Ways a Car can be More Efficient?

[xxChrisxx]

The bose system cost more power to run that it returned because it was an active ride system that didnt require high pressure hydraulics.

However the principle of what you are saying is sound, with a passive system you would definitely get back 'something', I doubt that something would be that huge though.

 

[MacLaddy]

It's actually this question of heat to electricity transfer which brought me originally to this website, and to the final decision of returning to school for electrical engineering. It seems to me that a simple device that could absorb heat and convert it to electricity, in much the same way that photovoltaics do it, would almost be a holy grail in energy transfer.

Even if you couldn't realistically get significant energy from room temperature heat, imagine the benefits of air conditioning? It always seemed like such a waste to me that in order to remove energy, you had to expend a ton of energy.

I don't understand if any of that is possible, nor any of the physics involved, but it did ultimately drive me back to school so I am happy about that.

 

[J.ofalltrades]

I wondered what happened to that. You're right, of course (not just because we agree either lol). The trick is to make the passive system in use more efficient and to use it somewhere that has a lot of wasted energy that can be converted AND to way an efficient method to store the energy. Every system I've seen fail, failed because of one of those things. Usually the energy storing method, because let's face it, batteries (and capacitors) are heavy and the energy required to deal with the extra weight is usually more than the energy captured. That being said, the real arena I think we'll find uses for tech like this is space, where all energy is important and waste is almost taboo.

 

[mgb_phys]

I think we'll find uses for tech like this is space, where all energy is important and waste is almost taboo.

Probably not, there is lots of solar power available in space, the main problem is normally getting rid of extra energy (heat).
Mass and complexity are taboo.

 

[russ_watters]

It's actually this question of heat to electricity transfer which brought me originally to this website, and to the final decision of returning to school for electrical engineering. It seems to me that a simple device that could absorb heat and convert it to electricity, in much the same way that photovoltaics do it, would almost be a holy grail in energy transfer.

Even if you couldn't realistically get significant energy from room temperature heat, imagine the benefits of air conditioning? It always seemed like such a waste to me that in order to remove energy, you had to expend a ton of energy.

I don't understand if any of that is possible, nor any of the physics involved, but it did ultimately drive me back to school so I am happy about that.

What is being discussed in this thread, without being named, is a Peltier device: http://en.wikipedia.org/wiki/Thermoelectric_effect

If you heat one side and cool the other, it generates electricity. If you drive electricty through it, one side gets hot and the other cold.

Unfortunately, they are very inefficient.

 

[T.O.E Dream]

I think that using the kinetic energy that is being thrown out when a car brakes is important. I know that's how regenerative brakes work but what other ways can we use the recover the kinetic energy.

I agree that we need a simple device that's efficient at converting heat into electricity.

 

[T.O.E Dream]

how about more efficient wind turbines. Look at the huge kinetic energy from the wind that we can use.

 

[xxChrisxx]

The point is how are you going to make these wind turbines/impellers work only when you are braking and not when you are driving along. Also what are you going to do with this electricity when you have generated it?

 

[Lsos]

The point is how are you going to make these wind turbines/impellers work only when you are braking and not when you are driving along. Also what are you going to do with this electricity when you have generated it?

Use it to charge a battery on a hybrid, which regenerative braking already does. But wind turbines on cars...yeah, that's just not going to work too well.

 

[xxChrisxx]

I was wondering if he was going to say a hybrid charge, the reason why many things don't get included is that:

a. batteries are heavy and you lose any advantage you may gain. (as batteries become better it'll be more worth pursuing recapturing the 'little things'. because atm they have to be done with other types of more effective regenerative power)
b. you have to have a complicated transmission system that ustilises 2 inputs.I'm not trying to put down any ideas nor say they can't be done, these are just some issues that are inherent to energy regeneration.

In industry the reason they haven't been used already as that it comes down to a xxxx vs cost. and the cost is ususally prohibatively high.

 

[T.O.E Dream]

The point is how are you going to make these wind turbines/impellers work only when you are braking and not when you are driving along. Also what are you going to do with this electricity when you have generated it?

You've misunderstood me. The wind turbines are a different topic than the car braking.

I meant wind turbines in general not in a car.

 

[xxChrisxx]

Ah I see, silly me.

 

[Lsos]

a. batteries are heavy and you lose any advantage you may gain. (as batteries become better it'll be more worth pursuing recapturing the 'little things'. because atm they have to be done with other types of more effective regenerative power)
b. you have to have a complicated transmission system that ustilises 2 inputs.

Seems to me hybrids are not as much affected with the penalties of heavier weight (in regards to efficiency), simply because of the fact that that they offer regenerative braking. So yeah, it takes more energy to get the thing going, but you're going to get most of it back anyways. I'm not sure how efficient this whole process is, but it's efficient enough that hybrids are often claimed to get better mileage in the city than on the highway.

 

[MacLaddy]

What is being discussed in this thread, without being named, is a Peltier device: http://en.wikipedia.org/wiki/Thermoelectric_effect

Thank you, Russ_Watters. I have been trying to figure out a correct search term for some time now.

 

[T.O.E Dream]

What about the heat from a refrigerator? If you ever feel the back of a refrigerator it's really hot, because of the compressor. Can that heat be used to heat the home?

 

[T.O.E Dream]

Is the back of the fridge hot enough to heat the room in it? That is if there is a way we can heat it?

 

[mgb_phys]

Yes - if you want to heat the room even more, open the fridge door

 

[xxChrisxx]

^counter intuative, but true^

I find central heating works rather more effecively though :P

We have one of those new fangled energy efficient fridges, the back doesn't even get noticbly warm (well at least compared to my old one)

 

[T.O.E Dream]

Yes - if you want to heat the room even more, open the fridge door

I hope you're joking.

 

[T.O.E Dream]

Can using the heat generated at the back of the fridge be effective. I mean if everyone turning off the tap while brushing their teeth have an impact on the environment, why can't using the heat generated 24/7 at the back of the refrigerator be effective?

 

[xxChrisxx]

Nope no joke, the fridge will then work harder to try to cool the entire room, effictively turning the fridge into a heat pump.

The point is all this is chasing stupidly small gains. A good fridge now will be using no more than 300KWh per year. A fridge freezer maybe 500KWh. They both have fairly high COP.

They aren't putting out that much waste to begin with.

 

[mgb_phys]

If you need to heat the room then yes it's efficient, or at least exactly as efficient as an electric heater. The problem is what happens when you don't need the heat?
You need to use much more power in the AC to remove this extra heat.

 

[T.O.E Dream]

We keep it how it is now (heat is made whenever it's on) except we're using the heat in the winter.

 

[Lsos]

Can using the heat generated at the back of the fridge be effective. I mean if everyone turning off the tap while brushing their teeth have an impact on the environment, why can't using the heat generated 24/7 at the back of the refrigerator be effective?

You don't have to do anything in order to use a fridge to heat your house. It's going to heat your house whether you like it to or not. It might be all right in the winter, but it's not so good in the summer. If anything, you'd want to look for ways to get rid of that heat, by dumping it outside.

In fact, look at the power consumprion of ANY electrical divide in your house. Your tv, light bulb, computer, calculator, microwave, etc. Ultimately, close to 100% of its power will end up heating your house, again, whether you like it or not, and again this is not necessarily a good thing.

Especially when there's more efficient ways of heating houses. Traditional heaters can only approach 100% efficienty, where as a heat pump, for example, can heat a house by a few hundred percent more than the energy it uses.