Solar Water Pumping System Fundamentals:
Harnessing natural energy to pump water has been around for over a thousand years. Before the invention of the solar water-powered pump, Dutch engineers had been using windmills to pump water for over 1000 years. However, when it came to pumping water, using the wind proved reliable. It was so effective that the Dutch could save more than half of their country from the sea simply by using wind energy to pump water out to sea.
In the 1970s, solar water pumping was invented. At the time, the system was simple: solar panels and a DC/AC water pump. It has since been refined and perfected. As a result, solar water-powered pumps can now be found in various industries, including agriculture, industry, and residential settings.
Solar water-powered pumps are becoming increasingly popular in agriculture. One reason is that most agricultural areas are frequently expensive and remote from the power grid. Bringing grid power to agricultural fields is frequently prohibitively expensive. Furthermore, using fossil fuels is often costly due to rising global prices.
The fact that most irrigation must be done during the dry season is a significant advantage of using solar water-powered pumping agricultural fields. In addition, this is frequently the season with the highest solar intensity and clear skies. As a result, there are optimal conditions for harvesting solar energy when it is most needed.
How Does It Work?
Solar water pump systems are a relatively recent concept. However, the mechanics are very similar to all other water pumping systems. It uses positive displacement and kinetic energy principles to move water from one location to another. Any mechanical system requires energy to function. First, solar-powered water pumps convert the sun’s rays (photons) into electricity, which powers the water pump. Next, it employs solar panels to collect photons (units of light) from the sun, resulting in direct current (DC) that powers the motor to pump water away from its source. Finally, it uses the sun’s energy to mechanical power bits, transporting water from an authority, such as a river, storage tank, or underground well, to a predetermined destination. This location could be an agricultural field or a storage tank for domestic use. Solar water pumping is as effective as, if not more effective than, other water pumping systems such as fossil fuel pumps. A solar pump system is made up of three main parts. These are solar panels, an inverter for the solar pump, and a water pump. At its most basic, a solar water-powered pump is an electric pump that is powered by electricity generated by solar panels.
The first component is solar panels, which gather the sun’s energy and convert it into electric power. These panels must be optimally positioned to receive as much sunlight as possible. Occasionally, a tracker may be installed to ensure that the boards are facing an optimal direction to receive the sun’s rays. This energy is then sent to the solar VFD (variable-frequency drive converter).
When the sun’s rays are weak, the solar pump controller controls the solar pump and keeps it from stalling. Some advanced controllers include features such as a float switch terminal where the pump can be turned off when the water tank is full. In addition, they may feature overvoltage protection.
Another critical component of any solar water pumping system is the water pump. Pumps are available in a variety of configurations. Submersible, circulator, and booster are the three most common types of pumps.
Submersible pumps are frequently used in solar water pump systems that extract water from deep wells or boreholes. On the other hand, a circulator pump is commonly used to circulate water to keep it warm and ensure a continuous water supply. Finally, the booster pump provides the necessary pressure to move water from a storage tank to the entire facility.
Here’s a video that explains how it works.
Operation of a solar pumping system
WHERE CAN A SOLAR WATER PUMP SYSTEM WORK?
Solar water pumps can be used in any part of the world where there is enough sunlight. They are ideal for off-grid, rural areas where bringing the grid would be prohibitively expensive. As a result, they are the perfect solution for most of South America, South Asia, Southeast Asia, and Africa. These areas all have high solar insolation but low grid connectivity. On the other hand, a solar water pump system can be installed in almost every habitable region.
One of the most basic applications for a solar water pump is providing home water. In addition, they can be used to provide water in remote medical clinics, villages, private homes, and other locations. The solar pump can pump water to an elevated water storage tank.
A solar-powered water pump can provide water for livestock in addition to providing water for a home. It can be particularly beneficial for cattle ranches in southern Africa, the Americas, and Australia. Rather than driving cattle long distances to get to the water, it can be continuously pumped to conveniently located watering points. Solar water pumps are already widely used in these areas, where they are used to pump water through up to 5 kilometers of pipelines.
