基于低品位热源再生溶液除湿方式的空调系统研究

发布时间：2018-01-05 23:28

本文关键词：基于低品位热源再生溶液除湿方式的空调系统研究　出处：《江苏大学》2014年博士论文　论文类型：学位论文

【摘要】：暖通空调系统的舒适性和能耗问题日益受到重视,对传统冷冻除湿空调系统提出了新的挑战。传统空调系统为了除湿需要将空气处理到露点状态,既增加了压缩机的耗功,又降低了空气的舒适度,不能完全适应当今社会对空调系统的要求。目前以湿度控制为突破口,国内外研究者提出了一些新的空气调节方式和系统。本文从传质动力角度利用理论和实验手段研究了LiCl溶液除湿和再生过程。试验测试了传统冷冻除湿空调机组的变工况运行特性。在上述理论分析和试验结果的基础上,设计了低品位热源再生的小型溶液除湿复合空调系统,并分析了系统能耗情况。从理论角度,基于溶液除湿过程传质动力的分析,依据LiCl溶液和湿空气的物性参数关系,编程计算了等温除湿过程的平衡曲线。在假设水蒸气凝结潜热全部进入溶液中的条件下,计算了溶液温升平衡曲线。以溶液和空气进口温度为25℃、30℃和35℃为例,将温升平衡曲线和与之对应的等温除湿平衡曲线比较发现,两者差距随溶液浓度降低而减小,而且进口温度越高,两者差距越明显。开展了LiCl溶液除湿试验研究。试验结果表明：凝结热主要引起溶液温升；除湿量随空气流量增加而增加,并非随溶液流量单调增加；当满足空气和溶液充分接触条件时,除湿效率随空气流量增加而降低；除湿效率随溶液流量的变化类似于除湿量随溶液流量的变化特点。通过两种高度的填料的除湿性能比较发现,除湿量随填料高度增加而增大,但总容积传质系数减小。说明除湿过程同传热过程类似,存在入口段效应。 LiCl溶液再生试验结果表明,再生效果随溶液质量浓度增加而下降。再生量随溶液进口温度上升而增加,当溶液进口温度低于50℃时,再生效果较差。为进行复合空调系统热泵机组变工况条件下的能效分析,试验研究了传统冷冻除湿空调机组变工况运行性能并获得机组能效比随蒸发温度和冷凝温度变化的修正系数。试验表明,室内环境参数对制冷量和除湿量有明显的影响。对于一定温湿度环境,单位除湿量耗功与循环风量呈二次曲线关系,具有极小值。湿度越大,该极值越小,而且向大风量偏移。基于热湿独立控制原理和上述理论分析和试验研究结果,提出了二次回风两级溶液除湿方案,设计了低品位热源再生的小型溶液除湿复合空调系统。复合空调系统以保证出风参数优先,同时满足溶液再生温度和最大需热量要求。为此,设计使用了两台小热泵机组提供17℃高温冷水用于冷却空气和溶液,同时通过调节冷冻水流量分配实现系统综合能效比的最大化。最后,以上海地区一三层别墅为例,分别建立了独立风冷热泵空调系统、地源热泵空调系统、复合空调系统的能耗分析模型。以夏季7、8两月最大负荷作为机组选择依据,以除湿率基本相等为基础,分析比较了三类空调系统在运行期间的送风参数、除湿性能、机组能耗等。结果表明,复合空调系统以小温差大风量形式送风,在保证出风温度的条件下,出风相对湿度降低,可以改善室内舒适度。在溶液除湿部分再生器溶液进口温度按照52℃,换热器效能按0.7设计时,复合空调系统节能优势并不明显。当换热器效能提高至0.8时,综合能效比平均提高0.22,有一定的节能优势。
[Abstract]:Comfort and energy consumption of HVAC system has received increasing attention, a new challenge to the traditional refrigeration dehumidification air conditioning system. The traditional air conditioning system for dehumidifying air treatment will need to dew point state, which not only increase the compressor power consumption and reduces the air comfort, can not fully meet the requirements of today's society on the air conditioning system. At present, the humidity control as a breakthrough, the domestic and foreign researchers put forward some new ways and the air conditioning system.
This paper from the perspective of dynamic mass transfer by theoretical and experimental methods to study the LiCl solution dehumidification and regeneration process. Test the changing working conditions of traditional refrigeration dehumidification air conditioning unit. Based on the theoretical analysis and experimental results, the design of small liquid desiccant air-conditioning system of regeneration of low grade heat source, and analyzes the system energy consumption.
From the angle of theory, analysis of dynamic transfer solution dehumidification process based on LiCl, according to the relationship between the solution and the physical parameters of wet air, programming to calculate the equilibrium curve of isothermal dehumidification process. Under the assumption that the water vapor condensation all go into solution under the condition of ascending temperature calculation. The equilibrium curve solution in solution and air inlet temperature 25 degrees, 30 degrees and 35 degrees as an example, the temperature rise of the equilibrium curve and the corresponding isothermal dehumidification equilibrium curve comparison, the difference decreases with the solution concentration decreased, and the inlet temperature is higher, the gap is more obvious.
