A comprehensive review on building integrated photovoltaic systems: Emphasis to technological advancements, outdoor testing, and predictive maintenance

Building integrated photovoltaics (BIPV) has enormous potential for on-site renewable energy generation in urban environments. However, BIPV systems are still in a relatively nascent stage with few commercial installations. Therefore, applied evaluation of small or medium-scale outdoor testbeds is critical to better understand the performance, reliability and operational issues associated with BIPV systems. This in turn helps early BIPV adopters in obtaining benchmark values and making more informed decisions during the system planning phase itself. On this viewpoint, this article provides a comprehensive overview on the global BIPV market, products, technologies, and applications. Also, given the importance of real-world testing and data analytics, this work conducts an in-depth analysis of 35 different BIPV outdoor test systems and its test results reported in literature. The assessment is carried out in two steps: (i) description of the testbed systems using various electrical, environmental, and physical factors that are monitored and reported; and (ii) evaluation of the testbed results with a focus on the quantitative electrical performance and economic parameters. A set of critical performance parameters has been defined, compiled, and quantitatively analyzed in this manuscript for the comparative study on various BIPV testbeds: 1) test duration, 2) specific energy yield, 3) energy efficiency, 4) system type, 5) module interconnection, 6) inverter efficiency, 7) performance ratio, 8) payback period and 9) unit energy cost. While no specific methods are available to quantify the performance of BIPV systems, an assessment based on annual specific yield is proposed in this review to identify underperforming test beds. With the proposed benchmark, the investigations reveal that almost 60% of the test beds reviewed are underperforming. Furthermore, based on the implications attained, some suggestions to improve the performance of existing test beds and the scope of utilizing such systems for predictive maintenance are provided. With the growing importance of outdoor test bedding, this document is envisaged to serve as a valuable reference for engineers, architects, buildings owners and scientists working on BIPV systems.