Range Hood Research Articles

Using the principle of dynamic temporal separation to determine the range hood direct capture efficiency

Using the principle of dynamic temporal separation to determine the range hood direct capture efficiency

Measured air quality impacts after teaching parents about cooking ventilation with a video: a pilot study.

Cooking-related emissions contribute to air pollutants in the home and may influence children's health outcomes. In this pilot study, we investigate the effects of a cooking ventilation intervention in homes with gas stoves, including a video-based educational intervention and range hood replacement (when needed) in children's homes. This was a pilot (n = 14), before-after trial (clinicaltrials.gov #NCT04464720) in homes in the San Francisco Bay Area that had a school-aged child, a gas stove, and either a venting range hood or over-the-range microwave/hood. Cooking events, ventilation use, and indoor air pollution were measured in homes for 2-4 weeks, and children completed respiratory assessments. Midway, families received this intervention: (1) education about the hazards of cooking-related pollutants and benefits of both switching to back burners and using the range hood whenever cooking and (2) ensuring the range hood met airflow and sound performance standards. The educational intervention was delivered via a video developed in conjunction with local youth. We found substantially increased use of back burners and slight increases in range hood use during cooking after intervening. Even though there was no change in cooking frequency or duration, these behavior changes resulted in decreases in nitrogen dioxide (NO2), including significant decreases in the total integrated concentration of NO2 over all cooking events from 1230 ppb*min (IQR 336, 7861) to 756 (IQR 84.0, 4210; p < 0.05) and NO2 collected on samplers over the entire pre- and post-intervention intervals from 10.4 ppb (IQR 3.5, 47.5) to 9.4 (IQR 3.0, 36.1; p < 0.005). There were smaller changes in PM2.5, and no changes were seen in respiratory outcomes. This pilot before-after trial evaluated the use of a four-minute educational video to improve cooking ventilation in homes with gas stoves and one or more school-aged children. Participant behavior changed after watching the video, and there were decreases in indoor air pollutant concentrations in the home, some of which were significant. This brief video is now publicly available in English and Spanish (wspehsu.ucsf.edu/projects/indoor-air-quality), and this provides suggestive evidence of the utility of this simple intervention, which could be particularly beneficial for households that have children with asthma.

Air pollutant exposure concentrations from cooking a meal with a gas or induction cooktop and the effectiveness of two recirculating range hoods with filters

This study compares air pollutant concentrations resulting from cooking with gas or induction cooktops, with or without either of two recirculating range hoods with filters. A meal of pasta, plant-based “meat” sauce and stir-fried broccoli was cooked three times for each cooktop and hood combination in a 158 m3 room. Time-resolved measurements were made of nitrogen oxides (NOX), carbon dioxide (CO2), size-resolved particles, and speciated volatile organic compounds (VOCs) during cooking and 30 minutes after cooking. Cooking with induction used half as much energy, produced no discernible NOX, and significantly reduced ultrafine particles (UFP, diameter < 100 nm) and CO2 compared to gas cooktops. Induction produced statistically higher PM2.5 when calculated using size-resolved particle measurements from one pair of instruments, but the difference was not discernible when calculating from another pair. With gas cooktops, roughly half of the PM2.5 was in particles smaller than 0.3 μm and thus below the lower quantitation threshold for many optical particle instruments; optical devices may thus substantially under-report PM2.5 from gas cooking. VOCs did not significantly differ between gas and induction. Both recirculating range hoods substantially reduced all particle sizes when cooking with either fuel, and the reductions were larger for gas cooking. One of the range hoods also substantially lowered some of the VOCs.

New Makeup Air Method through Ceiling for Kitchen Ventilation in Severely Cold Regions and Its Effect on Air Environment

Severely cold weather reduces the willingness of residents to open windows while cooking. This results in an insufficient replenishment of makeup air and a reduction in the range hood discharge capacity. For an effective trade-off between indoor air temperature maintenance and air quality aggravation in winter, a new makeup air supply method (ceiling makeup air) was proposed and established both experimentally and numerically. The improvements in the kitchen air environment during cooking were studied through experimental tests and CFD simulations, considering different makeup air arrangements. The results reveal that the ceiling makeup air scheme can significantly reduce the concentration of PM2.5 compared with the cracks makeup air scheme (wherein the kitchen window and door are closed). Moreover, it increased the indoor temperature by over 11.9 °C compared with the open window makeup air scheme. The average relative error between the experimental and simulated data was within 6.1%. Among the considered factors, the size of the air inlet had the largest impact. This was followed by the layout, size, and shape of the ceiling inlets. The ceiling makeup air scheme demonstrated the potential for improving residential kitchen air environments in severely cold regions.

