Using the setup of the previous post
but with no fan and no shadow dot used the following results have been obtained.
(x-axis is in seconds from start of test - many tests were done and recorded over about 12 hours - the main problem is trying to keep ambient constant or at least clear of low frequency noise)
Detrended by the air gap temperature between double glazed and single IR window the plot shows that with Warm source in place Hot body is 0.3°C hotter than when ambient source is in place
This shows a continuous recording of the warm source temperature - the Red line indicates that the source is facing the IR windows - the dotted lines indicate that it has been placed away from the IR windows. No attempt has been made to stabilise the warm source temperature - It simply has to be above ambient and below the hot plate temperature.
This plot shows the detrended temperature of the air between the double glazed IR window
This plot shows the air between the double glazed window and the isolated IR window. Note that it shows no sign of being warmed by the warm source. The trend is because of ambient changes. This trend was removed from the "detrended" plots
It should be noted that the radiation from the warm plate has to pass through 3 layers of poly film to reach the hot plate. In a previous post
I showed that this food wrap (LDPE) is not 100% transparent to IR.
Again I am certain that the hot body temperature increase is caused by the IR from the warm source.
Again criticism of the experiment is welcomed!
Full recorded data is available.
other posts on this subject: