Becoming ever more important in auto technology. Satellites use heat from decaying elements to power electrical components…or so I believe.

Engines generate enough heat to make manifolds glow, can this be recovered and fed into the battery systems that are becoming more prevalent on modern cars?

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator for the first line.

i guess they could use peltier devices to produce electrical energy from the waste heat. though keeping the cool side cool would require quite a bit of heatsinking.

JudgeMental said:

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator for the first line.

i guess they could use peltier devices to produce electrical energy from the waste heat. though keeping the cool side cool would require quite a bit of heatsinking.

An extra radiator? Car makers are good at cooling.

AwesomeO said:

Becoming ever more important in auto technology. Satellites use heat from decaying elements to power electrical components…or so I believe.

Engines generate enough heat to make manifolds glow, can this be recovered and fed into the battery systems that are becoming more prevalent on modern cars?

Cost effectiveness is probably the main thing.

The bits hanging off the modern ICE are quite effective at what they do.

heat tends to be a fairly difficult to use form of energy, unless you have a lot of it. Not sure if a car engine has enough to be useful.

thing is peltier devices are about 5mm thick so that is the distance between the hot side and the cold side. makes fitting the cooling, maybe, hard.

party_pants said:

heat tends to be a fairly difficult to use form of energy, unless you have a lot of it. Not sure if a car engine has enough to be useful.

Turbo manifolds get to above 800c.

One of these works quite well to improve the efficiency of an engine, by extracting energy from the exhaust gases.

Spiny Norman said:

One of these works quite well to improve the efficiency of an engine, by extracting energy from the exhaust gases.

True, and now they are recovering energy from brakes, so just wondering about all that lovely waste…or discarded heat.

AwesomeO said:

Spiny Norman said:

One of these works quite well to improve the efficiency of an engine, by extracting energy from the exhaust gases.

True, and now they are recovering energy from brakes, so just wondering about all that lovely waste…or discarded heat.

I’m a bit of a fan of instead of using friction brakes, use small motors attached to the wheels to do stuff like generate electricity or compress air, etc, to use to accelerate the car later on. Makes for less heat but it’s a bit tricky to do.

AwesomeO said:

party_pants said:

heat tends to be a fairly difficult to use form of energy, unless you have a lot of it. Not sure if a car engine has enough to be useful.

Turbo manifolds get to above 800c.

From what I understand, satellite heat-based power supplies are fairly low power because they are inefficient. Only a few dozen or a couple hundred watts at best. About the same as a power drill or a sander. The extra weight might not be worth such a small amount of extra power.

AwesomeO said:

Becoming ever more important in auto technology. Satellites use heat from decaying elements to power electrical components…or so I believe.

Engines generate enough heat to make manifolds glow, can this be recovered and fed into the battery systems that are becoming more prevalent on modern cars?

satellites overridingly use solar cells to generate the power they need – I’ve never heard of radioactive isotopes being used for them – maybe military vehicles perhaps?

space vehicles moving away from the sun or will be in a deep cold of a lunar night might use stuff like plutonium or polonium 210

voyager uses plutonium to generate heat that can be used to create electrical power

jjjust moi said:

AwesomeO said:

Becoming ever more important in auto technology. Satellites use heat from decaying elements to power electrical components…or so I believe.

Engines generate enough heat to make manifolds glow, can this be recovered and fed into the battery systems that are becoming more prevalent on modern cars?

Cost effectiveness is probably the main thing.

The bits hanging off the modern ICE are quite effective at what they do.

I would use the heat from the exhaust to increase the pressure in the air con system to make it more efficient

JudgeMental said:

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator for the first line.

i guess they could use peltier devices to produce electrical energy from the waste heat. though keeping the cool side cool would require quite a bit of heatsinking.

the cool side just need to be shaded effectively I’d say

things are fairly cold in space without being warmed by the sun

Spiny Norman said:

AwesomeO said:

Spiny Norman said:

One of these works quite well to improve the efficiency of an engine, by extracting energy from the exhaust gases.

True, and now they are recovering energy from brakes, so just wondering about all that lovely waste…or discarded heat.

I’m a bit of a fan of instead of using friction brakes, use small motors attached to the wheels to do stuff like generate electricity or compress air, etc, to use to accelerate the car later on. Makes for less heat but it’s a bit tricky to do.

I’d go the purely mechanical way by using compressed air, batteries tend to die quickly and are very heavy

i was talking about using peltiers for the car not satellites.

party_pants said:

AwesomeO said:

party_pants said:

heat tends to be a fairly difficult to use form of energy, unless you have a lot of it. Not sure if a car engine has enough to be useful.

Turbo manifolds get to above 800c.

