There are many types of solar thermal systems, but a Parabolic Dish System is the most efficient. It uses a reflective dish to concentrate sunlight onto a receiver, which then converts the sunlight into thermal energy.
This thermal energy can then be used to generate electricity or heat water or air.
What is a Parabolic Dish System?
Parabolic dish systems employ mirrors that are mounted over a parabolic-shaped dish to direct the sun’s rays into a receiver.
The latter is placed at the focal point of the dish, as well as a heat engine (Stirling or Brayton cycle engine), which has thin tubes inside it.
The temperature of the receiver causes the working fluid within the engine’s tubes to expand, forcing it to drive the device.
The parabolic dish is mounted on a tracking device that keeps it pointing at the sun as it moves across the sky.
This ensures that the sunlight is always focused on the receiver. The tracking device can be either manual or automatic.
Parabolic dishes can be used to generate electricity or heat water or air. In order to generate electricity, the heat engine is connected to an electrical generator.
When used for heating water or air, the heat engine is connected to a water pump or fan respectively.
Related: How Do Solar Panels Work?
How does a Parabolic Dish System work?
The Linear Concentrator System is made up of a few key components:
- A parabolic dish that is used to focus sunlight onto a receiver
- A receiver that is placed at the focal point of the dish
- A heat engine (Stirling or Brayton cycle engine) that has thin tubes inside it
- A tracking device that keeps the dish pointing at the sun as it moves across the sky
Advantages of Parabolic Dish System
There are many advantages to using Parabolic Dish System, including:
- Able to track the sun: The tracking device ensures that the dish is always pointing at the sun, no matter where it is in the sky. This means that more sunlight can be focused on the receiver, making the system more efficient.
- Increased Efficiency: Parabolic Dish System is more efficient than other types of solar thermal systems because it uses a reflective dish to concentrate sunlight onto a receiver. This means that more sunlight is used to generate electricity or heat water or air.
Disadvantages of Parabolic Dish System
There are also some disadvantages to using Parabolic Dish System, including:
- A smaller angle of view: This means they require some form of tracking system or manual adjustment to keep them at the correct focal point. Also, parabolic trough reflectors can not collect most of the diffused solar radiation.
- Low conversion efficiency: The conversion efficiency of parabolic dish systems is decreased when compared to other solar thermal technologies, owing to the requirement for a supplementary fuel source used primarily to prevent the heat transfer fluid from freezing and minimal amounts of water required for cooling.
- Fragile: The system is composed of a large number of fragile parts that are susceptible to damage from high winds, hail, and other severe weather conditions.
- High cost: Parabolic dish systems are more expensive than other types of solar thermal systems because they require a tracking device to keep the dish pointing at the sun. This means that more money must be spent on initial installation and maintenance costs.
What Is The Efficiency Of Parabolic Dish?
Parabolic dish concentrators are the most efficient of all solar collector types in CSP technologies.
This is down to the fact that they have a mix of dual-axis tracking and high concentration ratios. The optical efficiencies for various dish concentrators range from 78% to 89%.