中央空调循环水节能控制系统的设计

摘 要

本文针对变频控制是针对水循环（包括冷媒水、冷却水循环）而言。通过采用变频器，根据空调末端的需要，调节冷媒水泵、冷却水泵的工作频率，改变系统中的冷媒水量和冷却水量，以此来达到节能的目的。这种节能控制方式也称为中央空调的变流量节能控制。

控制冷冻水的回水温度，当余户的负荷变化时，回水温度作出相应的变化；控制冷却水的出水温度，即可控制温差。当系统负荷加大时，产生的热量增多，导致出水温度超过给定值，此时PLC控制变频器使循环水泵加速，水泵流量加大使出水温度降至原设定值，反之，当系统负荷减小时，出水温度降低，PLC控制变频器使循环水泵减速，水泵流量减小，出水温度升至给定值；通过采用变频器，根据空调末端的需要，调节冷媒水泵、冷却水泵的工作频率，改变系统中的冷媒水量和冷却水量，以此来达到节能的目的。

关键词：中央空调，变频调速技术，可编程控制器PLC，PID 

Abstract

In this paper, frequency conversion control is for water cycle (including refrigerant water, cooling water cycle). In order to save energy, the frequency of refrigerant pump and cooling pump are adjusted according to the need of air conditioning terminal by using frequency converter, and the quantity of refrigerant water and cooling water in the system is changed. This energy-saving control method is also known as central air-conditioning variable flow energy-saving control.

When the load of the remaining household changes, the backwater temperature changes correspondingly, and the temperature difference can be controlled by controlling the effluent temperature of the cooling water. When the system load increases, the heat produced increases, which results in the temperature of the effluent exceeding the given value. At this time, PLC controls the converter to speed up the circulating pump, and the flow rate of the pump and the temperature of the outlet water drop to the original set value, whereas, when the system load is reduced, PLC control the circulating water pump to slow down, the flow rate of the pump decreases, and the effluent temperature rises to the given value; by adopting the frequency converter, according to the needs of the air conditioning terminal, the work of the refrigerant pump and the cooling pump is regulated. The frequency of cooling water and cooling water in the system is changed to achieve the purpose of energy saving.

Keywords: central air conditioning, variable frequency speed regulation technology, programmable controller PLCU pid