August 25th News The aluminum-to-copper battle that once caused an uproar in the air-conditioning industry was recently staged in the gas-fired water heater industry. A few days ago, some media reported that some water heaters on the market quietly "changed their minds" to reduce the cost of aluminum and copper, resulting in product safety hazards. Is the situation really as reported? Our reporter conducted an exclusive and in-depth investigation.
Focus: Aluminum substitutes for copper for questioning Recently, some media reports that gas water heater tanks using copper for many years were quietly replaced by aluminum by some manufacturers. The article said that the physical properties of aluminum are far inferior to those of copper, and it is easy to cause problems for the core components of water heaters. For example, an expert pointed out that the current water heater products, the temperature of the high temperature flue gas at the heat exchanger inlet can reach about 1000 degrees Celsius, and the melting temperature of the copper material is much higher than the melting point of pure aluminum. Some experts questioned the heat resistance and heat transfer performance of aluminum. Other experts stated that because “there has not seen any verification report on aluminum materials so farâ€, it is believed that the “Bronze Heart†water heaters are safe and reliable from decades of application, and “Aluminum†water heaters Indicators have yet to be professionally identified.
Seeing this, people can not help but feel familiar. The 2007 freezing season was particularly exciting due to the air-conditioning copper-aluminum connection.
Quality inspection department: The product has passed the relevant tests for all kinds of questions raised in the report. The related quality inspection experts gave detailed explanation to the reporter. “What we call aluminum substitute bronze is not what people think of as pure aluminum, but an aluminum alloy that incorporates titanium.†Professor Wu Guofu of the School of Urban Construction and Environmental Engineering of Chongqing University told reporters that because of the different materials added, the The melting point will change. The material used in the current product has a melting point between 650 and 700 degrees Celsius. Although there is no copper with a high melting point, it fully meets the requirements of national standards.
“The temperature of the high-temperature flue gas at the inlet of the heat exchanger reaches a temperature of 1000 degrees Celsius is only an extreme situation.†Zhang Mingwei, inspection minister of the National Gas Appliances Product Quality Supervision and Inspection Center (Foshan), told the reporter that the requirements for heat-resistant materials at 500 degrees Celsius in the national standards are actually It is much higher than the actual operating temperature of the product. Since gas water heaters work with water, their operating temperatures are mostly between 110 degrees Celsius and 260 degrees Celsius. The temperature of high-temperature flue gas may indeed reach 1000 degrees Celsius. However, this is mainly caused by dry burning due to unreasonable product design. If this happens, it will not be aluminum or copper. It will also be burned.
According to reports, in China, the gas-fired water heater heat exchanger has always been made of lead-impregnated copper materials. During the use of gas-fired water heaters, it is easy to emit a large amount of waste tobacco containing heavy metals. According to the European Union's RoHS directive, the use of lead-lead copper heat exchangers is strictly prohibited in Europe. However, in China, almost all of the flue-type products and most of the strong-row products are also used in this material, and only the high-end products use oxygen-free copper brazing technology. Since the inner and outer layers of the water tank are covered with high concentrations of lead, and the melting point of lead is only 327 degrees Celsius, if the aluminum alloy water tank is burned through, the lead-soaked copper products will not stand the test of high temperatures.
For the heat transfer performance of materials, Zhang Mingwei explained that if purely from two materials, aluminum's thermal conductivity is not as good as copper. However, this problem can be solved by product design and process improvement. He took out two pieces of water tank heat exchangers and explained to the reporter that in the immersion lead copper products, the connection of the fins in the finned tube to the water pipe, the inner wall of the combustion chamber and the coiled tubing is also done by immersion lead. There is solder and voids between the two. However, the heat conductivity of lead and air is lower than that of aluminum, which greatly affects the heat transfer rate. At present, due to the improved brazing process, the aluminum alloy heat exchanger has no gaps between the fins and the water pipes, so that the heat exchange area is greatly increased, and its thermal efficiency is naturally improved.
