Pfannenberg cooling units operate on the principle of the Carnot cycle. This means that the cooling units function as a heat pump that “pumps” the thermal energy transferred from the electronic cabinet (heat dissipated from the components) up to a higher level of temperature (the ambient temperature can reach levels as high as + 55 °C). The air inside the enclosure is cooled down by the evaporator and at the same time dehumidified.
How do I know if a cooling unit is the right product for my application?
- If the ambient temperature is greater than the target internal temperature of the enclosure, active cooling is required.
- If indoor NEMA Type 12 applications, NEMA Type 3R/4 outdoor applications and NEMA Type 4/4x stainless steel for washdown applications are required – closed loop cooling can maintain the NEMA Type rating of the cabinet.
Properly sizing a cooling unit
Utilizing performance curves to properly size cooling units:
> Pfannenberg utilizes the DIN standard 35/35 °C when rating our cooling units.
> Many other companies use 50/50 °C, which provides a higher, non-usable value. Customers should use their own application temperatures to determine the proper cooling capacity of the system.
Important information when utilizing cooling units:
- The refrigeration capacity should exceed the dissipation loss from the installed components by approximately 10%.
- The enclosure should be sealed to prevent the inflow of ambient air.
- Use the door contact switch to impede operation with open doors and consequent excessive accumulation of condensation.
- Use cooling units with maximum clearance between air inflow and air outflow to prevent poor circulation.
- Make sure that the air inflow and air outflow in the external circuit is not hindered, preventing proper heat exchanging at the condenser.
- When using top-mounted cooling units, make sure that components with their own fans do not expel the air directly into the cooling units cool air outflow.
- Make sure unit is level.
- Setting the temperature to the lowest setting is not the optimal solution due to the condensation issues. The value we have preset on the cooling unit is a sound compromise between cooling the inside of the enclosure and the accumulation of condensation.
In harsh environments involving high temperatures, wash-down requirements, heavy particulate matter or the presence of chemicals capable of damaging components (NEMA 4 or 12 environments), ambient air must be kept out of the enclosure. Pfannenberg Cooling Units seals out the ambient air, cooling and re-circulating clean, cool air throughout the enclosure.
Pfannenberg offers Critical Thermal Management Solutions for Maximum uptime and efficiency.
Find the previous articles of this “Technology of Cooling” serie: Cooling with Closed Loop Air to Air Heat Exchangers.and