A study of quantifying the influence of kitchen human activity on indoor air quality dynamics

Indoor air quality (IAQ) is increasingly recognised as one of the critical factors influencing human health, particularly given the amount of time people spend indoors. This study investigated the impact of real-life kitchen human activity (KHA) on IAQ. We used low-cost sensors to measure real-time concentrations of smoke, carbon monoxide (CO), and particulate matter (PM10 and PM2.5) in the kitchen of a household with three adults, analysing KHAs by dividing them into five categories. The fixed effect model was employed to analyse the data, explaining the impact of different KHAs on IAQ. The results showed that compared to other KHAs, using the gas stove had the greatest impact on IAQ, with average increases of 13% in smoke, 24.4% in CO, 9.8% in PM10, and 5.34% in PM2.5. The study also found that without windows and with insufficient ventilation, only using the range hood cannot effectively and obviously reduce PM levels. These findings highlight the need for comprehensive IAQ management strategies and further research. Despite its limitations, this study also validated the potential of low-cost sensors in IAQ monitoring.

Improving kitchen thermal comfort in summer based on optimization of airflow distribution

To quantitatively analyze the comfort of kitchen environment, this paper presents a thermal comfort analysis method for kitchen with air-conditioned range hood. It corrects the deficiency in the original comfort formula involving humidity, thereby reasonably quantifying the impact of the cooling airflow from air-conditioning, including humidity, on kitchen thermal comfort. By adjusting the structural parameters of the air conditioning system, the airflow distribution in the kitchen space during summer has been optimized, thereby further enhancing its thermal comfort. This method employs Fluent analyses and its User-Defined Functions (UDF) to analyze the indoor flow field, temperature, humidity, and the distribution of PMV-PPD within the kitchen equipped with air-conditioned range hood. Additionally, experimental data are applied to validate the accuracy and effectiveness of the simulation model. The results indicate that under high temperature climate conditions in summer, air-conditioned range hood significantly enhances the thermal comfort of kitchen environment during cooking. Moreover, optimal thermal comfort for both the kitchen space and local respiratory area of the human body is achieved when the air supply angle is set at 45°, the air conditioning outlet flow rate is 5.5 m3/min and the air supply temperature is set at 21 °C. Compared to the initial operating conditions, Human thermal sensitivity weighted PMV decreased by 98.17 %, and the weighted PPD decreased by 82.07 %. This study provides valuable insights for the design and operation of air-conditioned range hoods, contributing to improved thermal comfort and energy efficiency in residential kitchens.

Evaluation of the air quality and the thermal comfort in the kitchen fume environment under the fresh air supplement

Kitchen cooking particles can severely deteriorate indoor environment, aggravating the risk of cardiovascular and cerebrovascular diseases, as well as respiratory diseases. In view of the severe hazard of cooking particles to human health, this paper numerically studies the trajectory and deposition of the cooking particles in the kitchen environment based on a numerical model. Also, quantitative evaluations for the air quality and thermal comfort are performed, hoping to provide a useful reference for the control of kitchen air pollution. Firstly, a kitchen environment simulation model is established based on Fluent. A post-processing UDF program for evaluating the effectiveness of fume absorption is developed. The reliability of the numerical model is verified by comparing the results of the fume concentration with those by the cooking experiments. Using this numerical model, the fume extraction effectiveness of the range hood under different velocities of the fresh air is analyzed comprehensively, including particle trajectory, air age, temperature, PMV (Predicted Mean Vote), and PPD (Predicted Percentage of Dissatisfied) indicators. Results have shown that high speed of the fresh air can cause a strong blowing sensation, deteriorating indoor air quality. The PMV and PPD values around the human body show a parabolic trend. Generally, the relatively low fresh air speed can achieve satisfactory air quality and thermal comfort while saving energy consumption.