Competent authorities: Scientific and technological research to promote the generation of aluminum on behalf of copper Well, what is the background of the aluminum substitute copper for gas water heater water tank? In the Science and Technology Bureau of Shunde District, Foshan City, Guangdong Province, the reporter saw a contract for the Guangdong Provincial Science and Technology Plan Project - Guangdong Finance and Education (2008) No. 2, the cover of the contract notes that the project name is a new energy-saving heat exchange exchange material and system for white goods. The project plan category is a key breakthrough project in key areas of Guangdong and Hong Kong. The management unit is the Guangdong Provincial Department of Science and Technology. . In addition, there was a notice on the special fund for the production, research and research cooperation of the provincial government in 2007 (Tendering Part), Guangdong Finance (2008) No. 2. The notice indicated that key breakthrough projects in key areas of Guangdong and Hong Kong have been approved by provincial leaders according to the relevant procedures, and Issued a special fund of 4 million yuan for production, education and research in Guangdong Province and the Ministry of Education.
Guo Buqiang, deputy director of the Bureau, told the reporter that Guangdong and Hong Kong’s key breakthrough projects in the key areas were jointly decided by the Guangdong Provincial People’s Government and the Hong Kong Special Administrative Region Government. They were based on the key and common technological breakthroughs in the two pillar industries, and “new materials†and “ The six key areas such as new energy, energy conservation and resource environmental protection technologies will be jointly tendered to organize scientific and technological breakthroughs and achieve key breakthrough projects. Copper replacement of gas water heater tanks was one of them, and a tender was conducted in 2007. According to the provisions of the contract, from May 1, 2009 to October 31, 2009, experts in the industry should be invited to conduct technical, process, reliability, and safety appraisal of the product. And complete product serialization, small batch production, marketing. From November 1, 2009 to May 31, 2010, industrial mass production began. From June 1, 2010 to December 31, 2010, the acceptance of the organization's project. In fact, the development of aluminum alloy tanks was proposed in 2006. The first prototype was introduced in June 2007, and small batch production was completed in June 2008.
Guo Buqiang said that it is inconvenient to express opinions on the competitive behavior of enterprises. However, as the competent department of science and technology, he hopes that there will be a fair environment for the development and progress of science and technology. The substitution of energy-saving, emission-reducing and new materials is always a new subject of scientific and technological advancement, and aluminum-substituted copper is being carried out in various fields. This substitution is not a simple conceptual change of aluminum but a high technological content. He believes that simply negating this is not in keeping with the scientific spirit. However, he also stated that the effect of substitution still requires the data of a third-party authority to speak. Since such doubts have emerged, they will be more stringent and prudent in acceptance.
The relevant person in charge of the Guangdong Provincial Science and Technology Department project also stated that the establishment of the science and technology project was not initiated by someone clapping their heads, but was the result of an authoritative expert discussion and was in line with the objectives of the key projects for the breakthrough of key projects in Guangdong and Hong Kong.
Experts: boldly innovate and carefully seek evidence to understand that in November 2008, two gas water heaters made of aluminum-titanium alloy heat exchangers passed the inspection of the national gas appliance product quality supervision and inspection center (Foshan). The inspection concluded that: All projects comply with GB6932-2001 "Fast Gas Water Heaters for Domestic Use", GB20665-2006 "Limits and Energy Efficiency Ratings for Energy Efficiency of Household Gas Rapid Water Heaters and Gas-fired Heating Water Heaters," DB44/T402.7-2007 "Fast Heater for Domestic Gas Water Heaters" "Standard requirements, this type of test is generally qualified. In March 2009, similar products passed the inspection of the National Gas Quality Supervision and Inspection Center (Tianjin). The inspection concluded that the tested items meet the standard requirements of GB6932-2001 “Fast Water Heater for Domestic Gas Water Heater†(see Figure 1). Meanwhile, in August 2008, Chongqing University also conducted a durable life simulation test for aluminum-based copper products for 96 days (2,304 hours). The conclusion is: “The water heaters that use aluminum alloy heat exchangers have a reasonable structure and are used to simulate users 8 In the life cycle of many years, the heat exchange effect is good and the operation is safe and reliable."
