Research On Energy Efficiency Grading Evaluation And Application Of Air Conditioning System In Public Buildings

With the development of society and people's demands for indoor environment,the energy consumption of buildings and their air-conditioning systems is also increasing.The energy consumption of public buildings,which only account for 5% to 6% of the total building area,is more than 10 times that of residential energy.In the total energy consumption of public buildings,the energy consumption of air conditioning systems accounts for 40% to60%.The energy saving potential of air conditioning systems is enormous.This paper takes the energy efficiency of air conditioning system as the research object,summarizes the advantages and disadvantages of different evaluation indexes of energy efficiency of air conditioning system,analyzes various factors affecting the energy efficiency of air conditioning system,and starts from the various equipments of air conditioning system to calculate different energy efficiency evaluation indexes of air conditioning system..Through field research on a number of air-conditioning projects,as well as collecting sample parameters of different equipment in the air-conditioning system,the performance coefficient of the air-conditioning unit and the water transport coefficient are determined as the main evaluation indicators for studying the energy efficiency of the air-conditioning system.The influence of design energy efficiency on the energy efficiency of the system is analyzed,and the relationship between the performance coefficient of the chiller under non-full load and the performance coefficient of the unit and the energy efficiency of the whole air conditioning system under actual load is analyzed.The effects of chilled water inlet and outlet water temperature and cooling water inlet and outlet water temperature on the energy efficiency ratio of air conditioning system were studied.Taking a central air-conditioning system of a public building in Beijing as an example,the actual energy consumption of the air-conditioning system is measured,and the parameters such as water temperature and flow rate during the operation of the system are measured,and the actual cooling capacity is calculated.The DeST is used to simulate the annual cooling load of the building,and the actual cooling capacity is compared and analyzed.According to the previous analysis,the energy-saving transformation method of the air-conditioning system is proposed.The air conditioning system was energy-savingly modified by the method of chilled water pump frequency conversion + cooling water pump frequency conversion + cooling tower fan frequency conversion and cold machine cooling / chilled water temperature comprehensive control.Calculate the performance coefficient of the chiller before and after the transformation,the water transport coefficient of each system,the energy efficiency ratio of the air conditioning system and other indicators,and compare the energy efficiency ratio ofthe cold station after the transformation is 17.5% higher than that before the transformation,indicating the energy-saving transformation of the air conditioning system.It has a certain effect.The research in this paper provides a method for energy efficiency evaluation of air conditioning systems,which is of great significance for energy-saving renovation of air conditioning systems.