|The FLIR entry level thermal cameras|
The camera basically measure IR (heat) radiation from the objects you are taking the picture of. The camera software uses the IR radiation levels and your estimate of the emissivity of the object to estimate the surface temperatures of the object. The camera converts the temperatures into a colored image where each temperature maps to a color shade.
The camera produces images like this:
|Thermal image of Kristy the dog.|
My main reason for buying the camera was to be able to get an understanding of temperatures on the absorber and glazing of solar collectors with an eye toward making changes to the collector to improve heat output. This is something that is hard to do with ordinary instruments as its really helpful to know what's going on all over the absorber surface, not just in a few points. For my camera with 120 by 120 resolution its kind of like being able to place 14000 thermocouples on the absorber -- amazing!
This is an image of a backpass style solar air heating collector.
|Backpass style solar air heating collector.|
You can see immediately that there are places where the absorber is running much hotter -- these correspond to pockets of dead air where baffles are not working well. In these areas, the absorber just heats up until it can lose most of its heat out the glazing, which makes the collector less efficient.
I don't know of any other way to get this kind of detialed picture of what's going on.
Anyway, there is quite a bit more at the link above -- have a look.
Gary April 30, 2011