Intelligent instrument of the hottest solar water

Solar water heater intelligent instrument

Abstract: at present, there is a shortage of energy and electricity. Solar energy is a green energy, which is loved by the majority of users. Problems when using solar water heaters: do not lack water, and the water supply will explode when exposed to the sun; In spring and autumn, the water temperature rises and evaporates, causing heat loss; In winter, the water temperature is not enough and electricity is needed. The above problems can be solved by using the intelligent instrument of solar water heater (the instrument is called the measuring and controlling instrument of water temperature and level of solar water heater). It makes users worry free, easy to use, intelligent operation, and users do not have to do anything

key words: working principle of solar water heater technical performance introduction at present, there is a shortage of energy and electricity. Solar energy is a green energy, which is loved by the majority of users. Problems when using solar water heaters: do not lack water, and the water supply will explode when exposed to the sun; In spring and autumn, the water temperature rises and evaporates, causing heat loss; In winter, the water temperature is not enough and electricity is needed. The above problems can be solved by using the intelligent instrument of solar water heater (the instrument is called the measuring and controlling instrument of water temperature and level of solar water heater). It makes users worry free, easy to use, intelligent operation, and users do not have to do anything. Solar energy is a kind of energy with low density, intermittent and changing spatial distribution, which is very different from conventional energy, which puts forward higher requirements for the collection and utilization of solar energy. In the utilization of solar energy, in order to obtain medium and high temperature heat energy, the collector must track the sun from sunrise to sunset. In solar photovoltaic, under the same conditions, the power generation capacity of automatic tracking power generation equipment is 35% higher than that of fixed power generation equipment, and the cost is reduced by 25%. Therefore, in the use of solar energy, it is a very meaningful work to study the control mode of the tracking device. 1. The technical performance requirements of this topic: (1) the power supply is 220V AC, and the power consumption is 5W. (2) Water temperature digital display, temperature measurement range 0~99 0C; Accuracy ± 20c. (3) The water level is displayed in five levels (water shortage, 20, 50, 80, 100%). (4) It has the functions of water shortage, temperature control, manual and low water pressure. (5) Water level setting. Water levels of 20, 50, 80 and 100% can be set (the preset water level of this instrument is 50%). (6) Water shortage alarm. When the water level changes from high to low and there is water shortage, the buzzer will alarm and the water shortage indicator will flash. 2. Working principle: 2.1 principle: use thermistor and liquid level sensor to detect and display the water temperature and water level. Control according to the water temperature and level. When the water level is from high to low, and there is a water shortage state, the buzzer alarm will sound, and the water shortage indicator light will be on, delaying 15 minutes. If the temperature does not exceed 990c (to avoid pipe explosion caused by watering after drying), the water will be automatically fed to the preset water level; If the temperature is higher than 1000C, do not add water. After the sun shines, the water temperature rises. When the temperature exceeds 600C and the water is not full, open the battery valve to fill the water to 500C; Prevent unreasonable phenomena of low water volume and high water temperature. In the evening, if the hot water has been used up, delay 15 minutes to supply water for lack of water; If the hot water is not used up, do not add water to ensure the full utilization of hot water; After the sun comes out the next day, use temperature control to add water. In the process of water filling, if the water pressure is too low or the water is stopped, the intelligent instrument will automatically enter the low water pressure water filling mode. The low water pressure audible and visual alarm will start the water filling at an interval of 30 minutes. If the water level cannot rise by one gear within 30 minutes, it will stop for 30 minutes, then start it again and cycle repeatedly. In order to prevent the battery valve from burning due to long-time power on. 2.2 implementation scheme: (Appendix 1: system schematic diagram) the water level can be set through the "water level setting" key, and the water level of 20, 50, 80, 100% can be set (the preset water level of this instrument is 50%). Manual water filling can be realized through the "water filling" key. With the "water supply" key, if the water level is lower than the preset water level, water can be supplied to the preset water level; If the water level has reached the preset water level, add another gear on the basis of the original water level; If the water level is full, Then stop adding "water" manually. In the process of adding water, press the "water" key to stop adding water. 3. hardware design: 3.1 design of DC power supply: 3.1.1 diagram of DC power supply: this topic can adopt an integrated three terminal voltage regulator, which can be realized as long as some peripheral components are added. Its frame diagram and circuit are as follows: 3.1.2 scheme demonstration: through block diagram analysis, this circuit is composed of four parts, and their functions are described as follows: (1) The task of power transformer is to transform the power supply voltage to an appropriate size. If the value of U2 is too large, the power consumption of the integrated three terminal regulator 7805 will be too large, the temperature will rise, and power will be wasted. On the contrary, if the value of U2 is small to a certain extent, the three terminal regulator cannot work normally and loses its voltage stabilizing effect. Therefore, the value of U2 should be appropriate, which should enable the three terminal regulator to work normally when the AC voltage is the lowest and the output current is the largest. And under the premise of normal voltage stabilization, its voltage drop is as small as possible to reduce power consumption. (2) The task of "rectification" circuit is to convert sine wave into DC voltage. Bridge rectifier circuit is generally used here, which can be composed of four diodes or rectifier bridge stack, but the parameters must be selected reasonably. (3) The first task of the filter circuit to drive an all aluminum passenger car is to turn the fully filtered waveform into a smoother DC voltage after passing through the RC filter network, reduce pulsation and improve the effect of rectification. At this time, with the development of science and technology and the improvement of industrial production requirements, the instantaneous value of the current passing through the rectifier tube is much larger than the average value, especially when the power is turned on, a considerable impulse current (i.e. charging current) passes through the rectifier tube, which should be paid attention to. (4) Voltage stabilizing circuit requires constant output