DIN EN 328-2014-11 Heat exchangers – Forced convection unit air coolers for refrigeration – Test procedures for establishing the performance; English version EN 328:2014, English translation of DIN EN 328:2014-11.
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”.
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).DIN EN 328 pdf download.