Design of Solar Photovoltaic System to Power Air Conditioning Unit for A Light City Train (Case Study on Addis Ababa Light Rail)
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Date
2020-10
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Addis Ababa University
Abstract
Energy is the basic utility required to drive trains. Trains use either fossil fuel or electricity to energize the system. The Addis Ababa city light rail has two routes namely: the North-south Line (MENILIK II Square to KALITI Route) and the East-west Line. The train gets electricity from the grid. Electrical energy coming from the grid enters the control unit from where to be supplied to different units. One of the energy-intensive units is the air-conditioning system.
This research work focused on designing a rooftop solar photovoltaic system to provide the energy required for the air conditioning units of the 17.1 kilometers from Ayat to Torhailoch Route. The data collected from the Ethiopian Methodology Agency, NASA, and PVGIS showed the sun can be provided at minimum solar insolation of 4.8 kWh/m²/day to the route line. The air conditioning system of the train is a DLD25 type air conditioning unit. The cooling capacity is 6 kW and power of 2.25 kW for each AC, the air supply volume is 1300m3/h, and the total electrical power is 9 kW for 4 air conditioner.
The train travels at an average speed of 70 km/h without significantly changing its direction from East to West and vice versa. In a coach, 36 photovoltaic modules (having a 66.35 m2 aperture area) can be installed in an effective rooftop area of 71.6 m2. The battery size is 150Ah, 12V controller size of 80 A, 220V, and 30 KW of inverter size. The PVSYST and MATLAB software simulation results projected within different months electrical energy varying between 11.48 kW and 14.45 kW can be generated.
The train in general requires 260 kW of electricity. Of this 9 kW or 3.5 % amount of energy is consumed by the air conditioner. Hence, by supplementing the locomotive with solar PV modules 1034775 Birr can be substitute per annum. As compared to other researches, this thesis work is to simplify the mounting of the solar PV modules by considered the solar insolation variation within the route to know the performance of the system. Hence it is recommended to Addis Ababa Light Rail Train to apply this solar-powered air conditioning system.
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Keywords
Solar energy, photovoltaic (PV), light train, PVSYST, MATLAB, air conditioning