Lingjie Zeng

• PhD
• Professor (Assistant) at Tongji University

The global shift to cleaner cooking methods is gaining momentum, with many countries considering electricity as a viable alternative to reduce carbon emissions. Cooking raises temperatures and humidity in residential kitchens, impacting comfort and increasing energy consumption. This study employed scenarios with and without kitchen air conditionin...

Indoor volatile organic compound (VOC) concentrations are often dynamic because the ventilation and emission rates of VOC usually change. Adsorption filters used for air purification may operate with a capacity that fluctuates with unsteady VOC concentrations in buildings. Modeling the dynamic interactions between adsorption filters and indoor air...

Tunnels play a vital role in enhancing traffic flow and supporting public transportation systems. However, the discharge of polluted air and waste heat from vehicles passing through tunnels sig-nificantly raises the temperature inside, presenting challenges in terms of occupant comfort, tunnel safety, and infrastructure integrity. Therefore, ensuri...

Mould growth is a common problem in building envelopes. This issue is usually caused by poor design and construction of walls and results from the difference between indoor and outdoor climatic conditions. Mould spores produced by mouldy walls may diffuse into the air, thereby affecting indoor air quality and threatening occupant health. Therefore,...

Makeup air supply is critical for improving range hood performance and ensuring kitchen indoor air quality. The effect of a novel kitchen ventilation system with a cabinet-bottom air supply on the three evaluating indexes, namely the capture efficiency of the hood (CE), pollutant concentration in both the breathing zone (CB) and the space (CS), was...

Pressure drop is the key factor related to performance and energy consumption of fixed bed. However, the packing of cylindrical particles produces anisotropic gaps and an extremely complex airflow field and makes the formation mechanism of flow resistance undefined. This study conducted a comprehensive investigation on how such factors as the void...

Infectious disease departments in hospitals require pressure gradient to create unidirectional airflow to prevent the spread of contaminants, typically by creating active air infiltration through the difference between supply and exhaust air volumes. The door gap is the channel of air flow between rooms, so its height has an important influence on...

Ventilation systems designed for pollution removal in high-polluting workshops are usually ineffective due to the movement of workers. This work proposes a novel design method for direction air supply (DAS) system, which can protect personnel from exposure to gaseous contaminants during movement. A positioning system based on Kinect v2 for skeleton...

Activated carbon is one of the most commonly used porous materials for capturing gaseous pollutants from indoor air. To investigate the adsorption behavior of activated carbon in an indoor environment, the benzene adsorption capacities of 11 commercial activated carbons were measured in the concentration range of 0.05–6 ppmv (parts per million by v...

Internal thermal insulation composite system (ITICS) can be an important measure for the energy-saving retrofitting of buildings. However, ITICS may cause harmful effects on the hygrothermal performance of building envelopes. This work investigated the influence of the materials' hygric properties on the hygrothermal performance of a typical ITICS...

The discharge capacity of the range hood for cooking-related pollution under current exhaust airflow rate (EAR) standard of 300–500 m³/h is limited when cooking temperature near the smoke point of edible oil. This study endeavored to determine appropriate EAR for cooking temperature varies from 200 to 300 °C, which comprised smoke points of differe...

The indoor air quality (IAQ) of severely polluted toilets is associated with the transmission of diseases. Computational fluid dynamics (CFD) methods and experimental measurements were used to analyze the diffusion characteristics of pollutants. This study investigated the diffusion characteristics and normalized concentration of ammonia and hydrog...

The poor indoor air quality (IAQ) of severely polluted toilets is associated with increased risk of severe disease. This study aimed to evaluate the overall IAQ according to the contaminant removal efficiency, volume average concentration, and breathing zone control level. The characteristics of contaminant transmission in a non-flushing ecological...

A lifecycle model was established to explore the efficiency, economy, and greenhouse gas emissions of a non-phase-transition drying pyrolysis and mass conversion technology, based on the principle of lifecycle assessment. The evaluation scope included straw collection and transportation, drying and crushing, biomass pyrolysis, charcoal processing,...

The indoor environments of severely polluted toilets are associated with an increased risk of transmission of severe diseases. Enhancing the ventilation effectiveness can improve the indoor air quality (IAQ). The characteristics of pollutant transmission in a public toilet model were analyzed using a computational fluid dynamic program and were fur...

The effects of different human walking patterns on contaminant dispersion in residential kitchens were investigated through computational fluid dynamics simulation with the dynamic mesh method. A tracer gas experiment was performed to verify the feasibility and accuracy of the simulation method. Flow characteristics induced by human walking were mi...

The function of air curtain range hood in improving human exposure was investigated by conducting experiment and CFD simulation. The intake fraction was estimated to reflect the effect of the air curtain. Factors affecting human exposure, including the exhaust rate, heat source intensity, air supply angle, air supply velocity, and slot width of the...

