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• Semi-transparent thermal assessment revealed that least transparency CdTe PV glazing can have U-values as low as 1.52 W/m2K. • The use of least transparency PV glazing can reduce 96% of solar heat gains and 23.2% of cooling energy compared to conventional clear glazing. • South-west building orientation achieved better energy saving over all sampled transparency. Semi-transparent PV glazing are promising in Building Integrated Photovoltaic (BIPV) applications. They provide daylight control, energy saving and power generation. The selection of optimal Photovoltaic (PV) glazing requires the accounting for various factors such as location, orientation and glazing transparency. In this work, thermal performance of Cadmium telluride (CdTe) based semi-transparent PV glazing of different transparencies was evaluated in UK for South and South-West orientations. Thermal performance was analysed in terms of U-value, SHGC and cooling load. Results revealed that least transparency CdTe PV glazing can have U-values as low as 1.52 W/m2K. The use of least transparency PV glazing can reduce 96% of solar heat gains and 23.2% of cooling energy compared to conventional clear glazing when used in South-West orientation. The selection of optimum glazing was discussed taking into consideration occupants' optical comfort and health. [ABSTRACT FROM AUTHOR]

In this work, carbon counter electrode perovskite was developed at the laboratory environment and building integrated photovoltaic (BIPV) window application using this material was investigated. At 1 sun (1000 W/m2) continuous incident solar radiation from an indoor simulator, this particular type of perovskite had 8.13% efficiency. Average solar and visible transmittance of this perovskite BIPV window was 30% and 20% respectively. Solar heat gain for different incident angle was evaluated for this perovskite glazing. For the University of Exeter, Penryn (50.16° N, 5.10° W) UK location, solar heat gain coefficient (SHGC) or solar factor (SF) varied from 0.14 to 0.33 at the highest and lowest incident angle respectively. Overall heat transfer coefficient (U -value) of 5.6 W/m2K was realized for this glazing while calculation was performed by window performance analysis programme, WINDOW 6.0. Daylight glare control potential of this glazing was investigated using subjective rating methods and comfortable daylight penetrated through glazing in a typical cloudy condition. Colour properties of this material showed that 20% visible transmittance is threshold limit, and below this value colour or visual comfort using this glazing is not achievable. • Spectral behaviour was studied immediately after fabrication of perovskite. • Variation of transmittance and solar factor with solar incidence angle was analysed. • Daylight glare analysis was carried out for different prevailing day in Penryn, UK. [ABSTRACT FROM AUTHOR]

• Test cell characterization was performed to evaluate thermal performance of CdTe BIPV glazing. • Visible transmission of this CdTe BIPV window is 25%. • Overall heat transfer coefficient of 2.7 W/m2 K was found for CdTe BIPV glazing. Semi-transparent photovoltaic (PV) technology is attractive for building-integrated photovoltaics (BIPV) due to its ability to lower the admitted solar heat gain, to control the penetrating daylight and to generate onsite benevolent direct current power. In this work, semi-transparent cadmium telluride (CdTe) based BIPV as window was experimentally characterized using outdoor test cell in temperate UK climate. Spectral measurement confirmed its 25% visible transmission and 12% solar transmission. Thermal transmission and solar heat gain coefficient were calculated from measured thermal data. Overall heat transfer coefficient (U -value) of 2.7 W/m2 K was found for outdoor and indoor characterization of CdTe BIPV window. A comparison with single glazed window has been produced emphasis its feasibility for Facade buildings. [ABSTRACT FROM AUTHOR]

• Thermal comfort using building integrated photovoltaic-vacuum system was calculated. • The indoor room temperature for BIPV-vacuum glazing was calculated from one-dimensional heat-model. • Vacuum-PV-single glazing structure was found to be suitable for UK climate. Building integrated photovoltaic (BIPV)-vacuum system is promising for advanced window application due to its ability to reduce heat transfer, control over admitted solar heat and generates environmentally benign electricity. In this work, numerically thermal comfort for an unfurnished room comprising of BIPV-vacuum glazing was evaluated for the United Kingdom (UK) climate. Required parameters to determine thermal comfort, one-dimensional heat transfer model was developed and validated for BIPV-vacuum glazing and results were compared with BIPV-double-pane glazing system. PV cell temperature difference between these two different types of glazing was 24 °C. For the UK climate, BIPV-vacuum glazing offered 26% higher room temperature at clear sunny day compared to BIPV-double system. BIPV–vacuum glazing system provided soothing or comfortable thermal comfort during mid-day period for a clear sunny day at temperate climate. In a combined BIPV-vacuum glazing, it was also predicted that vacuum glass facing external ambient is suitable for the UK climate whilst vacuum glass facing internal room ambient is applicable for Indian climate. [ABSTRACT FROM AUTHOR]

• Explanatory bibliometric and thematic analysis of building integrated photovoltaic (BIPV) system are presented. • The collaborative association between organizations and authors are presented. • By using keyword and keyword co-occurrence analysis, trending topics and the evolution of research are explored. • Discussion of the primary issues and recommendations of BIPV systems for reducing energy need in buildings. The present article aims to identify emerging trends in the building integrated photovoltaic (BIPV) field through an analysis of the most prominent articles, authors, keywords, sources, and countries through bibliometric analysis of the same. To fulfil the study's aims, 1552 articles published in Scopus databases between 1985 and 2022 are reviewed and analysed using the Bibliometrix - R software, VOSviewer, and SciMAT. Since 2016, the results indicated that the number of publications per year in this domain has consistently increased. The China, UK, and USA were the most prominent contributors to this research area in terms of overall publications and citations. In addition, the results highlight the most significant sections of the article from the perspective of the highest citations, publications, keywords, and authors. Through co-citation analysis and keyword co-occurrence network, the major knowledge base and the most prominent hot themes of BIPV study field were identified. The minimum number of co-occurrences of keywords is set to the value of five which results in 166 threshold keywords out of these 146 keywords are selected and divided into 9 clusters. Cluster-1 (Red) contains a total of 32 keywords. BIPV has the highest connection of 63 links and 67 documents followed by phase change material (52 links and 45 documents). The results pointed to a potential gap in the literature regarding the use of artificial neural networks in BIPV systems. [ABSTRACT FROM AUTHOR]

