Solar Water Pumps: What Are They And How Do They Work
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Solar Water Pumps: What Are They And How Do They Work

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In the modern-day, mechanical pumps serve a myriad of purposes. They can be useful in pond filtering, aquarium filtering, pumping oil, and other use cases. Traditionally, we have seen fossil fuel-powered pumps being the most popular resort for most people.

In recent times, the tryst to achieve electricity using renewable energy has led to the development of several alternative sources for pumping water. One such mechanical pump type is the solar water pump. It was very costly when it started, but the prices have come down considerably in the last two decades. It has led to broader acceptance for them and people finding alternate uses.

Even though other pumping mechanisms find usage in several fields, solar water pumps are especially gaining traction in irrigation. Because of their ability to effortlessly operate in scenarios where other mechanisms fail, they are fast becoming the go-to for many poor and remote areas.

In this article, we discuss how a solar water pump operates, the advantages and disadvantages of using it, and its various types.

What is a solar water pump?

We all know that solar power is one of the cleanest energy sources on the earth and is also the easiest way to produce electricity. It is also helpful for farmers in the remote part of this world who suffer because of the lack of proper infrastructure around their farms.

Solar irrigation is simple – when the sun is up, you can utilize it to power your irrigation system by harnessing its energy into a solar water pump. A solar water pump is a clean alternative to traditional electric-driven pump sets.

The major components of a solar water pump include a PV (PhotoVoltaic) array, an electronic motor, and a pump. Depending on their motor’s abilities, these can either draw AC (Alternating Current) or DC (Direct Current). The new-age BLDC (Brushless DC) motors are more powerful and energy-efficient.

How does it work?

The photovoltaic modules of the solar water pump capture sunlight and convert it into electricity. There are no moving parts here, only silicon cells which utilize the energy from the panels. Also present is a pumping mechanism, which includes diaphragm, vane, and piston pumps, to draw water from the source.

In most situations, you are likely to find a solar pump established at ground level or found submerged in the water. These are most efficient when you draw water from a maximum of 20 feet away from them.

Additionally, a solar water pump also needs a pump controller. It is an automatic that manages the operating time of the machine and turns it off in inefficient conditions. Some high-end models also inculcate a float switch, which turns off the grid when full and prevents it from suffering a voltage shock.

You are likely to find a solar tracker fitted in some of these machines. They work best during excellent sunlight conditions and help in improving energy suction by up to 50 %.  The tracker is a moving part which tilts the solar panels across the sky but will require repair periodically.

The last part you will find in most solar water pump sets is a storage unit. Depending on the location and ancillary reasons, you may require up to 10 days of storage. These come with deep cell batteries to ensure that the pump works consistently even in overcast conditions.

In a solar water pump, the photovoltaic cells provide electricity to power an electric motor. The motor powers a surface or a submersed pump. Depending on the type, it follows its requisite mechanism to pump water through the cavity into the storage tank. It creates a gravity feed and powers the ending process, saving the need for any energy storage or fossil fuels.

How does it differ from other water pumping systems?

Solar water pumps differ significantly from other pumping mechanisms, owing mainly to the inputs it requires. While these are more environmentally friendly than diesel or gas-based ones, solar water pumps cannot operate throughout the day like them. Compared to windmill-based pumps, solar pumps are more comfortable to set up and do not require experts to manage them.

Hauling water pumps are labour intensive, and that works against them. At the same time, ram-based ones require constant moving water for them to operate, which is not the case with the solar-based mechanism. Gravity-based are better than solar water pumps in most cases, but we can set them up in limited areas restricting their use cases.

Use cases of solar water pumps

Solar water pumps are often the only method of automated irrigation in remote areas. The mechanism is also useful in churning out clean drinking water in the regions which do not have access to it otherwise. Depending on the type you use, you can also use it to filter small ponds and pools. Depending on where you use it and your usage pattern, you can find the right size.

Types of solar water pumps

If we talk of standalone solar pumping systems, you will find rotating and positive displacement pumps. Based on usage, here are the types of solar water pumps you are most likely to come across –

Submersible solar water pumps

Submersible solar water pumps, as the name suggests, can be submerged in the water. These work best in wells and boreholes. They only use the push mechanism to remove the fluid and produce energy during the process.

Surface solar water pumps

Surface solar water pumps are not submerged in the water. These are, instead, kept above the water level. Because of this, they find usage in lakes, pools, rivers, ponds, and similar scenarios. They use both suck and push mechanisms to transfer water from one storage to another.

These can either be portable or solar pool pumps. The former helps irrigate fields and other use cases which require you to move the energy source continuously for maximum efficiency. The solar pool pumps are helpful in areas which lack grid connectivity. These are used in filtering pools regularly with the help of the energy produced by the sun.

Advantages

No fuel cost

One of the primary reasons why the world is shifting to renewable energy sources is to protect fossil fuels as they take far longer to replenish naturally. With solar water pumps, you only utilize the sun’s energy, and there is no requirement of any other fossil fuel energy for it to operate. It allows users to operate it at almost nil cost.

Environment-friendly

Unlike fossil water pumps, which are known to by-produce pollutants harmful for the environment, solar water pumps produce clean energy. Another reason they are considered environment-friendly is that they don’t use any non-renewable energy to power themselves. With fossil reserves plummeting at record levels, solar water pumps are fast becoming the more feasible and sensible option.

Minimum manual interference

Most solar water pumps are entirely automatic. These also help you in minimizing labour and time needed to irrigate your fields. Unlike a fossil fuel pump where you need to replenish the fuel tank every few days, solar water pumps use solar power, which is renewable automatically. Also, most of these are non-movable, ensuring longer sustenance and minimum repair costs throughout their lifetime.

Disadvantages

Cannot be used in overcast conditions

It is not necessarily a disadvantage, but something that you must know before buying a solar water pump. It means if you are looking to operate it after dusk or early morning, you may find it cumbersome. But careful planning and using a sizable battery can improve its utility and maximize its efficiency. Adding a battery in the mix helps you to compensate for such unwanted situations.

High initial investment

You will need to buy the solar water pump setup at once. Most of its parts are costly and require massive investment initially. But these are cheaper if you are looking to establish them for long-term. With the cost of solar panels falling and their improving efficiency, it is implicit that they will become a better investment in the coming years.

Solar water pumps are the future

If we date back to a few years, most people didn’t opt for solar water pumps owing to their enormous costs and paltry efficiency. In the last few years, these have improved on both counts which have propelled their market share.

An International Renewable Energy Agency (IRENA) survey states that the prices of solar water pumps will go down by 59 % by 2025 compared to their prices in 2015. In 1997, the approximate cost of solar energy per watt was USD 76. In comparison, it came down to USD 0.3 in 2015 and continues to fall further.

One gripe people may have is the initial investment involved, but given the longevity and minimum repair costs involved, it should not be a concern too. Given the benefits all along, it is easier to visualize solar water pumps as one of the key players in the market within the next few years.

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