Compressor energy conservation

In a V/f control generally, only the frequency is varied to obtain the required speed control. Based on this frequency, the switching logistics of the inverter control circuit control the inverter s output voltage using the PWM technique to maintain the same ratio of V/f. A W/control is, however, not suitable at lower speeds. Their application is limited to fan, pump and compressor-type loads only, where speed regulation need not be accurate, and their low-spccd performance or transient response is not critical and they are also not required to operate at very low speeds. They arc primarily used for soft starts and to conserve energy... 

Control of the compressor is achieved by engaging the required number of cylinders. In. say. a 16-cylinder compressor if we engage only four cylinders, the compressor will run at 25 7r capacity, and if w c engage eight cylinders, the compressor will run at. 5()C< capacity. Electrically operated solenoid valves are provided for capacity control. Energy can be conserved by using static controls, as discussed in Section 6.15. 

The air required for combustion is compressed by rotating piston compressors or turbo blowers. The air is preheated in heat exchangers by hot gases containing carbon black leaving the reactor. This conserves energy and thus improves the carbon black yield. Preheated air temperatures of 500-700 °C are common. 

The design of a compressor begins with the First Law of Thermodynamics, the conservation of energy. The work required to compressed the gas is calculated as follows ... 

A number of rotating components are in common use in process plants, e.g. turbines, compressors, pumps, centrifuges and stirring paddles, and it is important to understand how such pieces of equipment are affected by the conservation of energy. For a rotating component, the principle of conservation of energy states that... 

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