Research On The Energy-saving Improvement Of A Certain Central Air-conditioning System

At present, with our country’s large-scale public buildings construction areaincreased year by year, the high-energy consumption in the buildings is gettingmore and more attention. Because of the central air conditioning system energyconsumption accounts for a large proportion in the building energy consumption,the energy-saving operation of the central air conditioning system became thekey pathway to save the building energy consumption.Based on the test of the actual operating conditions of a hospital’s central airconditioning system, and combined with calculating the defined air conditioningsystem energy efficiency index values, this paper list some irrational operationmodes in the system. For the specific questions, this paper proposed somecorresponding measures to improve the system operation conditions, such as thechilled water system with variable primary flow and variable temperature and soon.For different operation modes this paper proposed different air-conditioningsystem energy consumption calculation methods. By determining the actualoperating points of the chilled water pumps at part load ratio, here the paper putforward the chilled water pump energy consumption calculation methods. Andcombined with the performance parameters of the variable chilled water chiller,we can calculate the energy consumption of the variable primary flow chilledwater system;In this paper, it also shown how to use the Visual Basic language to programa simple cooling coils program to calculate the actual performance of the coolingcoils. And at the same time, it also can be used to analyze if the temperature orthe room relatively humidity is confined within the comfort range.Through thecalculation of the cooling performance of the cooling coils, we can reset the chilled water supply temperature when the cooling load is at different part ratio.To be able to analysis the affect of the measures that proposed to improvethe energy efficiency accurately, the paper modeled the original air-conditioningsystem and the improved systems by using the energy simulation software(Trnsys) to simulate the system energy consumption during the overalloperating seasons. Through simulation, the results shown that the variableprimary flow chilled water systems can achieve air-conditioning system energysaving by7.4%relative to the constant chilled water flow system, while the useof variable temperature operation system can realize energy saving potential of3.9%.