Open Source EV Cabin Heater - Feasible? Best Approach?

[MitchJi]

Hi,

If this is feasible it could make a substantial difference for EV comfort and range. For the Model S Consumer Reports states that:

Drawbacks include tight access, restricted visibility, and range limitations in cold weather.

So this idea could make a substantial difference, even in EV's with huge packs.

The following is based on a post, a long time ago (I don't remember where but not ES), in which someone stated that he heated his EV with a DeLonghi Oil Filled Radiant Heater, then on his commute to work the stored heat maintained the passenger compartment at a comfortable temperature.

Most or all modern EV's have the ability to preheat or cool the passenger area, while they are connected to the grid. If they heated or cooled something with sufficient thermal mass to use stored heat, to maintain a comfortable temperature for as long as necessary, the space heating would have no impact on the vehicles range. The amount of stored heat, required, would depend on, among other factors, on the range of the car. A fringe benefit would be that radiant heat is a very comfortable type of heat.

What I envision is an insulated box, or boxes with containers filled with either a phase change material which seems like a good match for EV heater use, or something simpler, like oil if that will work well enough.
http://sustainabilityworkshop.autodesk.com/buildings/thermal-mass

Phase change materials are a relatively new class of materials, which are used to add thermal mass without adding weight or bulk. They may replace standard wall board, or may be an additional layer in walls or floors. They are relatively rare but quickly increasing in popularity as technologies improve and prices drop.

In addition to compactness and light weight, phase change materials absorb and release their heat at certain temperatures, just as water boils at a certain temperature. This helps occupied spaces stay at the temperature desired, even as heat is flowing in or out of the space.

The insulated box(s) would have vents, which could be opened and closed. One way this could be used is that the thermal mass could be heated at night, with the vents closed. In the morning the cabin could heated by opening the vents while it's still connected to the grid (the normal space heating would probably be superfluous). Then the vents would be opened sufficiently to maintain a comfortable temperature for your morning drive, then closed when you arrive at your destination, then opened again in the evening, with hopefully sufficient stored heat to maintain a comfortable temperature for your return home. If necessary fans could be used to extract hot or cold air more rapidly.

Is this Feasible?:
Is it possible, and is the solution affordable, to store sufficient heat to maintain a passenger compartment at a comfortable temperature, in a cold climate, for the time it takes to exhaust the batteries of a Leaf or a Model S? Would it weigh too much? Could the same storage medium be efficiently used for cooling as well as heating? Would it work well enough that OEM's could dispense with their heat pumps and in-seat heaters?

Best Approach?:
Would phase change materials be required or would a simpler approach work well? Roughly how much complexity and cost would phase change materials add to this idea? Would all (or most) of the additional complexity and cost be confined to the design?

When the Leaf was introduced I considered conveying this idea to Nissan, but I don't want it to become proprietary. Now, if it's feasible, I intend to attempt convey this idea to Tesla.

 

[LockH]

Sorta an Outdoor Guy myself, but on list of stuff to get seat/backrest electric warmer. (Might serve as more cushion-ey/pillow-ey stuff re riders comfort.)

 

[Drunkskunk]

Car heating needs to be re-though. with an ICE motor, the interior is heated by the waste heat from the motor. But electrics are too efficient. There isn't enough waste heat to go around.

Preheating works, but its wasteful and assumes that you always know when you need to go someplace, and had access to the grid where you were parked. 50% of the time I get into a car, I had no idea I was going to be driving 10 minutes before, and most of my trips out involve parking on the street someplace, or in a large parking lot.

A conventional electric heater is just turning watts directly into hot air, and warming everything in the car. Sure, your knees feel toasty, but the lost Sponge Bob action figure under the back seat is also feeling nice and toasty. Since the air is being heated, everything inside the car gets heated. Action figures don't need heat, nor does the rest of the car. A heating system that heats only the driver and passenger would waste far less energy. Heated seats and control surfaces would use far less heat, and could be adaptive, turning on only when there was someone using the seat.

And heating doesn't need to be by direct heating elements. Heat pumps are far more efficient. All they do is move energy from one place to another, so you use less power per degree of heat that you feel inside the car.

 

[vax]

I would recommend propane.
Specifically something like Webasto, but with ceramic heat storage mass.
Propane gas is actually very clean and cheap too. I use it at my summer home, converted old ZAZ-968 kerosene heater to propane. It's electronically controlled, so all I have to do is switch it on and let the electronics to the rest.

 

[svt/r&d]

X2 propane already done for golf cars etc

 

[burner1]

What about something like this?


http://www.surpluscenter.com/Electrical/Miscellaneous-Electrical/Miscellaneous-Electrical/800-WATT-12-VDC-WATER-HEATER-11-3439.axd

 

[Voltron]

Volvo uses a seperate alcohol fueled cabin heater...just throwing that into the mix.

 

[dnmun]

i use a small space heater in the car to warm it up and defrost the windows and i run it when i charge the car up before i drive.

i had not thought of using a delonghi but that would be a great idea except it is kinda big and in the way. i use a small 400-500W heater with a fan inside that will balance in front of the steering wheel and it defrosts the windshield and heats it up and warms the cabin also.

i do not use the big heater/defroster that comes stock. it consumes almost 2kW i think.

instead i have the little fan/defroster from harbor freight that plugs into the cigarette lighter plug to defrost the windshield while driving. it puts the hurt on the 12V SLA pack and i get the voltage warning light when using the defroster while driving at night with the headlights on and the windshield wipers too, and i usually have the fan running in the car defrost cycle to push fresh air across the windshield along with the defrost handgun thing.

one of my chargers i use is 120V also. but i have the other charger that runs on 240V so i run a 240V three wire extension cord to the car, the same one i charge the SLA pack with. then i use a splitter i made from a modified 3 plug power cord. i split the two 120V phases into the lower two plugs and i maintained the 240V in the top plug so i can use the 240V charger and the 120V charger and the small heater pull about the same current so they maintain a balance across the 240 at the plug easily without much current on the ground leg. but the ground has to be intact and this is not the sorta thing people should do unless they understand it, but it allows me to use my regular extension cord to drive the two chargers and the heater at the same time.