太阳能吸附式果蔬预冷库技术研究
发布时间：2018-12-09 20:09
【摘要】：随着经济的发展,环境保护和能源危机已成为世界关注的焦点,因此开发利用可再生能源具有非常重要的现实意义。我国是农产品生产、消费大国,但冷藏运输上损耗也很严重。果蔬预冷是冷链中的重要环节,将新鲜的果蔬在第一时间预冷可以最大程度上保证其品质。由于传统的预冷库都需要消耗电能,因而制约了其在田间地头上的应用。 目前我国大多数果蔬在采摘后都不经预冷而直接运输或销售,因此果蔬的品质受到了严重的影响。如果以太阳能作为果蔬产地预冷库的能源动力,则是既能提高果蔬贮藏品质,又可以采用环保能源的完美结合。 文中综合国内外对太阳能吸附式制冷技术的研究现状,以活性炭-甲醇为工质对,分别采用真空集热管—水冷集热吸附床和平板—自然冷却集热吸附床进行研究,对间歇和连续制冷循环方式进行了数值计算和相关实验。 根据相关计算搭建了实验台,设计了真空管集热吸附床、平板集热吸附床及配套冷凝器、蒸发器和节流装置。并对吸附床传热传质、装置的便捷性和牢固性等方面提出了一些改进。 通过对集热吸附床的数值计算与分析,得出吸附床内温度、吸附剂的吸附速率随时间的变化关系。在日太阳最大辐射强度为790W/m2且其强度按正弦变化的条件下,计算出平板型吸附式制冷系统制冷系数COPref为0.594,真空管系统的COPref为0.517,脱附结束时平板系统内残留甲醇占全部甲醇的百分比为6.3%,真空管为3.8%。 利用实验装置进行了三组实验：其一是平板系统自然冷却间歇式制冷,其二是真空管系统水冷间歇式制冷,其三是真空管系统水冷连续式制冷。实验测出在蒸发温度为0℃,冷凝温度为40℃的工况下,平板系统间歇式制冷的太阳能制冷系数COP值为0.109～0.118；真空管系统间歇式制冷的太阳能制冷系数COP值为0.095～0.102；真空管系统连续式制冷的太阳能制冷系数COP值为0.105～0.110。将吸附床温度的实验结果和数值计算结果进行了比较,验证了所建立模型的准确性。 分析了太阳能吸附式预冷库技术性能,客观地指出存在的问题,并对以后工作提出了建议。
[Abstract]:With the development of economy, environmental protection and energy crisis have become the focus of the world's attention, so the development and utilization of renewable energy has a very important practical significance. Our country is agricultural product production, consumption big country, but refrigerated transportation is also very serious. Pre-cooling of fruits and vegetables is an important part of cold chain, and the quality of fresh fruits and vegetables can be guaranteed to the greatest extent by pre-cooling fresh fruits and vegetables in the first time. The application of precooled storage in the field is restricted because of the need to consume electric energy. At present, most fruits and vegetables in our country are transported or sold directly without pre-cooling after picking, so the quality of fruits and vegetables is seriously affected. If solar energy is used as the energy power of fruit and vegetable production area, it can not only improve the storage quality of fruits and vegetables, but also adopt the perfect combination of environmental protection energy. In this paper, the research status of solar energy adsorption refrigeration technology at home and abroad is summarized. The vacuum collector tube water cooled adsorption bed and flat plate natural cooling collector adsorption bed are used to study the adsorption bed with activated carbon methanol as working medium. The batch and continuous refrigeration cycles were numerically calculated and related experiments were carried out. According to the relevant calculation, the experiment bench was built, and the vacuum tube heat collecting adsorption bed, flat plate heat collecting adsorption bed and matching condenser, evaporator and throttling device were designed. Some improvements on heat and mass transfer of adsorption bed, convenience and fastness of the device are put forward. Through the numerical calculation and analysis of the adsorption bed, the relationship between the temperature in the adsorption bed and the adsorption rate of the adsorbent with time is obtained. Under the condition that the maximum solar radiation intensity is 790W/m2 and its intensity varies according to sinusoidal, the refrigeration coefficient COPref of plate adsorption refrigeration system is 0.594, and the COPref of vacuum tube system is 0.517. At the end of desorption, the percentage of residual methanol in the plate system was 6.3% and the vacuum tube was 3.8%. Three groups of experiments were carried out by using the experimental device: one is the natural cooling intermittent refrigeration of the flat panel system, the other is the water-cooled intermittent refrigeration of the vacuum tube system, and the third is the water-cooled continuous refrigeration of the vacuum tube system. Under the condition of evaporation temperature 0 鈩，
本文编号：2369959
[Abstract]:With the development of economy, environmental protection and energy crisis have become the focus of the world's attention, so the development and utilization of renewable energy has a very important practical significance. Our country is agricultural product production, consumption big country, but refrigerated transportation is also very serious. Pre-cooling of fruits and vegetables is an important part of cold chain, and the quality of fresh fruits and vegetables can be guaranteed to the greatest extent by pre-cooling fresh fruits and vegetables in the first time. The application of precooled storage in the field is restricted because of the need to consume electric energy. At present, most fruits and vegetables in our country are transported or sold directly without pre-cooling after picking, so the quality of fruits and vegetables is seriously affected. If solar energy is used as the energy power of fruit and vegetable production area, it can not only improve the storage quality of fruits and vegetables, but also adopt the perfect combination of environmental protection energy. In this paper, the research status of solar energy adsorption refrigeration technology at home and abroad is summarized. The vacuum collector tube water cooled adsorption bed and flat plate natural cooling collector adsorption bed are used to study the adsorption bed with activated carbon methanol as working medium. The batch and continuous refrigeration cycles were numerically calculated and related experiments were carried out. According to the relevant calculation, the experiment bench was built, and the vacuum tube heat collecting adsorption bed, flat plate heat collecting adsorption bed and matching condenser, evaporator and throttling device were designed. Some improvements on heat and mass transfer of adsorption bed, convenience and fastness of the device are put forward. Through the numerical calculation and analysis of the adsorption bed, the relationship between the temperature in the adsorption bed and the adsorption rate of the adsorbent with time is obtained. Under the condition that the maximum solar radiation intensity is 790W/m2 and its intensity varies according to sinusoidal, the refrigeration coefficient COPref of plate adsorption refrigeration system is 0.594, and the COPref of vacuum tube system is 0.517. At the end of desorption, the percentage of residual methanol in the plate system was 6.3% and the vacuum tube was 3.8%. Three groups of experiments were carried out by using the experimental device: one is the natural cooling intermittent refrigeration of the flat panel system, the other is the water-cooled intermittent refrigeration of the vacuum tube system, and the third is the water-cooled continuous refrigeration of the vacuum tube system. Under the condition of evaporation temperature 0 鈩，
本文编号：2369959
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