Heat Dissipation Design: A Five-Step Approach
The heat dissipation design for power distribution cabinets involves five steps: heat generation calculation → natural heat dissipation (ventilation) → forced heat dissipation (fans/air conditioning) → heat source layout → temperature rise verification.
Industry experts note that the design process follows this sequence: calculating heat generation (component losses/total heat output), natural dissipation (vents/louvers), forced dissipation (fans/AC based on thermal load), heat source layout (dispersing heat sources/air vent placement), and temperature rise verification (testing/simulation).
The design must comply with the temperature rise requirements of the GB/T 7251 standard to prevent excessive temperature rise.
Five-Step Approach
- Heat generation calculation: Component losses (thermal load of circuit breakers/transformers), total heat output;
- Natural heat dissipation: Vents/louvers (natural convection), suitable for low-power cabinets;
- Forced heat dissipation: Fans (axial/exhaust) or air conditioning (for high thermal loads), configured as needed;
- Heat source layout: Dispersing heat sources (uniform dissipation) and optimizing air vent design (e.g., bottom-in/top-out airflow);
- Temperature rise verification: Testing/simulation (verifying levels are ≤ permissible limits) and refinement.
Key Design Points
First, calculate heat generation.
Determine heat output (component losses) to select the appropriate dissipation method.
Second, match dissipation to needs.
Choose natural dissipation (low power) or forced dissipation (high power) based on the thermal load.
Third, optimize the layout.
Disperse heat sources and design air vents to ensure uniform heat dissipation and prevent hotspots.
Fourth, verify temperature rise.
Conduct temperature rise tests (ensuring the rise is ≤ the permissible limit of 70K) to confirm compliance.
Pitfalls to Avoid
First, underestimating heat generation (resulting in excessive temperature rise);
ensure accurate calculations.
Second, insufficient heat dissipation (causing hotspots);
configure cooling components according to requirements.
Third, concentrated layout (leading to localized overheating);
adopt a distributed layout.
Trends and Recommendations
Thermal management is moving towards “intelligence”: smart temperature control (variable-speed fans) and digital simulation (thermal simulation) enhance efficiency.
Designers are advised to follow a “five-step approach”: calculate heat generation and verify temperature rise.
Effective thermal design ensures stable internal cabinet temperatures.
