SIST EN 13771-2:2008
Compressors and condensing units for refrigeration - Performance testing and test methods - Part 2: Condensing units
Compressors and condensing units for refrigeration - Performance testing and test methods - Part 2: Condensing units
This part of EN 13771 applies only to condensing units for refrigeration and describes a number of selected performance test methods. These methods provide sufficiently accurate results for the determination of the refrigerating capacity, power absorbed, refrigerant mass flow, isentropic efficiency and the coefficient of performance.
This European Standard applies only to performance tests conducted at the manufacturer's works or wherever the instrumention and load stability for testing to the accuracy required is available.
The type of measuring instrument and the allowable uncertainty within which measurements shall be made are listed in normative Annex A.
Kältemittel-Verdichter und Verflüssigungssätze für die Kälteanwendung - Leistungsprüfung und Prüfverfahren - Teil 2: Verflüssigungssätze
Dieser Teil der EN 13771 gilt nur für Verflüssigungssätze für die Kälteanwendung und beschreibt eine Reihe von ausgewählten Leistungsprüfverfahren. Diese Verfahren ermöglichen ausreichend genaue Ergebnisse zur Bestimmung von Kälteleistung, Leistungsaufnahme, Kältemittelmassenstrom und Leistungszahl.
Diese Europäische Norm gilt nur für Leistungsprüfungen, die beim Hersteller durchgeführt werden bzw. in Prüfeinrichtungen, deren Messgeräte und Laufstabilität eine Prüfung mit der erforderlichen Genauigkeit
sicherstellt.
Die Art der Messgeräte und die zulässige Messunsicherheit bei der Durchführung der Messungen sind in
Tabelle 2 angegeben.
Compresseurs et unités de condensation pour la réfrigération - Essais de performance et méthodes d'essais - Partie 2: Unités de condensation
La présente partie de l’EN 13771 s’applique uniquement aux unités de condensation pour la réfrigération et décrit une sélection de méthodes d’essai des performances. Ces méthodes fournissent des résultats d’une exactitude suffisante pour déterminer la puissance frigorifique, la puissance absorbée, le débit masse du fluide frigorigène et le coefficient de performance.
La présente Norme européenne s’applique uniquement aux essais de performance conduits dans les usines des fabricants ou en des endroits où l’on dispose de l’instrumentation et d’une stabilité de charge permettant d’effectuer les essais avec l’exactitude requise.
Le type d’instrument de mesure et les incertitudes de mesure admissible sont donnés dans le Tableau 2.
Kompresorji in kondenzacijske enote za hlajenje - Preskušanje lastnosti in preskusne metode - 2. del: Kondenzacijske enote
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kompresorji in kondenzacijske enote za hlajenje - Preskušanje lastnosti in preskusne metode - 2. del: Kondenzacijske enoteKältemittel-Verdichter und Verflüssigungssätze für die Kälteanwendung - Leistungsprüfung und Prüfverfahren - Teil 2: VerflüssigungssätzeCompresseurs et unités de condensation pour la réfrigération - Essais de performance et méthodes d'essais - Partie 2: Unités de condensationCompressors and condensing units for refrigeration - Performance testing and test methods - Part 2: Condensing units27.200Hladilna tehnologijaRefrigerating technology23.140VWURMLCompressors and pneumatic machinesICS:Ta slovenski standard je istoveten z:EN 13771-2:2007SIST EN 13771-2:2008en,fr,de01-april-2008SIST EN 13771-2:2008SLOVENSKI
STANDARD
SIST EN 13771-2:2008
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13771-2August 2007ICS 23.140; 27.200 English VersionCompressors and condensing units for refrigeration -Performance testing and test methods - Part 2: CondensingunitsCompresseurs et unités de condensation pour laréfrigération - Essais de performance et méthodes d'essai -Partie 2: Unités de condensationKältemittel-Verdichter und Verflüssigungssätze für dieKälteanwendung - Leistungsprüfung und Prüfverfahren -Teil 2: VerflüssigungssätzeThis European Standard was approved by CEN on 13 July 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13771-2:2007: ESIST EN 13771-2:2008
