Exhaust Heat Recovery - Steam Power

[vacationtime247]

How to collect and use wasted potential energy. A few ideas I had rolling around my head was a front wheel drive engine / rear wheel powered compressed air drive. Engine cut off and free wheel front drive unit at take off where most fuel is burned. Using rear compressed air to accelerate the vehicle to even a modest speed of say 30-40 mph would save a considerable amount of fuel. Front engine would turn on and continue to propel as normal. Perhaps use a turbo to provide the compression when decellerating (EOC?) as the turbo would continue to spool. Not sure if the additional weight added would provide a benefit. Engine would be a small turbo diesel.

Modify the transmission design to compress fluid and drive only the tranny at initial take off. Car would use the compression drive to fill only when braking, to provide additional stopping assistance and allow the engine to freewheel.

Best solution would be to design a better propulsioning system / engine. The piston design is archaic. The piston design can only provide power through 45 degrees of it's 360 degree rotation. Diesel engineers now pulse the injector several times during the power stroke to maximize this short range of potential.
VT247

[arcosine]

The jet is not the most efficient steam engine, since kinetic energy is lost when the wheel spins and when the jet is deflected off. I wonder if a simple oscillating piston and cylinder would work, the piston has a rare earth magnet and the cylinder has a coil wrapped around it, of course a turbine would be cool. I wonder if one could use the AC compressor as the heat engine and freon as the working fluid.

[IamIan]

Sadly I begin to suspect that the only way to not have a prohibitive amount of water weight to carry around would be to have a closed system design.

I found an example of a steam engine:

Our shop unit has been in use for the last 18 years producing 4000 watts an hour. It consumes about 250 pounds of water (that has been turned to steam) in one hour. 750 watts is considered one horsepower, and when you figure efficiency losses, that works out to about 47 pounds per horsepower hour (250 lbs divided by roughly 5.3 horsepower). Put another way, for every horsepower the engine produced, we evaporated 47 pounds of water to steam and passed it through the engine.

250 pounds of water per hour to get 4 kwh out of the steam engine just puts some harsh weight restrictions on the amount of water that needs to be carried around.

If a closed system to recover the water vapor is too complicated / heavy ... perhaps as others have suggested a straight heat engine like a Sterling that just needs a temperature difference would work better... no water would need to be consumed.

Some useful books for learning more about Stirling:
http://www.freebookspot.me/Comments....ement_ID=23810
http://www.freebookspot.me/Comments....ement_ID=23809

[stovie]

Check out this website it might give u some more idea's

Cyclone Power Technologies - WHE Waste Heat Engine Systems

[Piwoslaw]

While researching info on new efficiency technologies in trucks, I found that the concept Iveco Glider uses a steam system to harness energy from the radiator and exhaust:

Thermo-dynamic laws do not allow an engine to transform fully the heat generated by combustion into kinetic energy and part of this heat is lost to the atmosphere. The radiator and the exhaust system release this waste heat into the atmosphere. With Iveco Glider, the heat of the exhaust gases is instead turned into electricity thanks to a thermo-dynamic system based on a Rankine cycle, a sort of compact and efficient steam machine. A high efficiency heat exchanger is positioned in the exhaust line immediately after the emission control system and it is used to pressurise an organic working fluid capable to operation also at low ambient temperatures. The heat that is not turned into energy is dissipated also thanks to the planar heat exchangers that operate the side fairings of the Iveco Glider, while a by-pass valve makes it possible to exclude the system during maximum power requests. The heat recovery system helps reduce the vehicle's fuel requirements by up to 10% on motorway missions.

[Daox]

Looks like someone took this idea and ran with it. Debuted at the Frankfurt show, Eberspaecher has designed a system to capture exhaust heat and spin a turbine with steam to produce electricity for automobiles. They also talk about a thermoelectric generator (TEC, peltier) and a heat accumulator that can heat up the CAT in seconds for a 95% reduction in cold start emissions.

Exhaust System Good For More Than Hot Air

One of the technologies is a mini steam power plant designed to be plugged into the exhaust stream. Residual exhaust heats water within the unit until it vaporizes and drives a turbine blade. The resulting energy can be used mechanically or to generate electricity.

...

In a passenger-car application, the supplier says the potential power generation lies between 800 and 1,100 watts, which corresponds to a carbon-dioxide reduction of about 10 g/km.

[NeilBlanchard]

Is it a closed system, or is the water lost as you drive?

[Daox]

Well, since they mention the Rankine cycle, I'm assuming it has to be closed loop.

[ConnClark]

I found this while websurfing today.


Infinity Turbine ® - Organic Rankine Cycle Model ITxr Kit

you can't run it directly off your exhaust but you can hook it to a closed loop system or maybe a single pass system. This company suggests using it with a closed loop organic rankine cycle using refrigerant as the working fluid. They also say you can recover heat from the radiator alone.

[basslover911]

Originally Posted by ConnClark

I found this while websurfing today.


Infinity Turbine ® - Organic Rankine Cycle Model ITxr Kit

you can't run it directly off your exhaust but you can hook it to a closed loop system or maybe a single pass system. This company suggests using it with a closed loop organic rankine cycle using refrigerant as the working fluid. They also say you can recover heat from the radiator alone.

THAT is cool! how much is it?

You could simply wrap a coil of copper ALLL around your exhaust pipe and route it to this.