubishi H2i). I believe all of them also have a woodstove for backup heat and general coziness, but no separate fossil fuel backup.
  - stephencanon 4y ago
    Yeah, we live in northern New England; (air source) heat pump + wood stove is getting to be a very popular combination around here.
    - bfeynman 4y ago
      do you live in a well insulated (net-zero or passive home)?
- yxhuvud 4y ago
  The solution to that is to not use an air based heat pump but to drill down into the bedrock, well past the freezing depths and circulate water down the hole and take warmth from there. This is quite a bit heavier on the investment side but a lot more efficient during cold weather.
- jaclaz 4y ago
  I would be very cautious with declared lifetime of non-existing things, all Equium (and seemingly the other player Blueheart, that state a much more conservative 15 years lifetime) have right now are laboratory prototypes. If you check the Blueheart "About" site here: https://www.blueheartenergy.com/ https://www.blueheartenergy.com/ they have nice pictures of the various prototypes and of the (supposedly final) product, you can appreciate at a glance how different they look, and it wouldn't be the first time that expected lifetime (estimated on prototypes) results vary for the industrialized product.
zaarn 4y ago
According to a different article the COP of this heat pump is between 3-4. However, Thermoaccoustic Heat Pumps have some advantages that you can also find in their press release; because there is no refridgerant, only the air medium which is Helium in this case, you can operate them down at much much lower temperatures without loosing much COP, same in reverse (they claim -15C to 50C). And because there is few moving parts (only the acoustic coupler) they can have an immensely better lifetime than a compressor that needs oiling and maintenance (Equium claims 30 years service life). They aim for fairly small heat pumps from the looks of it, so this might be something targeted at people renting flats. Something to replace the gas burner for most of the winter.

What's the efficiency compared to traditional compressors? I imagine there are a lot of opportunity for thermal energy to leak on the sides... Edit: 20-30%, up to 40%, according to wikipedia.

idiotsecant 4y ago

I am building right now and my state (washington) recently decided no more natural gas heat, heat pumps only. That's great for the warmer side of the state but most heat pumps don't work great when it's 10 below - they approach zero efficiency the colder it gets. Blueheart seems to claim they can output 60C on the hot end when the cold end is -20C. In addition, EQUIUM seems to claim a 30 year lifetime on their acoustic chamber because it has essentially no moving parts, it's just a pressure vessel. If both of these things are true it could eventually be an advantage over heat pumps for people in cold conditions or people who are sensitive to maintenance costs once the technology is mature. Or all the (very vague) specs could be marketing junk and it's vaporware. Neat either way.

