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13 pages, 1524 KiB

Open AccessArticle

Performance Comparison of High-Temperature Heat Pumps with Different Vapor Refrigerant Injection Techniques

by Yuqiang Yang, Yu Wang, Zhaoyang Xu, Baojiang Xie, Yong Hu, Jiatao Yu, Yehong Chen, Ting Zhang, Zhenneng Lu and Yulie Gong

Processes 2024, 12(3), 566; https://doi.org/10.3390/pr12030566 - 13 Mar 2024

Viewed by 742

Abstract

In order to develop a highly efficient and stable high-temperature heat pump to realize high-efficient electrification in the industrial sector, performance of high-temperature heat pumps with a flash tank vapor injection and sub-cooler vapor injection are compared under different evaporation temperatures, condensation temperatures, [...] Read more.

In order to develop a highly efficient and stable high-temperature heat pump to realize high-efficient electrification in the industrial sector, performance of high-temperature heat pumps with a flash tank vapor injection and sub-cooler vapor injection are compared under different evaporation temperatures, condensation temperatures, compressor suction superheat degrees, subcooling degrees and compressor isentropic efficiencies. The results show that the COP, injection mass flow ratio and VHC of the FTVC are higher than those of the SVIC-0, SVIC-5, SVIC-10 and SVIC-20 under the same working conditions, while the discharge temperature of the FTVC is approximately equal to that of the SVIC-0 and lower than those of the SVIC-5, SVIC-10 and SVIC-20. When the evaporation temperature, the condensation temperature and injection pressure are 55 °C, 125 °C and 921.4 kPa, respectively, the system COP of the FTVC is 4.49, which is approximately 6.7%, 7.3%, 7.8% and 8.9% higher than those of the SVIC-0, SVIC-5, SVIC-10, and SVIC-20, respectively. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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14 pages, 854 KiB

Open AccessArticle

Evaluation and Prediction of the Effect of Fabric Wetting on Coolness

by Zijiang Wu, Yunlong Shi, Xiaoming Qian and Haiyang Lei

Processes 2023, 11(8), 2298; https://doi.org/10.3390/pr11082298 - 31 Jul 2023

Viewed by 663

Abstract

As an important parameter of garment comfort, the thermal sensation of fabrics changes with factors such as sweat-induced humidity, making it a crucial area of research. To explore the coolness sensation of fabrics under different humidities, we tested heat transfer between fabrics and [...] Read more.

As an important parameter of garment comfort, the thermal sensation of fabrics changes with factors such as sweat-induced humidity, making it a crucial area of research. To explore the coolness sensation of fabrics under different humidities, we tested heat transfer between fabrics and skin for 20 different fabrics with varying thermal absorption rates using fuzzy comprehensive evaluation to objectively assess their coolness levels. Subjective evaluation was then obtained by having subjects touch the fabrics and provide feedback, resulting in a subjective evaluation of their coolness levels. We compared the objective and subjective evaluations and found them to be highly consistent (R² = 0.909), indicating accurate objective classification of fabric coolness levels. Currently, random forest regression models are widely used in the textile industry for classification, identification, and performance predictions. These models enable the prediction of fabric coolness levels by simultaneously considering the impact of all fabric parameters. We established a random forest regression model for predicting the coolness of wet fabrics, obtaining a high accuracy between predicted and tested thermal absorption coefficients (R² = 0.872, RMSE = 0.305). Therefore, our random forest regression model can successfully predict the coolness of wet fabrics. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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16 pages, 1734 KiB

Open AccessArticle

Modification and Validation of a Dynamic Thermal Resistance Model for Wet-State Fabrics

by Zijiang Wu, Yunlong Shi, Ruiliang Yang, Xiaoming Qian and Shuting Fang

Processes 2023, 11(6), 1630; https://doi.org/10.3390/pr11061630 - 26 May 2023

Cited by 1 | Viewed by 1184

Abstract

To investigate the dynamic thermal resistance of woven fabrics in different wetting states, ten commonly used clothing fabrics were selected and tested for fabric thermal resistance under different levels of water saturation in accordance with Chinese national standards. Based on Mangat’s eight thermal [...] Read more.

