喷雾降温联合自然通风在大跨度温室中的试验
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摘要
为提高日光温室土地利用率、增大日光温室操作空间,设计了一种新型南北走向的大跨度温室。该温室在夏天种植作物时,室内温度较高,尤其在晴天,即便通风口全开进行自然通风,中午温室内温度亦可高达40℃以上。为降低大跨度温室内温度,该文提出了一种高压喷雾降温方法,高压喷雾装置由过滤器、储水箱、管道、高压泵、控制器解压阀和喷头组成。根据现有的研究理论,计算温室的喷雾量为0. 27 g/(m~2·s),选择锥心式喷头,喷头孔径为0. 3 mm,雾滴直径为0. 02~0. 03 m,喷头流量为1. 3~2. 4 g/s,喷头安装密度为0. 3个/m~2。试验期间设置了60 s开300 s关、90 s开300 s关和120 s开300 s关的3种喷雾运行模式,并在夏季典型晴天开展了喷雾降温试验,选择室外环境差异小的3个典型晴天的3个时段进行比较。试验结果表明,3种喷雾系统运行模式下,试验温室与对照温室相比,气温分别要低3. 0、5. 1和6. 0℃,空气相对湿度分别增加10. 2%、20. 1%和23. 8%。同等室外环境条件下,3种喷雾系统运行模式下的喷雾蒸发冷却效率分别为26. 3%、39. 4%和47. 2%,从降温效果、空气相对湿度增加量及喷雾蒸发冷却效率结合来看,系统运行120 s关闭300 s的喷雾模式的降温效果最为理想。综合认为,该研究为北方大跨度温室夏季降温调控奠定了基础。
In order to increase land use efficiency and operation space of solar greenhouse,a new type of long-span greenhouse with north-south trend was designed. When planting crops in summer,the indoor temperature of the greenhouse is higher,especially in sunny days. Even if ventilation vents are fully opened for natural ventilation,temperature in the greenhouse at noon can be as high as 40 ℃. In order to reduce temperature in a large span greenhouse,a high-pressure spray cooling method was proposed. The high-pressure spray device consisted of a filter,a storage tank,a pipeline,a high-pressure pump,a controller decompression valve and a sprinkler. According to previous research theory,spray volume of greenhouse was calculated to be 0. 27 g/( m~2·s),the nozzle was cone shaped,nozzle diameter was 0. 3 mm,droplet diameter was 0. 02 ~0. 03 m,nozzle flow rate was 1. 3 ~ 2. 4 g/s,and nozzle mounting density was 0. 3 /m~2. During the test period,3 spray operation modes,60 s opening 300 s off,90 s 300 s off and 120 s opening 300 s off,were set up,and spray cooling experiments were conducted on typical sunny days in summer. Test results showed that temperature of experimental greenhouse was 3. 0,5. 1 and 6. 0 ℃ lower than that of control greenhouse respectively under three operation modes of spray device,and relative humidity of air increased by 10. 2%,20. 1%and 23. 8% respectively. Spray evaporative cooling efficiency of three spray operation modes was 26. 3%,39. 4% and 47. 2% respectively under outdoor environment approaching condition. Combined with cooling effect of greenhouse,relative humidity of air and efficiency of spray evaporative cooling,cooling effect of 120 s intermittent 300 s spray system was ideal. It was concluded that this study provided a reference for regulation of summer cooling in large-span greenhouses in North China.
In order to increase land use efficiency and operation space of solar greenhouse,a new type of long-span greenhouse with north-south trend was designed. When planting crops in summer,the indoor temperature of the greenhouse is higher,especially in sunny days. Even if ventilation vents are fully opened for natural ventilation,temperature in the greenhouse at noon can be as high as 40 ℃. In order to reduce temperature in a large span greenhouse,a high-pressure spray cooling method was proposed. The high-pressure spray device consisted of a filter,a storage tank,a pipeline,a high-pressure pump,a controller decompression valve and a sprinkler. According to previous research theory,spray volume of greenhouse was calculated to be 0. 27 g/( m~2·s),the nozzle was cone shaped,nozzle diameter was 0. 3 mm,droplet diameter was 0. 02 ~0. 03 m,nozzle flow rate was 1. 3 ~ 2. 4 g/s,and nozzle mounting density was 0. 3 /m~2. During the test period,3 spray operation modes,60 s opening 300 s off,90 s 300 s off and 120 s opening 300 s off,were set up,and spray cooling experiments were conducted on typical sunny days in summer. Test results showed that temperature of experimental greenhouse was 3. 0,5. 1 and 6. 0 ℃ lower than that of control greenhouse respectively under three operation modes of spray device,and relative humidity of air increased by 10. 2%,20. 1%and 23. 8% respectively. Spray evaporative cooling efficiency of three spray operation modes was 26. 3%,39. 4% and 47. 2% respectively under outdoor environment approaching condition. Combined with cooling effect of greenhouse,relative humidity of air and efficiency of spray evaporative cooling,cooling effect of 120 s intermittent 300 s spray system was ideal. It was concluded that this study provided a reference for regulation of summer cooling in large-span greenhouses in North China.
