An enclosure that traps heat will kill a heat pump. Compressors, inverters and control boards generate substantial heat, and outdoor summer temperatures add to the load. Thermal management is therefore not an afterthought — it is a core design discipline for every sheet metal enclosure we build.
Where the Heat Comes From
Three sources matter. The compressor itself radiates heat. The electrical compartment (inverter, PCB, capacitors) generates heat that must stay below roughly 60–70°C for component lifetime. And solar radiation on dark panels can push skin temperature 15–20°C above ambient. Your enclosure design must handle the sum of these.
Passive Cooling First: Louvers and Perforation
Before adding fans, optimize passive airflow. Louvers pressed into the lower and upper panels create a natural chimney effect — cool air enters low, warm air exits high. Key parameters:
- Perforation ratio: typically 30–50% of the panel area for adequate free airflow.
- Louver pitch and angle: 45° angled louvers block rain while allowing air; tighter pitch blocks more water but restricts flow.
- Placement: inlet low on one side, outlet high on the opposite side, so air crosses the hot components.
Active Cooling: Fans and Cutouts
When natural convection is insufficient, add axial fans. Fan cutouts in the enclosure must be CNC-cut to the exact fan frame profile, with the flange formed inward or outward depending on flow direction. Remember to account for filter and finger-guard thickness in the cutout depth.
Testing Before Tooling
We recommend thermal simulation or a simple prototype test: run the unit at rated load in a 35°C chamber and log internal temperatures with thermocouples. The data tells you whether the louver area and fan selection are adequate — long before you commit to production tooling.
Fulei Metal provides DFM feedback on every enclosure drawing, including airflow and louver recommendations. Contact our engineers with your heat load figures and we will help you size the openings correctly.