HIREF is Europe's leading manufacturer of air conditioning and ventilation equipment, successfully operating in this field for more than 50 years. The company offers a wide range of equipment for use in the residential and commercial sectors.

Equipment quality is an integral part of this company’s strategy. This company was one of the first to be awarded a Eurovent certificate (1994). During production, all equipment is thoroughly inspected and tested, which ensures reliable service life of the equipment for a long time.

HIREF is a well-known manufacturer of precision air conditioning equipment, headquartered and headquartered in TRIBANO, Italy.


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HIREF offers a complete and integrated range of centralized precision control air conditioners for commercial and industrial buildings. The abundance of products creates added value and allows to take into account the needs of the market and individual customers. From precise control air conditioners to the most sophisticated refrigeration equipment, HIREF's experience and professionalism can guarantee customers products of the highest standards, attention to detail, the best COP levels, low-noise equipment: the guarantee of the ideal microclimate from HIREF. A wide selection of water refrigeration equipment and heat pumps from 5 to 1500 kW is an essential part of HIREF products.


Proves that all products at the HIREF factory are manufactured in accordance with European Union directives and regulations.


Certificate for compressed liquids, certifies suitable products, in the case of HIREF, refrigeration and hydraulic circuits in equipment with compressors.


EN ISO 9001:2000


Italian manufacturer HIREF Galletti Group precision control air conditioners are special devices that differ significantly in their operation from ordinary air conditioners.

Appliance capacities vary depending on the type and configuration of the appliance cooling. For example, the power of precision-controlled freon air conditioners (direct expantion) in both the up-flow air and down-flow air discharge versions ranges from 7 to 90 kW. The power of water-cooled precision-controlled air conditioners can reach up to 200 kW.

HIREF precision control devices are extremely energy efficient in all operating modes. Efficient operation not only reduces carbon emissions, but also minimizes operating costs. Although these devices are designed to work in data and communication centers, they are also well-suited for other institutions, such as various laboratories, museums, television studios, various control rooms, and all other rooms that emit extremely large amounts of excess heat and are not constantly filled with people.

Precision control devices manufactured by HIREF are also installed in various industrial facilities: optics, electronics, medical device production workshops, musical instrument workshops, etc. Depending on the design parameters, fresh air supply is also possible in these facilities.

High cooling capacity per 1m2 area values

This is a very important feature, especially in small rooms where many devices are to be installed, so it is crucial that the precision control device takes up as little space as possible, while allowing for more efficient use of the space. HIREF precision control air conditioners have been designed to extract as much power as possible while taking up as little space as possible. This is very important because as the equipment develops, heat emissions in the room increase, so more and more powerful precision control devices are needed.

As the settings of the devices decreased, the sound level did not increase. The main determinants are:

  • Extremely quiet scroll / DC inverter type compressors are installed;
  • Installing silent fans;
  • Additional sound insulation is installed in the housing elements.

Two main construction methods

  • Freon;
  • Water.

Using the properties of both refrigerants, precision control devices can be successfully adapted to work in both data centers and administrative or scientific facilities. Traditionally, freon devices are used in medium / small objects, where the need for cold power does not exceed 400 kW. Meanwhile, water precision control devices are used for higher cold demand.

The fan section is equipped with one or more centrifugal freewheels and backward curved blades (these fans are also called Plug fan type fans). This type of fan has a particularly quiet operation, and this type of fan has extremely easy access to the blades, so there are never any problems in cleaning the appliance. These fans are fitted with EC (electronically commutated) type motors as standard, which are manufactured using state-of-the-art technology to ensure minimum energy consumption.

EC motors are 25-30% more efficient than asynchronous motors installed in analog devices. These motors also allow the microprocessor to fine-tune the speed depending on the readings of the external sensors. This eliminates the need for frequency converters or other electronic devices. Working together, Plug fan-type fans and EC-type motors perform incomparably better under the same operating conditions than conventional equipment installed in this type of devices: increased device functionality, reduced noise level, vibration, as well as the introduction of a soft-starter function, which using significantly less energy during start-up of the air conditioner.

Four different airflow control methods are available for HIREF products:

• Constant microprocessor control of the fan speed. Selecting this control method ensures the high static pressure that is usually required in most objects. The resistance of the installed system causes a pressure drop, so to ensure the efficient operation of the entire system, it is necessary to accurately calculate the pressure loss, which is accurately estimated in the computer program "HIREF" selection.

• Constant air flow regardless of pressure drop in the filters. With the help of sensors installed inside the precision control device, the microprocessor controller changes the flow of air supplied to the fans depending on the contamination of the filters (in the case of contaminated filters, the pressure increases), thus ensuring a constant air flow. This control method ensures that unnecessary cooling, which occurs when the air flow into the room is reduced due to dirty filters, is avoided. The manufacturers recommend that this method of adjustment be used when the device uses F7 filters, thus ensuring a longer service life.

