2013 heat pump data

I have some preliminary data for the 2013 heat pump with some winter temperatures. So far it is pretty impressive, but with the weather getting warmer most of the serious winter data will need to wait. So far all data has been with Eco mode since that seems to produce heat perfectly well with the heat pump. Heat is nearly instantaneous when started.

All data is with the climate control set to heat, auto, 68F. No pre-warming.

I will add data as I collect it.


28F heater used 3kW to start and then dropped to 1.5kW after a few minutes then dropped to ~ 1kW for the rest of my 30 minute commute

32F heater used 2.5kW to start and then dropped to 1.5kW after a few minutes then dropped to ~ 0.75kW for the rest of my 30 minute commute

40F heater used 1.5kW to start and then dropped to 1kW after a few minutes then dropped to ~ 0.5kW for the rest of my 30 minute commute

48F heater used 1.5kW to start and then dropped to 0.5kW after a few minutes then toggled between 0 and ~0.5kW for the rest of my 30 minute commute

bradbissell said:

I have some preliminary data for the 2013 heat pump with some winter temperatures. So far it is pretty impressive, but with the weather getting warmer most of the serious winter data will need to wait. So far all data has been with Eco mode since that seems to produce heat perfectly well with the heat pump. Heat is nearly instantaneous when started.

All data is with the climate control set to heat, auto, 68F. No pre-warming.

I will add data as I collect it.


28F heater used 3kW to start and then dropped to 1.5kW after a few minutes then dropped to ~ 1kW for the rest of my 30 minute commute

32F heater used 2.5kW to start and then dropped to 1.5kW after a few minutes then dropped to ~ 0.75kW for the rest of my 30 minute commute

40F heater used 1.5kW to start and then dropped to 1kW after a few minutes then dropped to ~ 0.5kW for the rest of my 30 minute commute

48F heater used 1.5kW to start and then dropped to 0.5kW after a few minutes then toggled between 0 and ~0.5kW for the rest of my 30 minute commute

Click to expand...

Interesting - thanks for keeping the data. Looks like a great improvement. I haven't experienced really cold wx in my 2011, and have not kept records, but that 40° report looks like less than half of what I would see.

Yeah, looks pretty good. With my '11, even in 50F temps around here, in ECO mode with HVAC pulling 1.5 kW for 20-30 minutes set to 72F, it never really fully warms up.

It looks like the heat pump around here would basically get us heat for a nearly negligible amount of energy.

I want a heat pump!!!! On the bright side I had a first yesterday, the wife opted for no heat instead of going to go back for the gasser. Made it home on VLB thanks to everyone on this site so I knew how far I could go.

MatimalND said:

I want a heat pump!!!! On the bright side I had a first yesterday, the wife opted for no heat instead of going to go back for the gasser. Made it home on VLB thanks to everyone on this site so I knew how far I could go.

Click to expand...

Sounds like you've trained her well
It took awhile, but my wife has finally learned not to question/complain about my climate control choices in the Leaf

I wonder how it would keep up in say a 15 degree Fahrenheit environment, temperature at the vents. I'm guessing with the 3KW value that the resistive heater was supplementing for a few minutes, it's hard to believe a car heatpump would take that much. More realistic that 1.5KW is the power it takes when the compressor is at full speed.

If so I wonder if it's possible to completely disable the resistive heater without making the car angry (remove a fuse?)

bradbissell said:

So far all data has been with Eco mode since that seems to produce heat perfectly well with the heat pump. Heat is nearly instantaneous when started.

...
28F heater used 3kW to start and then dropped to 1.5kW after a few minutes then dropped to ~ 1kW for the rest of my 30 minute commute

32F heater used 2.5kW to start and then dropped to 1.5kW after a few minutes then dropped to ~ 0.75kW for the rest of my 30 minute commute

Click to expand...

In ECO mode heater should never use more that 2kW... So how those 2,5-3kW values were possible?
Also doesn't looks too impressive :/ MY12 also used about 1,5kW after some preheating (in beginning of driving) on higher powers. Only at -20C it continuosly used about 3kW, at -10C something about 2kW.

1KW of consumption isn't that bad if you think of the heatpump possibly outputting 15,000 BTUs or so into the cabin. Assuming 17 SEER efficiency (pretty efficient but not particularly high-end), 15,000 BTU /17 SEER= 882 watts which leaves 118 for the cabin fan and radiator fan. Those numbers are just an example of how 1KW might add up.

15,000BTU is about 4,400 watts if using a resistive heater.
http://www.rapidtables.com/convert/power/Watt_to_BTU.htm" onclick="window.open(this.href);return false;

danwat1234 said:

I wonder how it would keep up in say a 15 degree Fahrenheit environment, temperature at the vents. I'm guessing with the 3KW value that the resistive heater was supplementing for a few minutes, it's hard to believe a car heatpump would take that much. More realistic that 1.5KW is the power it takes when the compressor is at full speed.

If so I wonder if it's possible to completely disable the resistive heater without making the car angry (remove a fuse?)

Click to expand...

3 kW is not surprising at all at initial start on a fairly cold day.
The AC will pull 3kW for a short period of time on a very hot +95F day.
Appears the heat pump performance is pretty impressive, on par with the AC relatively modest kW demand, compared to the 2011 / 2012 / 2013S energy hog resistive heat.

