Study On Changing Dew-point Temperature Of Supplying Air And Control For Variable Air Volume Air-Conditioning System

Heating,ventilating and air-conditioning(HVAC)control systems are the most important part in the building automation systems(BAS),especially from the viewpoint of saving energy and improving the indoor air quality.Building automation systems (BAS)will become more and more important in heating,ventilating and air-conditioning(HVAC).So it is very significant to adopt the efficient air conditioning methods to manage the energy management control(EMC)of intelligent building.At present,variable air volume(VAV)air-conditioning system is the mainstream of the whole air conditioning system in china and abroad because of its large energy conservation.To make use of variable air volume(VAV)air-conditioning system in factual engineering,some works have been done below.First,analyze the direct reason of variable air volume(VAV)air-conditioning system for it can not enhance relative humidity's precision.Through calculating, establish changing dew-point temperature VAV system.From theoretical analysis we can learn that the method is effective and feasible.Establish Elman neural network model for dew-point temperature forecast.Experiment shows that this way can best forecast dew-point temperature for variable air volume(VAV)air-conditioning system, which paves the way for the approach of changing dew-point temperature for variable air volume(VAV)air-conditioning system.To solve the control problem for changing dew-point temperature from the point of view of control and to improve the control precision of relative humidity and temperature,System identification method has been adopted,by which establish the transfer function for Valve- supply air temperature,prove the feasibility of the control for changing dew-point temperature and improve the efficiency of the precision of relative humidity.Changing dew-point temperature not only can improve the control precision of relative humidity,but also can save energy proved by energy analysis which can make the rational use of the energy. Finally,to control the dew-point temperature for variable air volume(VAV) air-conditioning system,a PID Control arithmetic based on BP Neural Network has been adopted.Simulation shows that PID Control arithmetic based on BP Neural Network has a better control effect than PID Control arithmetic.