Within this catalog, heat sinks are organized based on their shape and dimensions expressed in millimeters. Each profile is characterized by the following parameters:

• Weight: expressed in kilograms per meter of profile length (Kg/m).
• Length: indicated in millimeters and used for calculating thermal resistance (L).
• Width: also in millimeters, considered for calculating thermal resistance (°C/W), applicable only to high-efficiency heat sinks.
• Thermal Resistance in Natural Convection: expressed in °C/W with a temperature difference of 70°C (compared to an ambient temperature of 25°C).
• Thermal Resistance in Forced Convection: also expressed in °C/W, with an air velocity of 3 m/s and a temperature difference of 50°C.

The values of thermal resistance have been determined through a thermal simulation program designed to replicate realistic conditions. In particular:

• The heat source is uniformly distributed over approximately 50% of the dissipation surface, with central positioning on the heat sink.
• To maximize natural convection heat dissipation efficiency, the heat sink is designed with vertical fins. For horizontal installations, it is advisable to consider an increase of approximately 20% in thermal resistance.
• The surface of the heat sink is not subject to additional treatments.

Regarding black anodized heat sinks in natural convection, the thermal resistance is reduced by approximately 10%.

As the length of the heat sink increases, the thermal resistance decreases following a nonlinear law. The indicated values refer to the specified lengths; for different lengths, consult the “Length Correction Factor” graph to calculate the multiplication factor to be applied to the thermal resistance, both in natural and forced convection.