本课题在变水温空调系统运行和节能特性理论研究的基础上，把变水温空调的特性与自动控制理论相结合，提出了一种变水温空调系统的自动控制方法。在已有的热湿换热模型和实验数据的基础上，分析了在部分负荷下，不同冷冻水供水温度对冷水机组和末端设备的性能影响；通过理论数据的分析，得到实际负荷率同末端设备进水温度的关系曲线，并由此提出变水温自动控制的方法；通过实验，对此种控制策略进行了验证；通过实验数据的比较，分析了变水温控制与定水温控制的节能效果。

由本课题的研究和实验分析可知，在集中式空调系统部分负荷运行时，变水温调节可以有效提高冷水机组运行效率，降低运行能耗。采用冷冻水供回水温度及流量可以正确地表达室内实际负荷，冷冻水回水温度作为自动控制系统的反馈值，可以达到变水温自动控制的目的。由此可见，对于中小型中央空调系统，变水温自动控制是一种可行且有效节能的机组优化运行方式。

本课题的研究和实验分析所得出的结论对中央空调系统的实际运行有一定的指导作用，对中央空调系统的节能运行管理有一定的借鉴意义，对中央空调系统的优化运行设计有一定的参考价值。因此，本课题具有较大的实际应用价值。

In the basis of theoretical research of equipments operation and energy-saving characteristic in variable chilled water temperature air-conditioning system, this paper research an auto-control method used in it. This paper, firstly in the basis of a calculating model and experiment data, analyses the effect of different chilled water temperature in partial load, and then, gain the curve between actual load ratio and inflow chilled water temperature. In the basis of the curve, this paper propose an auto-control method and validate in experiment. Finally, this paper analyses the energy-saving effect between variable chiller water system and invariable chiller water system.

From the analyses of this paper, we can know that variable the chilled water temperature adjustment can enhance the operation efficiency and reduce the energy-consumption. As the temperature of supply and return chilled water and the flow of chilled water can truly express the actual load in room, the temperature of return chilled water can be a control value in air-conditioning auto-control system. So it is a feasible and effective regulation model in air-conditioning system.

The results of this paper are important to engineering and air conditioning system design. It will provide the theoretical foundation and design basis for operation and accommodation. And it is significant to the energy-efficiency of air conditioning system. There is certain reference value to the design of the central air conditioning system.