基于PLC控制的空调冷却塔循环水泵的变频节能研究
发布时间：2018-07-18 12:36
【摘要】：本文是对惠亚电子科技(深圳)有限公司的中央空调冷却塔系统进行节能的应用研究。在中央空调冷却塔系统中，全压运行的工作方式因结构简单、初期投资少，而在各行各业中得到长期、广泛的应用。但由于全压运行方式的水泵输出功率与负荷的波动无动态变化关系，因而存在严重浪费电能的问题，随着国家节能政策的推进，以及企业营运成本削减需求的高涨，在中央空调冷却塔系统中引入实时控制已成为必须的要求。 首先，针对热负荷情况及空调设备的工作特点，在明确设备的工艺要求条件下，结合循环水泵变频节电原理，分析现场数据后，预估出节能幅度。确定控制对象为冷却水塔的出水温度并提出了3种备选方案，经比较确定采用变频分段自动控制方案（一级闭环反馈方案）。基于PLC控制的空调冷却塔循环水泵变频节能应用研宄具有一定的拓展性：国内各种各样的变频调速的应用汇编并不罕见，有的理论性较强，但多偏重仿真；有的则偏重应用效果而缺乏技术细节介绍。本文力求吸取前辈经验精华，用于改造方案总体设计，并在改造设计前，进行系统失效模式与效果分析，，并制定相应的防范对策。 接着，结合主要部件的性能规格进行如下设计：（1)系统电路图设计：主回路用变频/工频双电源供电方式；变频器用DC mA控制信号，提高抗干扰能力。（2) PLC程序设计：建立冷却塔出水温度（°C)、冷却塔出水温度经A/D转换后的数字量（V)、水泵电动机运行频率（Hz)三者的比例关系，使它们能等量转换，实现控制、比较、显示功能；用区间比较功能指令解决分段自动控制问题；用程序TO/FROM指令，结合专用模块存储器分配表，实现出水温度值的A/D转换和输出频率的D/A转换;(3)触摸屏人机画面设计：监控实时参数、建立累计运行时间档案、设计人工指令如调节受控温度区间和对应的水泵电动机运行频率值、自动/手动方式选择等。 最后,装置用于实际验证。2013年7月投入运行以来，8个月的运行表明：（1)系统无自激振荡、无失控；没有元件损坏。（2)通过电度表对改造前/后的电能用量比较可得：每小时平均用电量节省了31.11%。（3)通过示波器测量改造前/后变频器输入/输出端电压波形，可知新系统的谐波、噪声在可接受水平。
[Abstract]:This paper studies the application of energy-saving in central air-conditioning cooling tower system of Huiya Electronic Technology (Shenzhen) Co., Ltd. In the central air conditioning cooling tower system, the operation mode of full pressure operation is widely used in various industries because of its simple structure and low initial investment. However, since the output power of pump in full pressure operation mode has no dynamic relation with the fluctuation of load, there is a serious problem of wasting electric energy. With the promotion of national energy conservation policy and the high demand for reducing the operating cost of enterprises, the output power of the pump has no dynamic relationship with the fluctuation of the load. It is necessary to introduce real-time control into the cooling tower system of central air-conditioning system. Firstly, according to the heat load and the working characteristics of air conditioning equipment, under the condition of clear equipment process requirement, combined with the principle of circulating water pump frequency conversion and electricity saving, the energy saving range is estimated after analyzing the field data. The effluent temperature of the cooling water tower is determined as the control object and three alternative schemes are put forward. The frequency conversion subsection automatic control scheme (one stage closed loop feedback scheme) is adopted by comparison. The research on the application of frequency conversion and energy saving of circulating water pump in air conditioning cooling tower based on PLC has certain expansibility: the application compilation of various frequency conversion speed regulation in our country is not rare, some theory is strong, but more emphasis is placed on simulation; Some emphasis on application results and lack of technical details. This paper tries to absorb the quintessence of the predecessor's experience and apply it to the overall design of the transformation scheme. Before the transformation design, the failure mode and effect of the system are analyzed, and the corresponding countermeasures are worked out. Then, according to the performance specifications of the main components, the following designs are carried out: (1) the circuit diagram of the system: the main circuit is supplied by frequency conversion / power frequency dual power supply mode, and the DC Ma control signal is used in the converter. (2) PLC program design: the proportional relationship of cooling tower effluent temperature (掳C), cooling tower effluent temperature (V) after A- / D conversion and pump motor operating frequency (Hz) is established, so that they can be converted in equal quantities to realize control and comparison. Display function; using interval comparison function instruction to solve segment automatic control problem; using program TO-FROM instruction, combined with special module memory allocation table, Ar / D conversion of effluent temperature and D / A conversion of output frequency; (3) human-computer screen design of touch screen: monitoring real-time parameters, establishing cumulative running time file, Design manual instructions such as adjusting the controlled temperature range and the corresponding operating frequency of pump motor, automatic / manual mode selection, etc. Finally, the device is used for practical verification. Since it was put into operation in July 2013, the 8-month operation shows that: (1) the system has no self-excited oscillation and no runaway; No component damage. (2) through the watt-hour meter before / after the power consumption comparison can be obtained: the average power consumption per hour saved 31.11. (3) through the oscilloscope to measure the input / output voltage waveform of the inverter before / after the transformation, we can know the harmonic of the new system, Noise is at acceptable levels.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB657.2
