Measurement Evaluation and Simulation of an Innovative Drainback Solar Combi-System
Abstract
This paper presents an innovative drainback solar combi-system constructed in a new building during the year 2016. The system is unpressurized, and the same heat transfer fluid circulates from the solar collectors to the air-handling unit delivering the heat to the building. The number of heat exchangers is thereby minimized. The first measurement data show a lower system performance than expected, which can be explained on the one hand by differing heat demand compared to what was originally planned and on the other hand by improvement potentials, especially regarding the control strategies. TRNSYS simulations highlight that simple modifications of the control strategy could more than double the saved final energy. Detailed calculations nevertheless show that heat costs (LCoHov,fin) still remain between 24.5 and 30 % higher compared to a conventional heating system.