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20 pages, 5882 KiB

Open AccessArticle

Local Thermal Comfort and Physiological Responses in Uniform Environments

by Xianzhun Zhong, Hang Yu, Yin Tang, Huice Mao and Kege Zhang

Buildings 2024, 14(1), 59; https://doi.org/10.3390/buildings14010059 - 24 Dec 2023

Viewed by 840

Abstract

The thermal perception of different body parts can vary greatly throughout the human body and have different influences on overall thermal sensation and comfort. Various personal comfort systems (PCS) have been developed to stimulate local body parts for the purpose of enhancing human [...] Read more.

The thermal perception of different body parts can vary greatly throughout the human body and have different influences on overall thermal sensation and comfort. Various personal comfort systems (PCS) have been developed to stimulate local body parts for the purpose of enhancing human thermal comfort, yet the most effective body parts for intervention remain undetermined. Therefore, a series of climate chamber experiments under five uniform environments with three sets of suits were conducted in this study. The results showed that the head, chest, belly, and hands tended to feel no cooler than overall in cooler environments, but arms and legs felt generally no warmer than overall in warmer environments. The head, trunk and upper arms were more likely to be the comfort-dominant body parts. Additionally, the upper arms and upper back expected temperature regulation measures the most under non-neutral environments, thus they seem to be the two most needed and effective targeted body parts that a PCS could be applied to. The skin temperature and thermal sensation of limbs were more sensitive to indoor air temperatures than those of the torso. However, variations in the skin temperature of the head, chest, upper back, and calves had the strongest correlation with overall sensation vote changes. The above results and conclusions can not only serve as the basis for the future studies of local thermal comfort, but also provide theoretical guidance for the design of future PCS products. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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12 pages, 6975 KiB

Open AccessArticle

Justification of an Energy-Efficient Air Purification System in Subways Based on Air Dust Content Studies

by Tuleukhan Irgibayev, Ivan Lugin and Lavrentij Kiyanitsa

Buildings 2023, 13(11), 2771; https://doi.org/10.3390/buildings13112771 - 3 Nov 2023

Viewed by 626

Abstract

It is not uncommon that subways count as densely populated areas, so air quality standards, including fine dust concentration, have been established for them. As passengers and subway staff are exposed to potentially harmful airborne particles, addressing this issue is vital to ensuring [...] Read more.

It is not uncommon that subways count as densely populated areas, so air quality standards, including fine dust concentration, have been established for them. As passengers and subway staff are exposed to potentially harmful airborne particles, addressing this issue is vital to ensuring a safe and healthy environment on the subway. To reduce the dust concentration in subway systems, the authors propose installing filters to capture dust in ventilation failures between subway tunnels near metro stations. A novel aspect of the proposed method is the fact that airflow will be moved through filters by using the piston action of trains passing through the tunnels. The result of this research provides empirical evidence regarding dust content and mass concentrations of PM2.5 and PM10 in subway environments. While some existing literature discusses air quality in subways, the inclusion of specific measurements and data from the experiment strengthens the understanding of the severity of dust-related air quality issues in such environments. The data for this study were collected in the Almaty subway (Republic of Kazakhstan) at four stations: Raiymbek Batyr, Almaty, Baikonur and Alatau. Measuring points were located on passenger platforms, in the halls and at the entrances to the station. The lab scale tests determined the percentage of particles by their diameters relative to the total volume of dust, the percentage of dust particles smaller than a certain diameter, the percentage of various metal oxides and the average dust density. A preliminary energy assessment has been done on the proposed method of air purification from dust. With a frequency of 24 pairs of trains per hour, the energy savings per ventilation failure will be 240.170 kWh. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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22 pages, 10927 KiB

Open AccessArticle

Simulation Study on Natural Ventilation Performance in a Low-Carbon Large-Space Public Building in Hot-Summer and Cold-Winter Region of China

by Zhaohui Liu, Xi Pan, Wenshan He and Yilin Li

Buildings 2023, 13(9), 2263; https://doi.org/10.3390/buildings13092263 - 6 Sep 2023

Viewed by 990

Abstract

Recently, climate governance has entered a new phase of accelerating decarbonization. In order to achieve low-carbon buildings, natural ventilation has been widely used as it requires no fan power. However, there are great challenges for achieving effective natural ventilation in large-space public buildings [...] Read more.