Zhang Mingwei said that although the products perform well in testing, China has a vast territory and there are very big differences in the conditions of water sources and gas sources. At the same time, the water heater is also a product related to personal safety. Therefore, it will be marketed in the long term in the future. In the meantime, we must continue to correct problems that arise with a scientific and cautious attitude. However, in any case, we should encourage bold innovation in the industry, because only in this way can there be continuous progress in science and technology.
Liu Fuzhong, deputy director of the China Household Electrical Appliances Association, said that in recent years, considering the impact on the global environment, countries are increasingly demanding standards for energy-saving and environmentally friendly products, and the development and application of new technologies and new materials is to achieve the traditional home appliance products. The main means of the green upgrade transition.
In fact, for the use of alternative technologies for home appliance materials, whether manufacturers or consumers, the most concerned is whether the alternative materials can ensure that the quality of products is not affected. Liu Fuzhong believes that it cannot be attributed to the use of new technologies, new materials, and new processes. Well-known companies are very cautious about the market for new technologies and new products. Before new products leave the factory, they will conduct repeated experiments on new technologies, materials, and processes. Therefore, in general, new products can stand the test of the market. of.
The reporter learned from the National Standardization Technical Committee of Household Electrical Appliances that at present, none of the newly revised household electrical appliance product standards has defined the material of the product, but there are strict regulations on the performance indicators of the product. The purpose is to guide the enterprise to conduct Technological innovation.
However, experts also pointed out that household electrical appliance companies can't just work hard instead of burying their heads, but should promptly let consumers understand the necessity of material substitution and understand the real performance of products using alternative materials. Only in this way can we truly win the trust of consumers. To promote the smooth progress of alternative work for home appliances and materials, and to promote the rapid and benign development of China's home appliance industry . ( Source: China Consumer News )
Focus: Aluminum substitutes for copper for questioning Recently, some media reports that gas water heater tanks using copper for many years were quietly replaced by aluminum by some manufacturers. The article said that the physical properties of aluminum are far inferior to those of copper, and it is easy to cause problems for the core components of water heaters. For example, an expert pointed out that the current water heater products, the temperature of the high temperature flue gas at the heat exchanger inlet can reach about 1000 degrees Celsius, and the melting temperature of the copper material is much higher than the melting point of pure aluminum. Some experts questioned the heat resistance and heat transfer performance of aluminum. Other experts stated that because “there has not seen any verification report on aluminum materials so farâ€, it is believed that the “Bronze Heart†water heaters are safe and reliable from decades of application, and “Aluminum†water heaters Indicators have yet to be professionally identified.
Seeing this, people can not help but feel familiar. The 2007 freezing season was particularly exciting due to the air-conditioning copper-aluminum connection.
Quality inspection department: The product has passed the relevant tests for all kinds of questions raised in the report. The related quality inspection experts gave detailed explanation to the reporter. “What we call aluminum substitute bronze is not what people think of as pure aluminum, but an aluminum alloy that incorporates titanium.†Professor Wu Guofu of the School of Urban Construction and Environmental Engineering of Chongqing University told reporters that because of the different materials added, the The melting point will change. The material used in the current product has a melting point between 650 and 700 degrees Celsius. Although there is no copper with a high melting point, it fully meets the requirements of national standards.
