In order to explore the influence of water velocity on the heat collection performance of the active heat storage and release system for solar greenhouses,six different flow rates were selected for treatment in this e...In order to explore the influence of water velocity on the heat collection performance of the active heat storage and release system for solar greenhouses,six different flow rates were selected for treatment in this experiment.The comprehensive heat transfer coefficient of the active heat storage and release system at the heat collection stage was calculated by measuring the indoor solar radiation intensity,indoor air temperature and measured water tank temperature.The prediction model of water temperature in the heat collection stage was established,and the initial value of water temperature and the comprehensive heat transfer coefficient were input through MATLAB software.The simulated value of water temperature was compared with the measured value and the results showed that the best heat transfer effect could be achieved when the water flow speed was 1.0 m3h-1.The average relative error between the simulated water tank temperature and the measured value is 2.70-6.91%.The results indicate that the model is established correctly,and the variation trend of water temperature can be predicted according to the model in the heat collection stage.展开更多
Solar greenhouses have been widely developed in China.Active heat storage walls using air ducts arranged in the walls can improve the walls'thermal performance and indoor temperatures of solar greenhouses.In the p...Solar greenhouses have been widely developed in China.Active heat storage walls using air ducts arranged in the walls can improve the walls'thermal performance and indoor temperatures of solar greenhouses.In the present work,three kinds of air duct layouts,namely straight-up-and-down duct(Z),fork-shaped top-in-bottom-out distribution duct(DF),and“±”-shaped top-in-side-out distribution duct(CF)are designed.The effect of the three air duct layouts on the heat transfer and storage characteristics of the back wall is studied using the computational fluid dynamics(CFD)method.Results show that after the same time period,the transferred heat amount in the back wall with duct DF is the largest,while that with duct CF is slightly greater than that with duct Z.The temperature of the back walls with air ducts is higher than that without air ducts.The air duct DF is the optimal among the three kinds of air duct layouts.The greenhouse with the duct DF in the back wall shows the most obviously increased indoor average temperature,the highest temperature at night,and the most uniform temperature.展开更多
基金National Natural Science Foundation of Sichuan Province(Project No.:2022NSFSC1645)Key R&D Program Project of Xinjiang Province(Project No.:2023B02020)National Agricultural Science and Technology Innovation System Sichuan Characteristic Vegetable Innovation Team Project,Sichuan Innovation Team Program of CARS(Project No.:SCCXTD-2024-22)。
文摘In order to explore the influence of water velocity on the heat collection performance of the active heat storage and release system for solar greenhouses,six different flow rates were selected for treatment in this experiment.The comprehensive heat transfer coefficient of the active heat storage and release system at the heat collection stage was calculated by measuring the indoor solar radiation intensity,indoor air temperature and measured water tank temperature.The prediction model of water temperature in the heat collection stage was established,and the initial value of water temperature and the comprehensive heat transfer coefficient were input through MATLAB software.The simulated value of water temperature was compared with the measured value and the results showed that the best heat transfer effect could be achieved when the water flow speed was 1.0 m3h-1.The average relative error between the simulated water tank temperature and the measured value is 2.70-6.91%.The results indicate that the model is established correctly,and the variation trend of water temperature can be predicted according to the model in the heat collection stage.
基金financially supported by the National Natural Science Foundation of China(31901420)Jiangsu Provincial Natural Science Foundation(Grant No.BK20241174)Key Research and Development Program Project of Ningxia Hui Autonomous Region(2023BCF01022).
文摘Solar greenhouses have been widely developed in China.Active heat storage walls using air ducts arranged in the walls can improve the walls'thermal performance and indoor temperatures of solar greenhouses.In the present work,three kinds of air duct layouts,namely straight-up-and-down duct(Z),fork-shaped top-in-bottom-out distribution duct(DF),and“±”-shaped top-in-side-out distribution duct(CF)are designed.The effect of the three air duct layouts on the heat transfer and storage characteristics of the back wall is studied using the computational fluid dynamics(CFD)method.Results show that after the same time period,the transferred heat amount in the back wall with duct DF is the largest,while that with duct CF is slightly greater than that with duct Z.The temperature of the back walls with air ducts is higher than that without air ducts.The air duct DF is the optimal among the three kinds of air duct layouts.The greenhouse with the duct DF in the back wall shows the most obviously increased indoor average temperature,the highest temperature at night,and the most uniform temperature.
