Research On Intelligent Control Of Solar Water Heaters Based On Step Motor

With the deterioration of resources and environment, the solar water heaters which use clean and unlimited resource gain a great development. However, in the process of engineering practice, solar water heater, there are some problems such as the frangibility of the collector,which is the important unit of the solar water heater, difficult both to thermostatic control the hot water and to get hot water immediately, and waste of water resources.This paper designed an intelligent controller for solar water heater to achieve constant temperature water, safe water, water conservation.First of all, this paper designed a protection device for solar water heater’s collector. The protection device used a kind of semicircular protection cover which has a coat that can reflect the light in both sides of it, and the cover is set on the collector and can rotate around it. The control system includes:1) an automatic control mode which have a temperature sensor and a light sensor to detect the temperature of the water and the illumination of the environment thus to control the rotation of the protection cover automatically;2) an artificial control mode that gives the user more freedom in controlling and the user can use this mode to force the protection on thus to prevent the collector from breaking down due to the high temperature generated in the empty collector when the user is leaving home for a long period. All in all, the design has a low cost, high intelligence, and is very applicable.Second, in accordance with large delay and non-linear of temperature system, in order to improve the control accuracy, a new thermostatic mixing device is designed with step motor as its actuator, and also come with a logic rules control algorithm based on Pan-Boolean algebra. This method does not need to establish a precise mathematical model, it can make decisions according to the difference of deviation and change rate. Simulation results show that the system has greatly enhanced the accuracy of water-mixing, as well as shorten the mixing time, and it keeps characteristics of simple algorithm, easy operate and so on. At last, the paper without changing the original solar water heater structure, existing single conduit to double tube, design a solar water heater i.e. thermal effluent water saving device. This device using pumps provide motivation, to achieve the water cycle, again through the single-chip microcomputer control relay to two points, controling water temperature and saving the water.