The radiator has flaps that close. Nothing more can be done.Or could it be in regards to heat load? For example, in the -5C scenario, does it try to warm up the coolant further to transfer more heat to cabin air if you switch from recirc to external? What about if you crack open the windows for a while?
Hmm. That's not good, I wonder if it might be possible to add a barrier between that part of the powertrain compartment and the rest of the vehicle.
Heck, it may simply be that you'll get significant improvement by doing what some diesel truck drivers do in extreme cold weather - block off the radiator to reduce airflow through the engine compartment. Just don't forget to remove it when it starts getting warmer!!!!
Maybe the heat load does something.
Problem is I have no clue - I cannot hear any change - when it is in recirc or fresh air mode. I tried manually switch it and either it is so quiet or... does not work
I did not try to crack a window, though.
Yes, I saw it a while ago.A forum member did a pretty good job of it.
And while it works, it just looks... bad.
I am beyond the "half ass solution" stage in my life.
When I do it - I do it once and good. Duct tape? Some pieces flying here and there? No, not really.
There is still a part of me that is thinking - is the whole ordeal worth it?
Let's look on it.
From my driving in winter, about 20-25% goes to heating.
Just for the math itself assume I did 120 miles on average 2.0 miles/kWh. Very cold period.
I used 60 kWh, 25% heat, 15% battery. That means: 36/15/9 kWh for driving/climate/battery respectively.
Theoretically it means I drive at 3.3 miles/kWh - about right: winter tires, snow...
Now, insulation would drop what? 10% of the total heat? I mean, how much is actually lost there? Heck, lets assume even 20% which is VERY generous in my opinion.
New numbers are like this: 36/12/9 kWh for the total of 57 kWh.
Now I can drive extra 6 miles and my 2.0 becomes 2.1 average. I guess it is pointless...
It will NOT resolve a heat delivery delay. It will not resolve overall heat loss due to parked car.
In order to warm up the 2 liters of water (glycol needs less energy, has lower specific heat or heat capacity if you will) you need theoretically 90 Wh of energy. That is from 10 C to 50 C
Based on my measurements it takes about 3 minutes, short of 1 mile ride at full power of 7.5 kW.
It means that all the pieces around need heat as well. Pump, tank, heater, pipes...
That gives a total of 375 Wh.
Each time you park or drive a short distance, all the 375 Wh is lost.
No insulation will help. I mean, insulation will slow it down... but after 8 hours at work - it makes no difference.
Make it 5 trips (days), 10 total of cycles - you just lost 3.75 kWh just there.
That is what makes this system inefficient.
PTC heater does not have this problem.