本文编号：2131922
[Abstract]:This paper studies the application of energy-saving in central air-conditioning cooling tower system of Huiya Electronic Technology (Shenzhen) Co., Ltd. In the central air conditioning cooling tower system, the operation mode of full pressure operation is widely used in various industries because of its simple structure and low initial investment. However, since the output power of pump in full pressure operation mode has no dynamic relation with the fluctuation of load, there is a serious problem of wasting electric energy. With the promotion of national energy conservation policy and the high demand for reducing the operating cost of enterprises, the output power of the pump has no dynamic relationship with the fluctuation of the load. It is necessary to introduce real-time control into the cooling tower system of central air-conditioning system. Firstly, according to the heat load and the working characteristics of air conditioning equipment, under the condition of clear equipment process requirement, combined with the principle of circulating water pump frequency conversion and electricity saving, the energy saving range is estimated after analyzing the field data. The effluent temperature of the cooling water tower is determined as the control object and three alternative schemes are put forward. The frequency conversion subsection automatic control scheme (one stage closed loop feedback scheme) is adopted by comparison. The research on the application of frequency conversion and energy saving of circulating water pump in air conditioning cooling tower based on PLC has certain expansibility: the application compilation of various frequency conversion speed regulation in our country is not rare, some theory is strong, but more emphasis is placed on simulation; Some emphasis on application results and lack of technical details. This paper tries to absorb the quintessence of the predecessor's experience and apply it to the overall design of the transformation scheme. Before the transformation design, the failure mode and effect of the system are analyzed, and the corresponding countermeasures are worked out. Then, according to the performance specifications of the main components, the following designs are carried out: (1) the circuit diagram of the system: the main circuit is supplied by frequency conversion / power frequency dual power supply mode, and the DC Ma control signal is used in the converter. (2) PLC program design: the proportional relationship of cooling tower effluent temperature (掳C), cooling tower effluent temperature (V) after A- / D conversion and pump motor operating frequency (Hz) is established, so that they can be converted in equal quantities to realize control and comparison. Display function; using interval comparison function instruction to solve segment automatic control problem; using program TO-FROM instruction, combined with special module memory allocation table, Ar / D conversion of effluent temperature and D / A conversion of output frequency; (3) human-computer screen design of touch screen: monitoring real-time parameters, establishing cumulative running time file, Design manual instructions such as adjusting the controlled temperature range and the corresponding operating frequency of pump motor, automatic / manual mode selection, etc. Finally, the device is used for practical verification. Since it was put into operation in July 2013, the 8-month operation shows that: (1) the system has no self-excited oscillation and no runaway; No component damage. (2) through the watt-hour meter before / after the power consumption comparison can be obtained: the average power consumption per hour saved 31.11. (3) through the oscilloscope to measure the input / output voltage waveform of the inverter before / after the transformation, we can know the harmonic of the new system, Noise is at acceptable levels.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB657.2
【参考文献】
相关期刊论文 前1条
1 吕艳;;PLC、变频器在中央空调冷却水泵节能循环控制中的应用[J];自动化技术与应用;2010年08期
本文编号：2131922
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