【作者】 白义奎；

【导师】 迟道才；

【作者基本信息】 沈阳农业大学 ， 农业水土工程， 2007， 博士

【摘要】 在冬季，为保证在出现极端天气条件下日光温室能够正常生产，一般都采取了人工加温的方式。目前常用的加温方式有热水加温系统、热风炉加温系统、电加热系统、电热泵等，采用的主要能源为燃煤、燃油、燃气以及电能，设备费用高，运行费用高，使得其应用受到很大程度的限制。日光温室燃池．地中热交换系统将日光温室燃池加热系统、地中热交换系统有机结合起来，通过系统的运行，提高地温、温室内气温，并能有效的降低温室内湿度。在冬季白天，通过风机、地下热交换管道进行循环，把燃池释放出来的热量传入地下，贮存起来，以达到提高地温的目的；夜间通过风机、地中热交换管道及地上管道，把燃池释放的热量、白天贮存到地下的热量释放到空气中，达到提高气温及降低空气湿度的目的。在夏季，当温室内的空气温度较高时，通过风机、地中热交换管道进行循环，达到降低温室内空气温度的目的。本研究的主要内容包括：(1)分析目光温室燃池-地中热交换系统的传热机理，根据对流、传导及辐射的传热理论，建立日光温室燃池-地中热交换系统热量传递的数理模型，并进行数值分析；(2)根据模型分析日光温室燃池-地中热交换系统的结构参数对系统热工性能的影响，在此基础上进行结构参数的技术经济优化，设计日光温室燃池-地中热交换系统结构；(3)通过试验分析日光温室燃池-地中热交换系统的运行参数对系统热工性能的影响，研究系统的基本运行规律；(4)通过试验研究日光温室燃池-地中热交换系统的温度环境特点，并验证传热模型的正确性。通过模型(试验)研究不同布置方式的温室温度分布特点及对温室温度环境的影响；(5)分析日光温室燃池-地中热交换系统的经济性，对其做出综合评价。将燃池-地中热交换系统结合起来引入日光温室，作为日光温室的辅助加热设施，尚属首次，它的研究与使用对日光温室加热设施是一个补充，同时弥补了燃池、地中热交换系统加热效果及加热能力等方面的不足。本研究的创新点有以下几个方面：(1)首次将日光温室燃池-地中热交换系统应用于日光温室中。日光温室燃池．地中热交换系统加热属于地面(地板)加热方式，这种加热方式通过对作物的根区进行加热，与其它的加热方式如热水、热风等加热方式相比具有节能等优点，并且对作物的生长发育和产量、光合作用等都会产生积极的影响；(2)进行了日光温室燃池-地中热交换系统在冬季使用时的加热机理研究，并根据热力学与传热学基本理论建立了日光温室燃池．地中热交换系统加温的数学模型；通过对该系统在夏季降温时，考虑连续通风与间歇通风的不同工况下的降温机理研究，建立了利用地中热交换系统降温的数学模型，并进行了系统的理论分析和试验研究；(3)对建立的日光温室燃池-地中热交换系统数学模型进行数值分析及数学模拟；对建立的动态数学模型用二维不稳定导热微分方程及边界条件来描述，模型中把地中热交换通风管道模拟为无限长圆柱体，能够真实地反映空气沿管道长度，并随通风时间的不断变化的动态过程；给出了数学模型的求解方法，为模型的求解建立基础；最后利用ANSYS热分析软件进行了数学模拟分析；(4)进行了日光温室燃池-地中热交换系统的综合经济效益分析。利用费用现值和费用年值方法对其经济性进行评价，结合日光温室燃池-地中热交换系统的运行情况，对目光温室燃池-地中热交换系统初投资回收期进行了预测。本文对燃池-地中热交换加热系统进行了系统的理论分析和试验研究，得到以下主要结论：(1)分析了日光温室燃池-地中热交换系统加热机理及传热机理，建立了日光温室燃池-地中热交换系统加温数学模型；建立了利用地中热交换系统降温的数学模型。模型中把地中热交换通风管道模拟为无限长圆柱体，能够真实地反映空气沿管到长度，并随通风时间的不断变化的动态过程；给出了该数学模型的有限差分法求解方法，为模型的求解建立基础；利用ANSYS热分析软件进行了数学模拟分析，并通过试验验证了模型的正确性；(2)日光温室燃池-地中热交换系统可以有效的提高温室内的土壤温度和气温。测试结果表明，采用燃池-地中热交换系统一侧的土壤平均温度比对比侧的土壤平均温度高约2.0℃；昼夜平均气温高2.6℃，夜间平均气温高4.2℃；采用燃池-地中热交换系统土壤温度分布较均匀，沿地中热交换管道纵向方向各点最高和最低温度的温差仅为0.3℃～0.9℃；沿地中热交换管道横向方向各点最高和最低温度的温差为0.4℃～0.9℃；另外，对两侧室内湿度数据分析表明，应用日光温室燃池-地中热交换系统可以明显减少温室内相对湿度饱和时间，减少相对湿度饱和时间约2～3h；(3)燃池-地中热交换系统在夏季运行可以有效的降低温室内的气温。测试结果表明，热交换一侧与对比侧室内平均气温分别为24.7℃、25.4℃，变化不大。但在风机运行期间(测试期间风机在10：00～16：30运行)，热交换侧与对比侧室内平均气温分别为30.3℃、35.4℃，平均降温5.1℃；热交换侧最高气温为32.0℃，对比侧最高气温达38.0℃；夜间的气温较对比侧略高。试验也表明，地中热交换管道进、出口空气平均温度分别为24.7℃、19.8℃，平均降低气温4.9℃；(4)利用费用现值和费用年值方法对其经济性进行评价。分析表明，日光温室燃池-地中热交换系统的费用现值和费用年值比热风加热系统分别低30.8％和57.4％；比热水加热系统分别低27.4％和55.2％。结合日光温室燃池-地中热交换系统的运行情况，预测出该系统的初投资回收期为2.1年；(5)日光温室燃池-地中热交换系统可以充分利用太阳能及生物质能资源，节能率为31.6％，具有较好的经济效益，同时也具有较好的社会和生态效益。把燃池-地中热交换系统作为日光温室的备用加热设施，在实践中进行了应用。本文通过理论分析和试验，进行了初步的研究。研究表明，日光温室燃池-地中热交换系统较燃池、地中热交换系统从加热效果、供热能力上均有很大的改善与提高，但也存在如加热能力仍然有限、加热的控制比较困难、初投资较大、燃池部分占用一定的温室空间等问题，这些问题如能得到妥善解决，将为日光温室燃池-地中热交换系统的应用打下更加坚实的基础。更多还原

【Abstract】 Generally, many artificial heating systems which included hot-water heating system,hot-blast stove heating system, electric heating system, electricity heat pump heating systemand so on were adopted in order to maintenance production of the solar greenhouse under theextreme weather condition in winter. But application area of these heating systems waslimited due to the high cost of equipment and the operating.Fire-pit and underground heating exchange system in the greenhouse integrated fire pitheating system with underground heating exchange system, and this system can increase soiland air temperature, reduce humidity inside greenhouse during it operating. In the winterdaytime, soil temperature was increased with fire-pit releasing energy which was storedunderground through circulation of the blower and underground heating exchange pipes. Atnight, air temperature was increased and air humidity was reduced with the energy come fromthe fire-pit and part of stored underground through the blower, underground heating exchangepipes and over-ground pipes. In summer, air temperature inside greenhouse was reducedthrough circulation of the blower and underground heating exchange pipes.This paper main research includes: (1) Heat transfer mechanism of fire-pit and undergroundheating exchange system in the greenhouse was analyzed, and mathematics