© 2019 the Authors 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.

© 2019 International Solar Energy Society 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.

© 2018 the Authors Low heat loss vacuum glazing offers high heat insulation for indoor space, which reduces the building's heating energy demand. However, the transparent nature of this glazing allows similar daylight to double glazing that creates discomfort glare. Double pane semi-transparent type photovoltaic (PV) glazing introduces control of solar heat gain, daylight and generates clean electricity. The transparent portion between regularly distributed PV cells allows light penetration. Addition of these two technologies can offer low heat loss PV-vacuum glazing that will control heat loss, heat gain, and daylight and generate renewable power. In this work, two different areas of multicrystalline PV cells were employed to form 35% and 42% transparent PV-vacuum glazing. Spectral characterisation, glazing factor and entering light quality through the transparent part of this PV-vacuum glazing were evaluated. Colour rendering and correlated colour temperature of this glazing were compared with an electrically actuated switchable suspended particle device glazing.

© 2018 Solar and luminous light transmission control using Cadmium Telluride (CdTe) based PV glazing systems (15 cm × 15 cm × 0.6 cm) were evaluated in this work. Indoor spectral characterisation showed that average solar transmission for investigated three different CdTe glazing systems were 5.77% (CdTe1), 9.54% (CdTe2) and 12.34% (CdTe3). Spectral behaviour of reflections in the range of solar and visible wavelengths was similar for these three different transparent CdTe glazing. Near infrared (NIR) reflection was higher compared to luminous reflection after 1500 nm for all three glazing systems. Solar factor (SF) for CdTe1, CdTe2 and CdTe3 glazing were 0.23, 0.28, 0.26. CdTe3 is the best candidate for glazing application as it has 113% higher luminous transmission while SF only increases by 21% compared to CdTe1.

© 2019 by the authors. In this work, a hybrid microgrid framework was created with the assistance of a photovoltaic (PV) and wind turbine (WT) generator. Additionally, bidirectional control mechanisms were implemented where an AC system was integrated with permanent magnet synchronous generator (PMSG)-based WT and a DC system was integrated with a sliding mode algorithm controlled maximum power point tracker (MPPT)-integrated PV system. The wind and PV interconnected microgrid system was mathematically modeled for steady-state conditions. This hybrid microgrid model was simulated using the MATLAB/SIMULINK platform. Optimal load management strategy was performed on a chosen hybrid microgrid system. Various case studies pertaining to connection and disconnection of sources and loads were performed on the test system. The outcomes establish that the system can be kept up in a steady-state condition under the recommended control plans when the network is changed, starting with one working condition then onto the next.

© 2019 the Authors 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.

© 2018 Elsevier Ltd Suspended particle device (SPD) glazing is an electrically actuated switchable glazing. It requires alternate current (AC) power supply to switch from opaque to transparent state. To power this glazing using PV device requires inverter. Optimization of AC powered switchable SPD glazing using photovoltaic (PV) device has been evaluated using loss of power supply probability (LPSP). Electrically switchable direct current (DC) powered electrochromic glazing was also considered in this investigation as it doesn't need any inverter to couple with PV. It is concluded that behaviour of these glazings is the dominant factor in performance optimization outweighting than azimuthal orientation and inclination of PV.

© 2018 Elsevier Ltd Building energy reduction requires highly advanced low heat loss, heat gain and comfortable daylight allowing glazing. Presently available glazing systems are classified mainly in two categories, controlling solar heat gain and controlling low heat loss. Low heat loss through glazing systems can be achieved by (i) suppression of convection in the air between the outer panes by use of multiple glass panes or aerogels, (ii) having an inert gas or vacuum between the panes to reduce or eliminate respectively convective heat transfer. In all these systems, low emissivity coatings are also required to reduce the radiative heat transfer. Low heat glazing allows large areas of a building façade to be glazed without large attendant heat losses. However, they require the addition of an ability to switch from transparent to opaque to avoid excessive solar heat gain and to control glare. Electrically actuated electrochromic, liquid crystal and suspended particle device glazing systems and non-electrically-actuated thermochromic, thermotropic, and gasochromic glazing systems offer control of solar heat gain control and daylight. Recent relevant developments are reviewed with the contemporary status of each technology provided.

