Mathematical modelling and performance analysis of a semi-transparent thin film PV glazing insulated with vacuum layer

This paper presents a novel design of a semi-transparent thin-film PV glazing insulated with vacuum layer. The vacuum glazing unit proposed in this study consists of two parallel glass panes; thin-film PV glass of an a-Si type separated from a 4 mm hard low-e coated glass pane by an approximately 0.3 mm vacuum gap called PV VG-2L. A mathematical model was developed and solved in MATLAB. The simulation allows both thermal and electrical performance analysis. The developed model was validated against the experimental results. To carry out the experiment, PV VG-2L was developed using low-temperature high-level vacuum method. The thermal performance was evaluated indoors using an innovative air to air source thermoelectric (TEC)-driven calibrated hot box built at the Department of Architecture and Built Environment, the University of Nottingham by closely following ISO 12567 Standards. At temperature difference of 20 ˚C, the average measured total U-value was found at 1.6 W/m2K with the average temperature difference between the internal and external surface was 13 ˚C. From the analysis, the computed percentage difference for the glazing internal and external surface temperatures and U-value are 1.3%. 8.6% and 3.0% respectively. The theoretical and experimental results are concluded to be in good agreement and hence the model is proven valid. Using the validated mathematical model, the performance of PV VG-2L was simulated under real conditions. The promising U-value implies its range of potential applications can be improved depending on the energy needs and applications, such as for BIPV solar façade (PV curtain walling) in commercial buildings, greenhouses, skylight and conservatory. The next step or part two of the research will be on the proof of concept prototype development of the innovative thin-film PV glazing with vacuum insulated layer glazing and the experimental validation of the mathematical model