Solar panels consist of complex structures called solar modules. Each module contains numerous intricately engineered solar cells that are interconnected. This interconnection allows for the flow of current.
However, what happens when this flow is disrupted? When one or more cells in a string are unable to generate sufficient current, solar hotspots are created. These hotspots elevate the risk of fires.
What are solar hotspots?
To understand hotspots in solar panels, consider a scenario where one of the cells in your solar panel becomes shaded or soiled. Shaded cells act as resistance and obstruct the forward flow of current. Since the solar cells are connected in series, the weak cells reduce the overall energy output of the solar panel.
To address these situations, solar companies incorporate bypass diodes into their panels. When a weak cell hampers the current flow, the diodes are activated, providing an alternative path. Check out the diagram below.
Source: Ornate Solar
However, diodes are only a stopgap. If a diode stops working, a shaded cell will consume energy rather than produce it. This causes the shaded cell to steal energy from the other cells, which results in overheating.
The overheated areas are referred to as hotspots.
Hotspots can have significant consequences. A 2018 study found that hotstops can reduce a solar system’s energy production by more than 15%. And according to Ornate Solar, hotspots cause 22% of solar panel failures.
If hotspots are not addressed, the overheating can cause damage to the panels. This damage can include broken glass, melted underlying sheets, and even fire.
Can You See a Hotspot?
In most cases, hotspots cannot be seen with the naked eye. However, hotspots will sometimes appear as brown marks.
Since hotspots are hard to see, it’s important to continuously monitor the performance of your solar system to determine the power generated by each panel. If energy production drops unexpectedly, you need to take a closer look.
Detecting hotspot issues efficiently requires specialized measurement techniques. Thermography is the most effective method.
Thermographic images can capture the temperature distribution of solar panels, allowing for the identification of hotspots with a high level of accuracy. Check out an example of a thermographic image below.
Source: pv magazine
7 Steps to Stopping Solar Hotspots
It’s hard to correct hotspots after they occur. However, there are many things that you can do to reduce the risk of hotspot formation.
1) Ensure adequate airflow maintenance
Hotspots are created by heat accumulation. If your solar panel system lacks sufficient airflow, such as a protective covering, the risk of hotspot formation increases.
A well-designed solar panel system will prioritize adequate ventilation and airflow to prevent panels from overheating.
One effective way to cool your panels is to use a power optimizer that automatically reduces electricity output in response to high temperatures. This technique maintains optimal production levels without the need for manual intervention.
2) Implement bypass diodes
As explained earlier, bypass diodes redirect electrical current around shaded or damaged solar cells. This minimizes the occurrence of hotspots.
Each individual solar panel typically has bypass diodes installed, and larger panels may feature multiple bypass diodes. These diodes automatically activate when they detect reduced power output due to shading. The diodes divert the current through an alternative path, bypassing the affected cells.
In addition to preventing hotspots, bypass diodes can also help solar panels last longer, according to Solartechadvisor.
3) Get a solar tracking system
Solar tracking systems actively adjust the position of solar panels to face the sun instead of leaving them stationary.
These systems contribute to reducing hotspot effects by continually exposing the panel to direct sunlight throughout the day. However, solar tracking systems are pricey. A typical tracking system in the US costs between $500 and $1,000 per panel.
4) Use backsheets
Manufacturers also have the option to use glass types that possess specific properties. These properties cause the glass to reduce heat instead of simply absorb heat.
Employing a backsheet material with high thermal conductivity is recommended to facilitate heat dissipation from the panel.
5) Make sure that your panel installation is obstruction-free
Another important hotspot prevention tip is to install your panels without any obstructions. Male sure that the panels are not closely spaced or shaded by other objects.
Trees and buildings are the most prevalent obstructions to be mindful of. Additionally, installing the panels away from any potential shadows will be advantageous.
6) Ensure correct angles
Installing the panels at the correct angle aids in minimizing hotspot effects. Online resources are available to assist in determining the optimal angle based on your location.
7) Read the manufacturer’s instructions thoroughly
Lastly, carefully review your manufacturer’s recommendations. The manufacturer possesses valuable insights regarding how to optimize your system’s performance and minimize issues.