© 2017 Elsevier B.V. The daylighting performance of a polymer dispersed liquid crystal (PDLC) switchable glazing has been evaluated using an unfurnished outdoor south-facing test cell with a glazing-to-wall ratio of 1:9. Useful daylight illuminance levels (UDI) were determined for clear sunny, intermittent cloudy and overcast cloudy days. Daylight glare indexes (DGIN) was calculated for the PDLC glazing in its transparent and translucent states. An electrically-actuated adaptive PDLC switchable glazing with transparency that varied between 27% and 71% was able to control daylight glare.

© 2017 Elsevier Ltd in this study, intermediate transmissions, colour-rendering index (CRI) and correlated colour temperature (CCT) of an electrically actuated, switchable polymer dispersed liquid crystal (PDLC) glazing have been investigated. This 0.03 m2 PDLC glazing changes its state from translucent to transparent in the presence of a 20 V AC power supply. Modulation of visible and NIR transmissions were observed for different applied voltages and no modulation was found in the UV range. For this particular type PDLC glazing, the CCT and CRI varied between 5430 K and 6100 K and 93 to 98, while luminous transmittance varied from 0.27 to 0.71 respectively. Low contrast ratio between the translucent and transparent states of this PDLC glazing offered a strong linear correlation between CCT and CRI.

© 2017 Elsevier B.V. Polymer dispersed liquid crystal (PDLC) glazing is a potential electrically actuated switchable adaptive glazing for low energy building application as it become transparent in the presence of alternating current (AC) power supply and become translucent/opaque without power supply. Optical properties and protection factor for a particular type of PDLC glazing was investigated in this work. Using UV–vis–NIR (1050) spectrophotometer spectral transmittance of this glazing was measured for its both states. PDLC on state needs 20 V AC power supply to offer 41% transmission while without any supply this glazing becomes 23% transparent. In the switch off state LC particles offer forward scattering which makes this glazing translucent with high 82.6% haze. Solar factor for PDLC transparent and translucent state was found to be 0.53 and 0.39 respectively. Glazing protection factors were calculated using spectral transmittance data. Switchable transparency and switchable solar factor makes this glazing suitable to match adaptability of building occupants.

© 2018 Elsevier B.V. Electrically activated switchable polymer dispersed liquid crystal (PDLC) is suitable for adaptive windows. A particular type requires 20 V to become 71% transparent while in the absence of power it is 27% transparent. Glazing transmission changes with light incident angle. As the clearness of a sky changes the fraction changes alter of direct insolation (that has an azimuthally changing incident) and diffuse insolation (that has a largely constant incident). Thus, the effective overall incident angle determining the glazing transmittance also changes. In this work for the first time, the variation of PDLC glazing transmission with clearness index has been investigated. For diffuse sky condition, single glazing transmittance value can be used below a particular clearness index for building energy calculation. This threshold clearness index changes with different azimuthal direction. In Dublin for south facing vertical plane PDLC glazing, yearly usable single transmittance (38% for transparent and 25% for translucent state), transmitted solar energy (TSE) (70 W/m2 for transparent state and 20 W/m2 for translucent state) and solar heat gain coefficient (SHGC) (0.17 for transparent state and 0.005 for translucent state) for transparent and translucent states were investigated.

© 2018 the Authors the colour rendering index (CRI) and correlated colour temperature (CCT) of transmitted daylight through a DSSC glazing is an essential parameter for building interior space comfort. Six small-scale dye-sensitized solar cells (DSSCs) were fabricated by varying TiO2 electrode thickness, which offered luminous transmittance between 0.19 and 0.53. Below 0.5 transmittance, the CRI for this TiO2 electrode based DSSC glazing was less than 80. A strong linear correlation was found between CCT and CRI. The CRI of 53% transparent DSSC glazing had only 2.7% lower CRI than 77% transparent double glazing and 72% transparent vacuum glazing.