The Optimization Of Electronic Plant Cooling Tower Free Cooling HVAC System And Its Regional Adapatibility Analysis

As China’s economy continues to develop, the importance of energyconservation is becoming increasingly prominent. Industrial buildings aregiant energy users, the burden of energy conservation is facing towards theenergy-hungry society. As the energy consumption of air conditioningsystems account for30%to50%of the total building energy consumption,it is the focus to be optimized.Cooling Tower Free Cooling is a technique that will make use of theenvironmental cooling source to shoulder part or the entire system coolingload when meteorological conditions meet the requirement, thus makingthe HVAC system more energy-saving. The electronic industry has beendeveloped in China for more than80years, becoming an important pillarof the national economy. With this background, we choose the electronicfactory to be the research object in this article; the factory is characterizedas its annual cooling load is stable and less volatile. In this context, thispaper has taken a typical electronic plant cooling tower free cooling HVACsystem to be the object and accomplish the application analysis, researchanalysis and economic analysis of energy-saving and other aspects.Firstly, according to the composition units and characteristics of thesystem, we build up the mathematical model and the digital simulator ofthe electronic plant cooling tower free cooling HVAC system. On this basis,this paper also designed a corresponding basic control system, includingoperation mode control strategy and the chillers on/off control strategy.Secondly, we have made analysis of the free cooling system’s energysaving potential according to the meteorological data of six selected typical cities. By this means, we can study and explore the impact of regionaldifference on the system’s potential. What’s more, we have come up with anew indictor-Free Cooling Energy Saving Ratio-to replace the oldone-Accumulative Free Cooling Hours, because the later one has someweaknesses. The Free Cooling Energy Saving Ratio can exclude thesystem’s load interference and make a good estimation of the HVACsystem’s energy saving potentialThirdly, this paper analyzes the major factors which will affect theenergy consumption of the electronic factory cooling tower free coolingHVAC system and tests different optimization measures on the digitalsimulator to explore the impact of each factor can be made on the system’sFree Cooling Energy Saving Ratio. The optimization measures is consist ofthe change on the chiller water supply set temperature, the cooling waterdistribution strategy under the combined operation mode, the operationmode switch strategy and the performance parameters of the equipment(cooling tower and heat exchanger).Finally, in order to analyze whether those optimization measures canbe employed in different regions, we have tested the Free Cooling EnergySaving Ration of typical system in6cities using the same optimizationmeasure. The result shows that the energy saving potential of the electronicplant cooling tower free cooling HVAC system changes according to theregions. What’s more, we have selected the Dynamic Investment Pay-backPeriod as the economic indicator to study the system’s economicalefficiency and the result demonstrate that different region has differenteconomical efficiency.