SIST EN 328:2014
(Main)Heat exchangers - Forced convection unit air coolers for refrigeration - Test procedures for establishing the performance
Heat exchangers - Forced convection unit air coolers for refrigeration - Test procedures for establishing the performance
This European Standard is applicable to non-ducted unit air coolers for refrigeration operating:
a) with direct dry expansion of a refrigerant;
b) with liquid overfeed by pump circulation of a refrigerant;
c) with a liquid.
This standard specifies uniform methods of performance assessment to test and ascertain the following:
— product identification;
— standard capacity;
— standard liquid pressure drop;
— standard refrigerant pressure drop (for operation with liquid overfeed by pump circulation only);
— nominal air flow rate;
— nominal fan power.
It does not cover evaluation of conformity. It is not applicable to air coolers for duct mounting or with natural air convection. This standard does not cover technical safety aspects.
Wärmeaustauscher - Prüfverfahren zur Bestimmung der Leistungskriterien von Ventilatorluftkühlern
Diese Europäische Norm gilt für kanallose Ventilatorluftkühler zum Einsatz in Kälteanlagen
a) mit direkter trockener Expansion eines Kältemittels;
b) mit Flüssigkeitspumpenumwälzung eines Kältemittels;
c) mit einem Kälteträger.
Diese Norm legt einheitliche Verfahren zur Leistungsbewertung fest, um Folgendes zu prüfen und sicherzu-stellen:
a) Produktkennzeichnung;
b) Normleistung;
c) kälteträgerseitiger Normdruckabfall;
d) kältemittelseitiger Normdruckabfall (nur für den Betrieb mit Flüssigkeitspumpenumwälzung);
e) Nenn-Luftdurchfluss;
f) Nenn-Ventilatorleistungsaufnahme.
Diese Norm behandelt nicht die Konformitätsbewertung.
Sie gilt nicht für kanalmontierte Ventilatorluftkühler oder Luftkühler mit freier Konvektion.
Sicherheitstechnische Gesichtspunkte sind nicht Gegenstand dieser Europäischen Norm.
Échangeurs thermiques - Procédures d'essai pour la détermination de la performance des aérofrigorifères à convection forcée
La présente Norme européenne s'applique aux aérofrigorifères non raccordés utilisés dans les situations suivantes :
a) expansion directe à sec du fluide frigorigène ;
b) suralimentation en liquide par circulation du fluide frigorigène au moyen d'une pompe ;
c) fonctionnement avec un liquide.
La présente norme spécifie des méthodes uniformes d'évaluation de la performance afin de soumettre à l'essai et de déterminer les caractéristiques suivantes :
d) identification du produit ;
e) puissance normale ;
f) chute de pression normale du liquide ;
g) chute de pression normale du fluide frigorigène (uniquement pour les utilisations avec suralimentation en liquide par circulation du fluide frigorigène au moyen d'une pompe) ;
h) débit d'air nominal ;
i) puissance nominale du ventilateur.
La présente norme ne traite pas de l'évaluation de la conformité.
Elle ne s'applique pas aux aérofrigorifères destinés à être montés dans des gaines ou à convection naturelle par air.
La présente norme ne traite pas des aspects techniques de sécurité.
Prenosniki toplote - Hladilniki zraka s prisilno konvekcijo za hlajenje - Postopki preskušanja za ugotavljanje lastnosti
Ta evropski standard se uporablja za brezkanalne hladilnike zraka za hlajenje, ki delujejo:
a) z neposredno suho širitvijo hladiva;
b) s pretiranim dotokom tekočine s črpalnim kroženjem hladiva;
c) s tekočino.
Ta standard določa enotne metode ocenjevanja lastnosti za preskušanje in ugotavljanje naslednjega:
– identifikacije proizvoda;
– običajne kapacitete;
– običajnega padca tlaka na strani tekočine;
– običajnega padca tlaka na strani hladiva (le za delovanje s pretiranim dotokom tekočine s črpalnim kroženjem);
– nazivnega pretoka zraka;
– nazivne moči ventilatorja.
