Paper Title
Solar Water Pumps For Agriculture

Abstract
Occupations in Thailand were mainly related to agriculture. Most Thais were agriculturists. Agriculture was heavily crucial to the development of the economy and the country. The incomes in Thailand densely came from agricultural products. Agriculture had a long-standing history in Thailand from the old days till now. Water was utilized for farming, planting, and livestock. Taking natural water from natural resource for agriculture at times required water pumps. In general, agriculturists used a petrol or diesel engine for swivel the shafts of a reciprocating pump. Alternatively, they deployed an electric pump which obtained electricity from a current transmission system, which was rather costly, and caused high product manufacturing costs. Nevertheless, at present, solar energy was being extensively promoted in Thailand, as it came from natural energy that was environmentally-friendly. The researcher came up with an idea of inventing a solar water pump for agriculture. A 250 watts, 24 VDC, speed 2,750 RPM (rounds per minute) to rotate the shaft of the piston stroke which was installed on a piston pump. The piston pump size was roughly 1 inch and it came with a flow rate of 2,800 liters per hour. The 2 connecting in parallel 150 watts, 12 volts solar cell panels for the piston pump and it was generated 300 watts of electric power. The solar cell panels were an electricity distribution source for the DC electric motor which came with a solar battery charger system. Such solar battery charging system with a 100Ah, 12 V battery for uninterruptible power supply when there was no sunlight to the operations of the water pump. When the solar cell panels of the designed and invented solar water pump were at 300 watts, 17 - 20 volts of electricity were produced which indicated that they could transmit sufficient current to the DC motor. Therefore, it was able to pump up water without being connected to a battery. A DC motor used 5.9 - 6.2 A, the speed was approximately 1,348 - 1,353 RPM which allowed the flow rate of 888 liters per hour. When the DC motor pump was used together with a 100 Ah, 12 Volt battery, the flow rate of pumping water lasted for 6.5 hours during the non- sunlight period. Keywords: Water pump, Piston pump, Solar energy, Solar cell.