GB/T 5773-2016The method of performance test for positive displacement refrigerant compressors (English PDF)

3.1 Positive displacement refrigerant compressor

The refrigerant compressor that relies on the reduction of the internal volume of the compression chamber to increase the refrigerant vapor pressure.

3.2 Compressor refrigerating capacity

Under the specified refrigeration capacity test conditions, the mass flow rate of refrigerant flowing through the evaporator in the refrigeration cycle where the compressor is located multiplied by the difference between the refrigerant gas specific enthalpy at the compressor suction port and the refrigerant liquid specific enthalpy before expansion in the evaporator in the refrigeration cycle where the compressor is located.

3.3 Compressor heating capacity

Under the specified heating capacity test conditions, the mass flow rate of refrigerant flowing through the exhaust side of the compressor multiplied by the difference between the specific enthalpy of the refrigerant gas at the compressor exhaust port and the specific enthalpy of the refrigerant liquid before expansion in the evaporator (air supply circuit) in the refrigeration cycle where the compressor is located.

Note: The unit is W.

4.1 General regulations

4.1.1 Remove non-condensable gases from the test system. Check that there is no refrigerant leakage.

4.2 Test regulations

4.2.1 The compressor refrigerating capacity performance test of a single-stage compressor includes two test methods, namely, method X and method Y. The two methods shall be tested simultaneously; the deviation between the test results of method X and method Y shall be within ±4%; the average value of the measurement and calculation results of method X and method Y shall prevail.

4.2.2 For the compressor heating capacity test of the compressor and the compressor refrigerating capacity test of the compressor equipped with economizer or flash-tank, only one test method (method X or method Y) may be used for measurement.

4.2.4 Types of test methods

The compressor test shall comply with the requirements of 4.2.1 and 4.2.2. During each test cycle, the data specified in the test report (see 4.5.2) shall be measured, together with any additional data required for each test method.

4.2.5 Selection between test method X and method Y

For subcritical cycle compressors, any of the performance test methods A, B, C, D1, D2, F, G and K may be used as method X.

4.2.6 Combination of test method X and method Y

4.4 Provisions for measuring instruments and accuracy

4.4.1 General provisions

4.4.2 Temperature measurement

4.4.2.1 Instrumentation

Instruments for measuring temperature include. glass mercury thermometer, thermocouple, resistance thermometer, semiconductor thermometer and differential thermometer.

4.4.2.2 Accuracy

The accuracy requirements of the measuring instrument are as follows. […]

4.4.2.3 Measurement regulations

The following requirements shall also be met during measurement.

4.4.3 Pressure measurement

4.4.3.1 Instrumentation

Instruments for measuring pressure include. spring tube pressure gauge, pressure sensor and mercury column atmospheric pressure gauge, etc.

4.4.3.2 Accuracy

For all pressure measuring instruments, the accuracy of absolute pressure reading or differential pressure reading shall be within ±1.0%.

4.4.3.3 Measurement regulations

When measuring atmospheric pressure using a mercury barometer, the reading shall be corrected for temperature.

4.4.4 Flow measurement

4.4.5 Electrical measurements

4.4.5.1 Instrumentation

Electrical measuring instruments include. power meter (including indicating and integrating types), ammeter, voltmeter, power factor meter, frequency meter and transformer.

4.4.5.2 Accuracy

The accuracy requirements of the measuring instrument are as follows. […]

4.4.5.3 Measurement regulations

The power meter measurement value shall be above 1/3 of the full scale (when using the "two-power meter" method for measurement, the measured value of one of the power meters can be less than 1/3 of the full scale). When using the "two-power meter" method or the "three-power meter" method to measure the power of a three-phase AC motor, the indicated current and voltage values shall not be less than 60% of the rated current and voltage values of the power meter.

For digital power meters. If a current transformer is used, the actual displayed current value shall not be less than 20% of the transformer range.

4.4.6 Compressor power measurement

4.5.2 Test report

4.5.2.1 General data

It mainly includes.

4.5.2.2 Test conditions

It mainly includes.

4.5.2.3 Test method

Method X and method Y.

4.5.2.4 Average value of test measured values

It mainly includes.

4.5.2.5 Test result data

It mainly includes.

5.1 Test methods for subcritical cycle compressors

5.1.1 Method A. Second refrigerant calorimeter method (Figure 1)

The performance test process of single-stage compressor is shown in Figure 1a); the performance test process of compressor equipped with economizer is shown in Figure 1b); the performance test process of compressor equipped with flash-tank is shown in Figure 1c).

5.1.1.1 Construction

The second refrigerant calorimeter is composed of a group of direct evaporation coils as an evaporator, which is suspended on the upper part of an insulated pressure container.

The electric heater is installed at the bottom of the container and is immersed in the second refrigerant in the container.

5.1.1.3 Test procedure

5.1.1.3.1 The suction pressure of the compressor refrigerant is regulated by the main circuit expansion valve, and the suction temperature is regulated by the electric heating capacity input to the second refrigerant.

5.1.2 Method B. Fully liquid refrigerant calorimeter method (Figure 2)

The performance test process of single-stage compressor is shown in Figure 2a); the performance test process of compressor equipped with economizer is shown in Figure 2b); the performance test process of compressor equipped with flash-tank is shown in Figure 2c).

5.1.2.3.5 During the test period, the change in the compressor refrigerating capacity caused by the fluctuation of the input heat shall not exceed 1%. If the heater is working intermittently, the change in the saturation temperature (or dew point temperature) corresponding to the refrigerant liquid shall be less than ±0.5 °C.

5.1.2.3.6 Additional data include

5.1.2.4 Refrigerant flow rate calculation

6.1 Motor input power measurement

6.2 Compressor shaft power calculation

6.3 Input power

The input power shall be the above motor input power or compressor shaft power after correction plus the auxiliary power required to maintain the compressor operation. The above power shall be corrected for open or closed compressors according to Formula (24) to obtain the input power.

7.1 Compressor refrigerating capacity

7.1.1 Calculate the actual compressor refrigerating capacity under specified working conditions as follows.

7.1.2 Calculate the compressor refrigerating capacity based on the measured compressor refrigerating capacity after speed correction or frequency correction according to Formula (28). […]

7.2 Cooling coefficient of performance

Calculate the cooling coefficient of the compressor according to Formula (29).

7.3 Compressor heating capacity

7.4 Heating coefficient of performance

Calculate the heating coefficient of the compressor according to Formula (35).