models of heatingtransfer were established according to the convection, the conduction and the radiation theory,and numerical value was analyzed. (2) Influence of structure parameters of fire-pit andunderground heating exchange system in the greenhouse on system thermal performance wasanalyzed according to analysis of the mathematics models. Moreover, technology andeconomy of structure parameters was optimized structure of fire-pit and underground heatingexchange system in the greenhouse on system was designed. (3) Influence of structureparameters of fire-pit and underground heating exchange system in the greenhouse on systemthermal performance was analyzed with experiment. And basic operating law of system wasresearched. (4) Temperature environment characteristic of fire-pit and underground heatingexchange system in the greenhouse was researched and heating transfer models were verified with experimental data. Furthermore temperature distribution characteristics of differentlay-form and influence on greenhouse temperature environment characteristic wereresearched with model (experiment). (5) Economy of fire-pit and underground heatingexchange system in the greenhouse was analyzed and synthesis evaluation was performed.Fire-pit and underground heating exchange system was applied in greenhouse still was forthe first time, which was an assistant heating equipment and was a supplement to heatingequipment of greenhouse. Innovation of this research main content includes: (1) Fire-pit andunderground heating exchange system was applied in greenhouse still was for the first time.And fire-pit and underground heating exchange system belongs to the floor-heating, this kindheating system heats crops-root area and has saving-energy advantage compares withhot-water heating system, hot-blast stove heating system and so on. Furthermore this kindheating system has benefiting influence on growth, output and photosynthesis of crop. (2)Heating mechanism of fire-pit and underground heating exchange system in the greenhousewas researched during winter operation. And heating mathematics model of this system wasestablished according to basic theory of thermodynamics and heat transfer. And coolingmathematics models were established according to cooling mechanism research underdifferent conditions (continuous ventilation and intermission ventilation during summercooling). And theory analysis and experiment research of this system was carried out. (3)Numerical value analysis and mathematics simulation about mathematics models of fire-pitand underground heating exchange system was carried out. And dynamic mathematics modelswas described with differential coefficient equation of two-dimensional unsteady conductionand boundary conditions, and underground heating exchange pipes were simulated to infinitycylinder, which can express actually dynamic process of air continuous movement along pipeslength and ventilation time. And calculating method of mathematics models was made out.Moreover differential coefficient equation was dispersed with finity difference method,calculating regional was meshed, and derivations were substituted with difference quetient,heat transfer differential coefficient equation was transformed into difference equation, whichwas foundation for settlement of model. And mathematics simulation analysis was carried outwith ANSYS heating analysis software and was verified with experimental data. (4) Synthesis economical benefit of fire-pit and underground heating exchange system in the greenhousewas analyzed, economy was evaluated with present value and annual value of expenditure,and returning time of primary investment was forecasted to fire-pit and underground heatingexchange system in the greenhouse through it operating condition.Main conclusion was made with systemic theory analysis and experiment research on fire-pit and underground heating exchange system in the