Standard ne obravnava vrednotenja skladnosti. Ne uporablja se za hladilnike zraka za kanalsko vgradnjo ali z naravno konvekcijo zraka. Ta standard ne obravnava tehničnih varnostnih vidikov.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 328:2014
01-november-2014
1DGRPHãþD
SIST EN 328:1999
SIST EN 328:1999/A1:2004
Prenosniki toplote - Hladilniki zraka s prisilno konvekcijo za hlajenje - Postopki
preskušanja za ugotavljanje lastnosti
Heat exchangers - Forced convection unit air coolers for refrigeration - Test procedures
for establishing the performance
Wärmeaustauscher - Prüfverfahren zur Bestimmung der Leistungskriterien von
Ventilatorluftkühlern
Échangeurs thermiques - Procédures d'essai pour la détermination de la performance
des aérofrigorifères à convection forcée
Ta slovenski standard je istoveten z: EN 328:2014
ICS:
23.120 =UDþQLNL9HWUQLNL.OLPDWVNH Ventilators. Fans. Air-
QDSUDYH conditioners
27.060.30 Grelniki vode in prenosniki Boilers and heat exchangers
toplote
SIST EN 328:2014 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 328:2014
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SIST EN 328:2014
EUROPEAN STANDARD
EN 328
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2014
ICS 23.120; 27.060.30 Supersedes EN 328:1999
English Version
Heat exchangers - Forced convection unit air coolers for
refrigeration - Test procedures for establishing the performance
Echangeurs thermiques - Aérofrigorifères à convection Wärmeübertrager - Ventilatorluftkühler - Prüfverfahren zur
forcée pour la réfrigération - Procédures d'essai pour la Leistungsfeststellung
détermination de la performance
This European Standard was approved by CEN on 22 May 2014.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC 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 translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 328:2014 E
worldwide for CEN national Members.
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SIST EN 328:2014
EN 328:2014 (E)
Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .6
4 Symbols . 11
5 Standard capacity . 13
5.1 Basis of standard capacity data . 13
5.2 Standard conditions for the cooling capacity . 14
5.2.1 General . 14
5.2.2 Refrigerants . 14
5.2.3 Liquids . 15
5.3 Conditions for the nominal air flow rate . 15
5.4 Conditions for nominal fan power . 15
6 Manufacturer's data . 15
7 Measurements . 16
7.1 Uncertainty of measurements . 16
7.2 Measurement criteria . 17
7.2.1 Pipe side temperature measurement . 17
7.2.2 Superheating temperature . 18
7.2.3 Temperature at expansion device inlet . 18
7.2.4 Liquid temperatures . 18
7.2.5 Water temperatures (balancing air heater) . 18
7.2.6 Air temperature measurement . 18
7.2.7 Pressure measuring points . 19
7.2.8 Flow rates . 19
7.2.9 Oil content . 19
7.2.10 Non azeotropic refrigerant . 19
8 Testing methods and equipment . 20
8.1 Testing methods . 20
8.1.1 Capacity . 20
8.1.2 Air flow . 20
8.1.3 Heat exchange with the ambient . 20
8.2 Equipment . 20
8.2.1 Calorimeter room . 20
8.2.2 Refrigerant / liquid pipes . 22
8.2.3 Expansion device. 22
8.2.4 Flashgas . 22
8.2.5 Air flow measurement . 22
8.2.6 Liquid receiver . 22
9 Test procedures . 23
9.1 General . 23
9.2 Calibration of the calorimeter room . 23
9.3 Measurement of the cooling capacity . 24
9.3.1 Air humidity . 24
9.3.2 Subcooled refrigerant temperature. 24
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9.3.3 Steady-state conditions . 24
9.3.4 Test duration . 24
9.3.5 Conducting the test . 25
9.3.6 Air inlet temperature . 26
9.3.7 Data to be recorded . 26
9.4 Measuring the fan performance . 26
10 Calculating the cooling capacity . 27
10.1 Heat loss factor . 27
10.2 Cooling capacity . 27
10.2.1 From the air side energy input . 27
10.2.2 From flow rate of refrigerant . 27
10.2.3 From the flow rate of liquid . 27
10.2.4 Measured capacity . 28
11 Conversion to standard conditions . 28
11.1 Cooling capacity . 28
11.1.1 General correction for atmospheric pressure . 28
11.1.2 Refrigerants with direct expansion operation . 28
