SolarCooling Monitor - Evaluation of energy efficiency and operation modes of solar cooling systems for air-conditioning in buildings in Austria

Evaluation of ten newly installed solarthermal cooling systems in Austria as well as a large-scale plant in Lisbon to identify the plant’s performance using a monitoring analysis and comparing simulation.

Short Description




Initial situation/Motivation

To achieve the leap from passive houses with high energy efficiency to so-called ‘Energy-Plus-Buildings’, the integration of renewable technologies for heating and cooling is necessary, in addition to a reduction of the heating and cooling needs of the building. Solar thermal cooling offers a large potential of CO2 savings during the operation of the air conditioning in buildings, avoiding of the current summer peaks and saving of primary energy. At present, three technologies are available at the market:

  • Adsorption cooling systems
  • DEC-systems (Desiccant Evaporative Cooling)

Most of the existing solar cooling plants in Austria are initiatives of solar planners, solar collector manufactures or municipalities. The experience for system design and control of such systems is insufficient also due to a lack of available appropriate software tools.

Content and Aims of the project

This project should give an overview of the present quality of workmanship, energy performance and operation of solar cooling plants in Austria. Therefore, ten of the recently installed solar thermal cooling plants in Austria were selected, as well as a large-scale installation in Lisbon (Austrian plant Engineering and Construction Company) in order to examine the performance by means of simulation and monitoring. Herewith, important results of the present status of solar cooling systems in buildings should be pointed out and optimization potentials for a next generation of solar cooling systems should be identified.


  • Monitoring Evaluation of the solar cooling plants using a common evaluation procedure (Level 3 of IEA SHC Task 38 monitoring procedure)
  • Setting up dynamic simulation models for the installed solar cooling plants
  • Alignment of simulation results of solar cooling with actually measured plant behavior
  • Optimization of solar cooling plants using the monitoring and simulation results
  • Dissemination of experiences on national and international level

Results and conclusions

The results of transient simulations showed a higher primary energy saving potential for each solar cooling plant than actually achieved. The low electrical Coefficients of Performance (COPs) according to monitoring are resulting from the use of inefficient components (pumps, heat rejection), complex system configurations, poor system design or inefficient control strategies.

Monitoring and simulations also showed a high potential for Desiccant Evaporative Cooling (DEC) systems in Austria. The humidity recovery potential in winter leads to very high primary energy savings compared to a reference system with conventional technologies.


When planning, installation and facility management are carefully carried out high primary energy savings up to 80% compared to conventional cooling technologies can be achieved. The electrical COPs should range between 6 and 8, depending on the system configurations. The quality assurance is therefore a major issue as a next step for realisation of energy efficient solar cooling plants in Austria and abroad. The achieved know-how within this project has to be disseminated in the building sector. Furthermore, easily manageable design tools are needed.

Project Partners

Project management

Ing. Anita Preisler
AIT - Austrian Institute of Technology, Energy Department, Vienna

Project or cooperation partner

  • DI Alexander Thür PhD
  • DI Daniel Neyer
    Universität Innsbruck (UIBK-EEB)
  • DI Hilbert Focke
    ASIC – Austria Solar Innovation Center
  • SOLID, Graz

Contact Address

AIT - Austrian Institute of Technology, Energy Department
Ansprechperson: Ing. Anita Preisler
Giefinggasse 2, A-1210 Wien
Tel.: +43 50550-6634
Fax: +43 50550-6613