Introducing Solar Water Pumps
Solar water pumps have applications in remote or rural irrigation water pumping as well as in urban borewell water supply and pumped storage systems.
Effective water pumping is important factor in India’s socio-economic development. India’s agricultural sector accounts for around 14 % of its GDP but more than 60 % of the population’s livelihood depends on agriculture and upwards of 50 % of its agricultural land depends on monsoons. Below average monsoon raises concerns for everyone in India, especially farmers for whom irrigation consists of 30% of the costs of production.
Lack of access to electricity and intermittent power supply are mostly countered by using diesel powered water pumps which greatly increase cost of production and thus lowers income from farming which has a long term impact on India’s GDP.
Why should we use a solar water pump?
Solar PhotoVoltaic (PV) energy is gaining prominence due to its plentiful availability in India and water pumping is an important application of solar PV power. The solar pumping system serves to provide water in remote applications where electrical grid power is either unreliable or unavailable. Case for Solar PV based water pumping solution is simple. If it’s raining, you won’t need the pump that much; if it’s sunny the pump will work just great. It’s a “win-win” plan for all. The solar pumping system provides water to remote locations by converting high voltage, direct current from a solar array into alternating current to run a standard three-phase asynchronous motor. A solar electric array generates electricity from the sun’s light with no moving or wearing parts. A solar pump is designed to utilize the direct current from the array efficiently, even as the energy production varies throughout the day.
What happens when the sun doesn’t shine?
Depending on the application, a solar pumping system may use a water storage tank. Remember the goal of the solar water pumping system must be to store water not electricity. Since the sun is only available during certain hours of a day and only in good weather conditions, the water is generally pumped into a storage pool or tank for further usage, and water sources are those natural or special such as river, lake, well or waterway, etc.
How do solar water pump systems compare diesel generator based pumps?
Where electricity grid is unavailable or intermittent solar systems are often the most economical of all the options. Considering costs, such as installation, ongoing fuel requirements, maintenance and waste, solar water pumping is much less expensive than diesel generators. Solar water pumping systems have many advantages over diesel generator based water pumps. The lifetime costs of solar powered systems are often far less than diesel generator based water pumps due to lower maintenance costs.
How does the right solar water pump controller work?
The solar pump controller runs at variable speed to match the changing power available from the solar array. Variable speed operation means there is no inrush or surge of energy during the pump/motor start-up, helping to eliminate wear on the motor and pumping system. A leading cause of pump motor failure is the stress applied to the motor during a full voltage start-up. The solar variable speed operation ramps up the speed smoothly, which eliminates starting stress. This feature enhances long-term motor reliability. The solar AC pump controller also monitors system performance and can detect a variety of abnormal conditions continuously. In many cases, the controller will compensate as needed to maintain continuous system operation; however, if there is high risk of equipment damage, the controller will protect the system and display the fault code. If possible, the controller will try to restart itself when the fault condition passes. High quality solar pump controllers are designed for full power operation from the optimized solar array in common ambient temperatures. Under extreme conditions, the controller will reduce output power in an attempt to avoid shutdown. Full pump output is restored when the controller temperature cools to a safe level. The solar AC pump controller is a variable speed motor drive designed to run any IEC three-phase asynchronous AC motor. The solar pump controller is designed to provide these features with the plug and play ease of installation.
How can I reduce the costs of solar water pumping system?
A PV system may incorporate storage batteries that can be charged when incoming solar energy exceeds the pumping power requirement. The batteries can then be used to power the pump when the pumping requirement exceeds the solar power input. However, the use of batteries should be discouraged unless absolutely necessary since the added expense and complexity usually outweighs any advantages. A more effective and less expensive means of utilizing excess incoming solar energy would be to incorporate a water storage tank into the system. A storage tank can help meet the operation’s water needs when the demand exceeds the pump output or during non-peak solar hours when only minimal solar energy is generated. The cost can also be reduced by harnessing more power per unit installed capacity of the solar panel. One method of realising this is by Maximum Power Point Tracking (MPPT) wherein a power electronic converter is used to match pump with the PV panel. Widely employed approach for MPPT is to monitor the PV panel power and keep on adjusting the duty cycle of converter so that tapped power is always maximum.
Why isn’t everyone using solar water pumps?
Briefly, they will, very soon. Solar water pumping systems have had mild success, so far in India. Typical solar water pumping in India uses makeshift borrowed technology involving brute force system over sizing and unreliable electrical components running submersible BLDC pumps. This tends to be expensive, inefficient and cumbersome. However a more elegant and integrated power electronics based solution that runs the most common AC pump types used in India is a simpler and more effective remedy to this unique application. It optimizes system size, drastically reduces component failure rates and increases system efficiency and life, all while making it easier to install and maintain. Solar power based water pumps core design features lends to the rugged weather and use conditions that such solutions would be subjected to. Best of all it is cost efficient which is a big decision making factor in this extremely price sensitive market segment. So get ready for the future where solar water pumps are common sight in farms and urban localities all over India.