4 ms·

This doesn’t sound any better than the efficiency of Mitsubishi/Trane “hyper heat” heat pumps, which are already on the market.

joenathanone 4y ago
Domestic is the key here.
tzs 4y ago
It depends on what they mean by this: > The prototype delivers 100% heating at 5°F at double the efficiency, and 70% to 80% heating at -5°F and -10°F. DOE’s Oak Ridge National Laboratory validated the performance and efficiency of Lennox’s prototype. Usually when people talk about efficiency of heat pumps they are comparing to electrical resistance heating (which is 100% efficient). If that's what they mean then they are saying 200% efficient at 5℉, which is not as good as Mitsubishi, which is better than 200% at 0℉. But in the first paragraph they say: > The U.S. Department of Energy (DOE) today announced that American heat pump manufacturer Lennox International became the first partner in the U.S. Department of Energy’s (DOE’s) Residential Cold Climate Heat Pump Technology Challenge to develop a next-generation electric heat pump that can more effectively heat homes in northern climates relative to today’s models. It could be that they are stating efficiency compared to current heat pumps, not compared to resistance heating, in which case they would be claiming quite a bit higher efficiency than Mitsubishi, which would certainly justify calling it a breakthrough. Another possibility is that what they could be claiming as the breakthrough is the 100% heating at 5℉ part. The Mitsubishi cold weather heat pumps start losing capacity below 23℉, falling from 100% at 23℉ to 76% at -13℉. I don't think that would be as big a breakthrough as double the efficiency of current heat pumps, because it wouldn't make it so heat pumps are feasible in climates too cold for Mitsubishi. But it would make it so that in places you can use a heat pump you might not need as big of a heat pump with the new technology as you would need with a Mitsubishi. That could lower up front cost making converting from something else to a heat pump more feasible for many.
adrianmonk 4y ago
Mitsubishi's products seem to be mini-split systems[1]. --> EDIT: Or maybe not... they seem to offer forced-air too. <-- The DOE challenge is for ducted systems. Their site[2] says: > The Challenge is currently focused on residential, centrally ducted, electric-only HPs. The DOE challenge also has other requirements[3] that I don't know if the Mitsubishi systems satisfy. It requires certain levels of efficiency and "grid interactivity" (meaning Energy Star "demand response"[4] where your utility can temporarily tweak your thermostat settings). --- [1] https://www.mitsubishicomfort.com/residential/new-products https://www.mitsubishicomfort.com/residential/new-products [2] https://www.energy.gov/eere/buildings/cchp-technology-challenge-specifications https://www.energy.gov/eere/buildings/cchp-technology-challe... [3] https://www.energy.gov/sites/default/files/2021-10/bto-cchp-tech-challenge-spec-102521.pdf https://www.energy.gov/sites/default/files/2021-10/bto-cchp-... [4] https://www.energystar.gov/sites/default/files/ENERGY%20STAR%20Version%206.0%20Central%20Air%20Conditioner%20and%20Heat%20Pump%20Final%20Specification%20and%20Partner%20Commitments.pdf https://www.energystar.gov/sites/default/files/ENERGY%20STAR...
- R0b0t1 4y ago
  Kind of a shame, ducted heating has a lot of issues, but is the best for retrofit I guess.
- oneplane 4y ago
  I wonder why ducted systems were part of the requirements, is it because it's just aimed at the USA and then mostly at adoptability for existing systems (which seems to be ducted mostly)? I only have anecdotal experience and no numbers to back that up, but it's the only reason I can come up with that would put such a restriction in place. I'd say rip the ducts out and just use split systems but I imagine other people have thought about that and figured it's not the best way to go. (or at last not in the US)
  - pkulak 4y ago
    Yes, because nearly every house in cold climates is ducted, and we’re trying to get people off oil heating quickly, easily, and cheaply. Popping a new heat exchanger in an existing furnace is stupid simple compared to running coolant lines to new, wall-mounted exchangers all over the house.

joenathanone 4y ago

Domestic is the key here.

tzs 4y ago

It depends on what they mean by this: > The prototype delivers 100% heating at 5°F at double the efficiency, and 70% to 80% heating at -5°F and -10°F. DOE’s Oak Ridge National Laboratory validated the performance and efficiency of Lennox’s prototype. Usually when people talk about efficiency of heat pumps they are comparing to electrical resistance heating (which is 100% efficient). If that's what they mean then they are saying 200% efficient at 5℉, which is not as good as Mitsubishi, which is better than 200% at 0℉. But in the first paragraph they say: > The U.S. Department of Energy (DOE) today announced that American heat pump manufacturer Lennox International became the first partner in the U.S. Department of Energy’s (DOE’s) Residential Cold Climate Heat Pump Technology Challenge to develop a next-generation electric heat pump that can more effectively heat homes in northern climates relative to today’s models. It could be that they are stating efficiency compared to current heat pumps, not compared to resistance heating, in which case they would be claiming quite a bit higher efficiency than Mitsubishi, which would certainly justify calling it a breakthrough. Another possibility is that what they could be claiming as the breakthrough is the 100% heating at 5℉ part. The Mitsubishi cold weather heat pumps start losing capacity below 23℉, falling from 100% at 23℉ to 76% at -13℉. I don't think that would be as big a breakthrough as double the efficiency of current heat pumps, because it wouldn't make it so heat pumps are feasible in climates too cold for Mitsubishi. But it would make it so that in places you can use a heat pump you might not need as big of a heat pump with the new technology as you would need with a Mitsubishi. That could lower up front cost making converting from something else to a heat pump more feasible for many.

adrianmonk 4y ago

Mitsubishi's products seem to be mini-split systems[1]. --> EDIT: Or maybe not... they seem to offer forced-air too. <-- The DOE challenge is for ducted systems. Their site[2] says: > The Challenge is currently focused on residential, centrally ducted, electric-only HPs. The DOE challenge also has other requirements[3] that I don't know if the Mitsubishi systems satisfy. It requires certain levels of efficiency and "grid interactivity" (meaning Energy Star "demand response"[4] where your utility can temporarily tweak your thermostat settings). --- [1] https://www.mitsubishicomfort.com/residential/new-products https://www.mitsubishicomfort.com/residential/new-products [2] https://www.energy.gov/eere/buildings/cchp-technology-challenge-specifications https://www.energy.gov/eere/buildings/cchp-technology-challe... [3] https://www.energy.gov/sites/default/files/2021-10/bto-cchp-tech-challenge-spec-102521.pdf https://www.energy.gov/sites/default/files/2021-10/bto-cchp-... [4] https://www.energystar.gov/sites/default/files/ENERGY%20STAR%20Version%206.0%20Central%20Air%20Conditioner%20and%20Heat%20Pump%20Final%20Specification%20and%20Partner%20Commitments.pdf https://www.energystar.gov/sites/default/files/ENERGY%20STAR...

R0b0t1 4y ago
Kind of a shame, ducted heating has a lot of issues, but is the best for retrofit I guess.
oneplane 4y ago
I wonder why ducted systems were part of the requirements, is it because it's just aimed at the USA and then mostly at adoptability for existing systems (which seems to be ducted mostly)? I only have anecdotal experience and no numbers to back that up, but it's the only reason I can come up with that would put such a restriction in place. I'd say rip the ducts out and just use split systems but I imagine other people have thought about that and figured it's not the best way to go. (or at last not in the US)
- pkulak 4y ago
  Yes, because nearly every house in cold climates is ducted, and we’re trying to get people off oil heating quickly, easily, and cheaply. Popping a new heat exchanger in an existing furnace is stupid simple compared to running coolant lines to new, wall-mounted exchangers all over the house.