Performance analysis of range hoods with different exhaust air volumes

Performance analysis of range hoods with different exhaust air volumes

Numerical study of the impact of make-up air in a residential kitchen on the heating and cooling demands of ULEBs

Ventilation significantly impacts energy consumption in ultra-low-energy buildings (ULEBs). However, in Chinese residential kitchens, the influence of mechanical ventilation formed by range hoods and make-up air systems on energy consumption has received limited attention. This study assesses the heating and cooling demands in ULEBs resulting from kitchen make-up air across different climate zones in China. The results reveal that in natural make-up air mode, there is a substantial rise in annual heating demand in cold and severe cold zones and a notable increase in annual cooling demand in hot summer and warm winter as well as hot summer and cold winter zones. Additionally, the natural make-up air mode often poses challenges in maintaining a satisfactory thermal environment in kitchens during both heating and cooling seasons. Conversely, the mechanical make-up air mode, especially with pretreatment of outdoor air to ensure thermal comfort in kitchens, significantly elevates both annual heating and cooling demands, making it hard for the building to meet the ULEB specifications, particularly in cold and severe cold zones. Furthermore, despite a generally small increase in annual cooling demand, the percentage rise in heating demand often exceeds the ULEB limits, ranging from 12.0% to 36.0%, depending on the climate zone.

Human thermal comfort in kitchen with different ventilation modes based on a coupled CFD and thermoregulation model

Kitchen ventilation is crucial in effective removal of pollutants and heat in the enclosed kitchens to ensure occupants' thermal comfort and health. However, mechanical ventilation systems, such as range hoods and make-up air systems, often create non-uniform and dynamic thermal conditions, posing challenges for traditional comfort metrics. In response, this study utilizes Computational Fluid Dynamics (CFD) coupled with a human thermoregulation model to evaluate the thermal comfort across various kitchen ventilation modes. Our findings reveal significant non-uniformity in indoor thermal environments surrounding the occupant, with differences in ambient temperature reaching 14.2 °C and air velocity up to 0.64 m/s, directly impacting occupants' comfort. Notably, mechanical ventilation employing air curtains for make-up air surpasses natural methods, enhancing overall thermal sensation by 42 % and reducing mean drought rates by 70 % during winter. Additionally, ceiling supply systems improve upper body comfort in summer, offering personalized thermal comfort solutions, and achieves optimal thermal comfort conditions at a make-up air temperature of 25 °C. This research contributes valuable insights into selecting appropriate ventilation strategies for residential kitchens, thereby promoting occupants' well-being and health.

Controllable baffle-type exhaust-hood in home kitchen

In order to reduce the pressure of the central smoke shaft in high-rise apartments, a controllable baffle-hood was proposed to improve the smoke removal efficiency without increase the exhaust airflow rate in the kitchen. A series of baffle-type hoods with various locations and shape of panel were explored to evaluate the pollutant removal efficiency. The results showed that the baffle design reduces pollutant concentration by 8%–71% and lowers temperature by 0.8 °C–2.0 °C compared to conventional range hoods. A power function relationship was found between pollutant concentration and air velocity at cross-sectional of inlet. The panel is still a simple and useful technology in the home kitchen, if it can solve the convenience of cooking operations.

Feasibility study on improving the performance of the kitchen exhaust system by integrating a supercharging fan

Connecting a supercharging fan (SF) in series with the range hood is a practice way to better discharge the harmful oil fumes in residential kitchens, but a poor match SF may fail to help exhaust and even cause additional noise issues. This study aims to clarify how the SF rotation speed affects the operation of the existing range hood and explore the possible noise advantages of the series exhaust system. The computational fluid dynamics method was used to simulate the aerodynamic performance and internal flow of different exhaust systems. Analysis revealed that the system's exhaust capability can only be improved when the SF rotates fast enough, generating sufficient pressure rise to overcome its own flow resistance. Performance leading over the entire flow range is achieved when the SF rotates at 2500 rpm, where the pressure rise in the actual working range is increased by nearly 40%. These performance enhancements buy a rotational speed reduction of almost 300 rpm for the hood fan when the system's pressure remains unchanged. The airflow in the range hood thus decelerated by 14.5–18.2%, and the undesired reverse flows were also inhibited. The results obtained by full-scale kitchen experiments show that the sound pressure level of the series system was 0–1 dB lower than that of the original range hood in the same flow rate, and this decrement is maximum to 2 dB by inducing sound-absorbing treatment on the SF. This study provides preliminary guidance for integrating an SF in a range hood exhaust system, offering a novel view of its benefits and challenges.

