PV lighting at an office usings LEDs

Abstract: Although lighting systems powered by photovaltaics (PV) cells have existed for many years, they are not widely used, due to their high initial cost and low conversion efficiency. One of the challenges facing PV powered lighting systems has been how to use DC power generated by PV modules to energize light sources that are designed to function with AC power. Usually the efficacy of DC light sources is very poor compared to AC light sources. LED lighting bulb is a new technology which is fast growing with several diverging views about its efficiency and whether they can replace the conversional lamps. Following the introduction of white and high-power LEDs, many companies are developing products that aim to replace the traditional illumination sources. With the initial high cost of PV power the goal of all solar energy engineers is to improve efficiency and decrease the cost so it can be affordable.The first part of this research deals with replacing the conventional fluorescent lighting system in an office room with 12V DC powered LED lamps. The essence is to have the same illumination and comfort as what exist with the conventional lamps and compare the two systems. The second part deals with determining which portion of the electric load of SERC could be run on DC current.The conventional fluorescent lamps expend 168W power to provde the illumination in the office room with the six (6) bulbs that are used.However, it will take (43) 12-LED lamps, (17) 45-LED lamps, (40) 99-LED lamps and (15) 48-LED lamps; which sum up to 115 different LED lamps with different power consumptions to provide the same illumination. All put together, will expend 339W power whiles the lamps will cost 12187 SEK.In the second part, the electrical load of the office building (SERC) was determined and hence the possible equipment and and electrical load that could be run on DC.A total of 17.16MWh out of the 72.142MWh determined electrical load of SERC could be used on DC.