11.1.3 Refrigerants - operation with liquid overfeed by pump circulation . 29
11.1.4 Liquids . 29
11.2 Calculating the standard liquid side pressure drop . 30
11.2.1 General . 30
11.2.2 Single Test . 30
11.2.3 Duplicate Tests . 30
11.3 Nominal air flow . 31
11.4 Nominal fan power . 31
12 Test report . 31
Annex A (informative) Bubble point temperature . 32
A.1 Diagram bubble point temperature . 32
Annex B (normative) Test installation for direct expansion operation . 33
Annex C (normative) Test installation for liquids . 35
Annex D (informative) Superheating and capacity . 36
Annex E (normative) Test arrangement . 37
Annex F (normative) Operation with liquid overfeed by pump circulation . 38
F.1 Scope . 38
F.2 Standard conditions . 38
F.3 Measurements . 39
F.4 Testing methods and equipment . 39
F.5 Test procedures . 40
F.6 Capacity calculations . 41
F.7 Conversion to standard conditions . 42
Annex G (informative) Procedure to measure the oil content . 45
Bibliography . 46
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SIST EN 328:2014
EN 328:2014 (E)
Foreword
This document (EN 328:2014) has been prepared by Technical Committee CEN/TC 110 “Heat exchangers”,
the secretariat of which is held by DIN.
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 2015, and conflicting national standards shall be withdrawn
at the latest by February 2015.
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.
This document supersedes EN 328:1999 and EN 328:1999/A1:2002.
The main changes with respect to the previous edition are listed below:
a) Clause 3 “Terms and definitions” is modified;
b) The revised standard takes into account the application of CO .
2
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, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
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EN 328:2014 (E)
Introduction
This European Standard is one of a series of European Standards dedicated to heat exchangers.
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EN 328:2014 (E)
1 Scope
This European Standard is applicable to non-ducted unit air coolers for refrigeration operating:
a) with direct dry expansion of a refrigerant;
b) with liquid overfeed by pump circulation of a refrigerant;
c) with a liquid.
This standard specifies uniform methods of performance assessment to test and ascertain the following:
— product identification;
— standard capacity;
— standard liquid pressure drop;
— standard refrigerant pressure drop (for operation with liquid overfeed by pump circulation only);
— nominal air flow rate;
— nominal fan power.
It does not cover evaluation of conformity.
It is not applicable to air coolers for duct mounting or with natural air convection.
This standard does not cover technical safety aspects.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC
17025)
EN 60034-1, Rotating electrical machines - Part 1: Rating and performance (IEC 60034-1)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1
physical definitions
3.1.1
forced convection unit air cooler
refrigeration system component transferring heat from air to a refrigerant or liquid. The air is mechanically
circulated over the heat transfer surface by integral fan(s) and fan drive(s)
Note 1 to entry: The heat transfer coil includes refrigerant distributing and collecting headers.
Note 2 to entry: In the following “forced convection unit air cooler” is referred to as “unit cooler”.
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3.1.2
heat transfer surface (air side)
external surface of the cooling coil which is in contact with the air flow passing the cooling coil
3.1.3
internal volume
volume of the refrigerant containing parts of the unit cooler between its two connections
3.1.4
fouling resistance
thermal resistance of a layer of unwanted deposit on the heat exchanger surface reducing its heat transfer
performance
Note 1 to entry: The fouling resistance for a clean surface is zero. Clean, in this context, means that all production
residues have been removed from the heat transfer surface and the fan(s) by the factory's cleaning process.
