A New Dynamic and Vertical Photovoltaic Integrated Building Envelope for High-Rise Glaze-Facade Buildings

Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,and solar energy harvesting for glazed facades.In this study,we addressed these conflicts by introducing a new dynamic and vertical photovoltaic integrated building envelope(dvPVBE)that offers extraordinary flexibility with weather-responsive slat angles and blind positions,superior architectural aesthetics,and notable energy-saving potential.Three hierarchical control strategies were proposed for different scenarios of the dvPVBE:power generation priority(PGP),natural daylight priority(NDP),and energy-saving priority(ESP).Moreover,the PGP and ESP strategies were further analyzed in the simulation of a dvPVBE.An office room integrated with a dvPVBE was modeled using EnergyPlus.The influence of the dvPVBE in improving the building energy efficiency and corresponding optimal slat angles was investigated under the PGP and ESP control strategies.The results indicate that the application of dvPVBEs in Beijing can provide up to 131%of the annual energy demand of office rooms and significantly increase the annual net energy output by at least 226%compared with static photovoltaic(PV)blinds.The concept of this novel dvPVBE offers a viable approach by which the thermal load,daylight penetration,and energy generation can be effectively regulated.

A super sandstorm altered the abundance and composition of airborne bacteria in Beijing

Sandstorm,which injects generous newly emerging microbes into the atmosphere covering cities,adversely affects the air quality in built environments.However,few studies have examined the change of airborne bacteria during severe sandstorm events.In this work,we analyzed the airborne bacteria during one of the strongest sandstorms in East Asia onMarch 15th,2021,which affected large areas of China and Mongolia.The characteristics of the sandstorm were compared with those of the subsequent clean and haze days.The composition of the bacterial community of air samples was investigated using quantitative polymerase chain reaction(qPCR)and high-throughput sequencing technology.During the sandstorm,the particulate matter(PM)concentration and bacterial richnesswere extremely high(PM_(2.5):207μg/m^(3);PM_(10):1630μg/m^(3);5700 amplicon sequence variants/m^(3)).In addition,the sandstorm brought 10 pathogenic bacterial genera to the atmosphere,posing a grave hazard to human health.As the sandstorm subsided,small bioaerosols(0.65–1.1μm)with a similar bacterial community remained suspended in the atmosphere,bringing possible long-lasting health risks.

The Rise of Two‑Dimensional‑Material‑Based Filters for Airborne Particulate Matter Removal

Airborne particulate matter(PM)has been the leading contributor to air pollution,posing a substantial risk to human health,and effective filtration technologies are required.Two-dimensional(2D)materials,such as graphene,graphitic carbon nitride(g-C3N4),molybdenum disulfide(MoS2),and MXenes have emerged in recent years for PM filtration due to their exception-ally large specific surface area and unique electrical properties.Here,the most extensively used 2D materials for PM filtration followed by a summary of their fabrication methods and corresponding morphologies were introduced.Among them,the coating is the most cost-effective technique for achieving large-scale and quick fabrication.Electrospinning can effectively enhance filtration efficiency and reduce pressure drop by upgrading electrostatic force and lowering the fiber diameter.The initial and long-term performance of 2D-material-based filters was summarized.Among all 2D materials,GO is the most studied and shows the best performance by upgrading the dipole–dipole and electrostatic interaction between filters and PM.Future study is expected to explore various 2D materials beyond GO,to evaluate filtration efficiency for submicron PM at m/s level air velocity,and to extend the service life for potential applications.

A new pin-to-plate corona discharger with clean air protection for particulate matter removal

High concentration particulate matter(PM)has been a serious environmental problem in China and other devel-oping countries.Electrostatic-based purification technology is a method to remove airborne particles,and can reduce the energy consumption of ventilation fans in buildings because of its low pressure drop.In this study,we developed a new pin-to-plate corona discharger with particle-free external air protection to prevent particles polluting the surface of discharge pins.By using an optical microscope,we observed a certain number of parti-cles deposited on the non-protected(exposed pins)and few particles deposited on the protected pins after they operating for 3 weeks.We experimentally studied the long-term performances of the exposed and protected pins in single-pass PM removal efficiency and ozone production.The results showed that the protected pins produce less ozone and have higher breakdown voltage than the exposed pins.Experimental results indicated that the im-proved pin-to-plate corona discharger has better long-term performance and is safer than the exposed one.The results of the research can give an understanding of how to improve electrostatic-based purification technologies toward stable discharging for high removal efficiency of particles.