The Control System Research On Temperature Of Central Air-conditioning

Heat environment research results indicate that human body's heat comfort feeling of environment is the combined result of all parameters that make up heat environment on human body, in which the parameters include air temperature, humidity, wind speed, average radiation temperature, etc. The overall effect can be measured by the PMV measurement (Predicted Mean Vote) propounded by Pro Fanger. With the development of national economy and the improvement of people's living standard, people's demand on the thermal comfort of air-conditioned environment is also getting higher and higher. However, the traditional control method in which the indoor temperature is unique controlled parameter and is a constant value is too rough. At the same time, in today's society with energy shortage, people's demand on the air-conditioned environment reaches to the height that comfort and energy conservation are identical important.Aim at these problems, firstly, the PMV index was discussed in this thesis. According to the factors of thermal comfort on influencing air-conditioned environment, the calculation method of PMV index based on BP neural network is established by developing corresponding program in the environment MATLAB 6.5. Then in the presence of the above model, the value of PMV is taken as input, the direct controlling method for the PMV index is realized by applying fuzzy control. The indoor temperature and the wind speed are amended in real time by applying the method. It is seen from the analysis of simulation results that on the prerequisite of meeting thermal comfort, the method can not only make the control action of the air-conditioning system in good time, but also control PMV index in the comfort range. Because PMV index synthetically considers various factors influencing human comfort, it is recognized as the ideal control parameter in the world, and it is undoubtedly the most reasonable to introduce the parameter in order to achieve the temperature control on the central air conditioner.The research results of the thesis have a litter innovation to the traditional air-conditioning control way that is only based on the adaptation to indoor temperature and humidity, which enhances the comfort of air-conditioning system, at the same time, it is favor to make full use of the energy-saving potential.The control method proposed in this thesis is of certain feasible and practical.