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Influence of thermodynamic disfigurement on the convective heat transfer of solar greenhouse

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International Journal of Agricultural and Biological Engineering 2020年第4期13卷 55-60页

作者： Yachen Sun Yanfei Cao Haotian Wang Changji Zhou Jinxin Xiao Chengyao Jiang Jianming Li Encai Bao Zhirong Zou Key Laboratory of Protected Horticultural Engineering in Northwest Ministry of Agriculture and Rural AffairsDepartment of HorticultureNorthwest A&F UniversityYangling 712100ShaanxiChina Academy of Agricultural Planning and Engineering Ministry of Agriculture and Rural AffairsBeijing 100125China Institute of Agricultural Facilities and Equipment Jiangsu Academy of Agricultural SciencesKey Laboratory of Protected Agriculture Engineering in the Middle and Lower Reaches of Yangtze RiverMinistry of Agriculture and Rural AffairsNanjing 210014China

solar greenhouse is a typical greenhouse without any additional heating system,which has developed rapidly in Northern ***,due to the construction quality,management methods,especially the long-term use and other factors,there are usually different degrees of thermodynamic disfigurements in the envelop enclosure of solar *** purpose of this study was to investigate the influences of thermodynamic disfigurement on the temperature distribution and convective heat transfer of solar *** this study,the east and west compartments of a typical solar greenhouse which is located in Yangling,China(108°4′E,34°16′N)were *** air temperature of each compartment was collected using temperature recorders,and the thermal infrared images of different compartment envelopes were obtained by a thermal infrared imager on a typical cloudy *** heat transfer coefficients and heat flux densities of different compartment envelopes in the solar greenhouse were *** results showed that the temperature difference can be displayed in the thermal infrared images of compartment envelopes,the surface temperature of the front roof was the lowest,followed by the back roof,the wall surface temperature was the *** minimum average surface temperature of the front roof in the eastern compartment was only 3.8℃,which was 6.8℃ and 9.2℃ lower than the average surface temperature of the back roof and back wall,*** surface average temperature of thermodynamic disfigurements located at the bottom of the south side in the front roof of the eastern compartment,whose area accounted for 16.5%of the total front roof in the eastern compartment,was only 5.4℃.Compared with non-thermodynamic disfigurement,the average convective heat transfer coefficient and heat flux density of thermodynamic disfigurements in the front roof of the eastern compartment were increased by 20.3%and 110.3%,*** average air temperature in the eastern com

关键词： solar greenhouse thermodynamic disfigurement convective heat transfer thermal infrared image

Improved root zone temperature buffer capacity enhancing sweet pepper yield via soil-ridged substrate-embedded cultivation in solar greenhouse

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International Journal of Agricultural and Biological Engineering 2018年第2期11卷 41-47页

作者： Guohai Fu Zonggeng Li Wenke Liu Qichang Yang Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences/Key Laboratory of Energy Conservation and Waste Management of Agricultural StructuresMinistry of AgricultureBeijing 100081China National Agricultural Technology Extension and Service Center Beijing 100125China

A novel soilless cultivation method,called as soil-ridged substrate-embedded cultivation(SSC)was invented,and an experiment was designed to investigate root zone temperature and production efficiency of sweet pepper cultivated by two SSC patterns,i.e.,SSC-P(polyethylene groove inserted)and SSC-W(wire-mesh groove inserted),and also other two cultivation methods,i.e.,soil ridge(SR)and naked polyethylene groove(PG).Results showed that PG,SSC-P and SSC-W increased the average minimal root zone temperature by 1.01℃,0.75℃,and 1.16℃ compared to SR(16.33℃)during March 16-20,*** June 1-5,SSC-P and SSC-W decreased the average maximal root zone temperature by 1.28℃ and 1.29℃ compared to SR(34.99℃),while PG increased it by 1.44℃.PG,SSC-P,and SSC-W decreased the differences of average daytime and night time temperatures by 1.34℃,2.13℃,and 2.88℃ compared to SR(4.56℃)during early ***,SSC-P and SSC-W decreased temperature differences of average daytime and night time by 0.9℃ and 1.07℃ compared to SR(0.95℃)during later stage,but PG improved by 2.85℃.Temperature difference of daytime and night time of SSC-W was minimal,and the temperature difference between the diurnal highest and the lowest temperature of SSC-W was also *** buffer capacity of SSC-W was slightly better than that of ***-W significantly improved the growth of sweet pepper compared to ***,fruit yield per square meter of sweet pepper cultivated on SSC-P and SSC-W improved by 21.24%and 50.33%,respectively compared to SR(3.06 kg/m^(2)),while PG lowered the yield by 13.72%.SSC-W was a better SSC pattern compared with SSC-P in terms of production efficiency.

