In the refrigeration technology, the efficiency of evaporators and condensers heat transferring increases with the help of a fan, and the fastest cooling of products, after loading them into the chamber, is ensured.
In the refrigeration systems, two types of fan are often used:
- evaporator or condenser fan,
- compressor blower fan.
The fan of the evaporator or condenser unit
The fan of the evaporator (of an air cooler in the chamber), and of the condenser must meet the highest standards – to be as reliable as possible, effective and have a low noise level during the operation. This is because it must operate for a long period under various conditions of temperature and humidity without additional maintenance.
Most often, designers use axial-flow fans for the refrigeration equipment. They are attached directly to the evaporator or condenser casing.
For a correct selection of the fan for the refrigeration system, many parameters must be taken into account. Here, the electric motor power, the evaporator capacity, the blades material, and many other things should be correlated. That is why the most evaporators and condensers are delivered with pre-installed fans, selected for the specific technical conditions.
An axial-flow fan is a multi-bladed wheel located in the special casing. Blades are fixed at the special sleeve depending on the given angle to the wheel rotation plane. They have a curved shape that allows them to grasp the air when rotating and guide it parallel to the rotation axis. At a sufficiently low noise level, the axial-flow fan can produce in a predetermined direction a powerful air jet that increases the heat exchange of the air and the evaporator and is sent to the refrigerated chamber. Depending on the rotational speed, the power and range of the airflow can be adjusted. Modern fans are equipped with the thermal control systems that shut down the engine in case of overheating, as well as with the control units of different types that allow changing the rotational frequency.
One of the latest technological trends is the development and production of fans from plastic and various composite materials. They improve efficiency and reduce noise during the operation.
Compressor Blower Fans
These devices are not needed in all cases, but only under the certain capacities and operating conditions, that create a risk of the compressor overheating. The need to use a blower for cooling the cylinder head, as a rule, is calculated and recommended by the manufacturers of compressors.
When blowing the compressor, the air stream is directed straightly to the piston head, which is very important for such systems, or to cool the oil that enters the crankcase through a special system. These fans can have a lower power and operate in the stationary mode, without additional settings. Blades can be made of plastic or steel and covered with special protective covers.