The Electrolux Refrigerator

Electrolux Refrigerator

The Electrolux refrigerator is a classic example of a diffusion–absorption refrigeration system that operates without any moving parts such as a compressor or pump. Developed in the 1920s by Swedish engineers and later commercialized by Electrolux, this refrigerator works using heat energy as the driving force instead of mechanical work.

Because it is silent, reliable, and can run on gas, kerosene, or electricity, the Electrolux (absorption) refrigerator is widely used in hotels, caravans, remote areas, and minibars.

1. Principle of Operation

The system works on the absorption refrigeration principle using three working fluids:

• Ammonia (NH₃) – refrigerant

• Water (H₂O) – absorbent

• Hydrogen (H₂) – inert gas to reduce partial pressure

Cooling is produced by evaporation of ammonia at low partial pressure in the presence of hydrogen.

2. Main Components

1. Generator (boiler)

2. Separator (rectifier)

3. Condenser

4. Evaporator

5. Absorber

6. Gas heat exchanger

No compressor, no pump, no moving parts.

3. Working Cycle

Step 1: Generation

A heat source (electric heater or gas flame) heats the ammonia–water solution in the generator. Ammonia vapor separates from water.

Step 2: Condensation

Ammonia vapor flows to the condenser, rejects heat, and becomes liquid ammonia.

Step 3: Evaporation

Liquid ammonia enters the evaporator where hydrogen gas is present. Hydrogen reduces ammonia’s partial pressure, causing it to evaporate at low temperature and produce cooling.

Step 4: Absorption

Ammonia vapor is absorbed back into water in the absorber, forming strong solution again.

Step 5: Return to Generator

The strong solution flows back to the generator by gravity, and the cycle repeats.

4. Role of Hydrogen Gas

Hydrogen does not react chemically. Its function is to:

• Reduce partial pressure of ammonia

• Enable low-temperature evaporation

• Maintain continuous diffusion process

5. Heat Source Options

• Electrical heater

• LPG / natural gas flame

• Kerosene burner

• Solar heat (in remote designs)

6. Advantages

1. Completely silent operation

2. No moving parts → very low maintenance

3. Can operate without electricity

4. Long service life

5. Reliable in remote locations

7. Limitations

1. Low COP compared to vapour compression systems

2. Slow cooling rate

3. Bulky system

4. Requires careful leveling for proper operation

8. Applications

• Hotel minibars

• Caravans and RVs

• Remote rural refrigeration

• Vaccine storage in off-grid areas

• Laboratory cooling

9. Comparison with Vapour Compression Refrigerator

10. Why It Is Called a Diffusion–Absorption System

Because:

• Refrigerant diffuses in hydrogen gas in evaporator

• Refrigerant is absorbed in water in absorber