EN 13771-2:2007 (E) 2 Contents Page Foreword.4 1 Scope.5 2 Normative references.5 3 Terms, definitions and symbols.5 3.1 Terms and definitions.5 3.2 Symbols.6 3.3 Refrigerant circuit state points.8 4 General requirements.9 4.1 Test equipment.9 4.2 Calculation methods.9 4.2.1 Principle.9 4.2.2 Specific enthalpy.9 4.2.3 Refrigerant mass flow.9 4.2.4 Power absorbed.9 4.2.5 Basic equations.9 4.3 Requirements for the selection of test methods.10 4.4 Test procedure.10 4.4.1 General.10 4.4.2 Steady working conditions.10 4.4.3 Recording of measured data.10 4.5 Pressure and temperature measuring points.11 4.6 Oil circulation.11 4.7 Refrigerant composition.11 4.8 Calibration and requirements regarding measurement uncertainty.11 4.8.1 Calibration of calorimeters for methods A, B and C.11 4.8.2 Determination of the refrigerating capacity.12 4.8.3 Determination of the power absorbed by the condensing unit.12 4.8.4 Measuring instruments.12 4.9 Source of refrigerant data.13 4.10 Allowable deviations from the basic test conditions.13 4.11 Additional information.14 5 Test methods.14 5.1 General.14 5.2 List of test methods.14 5.2.1 Calorimetric methods.14 5.2.2 Flow meter methods.15 5.3 Method A: secondary fluid calorimeter on the suction side.15 5.3.1 Description.15 5.3.2 Calibration.15 5.3.3 Test procedure.16 5.3.4 Requirements.16 5.3.5 Determination of refrigerant mass flow.16 5.4 Method B: dry system refrigerant calorimeter on the suction side.16 5.4.1 Description.16 5.4.2 Calibration.17 5.4.3 Test procedure.17 5.4.4 Requirements.17 5.4.5 Determination of refrigerant mass flow.17 5.5 Method C: water-cooled condenser on the discharge side.18 5.5.1 Description.18 5.5.2 Calibration.18 SIST EN 13771-2:2008
EN 13771-2:2007 (E) 3 5.5.3 Test procedure.18 5.5.4 Requirements.19 5.5.5 Determination of refrigerant mass flow.19 5.6 Method D: refrigerant vapour flow meter on the suction side.19 5.6.1 Description.19 5.6.2 Test procedure.19 5.6.3 Requirements.19 5.6.4 Determination of refrigerant mass flow.20 5.7 Method E: refrigerant flow meter in the liquid line.20 5.7.1 Description.20 5.7.2 Test procedure.20 5.7.3 Requirements.21 5.7.4 Determination of the refrigerant mass flow.21 6 Determination of the power absorbed by the condensing unit.21 6.1 General.21 6.1.1 Introduction.21 6.1.2 Measurement for condensing units where the motor is not an integral part of the unit.21 6.1.3 Measurement for condensing units where the motor is an integral part of the condensing unit.21 6.1.4 Measurement of the power absorbed by the auxiliary components.22 6.2 Calculation.22 7 Test report.22 7.1 General.22 7.2 General information in the test report.22 7.3 Basic data.22 7.4 Test results.23 7.5 Additional information.23 Bibliography.25
SIST EN 13771-2:2008
EN 13771-2:2007 (E) 4 Foreword This document (EN 13771-2:2007) has been prepared by Technical Committee CEN/TC 113 “Heat pumps and air conditioning units”, the secretariat of which is held by AENOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2008 , and conflicting national standards shall be withdrawn at the latest by February 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 13771-2:2008
EN 13771-2:2007 (E) 5
1 Scope This part of EN 13771 applies only to condensing units for refrigeration and describes a number of selected performance test methods. These methods provide sufficiently accurate results for the determination of the refrigerating capacity, power absorbed, refrigerant mass flow and the coefficient of performance. This European Standard applies only to performance tests conducted at the manufacturer's works or wherever the instrumentation and load stability for testing to the accuracy required is available. The type of measuring instrument and the allowable uncertainties within which measurements shall be made are listed in Table 2. 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. EN 378-1:2000, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 1:
