Photo-thermal decoupling CdTe PV windows with selectively near-infrared absorbing ATO nanofluids

Solar energy conversion and utilization are crucial for buildings. Photovoltaic windows are a promising path to improving building energy efficiency. This study proposes a novel photo-thermal decoupling cadmium telluride (CdTe) PV windows with selectively near-infrared absorbing antimony-doped tin oxide (ATO) nanofluids. The PV-ATO window features four concentrations (200/400/800/1000 ppm). Hot box experiment results show that PV-ATO windows can reduce the peak indoor air temperature by up to 2.56, 2.06, 2.86, and 2.72 °C respectively, while the corresponding peak illuminance is cut by 13.01 %, 12.37 %, 17.40 %, and 56.28 %. Measured transmitted spectra's correlated color temperature (CCT) of the PV-Water and PV-ATO windows are in the range of 4811.0～5271.0 K; color render index (Ra) is between 95.7～98.8; color fidelity index (Rf) is between 96.9～99.1; color gamut index (Rg) is between 97.6～99.3. Regarding color rendering performance, the PV-ATO windows can outperform conventional windows. Energy simulation results show that the comprehensive energy-saving ratios of different PV-ATO windows in Guangzhou, Changsha, Chongqing, and Wuhan can achieve −11.27 %, −20.38 %, −0.08 %, and −5.17 %. The study points to low concentrations of ATO nanofluids (200 ppm) as the recommended value. •CdTe PV glazing and ATO nanofluids combine as a novel photo-thermal decoupling energy-saving window.•Outdoor experiments prove PV-ATO windows can reduce air temperature by 2.86 °C with only 17.40 % decreased illuminance.•Measured transmitted spectra's color quality of PV-ATO windows can outperform conventional windows.•The most recommended PV-ATO 200 ppm windows can achieve simulated comprehensive energy savings of −20.38 %.