moloch-hai 4y ago
Modern heat pumps work down to pretty low temperature, but the amount of heat you can get out at a low temperature may not be enough to stay warm with. As outside temperature goes down, you need an increasing amount of heat input. At a particular point (which depends on temperature and wind speed) capacity is exceeded, and inside temperature falls. Then you need an alternative source of heat. Typically this is a propane furnace, but may be a resistive heater. The heat pump saves on your bill except during cold snaps, and then cost spikes.
- thehappypm 4y ago
  Typically the backup is resistive, in a ducted system, it’s basically a big heater coil in the heat exchanger area. One of my two properties has one. It has never been used though, AFAIK, because it hasn’t gotten cold enough yet (and frankly, in Eastern Massachusetts, it is not very common anyway).
  - lsllc 4y ago
    If you have propane/nat gas for hot water, you can use that as the backup heat -- just need a combi-boiler with a single zone through a hydronic loop in the air handler stack.
    - thehappypm 4y ago
      I do not, no gas line to the house. I had an oil furnace which I replaced hydronic with heat pump + resistive backup. Saving about $300/month this winter
- pxmpxm 4y ago
  This - we've got a brand new Daikin heat pump at 10F/-12C outside temp, it took full 24 hours to bring our place from 50F/10C to 72F/22C. A regular nat gas furnace would knock it out in about and hour and half, and at fraction of the cost. Incidentally we're in the process of installing a nat gas tankless combi heater to address this issue - you can get a forced air set up with those.
tzs 4y ago
> That's great for the warmer side of the state but most heat pumps don't work great when it's 10 below - they approach zero efficiency the colder it gets. Mitsubishi heat pumps with the "Hyper-heating inverter" technology are above 100% efficiency down to -15℉ (-26℃). They are 200% at 0℉ (-18℃), 300% at 32℉ (0℃). Their capacity drops from 100% at 23℉ (-5℃) to 76% at -13℉ (-25℃). Fujitsu has similar technology, as do a few others now.
- bfeynman 4y ago
  After really looking into this for my own home, I think there is some marketing BS involved. "Efficiency" is an inflated metric, it gets to a certain temperature a heat pump is going to be the equivalent of electric heat, purely expending energy to heat things up. Additionally, they have to be constantly on and cycling so they don't break the colder it gets. A gas furnace can be fired up almost in any temperature and is still very efficient. Not to mention that efficiency doesn't really tie to how exorbitantly expensive it is to run heat pumps, you're looking at +$500-800 month in extra electricity costs in some places.
  - hijinks 4y ago
    I had a home in the CO mountains at 10k feet above sea level. I was looking at heat pumps since the house was electric baseboard and running a gas line was gonna cost $18k just for the line to the home. I decided on heat pumps and was lucky enough to find a reseller of Mitsubishi who mentioned his contacts there were looking for a cold climate home in elevation that wanted heat pumps to prove their tech. Long story short, I put in heat pumps at a fraction of the cost of what it would normally cost. Now the benefit of the mountains as opposed to Denver is it rarely gets below 0 even if Denver is -15 the mountain low might be -5ish. Yes efficiency goes down the colder it gets but when I owned the home I never had to supplement the heat pumps to keep the house warm. It would pull 120F heat when it was -5 out. Again when its -5 natural gas is a lot more efficient but the idea is its not -5 all year. The first year I had them my electric bill averaged $650ish to $310. Also I got AC in the summer as a bonus.
    - 4y ago
closedl00p 4y ago
Anecdotally, a few people I know who moved to New England (where it can get down to -20F at night, though rarely) have installed heat pumps and been happy with the performance through the past few winters, though I don't know which models they bought (one mentioned the Mitsubishi H2i). I believe all of them also have a woodstove for backup heat and general coziness, but no separate fossil fuel backup.
- stephencanon 4y ago
  Yeah, we live in northern New England; (air source) heat pump + wood stove is getting to be a very popular combination around here.
  - bfeynman 4y ago
    do you live in a well insulated (net-zero or passive home)?
yxhuvud 4y ago
The solution to that is to not use an air based heat pump but to drill down into the bedrock, well past the freezing depths and circulate water down the hole and take warmth from there. This is quite a bit heavier on the investment side but a lot more efficient during cold weather.
jaclaz 4y ago
I would be very cautious with declared lifetime of non-existing things, all Equium (and seemingly the other player Blueheart, that state a much more conservative 15 years lifetime) have right now are laboratory prototypes. If you check the Blueheart "About" site here: https://www.blueheartenergy.com/ https://www.blueheartenergy.com/ they have nice pictures of the various prototypes and of the (supposedly final) product, you can appreciate at a glance how different they look, and it wouldn't be the first time that expected lifetime (estimated on prototypes) results vary for the industrialized product.

zaarn 4y ago

According to a different article the COP of this heat pump is between 3-4. However, Thermoaccoustic Heat Pumps have some advantages that you can also find in their press release; because there is no refridgerant, only the air medium which is Helium in this case, you can operate them down at much much lower temperatures without loosing much COP, same in reverse (they claim -15C to 50C). And because there is few moving parts (only the acoustic coupler) they can have an immensely better lifetime than a compressor that needs oiling and maintenance (Equium claims 30 years service life). They aim for fairly small heat pumps from the looks of it, so this might be something targeted at people renting flats. Something to replace the gas burner for most of the winter.