How is evaporator pressure commonly measured?

Evaporator pressure in refrigeration systems is commonly measured in inches of mercury (Hg), which is a standard unit of pressure measurement in many applications, particularly in the context of evaporators and refrigeration cycles. This measurement reflects the height of a column of mercury that is supported by the pressure being measured; thus, it provides a direct indication of how much pressure is exerted by the refrigerant in the evaporator.

Using inches of mercury allows operators to easily assess the system's performance, as it relates closely to the conditions of vaporization for the refrigerant at specific temperatures. This correlation is crucial in system design and troubleshooting. Additionally, industry standards often use inches of mercury when referring to the pressures in various stages of refrigeration processes, particularly those involving the evaporator section.

The other measurement units mentioned, such as PSIG (pounds per square inch gauge), although also valid for pressure measurement, are not as commonly used in the context of evaporator pressure specifically in certain applications. Pascals, a SI unit, and other references might be used in different contexts but do not have the same immediate relevance in traditional evaporator discussions as inches of mercury. Understanding the context and common usage is key to recognizing why inches of mercury is the accepted standard in this scenario