Analysis and optimization of the optimal transmittance range and WWR combination of electrochromic glass

Electrochromic glass has the capacity to modify the amount of heat gained in a room by altering the transmittance. However, commercially available low-transmittance electrochromic glass is not suitable for winter scenarios in high latitudes and cold regions, and it may increase a building's year-round energy consumption. Therefore, this paper conducted a year-long simulation experiment utilizing Grasshopper and Ladybug Tools software to evaluate the alterations in EUI, DA, and UDI of electrochromic glass across diverse light transmittance ranges. In addition, another factor affecting the energy consumption of a building, WWR, is investigated. The experimental results indicate that in a cold region such as Qingdao City, the optimal transmittance range for reducing building energy consumption is 40 %–90 %, while at 70 % WWR can minimize the annual energy consumption, which allows the EUI to drop by 14.3 %, or 36.39 kWh/m 2 , compared with the traditional glass at 30 % WWR. Electrochromic glass in the range of 0.1 %–90 % transmittance is more suitable when WWR exceeds 70 %. When targeting indoor light sufficiency, electrochromic glass in the 40 %–90 % transmittance discoloration range is the best choice, with 50 % WWR being the most optimized choice. In scenarios where the primary objective is to ensure indoor visual comfort, electrochromic glass in the 0.1 %–40 % transmittance range emerges as the optimal solution. This paper provides a comprehensive overview of the design, production, and application of electrochromic glass, in addition to offering fundamental data for the optimization of various control strategies.