Energy Concept

[belovelife]

ok , i bought a cup that changes color when it gets filled with hot liquid

 

mainly coffee and tea

 

anyway

after pndering it for a while

 

( like i used to ponder color changing clothes )

 

i wondered if this concept could help with the efficiencies of steam power plants

 

where you surrounding the area that gets hot with a solar type pannel that transduces infrared light in to energy

 

 

 

is this possible?

[CraigD]

ok , i bought a cup that changes color when it gets filled with hot liquid

…

i wondered if this concept could help with the efficiencies of steam power plants

 

where you surrounding the area that gets hot with a solar type pannel that transduces infrared light in to energy

Ignoring the practical difficulty of making a photoelectric material that converts heat radiation to electricity, keep in mind that, in steam powerplants, photoelectric panels, or any other physical system that doesn’t involve nuclear or other mass-reducing reactions, energy is conserved.

 

If you extract heat from the steam on the pre-turbine or piston side of a steam engine, the energy available to the engine is reduced. If you extract it from the exhaust side of an open-ended steam engine, less heat is available to pre-heat the cold input water, so energy to the engine is again reduced.

 

Only if the heat-extracting system is more efficient than the engine would it improve the efficiency of the total system. But it this were the case, it would be even more efficient if the engine were eliminated altogether.

[belovelife]

right, but we have infrared goggles,

 

if we put a nano layer of these amterials on a sheet , or other surface, than all the ecce3ss heat radiated off the engine would be converted into energy, therefore, not reducing the

 

potential work that the steam does to spin the turbine,

[Guest MacPhee]

Ignoring the practical difficulty of making a photoelectric material that converts heat radiation to electricity, keep in mind that, in steam powerplants, photoelectric panels, or any other physical system that doesn’t involve nuclear or other mass-reducing reactions, energy is conserved.

 

If you extract heat from the steam on the pre-turbine or piston side of a steam engine, the energy available to the engine is reduced. If you extract it from the exhaust side of an open-ended steam engine, less heat is available to pre-heat the cold input water, so energy to the engine is again reduced.

 

Only if the heat-extracting system is more efficient than the engine would it improve the efficiency of the total system. But it this were the case, it would be even more efficient if the engine were eliminated altogether.

 

It seems to me, that the question is not about "extracting heat" from the inner mechanism of the steam engine, ie its pistons and cylinders.

 

Rather about making use of the excess, or waste, heat from the engine. In an ordinary steam engine, doesn't this waste heat just get radiated away into the air? So the air around the engine gets heated up a bit. But the heated air then just moves away in air currents, which quickly dissipate the energy into the random movements of the atmosphere - without having done any useful work. The energy is wasted.

 

But this wastage could be reduced, if the engine were surrounded by some kind of "energy-capturing" devices. Perhaps infra-red sensistive panels, like belovelife suggested. These would capture the waste heat, and make it do useful work.

 

Such external devices couldn't interfere with the inner workings of the steam engine, or make it work less efficiently surely? They'd be pure gain.

Edited July 21, 2012 by MacPhee

[CraigD]

It seems to me, that the question is not about "extracting heat" from the inner mechanism of the steam engine, ie its pistons and cylinders.

 

Rather about making use of the excess, or waste, heat from the engine.

 

But this wastage could be reduced, if the engine were surrounded by some kind of "energy-capturing" devices.

You’re correct, MacPhee – waste heat from engines, steam and other kinds, wastes the energy of the fuels expended to power them.

 

With heat engines, a common solution is not to add a different kind of system to utilize this heat, but to insulate the system to prevent its escape, increasing the energy utilized by the main engine.

 

Keep in mind that “peripheral” heat loss is almost always less than heat lost in the exhaust of heat engines – CO₂-rich gas, and in open-cycle steam or hydrogen-burning engines, hot steam. A common solution to pipe these hot gasses to the engine’s intake, allowing less fuel to be consumed to feed it the same amount of heat energy.

 

A major barrier to both these approaches is that many engine materials – commonly alloys of iron – soften and melt at temperatures produced by their burning fuels. One response is to build engines using higher temperature materials, such as ceramics. This approach has, to the best of my knowledge, gotten little beyond the experimental stage, mostly due to higher temperature materials being less durable than those they replace. There are exceptions to this rule, such as titanium metal, but they’re significantly more expensive than steel or ceramic.

 

The engineering tradeoffs involved here are, as with most things in our money-driven society,

Often cost-driven. One could better insulate and transfer exhaust heat in a given engine to make it more fuel efficient, but at the cost of the same engine producing less power, or an engine producing the same power (while using less fuel) being larger and more expensive to build.

 

Another tradeoff is power vs. weight. A more efficient engine typically is large and heavier than a less efficient one, so not as suitable for use in vehicles. Keep in mind, by energy consumption, about half of all engine are in small vehicles, vs. half in large ones or fixed power plants.

 

Perhaps infra-red sensistive panels, like belovelife suggested. These would capture the waste heat, and make it do useful work.

There’s a basic physics issues here – not a showstopper, one might even say a semantic technicality.

 

The elements in photoelectric materials – ones that can convert electromagnetic radiation (photons) into electric current (electrons) – all have a minimum per-photon energy below which they won’t produce any current. This is known as their work function, and for all usable elements, are fairly similar, in the range of 2 to 6 eV. Doing the math (via [math]E=\frac{hc}{\lambda}[/math]), this equates to wavelengths of about 620 nm (6.2x10^-7 meters) to 200 nm. Visible light in in the range 740 to 380, so we can see that photoelectric materials work only up to wavelengths in the visible range, and the shorter ultraviolet range, stopping well short of the infrared band.

 

In short, photoelectric panels don’t work for heat photons, only visible light and more energetic ones. To generate electricity from a stream of infrared photons (or, as is significant in an atmosphere, heat transferred by convention and conduction) you need either a heat engine capable of operating at a lower temperature difference (such a Sterling engine) connected to an electric generator, or a thermoelectric generator (such as a Seebeck device, a solid-state device).

 

There’s certainly a niche for such technology, because it can potentially simplify and reduce the cost of systems where the main heat engine isn’t used to generate electricity, but the system needs a small amount of electricity for control or accessory systems, designers wish to avoid the additional bulk, weight, and cost of a motor-driven electric generator, or high efficiency justifies additional cost. The main problem with the technology is that, compared to conventional heat engines of the same size and weight, they’re lower power and more expensive.

 

Such technology has been experimented with since the early 1960s, primarily applied to gas and diesel piston engine powered cars and trucks (“automotive thermoelectric generator”), but, like the high temperature engine materials that would allow more efficient utilization of exhaust heat and eliminate wasteful engine cooling needs, have remained to the best of my knowledge experimental, without production application.

 

Such external devices couldn't interfere with the inner workings of the steam engine, or make it work less efficiently surely? They'd be pure gain.

If they replace insulation (as any sort of heat engine, mechanical or solid state, must do, since they depends on having a hot and cold side), they will reduce – essentially “steal” energy from the main heat engine.

 

If they don’t, they are pure gain, their only downside being bulk, and weight, and cost.

[belovelife]

i was thinking nano-layered photovotallic, with a filter on the top layer that doubles the wavelenght

is that possible?