3.2
refrigerant
working fluid in a cooling system, which absorbs heat at low pressure / temperature by evaporation and
rejects heat at a higher pressure / temperature by condensation
3.3
liquid
working fluid remaining liquid during the absorption of heat
3.4
capacities
3.4.1
sensible air cooling capacity
heat flow rejected by the air resulting from a dry bulb temperature drop
3.4.2
latent cooling capacity
heat flow rejected by the air resulting from condensation of water vapour or frost formation including
subcooling on the unit cooler surface
3.4.3
total cooling capacity
sum of the sensible and the latent capacities measured at the same time
3.4.4
gross cooling capacity
total heat flow absorbed by the refrigerant or liquid
3.4.5
net cooling capacity
cooling capacity available for cooling the air equal to the gross cooling capacity minus the fan power
3.4.6
standard capacity
gross cooling capacity at standard conditions and normal atmospheric pressure of 1013,25 hPa of a unit
cooler with clean internal and external surfaces
3.4.7
fan power
electric power, absorbed by the fan motors at the electrical terminals of the motor(s)
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3.4.8
nominal fan power
fan power measured during the air flow test and corrected to the normal atmospheric pressure of 1013,25 hPa
Note 1 to entry: The fan power will also differ with the temperature at which the fan runs. As the fan power is only a
small proportion of the total cooling load, the deviations are considered to be negligible.
3.5
rotational speed of the fans
average rotational speeds of fans
3.6
pressures and pressure differences
for the purposes of this standard all pressures are average values ascertained over the test duration
3.6.1
evaporating pressure
absolute pressure of the refrigerant, at the outlet connection of the unit cooler
3.6.2
liquid inlet pressure
static pressure of the liquid at the inlet connection of the unit cooler
3.6.3
liquid outlet pressure
static pressure of the liquid at the outlet connection of the unit cooler
3.6.4
liquid pressure difference
difference between the liquid inlet pressure and the liquid outlet pressure
3.6.5
refrigerant inlet pressure
absolute pressure of the refrigerant, at the inlet connection of the unit cooler (see Annex F)
3.6.6
critical pressure
pressure at the critical point where the liquid and gaseous phases of the refrigerant have the same physical
properties
3.7
temperatures
for the purposes of this standard all temperatures are average values ascertained over the test duration
3.7.1
air temperatures
3.7.1.1
air inlet temperature
average dry bulb temperature of the air at the unit cooler inlet, taking into consideration the local air velocities
3.7.1.2
air dew point temperature
dew point temperature of the air within the calorimeter room
3.7.1.3
inside temperature
air temperature inside the calorimeter room responsible for the heat exchange with the ambient
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3.7.1.4
ambient temperature
temperature around the calorimeter room responsible for the heat exchange with the inside
3.7.2
refrigerant temperatures
3.7.2.1
evaporating temperature
dew point temperature of the refrigerant, corresponding to the evaporating pressure
3.7.2.2
superheating temperature
temperature of the refrigerant vapour at the outlet connection of the unit cooler, measured on the wall of the
tube at the location recommended by the manufacturer for fixing the expansion valve sensing element or
downstream of the liquid-suction heat exchanger where this is an integral part of the unit cooler
3.7.2.3
subcooled refrigerant temperature
temperature of the liquid refrigerant at the inlet connection to the expansion device (not necessarily part of the
unit cooler)
3.7.2.4
bubble point temperature for cooler measurement
temperature calculated from the enthalpy based on the temperature and pressure at the inlet of the expansion
valve
3.7.3
liquid temperatures
3.7.3.1
liquid inlet temperature
average temperature of the liquid at the inlet connection of the unit cooler taking into consideration the local
liquid velocities
3.7.3.2
liquid outlet temperature
average temperature of the liquid at the outlet connection of the unit cooler taking into consideration the local
liquid velocities
3.7.4
