Dr S S Verma
When comfort and laziness styles of living beat tolerant and austerity life styles then human fails to cope up with the existing/prevailing environmental/seasonal changes all around and thus, technology remains the only answer for the wrong boos of changing lifestyle. Summer and winters seasons always concern people more than other seasons and they get serious to cope up with these severities of climate using technology. In winter people can make use of more clothes but summer can be overcome by using electrical driven cooling appliances like
Cool Building
Fans, Coolers,ACs and Fridges etc. But with the summers getting hotter (due to global warming) and growing electricity demand, people are forced to think about some future innovations which can be useful to beat the summer heat in more economical and effective way. A warming world needs cooling technologies that don’t require power. Cosmic fridge is such a new technique to design buildings with high-tech mirror which can beams heat away from buildings into space. Such a technology can prove to be a boon for people living in very hot zones of the country like Punjab, Haryana, Rajasthan, parts of Bihar & UP, Madhya Pradesh, Odissa, West Bengal, Jharkhand and Gujarat. Across the developing world, photonic radiative cooling makes off-grid cooling a possibility in rural regions, in addition to meeting skyrocketing demand for air conditioning in urban areas.
Summer heating
Much of the human population on Earth lives in sun-drenched regions huddled around the equator. Electrical demand to drive air conditioners is skyrocketing in these places, presenting an economic and an environmental challenge. These areas tend to be poor and the power necessary to drive cooling usually means fossil-fuel power plants that compound the greenhouse gas problem. In addition to these regions, we can foresee applications for radiative cooling in off-the-grid areas of the developing world where air conditioning is not even possible at this time. There are large numbers of people who could benefit from such systems. Forty-fifty percent of the total consumption of energy takes place in buildings, so reducing this consumption is becoming increasingly important. Integrating renewables into the energy supply for buildings is a further step towards moving towards this aim. People usually see space as a source of heat from the sun, but away from the sun outer space is really a cold, cold place. A new type of structure reflects the vast majority of sunlight, while at the same time it sends heat into that coldness, which cools human made structures even in the day time. Such a panel could vastly improve the daylight cooling of buildings, cars and other structures by radiating sunlight back into the chilly vacuum of space. First, the reflector has to reflect as much of the sunlight as possible. The second challenge is that the structure must efficiently radiate heat back into space. Thus, the structure must emit thermal radiation very efficiently within a specific wavelength range in which the atmosphere is nearly transparent. Outside this range, Earth’s atmosphere simply reflects the light back down. The new structure accomplishes both goals. It is an effective a broadband mirror for solar light — it reflects most of the sunlight. It also emits thermal radiation very efficiently within the crucial wavelength range needed to escape Earth’s atmosphere.
Technology
Engineers have invented a material designed to help cool buildings. The material reflects incoming sunlight on sunny days and sends heat from inside the structure directly into space as infrared radiation. A new ultrathin multilayered material can cool buildings without air conditioning by radiating warmth from inside the buildings into space while also reflecting sunlight to reduce incoming heat. The heart of the invention is an ultrathin, multilayered material that deals with light, both invisible and visible, in a new way. Invisible light in the form of infrared radiation is one of the ways that all objects and living things throw off heat. When we stand in front of a closed oven without touching it, the heat we feel is infrared light. This invisible, heat-bearing light is what the Stanford invention shunts away from buildings and sends into space. The new material, in addition to dealing with infrared light, is also a stunningly efficient mirror that reflects virtually all of the incoming sunlight that strikes it. The results will cooler buildings that require less air conditioning. The researchers say they designed the material to be cost-effective for large-scale deployment on building rooftops. Though it’s still a young technology, they believe it could one day reduce demand for electricity. In practice the researchers think the coating might be sprayed on a more solid material to make it suitable for withstanding the elements.
The research team has succeeded by turning to nano structured photonic materials. The material is made of quartz and silicon carbide, both very weak absorbers of sunlight.
These materials can be engineered to enhance or suppress light reflection in certain wavelengths. The thermal emitter and solar reflector are combined into one device, making it both higher performance and much more robust and practically relevant and this design makes viable both industrial-scale and off-grid applications. But transmitting heat into space is not enough on its own. This multilayered coating also acts as a highly efficient mirror, preventing 97 percent of sunlight from striking the building and heating it up. Together, the radiation and reflection make the photonic radiative cooler nearly 9 degrees Fahrenheit cooler than the surrounding air during the day. The multilayered material is just 1.8 microns thick, thinner than the thinnest aluminum foil. It is made of seven layers of silicon dioxide and hafnium oxide on top of a thin layer of silver. These layers are not a uniform thickness, but are instead engineered to create a new material. Its internal structure is tuned to radiate infrared rays at a frequency that lets them pass into space without warming the air near the building. Radiative cooling has another profound advantage over all other cooling strategy such as air-conditioner. It is a passive technology. It requires no energy. It has no moving parts. It is easy to maintain. Put it on the roof or the sides of buildings and it starts working immediately.
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