A rotating disk with spokes was developed recently for its benefits in preventing grease accumulation. Parametric design of disk structure based on the particle capture efficiency and flow resistance has not been widely studied. This work performed experiments and computational fluid dynamic (CFD) simulations to analyze factors influencing the perf...

The adsorption filters used for cleaning indoor air are often made as a thin honeycomb skeleton filled with granular adsorbents. The resistance of honeycomb adsorption filters is one of the main parts for sizing the blowers. But currently no method is available to predict it accurately. Therefore, the pressure drop of honeycomb adsorption filters w...

In the scenarios of cooking oil fume exhaust in high-rise residential buildings and pollutants removal in industrial workshops, how to realize the exhaust uniformity is a problem. We discovered through our previous work that installing flow-guide devices at terminals within the exhaust system can greatly improve the exhaust uniformity of the system...

This study proposed a novel integrated design combing an air cleaner with the conventional exhaust hood for the improvement of indoor air quality in the residential kitchen. Airflow interaction between the exhaust confluence of the range hood and the strong momentum induced by air cleaner was investigated for this kind of compact configuration. The...

The well organized and sufficiently supplied make-up air is crucial to the removal of cooking oil fume (COF) particles in residential kitchens. Natural make-up air can also achieve similar influence, but it is usually ignored. This study investigated the effects of natural make-up airflow patterns through different openings on exhaust performance t...

This study proposed a control logic for a novel constant-air-volume (CAV) range hood. The Field Oriented Control vector was used to adjust the fan speed by comparing the current exhaust volume to the desired value. Experiments were conducted to test the air volume retention ability of the developed constant-air-volume range hood. Test results show...

Particle packing is widely applied in organic pollutant adsorption, catalytic reaction, biomass combustion, nuclear cooling, and other scenarios. Due to the complexity of the shape, the studies on the void fraction of the cylindrical particles are not as thorough as the spherical particles. This study investigated the influence of the filling rate,...

Studies have shown that the ventilation is of great significance in controlling the harmful cooking oil fume (COF) that is generated during cooking process and is mainly composed of thermal oxidation decomposition products produced by the chemical reactions of food and oil at high temperature. In order to fully understand the performance of the ven...

Flow characteristics induced by human walking and the effect of human walking on the performance of range hood in residential kitchen were investigated by performing transient CFD simulation with dynamic mesh method. Transient capture efficiency was used to evaluate the effect of human walking on range hood. Tracer gas experiment and visualization...

Void fraction of cylindrical particles greatly influences heat and mass transfer and resistance characteristics involved in the processes. The effect of the filling rate of cylindrical particles on the void fraction of the random loose packing (RLP) was studied through the experiments. Then, the discrete element method (DEM) was used to reproduce t...

Central flues are now commonly adopted in high-rise residential buildings in China for cooking oil fumes (COF) exhaust. Range hoods of all floors are connected to the central shaft, where oil fumes were gathered and exhausted through the outlet at the building roof. As households may cook and use their range hood at random periods, there is great u...

Exhaust system with one centralized fan and multiple terminals has been widely used for removing heat and pollutant. These systems share common problems include uneven pressure distribution within the system, insufficient exhaust at terminals, and the lack of control strategies when the condition of terminals varies. To solve those problems, an ope...

Air curtain range hood was developed recently for its beneficial effect on preventing spillage of pollutant and maintenance of good indoor air quality in kitchens. Orthogonal experiments were conducted in this study to investigate factors that affect the function of the air curtain range hood. The contaminant removal efficiency was measured and emp...

The emission standards of non-methane total hydrocarbon were tightened from 120 mg/m3 to 10 mg/m3 for Chinese industries in 2012. Despite the investment into environmental treatment, many factories have since been struggling to hit the emission reduction target. Emissions from various production processes have the characteristics of low concentrati...

Air cleaner is one of the most commonly used equipment for removing indoor air pollutants. Generally, when evaluating the performance of an air cleaner, it is assumed that air uniformly flows through the adsorption filter. However, in portable air cleaner the area of flow channel is usually much smaller than the area of the adsorption filter, resul...

An adsorption filter is the main functional component of a portable air cleaner. However, it is not easy to predict the adsorption efficiency of honeycomb adsorption filters using existing methods. Some of the required parameters are difficult to measure, in particular the hydraulic diameter of the adsorbent. In addition, some of the structural fac...

Terrorist attacks through building ventilation systems are becoming an increasing concern. In case pollutants are intentionally released in a building with mechanical ventilation systems, it is critical to localize the source and characterize its releasing curve. Previous inverse modeling studies have adopted the adjoint probability method to ident...

Using a radial jet at the outer edge of a circular exhaust hood can effectively reduce the velocity attenuation in front of the exhaust hood. The velocity distribution, especially the centerline velocity, is a key parameter in the effective design and use of an exhaust hood. In this paper, based on the derivation of the prediction formula of the su...