• Variable airflow control depending on cooling capacity. This is a typical variable airflow system that operates in response to increased heat release in the room to supply more cool air and conversely, when heat release decreases, the supply air decreases. It is understood that this method of regulation helps to save energy, especially when the control device is operating at low capacity. The variable airflow control method is only recommended for water-cooled precision air conditioners.

• Air flow control according to the pressure in the "artificial floor". This is a method of regulation that can only be applied to facilities with "artificial floors" that supply cool air to excess heat release zones. The microprocessor maintains a constant pressure under the floor based on sensor readings. For example, in very large rooms, the whole area can be divided into several zones, enclosing the space under the "artificial floor" with partitions so that air is supplied exactly where it is needed. The air supply to the excess heat release zone in this case is controlled by valves with electronic actuators and thermostats. Maintaining a constant air pressure is necessary to avoid an unbalanced air supply. In this case, it is also important to maintain the required fan speed, because the unexpected closing of one of the valves would significantly increase the air flow to the areas where air enters. Pressure sensors are installed at various points under the artificial floor, their readings are processed by a microprocessor, which in turn regulates the fan speed and thus ensures a constant pressure.

Fans with EC type motors HIREF precision control devices are installed as standard, but cheaper fans with AC type motors can be installed at the customer's request. These fans do not have a precise speed control and can operate at two different speeds, it goes without saying that in this case the air can only be supplied in two different modes.


HIREF precision control air conditioners are equipped with microprocessors adapted to control devices operating in data centers and various administrative buildings. These microprocessors operate by processing various signals from sensors installed at characteristic points in cooled rooms. Their operation ensures the main operating modes of precision control air conditioners: cooling without dehumidification, heating, humidification, regulation of the air flow into the room according to the contamination of the filters (or other control methods described above). The devices controlled by these processors work extremely efficiently. This not only saves energy, but also ensures the continuous operation of precision-controlled air conditioners, even in unforeseen / unexpected situations (such as failures of individual components).

HIREF's precision-controlled freon air conditioners are equipped with scroll-type air conditioners with extremely quiet operation and high energy efficiency. These compressors also use significantly less energy, thus saving operating costs and protecting the environment. Tests have shown that scroll compressors provide better operating conditions than other types of compressors at the same operating parameters. The design of these compressors avoids the installation of additional valves, which cause significant pressure losses in conventional compressors. This increases the energy efficiency of the compressors. For all precision control air conditioners in this series, only the most efficient and reliable compressors are selected from world-renowned companies.

Electronic expansion valves are one of the latest devices used in freon cooling systems, which helps to reduce energy consumption when the unit is operating at part capacity. These valves are mounted at the inlet to the evaporator. They replace the thermostatic expansion valves most commonly used in this type of device. Electronic valves allow much more precise control of the amount of refrigerant entering the evaporator. The adjustment is made according to the power required to generate at that time. Electronic valves also allow the flow of gas leaving the evaporator to be regulated, thus ensuring a reduction in the condensing pressure, especially in winter or at night, while maintaining a constant pressure in the evaporator.


Freon precision air conditioners use only environmentally friendly and ozone-free Freon R410A.


In heat exchangers consisting of aluminum plates and copper tubes, which are installed in freonine precision control devices when the air is vented at the bottom, the surface of the heat exchangers can be additionally covered with moisture-absorbing - hydrophilic materials to prevent condensate leakage. Coating the surface with these materials reduces heat exchange as well as inevitably increases the dimensions of the heat exchanger. However, surfaces are coated with hydrophilic materials whenever it is necessary to dehumidify the ambient air. For this reason, when designing freon precision air handling units, it is necessary to note when the premises where the exact microclimate parameters will be maintained are intended to work for many people or if large quantities of fresh air are to be supplied to those premises.


Adequate air filtration is one of the most important requirements in data centers, where the most important thing is not only to ensure uninterrupted operation of the device and also to protect data. It is no less important to ensure excellent supply air quality in administrative buildings as well.

To meet these needs, Tecnair LV precision-controlled air conditioners are equipped with self-cleaning G4 class filters as standard. In case of additional requirements, higher - E7 class filters can be ordered additionally.

In precision-controlled air conditioners, the filters are mounted diagonally so that they are crossed by the air before entering the heat exchanger. Their large surface area reduces the speed of the air passing through them, thus ensuring better air filtration and lower energy consumption.


Free-cooling function and mechanical cooling are available. If the outside air temperature is higher and sufficient return water parameters from the outdoor unit can no longer be ensured, one or two compressors are switched on for a certain time interval. The latter operate only to the extent necessary to ensure stable maintenance of the precision control parameters. This operating mode also saves energy, although not as efficiently as operating in the Free-cooling mode alone.





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