A field study of CO2 and particulate matter characteristics during the transition season in the subway system in Tianjin, China

Ren, Jing; He, Junjie; Kong, Xiangming; Xu, Wei; Kang, Yiting; Yu, Zhen; Li, Hongwan

doi:10.1016/j.enbuild.2021.111620

Cited by 31 publications

(14 citation statements)

References 45 publications

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“…The evaluations were calculated for the energy consumption of ventilation and filtration systems [ 11 , 50 , 51 , 52 ] and the operating cost-effectiveness of the ventilation and filtration systems. The optimal return air heights for different types of supply air were subsequently identified, and, thus, the results can not only meet the air quality requirements, but also save energy.…”

Section: Resultsmentioning

confidence: 99%

Effects of Return Air Inlets’ Location on the Control of Fine Particle Transportation in a Simulated Hospital Ward

Ren

Duan

Guo

et al. 2022

IJERPH

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The COVID-19 pandemic has made significant impacts on public health, including human exposure to airborne pathogens. In healthcare facilities, the locations of return air vents in ventilation systems may have important effects on lowering airborne SARS-CoV-2 transmission. This study conducted experiments to examine the influence of different return air vents’ heights (0.7 m, 1.2 m, and 1.6 m) on the particle removal effects in a simulated patient ward. Three different ventilation systems were examined: top celling air supply-side wall return (TAS), underfloor air supply-side wall return (UFAS) and side wall air supply-side wall return (SAS). CFD simulation was applied to further study the effects of return air inlets’ heights (0.3 m, 0.7 m, 1.2 m, 1.6 m, and 2.0 m) and air exchange rates. The technique for order of preference by similarity to ideal solution (TOPSIS) analysis was used to calculate the comprehensive scores of 60 scenarios using a multi-criterion method to obtain the optimal return air inlets’ heights. Results showed that for each additional 0.5 m distance in most working conditions, the inhalation fraction index of medical staff could be reduced by about 5–20%. However, under certain working conditions, even though the distances between the patients and medical personnel were different, the optimal heights of return air vents were constant. For TAS and UFAS, the optimal return air inlets’ height was 1.2 m, while for SAS, the best working condition was 1.6 m air supply and 0.7 m air return. At the optimum return air heights, the particle decay rate per hour of SAS was 75% higher than that of TAS, and the rate of particle decay per hour of SAS was 21% higher than that of UFAS. The location of return air inlets could further affect the operating cost-effectiveness of ventilation systems: the highest operating cost-effectiveness was 8 times higher than the lowest one.

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Section: Resultsmentioning

confidence: 99%

Effects of Return Air Inlets’ Location on the Control of Fine Particle Transportation in a Simulated Hospital Ward

Ren

Duan

Guo

et al. 2022

IJERPH

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“…Ren measured the CO2 concentration during the transition season in the subway in Tianjin and found that when the HVAC system was off, the values in the morning and evening peak were far higher than the limit in the standards. And when the HVAC system is on, the concentration decreased by 21%-27% [1]. Differences in concentration have been found in above-ground and underground lines, urban and suburban areas.…”

Section: Introductionmentioning

confidence: 96%

Analysis of dynamic characteristics of CO₂ concentration in subway cars

Yang

Wang

2022

E3S Web Conf.

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The air environment in the subway car has a great impact on the comfort and health of passengers. In order to know the real air quality in the car when the train is running, this paper takes CO2 as an indicator and conducts a field test on Line 11 of Shanghai Metro to study and analyse the dynamic CO2 concentration and the fresh air rate in the subway car. The results show that the CO2 concentration increases from the head car to the tail car, and the fresh air volume decreases from the head car to the tail car is the reason for the large difference of CO2 concentration in different cars. The CO2 concentration in the car is greatly affected by the passenger load, and the maximum value of CO2 concentration in the morning peak can reach 2.3 times that of the normal hours. The background CO2 concentration has a certain influence on the CO2 concentration in the car, and the CO2 concentration in the underground line is higher than that in the elevated line in the same carriage. The CO2 concentration in subway cars of the underground line in the morning peak is significantly higher than 1500 ppm, which indicates that the dilution effects of the ventilation can’t meet the fresh air requirements in the morning peak. The research in this paper can provide a reference for the design of the ventilation system of subway trains and the environmental control in the car.

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“…One important measure to achieve emissions reduction is to focus on energy efficiency and adjust the energy service demand through behavioral change [ 2 ]. The building sector is responsible for 33% of global CO2 emissions, and HVAC systems are the crucial energy consumer in buildings with the largest share [ 3 ]. Nearly zero energy buildings (NZEB) offer a significant opportunity for both energy use and emissions reduction [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Heating Control Strategy Based on Dynamic Programming for Building Energy Saving and Emission Reduction

Qin

et al. 2022

IJERPH

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Finding the optimal balance between end-user’s comfort, lifestyle preferences and the cost of the heating, ventilation and air conditioning (HVAC) system, which requires intelligent decision making and control. This paper proposes a heating control method for HVAC based on dynamic programming. The method first selects the most suitable modeling approach for the controlled building among three machine learning modeling techniques by means of statistical performance metrics, after which the control of the HVAC system is described as a constrained optimization problem, and the action of the controller is given by solving the optimization problem through dynamic programming. In this paper, the variable ‘ thermal energy storage in building ‘ is introduced to solve the problem that dynamic programming is difficult to obtain the historical state of the building due to the requirement of no aftereffect, while the room temperature and the remaining start hours of the Primary Air Unit are selected to describe the system state through theoretical analysis and trial and error. The results of the TRNSYS/Python co-simulation show that the proposed method can maintain better indoor thermal environment with less energy consumption compared to carefully reviewed expert rules. Compared with expert rule set ‘baseline-20 °C’, which keeps the room temperature at the minimum comfort level, the proposed control algorithm can save energy and reduce emissions by 35.1% with acceptable comfort violation.

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A field study of CO2 and particulate matter characteristics during the transition season in the subway system in Tianjin, China

Cited by 31 publications

References 45 publications

Effects of Return Air Inlets’ Location on the Control of Fine Particle Transportation in a Simulated Hospital Ward

Effects of Return Air Inlets’ Location on the Control of Fine Particle Transportation in a Simulated Hospital Ward

Analysis of dynamic characteristics of CO₂ concentration in subway cars

Heating Control Strategy Based on Dynamic Programming for Building Energy Saving and Emission Reduction

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A field study of CO2 and particulate matter characteristics during the transition season in the subway system in Tianjin, China

Cited by 31 publications

References 45 publications

Effects of Return Air Inlets’ Location on the Control of Fine Particle Transportation in a Simulated Hospital Ward

Effects of Return Air Inlets’ Location on the Control of Fine Particle Transportation in a Simulated Hospital Ward

Analysis of dynamic characteristics of CO2 concentration in subway cars

Heating Control Strategy Based on Dynamic Programming for Building Energy Saving and Emission Reduction

Contact Info

Product

Resources

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Analysis of dynamic characteristics of CO₂ concentration in subway cars