Do you Need to Cool Down Solar Panels?
Solar Photovoltaic power generation is a fantastic technology with lots of benefits- the main highlight being that it cuts down the use of polluting fossil fuels as an energy source.
But, there’s one big hurdle of effective solar PV power generation: overheating of the solar panels, which decreases their efficiency.
So, with this in mind, is it necessary to cool solar panels to prevent overheating and the detrimental decrease in power output? What are the best strategies to cool down your solar panels?
Are cooling solar panels beneficial to you as a solar power consumer?
We’ve compiled this guide to answer these questions, so follow through, and you’ll know all that there is about cooling solar panels.
What is the Ideal Working Temperature for Solar Panels/Related Components?
According to solar panel manufacturers’ recommendations, the optimum working temperature of solar panels is 77◦F (25◦C).
At this temperature, solar panels are expected to absorb the maximum amount of sunlight and convert it to usable power (peak efficiency).
Past research agrees to what manufacturers recommend as the optimum temperature but extends it to be a range. The average range from many research findings is 59◦F -95◦F (15◦C-35◦C).
Other PV module components and their ideal temperature
Inverter: The inverter plays the crucial role of converting DC from solar panels to AC power. Most micro and central inverters for solar panels work best at ambient temperature, but they can tolerate temperatures of up to 45◦C (113◦F)
Solar batteries: If you have installed a solar panel array, you’ll need solar batteries to store the energy. Most solar-powered batteries will also work best at ambient temperature.
Inverters and solar batteries should be placed in cool places to prevent overheating.
Now that we mentioned that very high temperatures are not ideal for solar panels, what will happen if they overheat?
The Effect of Overheating on Solar Panels
The solar energy to usable power conversion done by solar panels will definitely go down if the surface temperature goes beyond the standard point. If you care about the output of your PV system, you should strategize on how to cool the modules.
With proper cooling, you should expect the efficiency of your solar panels to range at the upper limit of the standard efficiency (19-23%).
Causes solar panels degradation
High temperatures affect all electronics, and solar panels components are not spared. Heat buildup will also degrade the non-electronic components of solar panels such as framing, the glass sheet, and the top surface layer of the solar panels.
Eventually, the degradation will lead to a great loss of power.
Negative financial implication
Losing energy due to overheating means that you’re paying more for electricity. This defies the initial goal of having a PV solar system which is to save on electricity bills.
In addition to this, overheating damages your solar panels, meaning you’ll need to keep replacing them. This is another way you’ll unintentionally spend your money due to overheating.
Evidently, there are more than enough reasons why you should be cooling your solar panels frequently. But what ways should you use to cool your solar panels? Read below to find out.
How to Cool Solar Panels?
In this post, we’ll discuss 5 main strategies you can use to cool down your solar panels:
Strategy 1: Cooling solar panels with fans
Cooling solar panels with fans can reduce the temperature to around 59◦F (15◦C), which will lead to a significant increase in the system’s overall output.
According to an experiment done to compare the effectiveness of the DC water cooling system and DC brushless fans water cooling system, the latter increased the voltage, current, and output power by 3.47%, 29.55%, and 32.23%, respectively.
For fans to work in cooling solar panels, they must be integrated with temperature sensors that detect the temperature of the modules.
A microcontroller can be installed and integrated with the temperature sensors to switch solar panel fans on and off. This also ensures that the fans operate only when they’re needed (when the heat starts to build up).
Strategy 2: Cooling solar panels with water
This is the simplest and most common way of cooling solar panels. This method can work for all types of solar modules, and it’s as simple as spraying cool, pure water on the surface of the solar panels then waiting for them to cool off.
According to Akbarzadeh and Wadowski, who designed a hybrid PV/T s solar system, cooling solar panels with water can lead to around a 50% increase in output power.
One great benefit of cooling solar panels with water is that it also does the cleaning task. Even better, there are now improved water cooling designs that can collect the hot water from solar panels and use it for other heating purposes in the house.
Point to note: Whether the water spraying is done manually or automatically, it should be non-pressurized. Remember, solar panels are delicate, and you wouldn’t want to destroy them with high pressure.
Strategy 3: Ambient air cooling of solar panels
Ambient air cooling follows the heat and mass transfer principle that occurs between the solar panels’ surface and the ambient air. A system can be designed around the solar modules with an inlet and outlet for ambient air to transfer the heat from the solar panels.
Air cooling solar panels primarily depend on climatic conditions such as temperature, humidity, and airflow rate.
If, for example, the temperature of the ambient air that gets into the outlet is low, the temperature of the solar panels is reduced in the same proportion.
The dependence of air cooling on climatic conditions makes this method relatively less effective in cooling solar panels than other strategies.
Point to note: Although this strategy of cooling solar panels can work as a standalone method, it does best when integrated with another cooling method. You can, for example, combine it with water cooling to produce significant results.
Currently, there’re solar panels built with air cool technology, meaning that they operate at ambient temperature even when there’s peak sun energy.
So, before kicking off your PV solar system project, discuss with your solar installer and see if this is the type of solar panels you should be going for.
Strategy 4: Cooling solar panels with liquid nitrogen
Liquid Nitrogen is one of the most effective coolants in electronics. It has a boiling point of -320 ◦F (-196◦C).
