Which factor is NOT important when sizing a refrigeration system for a facility?

When sizing a refrigeration system for a facility, careful consideration of various factors is crucial to ensure optimal performance and efficiency. Among the listed factors, the heat load of the facility plays a vital role, as it determines the amount of thermal energy the system must remove to maintain desired temperatures. Space requirements for installation are also significant; sufficient space must be available not only for the refrigeration unit but for airflow, maintenance access, and efficiency.

Similarly, understanding the usage patterns of the facility is essential. This insight enables the operator to determine the peak refrigeration demand periods, which directly affect the system's capacity and operational efficiency.

In contrast, while the availability of a power supply is necessary for the operation of any electrical system, it is not a factor that directly influences the sizing of the refrigeration system itself. The sizing is more closely related to how much heat needs to be removed and the physical constraints of the installation, rather than the specifics of the power supply available. Therefore, it is the least critical factor when determining the size of the refrigeration system.