Exhaust heat recovery for PHEVs

[Daox]

Interesting idea, not unlike something we here on EM have come up with.

Even Better Gas Mileage For Plug-In Hybrids? Look To Heat Recovery

The system passes the hot exhaust gasses over pipes containing Pentafluropropane--a hydroflurocarbon refrigerant known as R-245fa--transferring thermal energy from the exhaust into the refrigerant.

Because it has a lower boiling point than water, the refrigerant expands, turning into a vapor that can power a turbine to generate electricity.

After passing through the turbine, the refrigerant is then condensed back into its liquid form before recirculation.

...

Already, the researchers say they have recovered up to 10 percent of engine waste heat under highway driving conditions using a prototype plug-in hybrid designed by Ohio State University.

That translates to a potential 1.9 kilowatts of electrical power, or a 7 percent improvement in gas mileage.

[ksa8907]

bout time somebody makes use of all that "waste" energy.

[serialk11r]

Depending on the weight penalty, that could be anywhere from rather good to meh. Still, better than nothing, hopefully these become commercially available, as they're rather difficult to DIY. Thermoelectric units are not producing acceptable power levels at all.

[cRiPpLe_rOoStEr]

An uncle of mine already considered to make a cab cooling setup for his Pontiac Trans Sport, using the exhaust heat to expand a refrigeration gas just like those old kerosene-powered fridges still often used in rural places in the 3rd-world.

[Cobb]

As a hybrid owner the climate control is also hybrid, half cold and half warm. Use of the heater on the newer insight limits if not eliminates the auto stop feature at stops and also the very limited ev mode and at times even the fuel cut off coasting.

When I drive my Insight in the winter its fully dressed in a heavy coat and a jon-e pocket heater in my shirt pocket, otherwise I can kiss 60+ mpg goodbye.

[cRiPpLe_rOoStEr]

Originally Posted by Cobb

Use of the heater on the newer insight limits if not eliminates the auto stop feature at stops and also the very limited ev mode and at times even the fuel cut off coasting.

That makes the heating feature quite pointless. Maybe one of those 12-volt aircraft cab heaters would be more reasonable.

[Cobb]

Having the IMA and phev vent into the cabin does help, but it takes over an hour for that to build. I use to use one of those small 300 watt accessory plug heaters when I had to wait for a ferry an hour a day. It wouldnt heat the car, but kept the temp comfortable with the engine off. Too much of a load and it takes from the mpg as the engine has to put it back into the ima battery.