Using Submerged Solar Panels for Swimming Pools

Swimming in warm water is all refreshing and amazing until it comes to paying electricity bills for the energy spent to heat the water. It can really get expensive, especially if your swimming pool is always in operation.

But did you know that with submerged solar panels, you can maintain your pool at the right temperature without having to dig deep into your pockets?

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Imagine utilizing the available space in a swimming pool to produce electricity, then using the power to heat the pool water.

Exploiting solar energy to heat your swimming pool is a cost-effective strategy that will reduce the overall maintenance cost of this magnificent home add-on.

And it doesn’t stop there. You can leverage the excess power produced by the array for household power uses such as lighting.

In this post, we’ll have a closer look at submerged solar panels for swimming pools to understand how they work. Read on to find out if this is a worthy investment for your home.

Can Solar Panels Work when Fully Submerged in Water?

To answer this, let’s look at some past research findings.

A group of researchers from the Birla Institute of Technology and Science, Pilani and DRDO, Kanpur, tested how amorphous silicon solar cells would perform underwater and found out that there could be potential applications for submerged modules.

The researchers used amorphous silicon solar cells coated with polydimethylsiloxane (PDMS), which is the most commonly used waterproofing silicon-based polymer in optoelectronics.

The material allows the required light penetration to occur while waterproofing the modules.

Generally, all solar panels are waterproofed by sealant glue. Otherwise, they could not withstand rain. However, for submerged applications, it’s critical to coat the modules with an excellent hydrophobic material such as PDMS.

So yes, photovoltaics (PV) modules submerged in water will still perform their role as expected. Contrary to what many people think, solar panels are highly water-friendly and they’ll always perform excellently when there’s a medium to cool them.

How do Submerged Pool Solar Panels Work?

Swimming pools in homes are mostly installed in areas with strong solar radiation, meaning enough sunlight can be collected and converted to electricity.

Submerged PV modules are usually installed on the edge or floor of the swimming pool to collect the sun rays and convert them to electricity. If a battery system is installed, you can store the energy produced by the fully submerged modules and use it elsewhere, say in your house, for lighting.

Pure water is an excellent visible light absorber- it acts like a light filter that blocks the photon from the red-infrared (700nm-1mm) region and allows the visible spectrum (350 nm-550 nm) to seep in.

This light filtering property of water favors the working of submerged solar panels in a pool.

Submerging solar panels in swimming pools reduces thermal drifts and overheating. This greatly boosts the panel’s production efficiency.

The solar array produces power that can be used to heat the pool’s water. The excess power can be used in the house for lighting or powering devices.

Evidently, installing submerged solar panels in your swimming pool is an investment that carries many benefits for your home.

The Expected Production Capacity of Submerged Solar Panels in Pools

A standard swimming pool is 60 m2 and 1.2 meter-deep. Assuming that the entire 60m2 is covered with solar panels, you should expect the whole system to produce around 10,000KWh per year. This is quite an amount of power for an average power-consuming household.

As mentioned above, this power can be used for both pool heating and in the house for lighting or for powering devices such as a solar refrigerator.

What Module Types can be used as Submerged Solar Panels for Swimming Pools?

For this, it depends on where the solar panels are placed on the pool.

There’re two main installation spots for submerged solar panels:

• Edge of the pool- Here, mono-crystalline and poly-crystalline solar panels are the best choices.
• Pool’s floor- For pool floor installations, amorphous silicon solar panels perform best. Polycrystalline solar panels may still be used if the swimming pool is not too deep.

Here are the reasons for the above recommendations:

Usually, the crystalline solar panels lose around 20% efficiency when they hit the 1m depth mark. On the other hand, amorphous silicon solar panels offer a standard efficiency of up to 1.5m depth.

Without considering shading that may be present in the swimming pool, the crystalline solar panels hit 10-20% efficiency effortlessly.

Submerged Solar Panels for Pool Heating

The most important application of submerged solar panels is swimming pool heating. For this to work, the pool must have an existing heating system. In many swimming pools, heat tanks are used to conserve thermal energy.

The thermal photovoltaic panels are submerged in the pool and installed near the hot water storage tank. A water layer circulation is superimposed to the PV panels, and an insulating layer runs at the back to reduce thermal loss.

This system can heat water to around (40-50) ◦C. The water is kept in the hot water tank, and with a heat exchanger, it can be circulated to heat up the swimming pool. Additionally, the water can be extracted from the tank and utilized for domestic purposes.

A submerged solar pool heater can reduce energy use by 75%. Note that this reduction extends to the money you spend on electricity.

Heat loss through convection, evaporation, radiation, and conduction from the walls of the solar panels is inevitable. However, you’ll still save a lot in the long run.

Tip to consider: To reduce power loss by evaporation at night, cover the pool with a thin film cover.

