What is Concentrated Solar Power?

A concentrated solar thermal central receiver system uses an optical system to gather solar radiation energy t, and is used to heat a working medium. It is on a large area and is equipped with many large reflectors, usually called heliostats. Each one is equipped with a tracking system to accurately reflect the sunlight reflection on the top of a high tower. The receiver can be more than 100 times light-gathering on the receiver, which is also called a tower solar receiver.

As clean energy, the contribution of solar thermal power plants to the environment is worthwhile

Centralized solar thermal power generation system is also called tower solar thermal power generation system. It builds a tall central absorption tower on the open ground. An absorber is fixed on the top of the tower. A certain number of heliostats are installed around the tower. The heliostats collect sunlight to the receiver on the top of the tower. High temperature is generated in the cavity, and then the working medium passing through the absorber is heated to generate high-temperature steam, which pushes the steam turbine to generate electricity. That is, the tower solar thermal power generation system uses a number of planar reflection arrays to reflect solar radiation to a solar receiver placed on the top of a high tower. The heating working medium generates superheated steam and drives a steam turbine generator set to generate electricity, thereby converting solar energy into electricity. . Obviously, the greater the number of planar mirrors in the array, the greater the light-concentration ratio and the higher the heat collection temperature of the receiver ^[2]

The entire system is composed of 4 parts: concentrating device, heat collecting device, heat storage device and steam turbine power generation device, mainly including heliostat array, high tower, heat absorber, heat transfer medium, heat exchanger, heat storage system, Control system and steam turbine generator set.

In a centralized solar thermal power generation system, the heat absorber is located on a high tower, and the heliostat group is centered on the high tower, and is distributed in a circle. The sunlight is focused on the heat absorber and the heat transfer medium in the heat absorber is concentratedly heated. When the temperature of the medium rises, it is stored in a high-temperature heat storage tank, and then pumped into a steam generator to heat the water to generate steam, and the steam is used to drive the steam turbine unit to generate electricity. The exhaust steam of the steam turbine is condensed by a condenser and sent to a steam generator for recycling. The heat transfer medium that releases heat in the steam generator is returned to the low-temperature heat storage tank, and then sent back to the heat sink for heating.

The heliostat is mainly composed of a flat mirror and a tracking mechanism. The mirror can be made of glass, silver-plated on the back and coated with a protective layer, or it can be made of reflective aluminum plate. The mirror is mounted on the mirror bracket.

The large heliostat has an area of more than 100 square meters and is composed of multiple flat mirrors. For the multiple mirrors on the oversized heliostat, it can be placed in a parabolic shape, which is convenient for concentrating sunlight.

The area of the heliostat is small compared to the heliostat field, and it is far away from the receiver. To accurately reflect the sunlight to the receiver, it must be accurately tracked and positioned. The heliostat generally uses a dual-axis tracking structure, and the control method uses sensors. Tracking and day-to-day tracking are used together. Each heliostat has an independent tracking system, so there is no need for centralized control ^[3] .