Project overview 
Dongguan Technician College Vocational Education City Campus has decided to implement a solar hot water project to improve the living quality of the staff turnover dormitory building and meet the daily hot water needs of the faculty. The project aims to create an energy-saving, efficient, and stable hot water supply system, providing comfortable and convenient living conditions for the faculty. 
Equipment Selection 

1. Solar collector: Choose 300 square meters of Megaray brand solar energy. As a well-known domestic solar energy R&D and production enterprise, Megaray has profound technical accumulation and rich industry experience. The flat plate collector adopts an advanced fully enclosed breathing system without rivets, which eliminates water vapor and fog, greatly improving performance. The absorption rate of the collector film layer is as high as 97%, the heating performance reaches 34.49 ℃, the insulation performance is 1.98 ℃, and the total heat loss coefficient is 4.8W/cm2. All key indicators are at the leading level in the industry, ensuring efficient collection of solar energy and conversion into heat energy. 
2. Heat pump units: equipped with 4 sets of 10P Megaray brand heat pump units. The heat pump unit adopts a full DC frequency conversion+EVI jet enthalpy increasing low-temperature heat pump compressor, which has excellent energy-saving and high-efficiency heating capabilities. It has low noise during operation and low impact on the power grid during low-frequency start-up. It uses R410A environmentally friendly refrigerant, which is green and environmentally friendly; It can operate in a wide frequency range, with smooth start-up and shutdown, reducing the loss of equipment caused by frequent start-up and shutdown. It has strong heating and minimal heat attenuation. In addition, the unit also has intelligent defrosting function, which can accurately defrost according to the actual situation, and supports intelligent IoT. Through remote control, the operation and monitoring of the equipment can be achieved, which is convenient for management and maintenance. 
System working principle 
1. Solar priority mode: When there is sufficient sunlight, the solar collector efficiently absorbs solar energy, transfers heat to the medium, and the medium circulates to heat the water and store it in the insulated water tank. At this time, the heat pump unit is in standby mode, fully utilizing the free solar energy resources and reducing energy consumption. 
2. Heat pump auxiliary mode: When encountering rainy weather, insufficient sunlight, or high water consumption resulting in insufficient solar heat supply, the heat pump unit will automatically start. Using the principle of reverse Carnot cycle, the compressor works on the refrigerant to absorb heat from the air and transfer it to the water in the water tank, continuously ensuring the supply of hot water and ensuring the stable operation of the system