The function and structure of the refrigerator evaporator

I. Function
The role of the evaporator in the refrigerator cooling system is “absorbing heat”. Specifically:
1. Absorbing heat to achieve cooling: This is its core mission. The liquid refrigerant evaporates (boils) inside the evaporator, absorbing a large amount of heat from the air inside the refrigerator and the food, thereby lowering the temperature inside the box.
2. Dehumidification: When hot air comes into contact with the cold evaporator coils, the water vapor in the air will condense into frost or water, thereby reducing the humidity inside the refrigerator and achieving a certain dehumidification effect.
A simple analogy: The evaporator is like an “ice cube” placed inside the refrigerator. It continuously absorbs heat from the surrounding environment, melts (evaporates) itself, and thereby makes the environment cooler.
II. Structure
The structure of the evaporator varies depending on the type of refrigerator (direct cooling vs. air-cooling) and cost, and mainly includes the following types:
1. Plate-fin type
Structure: Copper or aluminum tubes are coiled into an S-shape and then adhered or embedded onto a metal plate (usually an aluminum plate).
Features: Simple structure, low cost. It is mainly used in the refrigeration and freezing compartments of direct-cooling refrigerators, and is usually directly used as the inner liner of the freezing compartment.
Appearance: In the freezing compartment, the circular tubes you see on the inner wall are it.
2. Finned coil type
Structure: Copper or aluminum tubes pass through a series of closely arranged aluminum fins, forming a structure similar to an air heater or an automotive radiator.
Features: Very large heat (heat absorption) area, high efficiency. It is mainly used in air-cooling (non-frosting) refrigerators. Usually, a fan is also provided to force the air inside the box to flow through the gap between the fins for heat exchange.
Appearance: Usually hidden inside the air duct, and cannot be seen directly from the inside of the refrigerator.
3. Tube type
Structure: The coil is welded onto a dense wire mesh frame.
Features: High strength, good corrosion resistance. It is commonly used as the evaporator for commercial refrigerators and can also be found in some old or economy-type refrigerators in the freezing compartment.