Recently, climate governance has entered a new phase of accelerating decarbonization. In order to achieve low-carbon buildings, natural ventilation has been widely used as it requires no fan power. However, there are great challenges for achieving effective natural ventilation in large-space public buildings especially in areas characterized by hot-summer and cold-winter climatic regions, due to empirically unsuitable ambient temperatures and theoretically complex joint effect of wind pressure and thermal buoyancy. Therefore, this numerical study was conducted on the performance of a natural ventilation strategy in a large-space public building in a hot-summer and cold-winter region by using computational fluid dynamics (CFD) methods. Simulations were performed by applying FLUENT software for obtaining airflow distributions within and around a typical low-carbon public building. The temperature distribution in the atrium of the building was simulated particularly for analyzing the natural ventilation performance in a large-space area. Results demonstrated that thermal pressure was dominant for the large-space building in the case study. The average indoor airflow velocities on different floors ranged from 0.43 m/s to 0.47 m/s on the windward side which met indoor ventilation requirements. Most areas of wind velocities could meet ventilation requirements. The natural ventilation performance could be improved by increasing the relative height difference between the air inlets and air outlets. These findings could help provide references and solutions for realizing natural ventilation in low-carbon large-space public buildings in hot-summer and cold-winter regions. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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19 pages, 2229 KiB

Open AccessArticle

A Novel Response Factor-Based Method for In Situ Measurement of Wall Thermal Resistance

by Chuang Wang, Xiao Fu, Xiaoran Tao, Xiaoyan Li and Jingjing An

Buildings 2023, 13(8), 1986; https://doi.org/10.3390/buildings13081986 - 3 Aug 2023

Cited by 2 | Viewed by 725

Abstract

The heat flow meter method (HFM) is one of the most-used methods for the in situ measurement of wall thermal resistance. However, the standard HFM method has some issues: it is challenging to balance simplicity and accuracy in data analysis and the measurement [...] Read more.

The heat flow meter method (HFM) is one of the most-used methods for the in situ measurement of wall thermal resistance. However, the standard HFM method has some issues: it is challenging to balance simplicity and accuracy in data analysis and the measurement period needs to be shorter. In this paper, a new dynamic data analysis method for the in situ measurement of wall thermal resistance is introduced, which is based on a truncated form of the infinite response factors for a wall heat conduction process and has a theoretically deducted convergence criteria for the automatic termination of an in situ measurement. The efficacy of the proposed method is validated by a theoretical analysis and by experiments from one simulation dataset and one measurement dataset. Preliminary experimental results show that the proposed method can reduce the measurement time by about one-third on average while maintaining the same accuracy as the standard average method. Due to the advantages of a clear physical meaning, a simple principle, and a short measurement period, the proposed method contributes to the quick and accurate estimation of the wall thermal resistance in buildings. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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17 pages, 4098 KiB

Open AccessArticle

Study on Temperature Distribution along the Ultra-Long Underwater Tunnel: Based on the Long-Term Measured Results of the Shanghai Yangtze River Tunnel

by Jun Gao, Weichen Guo, Mingyao Ma, Yumei Hou, Ruiyan Zhang, Lingjie Zeng, Chengquan Zhang, Yukun Xu, Xiaobin Wei and Changsheng Cao

Buildings 2023, 13(7), 1804; https://doi.org/10.3390/buildings13071804 - 15 Jul 2023

Viewed by 903

Abstract

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 significantly raises the temperature inside, presenting challenges in terms of occupant comfort, tunnel safety, and [...] Read more.

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 significantly raises the temperature inside, presenting challenges in terms of occupant comfort, tunnel safety, and infrastructure integrity. Therefore, ensuring proper temperature control is essential for their efficient operation. This study aims to investigate the phenomenon of temperature rise in ultra-long tunnels during normal operations, as limited research has been conducted in this area. The Shanghai Yangtze River Tunnel serves as a case study, utilizing temperature and air velocity data collected throughout the year (2021) from the management company. The analysis reveals that the temperature distribution near the tunnel exit is influenced by outdoor temperature fluctuations and traffic volume. The highest temperatures occur on 25 August (39.74 °C) during peak traffic hours. On-site measurements of tunnel temperature, humidity, and air velocity during winter and summer seasons yield the following results. During winter, the air temperature and wall temperature inside the tunnel experience significant increases along its length. The air temperature rises by approximately 11 °C from the entrance to the exit, while the wall temperature increases by about 15 °C. In contrast, during summer, the air temperature only rises by 2.7 °C, and the wall temperature increases by around 3 °C. Consequently, the humidity decreases along the tunnel, and this decrease is correlated with the magnitude of temperature increase. Furthermore, measurements of air velocity indicate that natural and traffic-induced winds contribute to the overall airflow inside the tunnel. A temperature data logger installed in the tunnel recorded temperature changes during the period of pandemic lockdown and subsequent recovery, spanning the spring and summer seasons. During the lockdown period, there was a relatively small increase in temperature along the tunnel, suggesting that vehicle heat dissipation is the primary factor contributing to temperature rise inside. Additionally, a method is proposed to predict the cross-sectional temperature of the tunnel using measured air velocities. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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30 pages, 10047 KiB

Open AccessArticle

Optimization of Supply Air Parameters Control Based on Gappy POD Method for Creating Non-Uniform Temperature Fields

by Xin Wang, Yuhong Liu, Zhiyin Cao, Dekang Li, Jinchi Zhao and Wenbing Weng

Buildings 2023, 13(7), 1690; https://doi.org/10.3390/buildings13071690 - 30 Jun 2023

Viewed by 731

Abstract

This paper explores the implementation and application of non-uniform ambient fields from two perspectives: constant heat source and abrupt heat source variation. On the one hand, the proper orthogonal decomposition (POD) method is used to find the optimum air supply parameters for different [...] Read more.

