【作者】 曹楠；

【导师】 林聪；

【作者基本信息】 中国农业大学 ， 农业生物环境与能源工程， 2004， 硕士

【摘要】 连栋温室中，辐射、传导、对流、水分蒸发、作物蒸腾以及冷凝结露引起的湿热交换等蓄热、放热过程的耦合以及外界寒冷气象参数的动态变化时刻影响着温室的内部环境。覆盖材料的透光性能、保温性能、强度、耐候性、抗老化性、防雾滴性等是评价温室用农膜的重要方面。 现有温室覆盖材料主要有玻璃，聚碳酸酯板，聚氯乙烯、聚乙烯和乙烯—醋酸乙烯薄膜，但各自均存在缺点，研究开发新型覆盖材料具有重要意义。聚对苯二甲酸乙二醇酯(PET)是一种新型聚合材料，物理性能优异，目前在化工、包装、医疗等行业有着广泛的应用，本文将主要研究改性后的PETP薄膜作为农业覆盖材料的光热性能。 试验采用稳态热箱法在室内条件下，测试了新型覆盖材料PETP薄膜和其它几种农业常用覆盖材料的热工性能。通过分析所测各种材料的传热系数(K)的大小，研究发现0.1mm厚PETP薄膜保温性能介于8mm厚PC中空板和0.15mm厚PVC薄膜之间，且随厚度增加，保温性能有所提高。同时测试了各覆盖材料的全光辐射透过率并进行分析比较，研究发现PETP薄膜在冬季夜间温室内热辐射集中的5-25μm波段辐射的透过率远小于PE和PVC薄膜。热辐射透过率在一定程度上反映出材料的保温性能，从另一侧面证明了各种覆盖材料传热性能热箱法的实测结果。另外在太阳辐射范围，PETP薄膜表现出优异的透射性能，与温室覆盖材料理想透射曲线基本吻合。更多还原

【Abstract】 In multi-span greenhouses, the coupling of heat storage and release courses caused by radiation, conduction, convection, wet evaporation, crop rising and condensation and the dynamic change of the outdoor cold weather parameters affect the indoor environment momently. Such aspects of covering materials as light permeation performance, heat preservation performance, endurable performance, anti-aging performance, dew drips resistance performance and intensity are the important indexes to appraise the qualities of the covering films for greenhouses.The main covering materials in existence for greenhouses are glasses, PC hollow board, PVC, PE and EVA plastic films. Each of them has shortcomings. It badly demands researching and developing new agricultural covering materials. Polyethylene terephthalate (PET) is a new type of polymeric plastic materials. With the excellent physics performance, PET has been widely applied into many industries such as chemical industry, packaging industry and medical treatment trade. The paper mainly researches on the photothermic property of PETP film (changed by PET materials) utilizing as agricultural covering materials.Under the indoor steady state, the thermal properties of new type PETP film and several kinds of common covering materials have been measured by the method of one-dimensioned thermal insulated box. After analyzing the thermal transmittance (K) of different materials, the following conclusion is drawn that the heat preservation property of PETP film with 0.lmm thickness is between those of 8mm thick hollow PC hollow board and 0.15mm thick PVC film. Moreover, the heat preservation capability of PETP film will augment with the increase of thickness. The whole spectrums of PETP film and other covering materials have been measured simultaneously. After comparing the spectrums, it is found that in winter during 5~25um, the main radiation extent of inside heat radiation, the heat transmitting rate of PETP film is further less than those of the others. Transmitting rate can reflects the heat preservation performance in a degree. So that can prove, from another aspect, the experimental results of the heat transfer performances of various covering materials. Moreover, PETP film has excellent property of transmitting solar radiation, the chart of which basically tallies with the ideal transmitting chart of covering materials for greenhouses.更多还原