iNSPiRe – Sorption Collector - Systemic Approach for Retrofitting Existing Buildings, Including Envelope Upgrading, High Performance Lighting Systems, Energy-Efficient HVAC Systems and Renewable Energy Generation Systems

Duration: October 2012 - September 2016
Contracting Authority/ Sponsors: EU Collaborative Project FP7, THEME [EeB.NMP.2012-2]; Grant agreement no: 314461
Project Partners: ClimateWell, Sweden; EURAC, Italy
Project Focus:
Air-based sorption collector
© Fraunhofer ISE
Air-based sorption collector (ClimateWell) at the outdoor test stand of Fraunhofer ISE.

Thermally operated solar cooling faces difficulties establishing itself as economically feasible technology in the small power range, in particular, due to high investment costs and system complexity. A sorption cooling system directly integrated into thermal flat plate collectors was suggested in previous projects as possible solution. Further development of this technology was included in one work package of the “iNSPiRe” project.

Previous projects showed that the direct integration of a sorption system into a thermal collector is technically feasible and that collector losses have the highest influence on overall efficiency. For this reason, the collector-integrated system was further developed within the scope of the “iNSPiRe” project. The focus was on the reduction of collector losses and simplification of the system concept. In particular, air should be used as heat transfer medium with the objective to directly integrate the collector into a facade and thus, to directly supply the building with heated or cooled air and to couple cooling of the sorption cooling system directly to the ambient air in the cooling case.

Partner ClimateWell integrated sorption tubes based on the LiCl/H2O working pair into a vacuum Sydney type vacuum tube collector. Fraunhofer ISE designed the corresponding heat exchangers (sorption side, evaporator/condenser side). For this purpose, simulation work (e.g., in COMSOL Multiphysics) and lab investigations on small prototypes were combined.

A prototype for the integration into a real metal glass facade element was characterized using the solar simulator as well as outdoor measurements and simulation models were calibrated using these measurements.

System simulations performed by project partner EURAC confirm the potential of the technology to provide heating and cooling energy-efficiently. However, they also show that economic feasibility is not given yet in the application in office facades compared to central compression systems despite efficiency increase and cost reduction.