Experimental evaluation of the impact of ventilation on cooking-generated fine particulate matter in a Chinese apartment kitchen and adjacent room

Cooking is one of the major contributors to indoor pollution. Fine particulate matter (PM2.5) produced during cooking commonly mix into adjacent rooms and elevates indoor PM2.5 concentrations. The risk of human exposure to cooking-generated PM2.5 is mainly related to the exposure duration and particulate matter (PM) concentration. The PM2.5 concentration is influenced by cooking methods and ventilation patterns. Range hoods and open windows are conventional strategies for lowering the concentration of cooking-generated particles. To decrease PM emissions, kitchen air supply systems have been proposed, providing alternative possibilities for kitchen ventilation patterns. The effects of cooking methods, air supply systems, range hoods, and windows on PM2.5 concentrations must be analyzed and compared. To understand and provide advice on reducing exposure to PM2.5 due to cooking activities, we measured the PM2.5 mass concentration in a kitchen and adjacent room during cooking. The identified factors, including cooking method, range hood use, window status, and air supply system, were varied based on orthogonal design. The delay time between the PM2.5 peak in the kitchen and that in the adjacent room was determined. The degree of exposure risk for cooking-generated PM2.5 was evaluated using the mean exposure dose. The results indicated that the mean PM2.5 mass concentration in the kitchen ranged from 22 to 2296 μg/m3. In descending order, the factors affecting the indoor PM2.5 concentration in the apartment studied were range hood use, cooking methods, window status, and air supply system. The PM2.5 peak in the adjacent room occurred 200–800 s later than that in the kitchen. Other conditions being constant in these experiments, the use of range hoods, air supply systems, and windows reduce exposure doses by 90%, 37%, and 51%, respectively. These research results provide insights for reducing human exposure to cooking-generated PM2.5.

Analysis and research on inherent angle ventilation control of residential kitchen range hoods

The emission of oil fume particles during kitchen cooking processes constitutes a significant factor that impacts indoor air quality and human health. Range hoods, as indispensable ventilation devices in kitchens, play a crucial role in reducing indoor particle concentrations. This study employs a combined approach of orthogonal experiments and computational fluid dynamics simulations to investigate the exhaust characteristics of inherent-angle-measurement-based range hoods. It analyzes the diffusion patterns of cooking-generated particulate matter under various cooking scenarios, considering factors such as the opening and closing of windows, cooking source velocities, and different airflow rates of the range hood. Based on different airflow organization patterns, a supplementary ventilation system is designed. The rationality and effectiveness of the supplementary ventilation system are analyzed to establish an effective control scheme for reducing particulate matter in various kitchen environments. The simulated research results indicate that particles disperse along the inclined surface of the side-draft range hood, resulting in higher pollutant concentrations in the breathing zone compared to the cooking zone. Increasing the exhaust airflow rate of the range hood enhances particle capture efficiency by 9.8 %. The induced airflow generated by opening windows improves particle capture efficiency by 12.9 %. However, when the velocity of the window-induced airflow exceeds 1.5 m/s, it hampers the promotion of particle capture efficiency. In the case of windows being unconditionally open, implementing a ceiling-mounted supplementary air supply system effectively improves the kitchen's particle concentration, achieving a maximum particle capture efficiency of 97.66 %. When windows can be opened, setting a baffle on the range hood, the simulation results revealed that with a baffle angle of 120° and a length of 0.3 m, the particle concentration capture efficiency in the breathing zone increased by 34.59 %. This achieved the standard limit requirement of 50 µg/m3, thus meeting the indoor air quality requirements.

Analysis of repairability index to improve disassemblability and serviceability in cooker hoods

Product design plays a key role in supporting the principles of circular economy and sustainability by improving the repair and disassembly capabilities of products. The EN4555X standard series provides a framework and a set of indicators to evaluate these aspects for energy-related products. This paper focuses on applying the RSS (Repair Scoring System) introduced by the EN45554 standard to kitchen ventilation systems (T-shape cooker hood models). The study investigates the reliability of the repairability index by examining the impact of assumptions made during its assessment, particularly focusing on the data and parameters used for calculations. The methodology involves four key steps: identification of index parameters, experimental analysis, sensitivity analysis (SA) through data variation, and result interpretation. The experimental analysis involves computing the RSS index for the chosen range hoods, encompassing a SA developed by varying index’s parameters. Results illustrate that introducing consistent parameter variations across models leads to changes in the Disassemblability Index. However, these alterations remain consistent across all cases, preserving the overall product ranking. Nonetheless, the study also indicates that altering parameter weights may lead to changes in product rankings within the repairability score. This highlights the importance of employing uniform weights within the same product category. In conclusion, this study underscores the importance of employing consistent methodologies and weights to uphold the reliability of repairability indexes when assessing product repairability.

