DIN EN 327:2014 pdf free.Heat exchangers—Forced convection air cooled refrigerant condensers—Test procedures for establishing performance.
5 Standard capacity
5.1 Basis for standard capacity data
The influence of the refrigerant mass flow, the heat flux and the condensing temperature on the overall heat transfer of an air cooled condenser is low. As a result, in the range of temperature differences between 10 K and 20 K, the capacity is almost proportional to the temperature difference. The influence of superheat on the capacity is also low; it is below + 0,5 % per K superheat.
For refrigerants which are cooled but not condensed in the gas cooler the test conditions shall be observed with the greatest possible accuracy, as conversion to standard conditions can be very extensive.
The airflow through a condenser/gas cooler has great influence on its capacity. Because of the complicated relations a simple conversion to other air flows is not possible with sufficient accuracy. Therefore the electrical values which influence the fan speed (voltage and frequency) shall correspond with the standard supply conditions.
5.2 Standard capacity conditions
The standard capacity shall be based on tests performed on a clean and dry condenser/gas cooler under the following operating conditions:For all other refrigerants this shall be related to superheating that results when the refrigerant is subjected to isentropic compression from – 10 °C evaporating temperature at + 10 °C superheated vapour temperature to + 40 °C condensing temperature.
5.3 Conditions for the nominal air flow rate The nominal air volume flow rate refers to an air temperature of + 20 °C and an atmospheric pressure of 1 013,25 hPa. NOTE 1 For refrigerant R744 (CO2) the optimal high pressure has been taken as the basis for determining the gas cooler inlet temperature. NOTE 2 The air volume flow is not influenced by atmospheric pressure and temperature if the fan speed is constant.
5.4 Conditions for nominal fan power The nominal fan power refers to an air temperature of + 20。C and to an atmospheric pressure of 1 013,25 hPa.DIN EN 327 pdf download.