Study Of Embedded Remote Controller For Air Conditioning Based On GSM

The terminal device is the most numerous used equipment in heating ventilating and air-conditioning(HVAC) system.The existing terminal air-conditioning control of HVAC system is based on bus-mastering or independent controller,and running of the equipment is controlled according to a fixed scheduling time or manual field control.However,it only applies to those users who have regular work and rest schedules.Flexible adjustment of the start-stop time of the terminal air-conditioning according to users' actual needs and the environmental temperature and humidity,as well as its remote control of pre-start-stop are keys to save energy and improve comfort of the HVAC system.The structure of the HVAC system and its air conditioning theory are analyzed,and the optimal strategy of start-stop control for terminal devices of the HVAC system is developed,with which the actual start and stop times are determined based on the temperature curve of last running and the actual environmental conditions.Based on the above-mentioned control strategy,the embedded controller as well as the driving hardware and power matching circuit are designed using Samsung S3C2410 CPU and Linux embedded operating system.Based on the hardware platform mentioned above,the cross-compiling environment of software development is established for the embedded controller of terminal devices of the HVAC system.Further more,clipping and compiling of the Linux kernel,establishment of the root file system,design of application programs, and overall design of controlling software are accomplished.On this basis,the embedded software is developed for optimal start-stop control algorithm of the equipments,digital incremental PID control algorithm subroutine of the temperature loop control,subroutine of temperature sampling filtering,subroutine of the adjusting valve driving,and subroutine of SIM card communications.Remote control of air-conditioning can be realized by means of cell phone messages according to users' demands.To test the above-mentioned controller,experiments are made on the experimental HVAC model in the laboratory,with the results indicating that the controller can remotely control the terminal air valve by means of cell phone messages.Furthermore,this controller can automatically adjust the equipments' start and stop times according to users' expected time of achieving comfort and temperature conditions,as well as the current environmental temperature and humidity,save energy while improving comfort level of the air conditioning.