Research On The Indoor Ventilation And Temperature Automatic Control System For Small Size House

With the acceleration of the urbanization process in China, large numbers ofpeople is getting into cities, and problems of housing is becoming seriously. In thiscase, small family housing has become the best choice for low-income people.However, due to room constraints, the normal natural ventilation is hardly to carry out;and Because of the unseeing and popularization of air conditioning, the fresh air in theroom can’t meet the peoples’ requirements, the indoor pollution can’t be eliminated,the indoor air quality become bad. People’s health and normal life is seriouslythreatened.In this study, by controlling the indoor ventilation and temperature, to create asafe indoor air quality environment and a comfortable thermal environment, to meetpeople’s requirements of the indoor air quality and temperature. Based on the analysisof the control methods and requirements for residential ventilation and temperature,Indoor environmental control system based on microcontroller is built. By using theFLUENT software, the carbon dioxide concentration and temperature field weresimulated under different indoor situations. The main research works are as follows:(1) The way of ventilation and temperature regulation are designed. By referenceto the two-way flow system, the displacement ventilation is chosen to be the indoorventilation. Temperature is adjusted by the semiconductor cooling pieces and the PTCheating element installed in the ventilation pipe,and the electric control valve installedon heating pipes.(2)The hardware and associated circuitry is designed. In it, ATmega16is thecontrol center; temperature sensor DS18B20and carbon dioxide sensor MG811aredetection components; the keyboard and LCD are used to control and display,and theperipheral circuits for components are designed, in order to ensure the smoothoperation of the circuit.(3) Using AVR Studio and CVAVR as software development platform, the drivecontrol program is written in the C programming language, include overall systemmain program and the drive control program for every component.(4)Using Fluid simulation software FLUENT to simulate of the indoor environment. Indoor geometric model is built by GAMBIT. Indoor carbon dioxideconcentration field and temperature field changes are simulated under differentconditions by changing the boundary parameters. And use these dates to guide thecontrol parameters of the system. All these have important significance for theoptimization of the design and reduce the cost of design and debugging.