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Solar Power |
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Solar Power |
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The principle of converting sunshine into electricity (photovoltaic effect) was discovered in 1839. However it was not until 1941 that the first commercial Photovoltaics Cells (Solar Panels) were manufactured. Prior to this time small solar cells were quite small and were used mainly to power small electronic devices such as exposure meters for photography and some specialised technical instruments requiring only very low power. In the early 1940 the first panels were made that had sufficient power to charge batteries and drive equipment. These early panels were very expensive and it was not until the 1970's that mass production help bring the cost down to a commercially viable level. The new millennium has seen the emergence of solar power as a serious contender to address the problems of greenhouse gasses caused by huge coal and oil powered power stations. In Europe there are now whole factories operating on Solar Power. In the domestic market there are three main applications for photovoltaics. |
| Stand alone power systems (SAPS) | ||
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These systems collect solar energy using photovoltaic panels and convert this energy to electricity which is stored in deep cycle batteries. The output of the PV's is regulated to operate at 12,24 or in large systems 48 volts dc. The stored energy is then increased to 240volts ac. through an inverter and provides 'mains quality' power to all lighting and electrical loads through a standard electrical switchboard.
The diagram at right is a schematic drawing of a typical installation. |
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Solar array Battery bank
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| Grid connect systems | ||
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The solar panels in these systems are configured to produce very high dc volts. (Up to 600 volts). This is then fed directly into a 'grid interactive' inverter which synchronises the phase of a 240 ac volt output to the phase being delivered by the mains. There are no batteries in these systems. These installations are usually carried out for customers who enjoy the convenience of mains power but who wish to contribute 'green power' to the grid and in doing so reduce the amount of greenhouse gasses generated by coal and oil fired power stations. As the amount of solar power collected is not quite as critical to supply household power the angle of the array is also less crucial and panels are quite often installed in 'low profile' mode for aesthetic reasons. |
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| Direct drive systems | ||
| For electrical loads that only need to operate during daylight hours, it is possible to match the load with a suitably sized solar array feeding power through a 'solar controller' or 'maximum power point tracker'. This type of installation is ideal for remote area pumping and in a suburban situation can reduce the run-time and cost of swimming pool filters significantly. The solar powered pump starts automatically as soon as the sun rises each morning and continues throughout the day until sunset. There are no batteries required for these systems. |
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