既有商业建筑冷源系统节能诊断及优化

Energy-saving Diagnosis and Optimization of HVACs in Existing Commercial Buildings

北京某商业建筑的空调面积8.81万m^(2),原设计东、西区及超市3个制冷机房,原空调系统冷水机组总装机容量约为5757RT,现阶段实际供冷量为装机值的40%~60%,存在冷机初投资高、冷机运行负荷率低、冷机闲置、水泵效率低等问题,冷站综合效率约为3.1,冷却水输配系数平均值为23.05,冷冻水输配系数平均值为13.75,远低于空调系统节能运行标准要求。基于实际空调负荷测算及水系统压降分析后,将该项目东西区部分业态空调系统进行合并,通过优化冷机总装机容量、二级泵系统改一级泵系统等措施,提高了冷机负荷率和COP,并提升了冷冻水输配系数。改造后,在10%~100%负荷率范围内,冷水机组综合COP提升至5.5以上,考虑水泵能耗后,冷站总体能效由改造前的3.1提升至4.0左右。该案例为具有相同问题的既有建筑节能改造提供指导。

HVACs of a commercial building,air conditioning area of which is 88100 m^(2),in Beijing is diagnosed and improved.Rated capacity of water chiller units is 5757RT,which is 1.7 to 2.5 times of the actual cooling demands.This leads to problems of high initial investment,low load ratio of chillers and low efficiencies of pumps.For the existing HVACs,the efficiency of chiller plants,chilled water pumps and cooling water pumps are around 3.1,23.05 and 13.75,respectively,which are much lower than the energy saving standards of HVACs.Based on cooling load calculation and pressure drop analysis of chilled water loops,it is decided to combine air conditioning systems of east and west parts of this building.Based on this,total rated capacity of chiller units is reduced and operating strategies under different load ratio are proposed.Besides,the original two-stage chilled water pumps system is transformed to be single stage system.These strategies can effectively increase COP of chillers and transportation coefficient of chilled water pumps.When load ratio is in the range of 10%to 100%,COP of chillers is increased to be over 5.5.When energy consumption of pumps is taken into consideration,efficiency of chiller plants is enhanced from 3.1 to 4.0.This commission case provides guidance for energy saving diagnosis and transformation of existing commercial buildings that have similar problems.