From what I understand, satellite heat-based power supplies are fairly low power because they are inefficient. Only a few dozen or a couple hundred watts at best. About the same as a power drill or a sander. The extra weight might not be worth such a small amount of extra power.

they can be quite heavy

JudgeMental said:

i was talking about using peltiers for the car not satellites.

a solar cell would be more efficient than a peltier device

wookiemeister said:

Spiny Norman said:

AwesomeO said:

True, and now they are recovering energy from brakes, so just wondering about all that lovely waste…or discarded heat.

I’m a bit of a fan of instead of using friction brakes, use small motors attached to the wheels to do stuff like generate electricity or compress air, etc, to use to accelerate the car later on. Makes for less heat but it’s a bit tricky to do.

I’d go the purely mechanical way by using compressed air, batteries tend to die quickly and are very heavy

The latest electric cars from Tesla have about a 500 km range. Lithium batteries aren’t too heavy either but yes they take up a bit of space.

Anyway here’s an air car I quite like.
Peugeot experiment

Spiny Norman said:

wookiemeister said:

Spiny Norman said:

I’m a bit of a fan of instead of using friction brakes, use small motors attached to the wheels to do stuff like generate electricity or compress air, etc, to use to accelerate the car later on. Makes for less heat but it’s a bit tricky to do.

I’d go the purely mechanical way by using compressed air, batteries tend to die quickly and are very heavy

The latest electric cars from Tesla have about a 500 km range. Lithium batteries aren’t too heavy either but yes they take up a bit of space.

Anyway here’s an air car I quite like.
Peugeot experiment

yeah the buggers “nicked” my idea, I put forward this notion here a while back in a similar conversation

air pressure would be great for purely stop start situations using a ICE.

once we see a marked improvement in battery tech I’d say we’ll see ICE go the way of the dinosaur for personal transport

JudgeMental said:

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator for the first line.

i guess they could use peltier devices to produce electrical energy from the waste heat. though keeping the cool side cool would require quite a bit of heatsinking.

I think that peltier devices are for utilizing electrical energy to generate temperature differences, rather than the other way around.

There are thermoelectric energy recovery systems around, like Hi-Z, but the efficiency is miniscule.

For heat engine type recovery systems, the efficiency limit is set by E =1- T1/T2 where T1 is the sink temperature and T2 is the source temperature in an absolute scale such as Kelvin.

The proportion of energy dumped in the exhaust gas in an ICE is around 40% of the fuel input.

If we take an exhaust temperature of 400C (red hot) and a discharge temperature of 110C (above condensation), then we might theoretically achieve an efficiency of around 30%. So 30% of 40% is 12%. Worthwhile, I suppose.

Just attempting to put some flesh on the bones.

wookiemeister said:

party_pants said:

AwesomeO said:

Turbo manifolds get to above 800c.

From what I understand, satellite heat-based power supplies are fairly low power because they are inefficient. Only a few dozen or a couple hundred watts at best. About the same as a power drill or a sander. The extra weight might not be worth such a small amount of extra power.

they can be quite heavy

The satellite ones are heavy because they need to shield the nuclear material. One of them mounted to a car exhaust or turbo charger wouldn’t be quite so heavy of course, but its power output would still be only about enough to power a drill. That amount of extra power applied to a car might not be noticeable given the weight of a car.

wookiemeister said:

Spiny Norman said:

wookiemeister said:

I’d go the purely mechanical way by using compressed air, batteries tend to die quickly and are very heavy

The latest electric cars from Tesla have about a 500 km range. Lithium batteries aren’t too heavy either but yes they take up a bit of space.

Anyway here’s an air car I quite like.
Peugeot experiment

yeah the buggers “nicked” my idea, I put forward this notion here a while back in a similar conversation

air pressure would be great for purely stop start situations using a ICE.

once we see a marked improvement in battery tech I’d say we’ll see ICE go the way of the dinosaur for personal transport

I’ve been hanging out for graphene-based batteries for a while, they show good prospects.

The conventional car thing is really interesting, I use my 3.2 litre diesel Pajero as an example. Around town it averages about 11 l/100 km. On the highway on flat ground it’s not difficult to get into the low 7’s. Pull the speed back to about 80 km/h and I reckon mid to low 6’s would be possible and that’s impressive for a 2.4 tonne square-ish lump. The bit that really sucks down the fuel is accelerating it ….. so if there was a way to recover the energy from slowing it down to use again it was get a rather good overall average consumption figure – And that’s what the Peugeot air car does. The petrol engine is quite small and is pretty much just used for constant speed type driving with the air motor used to accelerate it, and turn into a compressor when slowing.

morrie said:

JudgeMental said:

http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator for the first line.

i guess they could use peltier devices to produce electrical energy from the waste heat. though keeping the cool side cool would require quite a bit of heatsinking.

