Parabolic trough collector. A set of parabolicmirrors can be used to concentrate the sun's rays to heat a fluidflowing in a pipe positioned at the mirrors' focal points. Theheated fluid, such as oil, for example, is transported to apressurized tank to be used to create steam to generate electricityor power an industrial process. Since the solar energy varies withtime of day, time of year, cloudiness, humidity, etc., a controlsystem has to be developed in order to maintain the fluidtemperature constant. The temperature is mainly controlled byvarying the amount of fluid flow through the pipes, but possiblyalso with a solar tracking mechanism that tilts the mirrors atappropriate angles.
Assuming fixed mirror angles, draw the functional block diagramof a system to maintain the fluid temperature a constant. Thedesired and actual fluid temperature difference is fed to acontroller followed by an amplifier and signal conditioning circuitthat varies the speed of a fluid circulating pump. Label the blocksand links of your diagram, indicating all the inputs to the system,including external disturbances such as solar variations,cloudiness, humidity, etc.