关键词： soil cultivation SSC substrate cultivation solar greenhouse diurnal temperature difference root zone temperature

Sensitivity of solar greenhouse envelopes to the thermal disfigurements and optimal selection of the thermal insulation quilt

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International Journal of Agricultural and Biological Engineering 2021年第5期14卷 50-55页

作者： Yachen Sun Yao Zhang Chenmeng Zhu Shaonan Xu Bowen Liu Yanfei Cao Changji Zhou Yaqi Zhou Zhirong Zou Encai Bao College of Architecture and Urban Planning Tongji UniversityShanghai 200092China Institute of Agricultural Facilities and Equipment Jiangsu Academy of Agricultural ScienceKey Laboratory of Protected Agriculture Engineering in the Middle and Lower Reaches of Yangtze RiverMinistry of Agriculture and Rural AffairsNanjing 210014China School of Engineering Anhui Agricultural UniversityHefei 230036China Department of Management City University of Hong KongTat Chee Avenue KowloonHong Kong 999077China Qinghai College of animal husbandry and veterinary technology Xining 812100China School of Ocean and Earth Science Tongji UniversityShanghai 200092China Key Laboratory of Protected Horticultural Engineering in Northwest Ministry of Agriculture and Rural AffairsDepartment of HorticultureNorthwest A&F UniversityYangling 712100ShaanxiChina Academy of Agricultural Planning and Engineering Ministry of Agriculture and Rural AffairsBeijing 100125China School of Karst Science Guizhou Normal UniversityGuiyang 550001China

The objectives of the present work are focused on exploration of the reasons for temperature difference in different envelopes,the sensitivity of envelopes of solar greenhouse to thermal disfigurements and optimal selection of the thermal insulation *** analysis and derivation are conducted according to the experimental results of surface temperature,convective heat transfer,and heat flux density in different envelopes which with thermal disfigurements of solar greenhouse using heat transfer *** results revealed that the difference of intrinsic thermal conductivity and thickness of the envelopes leads to difference in the thermal flux and thus in the surface temperature of different *** with the front roof and back roof,the wall is more sensitive to thermal *** to the influence of thermal disfigurements on solar greenhouse temperature,the allowable thermal disfigurements area fraction of front roof and back roof are *** on the analysis of heat transfer theory and test results,the work given the expression of the thickness and thermal conductivity of thermal insulation quilt under different outdoor minimum temperatures for optimal selection of thermal insulation quilt based on comprehensive considering factors of the solar greenhouse structure,crop demand,outdoor minimum temperature,and insulation quilt *** results of this work give technical criterion for whether the envelopes with thermal disfigurements needs to be repaired or replaced,and it also provides theoretical and technical support for design the solar greenhouse as well as methodological guidance for the optimal selection of the thermal insulation quilt.

关键词： solar greenhouse thermal disfigurements optimal selection thermal insulation quilt

Two-stage seedling cultivation method for sweet peppers combining closed plant factory and solar greenhouse

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International Journal of Agricultural and Biological Engineering 2023年第6期16卷 56-66页

作者： Hongbo Cui Fang Ji Yanni Liu Zhengyang Luo Xiufeng Wang Jianfeng Wang Key Laboratory of Facility Vegetable of Jilin Province Jilin Academy of Vegetable and Flower SciencesChangchun 130119China Key Laboratory of Agricultural Engineering in Structure and Environment of MARA College of Water Resources&Civil EngineeringChina Agricultural UniversityBeijing 100083China College of Horticulture Jilin Agricultural UniversityChangchun 130033China

