中低温工况下风机盘管性能的实验研究

发布时间：2018-04-24 01:36

本文选题：中低温工况 + 风机盘管　；参考：《天津商业大学》2016年硕士论文

【摘要】：食品保鲜行业的发展使高温食品的冷藏环境得到广泛应用,一般来说,各种农产品(瓜、果、蔬菜等)适宜的储存环境要求在8-20℃。优化和提高冷藏环境室的设备性能,对高温冷藏环境室的节能运行意义重大。在实际高温冷藏室中,人员频繁作业,直接将制冷剂的末端设备(如冷风机)与人员操作空间相连接,制冷剂充注量大,势必对人员安全性造成威胁。如果采用载冷剂系统则可以克服上述缺点,减少制冷剂充注量大并避免安全隐患。风机盘管是空调系统中常见的载冷剂换热设备,具有价格低廉等优势,如果将风机盘管应用于高温冷藏室,势必会拓展风机盘管的使用范围,同时也解决了高温冷藏室末端设备短缺问题。与空调系统不同,在高温冷藏环境室中应用的风机盘管工作在偏离风机盘管标准工况的中低温工况下。因此,本文将重点研究中低温工况下风机盘管的供冷能力,传热性能以及析湿系数的变化情况,开展高温冷藏环境室采用风机盘管的理论分析和实验研究。通过研究干湿工况下风机盘管对室内空气的热湿处理过程,建立中低温工况下风机盘管变工况的数学模型,搭建中低温工况下风机盘管系统实验台,通过改变载冷剂进口温度、载冷剂流量和环境室温度,对风机盘管的供冷能力、焓效率、换热温差以及析湿系数的变化情况进行研究,掌握风机盘管在中低温工况下运行时的性能。研究结果表明：风机盘管的供冷量随载冷剂进口温度的变化规律基本上呈线性关系,与标准工况相比,室温18℃供冷量约为标准工况的47.8%-8.7%；室温15℃供冷量约为标准工况的41.2%-15.9%；室温12℃供冷量约为标准工况的32.8%-11.9%；维持环境室温度、载冷剂流量以及风量不变时,载冷剂进口温度每上升1℃,供冷量约降低5%；维持载冷剂进口温度,流量以及风量不变时,环境室温度为18℃、15℃、12℃,室温每降低3℃时,供冷量依次降低12.9%、9.41%,说明室温较高的情况下,对供冷量的影响更大；风机盘管的焓效率与载冷剂进出口温度,进出口风温无关,只与载冷剂流速以及风量有关,用焓效率法计算供冷量与实验值相差在10%之内,计算结果精度很高,推荐推广使用；中低温环境室冷风比需在2.2-3.5之间,宜选用的载冷剂进口温度推荐值为：环境室温度为12℃时,进口载冷剂温度为4℃及以下；环境室温度为15℃时,载冷剂进口温度应选择在4℃-7℃；环境室温度为18℃时,载冷剂进口温度应选择在5℃-9℃总体来看,载冷剂进口温度与流量对风机盘管影响很大,为了工程设计选型方便,根据实验测试结果,拟合出偏离标准工况下的供冷量、进出口温差、传热温差、全冷量焓效率、显冷量焓效率、析湿系数等的性能回归方程的适用公式：供冷量：载冷剂进出口温差：传热温差：△tm=0.0511t2.3649twl-1.2496qv-0.1849,相关系数为0.90以上全冷量焓效率：εh=1.632Vy0.5191qm0.6114、显冷量焓效率：εs=1.208Vy0.135qm0.5951,相关系数在0.95以上析湿系数：ξ=0.7450t-0.3712twl0.5913qv0.1160,相关系数在0.85以上。
[Abstract]:The development of food preservation industry makes the cold storage environment of high temperature food widely used. Generally, the suitable storage environment of various agricultural products (melon, fruit, vegetable and so on) is required at 8-20. The optimization and improvement of the equipment performance of the refrigerated environment room is of great significance to the energy saving operation of the high temperature refrigerated environment room. The end equipment of the refrigerant (such as the cold fan) is connected directly with the operating space of the personnel, and the refrigerant is filled with large amount, which will threaten the safety of the personnel. If the refrigerant system is used, the disadvantages can be overcome, the refrigerant charge is greatly reduced and the hidden danger is avoided. The fan coil is the common refrigerant exchange in the air conditioning system. The heat equipment has the advantages of low price and so on. If the fan coil is applied to the high temperature cold storage room, it will expand the use range of the fan coil and solve the problem of the terminal equipment shortage in the high temperature cold storage room. The fan coil work in the high temperature refrigerated environment room is different from the standard condition of the fan coil unit. Under the condition of medium and low temperature, this paper will focus on the cooling capacity, heat transfer performance and the change of the humidity coefficient of the fan coil in the low temperature condition, and carry out the theoretical analysis and experimental study of the fan coil in the high temperature refrigerated environment room. In the middle and low temperature conditions, the mathematical model of the fan coil unit is set up, and the experimental platform of the fan coil system is set up in the middle and low temperature conditions. By changing the inlet temperature of the refrigerant, the flow of the