To investigate the dynamic thermal resistance of woven fabrics in different wetting states, ten commonly used clothing fabrics were selected and tested for fabric thermal resistance under different levels of water saturation in accordance with Chinese national standards. Based on Mangat’s eight thermal resistance prediction models, the study improved the models by replacing the original moisture content with water content saturation. The suitability of the eight models in predicting the thermal resistance of woven fabrics in wet states was compared using the sum of squared deviations (SSD), sum of absolute deviations (SAD), and correlation coefficient (R²). The results showed that during the process from initial wetting to complete immersion, the measured thermal resistance values of the ten fabric samples were consistent with the predicted values from Model 5 in the theoretical model of thermal resistance (R² > 0.955). The characteristic of Model 5 is that the air thermal resistance and water thermal resistance are first connected in parallel and then connected in series with the fiber thermal resistance. The corrected predicted values from Model 5 were highly consistent with the experimental measurement values and can be used to approximate the thermal resistance of woven fabrics in wet states. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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Review

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26 pages, 11644 KiB

Open AccessFeature PaperReview

Textiles for Very Cold Environments

by Tomasz Blachowicz, Maciej Malczyk, Ilda Kola, Guido Ehrmann, Eva Schwenzfeier-Hellkamp and Andrea Ehrmann

Processes 2024, 12(5), 927; https://doi.org/10.3390/pr12050927 - 1 May 2024

Viewed by 494

Abstract

Textiles are often used to protect people from cold environments. While most garments are designed for temperatures not far below 0 °C, very cold regions on the earth near the poles or on mountains necessitate special clothing. The same is true for homeless [...] Read more.

Textiles are often used to protect people from cold environments. While most garments are designed for temperatures not far below 0 °C, very cold regions on the earth near the poles or on mountains necessitate special clothing. The same is true for homeless people who have few possibilities to warm up or workers in cooling chambers and other cold environments. Passive insulating clothing, however, can only retain body heat. Active heating, on the other hand, necessitates energy, e.g., by batteries, which are usually relatively heavy and have to be recharged regularly. This review gives an overview of energy-self-sufficient textile solutions for cold environments, including energy harvesting by textile-based or textile-integrated solar cells; piezoelectric sensors in shoes and other possibilities; energy storage in supercapacitors or batteries; and heating by electric energy or phase-change materials. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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13 pages, 2542 KiB

Open AccessReview

Current Research Status and Development Trends of Cooling Suits in High-Temperature Mine Environments: A Review

by Yu Ma, Qing Wan, Zidan Gong, Yiwei Wu and Jie Zhou

Processes 2023, 11(11), 3256; https://doi.org/10.3390/pr11113256 - 20 Nov 2023

Cited by 1 | Viewed by 1094

Abstract

To gain a deeper understanding of the current research status of cooling suits in high-temperature mines, this paper provides separate introductions to vest-type cooling suits and full-body cooling suits. It summarizes the categories of cooling suits based on different cooling media and systematically [...] Read more.

To gain a deeper understanding of the current research status of cooling suits in high-temperature mines, this paper provides separate introductions to vest-type cooling suits and full-body cooling suits. It summarizes the categories of cooling suits based on different cooling media and systematically elucidates the advantages and disadvantages of each type. The paper also analyzes the current application status of cooling suits in mine environments. It suggests that the future research directions for cooling suits in mines include the miniaturization of components, intelligent temperature control, optimization of new phase-change materials, development of cooling fabrics, and research in smart fibers. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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25 pages, 6864 KiB

Open AccessReview

Personal Wearable Thermal and Moisture Management Clothing: A Review on Its Recent Trends and Performance Evaluation Methods

by Junming Zhou, Jinming Zhao, Xiaolei Guo, Yuxing Hu, Xiaofeng Niu and Faming Wang

Processes 2023, 11(11), 3063; https://doi.org/10.3390/pr11113063 - 25 Oct 2023

Viewed by 1527

Abstract

Personal wearable systems designed to manage temperature and moisture are gaining popularity due to their potential to enhance human thermal comfort, safety, and energy efficiency, particularly in light of climate change and energy shortages. This article presents the mechanisms of thermal and moisture [...] Read more.

