I have had this idea for ages but never gotten round to doing something about it, so I thought I'd pass it by you lot. I have plenty of experience in the industrial sector recovering waste heat & putting it to good use elsewhere, its easily done & some basic engineering could see the idea to fruition.
Basic Idea
Recover the excess heat that our highly inefficient IC engines produce as waste. eg about 70% of the fuel used is wasted as heat.
The recovery system uses a large mass of high latent heat transfer material - eg parrafin wax that can be stored relatively safely in an LPG gas type container safely fixed in the boot of the car. Some simple pipework transfers the heat from the engine coolant to the wax & even exhaust heat could be recovered with a heat exchanger.
Once the heat is transferred on your commute you potentially have a large store of free heat, plug your car into your house heating system etc.
Pros
Free heating with some additional quick release plumbing from car to home
No need for radiator ducting all the time so aero advantages etc
Cons
Extra weight to lug around
Safety issues
What to do when the wax mass becomes saturated with heat
Need to know
How much wax mass required for vehicle type & size v typical commute etc
Fuel savings with aero mods available
How to engineer a fail safe etc
So over to you guys to do some maths & calculations
if you thinks its viable I'll happily re engineer my Lupo 3L 1.2 Tdi or someother car I have about to experiment with.