refrigerant and the temperature of the environment, the cooling capacity of the fan coil, the enthalpy efficiency, the heat transfer temperature difference and the change of the number of the dehumidification system are studied. The results show that the cooling capacity of the fan coil is basically linear with the changing law of the inlet temperature of the refrigerant. Compared with the standard condition, the cooling capacity at room temperature is about 47.8%-8.7% of the standard working condition at 18 C, the cooling capacity at room temperature is about 41.2%-15.9% of the standard condition, and the cooling capacity at room temperature is about 12. For 32.8%-11.9% of standard operating conditions, when the temperature of the environment, the flow of refrigerant and the air volume are constant, the inlet temperature of the refrigerant is increased by 1 degrees centigrade, and the cooling capacity is reduced by about 5%. When the inlet temperature of the refrigerant, the flow and the volume of the air are kept constant, the temperature of the environment room is 18, 15, 12, and the room temperature decreases by 3 degrees centigrade, and the cooling capacity is reduced by 12.9%, 9.41% in turn. The enthalpy efficiency of the fan coil is not related to the inlet and exit temperature of the refrigerant and the inlet and outlet temperature. The enthalpy efficiency of the fan coil is only related to the flow rate and the air volume of the refrigerant. The enthalpy efficiency method is used to calculate the difference between the cooling capacity and the experimental value of 10%, and the precision of the result is very high and the low temperature environment is recommended. The recommended value of the inlet temperature of the refrigerant for the room cold air is compared with the 2.2-3.5. The inlet temperature of the imported refrigerant is 4 centigrade when the environment room temperature is 12 C, and the inlet temperature of the refrigerant should be selected at 4 C at the temperature of 15 C at the temperature of 4 C, and the inlet temperature of the refrigerant should be selected at 5 C -9 C when the environment room temperature is 18. To see, the inlet temperature and flow rate of the refrigerant have great influence on the fan coil. For the convenience of the design of the engineering design, according to the experimental test results, the applicable formula for the performance regression equation of the cooling capacity, the temperature difference of the import and export, the heat transfer temperature, the total cooling enthalpy efficiency, the sensible cooling enthalpy efficiency, the number of dehumidification system, and so on, is fitted out. The temperature difference of the inlet and outlet of the refrigerant: the heat transfer temperature difference: Delta tm=0.0511t2.3649twl-1.2496qv-0.1849, the correlation coefficient is above 0.90 total cooling enthalpy efficiency: epsilon h=1.632Vy0.5191qm0.6114, the apparent cooling enthalpy efficiency: epsilon s=1.208Vy0.135qm0.5951, the correlation coefficient is above 0.95, the coefficient of wetting coefficient is = 0.7450t-0.3712twl0.5913qv0.1160, and the correlation coefficient is above 0.85.

【学位授予单位】：天津商业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB657.2

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