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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 5773-2004 The method of performance test for positive displacement refrigerant compressors. The following technical changes have been made with respect to GB/T 5773-2004:
——method of performance test for compressor with economizer or flash-tank is added;
——method of performance test for transcritical cycle compressor is added;
——evaluation on compressor heating capacity is added;
——example of analysis for performance measurement uncertainty of compressor is added.
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of National Technical Committee on Automobiles of Standardization Administration of China (SAC/TC 238).
The previous edition of standard replaced by this standard is as follow:
——GB/T 5773-2004.
The method of performance test for positive displacement refrigerant compressors
1 Scope
This standard specifies the terms and definitions, test requirements, test methods and input power, cooling (heating) coefficient of performance, volume efficiency, isentropic efficiency, and calculation of test deviation of positive displacement refrigerant compressors.
This standard is applicable to performance tests for single-stage positive displacement refrigerant compressor (hereinafter referred to as "single-stage compressor"), positive displacement refrigerant compressor with economizer (hereinafter referred to as "compressor with economizer") and positive displacement refrigerant compressor with flash-tank (hereinafter referred to as "compressor with flash-tank"), and serves as reference for the test of other compressors.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2624.1 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 1: General principles and requirements
GB/T 2624.2 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 2: Orifice plates
GB/T 2624.3 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 3: Nozzles and Venturi nozzles
GB/T 2624.4 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full - Part 4: Venturi tubes
GB 9237 Mechanical refrigerating systems used for cooling and heating - Safety requirements
GB/T 29030-2012 Positive displacement CO2 refrigerant compressor (unit)
JB/T 7249 Refrigerating equipment - Terms
3 Terms and definitions
For the purposes of this document, the terms and definitions given in JB/T 7249 and the following apply.
3.1
positive displacement refrigerant compressor
refrigerant compressor improving the refrigerant vapor pressure by reducing the internal volume of the compression chamber
3.2
compressor refrigerating capacity
the measured mass flow of refrigerant flowing through the evaporator in refrigeration cycle of the compressor multiplied by the difference between the specific enthalpy of refrigerant gas at compressor suction port and that of refrigerant liquid before expansion in evaporator in refrigeration cycle of the compressor under the specified refrigerating capacity test conditions
Note: the unit is W.
3.3
compressor heating capacity
the measured mass flow of refrigerant flowing through the exhaust side of compressor multiplied by the difference between the specific enthalpy of refrigerant gas at compressor exhaust port and that of refrigerant liquid before expansion in evaporator (air compensating circuit) in refrigeration cycle of the compressor under the specified heating capacity test conditions
Note: the unit is W.
3.4
volume efficiency
ratio of the actual volumetric flow of the compressor under suction state measured at the specified position to the theoretical gas transmission quantity of the compressor
3.5
input power
the input shaft power of open-type compressor; the input power of motor, or other auxiliary power necessary for maintaining the normal operation of enclosed (either semi-hermetically and hermetically) compressor (e.g., the consumed power of the external lubricating oil pump)
Note: the unit is W.
3.6
isentropic efficiency
ratio of the sum of all-stage actual mass flows of refrigerant of the compressor and the product of corresponding specific enthalpy variation in isentropic process to the input power of the compressor
3.7
cooling (heating) coefficient of performance
ratio of refrigerating (heating) capacity to input power of the compressor
Note: the value is expressed in W/W.
4 Test requirements
4.1 General requirements
4.1.1 Non-condensable gas in the test system is eliminated. It is confirmed that there is no leakage of refrigerant.
4.1.2 There shall be sufficient refrigerant in the system. There shall be certain amount of lubricating oil necessary for normal operation in the compressor.
4.1.3 An effective oil separator shall be arranged on the exhaust pipe so that the oil content of the refrigerant liquid in the refrigeration cycle of the compressor does not exceed 1.5% (by mass). Refer to Annex A for the measurement method.
4.1.4 The pressure and temperature of the suction and exhaust ports of the compressor shall be measured at the same measuring point, which shall be at the straight pipe section 0.3m away from the suction and exhaust shut-off valves, or at the straight pipe section 0.15m away from the ends of the suction and exhaust pipe orifices for a closed compressor without valve.
