Solar Cell Efficiency and Working Principle

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Questions and Answers

What is converted into heat instead of electrical energy in a solar cell?

Short-circuit current

Excess energy generated (correct)

Absorbed radiation energy

Open-circuit voltage

Which charge carriers migrate from the negative to positive side in the space charge region of a solar cell?

Neutrons

Protons

Holes (correct)

Electrons

What cross-sectional area should the cable between the module and the battery have to ensure voltage loss does not exceed 3% for a 12-volt system?

0.17 mm2

1.5 mm2

0.2 mm2

0.35 mm2 (correct)

How is the efficiency of a solar cell calculated?

By dividing the electric power by the total incident radiation intensity Signup and view all the answers

What are the applications of solar photovoltaic systems listed in the text?

Lighting for farm houses, farm-to-market road, crop irrigation, and poultry incubators and hatchers Signup and view all the answers

What happens to the open-circuit voltage of a solar cell as the temperature increases at constant radiation intensity?

It decreases Signup and view all the answers

If a solar-powered pump requires 15 hp with a safety factor of 1.6, what is the total power required for the system?

23.4 kW Signup and view all the answers

How many strings are needed to deliver the power required by the 800-volt inverter?

4 strings Signup and view all the answers

How many modules are required for the solar-powered pump with module specifications of Wp – 310 watts, Isc – 8.84 Amp, Voc – 45.7 volts?

8 modules Signup and view all the answers

Which material has the highest theoretical efficiency among the options given for solar cell materials?

GaAs Signup and view all the answers

If a solar array needs to deliver power to a pump using an 800-volt inverter, how many modules per string are required for the array?

30 modules per string Signup and view all the answers

Which of the following statements about the influence of radiation intensity on a solar cell is true?

The power output increases directly proportional to radiation intensity Signup and view all the answers

What is the typical rating of solar radiation on a sunny day?

1 kW/m² Signup and view all the answers

What is a solar battery rated in terms of?

Ampere-hour Signup and view all the answers

Which of these devices generates electricity from sunlight?

Photovoltaic Signup and view all the answers

What is the ampere-hour capacity of the battery needed for a 12V, 73.6 Wh solar panel system?

6.13 Ah Signup and view all the answers

Which component of a solar electric system converts sunlight to electricity?

All of the above Signup and view all the answers

Which factor affects solar radiation?

All of the above Signup and view all the answers

What is the main advantage of using a solar cell module at low radiation intensity levels?

It can utilize the power output more efficiently. Signup and view all the answers

What is the approximate weight of a solar cell module with 36 solar cells?

4 kg Signup and view all the answers

What is the purpose of a charge regulator in a photovoltaic system?

To regulate the charging of the battery from the solar module. Signup and view all the answers

What type of solar module material has the best efficiency in utilizing sunlight?

Mono Crystalline Silicon Signup and view all the answers

If a solar-operated pump requires 74 volts, and each panel has a rating of 12 volts, how many panels are needed in series connection?

6 panels Signup and view all the answers

What is the significance of the glass cover in a solar module?

It protects the solar cells from environmental factors. Signup and view all the answers

What is one of the key steps mentioned to estimate the total load for a PV system?

Computing the total load and normalizing the load profile Signup and view all the answers

Why is it important to select the appropriate array tilt for a PV system?

To optimize solar radiation capture at the proposed site Signup and view all the answers

In estimating the array size in peak ampere, what formula is used in the provided text?

Array Size = Sum of Electrical Load for 2 worst months / Sum of Insolation for the same months Signup and view all the answers

Why is it necessary to compute the battery storage requirement for a PV system?

To account for monthly deficit amounts Signup and view all the answers

Which step involves selecting two adjacent months with the highest load-to-insolation ratio?

Estimating the array size in peak ampere Signup and view all the answers

What is assumed when computing the total load and normalizing the load profile for a PV system?

Assume 90% current efficiency for the battery Signup and view all the answers

Study Notes

Solar Cells and Photovoltaic Systems

Solar cells convert sunlight into electrical energy through the separation of charge carriers (holes and electrons) in the presence of an electric field.
The efficiency of a solar cell is determined by dividing the electric power output by the total incident radiation intensity.
Theoretical and experimental efficiencies of various solar cell materials are:
- Si (mono crystalline): 22% (theoretical), 16% (experimental)
- Cu2CdS: 18% (theoretical), 7% (experimental)
- GaAs: 26% (theoretical), 21% (experimental)
- CdTe: 25% (theoretical), 6% (experimental)

Influence of Operating Temperature and Radiation Intensity

Increasing temperature decreases the open circuit voltage, but has little effect on the short-circuit current.
Power output decreases as temperature increases.
Power output increases with radiation intensity.

Applications of Solar Photovoltaic Systems

Lighting for farm houses, farm-to-market roads, and farm buildings
Crop irrigation (non-pressurized and pressurized systems)
Poultry incubators and hatchers

Solar Panel Systems and Modules

A solar panel system consists of a solar module, battery, charge regulator, lamp, radios, and cables.
Solar modules are arrays of solar cells interconnected and encapsulated behind a glass cover.
The stronger the light on the cells and the larger the cell surface, the more electricity is generated.
Characteristics of a solar cell module:
- Panel dimension: 560mm x 480mm x 13mm
- Weight: 4 kg
- Short circuit current: 1150 mA
- Open circuit voltage: 20.8 V
- Output current and power: 1010 mA and 15.9 W, respectively

Solar Module Materials

Mono Crystalline Silicon: has the best efficiency (14%), but is more expensive than multi-crystalline silicon.

Designing a Solar Photovoltaic System

Steps to design a solar photovoltaic system:
1. Estimate the average daytime and night time current requirements.
2. Compute the total load and normalize the load profile.
3. Select the appropriate array tilt based on the location of the proposed PV site.
4. Determine the insolation for the location and tilt angle.
5. Compute the load-to-insolation ratio for each month.
6. Estimate the array size in peak ampere for the two worst conditions.
7. Compute the battery storage requirement.

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Description

Learn about the operational principle of a solar cell and how electric fields cause charge carriers to move, generating voltage and electric current. Explore the efficiency of solar cells and how excess energy is dissipated as heat. Test your knowledge on solar cell functionality!