基于毛细管换热器的日光温室低温供暖系统设计  

Design of low temperature heating system in solar greenhouse using capillary tube mat exchanger

作　　者：丁小明[1,2] 何芬[1,2] 段静[1,2] 连青龙[1,2] 张秋生[1,2] 

机构地区：[1]农业部规划设计研究院设施农业研究所,北京100125 [2]农业部农业设施结构工程重点实验室,北京100125

出　　处：《农业工程学报》2013年第19期178-184,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：公益性行业(农业)科研专项(201203002);北京市科技计划(Z111105055111006)

摘　　要：为将毛细管换热器应用于日光温室中,该文试验测试了毛细管换热器的热工性能和流动阻力,得到毛细管换热器在0.0306、0.0222和0.0139 kg/s流量下散热量与过余温度(20~50℃范围内)的关系曲线以及相应阻力和流量的变化关系曲线。在低于40℃的低温热水供暖状态时,在25~30℃的过余温度下毛细管换热器垂直放置时可提供258~323 W/m^2的散热量,而水平放置时散热量达到307~381 W/m^2。在此基础上,设计了一套采用生物质固体成型燃料供热的基于毛细管换热器的日光温室低温供暖系统,试验温室和对照温室建筑面积均为518.5 m^2。测试结果表明,采用合理的供暖方案,在每天燃烧秸秆固体成型燃料125 kg能保证试验温室夜间平均冠层气温10℃以上,-15 cm土壤温度15℃以上,与对照温室相比,夜间平均气温、最低气温和-15 cm土壤温度分别提高了9.0、6.5和5.7℃。Solanaceous fruit vegetables are able to be planted in a solar greenhouse without a heating system during winter in northern China. But low temperatures under 8 ℃ often happen at night in a solar greenhouse. So a heating system in a solar greenhouse is a crucial technology for agricultural fresh produce such as vegetables in winter in order to improve the inner environment. A new heating technique using a capillary tube mat exchanger was introduced to a solar greenhouse. Thermal characteristics and property of flow resistance were tested under 0.0306 kg/s, 0.0222 kg/s and 0.0139kg/s water flow rates and 20-50℃ excess temperature in a laboratory. The diameter and wall thickness of the capillary tube was 4 mm and 1 ram. The length, width, and distance between neighboring capillary tubes were 2800 mm, 600 mm, and 20 mm. Function curves of heat flux and local resistance under different water flux were obtained. The influence of water flux could be ignored, but set position had a great influence on the results. The heat fluxes were 258-323 W/m2 and 307-381 W/m2 when sample capillary tube mat exchangers were set with vertical position and horizontal position under an excess temperature of 25-30℃. In order to test the feasibility of the capillary tube mat exchangers in a solar greenhouse, a low water temperature heating system using capillary tube mat exchangers was designed for a solar greenhouse with a 518.5m2 covered area seated in Beijing Changping district. 120 m2 capillary tube mat exchangers were installed along the back wall and side wail in the solar greenhouse. A biomass boiler supplied the 60℃ heat water. Low 40℃ water was supplied to the capillary tube mat exchangers using a water mixing valve. Contrast tests were conducted between two same structure solar greenhouses in winter during the year 2012 through 2013, during which one solar greenhouse with a heating system and the other without were monitored. Soil temperature at the 15cm depth and canopy temperature were measured every 10 minutes during

关 键 词：温室 毛细管 换热器 日光温室 热工性能 流动阻力 

分 类 号：S625.4[农业科学—园艺学]