This is Josh. Josh put a sandwitch in the refridgerator to eat for later but how does this device work?
As Liquid Evaporates - Energy(heat) is absorbed
To first understand how refridgerators function, we will first have to state the relationship liquids have with heat
As Liquid Condenses - Energy (heat) is released
A Compressor
A thermal expansion device
Refridgerators are composed of 4 main components
Evaporator and Condenser Coils
Refrigerant - Typically 1,1,1,2-Tetrafluoethane in modern fridges
Refrigerant is passed through the thermal expansion device through the evaporator coils. Going through the coils, the drop in pressure causes the liquid to expand, and begin evaporating. This causes it to begin absorbing heat within the fridge
Low Pressure cools and refridgerant begins to evaporate
Heat from Items inside the fridge are absorbed
Hot refridgerant cools
Inside the compressor, the liquid experiences high pressure making the refridgerant extremely hot. As it leaves the pump, it is already in a vapor state. As the liquid leave through the compressor in the condenser coils, the heat from the refridgerant dissipates into the atmosphere turning it back into a liquid and the now liquid refridgerant is in turn brough back to the thermal expansion valve.
Compressure adds pressure to the refridgerant and releases it through condenser coils
This process repeats itself creating the basis of how a modern refridgerator works. Heat is absorbed through an evaporating liquid, and then afterwards released outside of the refridgerator into the atmosphere. Through this method, Josh can be assured that his sandwitch will be kept cool for as long as he likes.