引文
[1]李强.现代化农业温室的夏季降温研究及其发展[J].环境科学进展,1999(1):41-44.
[2]王海廷.番茄生理基础[M].上海:上海科学技术出版社,1981.
[3]方慧,杨其长,张义,等.基于CFD技术的日光温室自然通风热环境模拟[J].中国农业气象,2015,36(2):155-160.FANG Hui,YANG Qichang,ZHANG Yi,et al. Simulation performance of a ventilated greenhouse based on CFD technology[J].Chinese Journal of Agrometeorology,2015,36(2):155-160.
[4]方慧,杨其长,张义,等.日光温室热压风压耦合自然通风流量的模拟[J].中国农业气象,2016,37(5):531-537.FANG Hui, YANG Qichang, ZHANG Yi, et al. Simulation on ventilation flux of solar greenhouse based on the coupling between stack and wind effects[J]. Chinese Journal of Agrometeorology,2016,37(5):531-537.
[5] GANGULY A,GHOSH S. Model development and experimental validation of a floriculture greenhouse under natural ventilation[J].Energy&Buildings,2009,41(5):521-527.
[6]李本卿.强制通风条件下Venlo型温室内气流场和温度场的CFD数值模拟研究[D].镇江:江苏大学,2009.LI Benqing. CFD numerical simulation of airflow and temperature distribution in Venlo greenhouse under mechanical ventilation[D].Zhenjiang:Jiangsu University,2009.
[7]胥芳,蔡彦文,陈教料,等.湿帘-风机降温下的温室热流场模拟及降温系统参数优化[J].农业工程学报,2015,31(9):201-208.XU Fang,CAI Yanwen,CHEN Jiaoliao,et al. Temperatureflow field simulation and parameter optimal design for greenhouses with fan-pad evaporative cooling system[J]. Transactions of the Chinese Society of Agricultural Engineering,2015,31(9):201-208.
[8]王蕊,须晖,马健,等.基于流体力学的湿帘风机温室内气流运动的模拟分析[J].农业工程学报,2011,27(6):250-255.WANG Rui,XU Hui, MA Jian, et al. CFD analysis of airflow distribution in greenhouse with pad and fan cooling system[J].Transactions of the Chinese Society of Agricultural Engineering,2011,27(6):250-255.
[9] FRANCO A,VALERA D L,PENA,et al. Aerodynamic analysis and CFD simulation of several cellulose evaporative cooling pads used in Mediterranean greenhouses[J]. Computers and Electronics in Agriculture,2011,76(2):218-230.
[10]王吉庆,张百良.几种降温措施在温室夏季降温中的应用研究[J].农业工程学报,2006,22(9):257-260.WANG Jiqing, ZHANG Bailiang. Application of some cooling measures for greenhouse cooling in summer[J]. Transactions of the Chinese Society of Agricultural Engineering,2006,22(9):257-260.
[11]程绍明,楼华粱,崔绍荣.连栋塑料温室喷雾降温及外遮荫降温试验研究[J].农机化研究,2004,26(2):169-171.CHENG Shaoming, LOU Hualiang, CUI Shaorong. Experimental research on cooling system in the multi-span plastic greenhouse[J].Journal of Agricultural Mechanization Research,2004,26(2):169-171.
[12]沈明卫,陈志银,苗香雯.连栋温室遮阳网上喷雾降温性能研究[J].农业机械学报,2003,34(2):65-68.SHEN Mingwei,CHEN Zhiyin,MIAO Xiangwen. Performance of spray cooling on sun shading net of multi-span greenhouse[J].Transactions of the Chinese Society of Agricultural Machinery.2003,34(2):65-68.
[13]万正林,李立志,邓俭英,等.南方农业设施常用降温方法及其基本原理[J].广西农业科学,2010,41(7):739-741.WAN Zhenglin, LI Lizhi, DENG Jianyin, et al. Conventional cooling methods for agriculture facilities in southern China and their basic principles[J]. Guangxi Agricultural Sciences, 2010, 41(7):739-741.
[14] BAPTISTA F J,BAILEY B J,RANDALL J M,et al. Greenhouse ventilation rate:theory and measurement with tracer gas techniques[J]. Journal of Agricultural Engineering Research,1999,72(4):363-374.
[15] ABDEL-GHANY A M,KOZAI T. Cooling efficiency of fogging systems for greenhouses[J]. Biosystems Engineering,2006,94(1):97-109.
