A fridge doesn’t create cold — it removes heat from inside and dumps it outside (usually through the warm coils on the back).
It’s basically a heat‑moving machine.
It works using a repeating cycle:
🔁 The 4‑step refrigeration cycle
1. Compression (the “pump”)
- A compressor squeezes the refrigerant gas.
- This makes it hot (compressed gas heats up).
2. Condensation (the hot coils on the back)
- The hot gas flows through the coils behind the fridge.
- It releases heat into the room and turns into a liquid.
- That’s why the back of the fridge feels warm.
3. Expansion (the magic moment)
- The liquid passes through an expansion valve.
- It suddenly expands → pressure drops → it becomes very cold.
4. Evaporation (cooling inside the fridge)
- The cold refrigerant flows through coils inside the fridge.
- It absorbs heat from your food and the air.
- As it absorbs heat, it evaporates back into a gas.
Then the cycle repeats.
🧊 Why this keeps food cold
Inside the fridge:
- Heat is constantly being pulled out.
- The temperature stays around 0–5°C (32–41°F).
- Bacteria grow slower at low temperatures, so food lasts longer.