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Established in 1995, Beijing Sunda Solar Energy Technology Co., Ltd. is a leading Chinese manufacturer of solar vacuum tube, solar collector, solar water heater. Owing to their premium quality and competitive prices, these products have been well sold to more than 80 countries and regions, such as Germany, Italy, Spain, British, France, Sweden, Bulgaria, Romania, Russia, Malta, the United States, Canada, Mexico, Chile, Korea, Singapore, Malaysia, Lebanon, Jordan, U.A.E, Australia, South Africa, Hong Kong, etc. There are agents in more than 50 countries and regions.

Solar Vacuum Tube
The solar vacuum tube is suitable for OEM manufacturers and for a great number of applications. Absorber and heat pipe are installed in a borosilicate vacuum glass tube which features high stability. Furthermore, the absorber is coated with the aluminum nitride selective coating for high absorptance, low emittance and highest efficiency even on cloudy days. As compared with the widely used all glass vacuum tubes, our heat pipe and direct flow solar vacuum tubes feature advanced manufacturing and application technologies, wide applications, good adaptability to large scale projects, high safety and sanitary, high heat efficiency, high stability, quality and cost effectiveness, long operation life, etc. These features can be illustrated as follows.

1. Advanced Manufacturing and Application Technologies
The glass and metal are connected with each other using the patent thermo-compression sealing technology. The absorber is made of metal and in high vacuum. Furthermore, the vacuum technology is introduced from the Daimler-Benz Aerospace. The heat pipe vacuum tube series adopts the phase transition heat transfer and unidirectional heat conduction by the diode effect. The direct flow type works without the constraints of the installation angle. It can be well installed on the façades of the building for exquisite appearance and high practicality.

2. Wider Application
Having gentle efficiency curves, vacuum tube products are less influenced by outside environments. They can be extensively used in various places, especially for alpine areas. Additionally, the coldest place where these products have been used is Zhongshan Station, Antarctica.

The heat pipe and direct flow vacuum tubes can also be applied to systems requiring medium or high temperatures, such as the solar air conditioning system. Our company and our agents and dealers have successfully installed the air conditioning systems with vacuum tubes, with 8 in Korea, 3 in America, 2 in Germany, 2 in China , 1 in Malaysia 1 in Japan and 1 in India till 2010. Additionally, these systems have won good reputation among our customers. Concurrently, we have developed (Receiver tube) able to produce the temperature over 450 ℃. Thus, such tubes can supply heat for the highly efficient absorption chillers to constitute the solar air conditioning system as well as can be used for parabolic trough concentrating solar thermal power generation system.

3. Good Adaptability to Large Scale Projects
Owing to the "dry connection", all the solar vacuum tubes are easy to install and maintain, especially being suitable for the large scale pressurized system. So in case of damage, they can be replaced with ease without the need to shut off the whole system, which meanwhile helps save a lot of water.

4. Safety and Sanitary
The shell of the solar vacuum tube is made of high strength borosilicate glass with a length of 2m and the thickness of over 2.5mm. This solar vacuum tube has strong impact resistance. The glass and metal are connected together using the patent thermo-compression sealing technology, with the tensile strength over 300kg and higher mechanical properties. The parts in contact with water are all made of copper, thus having no influence on the water quality. There is no water in the heat pipe vacuum tube, so the dirt in the water will not be deposited within the tube. The direct flow vacuum tube adopts antifreeze as the heat transfer medium, which brings convenience for pressurized closed circulation.

5. High Heat Efficiency
The metal absorber is coated with selective coating by the magnetron sputtering technology, which brings higher solar irradiation absorbance and very low emittance. Moreover, the high vacuum technology also helps effectively prevent the heat loss. Furthermore, the heat efficiency attenuates little under high vacuum.

6. Long Operation Life
Our solar vacuum tubes are long-lasting even under very rugged weather conditions, owing to its high quality.

7. High Stability, Quality and Cost Effectiveness
Our products are made using the glass-metal thermo-compression sealing technology with the metal being coated and phase-change heat pipes or copper pipes used to transfer the heat. So far, there are other enterprises producing the products with the similar structure with our products at home and abroad. Compared with products provided by our domestic counterparts, our products are developed earlier than their rivals and have better quality, better stability and longer operation life. As for those products supplied by our foreign counterparts, our products feature higher cost effectiveness.

Solar Collector
Our solar collector is designed with not only exquisite appearance but also high efficiencies in various applications. In this product, the heat pipe tubes are not in direct contact with the water circle, so they are easy to be replaced or added. Requiring less space, this product can be mounted in places with limited available space but can still supply high temperature water. It is also an ideal solution to both single unit installation and large scale installation for heating or air conditioning projects.

Solar Water Heater
The solar water heater we supply here is available in 5 types, including heat pipe type, flat plate type, evacuated tube type, flat plate split type as well as heat pipe split type. Actually, the solar water heating system can also be divided into integral type and split type. As for the former type, the solar collector and the hot water tank are integrated into one unit. By contrast, in the latter type, these two components are placed separately. These products are well equipped with heat pipe vacuum tube, flat plate collector or all-glass vacuum tube. This solar water heating system is able to supply 70% of the required water heating energy throughout the year and give 100% during the summer.

Over 17 years of development, we have given the first priority to the product quality. At the very beginning of our establishment, our company has won the ISO9001 international quality system certification. Now, we have established a complete and sound quality assurance system to have an overall monitoring of the whole production process from the selection of raw materials through to the inspection of final products. We also have a complete property testing system and management system.

Our company has advanced production equipment, such as high frequency welder, magnetron sputtering coating machine, thermo-compression sealing , rotating exhaust station, etc. as well as testing equipment, including spectrophotometer, emissive measuring instrument, salt spray test machine, etc. There is an IQC inspection team which carries out rigorous tests of the raw materials using advanced testing equipment. There are 7 examination divisions, 1 testing center and 13 monitoring points. All the products are required to go through thousands of tests to make sure the good quality. Only the qualified products can be delivered to our customers.