Recent advances in modeling turbulent wind flow at pedestrian-level in the built environment.

Pressing problems in urban ventilation and thermal comfort affecting pedestrians related to current urban development and densification are increasingly dealt with from the perspective of climate change adaptation strategies. In recent research efforts, the prime objective is to accurately assess pedestrian-level wind (PLW) environments by using different simulation approaches that have reasonable computational time. This review aims to provide insights into the most recent PLW studies that use both established and data-driven simulation approaches during the last 5 years, covering 215 articles using computational fluid dynamics (CFD) and typical data-driven models.

Comparative analysis on indoor and outdoor thermal comfort in transitional seasons and summer based on multiple databases: Lessons learnt from the outdoors.

In environments with similar physical parameters, thermal comfort and sensation feelings may differ indoors and outdoors. How indoor and outdoor thermal perception differ from each other remains unclear. This study compared and discussed 29,536 field survey data, including 19,191 sets of indoor data, and 10,345 sets of outdoor data, covering five Köppen climate zones during transitional seasons and summer.

Probable cross-corridor transmission of SARS-CoV-2 due to cross airflows and its control.

A COVID-19 outbreak occurred in May 2020 in a public housing building in Hong Kong - Luk Chuen House, located in Lek Yuen Estate. The horizontal cluster linked to the index case' flat (flat 812) remains to be explained. Computational fluid dynamics simulations were conducted to obtain the wind-pressure coefficients of each external opening on the eighth floor of the building.

Spread of SARS-CoV-2 aerosols via two connected drainage stacks in a high-rise housing outbreak of COVID-19.

Vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) along a vertical column of flats has been documented in several outbreaks of coronavirus disease 2019 (COVID-19) in Guangdong and Hong Kong. We describe an outbreak in Luk Chuen House, involving two vertical columns of flats associated with an unusually connected two-stack drainage system, in which nine individuals from seven households were infected. The index case resided in Flat 812 (8th floor, Unit 12), two flats (813, 817) on its opposite side reported one case each (i.

Preparation of Stable Phase Change Material Emulsions for Thermal Energy Storage and Thermal Management Applications: A Review.

Thermal energy storage (TES) is an important means for the conservation and efficient utilization of excessive and renewable energy. With a much higher thermal storage capacity, latent heat storage (LHS) may be more efficient than sensible heat storage. Phase change materials (PCMs) are the essential storage media for LHS.

Transient tracer gas measurements: Development and evaluation of a fast-response SF measuring system based on quartz-enhanced photoacoustic spectroscopy.

This study aims to develop a fast-response sulfur hexafluoride (SF ) measuring system, and evaluate its performance in tracer gas measurements for studying transient airborne contaminant transport. The new system is based on a quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor using a quantum cascade laser. Transient SF tracer gas measurements were carried out in an environmental chamber with an instantaneous source using both the QEPAS system and a traditional commercial instrument.

Dynamic thermal pleasure in outdoor environments - temporal alliesthesia.

Thermal comfort research has been historically centred around the concept of "thermal neutrality". Thermal neutrality originates from the steady-state indoor environment and is increasingly questioned when used to define the optimum sensation in outdoor environments. This calls for new criteria, designated for non-steady state and dynamically evolving outdoor settings.

Air infiltration induced inter-unit dispersion and infectious risk assessment in a high-rise residential building.

Identifying possible airborne transmission routes and assessing the associated infectious risks are essential for implementing effective control measures. This study focuses on the infiltration-induced inter-unit pollutant dispersion in a high-rise residential (HRR) building. The outdoor wind pressure distribution on the building facades was obtained from the wind tunnel experiments.

Evaluation of pedestrian wind comfort near 'lift-up' buildings with different aspect ratios and central core modifications.

Owing to the void space at lower heights, lift-up buildings have high building permeability at ground level and subsequently improve the air circulation in congested urban areas. Despite this advantage, the lift-up design has been sparsely adopted for buildings in urban areas partly because of the lack of understanding of the combined effects of building dimensions and lift-up design on the surrounding pedestrian level wind (PLW) field. Therefore, this study aims to investigate the influence of lift-up buildings with different aspect ratios (height/width) on the surrounding PLW field and pedestrian wind comfort level.

On-site measurement of tracer gas transmission between horizontal adjacent flats in residential building and cross-infection risk assessment.

Airborne transmission is a main spread mode of respiratory infectious diseases, whose frequent epidemic has brought serious social burden. Identifying possible routes of the airborne transmission and predicting the potential infection risk are meaningful for infectious disease control. In the present study, an internal spread route between horizontal adjacent flats induced by air infiltration was investigated.

Characteristics of physical blocking on co-occupant's exposure to respiratory droplet residuals.

Existed evidences show that airborne transmission of human respiratory droplets may be related with the spread of some infectious disease, such as severe acute respiratory syndrome (SARS) and H1N1 pandemic. Non-pharmaceutical approaches, including ventilation system and personal protection, are believed to have certain positive effects on the reduction of co-occupant's inhalation. This work then aims to numerically study the performances of mouth covering on co-occupant's exposure under mixing ventilation (MV), under-floor air distribution (UFAD) and displacement ventilation (DV) system, using drift-flux model.

Transient CFD simulation of the respiration process and inter-person exposure assessment.

It is known that the person-to-person spreading of certain infectious diseases is related with the transmission of human exhaled air in the indoor environments, and this is suspected to be the case with the severe acute respiratory syndrome (SARS) outbreak. This paper presents the numerical analysis of the human respiration process and the transport of exhaled air by breathing, sneezing, and coughing and their potential impact on the adjacent person in a modeled room with displacement ventilation. In order to account for the influence of the thermal plume around the human body, a three-dimensional computational thermal manikin (CTM) with an accurate description of body geometry was applied.