Sun as Infrastructure - Models of Infrastructural Solar Heating and Cooling

The pilot plant ‘InfraSUN – Sun as infrastructure’ is being built at Jožef Stefan Institute campus in Ljubljana, based on the integration of solar heating and cooling into existing HVAC installations.

The setup serves as an object of demonstration and testing of emerging, immature solar thermal (ST) technologies including innovative vacuum tube heat pipe ST collectors and advanced small-scale absorption chillers. A heat recovery is installed in order to improve the overall energy efficiency of the system.WEB1INFRASUN

The main competitive advantages of the selected tube collector’s technology provided by Viessmann Solar are robustness, low operational and maintenance costs as well as wide temperature range of 60°C to 130°C. The solar thermal system is installed on the flat roof directly above the cooled premises with an area of 340 m2. A simulation of cooling needs has lead up to the solar field of 648 tubes, equivalent to an aperture area of 60 m² and the thermal power of about 41 kWth. In order to balance the thermal energy demand a heat storage tank is installed. WEB2

The cooling system is composed of 2 small-scale Sortech adsorption chiller units, which can be used to cool facilities as well as technical processes with chilled water in a temperature range between 6°C and 20°C. During the summer peaks, the set of cooling devices is estimated to be sufficient to lower the inside air temperature of the facility by approximately 7°C. Hybrid cooling tower is installed on the roof for heat rejection from the chiller re-cooling circuit. Compared to conventional cooling systems, up to 70% reduction of electricity consumption is expected.

The plant has been put into operation in the beginning of July 2014. Monitoring and measuring processes and the key characteristics of its operations that determine energy performance, environmental impact and economical aspects are being implemented. The evaluation of the results will be done continuously throughout the project lifetime for at least one year. Real-time visualization of the system status and characteristic values will be accessible on the web in August 2014.WEB3

Awareness of the installed technologies and solutions will be enhanced by promotional activities and visits to the pilot plant, which is open to the public on previous announcement to the pilot plant administrator. For more information, please, contact

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