Electric car heat! Liquid?

[Funny]

I agree with TestDrive, you should reassemble the unit and test whether ethylene glycol is compatible with it, at the same time testing what temperature it will ultimately reach. If it reaches 200 F in a reasonable time, you could use it to heat a smaller reservoir and have that bleed into a larger reservoir for a longer lasting defrosting capability.

Like this: (sorry about the crudeness of the picture)
Tank heater setup (Small).bmp

[bennelson]

More playing with the Mr. Tea....

I put the heating element back in the shell and then removed the top, to access the internal "exit" tube. I pulled that and looped it so that the heated water would just squirt back into the cold water resevoir, instead of having to go to an external cup, make a mess, loose heat, etc.



I filled the machine with could water. It holds a little less than a quart.

I flipped the machine on, with the exit hose pinned down and a kitchen thermometer held in place in the water resevoir.



I set a timer and checked the temperature as it went up.

Here's the temperatures in ℉. after various times.

3 mins: 140℉
4 mins: 160℉
6 mins: 185℉
7 mins: 196℉
8 mins: BOILING! Ack! Why did I turn away from my experiment right then! It started squirting all over my kitchen! :


The thermo-cut-off never cut in. I think it is only designed to turn off power at something like 400 degrees.
Again, I am only experimenting right now for fun, and to see how all this might work.

I think it shows that a heater element like this one has plenty of power to heat water or anti-freeze to significant temperatures!

A system actually installed for heat in an electric car would need a separate on/off switch, safety cut-off, and likely a pressure relief of some sort.

I did NOT do this experiment with anti-freeze because it costs more, is messy, and I don't want to use my only kitchen (FOOD) thermometer in anti-freeze!

As to compatibility of anti-freeze with the Mr. Tea, what's the concern? It's an aluminum tube. Aren't there lots of aluminum parts on cars nowadays? Do those cars require special coolant?

[MazdaMatt]

I love how you made the connection between 120V 2gal heated container and church coffee pot. Nicely done.

As for the "obscure square" screw used to deter tampering tinkerers... its called a robertson (as opposed to phillips) and its a Canadian thing - not some obscure oddball fastener. And we'll have you know that it is a superior screw in every way

[Funny]

Originally Posted by MazdaMatt

As for the "obscure square" screw used to deter tampering tinkerers... its called a robertson (as opposed to phillips) and its a Canadian thing - not some obscure oddball fastener. And we'll have you know that it is a superior screw in every way

I just thought I'd burst your bubble and remind everyone that in all circuit breaker panels in the US, they use robertson screws to connect all the grounds to a common bar. Sorry .

In fact I think almost all countries that use 110/220V or 115/230V setups have this "unique" screw.

[TestDrive]

Originally Posted by bennelson

As to compatibility of anti-freeze with the Mr. Tea, what's the concern? It's an aluminum tube. Aren't there lots of aluminum parts on cars nowadays? Do those cars require special coolant?

I wasn't thinking of Mr. Tea's compatibility with anti-freeze.

Imagine something unexpected comes up and the car is parked out in cold for several days. Straight water would freeze => expand => burst heater core & reservoir tank(s). A 50/50 antifreeze mix will protect from freezing and will have a higher boiling point than water, maybe the higher boiling point is sufficiently high to actuate cut-off switch? If so, it might simplify design.

If you pressurize the system (with a standard radiator cap), that would further raise the boiling point. Maybe the combined effect of 50/50 antifreeze and increased system pressure is both necessary and sufficient to trigger the cut-off switch?

The hotter the liquid stored in the reservoir, the longer it will be effective.

[asfd]

You should have a look at paraffin as a heat storage medium. It can store heat much more effectively than water in the form of latent heat when heated (melted). I quick read a document on that topic whre it says that
"The paraffin shows the best performance (of their test), with a useful thermal storage density of more than 2 times that of water.".
Paraffin is also cheap, non-toxic and readily available.

Regards,

[bennelson]

Of course for use in the car, anti-freeze would be used, not straight water!

I have heard that paraffin can hold more heat energy, but I would hold off on experimenting with that. I am just trying to play with some basics here. I already know the car is designed to run antifreeze through the heater core, so modifying a heating system based on that is pretty straight forward.

[IndyIan]

I'm sorry to break it to you but you can't store a useful amount of heat in 2 gallons of water. I figured about 2000 btu, given 8kg of water, 60 deg C temp drop. Maybe something like a 20kg block of iron at 400C? gives you a much greater change in temp. Probably need expensive insulation though...

Probably your best bet is just get warm clothes, -100 boots, a real parka, and some sort of snow pants will have you hot enough that you won't need thick gloves to drive.
Also, how do you keep your windshield clear? Maybe you could install the rear window heating elements on the front window?

Or you could track down a volkswagon gasoline heater... Or install a small propane heater like this:


We have one with a hose for a bbq tank we use for ice fishing, runs for 48-110 hours depending on the setting. Has an 02 sensor that shuts it off if oxygen is getting low and also shuts off if you knock it over.
Ian

[MazdaMatt]

He isn't just bringing a 2gal jug of hot water with him... he'll be running 2gal of hot water through the heat exchanger while keeping it hot, thereby warming the entire car... which WILL hold its heat for a while.

Funny, i realize the robertson is used outside of canada, and I've been rewiring my whole house, so i see that it is the standard with electrical, but it was invented by a canadian and is used mostly here in canada. Read the wiki page

[Funny]

Point taken .

I am surprised that more triangle bits aren't used, as you can really torque the b-Jesus out of them.