ISI Pergine, Business Centre, Trento, Italy

Description of the application

The business center in Trento is a newly constructed two-storey high building with an area of about 10,000 square meters.
The plant system has been selected with the intent of providing medium-high quality standards for the tertiary sector, including summer cooling and forced ventilation. For the ventilation, implying large quantities of air treatment, an efficient energy recovery system has been provided. The owner of the building is TECNOFIN TRENTINA S.P.A. The province of Trento co-financed 32 % of the overall costs of the plant.

General description of the system

The system is based on an absorption chiller of 108 kW coupled with 240 m² flat plate collectors. The system is connected via a heat exchanger to the district heating. The distribution system is chilled beams for cooling and heating with low temperature (50–40 °C winter; 14.5–17.5 °C summer). The heat rejection system is done by a 175 kW wet cooling tower. Secondary hot water storage allows to face variations in solar radiation intensity (autonomy of 20'), ensuring system stability.
The comfort objectives (winter and summer air-conditioning, air changes, silent operation, reduction of air currents, individual climate control) have oriented the choice towards a mixed system with primary air and terminals with a relevant radiant component, both for heating as for cooling: for this purpose ceiling linear ventilated terminals were selected (the so called “chilled beam”).

Central air-conditioning unit


closed cycle

Nominal capacity

70 kWcold

Type of closed system


Brand of chiller unit


Chilled water application

chilled tubes



Heat rejection system

wet open

Solar thermal

Collector type


Brand of collector


Collector area

240 m2 aperture

Tilt angle, orientation

30°, 0° (south)

Collector fluid


Typical operation temperature

85 °C driving temperature for chiller operation


Heat storage

2 m3 water, other fluids,...

Cold storage


Auxiliary heating support

district heat

Use of auxiliary heating system

heating & cooling

Auxiliary chiller


- type

el. compression chiller

- capacity

120 kWcold

System performance

(Estimation performance data because the plant has to be yet operational)
Overall nominal thermal loads: The nominal winter thermal loads will be of the order of 229 kW and for this capacity has been sized the district heating system.
Whereas the winter situation the sum of the thermal loads of each single space corresponds to the overall building load, during the summer period, as well known, the global loads result inferior to the algebraic sum (each space is valued during its most critical hour according to its solar exposure, the overall building will have a unique critical hour which will not necessarily correspond to the maximum thermal load of all spaces).
Thus the sum of the summer loads (excluding thermal heat recovery) is of 188 kW, having a maximum contemporary load of 170 kW.
Under these conditions the solar collectors supply 145 kW. With this  thermal power the absorber can produce 108 kW.
When under cloudy sky conditions the thermal load (in absence of solar radiation) drops from 170 kW to 120 kW.
The compression refrigeration machine is thus selected to cover this capacity.

System reliability and overall success of the installation

Estimation: Generation of the 70 % of the site cooling utilising solar energy with CO2 emissions saving.

General information

Type of building  office building
Location  Trento, Italy
In operation since  -
System operated by  -
Air-conditioned area  - m2
Capacity  108 kW


Caption 1
Collectore area
Collectore area
Collectore area
System scheme
Collectore area

Clicking an image opens the gallery view.

Specific information

Further specific information about the system are included in the filled in technical questionnaire.



For more information on the project please feel free to contact:

Marcello Aprile