Gemini on Question 7, Sep 10

A refrigerator works by removing heat from its interior and releasing it into the surrounding room, rather than actually creating cold air. This process relies on a continuous cycle of evaporation and condensation, driven by a chemical substance called a refrigerant that travels through a closed loop of copper tubing. The cycle is powered by a motorized pump called a compressor. The compressor squeezes the gaseous refrigerant, which drastically increases its pressure and temperature. This hot, highly pressurized gas is then pushed into the condenser coils, which are usually located on the outside back or bottom of the appliance. As the hot gas travels through these exterior coils, it releases its heat into the air of your kitchen. Losing this heat causes the pressurized gas to condense into a warm liquid.

This liquid refrigerant is then forced through a very narrow passage known as an expansion valve. When the liquid emerges on the other side of the valve, it enters an area of much lower pressure. This sudden drop in pressure causes the liquid to expand and cool down incredibly rapidly, turning into a freezing cold liquid and vapor mixture. This frigid mixture then flows through the evaporator coils, which are located inside the refrigerator. As the cold refrigerant moves through these interior coils, it absorbs heat from the warm air and food inside the appliance. An internal fan blows air across these cold coils to circulate the newly chilled air throughout the fridge. Because the refrigerant absorbs so much heat from the interior, it boils and evaporates back into a low-pressure gas. This gas is then drawn back into the compressor, and the entire cycle repeats continuously until the internal thermostat senses that the inside of the refrigerator has reached the desired temperature and temporarily shuts the compressor off.