Zhi Gao

Nanjing University | NJU · Department of Architecture

Cool roofs play a significant role in mitigating urban heat islands, improving indoor thermal comfort, and saving energy. In recent years, with advances in the manufacturing of nanophotonics and metamaterials, researchers have developed super cool roofs where the surface temperature remains below the air temperature in direct daylight and temperatu...

The Covid-19 virus can spread rapidly in the air and cause the epidemic to rage around the world. This study takes a typical office as the research object and proposes four different partition settings to suppress the spread of the virus in the air based on displacement ventilation. And these strategies are verified by DPM model simulations of two...

Three-dimensional computational fluid dynamics (CFD) simulations based on the discrete phase model were performed to explore the spatial distribution of traffic-related PM2.5 in summer and winter in nine typical neighborhoods (300 × 300 m) established through investigating realistic samples in Nanjing, China. These cases have different building typ...

The transformation of urban and building design into green development is conducive to alleviating resource and environmental problems. Building design largely determines pollutant emissions and energy consumption throughout the building life cycle. Full consideration of the impact of urban geometries on the microclimate will help construct livable...

After decades of development, intelligent buildings have been widely used in today's building business, and their definition and scope are constantly updated. However, compared with green buildings, there are fewer and immature standards for intelligent buildings both in China and around the world. This paper focused on the evaluation standards of...

The deterioration of the urban environment is a problem which has captured the attention of governmental departments and researchers, who are committed to improving the urban environment from the perspective of optimizing urban morphology. Although many researchers have applied computational fluid dynamics (CFD) plug-ins to study the problems of ur...

Many multi-story residential buildings have been built in villages to improve the living quality of rural residents in China. Therefore, village morphology has dramatically changed compared to the past. Since northern China continues to suffer from environmental problems, improving village ventilation by optimizing village morphology is essential f...

The frontal area index (FAI) is an essential parameter for assessing underlying roughness and analyzing urban ventilation corridors. Since the early 1990s, FAI has gradually gained prominence in the urban environmental field. Several FAI calculation methods using various names have been proposed over the last three decades under different research...

The deterioration of the urban environment has captured the attention of governmental departments and research institutions, which aim to improve the urban environment from the perspective of optimizing urban morphology. Although ideal building arrays and residential building morphologies have been previously studied, research on the relationship b...

The influence of roadside morphology and the movement of vehicles on street canyon ventilation is important, but their coupling effect is still unclear. This study aimed to determine the best structural design for roadside buildings while considering moving vehicles’ effect on ventilation. The morphologies examined were podium, cantilever, rain she...

Indoor air quality (IAQ) is vital to human health, comfort, performance, and wellbeing as people typically spend over 80% of their time indoors. The indoor pollutants people are exposed to originate from both indoors and outdoors. In order to devise an energy-efficient and cost-effective approach to improve IAQ, it is necessary to consider strategi...

The morphology of urban residential blocks in China, which is strictly affected by regulations, can potentially improve or deteriorate microclimates. This paper first proposes a framework for identifying typical residential block typologies using Nanjing as an example. A thorough investigation, consisting of 114 samples, was conducted, and 18 typic...

Forty-two scenarios were simulated, using the OpenModelica platform, to study the impact of different factors on the transport of kitchen pollutants. In summer, an increase in outdoor wind velocity can improve natural ventilation and reduce kitchen pollutant concentrations. In winter, natural ventilation is mainly driven by thermal pressure, and ou...

COVID-19 has forced people to spend more time working and studying at home; in particular, people who share an apartment stay in their respective bedrooms almost all day. This study investigated the impact of ventilation modes on the indoor air quality (IAQ) of 24-hour occupied bedrooms and provided ventilation suggestions for people who stay in th...

This study investigates the effect of urban vegetation on thermal comfort in a neighbourhood of Lahti (Finland) by means of modeling simulations performed with the Computational Fluid Dynamics-based and microclimate model ENVI-met. A scenario without vegetation and the current one (with vegetation) are considered to assess the effects of vegetation...

