Study On Rural Heating Systems Which Based On Hot-wall Kang

Kang, which is the oldest heating system in rural area, helps farmers keep rooms warmer for thousands of years. It is really an efficient and unattached heating system. With the rapid development of rural society and economy, the thermal comfort needs to be improved in rural houses. Since Kang is always constructed by experience, which is short of theory basis, they show different thermal performances. Most of the traditional Kang's faceplate temperature field is uneven. Besides, the total efficiency of traditional Kang is also very low which causes the heating effects are not satisfactory. Hence, the rural houses' thermal environment is very uncomfortble in rural area, especially for the rooms that without Kang and hot-wall. Territories heating are adapted to enhance the thermal environment which causes more commercial energy are consumed. Therefore, Kang needs to be improved and new heating system needs to be designed to make the thermal environment in rural house be better. There are much more work need to be done to provide guidance for Kang's design and construction.Hot-wall Kang is chosen to be the study background in this paper. Heat transfer and fluid mechanics are used to analyze the research results of hot-wall Kang. Consequent researches have been done as follows.Firstly, the improvement measures are provided according to the deficiencies of hot-wall Kang. Experiments in winter and fall have been done to testify the improvement effects. The results show that the exhaust flue gas temperature of hot-wall has decreased 20～35℃, the flue gas flow inside of Kang is more uniform, the temperature of hot-wall's middle and backend have raised which cause the mean temperature of hot-wall increased about 10-20℃. Through the improvement of hot-wall Kang, the Kang's heating ability is enhanced.Secondly, hot-water system is added to hot-wall Kang. It is a new concept heating system in rural area. Part of the energy produced in the hot-wall system is transmitted using hot water into other rooms without any heating system. A preliminary field measurement has been carried out to study the thermal performance of the Kang, the hot-water heating system as well as the indoor thermal environment. The results demonstrate that the new heating system can provide sufficient heat under the test conditions. The surface temperature of Kang also becomes more even. Different kinds of biomass fuels may be used with the new heating system.Finally, oxygen consumption method and carbon dioxide generation method are introduced in this paper. Also they are used to predict the heat release rate of fuel when they are burned in hot-wall. The results show that the heat release rate of corn stalk is far higher than corn cob when they are burned in the same hot-wall.The heat release rate of corn cob ranges from 0 to 80kW, and the heat release rate of corn stalk ranges from 0 to 120kW. Both heat release rate curves of corn stalk and corn cob obey normal distribution law. Error analysis is done to examine the reliability of the heat release rate curves. These results can be used to provide foundation for combustions model's building.