Experimental And Numerical Study On Solar Chinese Kang System Combinedwith Novel Collector-Trombe Wall

Energy consumed in buildings accounts for approximately one third of the whole national energy consumption; and about40%of them are in lighting, ventilating, space heating/cooling, and water heating. Therefore, how to reduce energy consumption of space heating, cooling and hot water and how to transform energy supply methods are of great significance for reducing the energy consumption of our country. Solar energy, due to its advantages of renewable and environmentally friendly, is an important alternatives to fossil fuels. The applications of solar energy technology in buildings are important ways to reduce the conventional energy consumption and use renewable energy on a large-scale.In the rural areas of northern China, Chinese Kangs are widely used in nearly85%of rural homes or175million people for home space heating. Traditional fire Kangs usually keep the residual heat from stove combustion by burning biomass fuels such as straw, stalks and wood during the firing time, and then gradually release heat to heat up a bedroom through thermal storage of Kang body after firings. Because the large number of Chinese Kangs in rural buildings burning biomass fuels, a lot of energy is consumed and there is always serious air pollution during space heating season every year. So, the innovations of the traditional Kangs are crucial for improving of heating technologies for rural residences in northern China. Based on characteristics of solar energy resource-rich and traditional fire Kangs in the rural areas of northern china, solar Chinese Kang system combined with novel shutter-trombe wall is proposed. It makes full use of solar Kang’s heat storage to ensure the thermal comfort of sleep environment at night, while taking advantage of shutter wall to reduce heating load in a bedroom during the day. In this thesis, the following work was accomplished by both experimental studies and theoretical analysis for the system.Firstly, a test rig about Chinese Kang system alone and solar Chinese Kang system combined with shutter-trombe wall is built. An experimental study on thermal performance of them is carried out to analyze the dynamic thermal response process of solar Chinese Kang, shutter-trombe and building and understand the heat transfer mechanisms of solar Chinese kang and shutter-trombe wall. Experimental analysis provides a reference for theoretical modelling. Secondly, dynamic mathematical models are presented for test rig and programs are developed for simulation. Models are validated by compare the theoretical results with the experiment results. The programs may analyze the thermal performance of system and the effects on indoor thermal environment and sleep thermal comfort dynamically. It provides the optimized analysis tools for thermal storage and heat discharge of solar Chinese Kang system, solar thermal systems and shutter-trobme wall.Thirdly, based on the validated model and typical meteorological data, indoor thermal environment and thermal comfort of sleep environment are studied when solar Kang system operating alone. At the same time, optimization analysis is carried out about operating mode of solar Kang and thermal collector system. On the other hand, optimization analysis is also accomplished about shutter-trombe wall. Results show that prioritization scheme is:pre-set inlet temperature of circulating water is greater than or equal to50℃(auxiliary power is turned off if inlet temperature is greater than50℃) and solar Kang is kept being heating from8am to5pm. And in this operating mode, PMV of sleeping environment value is between-0.52and0.41and solar fraction is0.598. Room air temperature keeps between7.8℃and13.7℃while average environment temperature is about0℃. For thermal storage of solar Kang, solar hot water tank of thermal collector system is the smaller the better. The air passages between shutter and south wall is best when the spacing is approximately0.05m.In summary, the studies in this thesis have provided some scientific basis and theories for study on the thermal performance of solar Kang and the application of solar Kang in the rural areas of northern China.