To gain further insight into the ventilation at urban street intersections, this study conducted 3D simulations of the ventilation at right- and oblique-angled intersections under eight wind directions by using the Reynolds-averaged Navier–Stokes (RANS) κ-ε turbulence model. The divergent responses of ventilation and pollution concentration for the...

As more megacities emerge owing to urbanization and industrialization, the subway has become the main public transportation mode worldwide, providing punctuality and convenience. The subway environment, including its ventilation, thermal comfort, air quality, and energy consumption, remains an area of great focus for scientists and passengers. In a...

Focusing on the effect of street morphology on the ventilation efficiency, this paper presents 3D computational fluid dynamics (CFD) simulations of airflow and pollutant dispersion within urban-like three-way intersections, four-way intersections and roundabouts. The steady-state Reynolds-averaged Navier-Stokes (RANS) k-ε turbulence model is adopte...

To improve ventilation efficiency and reduce pollution concentration in urban spaces, eco-strategies, including greening, have been suggested. However, there is still very little evidence to assert the benefits of such greening options, particularly at urban street intersections. Therefore, in this work, air flow and pollutant dispersion within urb...

To conduct a more comprehensive evaluation regarding the correlations between urban form, microclimate and energy performance of buildings, this study investigates eight generic residential district prototypes in Nanjing, China. Cases are characterized based on form indices such as the floor area ratio (FAR), surface area ratio (SAR) and mean sky v...

The present work aims at studying the annual stack ventilation of solar chimney in multi-storey buildings and evaluating the ventilation potential. A simulation workflow coupling Honeybee and RhinoCFD, performance simulation tools on design platform, is proposed to calculate the hourly ventilation rate of chimney driven by solar energy. Then the ef...

This paper numerically investigates the ventilation of residential streets bounded by buildings of different forms. The aim is to provide suggestions for the design of environmentally sustainable urban streets in residential areas. Four representative building form variations along residential streets in Nanjing, located in the Yangtze River Delta...

With the acceleration of urbanization, subway has gradually become an effective means of transportation to solve urban traffic congestion. The application of computer simulation technology in subway station is more and more frequent. And Computational fluid dynamics simulation (CFD) is an indispensable part of it. This paper summarizes the applicat...

A modular-based Green Design Studio (GDS) platform has been developed in this study for fast and accurate performance analysis for early stage green building design. The GDS platform aims to simplify the design and analysis process by embedding performance parameters into design elements in modules and employing near-real-time model for whole build...

This paper is devoted to the assessment of urban greening effects on two important ecosystem services, i.e., air quality and CO 2 storage, including the corresponding economic impacts in a real urban area, i.e., a district located in the Mediterranean city of Lecce (southern Italy). Two tools were employed, i-Tree Canopy and the computational fluid...

This paper presents a conceptual framework that looks at photovoltaic systems in synergy with ecosystem services. The focus is to connect business success with social and ecological progress based on the operative concept of multifunctional land use. Such an approach attempts to harmonise the needs of the industrial processes of photovoltaic system...

The accurate identification of the characteristics of pollutant sources can effectively prevent the loss of human life and property damage caused by the sudden release of harmful chemicals in emergency situations. Machine learning algorithms, artificial neural network (ANN), support vector machine (SVM), k-nearest neighbour (KNN) and naive Bayesian...

In recent years, several ventilation indices have been proposed and applied to assess the efficiency of “urban outdoor ventilation”, i.e. the ability of an urban area to dilute pollutants, heat and moisture by exchanging air between inside and above of the urban canopy. Here, focusing on the pollutant dispersion, the definition of 13 ventilation in...

As near-ground ozone is toxic to the human body，a number of standards have been promulgated by many countries and regions to limit indoor and outdoor ozone concentrations． The stipulation and development of indoor and outdoor ozone limit concentration standards at home and abroad are introduced in this paper． Evaluation indexes and methods in China...