Like in electrical efficiency, submerged solar panels have better thermal efficiency since they’re not affected by thermal drifts.

Floating Solar Panels vs. Submerged Solar Panels vs. On-Ground Solar Panels

Factor	Submerged solar panels	Floating solar panels	On-ground solar panels
Electrical efficiency	Great efficiency when the right modules are installed	High efficiency due to low heat buildup	Standard efficiency due to overheating
Design	Highly specialized design to tap into the maximum potential of the PV technology under submerged conditions.	The design must work with all the other components used to keep the entire system floating.	Simple design since the working conditions are favorable.
Power loss	Reduced power loss due to reduced thermal drift in addition to light filtering offered by water above the panels.	Cooling of the modules reduces power loss significantly.	Power loss may occur due to heat build-up.
Best modular types	Amorphous silicon solar panels work great even when they’re 1.5m, below the water surface.	Monocrystalline and polycrystalline solar panels.	All types of modules work just fine.
Suitable application(s)	Pool water heating, lighting, and civic home power use.	The power is usually fed to the grid and distributed for business and home use.	Perfect for home direct power use.

The shading Effect and its Impact on Submerged Swimming Pool Solar Panels

Shading is obstruction of the normal flow of solar energy into solar panels in pools.

For submerged solar panels to perform maximally in a swimming pool, they must be placed in a strategic spot.

The most important consideration here is ensuring they’re not set in shaded areas. Shading leads to local overheating that can ruin the entire module.

Essentially, there’re two types of shading patterns:

• Length side-shading
• Breath-side shading

Breadth-side shading causes more power loss than length-side shading, but all in all, you should work with your solar installer to identify the best spot to install the solar panels. Open space swimming pools are great for submerged PV systems.

Additional tips to reduce the impact of shading

Have a microinverter for each solar panel

Connecting each solar panel to a microinverter can help your system handle the shading problem better. Generally speaking, if one panel is shaded, it’ll not affect the output of the other, so the overall output won’t change significantly.

Install thin-film solar panels

Sure, thin-film technology has its own drawbacks, but it’s great for counteracting the impact of shading.

Invest in solar panels with bypass diodes

Solar panels with bypass diodes have shown great results in rectifying the effect of shading. Make a sound investment to make the most out of the submerged solar panels swimming- pool project.

Advantages of Submerged Pool Solar Panels

Superbly efficient

There’s no heat build-up in submerged solar panels for swimming pools, so solar to power conversion is not compromised in any way.

Effortless cleaning

Submerging solar panels in swimming pools puts them in the ideal environment for cleaning. They can be cleaned when water changes in the pool are done or any other time since they’re easily accessible. What’s more, the modules will hardly accumulate dirt since they’re always in the water.

Add to electric power generation in a home

Submerged solar panels leverage the free energy from the sun to generate more electricity for your home. Tapping into solar energy can help cut your electricity bills significantly.

Better space exploitation in your home

A swimming pool takes up free space in a home. One way you can make it more productive is by installing submerged solar panels to produce power.

Maintain the pool water at a desirable temperature

The power produced by the submerged solar panels can be used to heat the pool water. This is highly cost-effective since it eliminates the need for installing expensive solar heating systems.

Essentially, installing submerged solar panels in your swimming pool makes it self-sustaining.

Disadvantages of Submerged Pool Solar Panels

Specialized design

To leverage the maximum potential of submerged solar panels, special designing technologies must be used to tune the modules for the water conditions. A big section of the design goes to waterproofing the solar panels.

Possible loss of energy when there’s a lot of radiation absorption

If the swimming pool water is highly contaminated, only little sun radiation will reach the solar panels. So, for this investment, you must be ready to keep your pool water clean at all times.

Wrong module choice may lead to low efficiency

As mentioned above, not all solar panels will work well under submerged conditions. If, for example, monocrystalline solar panels are installed on a pool floor that’s more than 1m deep, the system will operate way below standard efficiency.

Possible visual impact in swimming pools

If submerged solar panels are excessively used or improperly installed, they can change the visual appeal of a swimming pool.

The initial structure of the swimming pool may also be altered to accommodate the installation of the modules, affecting the appeal even more.

Related Questions

Wrapping Up

Liquid solar arrays are now taking over conventional energy production. Submerged solar panels can now be used to effectively heat swimming pools, with only a fraction of the cost you’d need if you were to install conventional heating systems.

Heating swimming pool water with solar instead of relying on grid power is cost-effective, highly convenient, and environment-friendly.

The most interesting thing about pool solar panels is that they produce electricity that you can still use to boost what your roof or ground arrays are already producing.

So, if you’ve been wondering if installing photovoltaic submerged solar panels for your swimming pool is a worthy investment, you now know that it’s one of the brilliant improvement projects you can do in your home.