Passive shelter, semi-passive shelter, active shelter

Equipment housing with walk-in facilty.

This infrastructure, used to house any kind of equipment, represents Celantel’s Core Business which includes: shelters, containers, cabinets, racks and other special items.

Celantel, in particular, provides all the possible housing solutions, from the traditionals with active conditioning, to the “patented” passive ones or as well to those with different hybrid solutions including active / passive or simple ventilated typology.

The passive self-conditioning shelter is certainly Celantel’s best product offered to the Market.

The idea of passive shelter comes from Celantel and represents the basic principle of a series of industrial patents which boasts attempts at imitation, adequately defended and protected.

The one of 2002, in particular, is based on the principle of day/night heat exchange of the heat produced by the equipment and accumulated in adequate thermal capacities during the day that is, subsequently, disposed of externally during the night.


In manufacturing this, with innovative solutions and improvements, Celantel’s aim was to increase the overall thermodynamic efficiency, always respecting the original principles as regards to the absence of maintenance, energy-saving etc.

The Passive shelter

When the air conditioning does not depend on the energy supply – ZERO ENERGY

It is characterized by:

  • Watertight internal room.
  • Absence of moving mechanical parts.
  • Absence of pressurized fluids.
  • Hydraulic circuit perfectly sealed (watertight).

The related application concerns remote stations, or any requiring no maintenance.

Operating criteria – The Thermal Diode and the Thermal Condenser

In order to make the air conditioning independent from any energy source, it is unavoidable to draw the energy made available by the environmental climatic conditions.

The passive system uses the thermal energy of the night, moving it and collecting it inside and then releasing it for 24 hours.

Celantel’s patented device has two peculiarities: it is perfectly sealed so that it doesn’t need any replacement during the operational stage and it is modular type.  A fluid is employed as thermal vector and as store function.
Each passive shelter is divided into:

  • Tank/Internal heat exchanger.
  • External heat exchanger.

The first one controls the internal thermal energy and, thanks to an adequate accordion shape and a functional position to the thermal flows, allows the expected heat absorption. In some circumstances, the store function is integrated with the addition of specific products, e.g. phase transition materials (PCM).
The second, therefore, is typically on the top of the shelter or closet, so that it is easily cleaned and is configured to maximise heat exchange through conduction to the environment and through radiation to outer space, introducing in this way a sub effect of night cooling.

The passively cooled shelter follows the operational procedures of a diode (thermal), allowing the internal heat transfer towards the external and not vice versa.

thermal en
    The heat generated by the internal systems, added up to the contribution givenby the environmental stress, is accumulated in the tank through the internal tank/exchanger,thus,  warming the liquid stored inside.
    The fluid inside the external exchanger cools down starting the circulation process in the closed circuit (natural convention) till its complete regeneration.

Project Criteria

The calculation method is essentially based on the difference between the minimum external night temperature and the maximum inside temperature, allowed by the electronic devices.

This calculation uses a complex algorithm developed by Celantel.

It could depend on: specific temperatures of the places taken into consideration, certified by the global databases, or project requirements and it allows an accurate evaluation of all the manufacturing parameters of the passively cooled shelter, providing the graphics of the performance expectations.

Project Criteria
SHELTER PASSIVE Biggest PCS  in the world
SHELTER PASSIVE Middle East installation
SHELTER PASSIVE Shelter in remote area
SHELTER manufacuring

The semi-passive shelter

When the air conditioning partially depends on the energy supply – ENERGY SAVING-
The related application refers to high heat dissipation stations, including all the passive shelter features and ensuring a limited energy consumption and maintenance.  There are three subcategories of product, suitable for fixed or mobile stations.

semi passive shelter en 1

High capacity Semipassive

This system is derived from the passive shelter with water circulation, facilitated by a pump and an internal or external forced ventilation so to increase the heat exchange, allowing as well high heat dissipations and, finally, maintaining features such as: low maintenance and consumption.


Passive cooling system supported by an auxiliary air conditioner or chiller, activated only during the warmer months of the year.

semi passive shelter en 2
semi passive shelter en 3

Three-way Semipassive

Made up of a three-way heat exchanger, it is equipped with storage and forced ventilation. It ensures the temperature control with a low power consumption. This compact size module allows an optimization of the internal spaces of the shelter and the possible installation on the existing units, already at site, so to replace the traditional air conditioning.

SHELTER   SEMI PASSIVE   Hybrid shelter for ARAMCO

The active shelter

When the air conditioning uses electrically activated systems and/or devices in order to allow the air inlet / outlet.


  • Temperature management fully controlled by air conditioning.
  • Ventilation with direct air input.
  • Possible split units installation, integrated or roof type.

Manufactured with unframed composite panels shelter body (Fiberglass or Aluminum) or with framed container type steel structures.

active shelter en

Shelter structure

There are two different kind of housings:

  • Cabinet (with direct access to the equipment without a “walk-in facility”).
  • Shelter (with “walk-in facility” internal access).

Construction technology
The Shelter or cabinet body consists of an original structure, without metal frame, always composed of six monolithic multilayer panels, created through a pressing and temperature controlled process.
Each panel has two external Glass Fiber Reinforced Plastic (GRP) or Metal “skins” and an extruded panels heart of expanded polystyrene or mineral wool.

Constructive qualities

  • Easy and fast to be repaired.
  • Total lack of welding.
  • No GRP painting (gel coat).
  • No maintenance. Packaging for shipments by sea not necessary.
  • No solar panel is necessary.
  • Suitable for installations in desert or arctic areas.
frp en

Technical features:

  • Resistant to corrosion and acids attack (GRP).
  • Highly accurate thermal insulation.
  • Absence of thermal bridges and condensation areas.
  • IP65 or IP66 protection.
  • Resistance to fire from the M2 to the REI120 class.
  • Temperature application from -50°C to + 60°C.
  • Very high intrinsic electrical insulation of the all structure with the use of dielectric materials.
  • Integrated metal reinforcements for the equipment fixing on the walls.
  • Roof load 500 kg/m2 and pressure resistance of the walls (pressure test up to 160 kg/m2).
  • Scratching resistance and dent resistance ASTM D 256.
  • No protrusion, absence of screws, rivets or junction metal elements.
  • Possible openings with no position or width limits.