How Does an Enclosure Cooling Unit Work?

Electrical cabinets house components such as PLCs, drives, power supplies, and controllers that generate heat during operation. As the internal temperature rises, excessive heat can affect component reliability, shorten service life, and lead to unwanted downtime.
An enclosure cooling unit, also called an electrical cabinet air conditioner or panel chiller, provides a dedicated way to remove this heat. Unlike a ventilation fan that brings ambient air into the cabinet, a closed-loop cabinet cooling unit circulates the cabinet air through a refrigeration system while keeping it separated from the surrounding environment.

How Does an Electrical Cabinet Cooling Unit Work?
The cooling process involves two separate air circuits: internal cabinet air circulation and ambient air circulation.
1. Hot Cabinet Air Passes Through the Evaporator
The internal fan draws hot air from the electrical cabinet into the enclosure cooling unit. The air passes over the evaporator, where the refrigerant absorbs heat from the cabinet air.
The cooled air is then returned to the cabinet. This continuous circulation helps maintain a more stable internal temperature.

2. The Refrigeration Cycle Removes the Heat
At the same time, the refrigerant carries the absorbed heat through the refrigeration circuit: Evaporator → Compressor → Condenser → Expansion Device → Evaporator.
After absorbing heat in the evaporator, the refrigerant enters the compressor, where its pressure and temperature increase. It then flows through the condenser, where an external fan moves ambient air across the condenser to release the heat outside the cabinet.
After passing through the expansion device, the refrigerant returns to the evaporator at a lower pressure and temperature, ready to absorb heat again.
This cycle repeats continuously while cooling is required.

Why Does a Cabinet Air Conditioner Use Separate Air Circuits?
The internal and external airflows remain separated. The cabinet air is recirculated through the evaporator, while ambient air is used to cool the condenser.
This closed-loop design is particularly useful in industrial environments where bringing untreated ambient air into the enclosure could introduce dust, moisture, or other contaminants.
For CNC machines, laser equipment, automation systems, and other industrial controls, maintaining a more controlled cabinet environment can help protect sensitive electronics during long operating cycles.

What Happens to Condensation?
When the evaporator surface temperature is below the dew point of the cabinet air, moisture may condense on the evaporator. The condensate is collected in the water pan and should be properly managed according to the cooling unit design and installation conditions.
For this reason, enclosure sealing, ambient conditions, cabinet heat load, and operating temperature all matter when selecting and installing a cabinet cooling unit.

TEYU ECU Enclosure Cooling Units
TEYU ECU enclosure cooling units are designed for thermal management of electrical cabinets and industrial enclosures. TEYU ECU series includes TEYU ECU-300, TEYU ECU-800, TEYU ECU-1200, and TEYU ECU-2500, providing 300W to 2500W cooling capacity for applications including electrical control cabinets, CNC systems, laser equipment, and industrial automation.
Selecting the right electrical cabinet air conditioner should be based on the actual heat load, ambient temperature, enclosure conditions, and required internal temperature—not simply cabinet size.
With the right cooling capacity and proper installation, a closed-loop enclosure cooling unit provides a practical way to keep electrical cabinets cooler and maintain more stable operating conditions for the electronics inside.