Over the last few decades, researchers around the world have been working tirelessly to come up with more innovative and efficient ways to harness solar power. Companies like Dell and Johnson & Johnson are already sourcing 100% of their energy needs from renewable sources. Even retail chains like Kohl’s and Whole Foods have taken the responsible step towards green energy, to reduce costs and attract more customers.
Getting the Most Out of Solar Energy
If you aren’t already utilizing cheap and clean solar energy, you should start gearing up right away. Here’s a crash course in five practical ways you could extract maximum benefits from this unlimited natural resource:
1. Photovoltaic Systems (PV systems) – These are panels made from materials that, when exposed to sunlight, use heat and light to shake electrons loose and create an electric current in a process called the photovoltaic effect.
- A typical commercial PV cell has an efficiency of about 15%, which yields consistent renewable energy for years.
- A typical installation includes arrays of PV cells on the south-facing side that are either fixed at an angle or used with a tracking device that swivels them for maximum efficiency.
- The second generation thin-film solar cells (TFSC) are just a few millimeters thick and can be installed as laminates on virtually any surface. They range from shingles and roof-tiles to entire building facades that can generate electricity.
2. Solar Water Heating – Solar collectors are usually rectangular chambers with multiple small tubes called flat-plate collectors, which circulate water or another fluid.
- Pipes are attached to a black-painted plate or heat-absorber and the top surface is transparent, allowing sunlight in and trapping its heat, which is then transferred to the liquid.
- Active systems use a pump to circulate fluids between the collector and a heating system. As it circulates, the heat absorbed by the collector is transferred to the fluid. This hot fluid is stored in a tank and used to heat water.
- Passive systems are simpler systems that use gravity, typically heating the water directly, without the need for any pumps. As water flows through, it heats up and is stored in a tank, ready for use.
3. Passive Solar Energy – Passive solar heating and lighting can be achieved both directly and indirectly, through one of two popular methods.
- Direct Gain utilizes materials that absorb heat from the sun, in places that receive direct sunlight and radiate it through the night. Sunspaces work similarly, using sunlight to heat an area and circulating air through it to the rest of the building.
- Trombe walls are thick walls on the south side, which are painted black and made from heat-absorbent materials. A transparent panel that’s a few inches away is used to trap heat better, so the entire wall works like a giant radiator at night.
4. Solar Thermal Electricity – Solar energy can be concentrated to heat water and run turbines to produce clean-electricity. There are three main systems for concentrating sunlight, which are used to meet different requirements.
- Parabolic-trough systems use mirrors curved to a u-shape and lined together to form a trough. They focus sunlight to superheat a pipe that circulates oil, which is then used to generate steam.
- Dish/engine involves mirrors installed on a satellite dish-like structure, which concentrate the heat on a receiver. A fluid absorbs the heat and either expands and drives a piston, or is used to boil water.
- A power tower uses a large field with mirrors that swivel to reflect a huge area of sunlight onto a tower in the middle. The extreme heat is used to heat molten salt which is piped into a boiler.
5. Solar Heating and Cooling – For offices and larger buildings, solar energy can be more efficiently harnessed, as compared to houses and smaller premises. On a larger scale, even parabolic-trough collectors can be used for space heating and solar water heating in place of traditional methods.
- Evacuated-tube collectors heat fluids in tubes which have evacuated glass double-walls. The vacuum between the walls works as an insulator, just like a thermos, to dramatically increase efficiency.
- With some science, solar energy can be used to power cooling systems. Developments like desiccant-cooling allow super-efficient evaporative cooling systems to be used, even in high humidity.
Solar energy on a commercial scale was (until recently) expensive, inefficient and often unreliable. With modern technology and manufacturing processes, it’s become one of the easiest ways to harness clean low-cost and environmentally-friendly energy. Plug into the massive power of the sun and watch your workplace reap the benefits for years to come!
About the Author: Julia Young is a green movement activist and believes in advancing sustainability. She was taught to value and conserve natural resources by her parents and has grown up with a mindset which reflects the same. Currently, she is working as an online marketing manager for Vista Solar (www.vista-solar.com), a bay area based commercial solar power installation firm. She is also an avid blogger on topics related to environmental sustainability and solar energy. She can be reached at firstname.lastname@example.org.