“The temperature of the high-temperature flue gas at the inlet of the heat exchanger reaches a temperature of 1000 degrees Celsius is only an extreme situation.†Zhang Mingwei, inspection minister of the National Gas Appliances Product Quality Supervision and Inspection Center (Foshan), told the reporter that the requirements for heat-resistant materials at 500 degrees Celsius in the national standards are actually It is much higher than the actual operating temperature of the product. Since gas water heaters work with water, their operating temperatures are mostly between 110 degrees Celsius and 260 degrees Celsius. The temperature of high-temperature flue gas may indeed reach 1000 degrees Celsius. However, this is mainly caused by dry burning due to unreasonable product design. If this happens, it will not be aluminum or copper. It will also be burned.
According to reports, in China, the gas-fired water heater heat exchanger has always been made of lead-impregnated copper materials. During the use of gas-fired water heaters, it is easy to emit a large amount of waste tobacco containing heavy metals. According to the European Union's RoHS directive, the use of lead-lead copper heat exchangers is strictly prohibited in Europe. However, in China, almost all of the flue-type products and most of the strong-row products are also used in this material, and only the high-end products use oxygen-free copper brazing technology. Since the inner and outer layers of the water tank are covered with high concentrations of lead, and the melting point of lead is only 327 degrees Celsius, if the aluminum alloy water tank is burned through, the lead-soaked copper products will not stand the test of high temperatures.
For the heat transfer performance of materials, Zhang Mingwei explained that if purely from two materials, aluminum's thermal conductivity is not as good as copper. However, this problem can be solved by product design and process improvement. He took out two pieces of water tank heat exchangers and explained to the reporter that in the immersion lead copper products, the connection of the fins in the finned tube to the water pipe, the inner wall of the combustion chamber and the coiled tubing is also done by immersion lead. There is solder and voids between the two. However, the heat conductivity of lead and air is lower than that of aluminum, which greatly affects the heat transfer rate. At present, due to the improved brazing process, the aluminum alloy heat exchanger has no gaps between the fins and the water pipes, so that the heat exchange area is greatly increased, and its thermal efficiency is naturally improved.
Competent authorities: Scientific and technological research to promote the generation of aluminum on behalf of copper Well, what is the background of the aluminum substitute copper for gas water heater water tank? In the Science and Technology Bureau of Shunde District, Foshan City, Guangdong Province, the reporter saw a contract for the Guangdong Provincial Science and Technology Plan Project - Guangdong Finance and Education (2008) No. 2, the cover of the contract notes that the project name is a new energy-saving heat exchange exchange material and system for white goods. The project plan category is a key breakthrough project in key areas of Guangdong and Hong Kong. The management unit is the Guangdong Provincial Department of Science and Technology. . In addition, there was a notice on the special fund for the production, research and research cooperation of the provincial government in 2007 (Tendering Part), Guangdong Finance (2008) No. 2. The notice indicated that key breakthrough projects in key areas of Guangdong and Hong Kong have been approved by provincial leaders according to the relevant procedures, and Issued a special fund of 4 million yuan for production, education and research in Guangdong Province and the Ministry of Education.
Guo Buqiang, deputy director of the Bureau, told the reporter that Guangdong and Hong Kong’s key breakthrough projects in the key areas were jointly decided by the Guangdong Provincial People’s Government and the Hong Kong Special Administrative Region Government. They were based on the key and common technological breakthroughs in the two pillar industries, and “new materials†and “ The six key areas such as new energy, energy conservation and resource environmental protection technologies will be jointly tendered to organize scientific and technological breakthroughs and achieve key breakthrough projects. Copper replacement of gas water heater tanks was one of them, and a tender was conducted in 2007. According to the provisions of the contract, from May 1, 2009 to October 31, 2009, experts in the industry should be invited to conduct technical, process, reliability, and safety appraisal of the product. And complete product serialization, small batch production, marketing. From November 1, 2009 to May 31, 2010, industrial mass production began. From June 1, 2010 to December 31, 2010, the acceptance of the organization's project. In fact, the development of aluminum alloy tanks was proposed in 2006. The first prototype was introduced in June 2007, and small batch production was completed in June 2008.