Basic requirements, definitions, classification and selection criteria EN 378-2, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 2:
Design, construction, testing, marking and documentation EN ISO 5167-1, Measurement of fluid flow by means of pressure differential devices inserted in circular cross- section conduits running full - Part 1: General principles and requirements (ISO 5167-1:2003) ISO 817, Refrigerants - Designation system ISO 5168, Measurement of fluid flow - Procedures for the evaluation of uncertainties 3 Terms, definitions and symbols 3.1 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1.1 refrigerating capacity
Φ0 product of the refrigerant mass flow and the difference between the specific enthalpy of the refrigerant at the inlet of the condensing unit and that at the outlet of the condensing unit. The refrigerant at the unit inlet is superheated above the suction dew point temperature to the stated value. The liquid is at a pressure corresponding to the outlet of the condensing unit 3.1.2 power absorbed
3.1.2.1 power absorbed by the condensing unit where the motor is an integral part of the unit, Pcm electrical power input at the compressor motor terminals plus the power to all other devices (e.g. fan motor) forming an integral part of the condensing unit SIST EN 13771-2:2008
EN 13771-2:2007 (E) 6 3.1.2.2 power absorbed by the condensing unit where the motor is not supplied as an integral part in the unit, Pcs electrically power input at the compressor shaft plus the power to all other devices (e.g. fan motor) forming an integral part of the condensing unit 3.1.3 refrigerant mass flow
qm
refrigerant mass flow at the condensing unit inlet
3.1.4 coefficient of performance
3.1.4.1 coefficient of performance COPrm ratio of the refrigerating capacity to the power absorbed as defined in 3.1.1 and 3.1.2.1 3.1.4.2 coefficient of performance COPrs ratio of the refrigerating capacity to the power absorbed as defined in 3.1.1 and 3.1.2.2 NOTE All the above are at the basic test condition. 3.1.5 oil circulation in the refrigerating system
xoil ratio of the measured oil mass flow to the mass flow of the circulating oil/refrigerant mixture 3.1.6 condensing unit factory assembled unit comprised of refrigeration compressor and motor, condenser and any necessary associated ancillaries
3.2 Symbols For the purposes of this document, the symbols found in Table 1 apply. SIST EN 13771-2:2008
EN 13771-2:2007 (E) 7
Table 1 — Symbols Symbol Designation SI unit c Specific heat capacity of liquid J/(kg K) coil Specific heat capacity of oil J/(kg K) COPrm Coefficient of performance as defined in 3.1.4.1 - COPrs Coefficient of performance as defined in 3.1.4.2 - f Nominal electrical frequency Hz fa Actual electrical frequency Hz F Heat leakage factor W/K hl 2 Specific enthalpy of liquid refrigerant at bubble point corresponding to the pressure at the compressor outlet according to the basic test conditions J/kg hlc4 Specific enthalpy of liquid refrigerant at the outlet of the condensing unit J/kg hl 5 Specific enthalpy of liquid refrigerant at the inlet in the expansion device J/kg hg c 1 Specific enthalpy of the refrigerant vapour at the condensing unit inlet at the basic test conditions J/kg hg 3 Specific enthalpy of the refrigerant vapour at the inlet of the condenser J/kg hg 6 Specific enthalpy of the refrigerant vapour at the outlet of the calorimeter J/kg n Nominal compressor speed 1/min na Actual compressor speed 1/min Pc Power absorbed by the unit at the basic test conditions W Pa Actual power absorbed by the compressor W Pcm Power absorbed by the condensing unit (for motor compressors) W Pcs Power absorbed by the condensing unit (for externally driven compressors) W PF Power absorbed by all other auxiliary components (fans, etc.) W pgc 1 Absolute pressure, condensing unit inlet MPa pg 2 Absolute pressure, compressor outlet MPa pg 3 Pressure of the refrigerant vapour entering the condenser MPa pg 6 Pressure of the refrigerant
