公共建筑冷却塔台数调节节能运行分析

Energy-Saving Operation by Regulating the Number of Cooling Tower in Public Buildings

在空调系统非满负荷条件下,合理利用未启动制冷主机配套的冷却塔,降低制冷系统整体电耗,实现制冷主机与冷却塔综合电耗最低。利用麦克尔焓差理论公式建立机械通风冷却塔数学模型,分析不同空气湿球温度、风量、水量条件下冷却塔出水温度变化。分析结果表明:随着冷却塔气水比增加,冷却塔出水温度线性降低;随着湿球温度降低,气水比变化对冷却塔出水温度的影响变大。降低冷却水进口温度可以降低冷水机组电耗;增加冷却塔气水比导致冷却塔风机电耗增加。同时考虑冷水机组变工况特性及冷却塔变工况特性,分析得出:单台冷水机组配套运行其1.4~2.0倍额定冷却塔数量的条件下,冷水机组和冷却塔运行总电耗最低。同时,为冷水机组选择配套冷却塔时,建议选择2台机组对应4个单元冷却塔或3台机组对应6个单元冷却塔的配置方式,为后期节能运行预留条件。

Under the condition of non-full load of air conditioning system, rational using the no starting cooling towers those matched with the refrigeration host will reduce the overall power consumption of the refrigeration system, and achieve the lowest comprehensive power consumption for refrigeration host and cooling towers. The mathematic model of cooling tower with mechanical ventilation, which is established with Merkel enthalpy potential equation, analyzes the outlet water temperature variation under the conditions of different wet bulb temperature, wind and water flow rate. The results show that in the cooling tower, the outlet water temperature linear decreases when gas-water ratio increases, and it is impacted more by the variation of gas-water ratio while the wet bulb temperature decreasing. The water chiller’s power consumption can be reduced by decreasing the import water temperature, and fan’s power consumption of the cooling tower will be increased by raising the gas-water ration. With the consideration of the characteristics of water chiller and cooling tower working under the variable conditions, results in the analysis also show that water chiller and cooling tower operate with the lowest power consumption under the condition that the single water chiller works with 1.4~2.0 times by the rated sum of cooling towers. While choosing cooling tower to match water chiller, suggest to follow the allocation method, which two water chillers match four units cooling towers or three match six units, to allow preparation for later energy-saving operation.