| Solar energy resource is rich in alpine region in China,it has the potential of large-scale exploitation and utilization.It is important development direction for urban construction in alpine region to use the abundant solar resources in order to build low-energy plateau construction.The technology of passive solar power is regarded as the most suitable way of solar energy for plateau construction because of its maintenance free,convenient operation and energy saving.However,it is difficult to solve contradiction for the traditional utilization way of passive solar energy(benefit directly window,trombe wall,sunspace)that between small thermal resistance of use requirements of the south palisade structure and big thermal resistance of insulation requirements of the palisade structure,and it causes the inefficiency of actual project application.In order to overcome the traditional passive solar technology,this paper adopts a new combined passive solar energy program,it effectively improves the indoor thermal environment in alpine region.The paper solves the mechanism of dynamic regulation of indoor thermal environment based on step heat transfer characteristics.Besides,the paper builds the optimized design scheme of transparent envelope in the light of theoretical research.The technology can provide guidance for the further application.First of all,the physical model and working principle of adjustable transparent envelope is expounded.The technology not only solve the limitation of traditional benefit directly window,but also come true step heat transfer characteristics,this characteristics mainly reflects in: during the day,the solar heat gain coefficient(SHGC)can step up,the thermal resistance of envelope go down,it makes room gain solar energy easily;during the night,the thermal resistance of the benefit directly window steps down,and the thermal resistance of envelope is promoted,it makes the solar energy can be saved.Secondly,according to the physical model of adjustable transparent envelope,this paper focuses on the differentiation mechanism of heat transfer,which is mainly reflected in the dynamic heat transfer process on the different control strategies of day and night.The key design parameters of adjustable transparent envelope is determined through the establishment of mathematical model and analysis of the data:(1)50-60 mm intervenes between the inside of the insulating glass and the outside of the insulating glass.(2)50-60 mm intervenes between the inside of the insulating glass and inner curtain.(3)To identify the best control strategy in the area: opening the insulating glass at 9:00a.m.and closing the insulating glass at 18:00 p.m.(4)South to partial west and east within 20 ° can be calculated at south for solar radiation heat gain.Then,the paper builds consumption model about ‘warm nest’ project based on DesignBuilder simulation software in order to test the application effect of adjustable transparent envelope.Through the all-year hourly dynamic simulation,the paper researches adjustable transparent envelope technology respectively from the application effect,influence factors and the optimization design and so on.(1)The average temperature of outdoor is under 2.1℃,the average room temperature > 15.0℃,it shows the application effect of adjustable transparent envelope is obvious.(2)The inside of the insulating glass uses XPS insulation board,compared with double glasses,room temperature is about 1.4 ℃ higher than that of using XPS effect is better.(3)Solar radiation and windows are the most important factors for temperature up or down in the room.The evaluation system of adjustable transparent envelope is established based on the analysis of theoretical model and numerical simulation.Finally,the accuracy of numerical simulation is verified by on-site test.Test results show that(1)In reasonably using the variable transmission under the condition of retaining structure control strategy,indoor average temperature at 12.5 ℃-14 ℃(outdoor temperature:-12.5℃-10℃),indoor thermal environment in good condition,heat preservation effect is obvious;Adjustable transparent envelope is greatly influenced by control strategy,in the daytime if not open the inside of the insulating glass,indoor average temperature will be lower than open room all day about 5.8 ℃or so,most greatly influence the indoor thermal comfort.(3)The conclusion of the cloudy day also should use the same control strategy.The research results provide the theoretical support and development direction for the application of the adjustable transparent envelope. |
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