Article Sharing: Cold Climate Heat Pump Challenge

DJDrew

Anyone hear of this "Cold Climate Heat Pump Challenge"? Looks pretty cool. The biggest issue with most heat pumps is the efficiency ratio at low outdoor temps.

https://www.pv-magazine.com/2022/11/03/air-source-heat-pump-for-harsh-cold-climates/

hot_rod

Hard to pull a lot of heat from -20°F air! Amazing it works at all. I suppose any COP above 1 is still beating electric resistance.

Some of the ccA2WHP controls keep the HP running and bring on a boiler or other backup source. Use the HP as long as it is more cost effective than the backup source.

Hot_water_fan

Very interesting - but Mitsubishi and others already have heat pumps that work to the negative Fahrenheit teens, so these gains are marginal.  I wonder about how useful this is - should be extremely helpful for the grid, but who cares about that when they’re buying one? Maybe the utilities will pay for it? Or would a propane furnace backup be cheaper? 

hot_rod

Hot_water_fan said:

Very interesting - but Mitsubishi and others already have heat pumps that work to the negative Fahrenheit teens, so these gains are marginal.  I wonder about how useful this is - should be extremely helpful for the grid, but who cares about that when they’re buying one? Maybe the utilities will pay for it? Or would a propane furnace backup be cheaper? 

I think the goal is to get efficiency up when under those severe operating conditions

we know 180F is possible , and sub zero operation. Now getting it all together, high temperature, low ambient, and highest COP

It will happen at some point, lots of R&D going into the challange.

fentonc

Here are the requirements they're trying to meet: https://www.energy.gov/sites/default/files/2022-02/bto-cchp-fact-sheet-021822.pdf

The main target seems to be 100% capacity and a COP of 2.1-2.4 at 5F using a refrigerant with a GWP of less than 750 (so R-32 is okay, R-410a is not). I bet Mitsubishi and some others might already meet this target, but from the DOE's perspective, the more the merrier. I think anything with that performance would have cheaper operating costs than natural gas here in ConEd territory.

Dave Carpentier

Wow, -15f (-26c) is starting to get near my design temp.
I could manage to live with strip heating when it's below that, not a huge amount of the season.
Alas, if it burns up the compressor just after the warranty period ends...
Still, good to see they're making targets like that.

RayWohlfarth

I found this study done by the government a few years ago. It showed substantially lower heating costs with gas than a heat pump. It was for cold climates. I found it interesting

https://nrel.gov/docs/fy15osti/63913.pdf

hot_rod

Air to air mini splits, or air to water units?

Hot_water_fan

Today's gas prices have ended that

RayWohlfarth

@hot_rod air to air
@Hot_water_fan Like I said it was a few years ago LOL