What is capacity control of compressor?
What is capacity control of compressor?
Compressor capacity-control methods are utilized to maintain a required compressed gas delivery under variable process conditions. The main capacity control methods for reciprocating compressors are variable-speed drives, suction valve unloaders, step-less methods, clearance pockets and bypass recycling.
Why is refrigeration compressor capacity control needed?
Capacity control or regulation in refrigeration compressors enables the refrigeration plant to run at part loads according to the demand of the refrigerant in the system.
What is compressor capacity in refrigeration system?
The refrigeration capacity of a compressor is the product of the evaporator enthalpy rise and the compressor mass flow rate. Table 3 shows the inlet volumetric flow rates required to achieve 350 ton of cooling.
What determines compressor capacity?
Theoretical capacity of compressor is defined by geometric measurement of air in the working area during one suction period. Then this volume is multiplied by the number of periods (cycles) per time unit.
What factors affect compressor capacity?
Number of cylinders in the compressor;
How is capacity control achieved?
Capacity control can be achieved in several ways with a reciprocating gas compressor. In the following discussion a distinction will be made between methods that are efficient (reduced power with concurrent reduced mass flow so that the power per unit gas is held constant) and those that are not.
Which of the following methods are used to control the capacity of a centrifugal compressor?
Centrifugal compressor capacities can be controlled by causing the compressor to move back on its characteristic curve. This is generally accomplished by throttling the discharge valve. Speed control and external recycle are also common control methods for centrifugal compressors.
Which method is used for capacity control of centrifugal compressor?
A centrifugal compressor’s flow and pressure are typically controlled by a combination of an inlet control device and unloading valve (UV). The inlet can be throttled on a dynamic compressor to continuously reduce the capacity of the compressor.
How is refrigeration capacity calculated?
Divide Q (BTUs per hour) by 12,000 (the number of BTUs in one ton of cooling capacity). This yields the chiller capacity required to handle the process heat load in tons per hour: Example: 240,000/12,000= 20 tons/hr.
How is receiver capacity calculated?
Receiver Tank Calculations
- Receiver tank capacity formula (Equation 1)
- V = T * (C – Cap) * (Pa) / (P1-P2)
- V – Volume of receiver tank (cubic feet)
- T – Time interval (minutes)
- C – Air requirement of demand (cubic feet per minute)
- Cap – Compressor capacity (cubic feet per minute)
- Pa – Absolute atmospheric pressure (PSIA)
What is capacity control in refrigeration compressors?
Capacity control or regulation in refrigeration compressors enables the refrigeration plant to run at part loads according to the demand of the refrigerant in the system. Capacity control is obtained when the solenoid valve, fitted in the top cover, closes the access to the two cylinders, positioned under the same top cover.
How to control the capacity of a reciprocating compressor?
Capacity control compressor. General methods of control power on reciprocating compressors compressor cylinder unloading and motor speed control. For compressors 10 tons and under, the compressor is used most frequently, but the control of the motor speed is increasing in popularity.
Can the capacity of a vapor-compression refrigeration system be controlled?
To read the full-text of this research, you can request a copy directly from the authors. The capacity control of a vapor-compression refrigeration system is investigated for three different capacity control schemes.
What are the different methods of gas compressor capacity control?
One of the most frequently used methods of gas compressor capacity control is direct control of compressor operating speed. Direct compressor speed control can be used with both electric drive and gas engine drive compressors.
