Electrical control cabinets, telecom cabinets, and variable-frequency cabinets contain PLCs, servos, and frequency converters that generate continuous heat during operation. For every 10°C rise in temperature, the failure rate of electronic components roughly doubles; above 40°C, the fault rate rises significantly. Therefore, the first principle of cabinet air conditioner sizing is not "the bigger the better," but "the cooling capacity should just cover the total heat load with a 20% margin."
1. Cooling Capacity Formula
The heat a cabinet air conditioner must remove comes from four parts; the total cooling capacity is:
Q_total = Q_internal + Q_solar + Q_conduction + Q_convection
- Q_internal: total heat dissipation power (W) of in-cabinet equipment, taken as the sum of nameplate power consumption;
- Q_solar: heat gain from direct solar radiation on the cabinet surface; must be counted for outdoor/near-window scenarios, approx. 200-400W;
- Q_conduction: heat conducted through the cabinet wall due to inside-outside temperature difference, approx. 100-300W (related to cabinet area and insulation);
- Q_convection: heat brought in by convection from surrounding high-temperature air, approx. 100-200W.
2. Sizing Example
For an electrical control cabinet: in-cabinet equipment dissipates 2400W, with high ambient temperature and solar + conduction combined approx. 600W, so Q_total ≈ 3000W. With a 20% margin, choose the 3000W model; if heat reaches above 4000W, choose 5000W; 7500W is for high-power variable-frequency cabinets or combined cabinets.
3. Typical Scenario Comparison Table
| Scenario | Typical Heat | Recommended Cooling Capacity | Key Requirements |
|---|---|---|---|
| General electrical control cabinet | 2000-2800W | 3000W | IP55, wall-mounted |
| Telecom base station / server room cabinet | 2500-3500W | 3500W | low noise, stable |
| Variable-frequency cabinet / high-power drive | 4000-6000W | 5000W | wide temperature, strong heat dissipation |
| Combined cabinet / outdoor high-power | 6000W+ | 7500W | IP55, outdoor |
4. Sizing Key Points
- First calculate Q_internal (sum of equipment nameplate power), then add environmental heat gain;
- For high-temperature, outdoor, and coastal scenarios, always choose IP55 protection;
- Reserve a 20% margin to avoid long-term full-load operation of the compressor;
- Non-standard cabinets, explosion-proof, 48V DC, etc. can be customized.
Go back to the HCK cabinet air conditioner product page to view full-range model specifications from 3000-7500W, or contact Haocheng Industrial Control for a one-on-one sizing solution.