Novel, Practical and Reliable Analytical Models to Estimate Electrical Efficiency of Building-Integrated Photovoltaic/Thermal (BIPVT) Collectors and Systems

Building-integrated photovoltaic/thermal (BIPVT) collectors are multifunctional products that replace conventional building materials in parts of the building envelopes, such as the facades and roofs. BIPVT collectors serve as novel building envelope material that can generate thermal and electrical energy simultaneously to be utilised in buildings. Despite the remarkable potential of BIPVT collectors and systems in mitigating energy consumed in building sector, until recently, they have received only limited attention since there has been no comprehensive attempt to date to optimise BIPVT collectors in terms of design, operation and climate oriented performance parameters. Electrical efficiency is a key performance parameter for BIPVT collectors. In this respect, easy, fast and reliable determination of electrical efficiency of BIPVT collectors is of vital importance for preliminary performance assessment of this technology under various design, operational and environmental conditions. Therefore in this research, novel, practical and reliable analytical expressions are developed to estimate electrical efficiency of air type BIPVT collectors as a function of design and climatic parameters. The most common configuration of BIPVT collectors (glass to glass BIPVT collector) is considered within the scope of this study, and analytical expressions are developed for this design. The accuracy of the analytical expressions is verified through previous experimental works in literature conducted under different climatic conditions. The results indicate that the electrical efficiency of glass to glass BIPVT collector is in good accordance with previous literature