This paper investigates the correlation between street morphology and thermal environment of six street models representing the central morphology of Barcelona (Spain), Berlin (Germany), London (UK), New York (US), Nanjing (China) and Paris (France). The morphology is first characterized through morpho- logical indices (i.e. opening and closing rat...

In the context of urbanization, research on urban microclimate and thermal comfort has become one of the themes of eco-city design. Sky view factor (SVF), one of the parameters of urban spatial form, combines multiple morphological information, such as plane opening, aspect ratio, and building density and has an important impact on the urban microc...

M.V.) † Equal contribution to this work. Abstract: This paper is devoted to the analysis of the impact of changes in olive urban forests affected by Xylella fastidiosa on ecosystem services. The focus is on microclimate and thermal comfort evaluated by two indices: the temperature of equivalent perception (TEP) and the predicted mean vote (PMV), wh...

Ozone has become one of the most serious air pollutants in China in recent years. Since people spend most of their time indoors, the ozone in the indoor environment could be a major factor affecting the occupants' health. The indoor ozone in residential buildings mainly comes from two sources: outdoor atmosphere and indoor ozone produced by electri...

As a strong oxidizing gas, ozone can damage the human respiratory tract and cardiovascular system. Aside from ambient outdoor ozone that enters buildings, indoor ozone emission devices (IOEDs) such as disinfectors, air purifiers, and printing devices are the primary source of indoor ozone. This review briefly presents the types and ozone emission m...

This paper discusses current state-of-the-art features of the “plant evaluation model”, a framework which, starting from the representation of vegetation and its effects in microclimate models, defines a number of indices which can be employed for the evaluation of outdoor microclimate in terms of thermal environment and comfort in the urban enviro...

Particulate matter (PM) is one of the major air pollutants in China. Traffic-related microenvironments are the typical scenarios exposed to high PM concentrations. This paper investigates the personal exposure to PM during commuting in Nanjing in four transportation modes, i.e. subway, bicycle, bus and walking. The measurements were conducted in a...

The surface of the human body is abundant in organic compounds containing unsaturated carbon -carbon bonds，squalene and the fatty acids in skin oil，covering the human body，which can readily react with ozone. Ozone-initiated chemical reactions produce volatile organic compounds （VOCs），semi-volatile organic compounds （SVOCs），and secondary organic aer...

Urban outdoor ventilation and pollutant dispersion have important implications for urban design and planning. In this paper, two urban morphology parameters, i.e. the floor area ratio (FAR) and the building site coverage (BSC), are considered to investigate their quantitative correlation with urban ventilation indices. An idealized model, including...

This study quantifies the influence of green spaces on microclimate and PM10 concentration in a typical residential district of Nanjing (China) by employing the CFD-based and microclimate model ENVI-met 4. Five green indices, related to quantity and structure of vegetation, are employed to investigate the impact of different types (grass, shrub and...

The Air quality in student dormitories can have a major impact on the health of millions of students in China. This study aims to investigate the ventilation and air quality in student dormitories. Questionnaire survey was conducted in eight dormitory buildings and field measurements were conducted in one dormitory during the summer in Nanjing. The...

This study numerically investigates the influence of different vegetation types and layouts on microclimate and air quality in residential districts based on the morphology and green layout of Nanjing, China. Simulations were performed using Computational Fluid Dynamics and the microclimate model ENVI-met. Four green indices, i.e., the green cover...

Ozone is a reactive gas that can have negative health effects on human. Building materials can be significant sinks for indoor ozone, owing to the irreversible heterogeneous reactions between ozone and material surfaces. Therefore, the ozone removal on material surfaces is crucial for evaluating indoor ozone concentrations and human exposure. This...

Green space offers great benefits to urban environment quality. There has been lots of research on urban green space planning and landscape ecological effect, however, few quantitative work has been carried out on its microclimate impact. The current relevant studies have been more focused on greening quantity, with less concern for greening struct...