This study introduced a two-stage cultivation method for sweet pepper seedlings, integrating the strengths of a closed plant factory and solar greenhouse, to mitigate the environmental constraints in Northeast China during the early spring season. In the first stage, seedlings were cultivated in a closed plant factory, followed by a second stage in a solar greenhouse. Four treatments- T1 (9 and 36 d), T2 (12 and 33 d), T3 (15 and 30 d), and T4 (18 and 27 d) - were designed for the first and second stages, respectively, with solar greenhouse-only approach serving as the control (CK). The findings reveal that the two-stage methodology significantly outperformed the control across multiple metrics, including seedling health index, chlorophyll content, photosynthetic capacity, yield, etc. Specifically, T3 emerged as optimal, boosting the health index by 38.59%, elevating chlorophyll content by 39.61%, increasing net photosynthesis by 34.61%, and augmenting yield per plant by 40.67%. Additionally, T3 expedited the time to harvest by 25 d compared to the control. Although the seedling cost for T3 was 0.12 RMB yuan higher, the benefits offset the additional investment. In conclusion, the two-stage cultivation method effectively leverages the advantages of both closed-plant factories and solar greenhouses, resulting in superior seedling quality compared to using only solar greenhouses. It offers a practical and economically viable solution for enhancing the quality and yield of sweet pepper seedlings, thus contributing to the progress in the field of facility seedling cultivation research.

关键词： two-stage seedling cultivation sweet peppers closed plant factory solar greenhouse

Analysis of the thermal performance of the novel assembled Chinese solar greenhouse with a modular soil wall in winter of Yinchuan,China

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International Journal of Agricultural and Biological Engineering 2022年第5期15卷 70-77页

作者： Yanfei Cao Hongjun Xu Miao Shi Xueyan Zhang Yahong Zhang Zhirong Zou College of Horticulture Northwest A&F UniversityYangling 712100ShaanxiChina Key Laboratory of Protected Horticulture Engineering in Northwest Ministry of Agriculture and Rural AffairsYangling 712100ShaanxiChina College of Horticulture Xinjiang Agricultural UniversityUrumqi 830052China School of Agriculture Ningxia UniversityYinchuan 750021China

In order to improve the thermal insulation and storage performance of Chinese solar greenhouses in winter,a novel assembled Chinese solar greenhouse(ACSG)without energy supplement in cold climatic areas was designed to evaluate and compare its thermal performance with that of conventional Chinese solar greenhouse(CSG).The thermal properties of both greenhouses were tested in field on cold winter days in Ningxia,*** results indicated that the land utilization rate of ACSG was 19.3%higher than that of *** a typical sunny day(the lowest outdoor temperature was−22.0℃)and typical cloudy day(the lowest outdoor temperature was−19.7℃)during the experiment,the minimum indoor temperature of ACSG was respectively 1.7℃and 2.0℃higher than that of *** results for 24 consecutive days(the average outdoor daily minimum air temperature was−19.0℃)showed that the average minimum indoor temperature of ACSG was 1.4℃higher than that of CSG(p<0.05).The modular soil wall attached with colored steel polystyrene boards would be exploited as the north wall of CSG in Yinchuan area.

关键词： thermal performance solar greenhouse north wall composite wall structure soil block

Effects of window opening style on inside environment of solar greenhouse based on CFD simulation

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International Journal of Agricultural and Biological Engineering 2020年第6期13卷 53-59页

作者： Yachen Sun Encai Bao Chenmeng Zhu Lulu Yan Yanfei Cao Xuanhe Zhang Jianming Li Haiwei Jing Zhirong Zou Key Laboratory of Protected Horticultural Engineering in Northwest Ministry of AgricultureDepartment of HorticultureNorthwest A&F UniversityYangling 712100ShaanxiChina Institute of Agricultural Facilities and Equipment Jiangsu Academy of Agricultural ScienceKey Laboratory of Protected Agriculture Engineering in the Middle and Lower Reaches of Yangtze RiverMinistry of Agriculture and Rural AffairsNanjing 210014China College of Management City University of Hong KongTat Chee AvenueKowloon 999077Hong KongChina Department of Horticulture Xinyang Agriculture and Forestry UniversityXinyang 464000HenanChina Department of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100ShaanxiChina