Various studies have assessed the energy performance alterations affected by the novel technology of Building-Integrated Photovoltaic in Double-Skin Facades (BIPV-DSF), while lighting performance tied to the BIPV-DSF has not received much attention. This paper provides numerical modelling to assess the effect of BIPV-DSF on both indoor visual condition and energy consumption for an office module under a typical climate in the United Kingdom. The proposed study was focused on the comparisons between a reference case (a DSF office module with both layers using clear double glazing) and a design case of the same office module with BIPV-DSF using semi-transparent Amorphous Silicon PV glazing. Results show a significant drop in maximum daylight illuminance of 73% by configuring the BIPV-DSF with reference to the regular DSF. It was also reported the resultant average and minimum daylight factors (0.65% and 0.00%) were not able to meet indoor visual comfort requirements for office environments. Furthermore, it was found that the use of BIPV-DSF resulted in a net increase of 8% in building energy consumption over the reference DSF. Therefore, it is concluded that in the present context the BIPV-DSF is not viable for a commercial installation under the UK's climate conditions. [ABSTRACT FROM AUTHOR]

• A switchable photovoltaic window based on thermotropic hydrogel is developed. • Selected hydrogel can reversibly switch between highly transmissive and scattering states. • The window performance is evaluated by indoor and outdoor experiments. • This window can passively control daylighting and heat gain during hot sunny days. • This window offers better electrical performance than conventional PV glazing. Daylighting control technologies have become an essential part of sustainable building design to reduce overheating, glare and energy consumption in buildings. In this paper, a smart glazing system where a Building Integrated Photovoltaic (BIPV) glazing is coupled with an optically switchable thermotropic hydrogel layer is proposed to improve the daylighting control and electricity generation performance of traditional BIPV glazings. Thermotropic (TT) hydrogels made of various weight percentage combinations of hydroxypropyl cellulose (HPC) polymer, gellan gum and sodium chloride (NaCl) salt were synthesised and first evaluated by visible-near-infrared spectroscopy. Subsequently, small-scale prototypes of the proposed BIPV thermotropic (BIPV-TT) laminated glazing based on these TT hydrogels were fabricated and characterised experimentally under controlled laboratory conditions. The TT hydrogel, which was synthesised of 6 wt% HPC, 0.5 wt% gellan gum and 4.5 wt% NaCl, was selected for further experimental characterisations in a dynamic outdoor environment, due to its appropriate transition temperature of 30.7 °C for use in mild climates with a wide modulation range of solar transmittance from 85.8% (in the transparent state) to 9.6% (in the light-scattering state). The outdoor tests were conducted in Nottingham, the UK, on typical summer days with sunny and partial cloudy conditions. The results showed that using the prototype BIPV-TT laminated glazing can reduce up to 80% of the solar radiation transmitted into the outdoor test cell, while providing up to 12% higher electrical power outputs, compared to its counterpart system with no thermotropic hydrogel applied. [ABSTRACT FROM AUTHOR]

• A comprehensive life cycle assessment approach for renewable multi-energy systems. • Life cycle primary energy consumption, economy cost, and carbon emission is evaluated. • Sensitivity analysis on rated capacity, life span, recycle ratio and interest rate. • Representative office building design in UK and real-life inventory data is adopted. • Useful guidelines for government in policymaking and engineers in retrofitting works. In response to the gradual degradation of natural sources, there is a growing interest in adopting renewable resources for various building energy supply. In this study, a comprehensive life cycle assessment approach is proposed for a renewable multi-energy system (MES) to evaluate its primary energy consumption, economy cost and carbon emission from cradle to grave. The MES, consisting of passive side and active side, is fully driven by renewable energy including solar, wind and biomass. On the passive side, building integrated photovoltaic, solar collector and wind turbines are adopted. On the active side, the biomass-fuelled combined cooling heating and power system (CCHP) serves as the primary energy supplier. The electric compression chiller and biomass boiler are adopted when the thermal energy from the CCHP system is not sufficient, while electricity is imported from the city power grid when the electricity demand is low. A representative office building in the United Kingdom and real-life inventory data is adopted to demonstrate the effectiveness of the proposed life cycle assessment approach. Through life cycle assessment, the advantages and disadvantages of the MES are compared with the reference CCHP system and conventional separate system in view of life cycle primary energy consumption, economy cost and carbon emission. Moreover, to gain an insight into the life cycle performance, the sensitivity analysis is conducted on the rated capacity of the power generation unit, climate zones, life span, recycle ratio and interest rate. The life cycle cost of MES is relatively higher than the conventional separate system mainly owing to the high construction cost of BIPV, wind turbine, solar collector and biomass feedstock. However, its life cycle primary energy consumption and carbon emission are much lower. It is believed that the proposed life cycle assessment approach can provide useful guidelines for government in policymaking and for building engineers in retrofitting works. [ABSTRACT FROM AUTHOR]