In this paper, three realistic high-rise residential districts in Jinan are selected.to study the relationship between the internal morphology and ventilation performance. The typical positions are tested on the basis of CFD simulation and field measurement. Result shows that it is effective to improve the residential district ventilation efficienc...

This paper discusses the correlation between the morphological characteristics of urban public plots and ventilation performance. By keeping the floor area ratio (FAR) constant and changing the building site coverage (BSC) and building location as morphological parameters in the plots, nine idealized building configurations are established. The spa...

Both outdoor and indoor ozone concentrations have negative health effects on human. This paper proposes an artificial neural network to estimate the outdoor ozone concentrations and a mass balance model tool to estimate indoor ozone concentrations. The prediction of outdoor and indoor ozone concentration levels is of great significance for people's...

Street canyons are vulnerable to air pollution mainly caused by vehicle emissions, which are therefore closely related to pedestrians’ health. Previous studies have showed that air quality in street canyons is associated with street morphology, though the majority of them have focused on idealized street models. This paper attempts to investigate t...

This paper explores the method of assessing regional spatial ventilation performance for the design of residential building arrangements at an operational level. Three ventilation efficiency (VE) indices, Net Escape Velocity (NEV), Visitation Frequency (VF) and spatial-mean Velocity Magnitude (VM), are adopted to quantify the influence of design va...

Outdoor thermal comfort indices are used to characterize the thermal sensation of people in complex environmental conditions directly, which is important in the thermal comfort research. A review of the outdoor thermal comfort indices was made after consulting literatures and in the present paper, the indices were divided into three categories acco...

Outdoor particles can penetrate through wall assemblies and influence the indoor air quality (IAQ). In this study, a computational fluid dynamics (CFD) model was developed for predicting the particle penetration through wood-framed residential wall assemblies. The model included a simplified approach to account for the particle loss due to the fibe...

A test procedure was developed and verified to measure the airborne concentrations of particles of different sizes (0.5-20 μm) within the vicinity of a dropped container when a significant portion of the tungsten oxide powder (simulating uranium oxide) is ejected from the container. Tests were carried out in a full-scale stainless steel environment...

The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50%, and 70% RH). The "green" materials contained recycled materials and were friendly to environment. A dynamic dual-c...

Outdoor pollutants, such as ozone, can penetrate into the indoor environment through the wall assemblies and influence the indoor air quality (IAQ). Ozone can also react with chemical compounds (i.e., d-limonene, α-pinene, β-pinene, styrene, etc.) within the wall assemblies to create secondary emissions causing IAQ concerns. This study developed a...

An “Exposure Reduction Effectiveness” index is proposed to quantify the performance of room air cleaners based on their capability of reducing occupants' exposure to pollutants of interest. The index has advantages over existing index such as CADR. It is applicable to both room average and local breathing zones, and can be used to compare air clean...

This paper describes a new experimental method for determining the initial concentrations of emittable volatile organic compounds (VOCs) from building materials and sorption isotherms for individual VOCs (IVOCs), which are required for modeling the VOC emission rates of building materials and assemblies. The method is also useful for the rapid scre...

According to the Freedonia Group, the consumer market for air cleaners, ranging from portable (room) to duct mounted (whole house) devices, grew 34% over a 5-year period to reach $395 million in 2004, and is estimated to reach $515 million by 2008. Homeowners, however, have only limited information available regarding their performance, especially...

With the rapidly growing consumer markets for air cleaners, product performance evaluations are needed to assist the selection by consumers as well as design and manufacturing. VOCs (and odors) and particulates are two major contaminant categories for which many air cleaners are claimed to have good removal efficiency. However, no standard method f...

A mathematical formulation was developed including an objective function that minimizes the cumulative exposure of occupants to pollutants under the constraints of pollutant dispersion pattern, evacuation paths, and their capacities. The formulation included airflow and pollutant dispersion models and optimization algorithms for evacuation planning...