Gemini on Question 7, Sep 15

A refrigerator works by removing heat from its interior and releasing it into the room outside, rather than by actually creating cold air. This process relies on a continuous cycle of a chemical substance called a refrigerant, which changes between a liquid and a gas as it moves through a closed system of tubes. The fundamental principle driving this mechanism is that when a liquid turns into a gas, it absorbs heat from its surroundings, and when a gas condenses back into a liquid, it releases that heat.

The cooling cycle begins at the compressor, a motorized pump usually located at the bottom of the appliance. The compressor takes in low-pressure refrigerant gas and squeezes it tightly. This intense compression causes the gas to become extremely hot and highly pressurized. The hot gas is then pushed out into the condenser coils, which are typically found on the back or underneath the refrigerator. As the hot gas travels through these exterior coils, it releases its heat into the surrounding air of the kitchen. Losing this thermal energy causes the high-pressure gas to condense into a high-pressure liquid.

Next, this high-pressure liquid travels toward the interior of the refrigerator and is forced through a very narrow opening known as an expansion valve or capillary tube. Pushing through this tiny space causes the liquid to experience a sudden and dramatic drop in pressure. This rapid depressurization forces the liquid to expand and cool down drastically, similar to how an aerosol can feels cold after you spray it.

The freezing-cold liquid then flows into the evaporator coils located inside the main refrigerator cabinet. As the cold refrigerant moves through these interior tubes, it absorbs the heat radiating from the food and air inside the fridge. A small fan blows air over these cold coils to circulate the chilled air evenly throughout the interior compartment. Meanwhile, absorbing the heat causes the cold liquid refrigerant inside the coils to boil and evaporate, turning back into a low-pressure gas. This newly formed gas is then sucked back down into the compressor, and the entire cycle begins all over again to keep your food continuously cold.