Monthly Archives: May 2015

How Do Solar Cells Work?

Solar Cell Converting Sunlight_To_Electricity_How_It_Works

We are pretty well aware of the process that converts electrical current into light from which we can pierce darkness and find our way around a house, street or entire neighborhood. But what has taken a lot of time to master has been converting light (specifically, sunlight) back into electric current to power homes, calculators, satellites and many other items through the use of solar energy.

One of the tools used to make this solar-powered electricity has been the solar cell, also knowns as a photovoltaic, or PV cell. It takes many PV or solar cells to make a single solar panel that goes on top of a home, but it takes only a few to make the solar panel that runs a basic calculator.

The solar cell is where the magic happens in turning sunlight into usable energy. How do solar cells work to make this happen? Let’s take a deeper look into the construction and operation of a solar cell.

Sunlight as a Hammer

The first thing that has to be understood is the power of solar energy and what sunlight can do to contribute to electric power. In physics, there is a photoelectric effect, in that any material can eject electrons when sunlight shines on it. Sunlight is like a hammer on a rock; the photons in sunlight hit the atoms and molecules of a material (for solar cells, we use silicon) and breaks the bonds that hold electrons in the “orbit” of the atom, releasing the electrons.

There free electrons are what makes the electric current. The key is corralling all these free-wheeling electrons and getting them to move in an orderly fashion so as to create an electric current. This is where the solar cell does its work.

Solar Cells: The Silicon Corral

A solar cell is made of a semi-conducting material, such as silicon. When sunlight hits the silicon in the solar cell, some of the sun’s energy is absorbed by the silicon like a sponge, and that energy breaks loose some electrons from the silicon atoms and they become “free agents,” so to speak.

The silicon in the solar cell is actually two types thanks to “doping” with other elements – one is n-type, which has spare electrons, and p-type, which has gaps where electrons should be. These two types of silicon are right next to each other and they provide a sort of “channel” that gathers these “free agent” electrons, corrals them, and – thanks to metal contacts on either end of the broader solar panel – send them in an orderly fashion down the channel and toward the contacts to produce electric current.

Solar Cells: Why So Expensive?

This is an interesting question. It is well known that silicon is very abundant on the earth, and is the cheapest semi-conducting material on the planet. So if it’s so cheap, how come solar power is so expensive?

It’s a complex question, but from a scientific point of view the reason is this – silicon possesses a high electric resistance, which means there are a lot of electrons that are not able to achieve an electric current. This means the solar panels have to be much larger in order to generate the current needed to power the electricity of a home, water heater or parking garage. Plus, silicon absorbs a lot of energy, which means there is wasted sunlight in a sense that is unable to be converted into electricity.

One of the ways that solar power and solar cells could eventually be cheaper is to make them smaller. There is a semi-conducting material called gallium arsenide, which allows free electrons to flow up to five times faster on its surface than silicon, and it has properties that allow it to absorb less sunlight energy and convert more of it into electricity. It works well for satellites and some military applications, but it is very expensive to produce and very difficult to make in a large commercial scale for solar panels.

However, with further development and research, scientists are looking into a thin-layer gallium arsenide overlay on silicon solar cells (as well as silicon wafers for microchips) to at least bring some of the characteristics of gallium arsenide to a silicon solar cell, potentially degrading its resistance and absorption and increasing the efficiency of the cell to make it more powerful and thus, cheaper in the long run.

5 Ways More Luxury Hotels Are Going Green

luxury eco friendly hotel

One of the most common causes amongst the world today, with the exception of a few outliers, is conservation and going green. We know our planet has taken a beating from an environmental standpoint due to emissions from greenhouse gases. Each person can play a small role in determining the future outcome of our planet. However, a larger role can be played by big businesses.

Luckily, there are a number of industries getting on board with going green and the hospitality industry is one them. Even the ultra-luxury hotels are beginning to realize the pivotal role they play in reducing the harm their waste gives off to the environment. Among standard recycling and water conservation, luxury hotels are also making the change to green in some very big ways.

Solar Panels

One of the main ways that luxury hotels are beginning to go green is through solar paneling. These solar panels provide the energy needed to operate their hotel without the use of fossil fuels.

A big proponent of this movement is the large hotel chain, Starwood Hotels. This global hotel establishment has been making real steps towards implementing solar energy in all of its Starwood Brand hotels. They began with one of their most luxurious resorts, located on the Virgin Islands, by installing a 1.3-megawatt solar array. Furthermore, the hotel chain has goals to decrease overall energy consumption by 30 percent and water consumption by 20 percent. It has set itself a 2020 deadline for these goals.

With so much real estate, hotels are primed candidates for solar paneling. As much as every person loves a good rooftop pool, it is nice to see some hotels make rooftop solar panels a priority.

Wind Turbines

Another way luxury hotels are going green is through the use of wind energy. Wind energy is another clean and renewable source of energy that is ideal for hotels. The Hilton in Ft. Lauderdale is a role model for other luxury hotels due to its wind turbine technology. This sustainable energy source is provided from the six wind turbines located on top of the hotel. The large wind turbines don’t detract from the overall luxuriousness or customer experience at the hotel.

Geothermal Energy

Hotel chains have also began taking advantage of geothermal energy. This sounds a lot more complex than wind and solar energy but in reality, it is an exceptional way for large industrial businesses to implement sustainable energy sources. Geothermal energy comes from large water sources, either a geothermal lake or an aquifer. The Peppermill Resort Spa Casino in Reno, Nevada opted for a geothermal aquifer that is buried 4,400 feet under its casino. The water is kept at a modest 174 degrees Fahrenheit and is pumped to the resort. This water is the resort’s heating source. Overall this system saves the resort over $2 million per year in energy costs.

Drought Resistant Greenscaping

Not all luxury resorts are created equal and not all luxury resorts have large iconic brands to fund them. However, that doesn’t mean that the smaller luxury resorts can’t play their part in an effort to go green.

One way that luxury hotels are going green is through drought resistant greenscaping. One of the biggest wastes in a hotel is the water. A combination of staff and guests pour through enormous amounts of water each day whether it is through tap water waste, showers, laundry, and toilet flushing. However, another culprit behind some massive water waste is the greenscape around hotels.

It takes a lot of watering to keep much of the plantlife looking green and lively. Automated sprinkler systems or teams of landscapers come through to greenery almost daily at luxury hotels. However, hotels have been opting for drought resistant landscaping. Among the drought resistant plants growing in popularity are succulents. These plants need very little water to keep them colorful and lively. These incredible plants can be placed almost anywhere, including adding them to the interior design plans of a hotel.

Water Harvesting

Finally, luxury hotels have also been going green through simple and almost free measures. The old saying goes, “When it rains, it pours”. Well, the new saying should be “When it rains, catch it”. Water harvesting has become increasingly popular amongst not only in the residential sector but in the commercial sector as well.

Each rainfall provides a natural resource that hotels would otherwise have to pay for. Hotels can use this rain water for a number of things including watering those indoor plants to keep them green and lively. It may not seem like a glamorous or luxurious thing to do, but hotels that do this can save money and use it elsewhere. Like on chocolate pillow mints that somehow taste better than regular chocolate mints.