A photovoltaic electrochromic window was developed by combining electrochromic glass with photovoltaic window. The photovoltaic electrochromic window is installed with a solar cell layer photovoltaic module on the surface, which is connected with the inner electrochromic glass layer chromic module. It can not only be self-sufficient to achieve the purpose of energy conservation, but also can use the energy generated by the photovoltaic module to freely control the working condition of the color-changing module to achieve the regulation of the indoor lighting environment. In order to study the system performance of the new designed photovoltaic electrochromic windows under different working conditions, a test platform for the comprehensive performance of power generation and lighting was established. According to the test results, it has been shown that PV electricity supplied for color window change can be satisfied with the discoloration modules needed. Under the fading condition, the transparent transmission rate is 13%, and the transmittance under shading condition is much smaller. It means that completely shading mode have a better control on the indoor lighting environment in sunny day compared with transparent fading. In order to deeply analyze the influence of photovoltaic electrochromic windows on indoor lighting environment, a comparative test was conducted between ordinary windows and photovoltaic electrochromic windows under various climatic conditions, and the test data was analyzed through the dynamic evaluation index of lighting environment, including the percentage of total natural lighting time DA and effective lighting illumination UDI. The comparison test results showed that photovoltaic electrochromic windows, compared with ordinary windows, can create a better lighting environment in sunny days under different working conditions. The coupling of photovoltaic modules and electrochromic modules enables photovoltaic electrochromic windows to regulate indoor light environment more flexibly.
Keywords Photochromic glass, Photovoltaic Windows, Lighting environment, Daylighting performance, BIPV