Research On The Control Principles And Methods Of The Intelligent Thermal Environment In Buildings Based On PMV

With the development of the economy, people’s demand for the degree of thermal comfort inside the room is increasing. Environmental factors and non-environmental factors such as temperature, humidity, radiant temperature, airflow rate, human metabolism and clothing thermal resistance can have effects on human comfort. Although air-condition system plays an important role in building up a favorable indoor thermal environment, traditional air-condition system can only monitor and control indoor temperature and ignores other factors that are related to body comfort. Thus, applying traditional air-condition system alone often leads to the failure in providing more high-quality and comfortable living environment. Besides, while the energy shortage problem becoming more serious, more attentions are given to energy conservation and environmental protection. Traditional air-condition system can neither meet the demand of body comfort nor be beneficial to energy conservation and environmental protection.This research is based on thermal comfort theory, neutral network theory and intelligent control theory. First of all, this research analyzes the effects of the four major environmental factors, which refer to temperature, humidity, radiant temperature and airflow rate, on thermal comfort index. And the results made by MATLAB graphing analysis show that temperature and airflow rate have the significant effects on thermal comfort index, which paves the way for making properly control strategies in following part of the paper. Secondly, by designing a BP neutral network, which has the advantages of simple principle, low computational complexity and high accurateness of results, this research realizes the real time forecast of thermal comfort index. Thirdly, after analyzing the direct and indirect control principle of thermal comfort index, this research makes an air-condition system control strategy and designs a fuzzy PID controller. Finally, this research makes a comparison between the control strategy designed in this research and traditional PID control strategy by simulation experiment. And the results show that the control strategy based on thermal comfort index has the advantage over traditional control, which implies that the strategy that combines energy conservation with body comfort can bring more high-quality comfort.Hence the air-condition system based on thermal comfort index have the advantage of comfort and energy conservation. And the better way to control indoor environment and offer an intelligent thermal environment is to monitor indoor environment and forecast real time PMV index, and then based on that choose the proper conditioning method according to control strategy, which makes full use of indoor airflow.