Outdoor enclosure cooling
from ventilation to heat pump

Outdoors, thermal management is a must, not an accessory

At ZPAS, outdoor climate control is the thermal management for outdoor cabinets (IP54/IP55) and comprises forced ventilation with a ventilation panel, dual air circulation, cross-flow heat exchangers, CVO cooling units (550–5,800 W) and the reversible AHP heat pump — sized to IEC 60890 plus solar load, mounted and wired ex works. An outdoor cabinet works between two extremes: in summer the sun heats the cabinet on top of the power loss of the equipment; in winter there is a risk of frost and condensation, against which a thermostat-controlled enclosure heater protects. The double-walled SZD design, with its ventilated double wall, takes care of the solar load — for everything else there are four graded ways of dissipating heat, from the ventilation panel to the heat pump. Which one fits depends on the heat load, the location and one question: may it be warmer inside than outside? All options are available for the IP54 standard cabinets as well as for the IP55 outdoor enclosure — with a heat exchanger or cooling unit, the degree of protection is fully maintained thanks to the closed circuit.

The four ways — and the heat pump

WAY 1 · VENTILATION

Way 1: forced ventilation with a ventilation panel

For moderate heat loads, ventilation panels accelerate air circulation in the cabinet and in the enclosure shell. For cold nights, an air heater (400 W) works with a thermostat — so the equipment stays within the permissible window even in winter. This is the most economical stage: no refrigeration technology, hardly any maintenance.

📄 In the catalogue: pp. 16–17 →

WAY 2 · SOLAR LOAD

Way 2: dual air circulation in full sun

If the cabinet is exposed to the sun, an external air circuit flows between the double walls of the door and side panels and carries away the solar heat — assisted by roof fans. The internal circuit cools the devices but remains completely separate from the outside air: dust and moisture do not reach the electronics.

📄 In the catalogue: p. 17 →

WAY 3 · HIGH HEAT LOAD

Way 3: cross-flow heat exchanger and direct ventilation

With a high heat load, the cross-flow heat exchanger takes over: warm internal air and cool outside air flow separately through a radiator — the heat changes sides, while the air flows do not mix by design. If even more heat has to be removed (typically with UPS installations), direct ventilation comes into play: two fans of 510 m³/h each draw outside air through the double wall and filters.

📄 In the catalogue: pp. 18–19 →

WAY 4 · ACTIVE COOLING

Way 4: cooling unit — when it has to be cooler inside

Only when the internal temperature has to be below the outside temperature is active cooling required: CVO series compressor cooling units (550–5,800 W). Mounting depends on space and maintenance concept: inside the cabinet, recessed in the door or on the outside of the enclosure — internally mounted units sit on the door or on hinged side covers so that maintenance remains easy.

📄 In the catalogue: pp. 20–21 →

AHP · COOLING + HEATING

The premier class: the reversible AHP air heat pump

The AHP_35_Ti cools and heats with one unit — controlled by temperature and humidity measurement in the cabinet: 10–40 °C and 32–72 % relative humidity kept constant all year round, maintenance-free and more economical than a cooling unit plus electric heater. For larger loads: AHP 7.0 (7 kW cooling / 9 kW heating, −15 to +50 °C, IP 55).

📄 In the catalogue: pp. 22–24 →

Which way for which case?

Sizing follows IEC 60890 plus solar load — fastest with the cooling & heating capacity calculator. Delivery is complete: unit sized, mounted and wired ex works, thermostat and heater included if the site requires them — both in detail on the outdoor cabinet accessories page.