| The rapid development of economy and the improvement of people's living standards have driven the growth of building energy consumption and carbon emissions.In this paper,a hollow-ventilated interior wall(HVIW)system coupled with solar energy is used to heat ordinary residential buildings in alpine regions.Using the heat storage characteristics of the inner envelope structure to enhance the comfort of the room with clean solar energy,its energy saving and high efficiency are very significant.Firstly,the paper analyzes the various processes of heat transfer in the hollow-ventilated interior wall,and obtains the heat transfer coefficient and heat transfer between the circulating hot air in the cavity and the inner wall surface.The convection and radiative heat transfer between the outer wall and the indoor air.Aiming at the heat storage and release process of the wall,the parameters such as heat storage efficiency,cumulative heat release from the wall during the non-heating period of the wall and heat release efficiency were evaluated.Secondly,an experimental room with a hollow-ventilated inner wall structure was built.After designing the experimental scheme,9 sets of steady state and 4 sets of dynamic state experiments were carried out by changing the conditions of supply air temperature and supply speed.Combined with the previous theoretical analysis,it is found that the convective heat transfer coefficient between the cavity and the inner wall doesn't change with the difference of the supply air temperature when the wind speed is constant,it increases with the wind speed.The natural convective heat transfer coefficient between the outer wall and the indoor varies from 2.88 to 3.54 W/(m~2·K),and the radiation heat transfer coefficient varies from 5.43 to 5.55W/(m~2·K).The total coefficient is 8.32 to 9.09 W/(m~2·K).It can be seen from the dynamic state experiment that the wall is continuously exothermic to the room throughout the day,and the ratio of the non-heating period to the cumulative heating amount is more than 40%,indicating that the system has a certain heat storage capacity.Then based on the experimental wall,a numerical calculation model was established.The experimental results were compared with the numerical calculations to verify the rationality of the numerical calculation method and model.The influencing factors of the thermal storage performance of the internal wall were analyzed by using the calculated calculation method and model,including the cavity structure,cavity thickness and wall thickness,air supply mode,heating time,air supply temperature and the addition of metal ribs in the wall,etc.The results show that the increase of the number of cavity baffles can make the heat transfer more uniform,but increase the transportation energy consumption of the system with an exponential growth trend;The increase of the thickness of the cavity,the thickness of the solid layer of the inner wall and the addition of metal foil to the inner wall can reduce the temperature fluctuates of the outer wall surface,and the heat release and heat release efficiency of the non-heating section time increase,which means the heat storage performance of the wall is improved.The cumulative heat release throughout the day will decrease with the increase of the thickness of the cavity,while it will not change with the thickness of the inner wall solid layer,and the metal foil of different widths can increase it by 2.02%,6.81%and 9.03%respectively;There are no differences in the heat transfer process with different air supply mode;The increase of the air supply time can not only greatly increase the cumulative heat release throughout the day,but also can increase the heat release efficiency,and the increase of the heat release efficiency decreases with the heating time;The use of fluctuating supply air temperature and intermittent operation of the fan will increase the cumulative heat release throughout the day and the cumulative heat release during the non-heating period. |
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