Using a radial active air jet ejected from the slot surrounding a circular exhaust hood opening can increase the air speed generated by the hood as well as achieve a larger capacity to exhaust pollutants. Critical parameters of the Aaberg hood have been identified to ensure the positive effect of the active jet. This paper proposed a novel type of...

Exhaust ventilation systems have been widely used in factories with multiple heat or pollutant sources. However, conventional “static” designs that fail to consider overlapping terminal ventilation demands result in oversized exhaust systems and high energy consumption. In this work, a novel approach was proposed to calculate dynamic exhaust demand...

Accurate prediction of the resistance of packed beds with cylindrical particles is critical for industrial applications. In this work, a series of experiments were performed to explore the effect of the morphology of cylinder on the pressure drop of airflow through packed beds. We used machined stainless-steel cylindrical particles with diameters o...

This paper proposes a push-pull airflow combined with a top draft hood to conduct local exhaust in a rubber workshop. Field measurements are carried out to investigate the characteristics of the emission source, while numerical simulation is performed based on the measurement to test the capture efficiency and to further optimize various parameters...

Chinese residents often use range hoods to exhaust cooking oil fumes (COF) and at the same time open inner/outer doors and windows for natural air supplement. Factors such as the layout of kitchens, the exhaust efficiency of range hoods, and the effect of natural air supplement, directly determine transmission characteristics of COF, which in turn...

Adsorption filters in air cleaners are usually produced as honeycomb structure filled with granular adsorbent, which can be seen as numerous parallel arranged fixed beds. In order to investigate if the friction factor correlations for packed bed can be used in adsorption filter, experimental study was conducted using adsorption filters filled with...

The design of a centralized cooking-fume exhaust system for high-rise residential buildings lacks the parameters related to cooking behavior, such as the coincidence factors. This study surveyed 12-, 14-, and 25-floor residential units by using a thermometer to obtain the continuous temperature profiles for study cooking behavior. Python was used t...

Fast locating the sources of hazardous pollutants in indoor environments is extremely important for ensuring indoor air quality and indoor environmental safety. Considering the timely and smooth implementation of the subsequent emergency measures, tracking hazardous sources in buildings with ventilation systems has a higher requirement on computati...

If hazardous gaseous pollutants are deliberately released in public buildings, it is necessary to detect them and warn promptly indoor occupants to evacuate. In this study, we propose a Markov-chain based probabilistic approach to optimize an indoor sensor network against a deliberately released contaminant and demonstrate it for a simple multi-zon...

The release of toxic airborne contaminants resulting from terrorist attacks on buildings can lead to disastrous consequences. To evaluate and reduce the effects of these emergencies, various methods and models have been developed in the past few years. Such work has provided effective tools for the building management system to do risk assessment o...

This paper illustrated an optimization method of sensor layout in air duct system, aiming at detecting toxicant before any catastrophic consequence in a bio-terrorist attack. The method was based on genetic algorithm (GA) with minimal emissions as objective function of the optimization procedure. In this paper, we discussed the impact of the number...

In recent years, the indoor occupants are being threatened by various risks related to the re-lease of hazardous contaminants. If the terrorists release a bio-chemical agent into an air duct system, the source must be promptly and accurately located and characterized to minimize the adverse impact of the contaminant releasing. In this work, we pres...

Filtering loads of outdoor PM2.5 for all province capital of China are determined with the method of un-guarantee days. Filtering Concentration Days(FCD) is proposed with the analogy of the CDD and HDD. Based on PM2.5 concentrations dynamic data and the base concentration, the FCDs of all province capital are calculated. The relationship between FC...

This paper ilustrated a source identification method in air duct system，aiming at detecting contaminant source within a short period of time after a bio-terorist atack.The method was based on genetic algorithm (GA)with minimal diference betwen calculated concentration and measured concentration as fitnes function.We established a database of calcul...

When a chemical or biological agent is suddenly released into a ventilation system, its dispersion needs to be promptly and accurately detected. In this work, an optimization method for sensors layout in air ductwork was presented. Three optimal objectives were defined, i.e. the minimum detection time, minimum contaminant exposure, and minimum prob...

When a chemical or biological agent is suddenly released into ventilation ducts, agent concentration along the whole ductwork should be promptly and accurately determined. In this work, an advection-diffusion model was suggested to calculate the agent transport in the air ducts. A node model was constructed for the agent dispersion at the duct junc...

If a CWA or BWA agent is released into ventilation duct, fast calculating the concentration distribution of the whole ductwork is a crucial method to minimize the adverse impact of contaminant release. In this work, a general model which taking into account both advection-diffusion effects and the bulk mixing assumption at cross junctions for predi...