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Conventional air conditioning in buildings consumes substantial energy contributing to an increase in greenhouse gas emissions, which aggravates global warming. Kirigami envelopes with reflective surfaces offer a promising option to reduce indoor heat gain. So far none has performed outdoor testing of kirigami envelopes nor numerical simulation to understand how they interact with the environment. To understand the impact of the geometric design of the kirigami shading system on both daylighting and temperature variation in the indoor environment, a series of prototypes and simulations is devised to investigate the real‐time shading behavior in an outdoor environment. Large‐scaled and silver‐coated kirigami‐based envelopes of different cut patterns and stretching ratios are fabricated and placed in front of custom‐designed chambers equipped with six thermo‐sensors. Simulation is performed to investigate the effect of light modulation and hence temperature inside the chamber, which corroborates with the experiments. The indoor daylighting pattern and temperature are significantly influenced by the geometry of the stretched kirigami envelope, and overall, both the indoor temperature and the spatial distribution of illuminance are more uniform compared with that without the kirigami envelope. These results indicate that the installation of kirigami envelopes can improve building energy saving and occupants' comfort. [ABSTRACT FROM AUTHOR]

Much of human exposure to ozone takes place indoors. However, few studies have focused on human ozone exposures in normally occupied residential houses in the U.S. urban environments. Only rare studies have explored the implication of building envelope design variables on outdoor ozone penetration. Our study reveals the extent to which outdoor ozone penetrates and persists in the occupied houses in one of the most ozone-polluted cities, as influenced by building characteristics, building geometry, envelope design variables, window conditions and urban meteorology conditions. Through a set of analysis and variable regressions, we found that (1) the ratios of indoor to outdoor ozone concentration (I/O) were higher with windows open (0.700 ± 0.13) than with the windows closed (0.53 ± 0.22); (2) the indoor ozone concentration is typically elevated when the outdoor ozone concentration is high; and (3) design variables such as exterior envelope finishes, wall surface area and window-to-wall ratio are reasonably effective predictors. Our results of health risk evaluation suggest that the observed levels of indoor ozone exposure could pose a considerable risk to human health. Further work is needed to discover how building envelopes can be designed, constructed and maintained to support occupant health. [ABSTRACT FROM AUTHOR]