Chapter 2 Solar System

Solar System

Chapter 02

Solar System

02.1 Solar Power System Solar power system is one of the renewable energy sources. Day by day developed countries are getting more concerned about the solar power system. Its initial cost is high but ultimately it is very cost effective. They are installing solar power system in almost every important position such as parking meter, street light, stadium etc. they are trying to be self dependent. Government Government is also helping them. Government not only inspiring them to use solar power system but also they are paying those people those are also giving the extra electricity to the grid. And they are given money two to three times more of the given electricity cost to the grid. As the initial cost is too high the people of developing and under developing countries are not getting too much concern. But some companies are coming to take the challenge of installing the solar power system and making people comfortable when there is no electricity. Recent electrical situation of Bangladesh is very critical. People of the urban areas of Bangladesh has to stay in blackout at least eight to twelve hours a day and it does not need to say long the people of the rural areas get electricity. Bangladesh is a small country with limited fuels, so to prevent the recent electricity problem the Government has to establish new power plant, it can be renewable or non-renewable, which is quiet troublesome. But if people use solar power system in their own building to meet their electricity needs, the electricity problem can be recover more or less. This system is called solar standalone system. This system does not need too much land and money but can fulfill the needs. Standalone system is not a commercial project and it is very effective for the electrical problem of Bangladesh.

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02.2 Types of Solar Electric System

People are using solar electric system as their own wish. Solar electric system makes people so much self-regulating that they are using this system as their own wish. Each system has its own merits and demerits. But each system has the merits of making people satisfied. The main types of solar electric systems [9] are-

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Grid linked or Grid Intertied Solar-Electric Systems

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Figure 5: Grid linked or Grid Intertied Solar-Electric Systems

Study of Solar Module & It’s Efficient Use in Bangladesh

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Grid-Intertied Solar-Electric Systems with Battery Backup

  y   p   o   C    t   o    N   o    D Figure 6: 'Hybrid' - Solar Electric and Generator Combination System

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Off-Grid Solar-Electric Systems

  y   p   o   C    t   o    N   o    D Figure 7: Small 'Stand-Alone' System

Figure8: Complete "Stand-Alone" Solar System

02.3 Working Principle of Solar Standalone System

The working principle of solar standalone system is very simple. It has two basic modes of operation. They are: Day Mode Night Mode

Study of Solar Module & It’s Efficient Use in Bangladesh

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i.

Day Mode

In the day, when there is enough sunlight, the sunlight falls on the PV panel. Panel produces electricity that goes to charge controller. The charge controller then supplies the load demand and rest of the charge used to recharge the battery.

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Figure 9: Working Principle of Solar Standalone System during Shiny Day ii. [[

Night Mode

At night or in cloudy day solar panel cannot generate enough energy to supply therefore storage batteries supply the load. As the batteries supply the loads, the voltage level of the battery gets down; this is being recovered at full sunlight.

02.4 Solar-powering a House

Every roof has the correct orientation or angle of inclination to take advantage of the sun's energy. Non-tracking PV systems in the Northern Hemisphere should point toward true south (this is the orientation). They should be inclined at an angle equal to the area's latitude to absorb the maximum amount of energy year-round. A different orientation and/or inclination could be used if you want to maximize energy production for the morning or afternoon, and/or the summer or winter. Of course, the modules should never be shaded by nearby trees or buildings, no matter the time of day or the time of year. In a PV module, even if just one of its 36 cells is shaded, power production will be reduced by more than half.

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If we have a house with an unshaded, south-facing roof, we need to decide what size system we need. This is complicated by the facts that our electricity production depends on the weather, which is never completely predictable, and that our electricity demand will also vary. These hurdles are fairly easy to clear. Meteorological data gives average monthly sunlight levels for different geographical areas. This takes into account rainfall and cloudy days, as well as altitude, humidity, and other more subtle factors. We should design for the worst month, so that we’ll have enough electricity all year. With that data, and knowing our average household demand (our utility bill conveniently lets we know how much energy we use every month), there are simple methods we can use to determine just how many PV modules we’ll need. We’ll also need to decide on a system voltage, which we can control by deciding how many modules to wire in series.

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02.5 Advantages and Disadvantages of Solar Electric System Advantages of Solar Energy

Solar cells are long lasting sources of energy which can be used almost anywhere. They are particularly useful in areas where there is no national grid and in areas where there is less population, such as in a remote site. Solar cells provide cost effective solutions to energy issues in places where there is no mains electricity. Solar cells are totally silent.

Rooftop power is a good way of supplying energy to a fast growing community. More cells can be added to homes and businesses as the community grows so that energy generation is in line with demand. Solar cells can also be installed in a distributed fashion, i.e. they don’t need largescale installations. Solar cells can easily be installed on roofs, which mean no new space is needed and each user can quietly generate their own energy. Solar power is a renewable resource. This means that we are not in danger of depleting its reserves. Though it may disappear behind clouds momentarily and is unavailable at night, it generally returns in full force. Solar power is non-polluting. Unlike oil, solar power usage does not emit any greenhouse gases, nor does the acquisition of it harm ecosystems through spills or dredging. This is probably one of the primary advantages of solar power. The energy and heat from the sun is free. Once solar panels or solar thermal collectors are set up, there are no electrical expenses necessary to power them. Study of Solar Module & It’s Efficient Use in Bangladesh

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Solar cells require very little maintenance, greatly because there are no moving parts that must be maintained. Solar cells can last a lifetime. Solar power is incredibly versatile. A variety of inventions may be powered by it, including cars, water heaters, fountains, buildings, and satellites. Solar cells offer more advantages over other renewable sources; as wind and water power relies on turbines which are noisy, expensive and more liable to breaking down. Solar power is simply a more harmonious energy resource. To obtain other energy sources, there is a requirement of harvesting fossil fuels, animal matter, or plant matter. Meanwhile, sunlight continually hits the earth in large amounts regardless of whether it is being utilized as an energy resource or not. Focusing solely on the application of solar power, instead of its application in addition to seeking out and obtaining the raw resource, omits an unnecessary step.

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Solar power is also an attractive investment due to the added value it gives a home. With the housing market slowing down considerably a solar power system definitely helps add to the desirability and resale value of a home. A home with a fixed electric bill from solar is less expensive to live in, and thus is very appealing to potential buyers. Disadvantages of Solar Energy

The initial cost is quite high.

Most types of solar cells require large areas of land to achieve average efficiency. Air pollution and weather can also have a large effect on the efficiency of the cells. The silicon used in cells is also very expensive.

Currently, solar energy costs about twice as much as traditional sources i.e. coal, oil etc. It offers the promise of free, clean, reliable energy, as well as a slew of other advantages on a larger social and economic scale. However, solar power is not perfect. Solar panels can only collect solar electricity about half the time. Given our relatively poor ability to store electricity at this time, this intermittency is a disadvantage. Grid-tied systems are a happy compromise and largely mitigate this problem for home solar power systems. Degradation of solar cell materials is another disadvantage. While current solar panels on the market will last 25-30 years and longer at reasonable efficiencies, they also cost a lot. The quest for high-efficiency low-cost solar panels is

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continually hindered by degradation. But once again, technology is improving so fast that today's major obstacle will likely be tomorrow's minor inconvenience.

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