Abstract: Saving energy and protecting the environment, developing and utilizing clean, environmentally friendly renewable energy, optimizing energy structure, and developing a low-carbon economy are important ways for China to achieve sustainable development. Solar energy, with its rich reserves, safety, reliability, clean and pollution-free advantages, has become one of the important choices for countries in the world to cope with energy crisis, environmental degradation and sustainable development. The use of Delta PLC to control the solar hot water system can realize system automation, improve system operation stability and reduce operating costs. This system has strong practicability, low installation and operation cost and strong promotion. Keywords: Delta Energy Solar Power PLC Abstract: Energy conservation, environmental protection, development and utilization of clean, green, renewable energy, optimizing energy structure, development of low-carbon economy is an important way to achieve sustainable development.Solar with its abundant, safe, reliable, clean and pollution And other advantages, become the world's response to the energy crisis, environmental degradation and achieve sustainable development of the important options. Delta PLC on the use of solar hot water systems to control, the system can achieve automation,improve system stability, reduce operating costs . This system is practical, low cost of installation and operation, with strong promotional. Key words: Delta Energy Solar PLC 1 Introduction The system is widely used and is suitable for occasions that require hot water supply, such as office buildings, hotel bathing, etc., and is particularly suitable for areas with rich solar energy resources. The control system uses Delta DVP40ES2 PLC, DVP04PT-E2, DVP04AD-E2, and Delta HMI B07S515. The system has stable working performance and high degree of automation. In particular, the design of constant temperature effluent saves a lot of water resources. The design of the heat collection cycle makes the solar hot water efficiently circulate into the water tank. The addition of the auxiliary heat source solves the problem of insufficient solar energy resources. Under the hot water supply. 2 system composition Delta series man-machine interface, Delta ES2 series CPU, Delta PT-E2 series temperature control module, Delta AD-E2 series analog transfer digital module, solar collector, heating wire (or air source heat pump, etc.) Auxiliary heat source), insulation tank, bath control pump, heat collection circulation pump, solenoid valve, temperature sensor, liquid level sensor, power transmitter, etc., as shown in Fig. 1. 3 system working principle and cycle process (1) Automatic Sheung Shui The water tank contains a level sensor p. When the water in the tank is lower than a certain value (20%), the automatic replenishment valve is powered on. The water tank automatically replenish water. When the water level reaches the set value (90%), the automatic replenishment valve is powered off and automatic replenishment stops. . (2) Heat collection cycle When the collector water outlet water temperature (outlet installation temperature sensor) is higher than the water temperature in the tank, reach the PLC set the start temperature difference (6-10 degrees Celsius), the collector circulating pump starts; the hot water tank into the low-temperature water In the vacuum tube collector set, the relatively high temperature water in the collector is circulated to the hot water tank to increase the temperature of the water in the tank. When the temperature difference decreases to the system setting stop temperature difference (1-3 degrees Celsius), the circulation pump stops and the heat collection cycle stops. In this way, the heat is gradually transferred to the water tank so that the temperature of the water in the water tank gradually increases until it reaches the bathing temperature. (3) thermostatic water discharge The constant temperature return water circulation is mainly for indoor hot water baths, in order to ensure that there is hot water when opening the nozzle valve, and at the same time to reduce the waste of invalid cold water, hot water return pipeline must be installed, take the pipeline cycle measures . The circulation of the pipeline adopts the constant temperature circulation method, and a temperature detection sensor and a circulation pump are installed in an appropriate position in the indoor hot water return pipeline, and a temperature range is set to control the operation of the pump. When the water temperature in the pipeline is lower than the set value, the bath circulation pump is started, and the low-temperature hot water in the pipeline is driven into the heat preservation water tank. When the water temperature reaches a set value, the pipeline circulation pump stops operating. (4) temperature control When the water temperature in the water tank is lower than a certain value, the collector cannot reach the temperature of the bathing hot water. At this time, the electric heating in the water tank or other auxiliary heat source (air source heat pump) is turned on to ensure that it can be guaranteed under any weather conditions. Hot water supply is an important factor. (5) Winter freeze protection cycle The outdoor pipe (between the holding tank and the collector) may be frozen in cold winter, so it must have the function of antifreeze circulation; when the collector temperature (detecting sensor temperature) is lower than a certain value (2-5 degrees Celsius), Start the heat-collecting circulating pump and heat the hot water in the heat-retaining water tank into the heat collector to prevent the pipes from freezing. 4 Electrical Control System Design The system upper computer chooses HMI b7s515 model touch screen to realize the visual monitoring and control of the system operation. The lower computer adopts Delta series PLC, the host CPU selects DVP40ES2, the temperature module selects 04PT-E2, and the AD module selects 04AD-E2. The expansion module can also incorporate power transmitters to monitor the power of solenoid valves, circulation pumps, and auxiliary heat sources, as shown in Figure 2. Figure 2 System Hardware Framework (1) The temperature-related signal detected by the temperature sensor is converted into a digital value by the PT module and then transferred back to the CPU of the PLC. The status of the PLC is reflected on the touch screen to realize real-time monitoring of the data, as shown in FIG. 3 . Figure 3 External wiring diagram of temperature sensor PT100 and DVP04PT module (2) After the tank level sensor detects the electrical signal, after the level transmitter converts the electrical signal to the standard current signal of 4-20mA, it is converted into a digital signal by the AD module and sent back to the PLC. The PLC sets the value according to the set value. To make a judgment, control the opening and closing of the tank solenoid valve, as shown in Figure 4. Figure 4 External Wiring Diagram of Level Transmitter and 04AD-E2 Module In addition, the measurement temperature of each temperature sensor directly represents the temperature of each component to control the operation of the system. Therefore, the installation position of the temperature sensor is extremely important. The temperature at which the temperature sensor is installed must be representative of the average temperature of the part being measured. Water Based Laminating Adhesive Water Based Laminating Adhesive,Water Based Adhesive,Laminating Chemical,Water Based Laminating Machine Zhejiang Joya Polymer Technology Co.,Ltd , https://www.joyapolymer.com