How does a hermetic compressor differ from an open compressor?

A hermetic compressor is characterized by its sealed unit design, which differentiates it from an open compressor. The hermetic compressor encases the motor and the compressor components in a single welded shell, preventing any contamination from outside air or moisture and thus ensuring the integrity of the refrigerant and lubricating oil inside. This sealed nature eliminates the need for serviceable parts or repairs because if a hermetic compressor fails, it typically requires replacement rather than repair.

In contrast, open compressors allow for access to their internal components, making them serviceable, but they also expose those components to outside contaminants, which can eventually lead to failures. The sealed design of the hermetic compressor is a significant advantage in terms of reliability and efficiency in both residential and commercial refrigeration applications.

The other options do not accurately reflect the fundamental characteristics of hermetic compressors: they are not necessarily larger than open compressors, they don't inherently consume more electricity, and while operational pressures can vary, hermetic compressors can operate at various pressures depending on their design and application.