heliostaten

A heliostat is a device that reflects sunlight from a large area into a smaller, more manageable area. The term "heliostat" is derived from the Greek words "helios," meaning sun, and "stasis," meaning standing still. Heliostats are commonly used in solar power plants to concentrate sunlight onto a receiver, which then converts the solar energy into heat or electricity.

The basic principle behind a heliostat is the reflection of sunlight using mirrors. These mirrors are typically flat and can be adjusted to track the sun's movement across the sky. The reflected sunlight is focused onto a receiver, which is usually located at the top of a tower. The concentrated sunlight heats a fluid, such as water or molten salt, which is then used to generate steam and drive a turbine to produce electricity.

Heliostats are an essential component of concentrated solar power (CSP) systems. They offer several advantages over photovoltaic (PV) systems, including the ability to store energy and provide a more consistent power output. However, heliostats also have some disadvantages, such as their high initial cost and the need for a large amount of land.

Heliostats have been used in solar power plants since the 1980s. The largest heliostat field in the world is located at the Ivanpah Solar Electric Generating System in California, USA. This plant uses over 300,000 heliostats to generate 392 megawatts of electricity.