greenhouse. (1) Heat transfer mechanismwas analyzed and mathematics models of heating transfer were established of fire- pit andunderground heating exchange system in the greenhouse. And cooling mathematics modelswere established, and underground heating exchange pipes were simulated to infinity cylinder,which can express actually dynamic process of air continuous movement along pipe lengthand ventilation time. And difference calculating method of mathematics models was made out,which was foundation for calculating of model. Moreover mathematics simulation analysiswas carried out with ANSYS/THERMAL and was verified with experimental data. (2) Soiland air temperature inside greenhouse was increased greatly with fire-pit and undergroundheating exchange system in the greenhouse. Testing results indicated that soil averagetemperature, day and night average air temperature, nighttime average air temperature of areawith fire-pit and underground heating exchange system was higher respectively 2.0℃, 2.6℃,4.2℃than contrast area. And soil temperature distributing was uniformity with this system.So temperature difference from maximal to minimum was respectively 0.3℃～0.9℃, 0.4℃～0.9℃along vertical section and cross section of underground heating exchange pipes.Furthermore both side humidity data which was analyzed indicated that saturation time ofrelative humidity was shortened greatly with adopted fire-pit and underground heatingexchange system in the greenhouse, which was shortened 2～3h. (3) Air temperature insidegreenhouse was reduced greatly with fire-pit and underground heating exchange system insummer. Testing results indicated that average air temperature was respectively 24.7℃, 25.4℃both heating exchanged area and contrast area, which temperature difference was small. Butaverage air temperature was respectively 30.3℃, 35.4℃both heating exchanged area andcontrast area during blower operating (operation time of blower was from 10:00 to 16:30during testing), and average air temperature was reduced 5.1℃. maximal air temperature ofheating exchanged area was 32.0℃, and maximal air temperature of contrast area was 38.0℃. But at night air temperature was higher in heating exchanged area than contrast area.Furthermore experiment results indicated that air average temperature was respectively 24.7℃, 19.8℃at import and exit of underground heating-exchanged pipes, and average airtemperature was reduced into 4.9℃. (4) Economy was evaluated with method of present valueand annual value of expenditure. Analysis indicated that present value and annual value ofexpenditure of fire-pit and underground heating exchange system in the greenhouse was lowerrespectively 30.8%,57.4% than hot-blast stove heating system, and lower respectively 27.4%,55.2% than hot-water heating system. And returning time of primary investment wasforecasted to 2.1 years according to operating condition of fire pit-underground heatingexchange system in the greenhouse. (5) Fire-pit and underground heating exchange system inthe greenhouse was able to utilize sufficiently solar energy and biomass energy, and savingenergy rate was 31.6%. So it has healthy economical, social and ecological benefit.Fire-pit and underground heating exchange system was used as assistant heatingequipment in the greenhouse. In this paper, primary research was carried with theory analysisand experimental data. And research results indicated that heating effect and capability offire-pit and underground heating exchange system has more improvement than fire pit heatingsystem and underground heating-exchanged system. But this heating system have manydisadvantage, such as heating capability was still limited, heating control was difficult,primary investment was large, fire-pit area possess part of space inside greenhouse and so on.If these problems were solved, application foreground of fire-pit and underground heatingexchange system was wide.更多还原