Solar Water Heating Collector

I. Product Introduction

The flat-panel solar collector for hot water projects (Solar Water Heating Collector) is specially designed for large-scale hot water projects. It is the core component of centralized heating systems in hotels, schools, factories, hospitals, swimming pools, etc. This product uses laser-welded flat-panel collectors and combines with highly selective heat-absorbing coatings, featuring high heat collection efficiency, strong pressure-bearing capacity, and long service life. It is the ideal choice for commercial and industrial-grade solar hot water projects. 

The flat plate collector is equipped with a high-strength aluminum alloy frame and a low iron tempered glass cover. The interior consists of a full copper flow channel and an absorber plate. Laser welding technology perfectly fuses the absorber plate and the flow channel, with uniform weld points and extremely low thermal resistance. The heat transfer efficiency is over 15% higher than that of traditional ultrasonic welding. The weld seam is corrosion-resistant and has no leakage risk. The absorber plate is covered with a blue titanium film (or black chrome) highly selective coating, with an absorption rate of ≥ 95% and an emissivity of ≤ 5%. It still efficiently collects heat under weak light conditions. The appearance of the collector is smooth and modern, enabling solar energy integration with buildings (BIPV/T). It has passed international certifications such as Solar Keymark and CE. 

II. Technical Parameter Table

Product Model SWH-2.0 / SWH-2.5 (Single area 2.0/2.5 m²)

Applicable Scenarios Hotels, schools, factories, hospitals, swimming pools, regional heating 

Note : ① Rated efficiency: The total irradiance on the daylighting surface of the collector is 1000W/㎡, and the temperature difference between the average temperature of the collector and the ambient air temperature is 50°C. Calculate the efficiency value of the solar collector according to the instantaneous efficiency equation of the collector's daylighting area.

② Rated power: The total irradiance of the collector lighting plane is 1000w/㎡, and the collector power when the temperature difference between the average collector temperature and the ambient air temperature is 50 ° C is equal to the product of the rated efficiency and the day lighting area and 1000W/㎡.

III. Working Principle

The flat-panel solar collector operates based on the principles of the greenhouse effect and heat conduction: 

1. Solar thermal conversion: Sunlight passes through the low iron tempered glass and is absorbed by the heat-absorbing coating on the blue titanium film. The coating efficiently converts solar radiation energy into thermal energy, heating the heat-absorbing panel. 

2. Heat Conduction: Heat is rapidly transferred through the low thermal resistance path formed by laser welding to the copper channels directly attached to the heat-absorbing plate. The antifreeze or water within the channels is heated and its temperature rises. 

3. Cyclic Heating: The heated medium is transported to the hot water storage tank or directly supplied to the end users through a circulation pump. Multiple collectors can be connected in series or in parallel to form a collector array, meeting the demand for large water volume. 

4. Thermal insulation and anti-freezing: The bottom and periphery of the collector are filled with glass wool insulation layer to reduce heat loss; combined with antifreeze fluid and low-temperature circulation protection, it can operate in cold regions. 

Laser welding ensures that the heat-absorbing plate and the flow channel have a "surface contact" rather than a "point contact", resulting in higher heat transfer efficiency and better overall heat collection performance of the entire system. 

IV. Product Advantages

1. Laser welding technology, efficient heat transfer

By using laser welding technology, the fusion area between the heat-absorbing plate and the flow channel is large, and the thermal resistance is low. The heat transfer efficiency is 15% higher than that of ultrasonic welding. It does not delaminate over a long period of use and ensures stable output for 20 years. 

2. Blue Titanium Coating, Efficient in Low Light Conditions

The highly selective Blue Titanium coating has an absorption rate of ≥ 95% and an emissivity of ≤ 5%. It remains highly efficient in collecting heat even on cloudy days, in the morning, and in the evening, and its daily efficiency is superior. 

3. All-copper flow channels, resistant to pressure and corrosion

The internal flow channels of the collector are all made of copper, while the heat-absorbing plate is made of aluminum. It can withstand a pressure of 0.6 MPa, is corrosion-resistant and frost-proof, and is suitable for closed-loop systems. The service life can last for over 15 years. 

4. Aluminum alloy frame + tempered glass, sturdy and durable

The anodized aluminum alloy frame is corrosion-resistant, while the low iron tempered glass has high light transmittance and is resistant to hail impact, suitable for various harsh weather conditions. 

5. Modular design, flexible engineering configuration

Each individual collector can be freely combined to form a collector array, ranging from several square meters to several thousand square meters, meeting the water heating needs of large-scale projects such as hotels, schools, and factories. 

6. International Certification, No Worries about Export

The product has obtained certifications such as Solar Keymark and CE, meeting the standards of the European Union and international organizations, which helps engineering companies to undertake overseas projects. 