This paper explores the implementation and application of non-uniform ambient fields from two perspectives: constant heat source and abrupt heat source variation. On the one hand, the proper orthogonal decomposition (POD) method is used to find the optimum air supply parameters for different target temperatures at multiple demand points. The one-parameter, two-parameter and three-parameter cases were considered, respectively, and the parameters obtained from the search for optimisation were verified, yielding mean deviations of 0.405 K, 0.368 K and 0.380 K and mean errors of 1.48%, 1.61% and 1.68%, respectively. The accuracy of the reconstructed results of the POD method and the reliability of the POD method for finding the best results are verified step by step with the help of the experimental platform. The validation results show that the average error between the reconstructed data and the experimental data for the POD method does not exceed 5%; the average errors between the measured and set demand temperatures at the target point are 1.2% and 0.8%. On the other hand, the gappy POD method is used to accurately fill in the elements of the system with arbitrary missing data and to reconstruct the flow field in the presence of missing (gappy) data with a limited number of sensors combined with POD. The errors of the gappy POD method reconstruction are 0.54% and 1.75%. POD and gappy POD methods can better create non-uniform temperature fields in practical scenarios according to actual needs. The results of the study can provide a methodological reference for real-time reconstruction and real-time control of the indoor flow field environment. It also serves as a help and suggestion for the actual project in terms of end-regulation system and reverse design method. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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15 pages, 9341 KiB

Open AccessArticle

Experimental Study on the Agglomeration of Oily Fine Particles by Sound Wave

by Xin Wang, Dekang Li, Qi Zhang, Tian Li, Zhiyin Cao and Fei Wang

Buildings 2023, 13(7), 1660; https://doi.org/10.3390/buildings13071660 - 29 Jun 2023

Cited by 1 | Viewed by 919

Abstract

Oily fine particles are an important air pollutant in industrial environments. Workers exposed to oil mist for a long time face great health risks. Particle growth pretreatment is a technical principle to increase particle size and improve purification efficiency. Acoustic waves are commonly [...] Read more.

Oily fine particles are an important air pollutant in industrial environments. Workers exposed to oil mist for a long time face great health risks. Particle growth pretreatment is a technical principle to increase particle size and improve purification efficiency. Acoustic waves are commonly used to acheive particle growth, and a large number of acoustic wave agglomeration experiments have been carried out on non-oil fog. However, studies on oily particles are few. On the basis of previous studies on acoustic agglomeration of non-oily particles, this experiment designed a set of experimental equipment to compare the agglomeration effect of oily and non-oily particles. It was found that the agglomeration effect ratio of oily and non-oily particles to φ1oiliness/φ1non-oily particles was greater than 1. Therefore, the agglomeration effect of oily particles under stationary acoustic waves was more obvious. Results clearly show that oily particles have a higher agglomeration ability. In this study, a traditional ventilation and purification technology was expanded to include sound agglomeration technology into the pretreatment stage of purification and dust removal, thereby demonstrating feasibility of improved purification efficiency of an oily fine particle purification system, and laying a foundation for engineering applications. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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Review

Jump to: Research

11 pages, 2127 KiB

Open AccessReview

Research Progress on the Impact of Acoustic Waves on the Agglomeration of Oily Fine Particles in Industrial Oil Mist Environment

by Dekang Li, Xin Wang, Tian Li, Luying Yang, Yuhong Liu, Fei Wang, Yuwei Xu and Yang Yang

Buildings 2023, 13(8), 1937; https://doi.org/10.3390/buildings13081937 - 29 Jul 2023

Viewed by 888

Abstract

Currently, undetectable damage to workers and factory products is caused by the large number of oily fine particles present in the industrial environment. Previous studies have shown that different intensities of sound waves can promote the coalescence of fine particles, and the combination [...] Read more.

Currently, undetectable damage to workers and factory products is caused by the large number of oily fine particles present in the industrial environment. Previous studies have shown that different intensities of sound waves can promote the coalescence of fine particles, and the combination of water vapor condensation can further enhance the effect of acoustic coalescence. However, the research on acoustic coalescence is not extensive enough at present, especially research on the mechanism of the coalescence and growth of oily fine particles under acoustic and water vapor complex fields, which is even less studied. This paper focused on summarizing domestic and foreign research results on the interaction mechanism of acoustic convergence on particles and the agglomeration and growth of particles under the action of acoustic convergence and combined water vapor condensation, so as to explore the technical path of using acoustic convergence and combined water vapor condensation to regulate the size of oily fine particles and improve the purification efficiency in industrial situations. This research has significant scientific significance and application value for industrial environmental control, pollutant emission control, and healthy environment construction. Full article

(This article belongs to the Special Issue Advances in Built Environment Engineering: Ventilation, Air Conditioning, and Heating Technology)

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