4.1.5 There shall be no abnormal air flow around the compressor under test.
4.1.6 The equipment extracting refrigerant-oil mixture sample for measuring oil content is provided.
4.2 Test requirements
4.2.1 There are two methods of refrigerating capacity performance test for single-stage compressors, i.e., X method and Y method, which are subjected to simultaneous measurement; the deviation between test results obtained by X method and Y method shall be within ±4%, and the average of test results calculated by the two methods shall prevail.
4.2.2 Only one test method (X method or Y method) may be adopted for the heating capacity test of a compressor or the refrigerating capacity test of a compressor with economizer or flash-tank.
4.2.3 During the compressor, the system shall establish a heat balance state; generally, the test duration is not less than 1h. The measured data shall be recorded after the test conditions have been stabilized for half an hour; measurement is carried out every other 15min until the data of four measurements are in accordance with those specified in Table 2, 4.2.1 and 4.2.2. If the test data is automatically acquired by a computer, the continuous acquisition duration of measured data is not less than 30min. The pressure, temperature, flow and liquid level are allowed to be regulated slightly during the record cycle of test data.
4.2.4 Types of test methods
The compressor test shall meet the requirements of 4.2.1 and 4.2.2. Data specified in the test report (see 4.5.2) and the additional data required for each test method shall be measured during each test cycle.
a) Test methods for subcritical cycle compressor
Nine different test methods are as follows:
Method A: secondary refrigerant calorimeter method (see 5.1.1);
Method B: full-liquid refrigerant calorimeter method (see 5.1.2);
Method C: dry refrigerant calorimeter method (see 5.1.3);
Method D1: suction pipe refrigerant gas flowmeter method (see 5.1.4);
Method D2: exhaust pipe refrigerant gas flowmeter method (see 5.1.4);
Method F: refrigerant liquid flowmeter method (see 5.1.5);
Method G: water-cooled condenser calorimeter method (see 5.1.6);
Method J: refrigerant gas cooling method (see 5.1.7);
Method K: compressor exhaust pipe calorimeter method (see 5.1.8).
b) Test methods for transcritical cycle compressor
Seven different test methods are as follows:
Method A: secondary refrigerant calorimeter method (see 5.2.1);
Method B: full-liquid refrigerant calorimeter method (see 5.2.2);
Method C: dry refrigerant calorimeter method (see 5.2.3);
Method D1: suction pipe refrigerant gas flowmeter method (see 5.2.4);
Method D2: exhaust pipe refrigerant gas flowmeter method (see 5.2.5);
Method J: refrigerant gas cooling method (see 5.2.6);
Method K: compressor exhaust pipe calorimeter method (see 5.2.7).
4.2.5 Selection of X method and Y method
For a subcritical cycle compressor, any of the performance test methods A, B, C, D1, D2, F, G, and K may be used as X method.
For a transcritical cycle compressor, any of the performance test methods A, B, C, D1, D2 and K may be used as X method.
Any test method, except these listed below, may also be used as Y method.
a) Any test method used as X method;
b) Any method with measured quantity the same as that of X method. For example, if X method is used for measuring the gas flow of the compressor exhaust pipe, other test methods for measuring the gas flow of the compressor exhaust pipe are no longer selected as Y method (such as Method D2 cannot be combined with Method K);
c) Any method with measurement principle the same as that of X method. For example, if D1 refrigerant gas flowmeter method is used as X method, D2 refrigerant gas flowmeter method is no longer selected as Y method.
4.2.6 Combination of X method and Y method
Table 1 specifies the permitted and recommended combinations of X method and Y method for performance test of subcritical cycle compressor.
Table 2 specifies the permitted and recommended combinations of X method and Y method for performance test of transcritical cycle compressor.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Test requirements
5 Test methods
6 Power input calculation
7 Calculation of cooling (heating) coefficient of performance
8 Calculation of volume efficiency
9 Calculation of isentropic efficiency
10 Deviation between tests with X method and Y method
11 Analysis for measurement uncertainty of performance
Annex A (Informative) Method of measurement for oil content
Annex B (Informative) Symbols and meanings in equations
Annex C (Informative) Example of analysis for performance measurement uncertainty
