Question

Which two methods are used to cool most hermetic compressors?

1) Water cooled and pressure cooled.
2) Air cooled and subcooled.
3) Refrigerant cooled by absorption.
4) Refrigerant cooled and air cooled.

Answer 1

The correct answer is option 4, as most hermetic compressors are cooled using refrigerant cooling and air cooling methods to effectively dissipate heat generated during compression.

Step-by-step explanation:

The correct answer is option 4) Refrigerant cooled and air cooled. These are the two primary methods used to cool most hermetic compressors. In air-cooled systems, ambient air is used to dissipate the heat from the compressor. This is often done with the help of a fan blowing over the compressor or the condenser coils. On the other hand, refrigerant cooling involves the refrigerant itself absorbing heat from the compressor, which is then carried away and released at the condenser.

For example, in a simple heat pump or refrigerator, the compressor is part of a cycle where it compresses the refrigerant, raising its pressure and temperature. The refrigerant then travels through the condenser coils, where it releases heat to the environment and condenses into a liquid. After that, it goes through an expansion valve and absorbs heat at the evaporator, effectively cooling down the interior space or the component itself in a closed system. Throughout this process, the compressor may be cooled by the refrigerant before it gets compressed again or by air to maintain an optimal operating temperature.