The sun not only brings heat to humanity, but also provides food. Plants can only grow, flower and bear fruit when exposed to sunlight. Therefore, various foods are actually stores of solar energy. When people usually eat vegetables and fruits, they consume solar energy. You see how close the relationship is between sunlight and human beings. Human beings cannot survive without sunlight.
Since the sun is so important to humans, how humans use solar energy has become an important research topic.
A pot of water placed directly in the sun will only heat it, but will never boil because the temperature is not sufficient. But if the kettle is placed in a sealed glass box so that the heat "can only enterbut not go out,” then the water can be “dried in the sun” until it boils. The world's first solar energy harvesting device was a glass box called a "hot box".
It was 1770. Someone made five glass boxes of different sizes and stacked them on top of each other. The space between each box was only a few centimeters. When exposing this set of glass boxes to the sun, it was found that the highest temperature was between the fourth and fifth boxes (counting from the outside to the inside), reaching 88°C. Later, someone used good insulating materials to make the bottom of the box and painted it black. As a result, the maximum temperature rose to 120°C. Using this “hot box” to boil water quickly became a sensation.
What is the secret of this “hot box”? Mainly on the "glass". It turns out that the quart glassz has a strange characteristic: it only lets shorter wavelength radiation through, while blocking long wave radiation. The wavelength of sunlight is shorter and can penetrate unimpeded into the box through the glass. Once the material (such as air or water) in the glass box absorbs energy from the sun, the temperature rises and heat is radiated. Since this thermal radiation has a longer wavelength and cannot escape from the box through the glass, the temperature inside the glass box gradually increases.
A solar cooker (see image on previous page) is also a device that uses solar energy. It relies on using lenses or reflectors to gather sunlight.
The cold beds and greenhouses that are common in the north are as warm as spring indoors, which is alsot due to the glass.
Nowadays, we are constantly seeing buildings using solar energy that are both beautiful and practical. There is a sort of passive solar room. The sunny side wall is black, and a sealed glass frame is installed outside the wall to form a channel-shaped space between it and the exterior wall. The sun heats the air in the passage, and the warm air rises and enters the room through the upper valve. Cold air from the room can enter the passage through the bottom vent for heating. This cycle continues and the ambient temperature continues to rise. . In summer, as long as the upper shutter is open to the outside, hot air circulates outside. This allows cooler air from the north of the house to continue entering the room, replacing the warm air escaping. the ambient temperature also drops. Such a veranda, as long as it has good insulation materials and reasonable design, canhave the effect of keeping warm in winter and cool in summer.
Some solar water heater collector boxes have similar principles and structures. Most of them are installed on the roof, adding splendor to modern buildings.
Recently, a new type of glass tile has been developed abroad, and its main raw material is silicon. This type of tile itself is a solar energy storage device. It can generate power not only in the sun, but also in rainy days, which can be used for indoor lighting.
My house has a tiled roof, which was installed by Shanghai Lipu Energy. During installation, you lift a few tiles, install hooks under the tiles, then attach the brackets and install the panels. The roof is not damaged and the tiles are not broken. A friend's house also installed a solar power generation system.His house has a flat concrete roof and the supports are attached to poured cement pillars, which will not damage the roof.