冷水机组模型，利用仿真程序TRNSYS基于质量和能量守恒定律的发展。采用经典换热器效率方法对蒸发器和冷凝器进行建模。整个模型由一组方程组成。能量平衡的一般方程和假设在冷水机组模型已报告[ 5，9 ]。该程序，以确定操作变量的冷水机组模型提到的流程图报告[ 9 ]。该计划开始与模型初始化使用输入数据。由于制冷机的制冷负荷可以在制冷回路中随机共享，应首先确定CLS的策略。然后，蒸发温度和电路1和2的压力（tev1，tev2，FEV1和pev2）和三段换热器的冷负荷（Q11、Q12和Q2）计算通过一个迭代过程，通过假设一个初始值。一旦模型确定的蒸发温度和压力的电路1和2，该模型评估每个制冷回路的状态变量。由于冷凝温度之间的压缩机和冷凝器组件相互作用，迭代过程来实现两个组件同时解决的操作变量。为了控制冷凝温度，有另一迭代循环确定的数量的分级冷凝风扇。根据冷凝温度设定点计算了分级凝汽器风扇的数量和相应的气流。

The iterative procedures to estimate the heat rejection, the operating variables and the cooling load in both refrigerant circuits of the chiller were similar。 The convergence criterion for computing condensing temperature and evaporating temperature in this model was 0。01 °C。 When a converged solution was obtained, all the variables of the model would be computed with the required accuracy。   

迭代程序来估计的散热，制冷压缩机的两个制冷剂电路的操作变量和冷却负荷相似。该模型计算冷凝温度和蒸发温度的收敛准则为0。01°C，当得到收敛解时，所有模型的变量都将根据所需精度计算。

2。3。 Validation of the chiller model 

2。3。冷水机组模型的验证

To verify the effectiveness of the developed modeling technique, the performance of the model was evaluated by comparing the modelled results with the operating data of the chiller。 The measured data collected for validating the chiller model came from the chiller operating data under HPC, which covered a wide range of operating conditions (Tdb: 18–35oC; PLR: 0。2–1。0)。 Fig。 2 shows that the modelled results of the chiller’s COP agreed well with the corresponding COP calculated base on the measured data。 Allowing for the experimental uncertainty of COP, being 3。2%, and the dead band for determining switching on one more or less condenser fan, which could result in COP depart from the measured ones, the deviations were within the allowable tolerance。 With this good agreement, the simulation results, therefore, were considered to be satisfactory。 

为了验证所开发的建模技术的有效性，该模型的性能进行了评价，通过比较与冷水机组的运行数据的模拟结果。测量数据采集验证机组模型来自冷却器的运行数据下的高性能混凝土，它涵盖了范围广泛的操作条件（TDB：18–35oc；PLR：0。2–1）。图2表明，模拟结果的冷水机组的COP同意以及相应的COP计算的基础上测得的数据。允许实验的不确定性COP，为3。2%，和死区确定开关上一个或更少的冷凝器风扇，这可能会导致COP偏离测得的，偏差是在允许的公差范围内。有了这个良好的协议，仿真结果，因此，被认为是令人满意的。

Fig。 2。 Comparison between the modeled and measured chiller COP。 

3。 Cooling loads of the office building 

3。办公楼的冷负荷

In order to assess the energy efficiency by optimal CLS for air-cooled chillers with multiple refrigeration circuits in air-conditioned buildings, the cooling energy saving potential for a representative office building in Hong Kong was investigated when different control strategies of CLS were implemented to the air-cooled chiller plant。 According to a survey of 64 commercial buildings in Hong Kong [10], the construction characteristics of high-rise office buildings were identified and a reference building was developed as the basis for simulation, which was a squared office building (36 m by 36 m) with 40 storeys。 Hourly cooling loads for the representative office building were calculated using EnergyPlus and a typical weather year which represented the prevailing weather conditions in Hong Kong。