Solar water pumps can benefit small farms, vineyards, and gardens. For example, pumping water directly into a gravity tank and distributing it via gravity flow is the most cost-effective configuration for a small garden.
There is no limit to the size of solar pumps that can be manufactured. However, it is frequently the case that using them in small installations is the most cost-effective, where the use of fossil fuel systems would be inconvenient. Some of the most miniature solar water pumps can run on 150W of PV and lift water from as far below ground as 200 feet. This is at a rate of more than 5 liters per minute. Using this system, a 10-hour sunny day can produce 3400 liters of water. This amount is sufficient to irrigate a small orchard, a small herd of cattle, or several small family units. These are primarily DC solar pump systems if you only need small water plants. AC solar pump systems are more popular because they have larger water plants to meet various water demands, and their performance is more stable.
Here’s a demo video on installing a solar water pump system.
WHAT ARE SOLAR PUMP SYSTEMS’ BENEFITS?
One advantage of using a solar pump system is that it allows you to use low-yield water sources. In addition, slow solar pumping systems can potentially reduce the cost of installing long pipelines. Because the length of the pipes does not affect the amount of energy required to pump water, water can be pushed over long distances at a low cost.
Another advantage of using a small solar pumping system is that it does not require specialized knowledge. Anyone with basic literacy skills can read the simple setup instructions for a small solar pump. It is beneficial in rural areas where locating technical experts and equipment would be difficult.
A solar water pump system is typically low-maintenance once installed. This is an excellent benefit for remote areas where getting spare parts and technicians would be difficult. Once installed, a solar water pumping system can run for years without needing to be repaired. In contrast, fossil-fuel water pumping systems frequently require extensive maintenance throughout their operational life. In most cases, the only care needed for a solar water pump system is removing dust and debris from the photovoltaic panels.
What Does It Cost?
According to some market research sources, a solar water pump kit for irrigation costs between $2000 and $5000 for a solar array and pump and all connections.
The kit includes a pump between $1200 and $2500, with solar panels costing no more than $2 per watt.
The total cost of a pump kit is heavily influenced by water demand in terms of flow rate, daily volume, and buyer shipping.
Costs are also affected by the source of water. For example, surface water systems, such as those that draw from a pond or river, will be less expensive due to lower energy demand than deep-well water pumps.
There are seasonal discounts that are frequently quite substantial, with up to 25% off the retail price. Look for sales and use price trackers to receive instant alerts.
Conclusion: The Advantages and Drawbacks of Solar Water Pumps
Solar water pumps are more efficient solutions for many off-grid watering applications.
The technology is suitable for a wide range of water requirements but is best suited to low-flow systems.
Solar pumps are also ideal for areas where other power sources are unavailable or prohibitively expensive. Crop irrigation, refilling livestock water basins, and regulating water levels in ponds and lakes are the most relevant applications.
Solar-powered pumps can supply gravity-fed systems and distribute stored water. Pumps can be used for both surface and groundwater sources.
Many retailers sell self-contained solar well pump kits that include solar panels and all other components needed for a simple installation.
Power and unit lifespan are the most significant trade-offs.
Solar pumps sacrifice maximum lift power in exchange for efficiency. As a result, even at peak solar intensity, there are limits to the rate at which solar energy can be converted to electricity.
Solar water pumps are not economically competitive for deep water or high flow rate requirements. In addition, even if the system is operational, pushing it to its upper limit increases wear and tear on pump components. This increases the need to service or replace the system.
You can wire backup systems for a gas-powered generator and the utility grid into the breaker box as insurance against insufficient solar power.
The solar array and pump will require regular maintenance and periodic system component upgrades regardless of the power load.
Although such systems’ lifespan is limited, numerous practical and cost-effective applications justify the investment.
Improvements to existing designs will further advance this technology as interest in solar pumping systems grows.