Introduction
Why don't we try to find a new energy that is both sustainable and renewable?
Well, okay that part is over with but why aren't we using the knowledge that we've acquired to build our cities? Why are we still relying on energy sources that will reach its end in a short period of time?We live in a country that is highly subjected to constant solar rays throughout the year so why aren't we using it?
These questions come to our minds and evoke our thoughts and ideas, thus, wondering what could we do with this knowledge?
By using this newly appealed knowledge about solar rays and solar powers, we could purpose in transforming our university into an energy efficient campus. Therefore, finding a way to reach and demonstrate that endeavor without overlooking its practicality and feasibility.
The report revolves around one part, which is to find an alternative way to produce electricity for lighting. The plan is to station photovoltaic (or solar) panels over every street light and attach to it an adequate rechargeable battery so that in the daytime the batteries would charge and during the night the batteries will provide the street lights with sufficient charge to light up the university's streets without disturbing the public appearance.
Applying this idea, we discern that it has some disadvantages like cost, visual impact and consistency and reliability. However, we can't deal with the latter as it's a natural phenomenon but if we observe this project through a suitable time interval you find that the initial cost becomes inimitable when compared to the money we saved through this sustainable and renewable energy source.
Photovoltaic Solar Cell
Photovoltaic Meaning
The word 'photovoltaic' (commonly abbreviated to PV) comes from a Greek word 'photos' meaning 'light' and 'volt' ' the System International unit for electromotive force, named after its discoverer, Alessandro Volta. PV solar modules generate electricity from the sun's light. They have no moving parts, require little maintenance, and they produce electricity from a free fuel without polluting the environment. 'Solar energy is referred to as renewable and/or sustainable energy because it will be available as long as the sun continues to shine.' (Foster, 2010, p. 5).
A brief history of PV power
The PV effect was first discovered in 1839 by French physicist Edmond Becquerel. He found that when you shine a light upon certain metals, a stream of particles (later found to be electrons) is emitted from that metal. However, it was only in 1883 that Charles Fritts built the first solar cell, by coating selenium with a thin layer of gold to form the junctions. It was less than 1 per cent efficient.
Experimentation showed that the number of electrons emitted by the metal depended on the intensity of the light beam applied on the metal; the more intense the beam, the higher the number of electrons emitted, but no electrons are emitted until the light reaches a threshold frequency, no matter how intense the light is. It was not until 1905 that scientists fathomed why emitted electrons move with greater speed if the light has higher frequency, when Albert Einstein described the quantum nature of light and its behavior as a wave as well as a stream of particles (later called photons).
The first use of this novel invention was to power instruments on board the second US spacecraft, Vanguard I, in 1958, and thenceforth it was the space race that financed their rapid development.
Timeline of Solar Cells
From 1839 to 1953 physicists dedicated themselves into investigating the truth behind solar cells by experimentation and deep observation. Such that in 1883 Charles Fritts developed a solar cell using selenium on a thin layer of gold to form a device giving less than 1% efficiency and in 1905 Albert Einstein published a paper explaining the photoelectric effect on a quantum basis. However, the first modern solar cells were invented in 1954 by Bell Labs. These cells have about 6% efficiency. After that the New York Times forecasted that solar cells will eventually lead to a source of "limitless energy of the sun.'
In 1958, Hoffman Electronics created 9% efficient solar cells. Vanguard I, the first solar powered satellite, was launched with a 0.1W, 100 cm'' solar panel.
In 1977, the world production of photovoltaic cells exceeded 500 kW and in 1978 the first solar-powered calculators were created.
In 1983, worldwide photovoltaic production exceeded 21.3 megawatts, and sales exceeded $250 million.Global production of photovoltaic cells grew by 10% in 2012 in comparison to 2011 (Figure 1)
('Deferred compensation,' n.d.)
In accordance to this revolution in the photovoltaic industry (Figure 2), Kahdpekar (2012) said 'Solar energy which is known to be a clean and competent technology is over time becoming eminently possible to capture, in that the costs have been steadily falling. In the meanwhile, the technology is also being considerably refined in all the areas of operation. With the payback situations improving, solar is no longer considered a boutique option for those that can afford the indulgences in renewable sources of energy. While passive solar has been in use since millennia, the progress in technologies from simple flat plate to future orbital technologies, current solar energy has come a long way since the path breaking impact it made in mid-19th century. Social and environmental costs need to be seen against the long-term irreversible costs of the damage done by fossil fuels.' (p. 57).
Photovoltaic Applications
1) Introduction
Due to its modular and small scale nature, PV is ideal for decentralized applications. At the start of the twenty-first century, over one-quarter of the world's population did not have access to electricity, and this is where PV can have its greatest impact. With millions of small residential PV systems installed on homes around the world, most commonly as small stand-alone PV systems, but also increasingly as larger on-grid systems in some industrialized regions (Japan, California, and Germany). 'Solar energy is unique in that it can easily provide electricity and purified water for these people today with minimal infrastructure requirements by using local energy resources that promote local economic development.'(Foster, & Cota, (2010), p.2).
