The Optimal Design And Diagnosis Of Chilled Water System On Suboptimal Method

As the energy consumption of central air conditioning system account for a large proportion in building energy consumption,it has attracted much attention.But,unreasonable initial design of air-conditioning system and unscientific operation and control prompt energy consumption remain high,the main reason of most energy consumption being wasteful is it.When large central air-conditioning system uses intelligent control system to achieve energy saving,the severe problem with poor adjustment,poor stability,poor energy efficiency,hysteresis urgent need solve in process of operation with the characteristics of multivariate,nonlinear,highly coupled for air-conditioning.The premise of optimized operation control and stable operation is optimal design of large air-conditioning system,so it is extremely necessary that the cold load and pipe diameter of each pipe section for chilled water system is reasonable designed,in order to operate with lower energy consumption in different condition.The model of comfort fan-coil and hydraulic characteristics of pipe network,suboptimal calculation analysis are established to research existing chilled water system operating with lower energy consumption in different load rate.The density of population in air-conditioning area with 16 AHUs in reversed and direct return system is simulated calculation and analyzed.The minimum energy consumption of pipe network is used for optimization objective function,the suboptimal algorithm of variable step size combining with the random walking is adopted to suboptimal calculate to achieve suboptimal group with certain control value.By analyzing statistical law and random behavior of suboptimal group,the solution of suboptimal group accord with hydraulic characteristic of pipe network,and the chilled water system operate in low energy consumption in different load rate.The result sufficiently account that suboptimal algorithm is available for research distribution mechanism of occupant density in air-conditioning area and it can provide reference value for optimal design of chilled water system,it has short time of calculation and jump out local optimum solution to seek optimum solution.In order to research the range of pipe diameter of chilled water system,in the paper,the model of reversed and direct return system including 20 AHUs is respectively established,and the pipe diameter of pipe network is randomly valued,the cost of equivalent uniform including initial cost and annual operating cost is used as objective function to optimal calculation.According to the suboptimum group,statistical laws and random behaviors are gained,and the reference range of pipe diameter of each pipe is worked out.At the same time,the air-conditioning system of office building is monitored and simulated,according to comparative between that the practical data and mass data of simulate malfunction,and fault detection of AHU(air handing unit)in air-conditioning system is explored.