scope:

This Japanese Industrial Standard specifies the details of capacity evaluation for direct expansion refrigerating unit coolers (hereafter referred to as unit coolers).

It is applicable to unit coolers using R410A and R404A refrigerants.

NOTE 1 This Standard provides specific figures and calculation methods for unit coolers using copper pipes of 9.52 mm, 12.70 mm and 15.88 mm in diameter that are fitted with smooth aluminium plate fins. Provided the manufacturer prepares the necessary data by testing, this Standard is also applicable to unit coolers that use other pipe sizes and are fitted with smooth aluminium plate fins or formed aluminium fins.

NOTE 2 The scope of this Standard is limited to "refrigerating" unit coolers so as to exclude air conditioning unit coolers with an evaporating temperature 0 °C or higher which, if included, would cause variation of performance according to the temperature and humidity conditions at the unit cooler inlet, and complicate the calculation formula and diagrams.

The heat exchanging part of a unit cooler is considered to be a dry heating surface without frosting.