Access to natural daylight and connection to the outdoor environment is one of the key elements of contemporary architecture. This design concept is characterized in buildings by large area glazing. However, large openings without proper shading strategy can cause visual and thermal discomfort for occupants in building perimeter zones. Electrochromic glazing can dynamically tint and vary its visual and thermal properties. EC glazing can prevent large amounts of solar energy from passing into the building interior to prevent over-heating.
This paper focuses on analyzing how Electrochromic (EC) glazing can affect occupant thermal comfort. Advanced human thermal comfort model developed by UC Berkeley and Center for Built Environment (CBE) was used in this study to predict body comfort and sensation. The level of accuracy of advanced thermal comfort model which can predict comfort for local body parts makes it a unique tool for assessment of comfort under non-uniform environments which is common due to variation in solar angle and solar radiation intensity.
For assessing thermal comfort performance of the Electrochromic glazing, two identical offices spaces, one with Electrochromic glazing in multi-zone configuration and one with low-E glazing were modeled. Thermal comfort and sensation of manikin were compared from both rooms at local and overall level. The analysis result showed that multi-zone Electrochromic glazing could significantly improve the thermal comfort levels of manikin model. Analysis result was reported in terms of color-coded manikin and interior solar radiation model for the selected hour that occupant receives direct sunlight penetration.
Electrochromic (EC) technology plays a major role in the development of dynamic smart glazing that can be controlled automatically and modulates transmitted heat and light. EC devices are multilayer systems
Thermal comfort is defined as “that condition of mind which expresses satisfaction with the thermal environment and is assessed by subjective evaluation (ANSI/ASHRAE Standard 55-2010) Thermal comfort is difficult to
UC Berkeley Thermal Comfort Model (BCM) has been used to predict thermal comfort for a wide range of solar angles. This multi-segment model predicts skin and core temperatures, sensation and
SageGlass EC glazing was modeled in three horizontal zones for maximizing the thermal comfort and heat control performance while still admitting sufficient daylight and controlling the sunlight glare. For the
Scenario 1: Conventional façade with overhang vs. SageGlass
Even in the middle of winter, there is sufficient solar radiation on the southeast elevation in a northern climate (Pennsylvania) to cause
Thermal comfort performance of the EC glazing was compared with low-E glazing in two case studies: conventional façade with overhang facing south-east and simple conventional façade facing west. EC glazing
Arens, Edward, Hui Zhang, and Charlie Huizenga. "Partial-and whole-body thermal sensation and comfort—Part I: Uniform environmental conditions." Journal of thermal Biology 31, no. 1 (2006): 53-59.
Arens, Edward, Hui Zhang, and Charlie Huizenga. "Partial-and whole-body thermal sensation and comfort—Part II: Non-uniform environmental conditions." Journal of Thermal Biology 31, no. 1 (2006): 60-66.
Clear, R. D., Vorapat Inkarojrit, and E. S. Lee. "Subject responses to electrochromic windows." Energy and Buildings 38, no. 7 (2006): 758-779.
Dussault, Jean-Michel, and Louis Gosselin. "Office buildings with electrochromic windows: A sensitivity analysis of design parameters on energy performance, and thermal and visual comfort." Energy and Buildings 153 (2017): 50-62.
Lee, Eleanor S., Stephen E. Selkowitz, Robert D. Clear, Dennis L. DiBartolomeo, Joseph H. Klems, Luis L. Fernandes, Greg J. Ward, Vorkapat Inkarojrit, and Mehry Yazdanian. "Advancement of electrochromic windows." Lawrence Berkeley National Laboratory (2006).
Page, Jessen, Jean-Louis Scartezzini, Jérôme Kaempf, and Nicolas Morel. "On-site performance of electrochromic glazings coupled to an anidolic daylighting system." Solar Energy 81, no. 9 (2007): 1166-1179.
Piccolo, A. "Thermal performance of an electrochromic smart window tested in an environmental test cell." Energy and Buildings 42, no. 9 (2010): 1409-1417.
Roudsari, Mostapha Sadeghipour, Michelle Pak, and Adrian Smith. "Ladybug: a parametric environmental plugin for grasshopper to help designers create an environmentally-conscious design." In Proceedings of the 13th international IBPSA conference held in Lyon, France Aug. 2013.
Ulrich RS. “Natural versus urban sciences: some psycho-physiological effects. Environment and Behaviour”, (1981), 13, 523-556
Wang, Z., H. Zhang, E. Arens, D. Lehrer, C. Huizenga, T. Yu, and S. Hoffman. "Modeling thermal comfort with radiant floors and ceilings." (2009).