2) Applicability
PV for Schools: Thousands of rural schools in the developing world do not have access to electrical grid power. It is important to bridge this gap so that rural student populations living outside electricity grid services can also have the same opportunities as other students. An enhanced quality of education forms a foundation for increased productivity, leading to higher standards of living. Solar power technologies can be used to bring services, such as distance education and computer internet access.
PV for protected areas: Renewable energy technologies have been widely applied to support protected areas throughout Latin America, especially in Mexico and Ecuador. Key environmental agencies such as the Nature Conservancy, World Wildlife, and Conservation International have embraced PV technologies because PV systems provide power without the noise or pollution associated with conventional fossil-fueled generators, while reducing the risk of fuel spills in these sensitive biosphere reserves.
PV ice-making:It has not been widely deployed yet, but there have been some attempts. The world's first automatic commercial PV ice-making system was installed in March 1999 to serve the inland fishing community of Chorreras in Chihauhau, Mexico (Figure 3). The system was designed and installed by SunWire.
Stand-Alone Photovoltaic
Stand-Alone PV applications
Over the past quarter century, the developing world has adopted stand-alone PV technologies in earnest for social and economic development. PV is a viable alternative to traditional large-scale rural grid systems. With the advent of PV as a dependable modern technology alternative and more private participation and choices made available to the general public, PV systems have become attractive throughout the less developed parts of the world. The challenge is to develop financing strategies that are affordable to potential clients. One of the biggest appliances of this technology is stand-alone solar street lighting.
Stand Alone System meaning
It is an outdoor system unit used to generate electricity for a specific load. Stand Alone Systems operates from Dusk to Dawn.
Standalone systems have photovoltaic panels mounted on the roof. Each roof has its own photovoltaic panel and is independent of the other. This procedure has advantages and some disadvantages.
Advantages
1) Stand Alone Systems are independent of the utility grid. Hence, the operation costs are minimized.
2) Stand Alone Systems require much less maintenance compared to conventional street lights.
3) Since external wires are eliminated, risk of accidents is minimized.
4) This is a non-polluting source of electricity
5) Separate parts of solar system can be easily carried to the remote areas
Disadvantages
1) Initial investment is higher compared to conventional street lights.
2) Risk of theft is higher as equipment costs are comparatively higher.
3) Snow or dust, combined with moisture can accumulate on horizontal PV-panels and reduce or even stop energy production. This could be dealt with an automatic solar panel cleaner that uses some of the electricity produced to clean the solar panel.
Apparatus
Solar Photovoltaic (SPV) Module:
SPV module is fixed firmly on top of the roof with suitable tilt and inclination so as to receive maximum sunlight throughout the day. The SPV module thus produces suitable voltage and current, which is used to charge the battery inside the battery box. This energy stored in the battery is used to provide electricity for different loads in a commercial building.
Battery:
The energy generated by the SPV module is stored in the battery then used to provide electricity during night time. Low maintenance cylindrical lead acid type battery is normally used.
Charge Controller Unit:
The Charge Controller Unit (CCU) is the heart of the system, which controls the charging and discharging of the battery. CCU will increase the battery life by not allowing the battery to deep discharge and overcharge. During deep discharge conditions, the CCU will disconnect the light and a red LED glows on the luminary indicating that the battery is low and needs charging. The green LED on the luminary indicates that the battery is resuming charge. During overcharge conditions the CCU will disconnect the solar module and prevents overcharging of the battery.
Loads:
The loads that are going to be used in the office.
Interconnecting Cables:
The SPV module, luminary and battery are interconnected through the cables.
Summary
The sun is credited with being a free, abundant and inexhaustible source of solar energy which has the advantage of having a low environmental footprint. Conventional power generating and transmission technology is becoming increasingly expensive to manage in terms of high investment in new reserves while the demand for power is always rising. While the solar energy capital and generation cost is currently high, three to four times more expensive than conventional energy, the costs in this sector have been declining on an average of four percent annually, considered one of the fastest declines of any energy source. This decline in costs is driven by continuous advances in photovoltaic technology and manufacturing economies of scale. While global renewable energy capacities grew at the rate of 15-20 percent annually for many technologies, grid connected solar PV technology recorded 60 percent annual average growth for the 5-year period beginning 2002. Therefor in order to preserve energy, money and the environment the first step into turning the University of Sharjah into a clean-energy foundation is to cut the streetlights off the grid and apply stand-alone solar street light technology followed by other stand-alone technologies realizing that the geographical area is consistently subjected to solar rays throughout the year.Following Ghassemi& Cota's saying (2010) 'The future will be a mix of energy technologies with renewable sources such as solar, wind and biomass playing an increasingly important role in the new global energy economy.' (p.2).