Guo Buqiang said that it is inconvenient to express opinions on the competitive behavior of enterprises. However, as the competent department of science and technology, he hopes that there will be a fair environment for the development and progress of science and technology. The substitution of energy-saving, emission-reducing and new materials is always a new subject of scientific and technological advancement, and aluminum-substituted copper is being carried out in various fields. This substitution is not a simple conceptual change of aluminum but a high technological content. He believes that simply negating this is not in keeping with the scientific spirit. However, he also stated that the effect of substitution still requires the data of a third-party authority to speak. Since such doubts have emerged, they will be more stringent and prudent in acceptance.
The relevant person in charge of the Guangdong Provincial Science and Technology Department project also stated that the establishment of the science and technology project was not initiated by someone clapping their heads, but was the result of an authoritative expert discussion and was in line with the objectives of the key projects for the breakthrough of key projects in Guangdong and Hong Kong.
Experts: boldly innovate and carefully seek evidence to understand that in November 2008, two gas water heaters made of aluminum-titanium alloy heat exchangers passed the inspection of the national gas appliance product quality supervision and inspection center (Foshan). The inspection concluded that: All projects comply with GB6932-2001 "Fast Gas Water Heaters for Domestic Use", GB20665-2006 "Limits and Energy Efficiency Ratings for Energy Efficiency of Household Gas Rapid Water Heaters and Gas-fired Heating Water Heaters," DB44/T402.7-2007 "Fast Heater for Domestic Gas Water Heaters" "Standard requirements, this type of test is generally qualified. In March 2009, similar products passed the inspection of the National Gas Quality Supervision and Inspection Center (Tianjin). The inspection concluded that the tested items meet the standard requirements of GB6932-2001 “Fast Water Heater for Domestic Gas Water Heater†(see Figure 1). Meanwhile, in August 2008, Chongqing University also conducted a durable life simulation test for aluminum-based copper products for 96 days (2,304 hours). The conclusion is: “The water heaters that use aluminum alloy heat exchangers have a reasonable structure and are used to simulate users 8 In the life cycle of many years, the heat exchange effect is good and the operation is safe and reliable."
Zhang Mingwei said that although the products perform well in testing, China has a vast territory and there are very big differences in the conditions of water sources and gas sources. At the same time, the water heater is also a product related to personal safety. Therefore, it will be marketed in the long term in the future. In the meantime, we must continue to correct problems that arise with a scientific and cautious attitude. However, in any case, we should encourage bold innovation in the industry, because only in this way can there be continuous progress in science and technology.
Liu Fuzhong, deputy director of the China Household Electrical Appliances Association, said that in recent years, considering the impact on the global environment, countries are increasingly demanding standards for energy-saving and environmentally friendly products, and the development and application of new technologies and new materials is to achieve the traditional home appliance products. The main means of the green upgrade transition.
In fact, for the use of alternative technologies for home appliance materials, whether manufacturers or consumers, the most concerned is whether the alternative materials can ensure that the quality of products is not affected. Liu Fuzhong believes that it cannot be attributed to the use of new technologies, new materials, and new processes. Well-known companies are very cautious about the market for new technologies and new products. Before new products leave the factory, they will conduct repeated experiments on new technologies, materials, and processes. Therefore, in general, new products can stand the test of the market. of.
The reporter learned from the National Standardization Technical Committee of Household Electrical Appliances that at present, none of the newly revised household electrical appliance product standards has defined the material of the product, but there are strict regulations on the performance indicators of the product. The purpose is to guide the enterprise to conduct Technological innovation.
However, experts also pointed out that household electrical appliance companies can't just work hard instead of burying their heads, but should promptly let consumers understand the necessity of material substitution and understand the real performance of products using alternative materials. Only in this way can we truly win the trust of consumers. To promote the smooth progress of alternative work for home appliances and materials, and to promote the rapid and benign development of China's home appliance industry . ( Source: China Consumer News )