[16] OZTURK H H. Evaporative cooling efficiency of a fogging system for greenhouse[J]. Turk Journal of Agricultural Forestry,2003,27:49-57.
[17] LI S,WILLITS D H. Comparing low-pressure and high-pressure fogging systems in naturally ventilated greenhouses[J]. Biosystems Engineering,2008,101(1):69-77.
[18]吴振海,陈家金,徐宗焕.遮阳网的小气候效应及其对蔬菜生长的影响[J].福建农业大学学报,2001,30(2):185-190.WU Zhenhai, CHEN Jiajin, XU Zonghuan. Micro-climate effect of sun shading-net and its influence on vegetable growth[J]. Journal of Fujian Agricultural University,2001,30(2):185-190.
[19]沈明卫,郝飞麟.内外遮阳对连栋塑料温室内光环境的影响[J].农业机械学报,2004,35(5):110-116.SHEN Mingwei,HAO Feilin. Effects of inner and outer sun shading net on solar radiation inside multi-span greenhouse[J]. Journal of Agricultural Mechanization Research,2004,35(5):110-116.
[20] YAN Q Y,LIU H C,CHEN R Y. Effects of different shading-net on growth and quality of flowering Chinese cabbage[J]. Acta Horticulturae,2011(907):199-203.
[21]韩丽蓉,王宏丽,李凯,等.下沉式大跨度大棚型温室的设计及应用研究[J].中国农业大学学报,2014,19(4):161-165.HAN Lirong,WANG Hongli,LI Kai et al. Design and application study on the sinking and great-span greenhouse without back wall[J]. Journal of China Agricultural University,2014,19(4):161-165.
[22]赵纯清,张继元.温室除湿降温系统中除湿温室结构的设计[J].华中农业大学学报,2004,23(3):355-358.ZHAO Chunqing,ZHANG Jiyuan. Study on construction designing about the dehumidifying room and cooling system for greenhouse[J].Journal of Huazhong Agricultural University,2004,23(3):355-358.
[23] LI Y X,LI B M,WANG C Y,et al. Effects of shading and roof sprinkling in Venlo-type greenhouse in summer[J]. Transactions of the Chinese Society of Agricultural Engineering,2002,18(5):127-130.
[24]马承伟,苗香雯.农业生物环境工程[M].北京:中国农业出版社,2004.
[25]周长吉.温室工程设计手册[M].北京:中国农业出版社,2007.
[26] ABDEL-GHANY A M,KOZAI T. Cooling efficiency of fogging system for greenhouses[J]. Biosystems Engineering, 2006, 94(1):97-109.
[2]王海廷.番茄生理基础[M].上海:上海科学技术出版社,1981.
[3]方慧,杨其长,张义,等.基于CFD技术的日光温室自然通风热环境模拟[J].中国农业气象,2015,36(2):155-160.FANG Hui,YANG Qichang,ZHANG Yi,et al. Simulation performance of a ventilated greenhouse based on CFD technology[J].Chinese Journal of Agrometeorology,2015,36(2):155-160.
[4]方慧,杨其长,张义,等.日光温室热压风压耦合自然通风流量的模拟[J].中国农业气象,2016,37(5):531-537.FANG Hui, YANG Qichang, ZHANG Yi, et al. Simulation on ventilation flux of solar greenhouse based on the coupling between stack and wind effects[J]. Chinese Journal of Agrometeorology,2016,37(5):531-537.
[5] GANGULY A,GHOSH S. Model development and experimental validation of a floriculture greenhouse under natural ventilation[J].Energy&Buildings,2009,41(5):521-527.
[6]李本卿.强制通风条件下Venlo型温室内气流场和温度场的CFD数值模拟研究[D].镇江:江苏大学,2009.LI Benqing. CFD numerical simulation of airflow and temperature distribution in Venlo greenhouse under mechanical ventilation[D].Zhenjiang:Jiangsu University,2009.
[7]胥芳,蔡彦文,陈教料,等.湿帘-风机降温下的温室热流场模拟及降温系统参数优化[J].农业工程学报,2015,31(9):201-208.XU Fang,CAI Yanwen,CHEN Jiaoliao,et al. Temperatureflow field simulation and parameter optimal design for greenhouses with fan-pad evaporative cooling system[J]. Transactions of the Chinese Society of Agricultural Engineering,2015,31(9):201-208.
[8]王蕊,须晖,马健,等.基于流体力学的湿帘风机温室内气流运动的模拟分析[J].农业工程学报,2011,27(6):250-255.WANG Rui,XU Hui, MA Jian, et al. CFD analysis of airflow distribution in greenhouse with pad and fan cooling system[J].Transactions of the Chinese Society of Agricultural Engineering,2011,27(6):250-255.