vapour of the evaporator outlet MPa plc4 Pressure of the refrigerant liquid leaving the condensing
unit MPa pl 5 Pressure of the refrigerant liquid entering the expansion device MPa ps Absolute pressure of the secondary fluid MPa qm Refrigerant mass flow as determined by the test kg/s qm
0 Refrigerant mass flow at the basic test conditions kg/s qmf Fluid mass flow kg/s qmx Mass flow of liquid refrigerant/oil mixture kg/s qv Refrigerant volume flow m3/s qvx Volume flow of refrigerant/oil mixture m3/s ta Ambient temperature °C tA in Air inlet temperature at air-cooled condenser
°C tF in Fluid inlet temperature at evaporator / water-cooled condenser
°C tF out Fluid outlet temperature at evaporator / water-cooled condenser
°C tc Mean surface temperature of the calorimeter at the basic test conditions °C tga Actual temperature at the condensing unit inlet °C tgc 1 Refrigerant vapour temperature at the condensing unit inlet at the basic test conditions °C tg 3 Temperature of the refrigerant vapour entering condenser °C tg 6 Temperature of the refrigerant vapour at the evaporator outlet °C SIST EN 13771-2:2008
EN 13771-2:2007 (E) 8 tl 2 Saturation temperature of the liquid refrigerant corresponding to the pressure at the compressor outlet °C tlc 4 Temperature of the refrigerant liquid leaving the condensing unit °C tl 5 Temperature of the refrigerant liquid entering the expansion device °C tr The mean of the
bubble and dew point temperature of the refrigerant °C ts Saturation temperature of the secondary fluid °C tx Reference temperature °C U Nominal electrical voltage V xoil Oil circulation in the refrigerating system, expressed in kilogram per kilogram of mixture kg/kg vga Actual specific volume of refrigerant vapour at the condensing unit inlet
m3/kg vg c1 Specific volume of refrigerant vapour at the condensing unit
inlet at the basic test conditions m3/kg ρm Density of refrigerant corresponding to pressure and temperature at which the flow rate is measured kg/m3 i Heat flow to the calorimeter W n Electrical power for the heater W 0 Refrigerating capacity of the condensing unit at the basic test conditions W
3.3 Refrigerant circuit state points Figure 1b) shows the state of the refrigerant as it flows through the refrigerating circuit shown in Figure 1a).
a) Circuit diagram b) Pressure vs enthalpy diagram Key 1 Condenser (including any receiver and/or sub-cooler forming an integral part of the unit) 2 Expansion device 3 Compressor 4 Evaporator Figure 1 — Refrigerant circuit SIST EN 13771-2:2008
EN 13771-2:2007 (E) 9 4 General requirements 4.1 Test equipment All equipment shall comply with the requirements of EN 378-2. 4.2 Calculation methods 4.2.1 Principle The determination of the refrigerating capacity of a condensing unit at the basic test conditions comprises: evaluation of the actual mass flow of refrigerant at the condensing unit inlet (qm) when operating within the limits allowed to the basic test conditions in Table 3; correction of this mass flow to that, at the basic test conditions using the ratio of the actual specific volume (vga) of the refrigerant vapour at the condensing unit inlet to the specific volume of the vapour at the basic test conditions (vgc 1); product of the corrected mass flow and the difference between the specific enthalpies at the basic test conditions of the refrigerant vapour at the condensing unit inlet (hg c1), and the liquid refrigerant at the condensing unit outlet (hlc 4). NOTE For the purpose of this standard it is assumed that the volume flow rate is constant when the condensing unit is operating within the limits allowed in Table 3. 4.2.2 Specific enthalpy The value of the specific enthalpy is listed in the recognised data of the thermodynamic properties of the refrigerant used.