Experiment was conducted to study the liquid desiccant LiCl. The experimental results show that the condensation heat is mainly caused by the solution temperature rise; dehumidification capacity increases with the increase of air flow rate increased, with the increase of the flow rate of solution is not monotone; when the air and solution of contact conditions, dehumidification efficiency decreases with the increase of air flow rate; dehumidification efficiency varies with the flow rate of solution is similar to the the dehumidification changes with the characteristics of solution flow. Through the dehumidifying performance of two kinds of the packing height comparison found that the dehumidification with the filling height increases, but the total volumetric mass transfer coefficient decreases. Simultaneous thermal process of dehumidification process is similar, there are entrance effect.
The results of LiCl solution regeneration test showed that the regeneration effect decreased with the increase of solution concentration. The amount of regeneration increased with the increase of inlet temperature. When the inlet temperature of solution was below 50 C, the regeneration effect was poor.
Analysis of heat pump air-conditioning system under the condition of energy efficiency, testing the traditional refrigeration dehumidification air conditioning unit operation performance and energy efficiency ratio correction coefficient with the variation of evaporation temperature and condensation temperature. The results show that the indoor environment parameters have obvious effects on the refrigerating and dehumidifying capacity for temperature and humidity. The environment, power consumption is two units of the dehumidification curve relation with circulating air, has the minimal value. The extreme humidity is bigger, smaller, and large volume to offset.
Heat and humidity independent control principle and the theoretical analysis and experimental results based on the proposed two return two solution dehumidification scheme, design of small liquid desiccant air conditioning system of recycled composite low grade heat source. The air-conditioning system to ensure air parameters satisfy the requirements of priority, and the maximum heat solution regeneration temperature. Therefore, design the use of two sets of small heat pump unit provides 17 degrees high temperature cold water for cooling air and solution, at the same time by maximizing the adjustment of chilled water flow allocation system of comprehensive energy efficiency.
Finally, the 13 storey villa in Shanghai as an example, the independent air cooled heat pump system are established respectively, ground source heat pump air-conditioning system. Energy consumption analysis model of hybrid air conditioning system with maximum load in the 7,8 as a unit selection according to two months, dehumidification rate substantially equal as the basis, analysis and comparison of wind parameters, send three kinds of air conditioning system during the operation of the dehumidifying performance, the energy consumption of the unit. The results show that the hybrid air conditioning system with small temperature air in large volume form, ensure the air temperature under the condition of air relative humidity decreases, can improve the indoor comfort. In the part of liquid desiccant regenerator according to the inlet solution temperature of 52 DEG C, the heat exchanger efficiency by 0.7 the design, energy-saving advantages of hybrid air conditioning system is not obvious. When the heat exchanger efficiency increased to 0.8, the comprehensive energy efficiency ratio of the average increase of 0.22, energy-saving advantage.

【学位授予单位】：江苏大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU831

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