[9] FRANCO A,VALERA D L,PENA,et al. Aerodynamic analysis and CFD simulation of several cellulose evaporative cooling pads used in Mediterranean greenhouses[J]. Computers and Electronics in Agriculture,2011,76(2):218-230.
[10]王吉庆,张百良.几种降温措施在温室夏季降温中的应用研究[J].农业工程学报,2006,22(9):257-260.WANG Jiqing, ZHANG Bailiang. Application of some cooling measures for greenhouse cooling in summer[J]. Transactions of the Chinese Society of Agricultural Engineering,2006,22(9):257-260.
[11]程绍明,楼华粱,崔绍荣.连栋塑料温室喷雾降温及外遮荫降温试验研究[J].农机化研究,2004,26(2):169-171.CHENG Shaoming, LOU Hualiang, CUI Shaorong. Experimental research on cooling system in the multi-span plastic greenhouse[J].Journal of Agricultural Mechanization Research,2004,26(2):169-171.
[12]沈明卫,陈志银,苗香雯.连栋温室遮阳网上喷雾降温性能研究[J].农业机械学报,2003,34(2):65-68.SHEN Mingwei,CHEN Zhiyin,MIAO Xiangwen. Performance of spray cooling on sun shading net of multi-span greenhouse[J].Transactions of the Chinese Society of Agricultural Machinery.2003,34(2):65-68.
[13]万正林,李立志,邓俭英,等.南方农业设施常用降温方法及其基本原理[J].广西农业科学,2010,41(7):739-741.WAN Zhenglin, LI Lizhi, DENG Jianyin, et al. Conventional cooling methods for agriculture facilities in southern China and their basic principles[J]. Guangxi Agricultural Sciences, 2010, 41(7):739-741.
[14] BAPTISTA F J,BAILEY B J,RANDALL J M,et al. Greenhouse ventilation rate:theory and measurement with tracer gas techniques[J]. Journal of Agricultural Engineering Research,1999,72(4):363-374.
[15] ABDEL-GHANY A M,KOZAI T. Cooling efficiency of fogging systems for greenhouses[J]. Biosystems Engineering,2006,94(1):97-109.
[16] OZTURK H H. Evaporative cooling efficiency of a fogging system for greenhouse[J]. Turk Journal of Agricultural Forestry,2003,27:49-57.
[17] LI S,WILLITS D H. Comparing low-pressure and high-pressure fogging systems in naturally ventilated greenhouses[J]. Biosystems Engineering,2008,101(1):69-77.
[18]吴振海,陈家金,徐宗焕.遮阳网的小气候效应及其对蔬菜生长的影响[J].福建农业大学学报,2001,30(2):185-190.WU Zhenhai, CHEN Jiajin, XU Zonghuan. Micro-climate effect of sun shading-net and its influence on vegetable growth[J]. Journal of Fujian Agricultural University,2001,30(2):185-190.
[19]沈明卫,郝飞麟.内外遮阳对连栋塑料温室内光环境的影响[J].农业机械学报,2004,35(5):110-116.SHEN Mingwei,HAO Feilin. Effects of inner and outer sun shading net on solar radiation inside multi-span greenhouse[J]. Journal of Agricultural Mechanization Research,2004,35(5):110-116.
[20] YAN Q Y,LIU H C,CHEN R Y. Effects of different shading-net on growth and quality of flowering Chinese cabbage[J]. Acta Horticulturae,2011(907):199-203.
[21]韩丽蓉,王宏丽,李凯,等.下沉式大跨度大棚型温室的设计及应用研究[J].中国农业大学学报,2014,19(4):161-165.HAN Lirong,WANG Hongli,LI Kai et al. Design and application study on the sinking and great-span greenhouse without back wall[J]. Journal of China Agricultural University,2014,19(4):161-165.
[22]赵纯清,张继元.温室除湿降温系统中除湿温室结构的设计[J].华中农业大学学报,2004,23(3):355-358.ZHAO Chunqing,ZHANG Jiyuan. Study on construction designing about the dehumidifying room and cooling system for greenhouse[J].Journal of Huazhong Agricultural University,2004,23(3):355-358.
[23] LI Y X,LI B M,WANG C Y,et al. Effects of shading and roof sprinkling in Venlo-type greenhouse in summer[J]. Transactions of the Chinese Society of Agricultural Engineering,2002,18(5):127-130.
[24]马承伟,苗香雯.农业生物环境工程[M].北京:中国农业出版社,2004.
[25]周长吉.温室工程设计手册[M].北京:中国农业出版社,2007.
[26] ABDEL-GHANY A M,KOZAI T. Cooling efficiency of fogging system for greenhouses[J]. Biosystems Engineering, 2006, 94(1):97-109.