| Building a resource-saving society which highlights energy-saving strategy isChina’s strategic decision and the only way for our social sustainable development.Currently, with the ever-increasing building quantity and higher requirement forindoor comfort, building energy consumption is on rapid increase in China.According to correlational studies, building energy consumption accounts for20.9%of social total energy consumption, in which energy consumption for public buildings(heating energy consumption in northern area of China is excluded) makes up25.6%.In public buildings, air-conditioning energy consumption makes a big share intotal energy consumption. Therefore, the study of energy efficiency evaluation forair-conditioning system and its subsystem plays an important role to improve energyefficiency and decrease public building energy consumption.Based on the concept of energy efficiency ratio (EER), this paper buildsevaluation methodology for energy efficiency of air-conditioning system andsubsystem. Refer to related standards and codes, EER limitation of air-conditioningsystem and subsystem is worked out. The study evaluated energy efficiency for theair-conditioning system of an existing building with this method, analyzed theexisting problem, and made reasonable energy-saving reformation scheme.Furthermore, the study revaluated the reformed system and discussed the variation ofenergy efficiency. Through the evaluation, this paper established the evaluationmethodology for energy efficiency of air-conditioning system, and verified the correctof the methodology.Then taking the existing air-conditioning system as an example, the paperdiscussed energy efficiency ratio of chillers and chilled water system on two differentcontrol schemes: constant terminal differential pressure and combination of constantterminal differential pressure and temperature difference. It is indicated thatoperation energy efficiency ratio of chillers in the first control scheme is240.7%higher than the second one; while that of chilled water system is10.1%lower. Whenthe two parts are studied as a whole, the comprehensive operation energy efficiencyratio in the second control scheme is6.7%higher than that in the first one, which indicates that the system has better energy-saving potential in the combination controlscheme.In the last paper, it proposes one control scheme: adjustment of air conditioningcold water temperature based on system forecasting load by stages. And it analysesthe annual operating energy efficiency ratio of the air conditioning system, the reultsshows that the control scheme has advantages in energy-saving and the feasibility ofimplementation. |
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