Quality analysis of range hood impeller automated assembly based on generalized grey relational degree

PurposeThis paper establishes a quality model for automation assembly of range hood impeller based on generalized grey relational degree, it improves the debugging efficiency of the newly developed assembly workstation.Design/methodology/approachFirst, spot check the trial production impellers and obtain three indexes that reflect the assembly quality of the impellers. Then, analyze the parameters that affect the assembly quality of the impeller using grey relational analysis (GRA), establish a model for the assembly quality of the range hood impeller based on the generalized grey relational degree and identify the main parameters. After that, analyze the transmission structure of automation assembly workstation, identify the reasons that affect parameters and propose improvement plans. Finally, a trial production is conducted on the automation assembly workstation after adopting the improved plan to verify the quality model of impeller automation assembly.FindingsThe research shows that compared to manual assembly, the automation assembly quality of the impeller using GRA model has been improved, shortening the debugging cycle of the newly developed assembly workstation.Practical implicationsThe newly developed automation equipment will have some problems in the trial production stage, which often rely on the experience of engineers for debugging. In this paper, the automation assembly quality model of range hood impeller based on GRA is established, which can not only ensure the quality of finished impeller but also shorten the debugging cycle of the equipment. In addition, GRA can be widely used in the commissioning of other automation equipment.Originality/valueThis study has developed a set of impeller automation assembly workstation. The debugging method in the trial production stage is beneficial to shorten the trial production time and improve the economic benefits.

Association between household and outdoor air pollution and risk for metabolic syndrome among women in Beijing, China

ABSTRACT This study explored whether household and outdoor air pollution is associatedwith a greater risk for metabolic syndrome (MetS) among women. In all 11,860 women who cooked with clean energy were included in the analysis. Cooking frequency, range hood use during cooking, passive smoking exposure, and solid fuel use for heating were used to represent household air pollution. The 2-year average concentration of PM2.5, and face mask usage were used to reflect outdoor air pollution exposure. An index of air pollution exposure was also constructed. Multivariable logistic regression models were used to estimate the association between air pollution and risk for MetS, and a positive correlation was found. Our results indicated that household cooking used clean energy and exposure to a high level of outdoor PM2.5 without face mask usage may contribute to an increased risk for MetS among women.

Hybrid ventilation in residential and office buildings

This project is focused on hybrid ventilation systems, a combination of natural and mechanical ventilation in residential and office buildings. Especially in dwellings hybrid ventilation systems are quite common. For instance, this can be the frequently occurring combination of exhaust fans in bathroom and toilet and / or a range hood in the kitchen with window ventilation in the other rooms. Currently, these systems are part of the planning reality, however, there are neither planning aids nor focused building standards available. A recently completed research project documents the state of the scientific knowledge, identifies most common planning challenges, and thus provides the basis for future planning aids for hybrid ventilation. This paper sets out to define the term “hybrid ventilation”, presents the most common hybrid ventilation systems in Switzerland and gives planning guidelines for current components of hybrid ventilation systems.

공동주택의 전열교환기와 주방레인지후드의 유동간섭에 관한 연구

공동주택의 전열교환기와 주방레인지후드의 유동간섭에 관한 연구

Emissions of formaldehyde and nitrogen dioxide from liquefied petroleum gas combustion

Liquefied petroleum gas (LPG) is a primary fuel in rural residence. LPG burning can generate detrimental air pollutants, e.g. formaldehyde (HCHO) and nitrogen dioxide (NO2), posing health hazard to human beings and affecting atmospheric environment. However, emission characteristics of HCHO and NO2 from LPG combustion remains unclear. To address this issue, this study investigated emission rate and emission factor of formaldehyde and NO2 by field measurements in nine Chinese kitchens. Results showed that LPG combustion rate in this study varied in 185 mg/min - 4477 mg/min. Given this combustion rate, emission rates of formaldehyde and NO2 ranged from 0.003 mg/min to 0.460 mg/min (median: 0.125 mg/min) and 0.004 mg/min to 0.746 mg/min (median: 0.139 mg/min), respectively. Accordingly, emission factor of formaldehyde and NO2 were in a range of 1.65–1064 mg/kg (median: 151 mg/kg) and 1.84–611 mg/kg (median: 111 mg/kg), respectively. As LPG flow increased, emission factor of formaldehyde and NO2 decreased significantly (p < 0.05). For typical use in residences, annual emissions of formaldehyde and NO2 from household LPG combustion were estimated up to 3200 ± 2775 tons and 2400 ± 1953 tons in China, respectively. Formaldehyde and NO2 dispersed quickly from kitchen to an adjacent living room when kitchen door was open. The range hood exhaust can substantially remove formaldehyde (decrease by 58%) and NO2 (decrease by 57%) when window is open and kitchen door is closed. This study provides baseline information on pollutant emissions from LPG combustion along with CO2, and also reveals that building electrification can have both health and climate yields.