Electric refrigerators

An electric refrigerator uses the evaporation of a liquid to absorb heat. As the liquid evaporates, it absorbs heat and creates the cool feeling. The liquid, or refrigerant, used in a refrigerator evaporates at an extremely low temperature so it can create freezing temperatures inside the refrigerator. The way modern refrigerators work is they use a regenerating cycle to reuse the same refrigerant over and over.

Gas refrigerators

If you own or use a refrigerator where electricity is not available, chances are you have a gas-powered or propane-powered refrigerator. Gas refrigerators are interesting because they have no moving parts and use gas or propane as their primary source of energy. They are also odd because they use heat, in the form of burning propane, to produce the cold inside the refrigerator.

A gas refrigerator uses ammonia as the coolant, and it uses water, ammonia and hydrogen gas to create a continuous cycle for the ammonia.

Categorizing a fridge

Refrigerators are categorized according to the way frost is removed from them.

Standard refrigerator

Defrosts when the power is turned off and the frost is permitted to melt slowly away on its own or with the aid of pans of hot water placed in the freezer.

Cycle-Defrost model

A heater that is turned on when the temperature on the evaporator reaches a preset point, keeps the refrigerator compartment free of frost, but the freezer requires manual defrosting every few months.

Frost-Free refrigerator

Frost from both compartments is continually melted away by a heater that turns on for 20 -30 minutes, two or three times a day. Clearly, this type of refrigerator offers the ultimate in convenience, though it's somewhat more prone to problems and is considered less energy-efficient.

-- Tips courtesy of HomeAdvisor.com