IEC TS 62610-2:2011 pdf – Mechanical structures for electronic equipment -Thermal management forcabinets in accordance with IEC 60297 and lEC 60917 series – Part 2: Design guide: Method for the determination of forced air-coolingstructure.
This part of IEC 62610 provides for compatible methods of forced air cooled cabinets assembled with associated subracks and/or chassis In accordance with the IEC 60297 and IEC 60917 saries
This design guide contains the following:
a) Thermal interfaces of subrack and/or chassis based equipment in a cabinet
• Reference temperature
• Preferred airflow conditions
• Airflow volume conditions
• Standard air
b) Procedures for determining compatible forced airflow conditions in a cabinet by appiying
typical thermal interface conditions
The drawings used are not Intended to indicate product design. They are only explanatory indications for determining forced air-cooling structure.
The terminology used complies with IEC 60917.1.
2 Thermal interfaces
2.1 Baseline thermal conditions
In order to enable reproducible and comparable values, standard air is defined at the air inlet to be used for the determination of the thermal capability and requirement parameters of products.
NOTE Standard air as defined for this purpose has a d.nsdy 04 1.2 kglmt. a reiatàve humidity 04 50%. a temperature of 20 C. a ptessure of 1.013 s 10 Pa A specified heal capacity is 1 005 J/ligk at these conditions. These values are aligned with the fan iisdustrV spec*flcahons, common test practices and electrornc industry expectations
2.2 Reference temperature
The thermal operating temperature of subrack and chassis in the cabinet should be defined at the air Inlet. and this temperature Is called reference temperature In this technical specification.
Reference temperature is defined as the temperature of an objective ambient air of the equipment in the cabinet which is a starting point for a rise in internal temperatures of the equipment, and, at the same time, Influences internal temperatures of 1t
At one typical equipment which consists of a subrack and a forced air-cooling device. temperatures of internal air and inside components of the subrack are determined as certain values from reference temperature And. reference temperature” of the equipment cabinet can be considered as equivalent with its intake air temperature, because the heat dissipating path of the forced air.cooling is dependent on ventilation characteristics of the equipment. (see Clause A.2)
The air intake is the initial point of an upstream airflow wtiere air flows into the equipment to cool its inside, The intake air temperature of the equipment (T3-nr) as supplied by the ambient temperature (T4) could be identical (see Figure 6).
NOTE GenerCily, Ih. intake air temperature is measured at the positions from 30 mm to 50 mm away from the outline ot the equipment to avoId the Influence 04 heat radiation At the air Intake opening. if the temperature Is not considered as homogeneous because th, opening is so wide several positIons (3 to 5) should be d,lin.d as reference temperature positions, and the average temperature should be taken as the intake air temperature.
2.3 Syntax of surfaces of a generic subrack, chassis or cabinet
In order to define airflow patterns of subrack and/or chassis based equipment mounted within a cabinet the syntax of the outer surfaces Is defined as In Figure 1.
2.4 Preferred airflow conditions
In order to facilitate an efficient cabinet airflow design，it is necessary to define the preferredairflow pattern of the cabinet mounted equipment. lt is important that the cold air entry is notcontaminated by the hot air exit (separation of the air entry path and the air exit path). Theessential principles of cooling airflow direction are “FRONT to REAR” and “BOTTOM to TOP”.
The complete syntax of airflow pattern in Table 1 is as follows :
Intake definition [+ additional intake definition] → exhaust definition [+ additional exhaustdefinition]
The intake and exhaust definition corresponds to the syntax of the surfaces as shown inFigure 1 and Figure 2.