In this article, we’ll explore the key differences between On-Off compressors and VCC (Variable Capacity Compressors) used in single-phase refrigerators. Understanding these differences is essential for any refrigeration technician.
1. Capacity and Control
- On-Off Compressor:
Its capacity is fixed and controlled through on-and-off cycles. Cooling capacity, efficiency, and refrigerant mass flow depend on the condensation temperature and evaporation pressure. - VCC Compressor:
Adjusts its capacity based on sensor readings and control by an electronic board. This makes it more efficient but initially more expensive.
2. Rotational Speed (RPM)
- On-Off Compressor:
Maintains a constant speed, operating at the same compression ratio until the desired temperature is reached. - VCC Compressor:
Operates at variable speeds. It increases RPM when more cooling is needed and decreases RPM when demand is lower, allowing adjustable compression.
3. Power Consumption
- On-Off Compressor:
Operates with nearly constant electrical current, leading to higher energy consumption. - VCC Compressor:
Consumes less power by adjusting energy use according to RPM, reducing operational costs.
4. Vibration and Noise
- On-Off Compressor:
Produces more vibration and noise due to frequent start-stop cycles. - VCC Compressor:
Quieter operation thanks to continuous and adjustable functioning.
5. Temperature Stability
- On-Off Compressor:
Temperature fluctuates due to on-and-off cycles. - VCC Compressor:
Maintains more stable temperatures by varying RPM.
6. Cooling Speed
- On-Off Compressor:
Slower cooling due to fixed operation. - VCC Compressor:
Provides faster cooling by adjusting RPM to meet demand.
7. Electrical Connection
- On-Off Compressor:
Connects directly to the power line and requires starting kits like relays or capacitors. - VCC Compressor:
Powered through an inverter board and doesn’t need starting kits.
8. Coils
- On-Off Compressor:
Has two coils: one for start-up and another for operation, with different resistances. - VCC Compressor:
Three-phase with three coils of equal resistance, powered by the inverter board.
