The Solar Digest for Solar Power, Solar Energy and Photovoltaic PV News - Test and Measurement
Pole-Mounted Thermal Inspection Of Solar Panels
- Published: Wednesday, 16 October 2013 07:36
This trend offers those involved in the roofing industry the potential to add value to their businesses by introducing the preventive maintenance of solar panels to their list of services.
Many will already be using thermal imaging to spot defects in roofs and to check the integrity of insulation and the technology is also perfect for solar panel inspection too. This non-contact method allows panels to be scanned whilst they are working, so the location and even the type fault can be seen on the thermal image.
The reasons why the roof top is an excellent choice of location for solar panels is obvious but it also poses a challenge too. How can these installations be inspected cost efficiently without incurring the expense of employing an access lift or platform?
Visiotherm, a building services’ company based in Belgium, has cracked the problem with an ingenious retractable pole system teamed with a FLIR T640 thermal imaging camera. When extended to maximum reach, the aluminium pole is approximately 12 metres in length allowing it to be used for solar panel inspection on most residential homes and low-rise industrial buildings.
On top of the retractable pole is a remote controlled pan and tilt mechanism that allows the FLIR T640 camera to be pointed to the target. It also allows the optimum operating angle to be achieved to eliminate any reflections that may skew results. The camera is controlled via wireless connection to a tablet PC that runs the FLIR Tools application software.
“This method of operation is just perfect for this application,” explains Visiotherm’s Patrick Robe. “We can change emissivity settings, adjust level and span, add temperature measurement points and perform other functions, all from ground level.” And he added, the FLIR T640 was the clear front runner for this work thanks to a variety of standard features on this model.
The FLIR T640 offers the highest thermal imaging resolution in its class for maximum inspection efficiency. It is an uncooled camera that produces crisp thermal images with a resolution of 640 x 480 pixels and can measure temperatures from -40◦C to 2000◦C with thermal sensitivity of less than 35mK.
This is particularly important for solar panel inspection as the camera sees heat distribution on the glass surface but only indirectly, the performance of underlying cells. The temperature differences that can be measured are therefore very small but thanks to sensitivity of the FLIR T640 they can easily been seen and even the nature of fault determined.
Wireless technology is standard on this model, a key feature for Visiotherm’s remote application. This also allows the camera to be used with a similarly enabled clamp meter whose data is automatically transferred to the camera and embedded in the thermal image.
Visiotherm’s model includes features such as thermal and visual image overlay and fusion but the latest generation of this popular camera goes further. It has FLIR’s unique multispectral dynamic imaging (MSX) as a standard feature that substantially enhances image detail and texture, another benefit for solar panel inspection.
As the weight of the entire Visiotherm thermal imaging system is 34kg, it is sufficiently portable to be set up on flat roofs as well as for thermal imaging from ground level. In this way, roofs greater than 12m in height can be inspected using a convenient flat roof as a vantage point.