solar greenhouse is extensively used in horticultural production in *** ventilation is one of the key technological means to adjust the inside environment of greenhouse,while the effects of window opening styles on the inside environment are still not well *** the present study,the temperature and air flow field of five operation styles,namely back roof central opening style(G1),back roof evenly spaced opening style(G2),top roof full opening style(G3),style of G1+G3,and style of G2+G3 were simulated using the CFD *** results indicated that:(1)the simulated and measured results exhibited favorable agreement,with relative errors within 5%;(2)In the case of the windows opening area was the same and only single ventilation style was applied,back roof full opening style exhibited the best cooling *** inside average temperature of the greenhouse with G1 style decreased by 0.5°C and 1.6°C respectively compared with those of greenhouses with G2 and G3.(3)The cooling effect of the style of G2+G3 was more favorable than that of the style of G1+*** style of G2+G3 exhibited better cooling effect than the single ventilation styles,with the lowest temperature(27.5°C)and temperature uniformity coefficient(0.36).

关键词： CFD modeling window opening styles cooling effects solar greenhouse

Effects of Light and Temperature on Uptake andDistribution of Nitrogen, Phosphorus and Potassiumof Cucumber in solar greenhouse

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Agricultural Sciences in China 2002年第11期1卷 1246-1250页

作者： PEI Xiao-bo, ZHANG Fu-man and WANG Liu(College of Horticulture, China Agricultural University , Beijing 100094 , P. R. China) College of Horticulture China Agricultural University Beijing 100094P.R.China

The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing.

关键词： Cucumber solar greenhouse Light and temperature conditions Nutrient Uptake Distribu-tion

Determination and Analysis on Heat of Trapezoidal Soil Wall in solar greenhouse

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Agricultural Science & Technology 2017年第12期18卷 2596-2602页

作者： Qing BAI Yahong ZHANG Lixin Sun Meiqi FEN Ningxia University Yinchuan 750021China Ningxia Institute of Technology for Development and Information Study Yinchuan 750021China

solar greenhouse with trapezoidal soil wall is widely used due to its good heat retaining property and cost *** this study, solar irradiance, heat flux and the temperature 0.05 and 0.3 m from the inner surface of the wall at the upper,middle and lower measured positions were determined to study the thermal condition of the trapezoidal soil wall in solar greenhouse. The results showed: first, both the solar irradiance and the temperature increased from the upper to the lower measured position. Second, the heat absorption also increased from the upper to the lower measured position. In clear day, the heat absorption at the three measured positions accounted for 31.4%, 32.6% and 36.0% of the total amount of heat absorption of the whole wall. In cloudy day, the heat absorption at the three measured positions were 0.249, 0.370 and 0.440 MJ/m^2, which accounted for 23.5%, 35.0% and 41.4% of the total amount of heat absorption of the whole wall. When Psolar irradiance directly influenced the heat absorption and had close relation with heat emission. And heat emission again had close relation with the temperature in t

关键词： solar greenhouse Soil Wall Heat

Design of Diversified Intelligent Control System for Energy-saving Optimization of solar greenhouse in North China

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Asian Agricultural Research 2023年第7期15卷 45-50,53页

作者： Yanmeng HE Baohui MA Yiyang Vocational and Technical College Yiyang 413000China Gansu Tianshui Electric Drive Research Institute Tianshui 741000China

Intelligent greenhouse can promote the development of modern agriculture, realize the high quality and high yield of crops, and also bring greater economic benefits. In accordance with the climate conditions in northwest China, a set of intelligent control system for diversified environment of solar greenhouse was designed. The system divides the annual greenhouse control into six stages according to the optimal energy saving. It uses modern detection technology to collect the greenhouse environmental temperature, environmental humidity, soil humidity, CO_(2) concentration and illumination parameters under different working modes. It uses programmable logic control technology to realize the data processing of various parameters and the action control of rolling film, wet curtain fan and other actuators. It uses KingView monitoring software to realize the monitoring and manual control of greenhouse environment parameters. The operation results indicate that the control system runs stably and basically meets the control requirements.

关键词： solar greenhouse Energy-saving optimization Diversified Control Intelligent control