Expansion Valves and Driers
- Function of a Drier
- A drier is used in refrigeration and air conditioning systems to:
✅ Remove moisture from the refrigerant.
✅ Prevent ice formation in the expansion valve.
✅ Filter out dust, dirt, and debris to protect the compressor.
- Types of Driers & Applications
| Type | Description | Application |
|---|---|---|
| Liquid Line Drier | Installed in the liquid line to remove moisture and contaminants. | Domestic & commercial refrigeration, air conditioning. |
| Suction Line Drier | Placed in the suction line to prevent moisture from entering the compressor. | Used in large systems like commercial refrigeration. |
| Molecular Sieve Drier | Contains desiccants (zeolite) for high moisture absorption. | Deep freezers, transport refrigeration. |
| Silica Gel Drier | Uses silica gel for efficient drying. | Small domestic refrigerators. |
- Advantages of Using a Drier
- ✔ Protects the expansion valve from moisture-related blockages.
✔ Extends compressor life by preventing damage from contaminants.
✔ Enhances system efficiency and reduces maintenance costs.
- 2. EXPANSION VALVE
- Function of Expansion Valve
- An expansion valve controls the flow of refrigerant from the high-pressure liquid line to the low-pressure evaporator. It:
✅ Reduces refrigerant pressure before entering the evaporator.
✅ Regulates refrigerant flow based on cooling demand.
✅ Ensures efficient heat absorption in the evaporator coil.
- Types of Expansion Valves & Applications
| Type | Description | Application |
|---|---|---|
| Capillary Tube | A simple, fixed-length tube that restricts refrigerant flow. | Domestic refrigerators, deep freezers. |
| Automatic Expansion Valve (AEV) | Maintains a constant pressure in the evaporator. | Small refrigeration systems. |
| Thermostatic Expansion Valve (TXV) | Regulates refrigerant flow based on evaporator temperature. | Air conditioners, commercial refrigerators. |
| Electronic Expansion Valve (EEV) | Uses a sensor and electronic controller for precise control. | Modern HVAC and industrial refrigeration. |
- Expansion Valve in Domestic Refrigeration & Air Conditioning
- Domestic Refrigerators: Use a capillary tube because of its simple, low-cost operation.
- Air Conditioners: Use Thermostatic Expansion Valves (TXV) for better efficiency and temperature control.
- Comparison of Capillary Tube & Expansion Valve
| Feature | Capillary Tube | Expansion Valve |
|---|---|---|
| Control | Fixed refrigerant flow | Adjusts flow based on demand |
| Efficiency | Less efficient | More efficient |
| Cost | Cheap & simple | Expensive but precise |
| Usage | Household refrigerators | ACs & commercial refrigeration |
