Numerical analysis of different designs of roll-bond absorber on PV/T module and performance assessment

This paper focuses on the optimal design of PV/T modules implementing roll-bond absorber. A dedicated tool including detailed pressure loss calculation and flow distribution in the absorber was developed to compare different design layouts (harp, serpentine and spiral) and channel sizes. The tool was calibrated against experimental data which confirmed its reliability to predict both electric and thermal performance. The model results outlined the importance of the circulating pump power consumption in the identification of the optimal configuration. The harp design achieves the best performance with 57.1% and 17.0% first law and net exergy instantaneous efficiency respectively assuming a 25 °C fluid inlet temperatures and NOCT conditions. The serpentine configuration achieves the highest thermal efficiency of 46% but suffers higher pressure drop which penalize the net power output of the system. Two innovative harp designs are proposed to reduce the hot spot connected to the junction box and uneven fluid distribution. Finally, the inlet fluid temperature has a strong influence on the flow rate inside the absorber affecting the optimal design option.