基于PLC的中央空调水泵变频调速系统设计

届 别2016届 学 号201214240315

毕业设计（论文）

变频技术在中央空调中的节能设计

姓 名 李洋 系 别 、专 业 电子信息与电气工程学院 电气工程及其自动化

导师姓名、职称 曾晓华 副教授 完 成 时 间 2016年3月7号

摘 要

随着我国经济社会的高速发展，建筑能耗在社会总能耗的比例越来越大，已由2007年的24.5%增加到2012年的32%，而大型公共建筑能耗占建筑总能耗的22%，中央空调系统的耗电量占大型公共建筑总耗电量的50%-60%，中央空调系统必将成为建筑节能的重点。在空调系统的实际运行中，首先，绝大多数的空调水系统末端没有连续型电动调节阀，很难实现对空调水系统末端设备的调节控制，加大了水系统的输送能耗。其次，空调水系统在启动时间和启动方式上相差很大，完全凭运行人员主观经验启停空调系统，缺乏科学的决策。另外，在许多变频控制的空调水系统中，水泵变频控制的依据水系统压差监测点位置的选择也多种多样，导致空调水系统循环泵能耗大小不一。因此，针对上述问题，根据对实际空调系统检测和诊断结果，以及空调水系统诸多问题的研究要求，建立通用的空调水系统智能控制试验平台。针对述问题进行研究开发，对降低空调系统运行能耗、建筑节能减排具有重要的学术和实用价值。

首先，本文针对某冲调系统的检测，针对空调水系统控制调节共性问题，设计并建设了中央调系统智能控制试验台，包括空调水系统、电气系统和网络控制系统。在此接础对试验台各设备、管路、传感器、执行机构等机电设备系统的特性进行测试分析，为后续的试验研究工作奠定了试验基础。

其次，本文引入空调水系统最不利水力环路和最不利热力环路的概念，并进行辨析，针对末端没有阀位反馈的空调水系统，提出了以房间温度和供回水温差为参考的空调水系统最不利热力环路辨识方法，通过试验验证了该方法的可行性。

第三，本文针对空调系统的启动时间和启动方式，试验研究空调水系统并联水泵启动台数和上班前预冷启动时间，分析了空调水系统总体能耗大小，结果表明，针对本试验系统中的两台并联水泵预冷阶段时联动要比单独启动一台时能耗要小。

第四，本文针对中央空调的节能问题，对中央空调水泵变频调速系统进行分析及设计。利用可编程控制器、模拟量扩展模块、变频器、温度传感器等代替传统再热量调节系统，实现中央空调水泵的变频调速。通过对空调出口温度

进行检测，变频系统实时调节中央空调水泵转速，达到节能目的。采用变频技术控制中央空调水泵，是当前空调系统节能改造的有效途径。

最后，本文针对水泵变频控制中压差参考点的选择进打研究，试验表明，压差参考点设置在空调水系统主干管中间位置时，循环水泵的能耗最低。

上述问题为空调水系统在实际运行中普遍存在的共性问题，所研究的调节控制方法对实际空调水系统的运行调试具冇较大的参考价值。

关键词：空调水系统；最小利热力环路；水条启动力式；参考点；试验研究，中央空调，变频调速技术，可编程控制器PLC，PID

Abstract

With the rapid development of our economy and society, building energy consumption in an increasing proportion of the total social energy consumption more has by 24.5% in 2007 increased to 32% in 2012, and large public building energy consumption accounts for 22% of the total energy consumption of the building, 50% - 60% of the power consumption of the central air conditioning system for large public buildings of the total electricity consumption, the central air conditioning system will become the focus of building energy-saving. In the actual operation of the air conditioning system, first of all, the vast majority of the water system of air-conditioning terminal no continuous electric control valve, it is difficult to realize regulation and control of the terminal equipment in air conditioning water system, increases the energy consumption of the water system. Secondly, the air conditioning water system in the start time and the start of a large difference, with the operator's subjective experience to start and stop the air-conditioning system, the lack of scientific decision-making. In addition, in many variable frequency control of air conditioning water system, water pump frequency control based on water system pressure monitoring point location of choice is also varied, leading to the air conditioning water system cycle pump energy consumption of different sizes. Therefore, in view of the above problems, according to the test and diagnosis results of the actual air-conditioning system, as well as many problems in the study of air conditioning water system requirements, the establishment of universal intelligent control test platform for water system. The research and development of the problem has important academic and practical value for reducing the energy consumption of air conditioning system, building energy saving and emission reduction.

First of all, this paper for a detection system, common problems of regulation to control the air conditioning water system, design and construction of the central coordination of the intelligent control system of test-bed, including air conditioning water system, electrical system and network control system. The characteristics of foundation on the ground of the experiment the equipment, pipeline, sensor, actuator electromechanical equipment systems are tested and analyzed, and it lays the experimental basis for the follow-up research work.

Secondly, this paper introduces the concept of air conditioning water system is the most unfavorable hydraulic loop and the most unfavorable thermodynamic loop, and analysis, for the end of the no valve