为了降低冷藏陈列柜运行能耗,将自然冷源引入具有储能装置的冷藏陈列柜,对搭建的自然冷源食品冷藏陈列柜系统的5种工作模式(制冷机组单独供冷、制冷机组供冷+蓄冷、蓄冷罐供冷、自然冷源供冷和自然冷源供冷+蓄冷)进行了试验研究.研究结果表明:在5种工作模式下,均能使柜内温度维持在-1～7?℃之间,符合冷藏陈列柜食品冷藏要求.在制冷机组供冷+蓄冷模式下,以2.34?m3/h的乙二醇溶液对蓄冷罐蓄冷12?h后,蓄冷罐能够储存121400?kJ的冷量,该冷量可使柜内温度在9?h内维持在-1～7?℃之间.当室外温度低于-4.5?℃时,可运行自然冷源单独供冷模式.当室外温度小于?-8?℃时,利用自然冷源对陈列柜供冷的同时可以对蓄冷罐蓄冷.运行蓄冷罐单独供冷模式和自然冷源单独供冷模式,能够使系统的能耗分别降低68.45％和55.42％.

This work focuses on the heat transfer and flow characteristics with the different placement of the multi-deck display cabinet and tries to optimize the placement position of refrigerated display cabinet. First, the temperature distribution in a refrigerated display cabinet was experimentally investigated. The result showed that the food temperature in front is 3.6–4.8°C higher than back row of the same layer, and temperature fluctuation of 0.3–0.7°C less than the back row. Then, a three-dimensional numerical model of the display cabinet was established, and the k–ε model is employed to compare and analyze the heat transfer and air curtain characteristics. The results show that the placement methods have great influence on the performance of the display cabinet. The face-to-back placement method can acquire a better food refrigeration performance, and the food temperature of the face-to-back placement method is 0.3–0.5°C lower than that of the face-to-face placement method.

In this study, an airfoil structure was added in front of the display cabinet shelf to optimize the performance of a vertical open-type refrigerated display cabinet. The influence of the airfoil structure on the performance of a vertical open refrigerated display cabinet was studied by testing the performance of the refrigerated display cabinet after addition of the airfoil structure. The test results show that under an ambient temperature of 25 ℃and relative humidity of 60 %, the evaporation temperature of the refrigeration system increased from ?6.3 ℃ to ?4.5 ℃ after installation of the airfoil structure. The average temperature fluctuation of supply and return air varied from 0.6?4.4 ℃, 10.3?12.0 ℃ to 1.8?3.0 ℃ and 6.0?7.4 ℃. The supply air velocity was essentially the same, and the return air velocity decreased by 10.2%–16.9%. The thermal permeability coefficient in the display cases decreased by 46%–48%. The maximum average temperature difference of food in different layers of the cabinet decreased by 31%, and the maximum average temperature difference of food inside and outside decreased by 46.2%. The total heat emission of the showcase decreased from 82.33 kW?h/24 h to 66.49 kW?h/24 h. The total energy consumption of the system decreased from 42.91 kW?h/24 h to 33.61 kW?h/24 h. The results show that the refrigerating system performance, air curtain performance, temperature uniformity, and energy utilization ratio of the open display cabinet can be improved by adding an airfoil structure at the front end of the shelf.

The load of the showcase is a nonlinear and unstable time series data, and the traditional forecasting method is not applicable. Deep learning algorithms are introduced to predict the load of the showcase. Based on the CEEMD–IPSO–LSTM combination algorithm, this paper builds a refrigerated display cabinet load forecasting model. Compared with the forecast results of other models, it finally proves that the CEEMD–IPSO–LSTM model has the highest load forecasting accuracy, and the model’s determination coefficient is 0.9105, which is obviously excellent. Compared with other models, the model constructed in this paper can predict the load of showcases, which can provide a reference for energy saving and consumption reduction of display cabinet.

为了挖掘冷藏陈列柜运行数据的有效信息,实现冷藏陈列柜制冷负荷的预测,针对运行数据存在时间序列性和非线性等特性,提出了基于深度学习的LSTM神经网络模型.将日期信息、蒸发器进出口温度、压力、焓值、流量数据按照时间步长划分为训练集与测试集,模型导入后经过训练证明最优方案:模型网络层数为4、训练次数为200,将预测负荷数据与实际负荷进行比对,发现预测模型绝对百分比误差仅为1.98％,具备较好的预测性能.