Solar Photo Voltaic Water Pumping System

Abstract

Water pumping is an important application of solar photo voltaic (PV) power. However growth in the number of solar pumps is not promising mainly due to higher cost per litre of water pumped and complex technology. These issues can be addressed by harnessing more power per unit installed capacity of solar panel and making the system simple. Present research work has dealt with the aspect of harnessing more power from PV panel using maximum power point tracking (MPPT) for a standalone water pumping system. Literature review indicates the need for MPPT method which is simple, accurate as well as non-interruptive in nature. This thesis has proposed a novel method for accomplishing MPPT wherein only load voltage is to be used as control parameter for MPPT converter (MPPTlv). This method is simpler than the present more commonly employed method of monitoring panel power (MPPTpp) which requires measurement of two parameters (panel voltage & current) and then multiplying them to obtain power. The proposal is substantiated by theoretical explanation and results from simulation & experimental testing. In addition to its simplicity, the new proposal is also found to give higher power output and enhance water yield. An algorithm is developed to show simulation implementation of the proposal made. Another outcome of the present research work is the development of a new strategy “Individual Floor Storage Method (IFSM)” for solar pumping in multi-floored buildings where over head (OH) tanks act as storage elements. Present practice is “Top Floor Storage Method (TFSM)" wherein one single large OH tank is placed on topmost floor. IFSM proposes to employ small tanks at each floor height supplying water to corresponding floor. Water is pumped to the required optimum heights only, avoiding wastage of energy. For a particular power capacity of solar panel, the amount of water lifted will be more. Effective total cost per litre of water lifted is appreciably reduced. In other words, for a particular amount of water to be lifted per day, the PV panel size needs to be less. The two new proposals made in this research work, giving increased water yield from the solar pump for a particular capacity of solar panel, are expected increase the acceptability of solar water pumps and thus contribute to their growth.