Annual Energy Performance of a Solar/Biomass HVAC System: Experimental Characterization through Concise Cycle Tests

This paper presents main results of Concise Cycle Tests (CCTs) carried out on the HVAC system developed under the Hybrid-BioVGE H2020 project. This system is driven by renewable energy sources (i.e., solar energy and biomass) and provides for space heating and cooling for small-scale residential and commercial buildings. The most innovative element of the HVAC system is a thermally-activated variable geometry elector (VGE) chiller, which provides for the building cooling load. Seasonal performance of the Hybrid-BioVGE system were assessed experimentally for both heating and cooling operating mode, according to the Whole System Testing (WST) methodology implemented by Institute SPF. Some components of the system were physically installed in the test bench, while other elements were simulated in TRNSYS and their performance was emulated and given to the test rig actuators according to the Hardware-in-the-Loop approach. Results point out that a significant part of the system energy demand can be satisfied by solar energy during the heating season: solar fraction is higher than 83% and, consequently, only 17% of the space heating energy need is provided by the back-up biomass boiler. On the contrary, the system energy performance for cooling operating mode is much lower than expected from numerical simulations. No sufficient cooling energy is supplied to the building due to the lack of cooling power from the VGE. Test results point out that a different control function to manage VGE operation must be defined necessarily.