"Oops, it's cloudy again, and the water definitely won't be hot!" Aunt Li looked at the solar water heater on the roof and said helplessly.
Uncle Wang, a neighbor, comforted her: "It's okay, when the sun comes out, hot water will be available soon." Besides, we use solar energy, which not only saves electricity and coal, but also protects the environment!"
This is a scene that used to be common on the streets of China. Solar water heaters, with their environmental protection and energy-saving characteristics, once shined on the roofs of thousands of households. That piece of "sapphire" carries people's yearning for a better life.
But in recent years, these "sapphires" seem to have faded into obscurity. How is it that a once thriving industry has gradually declined?
Solar energy, which was once "all the rage".
What exactly is the magic of the solar water heater, the glittering "sapphire" on this roof? How does it convert the sun's light and heat into hot water that we can use?
Actually, the working principle of a solar water heater is not mysterious, it is mainly composed of three parts: a collector, a tank, and a bracket. The collector is the "heart" of a solar water heater, generally a flat plate or vacuum tube type, which is responsible for absorbing solar radiation and transferring heat to the water.
After the water is heated in the collector, it flows down the pipe into a well-insulated tank and is ready for our use.
As you can imagine, the collector is like a person who is hot under the sun, and the cold water is like a basin of water poured on him, which is instantly warmed by his body temperature.
However, the collector absorbs the heat of solar radiation, rather than relying on metabolism to produce heat like a human being.
The biggest "magic" of a solar water heater is that the energy it uses is inexhaustible. Solar energy is a renewable energy source, and as long as the sun is still around, we don't have to worry about running out of energy. Compared to electric water heaters or gas water heaters, solar water heaters consume almost no additional energy during use, so they are very environmentally friendly and energy-saving.
Data shows that a household solar water heater can produce an average of about 150 liters of hot water at 60 degrees Celsius per day, which can save more than 1,500 kilowatt-hours of electricity and reduce carbon dioxide emissions by more than 1.5 tons for a family of four in a year. That's the equivalent of planting 85 trees!
You see, using a solar water heater is not only saving money for the family, but also "saving money" for the earth.
In addition to environmental protection and energy saving, solar water heaters also have the advantages of safety and reliability, long service life, and simple maintenance. Since no electricity or gas is used, the solar water heater has no potential safety hazards of electricity leakage or gas poisoning, making it ideal for families with elderly people and children.
A high-quality solar water heater can be used for 15-20 years under normal use and maintenance, which is equivalent to accompanying us for most of our lives. Even if maintenance is occasionally required, a simple cleaning and inspection of the collector and tank is all that is required.
This is where the "magic" of solar water heaters lies. It uses natural solar energy to provide us with environmentally friendly, safe and economical hot water through simple and ingenious principles.
From glory to loneliness
The development of solar water heaters in China is like a business epic of ups and downs. It grew from scratch, from small to large, and once became a leader in solar energy utilization in China and even in the world.
But after the boom, it fell into a trough, in which there was the joy of technological progress and the melancholy of market change.
As early as the end of the 70s of the last century, researchers from the Institute of Mechanics of the Chinese Academy of Sciences began to research solar water heaters. In 1978, they developed the first prototype of flat panel solar water heater, which opened the curtain on the development of solar water heaters in China.
Since then, this technology has begun to be popularized and applied throughout the country, especially in rural areas and suburbs of towns.
In the 90s, with the advent of vacuum tube solar water heaters, the industry ushered in a new technological revolution. Compared with the flat plate type, the vacuum tube type water heater has higher heat collection efficiency and better thermal insulation performance, and soon occupies a dominant position in the market.
During this period, a large number of solar water heater companies have sprung up, and the scale of the industry has been expanding.
In the 21st century, with the strong support of national policies, the solar water heater industry has ushered in a golden period of development. From 2000 to 2010, the average annual growth rate of the total production of solar water heaters in mainland China was as high as more than 25%.
By around 2010, China had become the world's largest producer and application of solar water heaters, accounting for about 60% of the global total. The pieces of "sapphires" spread all over China's urban and rural areas, becoming a unique landscape and a beautiful business card of China's solar industry.
But with the rapid expansion of the industry, problems have gradually begun to emerge.
On the one hand, some unscrupulous manufacturers cut corners in pursuit of profits, resulting in uneven product quality. Installation and after-sales service cannot keep up with the growth of product sales, and consumer complaints are increasing day by day; On the other hand, with the acceleration of urbanization, more and more high-rise buildings, and less and less space for rooftop installation, the market demand for solar water heaters has begun to shrink.
At the same time, competitors such as electric water heaters and gas water heaters are also developing rapidly, constantly eating into the market share of solar water heaters. Especially with the reduction of electricity prices and the advancement of electric water heater technology, the cost-effective advantage of solar water heaters is no longer obvious.
According to statistics, from 2015 to 2019, the output of solar water heaters in mainland China fell from 45 million square meters to about 35 million square meters, and the market size shrank significantly. Some small and medium-sized enterprises have closed down one after another, and the industry reshuffle has intensified.
As a result, some far-sighted enterprises have begun to transform and upgrade, and open up new market space through technological innovation and model innovation. Among them, there is the future of the solar water heater industry, as well as the hope of the Chinese industry.
Fall into the shade
As mentioned above, the acceleration of urbanization and the increase in high-rise buildings are important reasons for the shrinkage of the solar water heater market. Previously, solar water heaters were mainly installed on the roofs of detached houses or low-rise buildings.
But with the advancement of urbanization, more and more people are living in high-rise buildings. These buildings have limited roof space, making it difficult to meet the needs of all residents to install solar water heaters. Even if it is installed, it may affect the heat collection effect due to the occlusion of the building's shadows.
Secondly, the rapid development of competitors such as electric water heaters and gas water heaters is also constantly encroaching on the market for solar water heaters.
In particular, with the deepening of the reform of the power system, the price of residential electricity is on a downward trend. Coupled with the advancement of electric water heater technology and the improvement of convenience of use, many consumers have begun to turn to electric water heaters.
In contrast, solar water heaters are subject to weather conditions, the hot water supply is not stable enough, and the convenience of use is relatively poor.
In addition, some consumers are not satisfied with the product quality and after-sales service of solar water heaters in the process of use, which also affects their willingness to continue to choose solar water heaters.
With the rapid expansion of the industry, some unscrupulous manufacturers cut corners in product quality in pursuit of profits, resulting in frequent problems such as water leakage and scaling. At the same time, many manufacturers do not pay enough attention to after-sales service, and the installation and maintenance are not timely, which further aggravates consumer dissatisfaction.
In addition, the change of consumption concept has also affected the market of solar water heaters to a certain extent. With the acceleration of the pace of life, there is an increasing demand for "instantaneous" water heaters.
In contrast, solar water heaters need to boil the water well in advance according to the weather conditions, which is not convenient enough to use. Some young consumers even think that solar water heaters are synonymous with "earth" and "low".
Based on the above factors, solar water heaters are gradually fading out of the market, which seems to have become an inevitable trend. But does that mean that solar water heaters are coming to an end? Not really.
Just like any mature industry, the solar water heater industry also needs to find a turnaround in the crisis and seek new life in the midst of change.
This requires enterprises to innovate in technology, models, services, etc., the government needs to support in policy guidance and industry norms, and the whole society needs to reach a consensus on energy conservation and environmental protection awareness.