共查询到20条相似文献，搜索用时 62 毫秒
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根据稻谷烘干的工艺要求，以泰州市某家庭农场的空气源热泵粮食烘干机为例，对基于物联网的空气源热泵热风机组在不同环境温度、匹配不同烘干机工况下的性能进行试验研究，通过采集干燥机热风温度、风量、耗电量等数据，计算热泵系统制热量、性能系数（coefficient of performance,COP）、除湿能耗比(specific moisture extraction rate,SMER)以及烘干成本等数据，对热泵系统的实际性能进行分析。结果表明：空气源热泵系统的性能受环境平均温度的显著影响，随环境温度升高，热泵的制热量逐步减少，COP逐渐增加、SMER增大；但当环境温度低于9℃时，热泵出风温度达不到设定值，COP和SMER均低于均值；当环境温度高于9℃时，系统表现出良好性能。 相似文献
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以太阳能-空气源热泵牧草干燥系统为研究对象，通过系统不同工作模式的温升、恒温制热试验及带载试验，分析了温升速率、单位温升能耗、COP及除湿效率。研究结果表明：联合制热模式与太阳能单独制热相比，单位温升耗电量降低了86.2%,温升速率提高了99～112倍。联合制热模式与热泵单独制热试验相比，在温升过程中温升速率降低了7.7%～17.6%,单位温升耗电量降低8.0%;在恒温制热过程中，前者COP比后者提高了6.5%～11.1%,耗电量降低了5.8%～10.7%;在升温制热过程中前者COP比后者提高了6.0%～10.4%,耗电量降低了6.6%～11.1%。联合干燥模式比热泵单独干燥模式的SMER值高19.8%～36.2%。 相似文献
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热泵除湿法在农副产品干燥中的应用分析 总被引：1，自引：0，他引：1
通过对热泵除湿干燥工艺技术特征,优越性及存在问题与解决途径的讨论和分析,认为;如何降低电耗,降低成本是其于农副产品干燥的关键,并认为本身价值较高或加工 有高附加值的农副产品应用热泵除湿法干燥有发展前景。 相似文献
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柴油发电机驱动的热泵干燥系统开发与优化 总被引：1，自引：1，他引：0
设计了柴油发电机驱动的移动式热泵干燥系统,该系统由蒸汽压缩式热泵(热泵工质为R134a)提供热量,以卧式多室流化床为干燥室。在风道中设置换热器回收柴油机冷却水和烟气余热,以提高系统一次能源利用率。针对该系统建立了流化床、热泵、柴油发电机组耦合为一体的综合数学模型。数学模型计算结果表明:干燥室入口空气温度在60～90℃时,干燥系统的除湿能耗比先升后降,在70℃附近存在一个最大值。样机实验表明:设备在设计工况下运行时,平均热泵性能系数为4.66,一次能源利用率为1.09,除湿能耗比可达3.08 kg/(kW·h),模型计算与实验结果吻合良好,采用该装置进行谷物干燥节能效果明显。 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性，认为在缺水不可避免的情况下，对供水进行优化调度可以减小缺水带来的损失，产生较好的减灾效益，特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性，提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献