Cooling solar panels with liquid nitrogen is an advanced technique that requires liquefaction units where the Nitrogen is first converted to liquid nitrogen.
The heat from the solar panels is circulated and captured by the liquid nitrogen, cooling the solar panels. The heat energy can later be converted to electricity, increasing the overall output of the system.
Clearly, cooling solar panels with liquid nitrogen is just an improved air cooling technique that leverages the convenient cooling power of liquid Nitrogen rather than ambient air.
Strategy 5: Cooling solar panels with wind turbines
Have you heard of hybrid wind and solar power production systems? It’s a technology that integrates solar panel arrays and wind turbines in the same area to enhance power production.
The rotating wind turbines (which should be placed strategically above the solar panels) circulate cool air around the modules, cooling them as fans do.
The good thing with wind-solar hybrid systems is that they’re complementary. The sun shines more when there’s less wind and vice versa. The implication is the production of a good amount of power all year through.
These are the main methods you can use to cool your solar panels.
But here’s a bonus:
Self-Cooling Solar Panels
Self-cooling solar panels is a new model of PV modules that can suck water to cool themselves.
These solar panels use condensed water as the coolant for the solar panels. The condensed water is water vapor in its liquid form.
These PV modules are made just like conventional ones but have a hydrogel sheet pressed on the backside.
The hydrogel has two roles:
- During the night, it collects water from the air (has a high affinity for water)
- At daytime, it pulls heat from the solar panels (it’s embedded in heat-absorbing carbon nanotubes)
The heat evaporates the water causing a cooling effect on the solar panels.
If you’ve been following the topic of solar panels cooling, I’m pretty sure you’ve come across the term ‘sweat’.
This term refers to the water vapor that evaporates from the solar panels’ surface, cooling the modules- just like the skin achieves the body cooling role.
Amount of hydrogel needed to cool solar panels
The hydrogel-forming sheet at the back of the solar panels can vary depending on the environmental humidity.
In hot areas with a humidity of around 35%, a 1m2 solar panel would require 1 kilogram of a hydrogel.
A pretty humid area with around 80% humidity would need 0.3 kilograms of hydrogel for a 1m2 solar panel.
Efficiency boost achieved by self-cooling solar panels
The ‘sweat’ technique can reduce the temperature of solar panels by 50◦F (10◦C). This temperature drop can push the production efficiency to the upper standard mark, which is around 19%-23%.
A superior design option
Researchers have not stopped at self-cooling solar panels. They now suggest that it could be coupled with solar panel self-cleaning.
It is suggested that the water that evaporates from the solar panels can still be recondensed and used to clean dust and grime that accumulates on solar panels, reducing efficiency.
If this is coupled with robotic cleaning systems, solar panels can be entirely maintenance-free. Even so, only time will tell if these scientific recommendations will revolutionize how we maintain solar panels.
Do Floating and Submerged Solar Panels Need Cooling?
Floating solar panels are always on the water surface, so the heat can never build up. The same case applies to submerged solar panels that always stay below the water surface.
Floating and submerged solar panels have water as their cooling system.
The cooling effect in these two models boosts efficiency, a reason why they’re gaining popularity nowadays. Keep in mind that these solar panels are very space-saving.
Cooling Solar Panels Before Cleaning
If it’s time to give your solar panels a nice wash, you should always cool them first. Sometimes the solar panels get so hot that it can be risky to touch them during the cleaning process.
Here, you’d want to use a combination of water spraying and ambient air cooling. Spray pure water on the panels, then wait for some minutes for them to cool down so that you can start washing them.
A better method is to wait for your solar panels to cool first by ambient air, then clean them. This is actually the recommended method of cleaning solar panels.
Do solar panels work best on hot or cool days?
To produce power, solar panels need sunlight. So, as long as the sun is up and shining, it doesn’t matter if the temperatures are cold or hot.
In view of our main discussion (solar panel cooling), it makes sense to conclude that solar panels work best on cold, sunny days.
Do solar panels work at night?
Solar panels don’t produce power at night. The same explanation applies- solar panels will only be functional if there’s sunlight.
So even if the temperatures are cool at night, it’ll have no impact on the production of your solar panels. You can read more about how to tap into the power of solar panels at night here.
Do solar panels work in winter?
As mentioned above, solar panels need sunlight, not heat, to produce electricity. In this regard, solar panels are not season-dependent and will work even in winter as long as there’s sunlight.
Must you use water to cool off solar panels?
There’re so many methods of cooling solar panels, so you’re not limited to water cooling. You can use fans, wind turbines, liquid nitrogen, or even hydrogel in the case of self-cooling solar panels.
The temperature of solar panels increases when they absorb solar radiation. Excessive heat build-up is an enemy of solar modules. It makes them work harder, degrade faster and produce less energy.
Cooling down your solar panels is extremely important, and it can boost the output of your solar PV system a great deal. You could end up saving more since your power consumption will lean more on the solar side, which you don’t have to pay for.
You can cool your solar panels with simple strategies such as water spraying or take it a little further and install fans for automated cooling.
Integrating several methods of cooling solar panels is even better, and it ensures that your solar panels are continuously operating at peak efficiency.