Personal wearable systems designed to manage temperature and moisture are gaining popularity due to their potential to enhance human thermal comfort, safety, and energy efficiency, particularly in light of climate change and energy shortages. This article presents the mechanisms of thermal and moisture management, recent advances in wearable systems for human thermal and moisture management, and methods for their performance evaluation. It evaluates the pros and cons of various systems. The study finds that most wearable systems for thermal and moisture management are being examined as individual topics. However, human heat and moisture management have noteworthy interactions and impacts on human thermal comfort. There are certain limitations in the methods used for evaluating personal heat and moisture management in wearable systems. This review suggests future research directions for wearable systems to advance this field and overcome these limitations. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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15 pages, 3522 KiB

Open AccessFeature PaperReview

Quantitative Comparison of Personal Cooling Garments in Performance and Design: A Review

by Yiying Zhou, Lun Lou and Jintu Fan

Processes 2023, 11(10), 2976; https://doi.org/10.3390/pr11102976 - 14 Oct 2023

Cited by 1 | Viewed by 1838

Abstract

Personal cooling garments (PCGs) have gained increasing attention as a promising solution to alleviate heat stress and enhance thermal comfort in hot and humid conditions. However, limited attention has been paid to the influence of clothing design on cooling performance. This review highlights [...] Read more.

Personal cooling garments (PCGs) have gained increasing attention as a promising solution to alleviate heat stress and enhance thermal comfort in hot and humid conditions. However, limited attention has been paid to the influence of clothing design on cooling performance. This review highlights the influence of design factors and provides a quantitative comparison in cooling performance for different types of PCGs, including air cooling garments, evaporative cooling garments, phase-change cooling garments, and liquid cooling garments. A detailed discussion about the relationship between design factors and the cooling performance of each cooling technique is provided based on the available literature. Furthermore, potential improvements and challenges in PCG design are explored. This review aims to offer a comprehensive insight into the attributes of various PCGs and promote interdisciplinary collaboration for improving PCGs in both cooling efficiency and garment comfort, which is valuable for further research and innovation. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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14 pages, 7994 KiB

Open AccessReview

Systematic Evaluation of Research Progress in the Textile Field over the Past 10 Years: Bibliometric Study on Smart Textiles and Clothing

by Ting Wang, Changqing Liu, Jun Zhang and Aosi Wang

Processes 2023, 11(9), 2797; https://doi.org/10.3390/pr11092797 - 20 Sep 2023

Viewed by 1013

Abstract

Intelligent textile clothing is one of the most popular topics in the field. In recent decades, rapid advances have been made in the area of intelligent textile clothing research, and the intellectual structure pertaining to this domain has significantly evolved. We used CiteSpace [...] Read more.

Intelligent textile clothing is one of the most popular topics in the field. In recent decades, rapid advances have been made in the area of intelligent textile clothing research, and the intellectual structure pertaining to this domain has significantly evolved. We used CiteSpace 6.2.R4, VOSviewer 1.6.19, to evaluate and visualize the results, analyzing articles, countries, regions, institutions, authors, journals, citations, and keywords. Both a macroscopic sketch and a microscopic characterization of the entire knowledge domain were realized. The aim of this paper is to utilize bibliometric and knowledge mapping theories to identify relevant research papers on the subject of smart textiles and clothing that have been published by the China Knowledge Network Web of Science (WOS) within the last decade. It is concluded that the main topics of smart textile and garment research can be divided into nine categories: wearable electronics, smart textiles, flexible antennas, energy storage, textile actuators, mechanical properties, asymmetric supercapacitors, carbon nanotubes, and fiber extrusion. In addition to the latter analysis, emerging trends and future research foci were predicted. This review will help scientists discern the dynamic evolution of intelligent textile clothing research as well as highlight areas for future research. Full article

(This article belongs to the Special Issue Smart Wearable Technology: Thermal Management and Energy Applications)

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