[jpm8766]

Also would point out that -4 C is about 25 F, which is not all that cold--at least for Colorado. It's not at all uncommon to get into the single digits F here, and well below zero in the mountains. Pretty much every morning for most of the winter it is below freezing.

I'm cautiously optimistic my future EV (several still on order, including ID.4, now for the past 8 months) will be able to meet my expectations in this type of weather. We haven't had a particularly cold northeast winter in a while, but we already have had a stretch of <25F weather for the past few days. Late January into February usually brings a few week-long stretches of <0F. I'd love to have more sub-zero F (-20C and below) temperature data to put my mind at ease that this car won't be a mistake.

 

[jpm8766]

COP of 2 at -20C is quite acceptable.

COP of 1 at ultra cold temperatures is perfectly acceptable to me as well, but at those temperatures, a completely frozen evaporator would stop the heat transfer entirely, no? I guess you're saying that R744 wouldn't suffer those consequences because it is CO2 based and a properly balanced system should be able to provide a larger efficient operating range without potentially freezing.

What I think I am getting out of this is the following lesson: "You might be able to look at performance of vehicles without heat pump in cold weather to get an idea of what range loss at extremely low temperatures and a heat pump could look like."

I'm really looking forward to the conclusion of Bjorn's ID.Buzz test in the arctic to see some more numbers that are easier to digest than thermodynamic intuition.