Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban Areas
In recent years, the surge in air-conditioning ownership and usage has led to significant heat rejection, impacting the surrounding atmosphere. Despite this, studies examining the spatiotemporal effects of air-conditioning heat rejection at a block scale remain limited. Additionally, comparative stu...
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MDPI AG
2025-01-01
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| author | Kang Mu Qiong Suo Fangliang Ding Changwei Jiang Xiaofeng Zhang Jing Ye |
| author_facet | Kang Mu Qiong Suo Fangliang Ding Changwei Jiang Xiaofeng Zhang Jing Ye |
| author_sort | Kang Mu |
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| description | In recent years, the surge in air-conditioning ownership and usage has led to significant heat rejection, impacting the surrounding atmosphere. Despite this, studies examining the spatiotemporal effects of air-conditioning heat rejection at a block scale remain limited. Additionally, comparative studies on the role of building areas with air-conditioning systems versus natural underlying surfaces in the urban thermal environment are relatively scarce. This study employs field measurements and ArcGIS technology to investigate the local thermal and humidity environments, as well as the spatiotemporal distribution of heat rejection from air-conditioning systems in Wuyi Square, Changsha. Results show that cooling tower exhausts in commercial buildings maintain relative humidity levels of 95.2% to 99.8% during the day, enhancing surrounding humidity. At night, the humidity aligns with atmospheric levels (from 50.3% to 62.5%). The cooling tower exhaust temperature is approximately 2.2 °C lower during the day and 2.4 °C higher at night compared to the surrounding temperatures. In contrast, exhausts from split-type air-conditioning units in residential buildings have an average relative humidity about 14.2% lower than the atmosphere humidity, with temperature averages being 5.2 °C higher during the day and 6.5 °C higher at night, raising surrounding temperatures. The study also finds that natural surface areas are up to 3.1 °C cooler and 9.6% more humid compared to built environment surfaces. Furthermore, residential areas have air temperatures about 0.3 °C higher than commercial zones, with a humidity distribution approximately 0.5% lower. These findings offer a theoretical foundation for enhancing urban thermal environments and informing urban planning and design. |
| format | Article |
| id | doaj-art-ea5e4a2fa8ca41179e50ae53ce1c3f9d |
| institution | Kabale University |
| issn | 2073-4433 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
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| series | Atmosphere |
| spelling | doaj-art-ea5e4a2fa8ca41179e50ae53ce1c3f9d2025-01-24T13:22:01ZengMDPI AGAtmosphere2073-44332025-01-0116110010.3390/atmos16010100Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban AreasKang Mu0Qiong Suo1Fangliang Ding2Changwei Jiang3Xiaofeng Zhang4Jing Ye5College of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaCollege of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaCollege of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaCollege of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaCollege of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaCollege of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, ChinaIn recent years, the surge in air-conditioning ownership and usage has led to significant heat rejection, impacting the surrounding atmosphere. Despite this, studies examining the spatiotemporal effects of air-conditioning heat rejection at a block scale remain limited. Additionally, comparative studies on the role of building areas with air-conditioning systems versus natural underlying surfaces in the urban thermal environment are relatively scarce. This study employs field measurements and ArcGIS technology to investigate the local thermal and humidity environments, as well as the spatiotemporal distribution of heat rejection from air-conditioning systems in Wuyi Square, Changsha. Results show that cooling tower exhausts in commercial buildings maintain relative humidity levels of 95.2% to 99.8% during the day, enhancing surrounding humidity. At night, the humidity aligns with atmospheric levels (from 50.3% to 62.5%). The cooling tower exhaust temperature is approximately 2.2 °C lower during the day and 2.4 °C higher at night compared to the surrounding temperatures. In contrast, exhausts from split-type air-conditioning units in residential buildings have an average relative humidity about 14.2% lower than the atmosphere humidity, with temperature averages being 5.2 °C higher during the day and 6.5 °C higher at night, raising surrounding temperatures. The study also finds that natural surface areas are up to 3.1 °C cooler and 9.6% more humid compared to built environment surfaces. Furthermore, residential areas have air temperatures about 0.3 °C higher than commercial zones, with a humidity distribution approximately 0.5% lower. These findings offer a theoretical foundation for enhancing urban thermal environments and informing urban planning and design.https://www.mdpi.com/2073-4433/16/1/100air-conditioning heat rejectionthermal environmentmobile measurementunderlying surface |
| spellingShingle | Kang Mu Qiong Suo Fangliang Ding Changwei Jiang Xiaofeng Zhang Jing Ye Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban Areas Atmosphere air-conditioning heat rejection thermal environment mobile measurement underlying surface |
| title | Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban Areas |
| title_full | Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban Areas |
| title_fullStr | Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban Areas |
| title_full_unstemmed | Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban Areas |
| title_short | Field Measurements of Building Air-Conditioning Heat Rejection and the Thermal Environment in Urban Areas |
| title_sort | field measurements of building air conditioning heat rejection and the thermal environment in urban areas |
| topic | air-conditioning heat rejection thermal environment mobile measurement underlying surface |
| url | https://www.mdpi.com/2073-4433/16/1/100 |
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