Stirling engine against solar panels

In summary, the conversation discusses the possibility of creating miniature electric motors using a dark material to convert solar energy into electricity. The efficiency of such converters is heavily influenced by the design and materials used, with current solar panels only achieving an efficiency of 20%. The conversation also brings up the idea of replacing solar panels with small converters, but it is pointed out that the efficiency would be much lower due to the temperature difference between the hot and cold reservoirs. The conversation also mentions the calculation of thermodynamic efficiency for heat engines like Stirling engines.
  • #1
Jarro
2
0
Hello,
Since childhood, I have been wondering why it is not possible to make miniature electric motors with pistons and gas container covered with a very dark (meaning high absorption coefficient over a wide spectral width) material that would translate the energy of sunlight directly into electricity? In fact, only material and design features will significantly affect the converter efficiency when, as in the case of solar panels, expensive and complex photocells output η of only ~20%. I know that such engines are used on large solar parks (multiple mirrors concentrate solar energy at one point), but why not to simply replace each square meter of each solar panel (meaning literally everywhere it is used) with a such small converter? What did I miss in the concept?
P.S. English isn't my native language, sorry
 
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  • #2
Do you understand how to calculate the thermodynamic efficiency of a heat engine like a Stirling engine? It is dependent on the temperature difference between the hot reservoir and the cold reservoir. The best solar thermal generators, which (as you said) use concentrating mirror arrays to achieve high temperatures, only achieve an efficiency of about 30%. If you used small engines like you suggest, the temperature achieved would be much lower and the efficiency would be much less.
 
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Likes Jarro
  • #3
phyzguy said:
It is dependent on the temperature difference between the hot reservoir and the cold reservoir.
Oh those are the basics I did not pay attention to, thanks.
 

FAQ: Stirling engine against solar panels

1. What is a Stirling engine and how does it work?

A Stirling engine is a type of heat engine that operates by cyclic compression and expansion of air or other gas at different temperatures, resulting in a net conversion of heat energy into mechanical work. It works by using a closed cylinder filled with a gas, such as air, and two pistons. One piston is heated, causing the gas to expand and push the other piston, which then compresses the gas. This process is repeated, resulting in a continuous cycle of expansion and compression, which drives the engine's motion.

2. How is a Stirling engine different from other types of engines?

A Stirling engine is different from other types of engines, such as internal combustion engines, in that it does not use fuel combustion to generate power. Instead, it relies on heat energy from an external source, such as the sun, to power the engine. This makes it a more environmentally friendly option, as it does not produce harmful emissions.

3. Can a Stirling engine be used in conjunction with solar panels?

Yes, a Stirling engine can be used in conjunction with solar panels. The engine can be connected to the solar panels, which will provide the heat energy needed to power the engine. This makes it a possible alternative to traditional solar panels, as it can generate electricity even when the sun is not shining, as long as there is a sufficient temperature difference between the hot and cold sides of the engine.

4. What are the advantages of using a Stirling engine against solar panels?

There are several advantages to using a Stirling engine against solar panels. One of the main advantages is its ability to generate electricity even when the sun is not shining, as long as there is a temperature difference between the hot and cold sides of the engine. This makes it a more reliable source of renewable energy. Additionally, Stirling engines have a longer lifespan and require less maintenance compared to other types of engines.

5. Are there any limitations to using a Stirling engine against solar panels?

While a Stirling engine has many advantages, there are also some limitations to consider. One limitation is that it is not as efficient as other types of engines, such as internal combustion engines. This means that it may not be able to generate as much power as other options. Additionally, the initial cost of a Stirling engine may be higher compared to traditional solar panels. However, the longer lifespan and lower maintenance costs may make up for this in the long run.

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