Application Study Of Neural Networks PID Controller In The Capillary Radiant Integrated With Displacement Ventilation Air Conditioning System

With the reduction of the world's energy and the aggravation of environmental pollution, people are more and more popular for the air conditioning system with high efficiency, energy saving and high comfort performance. Compared to the traditional air conditioning system, capillary ceiling radiant air conditioning system can cool the room with high-temperature chilled water and heat it with low-temperature hot water, and it has great potential for energy saving. And its common use with the displacement ventilation system can ensure the comfort of the room effectively. Ground source heat pump as an energy-efficient cold and heat source, which works well, is an suitable choice for air conditioning system. Therefore, from the point of view of the system optimization, this paper puts forward a new kind of hybrid system—the ground source heat pump + capillary radiation + displacement ventilation air conditioning system.In this paper, a serviced apartment in Wuhan is taken as the research subject. And the method for controlling supply water temperature of the capillary radiation air conditioning system by using the neural network PID controller is presented, and the control program is written in MATLAB. Then, study on the indoor comfort, condensation, energy consumption of the system and the average soil temperature of buried pipes under the years of operation, and analyse the indoor comfort and the annual energy consumption with different indoor design temperatures in winter and summer of the hybrid system by developing the model of ground source heat pump + capillary radiation + displacement ventilation air conditioning system in TRNSYS program.The simulation results show that the method for controlling supply water temperature of the capillary radiation air conditioning system by using the neural network PID controller can ensure that the indoor temperature is maintained at the design temperature with the fluctuation being within a range of ±0.3 °C. The air supply mode of fresh air system is different in different seasons. It sends the fresh air with either high or low velocity in the summer and with the volume whith meets the health requirements of the room in the winter. With this method, the relative humidity in the room can be guaranteed in a reasonable range and condensation phenomenon does not appear, realising the high comfort environment in the interior. Moreover, it can not only ensure the indoor comfort, but also has obvious energy saving effect if the indoor design temperature is reduced by 1~2°C in winter or increased by 1~2°C in summer. Finally, in view of the soil heat accumulation problem of the hybrid ground source heat pump system in hot summer and cold winter zone, the model is simulated for 20 years and the average temperature of the soil increases by 3.66°C, which proves that the hybrid system is feasible.