Thermodynamic cycle of a solar cell

In summary, the conversation discusses the description of a solar cell in terms of thermodynamics. The model used is a simple loop of heat and work exchange, neglecting kinetic energy, potential energy, and changes in altitude. However, the actual cell has activity going on inside, with materials having holes for electrons to pass through and electrons being moved by photons passing through the crystal structure. The understanding is that friction is neglected, but heat loss comes from this and from the loss of energy when the band gap cannot receive excess eV delivered by photons. The first law of thermodynamics is modeled as Qin - W - Qout = 0, where W represents the work of charging a battery. The speaker notes that their understanding may not be precise
  • #1
whitejac
169
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Mechanical Engineering Undergrad here:
So this didn't seem explicitly like a homework question, but I was wondering how to describe a solar cell in terms of thermodynamics. If I had to model it with the first law of thermodynamics, I would consider it a simple loop of heat/work exchange, idealizing the model to neglect kinetic energy, potential energy, and change in altitude. That just seems a little bit simplistic for me because the actual cell has activity going onto inside of it.

The materials within the cell have holes for electrons to pass through. The electrons move when photons pass through the crystal-structure of the cell. This is the current and friction is neglected here, but that's also where some of the heat-loss comes from (I believe) and then loss of energy when the band gap(?) can't receive excess eV delivered by the photons. So a 3eV ray would lose 1.6eV in a 1.4eV system.

So I would model my first law as such:
Qin - W - Qout = 0
Where W = the work of charging a battery.

Does my understanding sound precise? I'm asking here because I can't afford journals and it seems like my search results in either solar cell distributors (bias info) or academic journals (too technical and costs money).
 
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  • #2
Here is a presentation on photovoltaics from West Virginia Univ, that you may find helpful. https://web.statler.wvu.edu/~wu/mae493/3-solar-3.pdf
 

FAQ: Thermodynamic cycle of a solar cell

1. What is a thermodynamic cycle of a solar cell?

A thermodynamic cycle of a solar cell is a series of energy conversions that occur within a solar cell to produce electricity. It involves the absorption of sunlight, conversion of light energy to electrical energy, and release of waste heat.

2. How does a solar cell convert sunlight into electricity?

A solar cell contains layers of semiconductor materials, typically silicon, which have different levels of positive and negative charges. When sunlight strikes the cell, it creates an electric field between these layers, causing electrons to flow and generate electricity.

3. What is the efficiency of a thermodynamic cycle in a solar cell?

The efficiency of a thermodynamic cycle in a solar cell is the ratio of the electrical energy output to the total energy input from sunlight. The efficiency of most commercial solar cells ranges from 15-20%, but research is being done to improve this efficiency.

4. What happens to the waste heat generated in a solar cell?

The waste heat generated in a solar cell is typically dissipated through the back of the cell or used for other purposes such as heating water. This helps to improve the overall energy efficiency of the solar cell.

5. How does the thermodynamic cycle of a solar cell compare to other energy sources?

The thermodynamic cycle of a solar cell is a sustainable and renewable energy source, unlike fossil fuels which are finite and contribute to environmental pollution. While it may have a lower efficiency compared to some traditional energy sources, advancements in technology and decreasing costs make solar energy an attractive option for a greener future.

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