4.2.3 Refrigerant mass flow The refrigerant mass flow is either measured directly or calculated from measured values. 4.2.4 Power absorbed Within a superheat range of ± 5 K it is assumed that the power consumption will stay constant. 4.2.5 Basic equations The refrigerant mass flow qm determined by measurement is converted to that at the basic test conditions using the following equation: a1 gcagm0m=nnvvqq⋅ (1) The refrigerating capacity as defined in 3.1.1 for condensing units is calculated using the following equation: )(4lc1gc0m0hhq−⋅=Φ (2) The power absorbed by the condensing unit as defined in 3.1.2 is converted from the measured power absorbed to that at the basic test conditions using the following equation: SIST EN 13771-2:2008
EN 13771-2:2007 (E) 10 FPnnPPaa+⋅=c (3)
where
Pc is the power absorbed by the condensing unit; PF
is the power absorbed by the fan and/or other auxiliary components. For motor compressors, the correction factor n/na is replaced by f/fa. NOTE It is not necessary to correct PF because this change is insignificant in comparison to Pc. The coefficient of performance COPrm as defined in 3.1.4.1 is calculated using the following equation: cm0rmPCOPΦ= (4a) The coefficient of performance COPrs as defined in 3.1.4.2 is calculated using the following equation: cs0rsPCOPΦ= (4b) 4.3 Requirements for the selection of test methods Two different test methods from those taken from Clause 5 shall be used at the same time. The results of the two methods shall correlate within 4 %. The test result is the mean value of the two methods. A second method is not necessary where testing devices are in constant use and subject to periodical calibration in accordance with EN ISO 9001. 4.4 Test procedure 4.4.1 General The tests described refer exclusively to a condensing unit operating continuously under conditions so that, for a specified period, fluctuations in all the factors likely to affect the results of a test remain within the limits prescribed and show no definite tendency to move outside these limits. These conditions are described as steady working conditions and are defined precisely in 4.10. 4.4.2 Steady working conditions After the condensing unit has been started, adjustments shall be made during a preliminary run until the measurements required are within the steady working conditions. Steady working conditions shall be reached for at least 15 min before recording commences and shall be maintained so during the full period of the test. 4.4.3 Recording of measured data Once steady working conditions have been reached, the measured data shall be recorded. At least one complete measuring cycle shall be carried out every minute. The recording period shall be at least 15 min. The mean value of any measured quantity shall be calculated from all the values of this quantity during the recording period. SIST EN 13771-2:2008
EN 13771-2:2007 (E) 11 4.5 Pressure and temperature measuring points The pressure and temperature at the inlet of the condensing unit shall be measured at the same place. This shall be located in a straight run of pipe at a distance of at least four times the pipe diameter, but not less than 150 mm from the shut-off valve or connection. The diameter of the pipe shall be consistent with that of the connection on the condensing units for a length of at least eight times the pipe diameter. The pressure and temperature at the outlet of the condensing unit shall be measured in a similar manner. 4.6 Oil circulation
The quantity of oil in circulation shall be determined after the test. From the liquid phase of the refrigerant circuit the refrigerant/oil mixture shall be poured into a collecting device intended for this specific purpose and the oil fraction determined.
In case of repeated tests of a compressor type for the known quantity of oil in circulation, random sampling may be sufficient. Alternative procedures with the same accuracy may be used. The collecting device shall be constructed according to EN 378-2. 4.7 Refrigerant composition The composition of any refrigerant to be used in a test shall be in accordance with ISO 817. NOTE Zeotropic refrigerants have a certain composition in the as-specified condition. Changes in pressure and temperature can cause a change in the concentration of the different components in the circulating refrigerant. This can be exacerbated by unfavourable distribution of the refrigerant in the circuit, leakage from the system and selective oil solubility. The thermodynamic properties will also change with resulting inaccuracies in the determination of performance data. 4.8 Calibration and requirements regarding measurement uncertainty 4.8.1 Calibration of calorimeters for methods A, B and C 4.8.1.1 Calorimeters for methods A, B and C shall be calibrated by determining a heat leakage factor, )(attF−=xiΦ (5) which describes the heat exchange between the calorimeter and the ambient temperature. 4.8.1.2 The reference temperature tx depends on the calorimeter type and determines the heat exchange to the ambient temperature. It can be: a) saturation temperature ts of the secondary fluid (e.g. method A); b) mean surface temperature tc of the calorimeter (e.g. method B); c) mean of refrigerant bubble and dew point temperatures tr of the calorimeter (e.g. method C). 4.8.1.3 The following method shall be used to determine the heat leakage factor: Before starting the test maintain the ambient temperature
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