New type of solar equipment can be heated and cooled

New type of solar equipment can be heated and cooled

A recent study by Chinese and American scientists published in the American "Joule" magazine shows that they have developed a new type of equipment that can use the principle of radiant cooling while heating by solar energy. Installing such equipment on the roof helps to save energy.

　　Radiant refrigeration uses the natural phenomenon that objects on the earth dissipate heat to extremely cold outer space through thermal radiation. Usually the earth's atmosphere hinders heat radiation, and the air wraps around us like a "blanket", so the effect of radiant cooling is not obvious. However, the researchers found that there are "holes" in the air "blanket". Infrared radiation of a specific band can pass through the "holes" and take away heat. The advantage of this cooling method is that it does not consume electricity.

　　On the other hand, solar panels heated by solar energy are common. The team of Professor Shanhui Fan from Stanford University and Professor Chen Zhen from Southeast University in China said in the latest research that they put solar heating panels and radiant cooling panels vertically stacked to develop a device that can heat and cool at the same time.

Chen Zhen told Xinhua News Agency that the solar panel made of germanium, a semiconductor material, can absorb photons in the solar wave band while allowing the mid-infrared band photons radiated by the radiant cooling plate at the bottom to pass unimpededly, between the radiant cooling plate and the surrounding environment. Use a vacuum device to achieve thermal isolation.

　　 Experiments show that the lower and upper parts of this equipment can be said to be "hot and cold". After the upper solar panel absorbs solar energy, the temperature can be 24 degrees Celsius higher than the surrounding environment; while the lower radiant refrigeration panel has an obvious cooling effect, and the temperature can be 29 degrees Celsius lower than the surrounding environment.

　　 Chen Zhen said that the solar panel in the experiment converts solar energy into heat, or it can be replaced with a solar panel to convert solar energy into electricity.

　　This kind of equipment, if applied on the roof of a building, is expected to provide heating or power generation energy on the one hand, and save air conditioning and cooling energy on the other hand. The research team next hopes to find cheaper materials to promote the large-scale application of this technology.