Smoke Flow in Chinese Kangs

Abstract

Chinese kangs are widely used today, in nearly 85% of rural homes by 175 million people in Northern China. While Chinese kangs are a potentially energy sustainable solution for home heating, existing systems are characterized by their poor energy efficiency and significant concerns about the impact of indoor air pollution in homes caused by smoke backflow or smoke leakages. Existing kang designs are based on the intuition and historical accumulation of past craftsmanship experiences. As the first attempt, a macroscopic thermal-fluid approach is used to model the airflow and heat transfer process of an elevated kang with a focus on smoke flow. This model considers nonlinear interaction of thermal buoyancy force, wind force and heat transfer from kang plates and chimney walls. Five parameter groups are identified for characterizing the kang systems to guide the kang smoke flow design. Our work has explained the so-called smoke backflow phenomenon that can lead to serious indoor air quality problems in rural homes and based on the results, we have provided some design recommendations for avoiding smoke backflowand for enhancing energy efficiency by increasing the heat utilization of the kang body.

Keywords

Chinese kang Elevated kang Macroscopic model Smoke backflow

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References

Zhuang Z. , Li YG , Chen B. , Guo JY : Chinese kang as a domestic heating system in rural Northern China - a review : Energy and Buildings 2009;1:111-119.

Li ZX : Study on the status of indoor air pollution from burning in Helingeer . Master thesis, West China School of Public Health, Sichuan University , 2005 (In Chinese).

Bruce N. , Perez-Padilla R. , Albalak R. : Indoor air pollution in developing countries: a major environmental and public health challenge: Bull World Health Organ 2000;9:1078-1092.

Ezzati M. , Kammen DM : Indoor air pollution from biomass combustion and acute respiratory infections in Kenya: an exposure-response study: Lancet 2001;358:619-624.

Smith KR , Mehta S. , Maeusezahl-Feuz M. : Indoor air pollution from household solid fuel use: In Comparative Quantification of Health Risks: Global and Regional Burden of Disease due to Selected Major Risk Factors, Chap. 18, Geneva, World Health Organization, 2004, pp. 1435-1493.

Ezzati M. , Lopez AD , Vander Hoorn S. , Rodgers A. , Murray CJL , Comparative risk assessment collaborative group: Selected major risk factors and global and regional burden of disease: Lancet 2002;360:1347-1360.

Li YG : Analysis of natural smoke flow - a summary of existing analytical solutions. International Energy Agency Annex 35 project Technical Report, Aalborg University, Denmark, 2002.

Li YG , Delsante A. : Natural smoke flow induced by combined wind thermal forces: Building Environ 2001;1:59-71.

Andersen KT : Theory for natural smoke flow by thermal buoyancy in one zone with uniform temperature: Building Environ 2003 ;11:1281-1289.

10.

Li YG , Delsante A. , Chen ZD , Sandberg M. , Andersen A. , Bjerre M. , Heiselberg P. : Some examples of solution multiplicity in natural smoke flow: Building Environ 2001;7:851-858.

11.

Patankar SV : Numerical Heat Transfer and Fluid Flow. Washington DC, USA, Hemisphere Publishing Corporation, 1980 .

12.

Liaoning Province Quality and Technology Supervisory Bureau: Construction Regulations of Efficient Pre-installed Shelf and Kanglinked Stoves, 2004 (In Chinese).

13.

Andersen KT : Airflow rates by combined natural smoke flow with opposing wind-unambiguous solutions for practical use: Building Environ 2007;2:534-542.

14.

Zhuang Z. , Li YG , Duanmu L. , Wang ZS , Chen B. , Qian H. , Sun YF , Zhao Y. , Liu L. : Experimental assessment of thermal performance of an elevated Chinese kang system: In the 1st International Conference on Building Energy and Environment. Dalian, China, 2008.

15.

Idelchik IE , Steinberg MO : Handbook of Hydraulic Resistance. Boca Raton, CRC Press, 1993.

16.

Xi SG , Wu WL , Jiang JY : Boiler and Equipment of Boiler House. Beijing, China Architecture and Building Press, 2002 (In Chinese).