water temperatures
(applicable only where the balancing heat is supplied by water)
3.7.4.1
water inlet temperature
temperature of the water as it enters the calorimeter
3.7.4.2
water outlet temperature
temperature of the water as it leaves the calorimeter
3.7.5
vapour outlet temperature
temperature of the refrigerant vapour at the vapour outlet connection of the separator
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3.8
temperature differences
3.8.1
temperature differences for refrigerants
3.8.1.1
inlet temperature difference
difference between the air inlet temperature and the evaporating temperature
3.8.1.2
superheating
difference between the superheating temperature and the evaporating temperature
3.8.1.3
degree of superheating
ratio of the superheating to the inlet temperature difference
3.8.1.4
subcooling
difference between the bubble point temperature corresponding to the absolute pressure of the refrigerant at
the inlet connection to the expansion device and the subcooled refrigerant temperature
3.8.2
temperature differences for liquids
3.8.2.1
inlet temperature difference
difference between the air inlet temperature and the liquid inlet temperature
3.8.2.2
liquid temperature difference
difference between the liquid inlet and outlet temperatures
3.9
high glide
refrigerant where the difference between the condensing and bubble point temperatures at a condensing
temperature of 40 °C is greater than 3K
3.10
operation with refrigerants
3.10.1
direct expansion operation
evaporation process in which the refrigerant enters the unit cooler via a direct expansion device as a liquid-
vapour mixture and leaves it in superheated state (see system boundaries in Annex A)
3.10.2
operation with liquid overfeed by pump circulation
evaporation process in which the refrigerant leaves the unit cooler in partially evaporated state, the process
being operated by a mechanical liquid pump and a separator being parts of a refrigerating machine
Note 1 to entry: The refrigerant is transported from the separator to the unit cooler by the mechanical pump (see
Annex F).
3.10.3
supercritical operation
thermodynamic cycle in which the outlet pressure at the compressor is higher than the critical pressure of the
refrigerant with a gas cooler being part of the refrigerator
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3.11
refrigerant enthalpies
3.11.1
refrigerant inlet specific enthalpy
specific enthalpy of the refrigerant at the inlet connection of the unit cooler system. For capacity calculation it
is defined as the specific enthalpy of the saturated liquid refrigerant at the inlet to the expansion device
corresponding to the subcooled refrigerant temperature and for transcritical operation it is defined as the
enthalpy corresponding to temperature and pressure
Note 1 to entry: For liquid overfeed by pump circulation the refrigerant inlet enthalpy cannot be defined by temperature
and pressure measurement at the unit cooler's connections (see Annex E).
3.11.2
refrigerant outlet specific enthalpy
specific enthalpy of the refrigerant at the outlet connection of the unit cooler system. For capacity calculation it
is defined as the specific enthalpy of the refrigerant corresponding to the evaporating pressure and the
superheating temperature
Note 1 to entry: For liquid overfeed by pump circulation the refrigerant outlet enthalpy cannot be defined by
temperature and pressure measurement at the unit cooler's connections (see Annex E).
3.11.3
specific vaporization enthalpy
enthalpy at the evaporating pressure without regard to the pressure drop across the unit cooler (see Annex F)
3.12
nominal air flow
air volume flow rate flowing through the unit cooler, when its air side is dry and clean
3.13
oil content
proportion of oil by mass in the refrigerant related to the pure refrigerant
3.14
refrigerant recirculation rate
ratio between the actual mass flow rate through the unit cooler and the mass flow rate necessary for the total
evaporation of the refrigerant (see Annex F)
4 Symbols
For the purposes of this document, Table 1 applies:
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EN 328:2014 (E)
Table 1 — Symbols
E kJ
electrical energy input into the calorimeter
el
F correction factor for the deviation fr
...
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