Proposal Specification for Chang'an Middle School Hot Water Renovation Project 
1、 Project Background 
The original hot water system of Chang'an Middle School adopts 355 sets of vacuum tube solar collectors with specifications of 47 * 1500 * 50 tubes/group, which have problems such as high maintenance costs, low thermal efficiency, and insufficient winter frost resistance. To enhance the stability, energy efficiency, and environmental friendliness of hot water supply, a comprehensive renovation of the system is proposed 
Dismantling the original vacuum tube system: Due to the lower frost resistance requirements of vacuum tubes in southern regions, and the higher thermal efficiency and longer lifespan (20 years) of flat solar panels, they are suitable for the climate of Dongguan. 
New equipment: Install 288 ㎡ Megaray flat solar collectors, 3 4m ³ insulated water tanks, and 1 10 horsepower air source water heater to form a dual energy complementary system of solar energy and air energy, achieving energy-saving and efficient supply. 
2、 Project objectives 
Improve energy efficiency: By combining solar energy with air energy, the comprehensive energy-saving rate target can reach over 75%. 
Ensure stable supply: meet the all-weather hot water demand of the dormitory building and avoid queuing problems during peak water usage periods. 
Reduce operation and maintenance costs: Adopt maintenance free flat panel solar energy and high durability stainless steel equipment to reduce later maintenance investment. 
Environmental protection and emission reduction: reduce reliance on traditional energy sources, in line with the national "dual carbon" policy requirements. 
3、 System Design Proposal 
1. Solar energy collection system 
Equipment selection: Select Megaray flat panel solar collectors with a total area of 288 square meters (approximately 144 pieces, 2 square meters per piece). 
Advantages: Metal tube sheet structure, high thermal efficiency (no anti freezing measures required in the south), maintenance free, 20-year lifespan. 
Layout design: Prioritize installation on roofs or sunny walls to ensure maximum natural lighting. 
Pipeline configuration: Adopting a closed loop system, copper pipes are wrapped with high-quality insulation materials to reduce heat loss. 
2. Air assisted heating system 
Equipment selection: Add one 10 horsepower air source water heater. 
Advantages: First level energy efficiency, stainless steel body corrosion-resistant, pure heat pump heating for safe design of water and electricity separation. 
Power matching: 10 horsepower hosts are matched with 3 4m ³ water tanks (total 12m ³) to meet the centralized water demand of the dormitory building and avoid energy consumption increase caused by "small horses pulling large trucks". 
3. Thermal storage and water supply system 
Insulated water tank: Equipped with three 4m ³ stainless steel insulated water tanks, the inner tank is made of food grade material and covered with a polyurethane insulation layer (thickness ≥ 50mm) to ensure a daily average temperature drop of ≤ 3 ℃. 
Water supply method: Adopting a variable frequency circulating pump, combined with a timed circulation function (such as preheating before peak water usage in the morning and evening), to reduce pipeline heat loss. 
4. Intelligent control system 
Automated operation: Prioritize the use of solar heating, automatically switch to air energy for heating when there is insufficient light, and ensure a constant water temperature (set at 55-60 ℃). 
Remote monitoring: Integrated IoT module, real-time monitoring of device operating status (such as water temperature, water level, energy consumption), abnormal alarm and support for remote debugging. 

1. 4、 Key construction steps 




2. Demolition of old system: Safely dismantle the original vacuum tube collector and associated pipelines, and recycle and dispose of waste materials. 




3. Install new equipment: 




4. Flat panel solar energy: fixed bracket installation on the roof, with an optimized tilt angle according to the latitude of Dongguan (about 23 °). 




5. Air source host: placed in a well ventilated area (such as a living balcony) to avoid obstruction and affect heat transfer efficiency. 




6. Insulated water tank: Located near the solar collector to reduce pipeline length. 




7. System debugging: 




8. Test the solar energy collection efficiency, air heating speed, and water tank insulation performance. 




9. Calibrate intelligent control parameters to ensure seamless switching between dual energy sources. 




10. User training: Provide training to school management personnel on system operation, daily maintenance, and troubleshooting. 




11. 5、 Energy saving and environmental protection measures 




12. Energy complementarity: Solar energy meets over 80% of demand on sunny days, supplemented by air energy on rainy days, with a comprehensive energy efficiency ratio (COP) of over 4.0. 




13. Variable frequency technology: The water pump and air compressor adopt variable frequency control to adjust power as needed and reduce standby energy consumption. 




14. Environmentally friendly materials: The equipment uses stainless steel and environmentally friendly refrigerants (such as R410A) to reduce pollution and carbon emissions. 




15. 6、 Operations and Security Assurance 




16. Regular maintenance: 




17. Clean the dust on the surface of the flat solar panel every quarter and check the cleanliness of the fins of the air evaporator. 




18. Check the scale inside the water tank every year, and if necessary, perform acid washing to remove the scale. 




19. Safety design: 




20. Water and electricity separation structure, equipped with leakage protection, antifreeze protection, and over temperature alarm function. 




21. Install fireproof materials on the insulation layer of the pipeline to avoid high temperature hazards. 




22. 7、 Economic Benefit Analysis 




23. Initial investment: Approximately 1 million yuan (including equipment procurement, installation, and dismantling costs). 




24. Energy saving benefits: 




25. Annual electricity savings of approximately 300000 yuan (compared to the original pure electric heating system). 




26. The equipment has a lifespan of 20 years and an investment payback period of approximately 3-4 years. 




27. Social benefits: Reduce carbon emissions by about 120 tons annually, helping to promote the green transformation of campuses. 




28. 8、 Project acceptance criteria 




29. Performance acceptance: Tested continuously for 7 days, with an average daily hot water supply of ≥ 12m ³ and a stable water temperature of 55 ± 5 ℃. 




30. Safety acceptance: Through third-party electrical safety testing, there are no leaks or fault alarms. 




31. Document handover: Provide equipment manuals, warranty cards, and system operation manuals. 




32. Note: This plan combines the climate characteristics of Dongguan with the needs of the school, with solar energy as the main source and air energy as a supplement, taking into account both energy efficiency and economy. Specific details need to be optimized and adjusted based on on-site survey data.