V. Factory Advantages

Our company has been dedicated to the research and manufacturing of flat solar collectors for 15 years. We possess a fully automated laser welding production line and are a high-quality overseas OEM/ODM supplier. 

1. International certifications: ISO9001, ISO14001, Solar Keymark, CE. The products are exported to over 50 countries in Europe, Africa, the Middle East, Southeast Asia, and South America. 

2. Laser welding expertise: We have introduced German technology for laser welding equipment, with a welding speed of 30m/min. The weld points are uniform and free from oxidation, and the weld seam has high tensile strength. 

3. Core production: We have an absorption coating spraying line, a laser welding line, and an assembly line. The key processes are all independently completed, ensuring controllable quality. 

4. Customization capability: Supports OEM customization of collector size, absorber coating type (blue film/black film), frame color, etc. 

5. Engineering Support: Offer design of collector arrays, pipeline calculations, installation guidance and technical training, providing a complete set of services for the engineering contractors. 

6. After-sales Guarantee: The product is covered by a 5-year warranty. An English manual, CAD drawings, and remote technical support are provided. 

VI. Installation Precautions

1. Orientation and Angle: Facing south (northward in the Southern Hemisphere), with an angle of ±10° from the local latitude. This ensures the maximum reception of sunlight throughout the year. 

2. Array spacing: The spacing between the front and rear collectors should ensure unobstructed visibility from 9:00 to 15:00 on the winter solstice. Generally, this is calculated as 2 to 3 times the height of the collector. 

3. Pipeline connection: A single-loop parallel design is adopted to ensure the balanced flow of each collector. The circulation pipeline needs to be insulated (≥ 30mm), and an external heating tape is installed for anti-freezing purposes outdoors. 

4. Anti-freezing measures: In cold regions, antifreeze (propylene glycol) must be used as the heat transfer medium, and a low-temperature circulation protection system must be installed. 

5. Installation method: Use aluminum alloy or stainless steel brackets, which are firmly connected to the roof structure, with a wind resistance rating of ≥ 12 levels. 

6. Exhaust and Pressure Relief: An automatic exhaust valve is installed at the highest point of the system, and a drain valve is set at the lowest point to prevent air blockage and facilitate maintenance drainage. 

VII. Application Cases

1. Hotel: A 160m² heat collection array was formed by using 80 laser-welded 2.0m² flat collectors, combined with a 3000L water tank. This design provided hot water for 80 guest rooms, resulting in an annual gas cost savings of approximately 12,000 Australian dollars. 

2. School: 120 solar collectors provide hot water for showering for 2,000 students. They complement the gas boiler. In summer, it is completely free of charge. In winter, it saves 45% of energy. 

3. Factory: 50 solar collectors + air-source heat pumps are used to supply water to the dormitories for 500 employees. The annual operating cost is 70% lower than that of pure electric heating. 

4. Swimming Pool: 30 heat collectors are used to maintain the constant temperature of the outdoor swimming pool, extending the swimming season by 4 months, and the investment payback period is 2 years. 

VIII. Development Trends

1. Popularization of Laser Welding: Due to its high heat transfer efficiency and stable quality, laser welding is gradually replacing ultrasonic welding and has become the mainstream process for high-end flat plate solar collectors. 

2. Large-scale district heating: A combination of flat plate collectors and seasonal energy storage is employed in district heating systems, which is rapidly developing in Europe and northern China. 

3. Building Integrated Photovoltaics (BIPV/T): Flat plate collectors are integrated with photovoltaic modules and building facades, shifting from an "add-on" approach to a "construction-based" model. 

4. Intelligent Monitoring: The collector array is equipped with flow, temperature and pressure sensors, which are connected to the Internet of Things to enable remote operation and fault early warning. 

5. Efficient Coating: The new selective heat-absorbing coating (such as titanium nitride) has an absorption rate of over 96%, with an emissivity of less than 4%, further enhancing efficiency. 

6. Multi-functional complementarity: Solar collectors + heat pumps + heat storage tanks have become the standard configuration for large-scale projects, achieving the lowest operating costs throughout the year. 

Summary: The Flat Plate Solar Collector Water Heating Project (Solar Water Heating Collector) features core advantages such as laser welding technology, high-efficiency coating with blue titanium film, and all-copper flow channels. It provides reliable and efficient heat collection solutions for large-scale hot water projects worldwide. We sincerely invite overseas distributors, distributors, and engineering contractors to join hands and collaborate! 

Contact us immediately to obtain the quotation, engineering plan and channel cooperation policy for the laser welding flat plate collector!  Website: www.btesolar.com