I think that peltier devices are for utilizing electrical energy to generate temperature differences, rather than the other way around.

There are thermoelectric energy recovery systems around, like Hi-Z, but the efficiency is miniscule.

For heat engine type recovery systems, the efficiency limit is set by E =1- T1/T2 where T1 is the sink temperature and T2 is the source temperature in an absolute scale such as Kelvin.

The proportion of energy dumped in the exhaust gas in an ICE is around 40% of the fuel input.

If we take an exhaust temperature of 400C (red hot) and a discharge temperature of 110C (above condensation), then we might theoretically achieve an efficiency of around 30%. So 30% of 40% is 12%. Worthwhile, I suppose.

Just attempting to put some flesh on the bones.

ahhhhhhhhhh yes

peltier is cooling

the seebeck effect is generating power

Spiny Norman said:

wookiemeister said:

Spiny Norman said:

The latest electric cars from Tesla have about a 500 km range. Lithium batteries aren’t too heavy either but yes they take up a bit of space.

Anyway here’s an air car I quite like.
Peugeot experiment

yeah the buggers “nicked” my idea, I put forward this notion here a while back in a similar conversation

air pressure would be great for purely stop start situations using a ICE.

once we see a marked improvement in battery tech I’d say we’ll see ICE go the way of the dinosaur for personal transport

I’ve been hanging out for graphene-based batteries for a while, they show good prospects.

The conventional car thing is really interesting, I use my 3.2 litre diesel Pajero as an example. Around town it averages about 11 l/100 km. On the highway on flat ground it’s not difficult to get into the low 7’s. Pull the speed back to about 80 km/h and I reckon mid to low 6’s would be possible and that’s impressive for a 2.4 tonne square-ish lump. The bit that really sucks down the fuel is accelerating it ….. so if there was a way to recover the energy from slowing it down to use again it was get a rather good overall average consumption figure – And that’s what the Peugeot air car does. The petrol engine is quite small and is pretty much just used for constant speed type driving with the air motor used to accelerate it, and turn into a compressor when slowing.

have a look in the other forum I frequent

heat from the exhaust would be more effectively reclaimed to pressurise the air con system

peltier is heating or cooling depending on which side you consider waste.

the other option is making the car half the weight

energy required to accelerate would drop

the brakes would last longer

the car would do less damage – it might be able to crash through walls and kill people

you would need a sophisticated head on crumple system though

JudgeMental said:

peltier is heating or cooling depending on which side you consider waste.

mostly cooling is when its used

wookiemeister said:

heat from the exhaust would be more effectively reclaimed to pressurise the air con system

Not needed. It’s just pumped up to whatever pressure they run and that’s it.
The gas has to be cooled with a little radiator in the front of the car to stop it overheating, and of course to keep the pressure under control.

Spiny Norman said:

wookiemeister said:

heat from the exhaust would be more effectively reclaimed to pressurise the air con system

Not needed. It’s just pumped up to whatever pressure they run and that’s it.
The gas has to be cooled with a little radiator in the front of the car to stop it overheating, and of course to keep the pressure under control.

http://www.solairworld.com/

The Next Generation Solar Thermal Hybrid Air Conditioners take the improvements made by inverter technology to the next level. By capturing thermal (ambient) energy, the amount of work the condenser does is reduced under full load and significantly extends the time the compressor is cycled off.

The solar collector absorbs thermal solar energy by using a thermal collector with copper heat conducting inner coils. This then uses the stored energy in the solar collector to continue the refrigeration cycle while the compressor is off, utilising a larger stored amount of refrigerant liquid in the condenser.

The collector, compressor and the condenser have been designed to work in tandem to allow a smaller compressor to be used. The smaller compressor consumes less electricity and combined with the solar collector, SolAir World’s air conditioners optimise energy savings and reduce running costs.

Simply put, the hotter it gets, the more energy is collected in the thermal hybrid collector,

the more efficient the system becomes.

cars would never have been so cool inside

JudgeMental said:

peltier is heating or cooling depending on which side you consider waste.

but is doesn’t generate electrical energy from temperature differences. Rather, the reverse.

yep, you need the thermoelectric effect instead not peltier.

the peltier is a power consuming device

the seebeck is a power generating device

morrie said:

JudgeMental said:

peltier is heating or cooling depending on which side you consider waste.

but is doesn’t generate electrical energy from temperature differences. Rather, the reverse.

This is true; the complementary effect (converting heat directly into electricity) is the Seebeck effect