The heat transfer coefficient of the external surface of building envelope （ht） is a fundamental parameter in thermal calculations. However, the unique climatic conditions in high-altitude regions result in significant deviations in ht compared to standard values used for low-altitude areas. To determine the measurement methods and calculation values of ht in high-altitude areas, this study employed the naphthalene sublimation method and simplified radiation theory to measure the convective heat transfer coefficient （hc） and radiative heat transfer coefficient （hr） of the external surface of an exhibition hall in Lhasa. Based on typical annual meteorological data, the hourly values of ht for the entire year are calculated. The results demonstrate that the naphthalene sublimation method has a measurement error of 4.3%, confirming its applicability in Lhasa. The measured hc ranges from 2.22 to 20.33 W/（m2·K）, with horizontal surfaces exhibiting values 0.86 W/（m2·K） higher than vertical surfaces, showing a linear correlation with wind speed. The hrranges from 4.50 to 5.61 W/（m2·K）, with small variation, and an average value of 4.88 W/（m2·K） is recommended. Considering the actual wind speed and radiation conditions in Lhasa, the calculated annual ht values most frequently fall within the range of 10.00-15.00 W/（m2·K）, with winter and summer averages of 15.63 and 16.69 W/（m2·K）, respectively, both of which are lower than the standard recommended value of 18.00 W/（m2·K）.
Key words
heat transfer coefficient /
convection /
radiation /
high altitude /
naphthalene sublimatio
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
References
[1] 翁楚彬, 周雄冬, 徐梦珍. 西藏可再生能源开发适宜度评价[J]. 太阳能学报, 2023, 44(1): 475-484.
WENG C B, ZHOU X D, XU M Z.Research on suitability of renewable energy exploitation in Tibet[J]. Acta energiae solaris sinica, 2023, 44(1): 475-484.
[2] 许馨尹, 冯珩力, 杨柳, 等. 中国太阳能富集区居住建筑光储系统设计方法研究[J]. 太阳能学报, 2024, 45(7): 101-110.
XU X Y, FENG H L, YANG L, et al.Optimized design method of PV-battery energy system for residential buildings in China solar-rich area[J]. Acta energiae solaris sinica, 2024, 45(7): 101-110.
[3] GB 50176—2016, 民用建筑热工设计规范[S].
GB 50176—2016, Code for thermal design of civil building[S].
[4] HAGISHIMA A, TANIMOTO J.Field measurements for estimating the convective heat transfer coefficient at building surfaces[J]. Building and Environment, 2003, 38(7): 873-881.
[5] LIU Y, HARRIS D J.Full-scale measurements of convective coefficient on external surface of a low-rise building in sheltered conditions[J]. Building and environment, 2007, 42(7): 2718-2736.
[6] 朱新荣, 杨轩, 杨雯, 等. 采暖建筑外表面热流及换热系数现场测试研究[J]. 太阳能学报, 2021, 42(8): 258-264.
ZHU X R, YANG X, YANG W, et al.Field testing of heat flux and heat exchange coefficients on heated building exterior surface[J]. Acta energiae solaris sinica, 2021, 42(8): 258-264.
[7] YANG W, ZHU X R, LIU J P.Annual experimental research on convective heat transfer coefficient of exterior surface of building external wall[J]. Energy and buildings, 2017, 155: 207-214.
[8] 杨轩. 建筑外表面热流及换热系数的规律特征与空间分布[D]. 西安: 西安建筑科技大学, 2020.
YANG X.Regular characteristics and spatial distribution of heat flow and heat transfer coefficient on the outer surface of buildings[D]. Xi’an: Xi’an University of Architecture and Technology, 2020.
[9] KEUMNAM C, IRVINE T F, KARNI J.Measurement of the diffusion coefficient of naphthalene into air[J]. International journal of heat and mass transfer, 1992, 35(4): 957-966.
[10] 刘京, 付志鹏, 邵建涛, 等. 应用萘升华法实测建筑外表面对流换热[J]. 天津大学学报, 2009, 42(8): 683-688.
LIU J, FU Z P, SHAO J T, et al.Field measurement of convective heat transfer on external surface of building using naphthalene sublimation method[J]. Journal of Tianjin University, 2009, 42(8): 683-688.
[11] 付志鹏. 采用萘升华技术对建筑外表面对流换热的研究[D]. 哈尔滨: 哈尔滨工业大学, 2007.
FU Z P.The research on building outside surface convective heat transfer measurement using naphthalene sublimation[D]. Harbin: Harbin Institute of Technology, 2007.
[12] CUI Y P, XIE J C, XUE P, et al.Analysis on applicability and feasibility of popularizing the naphthalene sublimation technique in island-reef areas[J]. Ashrae transactions, 2019, 125: 503-512.
[13] 崔亚平, 谢静超, 刘加平, 等. 极端热湿气候区建筑外壁面总换热系数研究[J]. 太阳能学报, 2019, 40(2): 586-592.
CUI Y P, XIE J C, LIU J P, et al.Research on total heat transfer coefficient at exterior building surface in extreme hot-humid climate zone[J]. Acta energiae solaris sinica, 2019, 40(2): 586-592.
PDF(1995 KB)
