Energy and emissions analysis of next generation electrochromic devices

The impact of buildings on the environment, energy consumption and climate change is significant, asthey use a large amount of resources across their life-cycle. Since windows play an important role in theoverall energy and environmental performance of buildings, emerging technologies are focused on theoptimization of these building components. Among window design technologies, electrochromic (EC)devices have received growing interest for their ability to dynamically manage the daylight and solarenergy entering buildings. Near-infrared switching electrochromic (NEC) glazed windows use a novel ECwindow technology that is able to continuously provide high transparency while modulating solar heatgains. This study evaluated the manufacturing phase of NEC windows to understand if their use phaseperformance comes at acceptable manufacturing burdens. This study also identified which constraintsare connected to the market shift to the novel technology, which can provide the research communitywith useful information to better design the technology as it develops. A comparative “cradle-to-gate”energy and emissions analysis was carried out between NEC and conventional EC windows.The obtained results for the Global Warming Potential of the conventional EC device was 85 kg CO2-eq/m2 and the Cumulative Energy Demand was 1680 MJ-eq/m2. Results for the NEC device were found tobe 50 kg CO2-eq/m2 and 1050 MJ-eq/m2, with the reduction primarily due to replacing the energyintensive thin film deposition used in conventional EC with a solution-based coating process. Finally,when an entire window is modeled (EC device, frame, glazing and sealing), the difference over conventionalEC, in terms of primary energy consumption, ranged for the whole window manufacturingfrom 15% to 21%, depending on the material of the frame.