Study On Energy-saving Operation Of Central Air-conditioning Water System Based On Genetic Algorithm

The widely-used water system is a considerable part of energy consumption in central air-conditioning system.This thesis takes water systems of central air-conditioning as the study object,and aims to realize the energy-saving and intelligent optimization of central air-conditioning water system without replacing the equipment of the original system.The specific study contents of this paper are as follows:(1)A central air-conditioning water system experimental device with good stability was built.Specific work includes the design of the experimental device,the selection and installation of flow,pressure and temperature measuring instruments.The energy efficiency monitoring software was designed and tested.When the confidence factor is taken as 2,the test results introduced by the experimental device due to fluctuations are as follows: the temperature measurement error is less than 0.2℃,the flow measurement error is less than 0.2m3/h,the head measurement error is less than 0.4k Pa,and the electric power measurement is less than 4W.(2)The energy consumption model for central air-conditioning water system was established.Based on the theoretical analysis,the mathematical models of compressor,chilled water pump and cooling water pump were established,and the average relative error is less than 3%.Through the analysis of the physical constrains of the internal and external of the equipment parameters,the frequency control model of the central air-conditioning water system was proposed.(3)The energy-saving genetic algorithm for the central air-conditioning water system was designed.Based on the analysis of the operating characteristics of the central air conditioning water system,the necessity of the optimization algorithm to solve the energy saving operation problems was proved.Based on the study of genetic algorithm to solve the optimization problems,the energy-saving operation algorithm of central air-conditioning water system based on MATLAB software was designed.(4)The optimization effect of the genetic algorithm on energy saving operation of the water system was studied and analyzed.The rationality of the energy-saving operation algorithm design of central air-conditioning water system was verified by the convergence process of the algorithm.And the control principle of the output strategy of the algorithm was explained from the operating principle of the central air-conditioning system.The operating parameters and energy efficiency changes of the system before and after optimization of the genetic algorithm was experimental analyzed.The experimental results prove that the designed genetic algorithm has energy-saving effect on the operation of the central air-conditioning water system.In the design load range of 30%~70%,the average energy-saving rate of the compressor,chilled water pump and the cooling water pump are 16.8%,51.0% and 55.0%,respectively.The maximum energy-saving rate of the central air-conditioning water system is 37.4%,the minimum energy-saving rate is 15.5%,and the average energy-saving rate is 26.8%.