As has been discussed elsewhere here, the downside is that if you are in an area that primarily uses AC and not heat, the 2013 HVAC is actually notably less efficient than the 2011 and 2012...
To make it more efficient would have required an intelligent proportional valve that would cost as much as the entire system. We learned this at the Nissan meeting in Phoenix in August...

That sounds kind of crazy. I'll search around later and if I find info about that I'll post here.

EIDT: Anybody know how the Leaf and other heatpump EVs defrost the evaporator radiator (cold side, by the front grille)? With normal household heatpumps the heatpump turns into an air conditioner without the radiator fan being on, and resistive heat comes on to keep warm air coming out of the vents. Usually they run a defrost every 45 minutes to an hour or so. But with a moving vehicle, how could the compressor raise the radiator enough above freezing on a very cold day to defrost it and it would take longer too? Only active grille shutters might do the trick but that might not be enough at freeway speeds.
Hmm.

EDIT: 1 thread briefly mentioning 2013 Leafs using more power for AC but no details at all, by user 'dgpcolorado'.
http://www.mynissanleaf.com/viewtopic.php?f=6&t=13528" onclick="window.open(this.href);return false;

I've been really intrigued by those "super hydrophobic" coatings, and wonder what would happen if you applied them to the evaporator (cold) side of the heatpump. Would the water/ice tend to just drop off?

danwat1234 said:

...EDIT: 1 thread briefly mentioning 2013 Leafs using more power for AC but no details at all, by user 'dgpcolorado'.
http://www.mynissanleaf.com/viewtopic.php?f=6&t=13528" onclick="window.open(this.href);return false;

Click to expand...

LEAFfan was the first to report higher power usage by the AC in his 2013 versus his previous 2011 LEAF. I don't know if anyone has rigorously measured the difference but the LEAF energy screen reportedly shows a substantial difference to someone familiar with both cars.

In retrospect, it doesn't seem surprising that a heat pump used for both heating and cooling would be less efficient than the dedicated AC unit used in 2011/2012 and 2013 S model LEAFs.

It is possible Nissan decided to take the hit on the AC side - heating side in '11/'12 is downright a pig. It sucked a good 15-20% of the range - leaving us with sometimes half the range we get in summer (city in summer vs freeway in winter).

TomT said:

As has been discussed elsewhere here, the downside is that if you are in an area that primarily uses AC and not heat, the 2013 HVAC is actually notably less efficient than the 2011 and 2012...
To make it more efficient would have required an intelligent proportional valve that would cost as much as the entire system. We learned this at the Nissan meeting in Phoenix in August...

Click to expand...

Thanks TomT, first I've heard of this or of Nissan discussing not including very expensive proportional valve at the August Phoenix meeting.
Was this mentioned on MNL? Do you have the link?

I just got off the phone from somebody at Nissan regional consumer affairs and they don't know how or if the car can defrost the evaporator coil automatically by running the heatpump in AC mode for a while with the fan off (needed for long cold humid weather trips bouncing off fast chargers)... or how it prioritizes defogging the windows by running the heatpump in AC mode and using the resistive heater to keep the air kind of warm, versus just using the heatpump when no defogging is needed..
Oh well

I was at the Phoenix meeting, and I don't remember anything about a "Proportional Valve". Since the heat-pump equipped LEAF's have a separate evaporator coil for heat, there are also separate expansion valves (orifice type) so each can be optimized for the expected deltas. On ultra high-performance heat pumps they use a computer controlled expansion valve, but this only increases efficiency marginally, and I can see why in the heavily cost-optimized LEAF why Nissan omitted it.

I'd have a hard time believing that the addition of the heat pump affects A/C mode efficiency over a few percent.

-Phil

Tonight here in Cincinnati we're suppossed to get to -3 for the low. So far the '13 leaf I have does fine for heating. If I dont pre-heat I'll see usually 3~4kw of usage for about 5 to 10 minutes then it stays around 1.5kw after that for a little longer until the car hits temperature. I can usually get about 60+ miles highway to VLB with the heater on this cold from Hamilton to Milford and back.

We have had a few warm days since I picked up the 2015 SL and I cannot see any difference in energy consumption in cooling mode compared to the 2011 by looking at the energy use screen on the NAV system. Cooling is better than the 2011 was after software updates reduced A/C output when sitting still or moving less than 18 mi/hr.

Energy consumption when heating has been greatly reduced for our moderate temperatures. So far, I really like the heat pump hybrid system.

Gerry

How do I know when the heat in my 2013 S is coming from the Heat Pump? How do I "force" it to use the heat pump, particularly in 20F to 50F weather, when a heat pump is probably the best way to heat?

Is the heat pump actually controlled by the "AC" buttonand the temperature setting (is this what turns on the heat pump? versus "Heat" being the resistance heat? Or can I only choose "Heat" and the car picks between heat pump and "the heater"?

I'm trying to evaluate the gains from having more spot heat (12v resistive heating, say, along the base of the windshield and under the driver's feet) versus running a heat pump in heat mode.

Generally, running a heat pump is more efficient than resistance heat, unless the resistance heat is very carefully applied.

Heated seats and steering wheel is an example of a successful, efficient application of resistance heat. The traditional Leaf "Heater" is an example of what not to do.

But as Boston winter sets in, I'm faced with needing to heat the windshield (to keep my breath from fogging) and needing to keep my feet warm. Let's say I ran another 200W worth of resistive heating tape or pads to those points....at some point, I'd be better off actually running the heat pump rather than taping every surface of the car for resistance heat.