Dynamic parametric models for the holistic evaluation of semi-transparent photovoltaic/thermal façade with latent storage inserts

• Published in: Applied energy 2020-12, Vol.280, p.115994, Article 115994
• Main Authors: Arkar, C., Žižak, T., Domjan, S., Medved, S.
• Format: Article
• Language: English
• Subjects: Building-integrated photovoltaics façade structures; Dynamic thermal insulation; In-situ experiments; Multi-parametric regression models; PCM solar storage
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2020.115994

[Display omitted] •Diurnal and dynamic energy efficiency metrics of photovoltaic façade were developed.•Design of photovoltaic facade and PCM inserts were optimized and validated.•Regression models of metrics were made based on heating season in-situ experiments.•Energy balance in heating season for different climate conditions is presented. High energy efficiency, energy autonomy, and improved living conditions are basic requirements of sustainable buildings. Advanced building envelope structures can provide these requirements. In the present paper, multipurpose façade structure designed as semi-transparent modular building-integrated photovoltaic façade with a forced ventilated cavity and enhanced heat storage capacity, using encapsulated phase change inserts installed on inner glass pane of photovoltaic module and on building envelope, is evaluated. The design of the façade structure, including simultaneous optimization of photovoltaic cell-packing factor, phase change material inserts properties, and heat transfer by convection in air gap, was based on transient modeling. A 60% photovoltaic cell-packing factor enables the highest overall energy efficiency, while phase change material inserts on the inner glass pane of photovoltaic module have no impact on diurnal photovoltaic cell efficiency. However, a phase change material layer installed on the envelope decreases the diurnal heat losses by half at solar radiation of 2200 Wh/m2 day. The energy performance of an optimized modular structure was determined via in-situ experiments; the data were used for developing dynamic approximation models of energy efficiency indicators. It was found that multiple regression models with interactions and past values can predict dynamic responses with sufficient accuracy. Depending on the heating season’s climate conditions, the developed semi-transparent modular building-integrated photovoltaic façade decreases the energy needs 40% to 55% in comparison to the reference façade with solar energy utilization efficiency in the range between 44% and 63%. This proves that such structures can contribute to fulfilling of requirements of sustainable buildings.