ANSI ASHRAE-23-2005 pdf download Methods of Testing for Rating Positive Displacement Refrigerant Compressors and Condensing Units
5. REQUIREMENTS
5.1 Test Requirements.
5.1.1 Compressor or Condensing Unit Ratings. Each test data point used for rating a compressor or condensing unit shall consist of a primary test and a simultaneous, indepen- dent confirming test at a specified set of operating conditions. Compressor or condensing unit ratings shall be determined from refrigerant mass flow rates obtained by the primary method of test. However, each refrigerant mass flow rate obtained from the primary test (a time-averaged flow rate for a specific test data point) shall be considered to be valid only if the measured refrigerant mass flow rate from the corre- sponding confirming test (a time-averaged flow rate for the same test data point over the same time span) is within ±3% of the primary test measurement. For the purpose of ratings, the refrigerant mass flow rate (used in Equations 5-1 through 5-6) is defined as being the compressor or condensing unit suction mass flow rate. If a liquid refrigerant injection scheme is included in the test article, the liquid refrigerant injection shall be performed according to the manufacturer’s instructions with respect to pressure, temperature, quality, and refrigerant mass flow rate at the injection location. For example, when testing compressors or condensing units that use liquid refrigerant injection for cooling and that include a test method that measures total refrigerant mass flow rate on the discharge side of the test article, the liquid refrig- erant injection mass flow rate shall be measured by one of the methods listed in Table 1 and shall be subtracted from the total refrigerant mass flow rate to determine the compressor or condensing unit refrigerant mass flow rate. The resulting value for refrigerant mass flow rate shall be used in Equations 5-1 through 5-6.
5.1.2 Refrigerant Mass Flow Rate. Table 1 is a list of the test methods for determining refrigerant mass flow rates. The four calorimeter methods are described in Section 7.1.1 and the two flowmeter methods described in Section 7.1.2. The user shall designate one of these six test methods to be the pri- mary test method and one to be the confirming test method. Note that, although the method selected for the primary and confirming tests can be the same method, the primary and confirming tests must be simultaneous and completely inde- pendent.