Therethermography on solar panelsserves to identify the so-calledhot spot, the "hot spots" which are the most blatant symptom of a malfunction of the photovoltaic panel.
- What is thermography?
Application of thermography in photovoltaics
Therethermographyit is an analysis that sees the use ofthermal imaging camerasboth in the field of construction and in the maintenance of photovoltaic systems; particular thermographic analyzes are also widespread in the medical field.
In the contextphotovoltaic, thanks to the thermal cameras we go to investigate the presence of a possibleoverheating of photovoltaic panels.
The thermal imaging camera is a device capable of capturing "thermal images", in simpler words we can describe thethermal imaging cameralike a camera equipped with special sensors capable of detecting the surface temperature of the bodies and making it readable in an easy to understand color map.
- When to rely on photovoltaic thermography?
Photovoltaic system that produces little energy
If you have assumed the occurrence of aoverheating of photovoltaic panelswith the genesis of the so-calledhot spot, it is necessary to intervene with a thermographic analysis. Usually, the presence of the "hot spots" might make you think you are dealing withdefective photovoltaic modules when in reality the problem could also be related to a few solar cells! In some cases, the failure of a few cells can cause a drop in production that can be as high as 90%, and now we will see why.
We usually rely on thermographic analysis when thephotovoltaic system it has a lower yield than that guaranteed by the manufacturer. Thanks tothermography on solar panels, it will be possible to locate the modules not working and replace it. A thermographic analysis could be very useful especially if the system is still under warranty in order to return the cells that are no longer functional and obtain their free replacement.
- The concept ofphotovoltaic hot spot
What are the hot spots and how they can decrease the yield of the plant
We have told you that it is sufficient to scan the photovoltaic system with a thermal imager to identify the presence ofhot spot but we have not yet explained in detail what the so-called arepoints hot. To explain well what hot spots are, we need to introduce the concept ofNOCT photovoltaic.
NOCT is the acronym forNominal Operating Cell Temperture, Nominal working temperature of the cells. This parameter, supplied by the manufacturer, is typically equal to 40-50 ° C but can reach 60 ° C forphotovoltaic systemsin double glazing.
THEsolar panelsthey work best at lower temperatures, around 25 ° C. Higher temperatures significantly reduce the efficiency of the system due tooverheating of the photovoltaic modules. The hot spots, orhot spot, represent thosedefective cellsthat yesoverheatand which cause serious drops in production.
- Why can a few faulty cells cause a significant decrease in plant production?
Why does the faulty cell behave like areverse biased diode, so as to trigger a sort of chain reaction that compromises the production of electricity on all the other cells connected in series.
When installing aphotovoltaic system, the technicians prepare by-pass diodes on most of the photovoltaic panels, so if one fails, the others continue to produce energy and the damage is limited to one module; unfortunately in practice this ideal model does not always win, so a 3-cell failure can compromise the entire system.
- Photovoltaic system that does not produce. What to do?
- Why does my photovoltaic system produce less energy than it should?
In the photo above, simultaneous inspection of several photovoltaic panels with identification of a photovoltaic hot spot with Fluke thermal imaging camera.