# Reflected temperature measurement

Discussion in 'General Electronics Chat' started by Shahniravk, Jul 13, 2009.

1. ### Shahniravk Thread Starter New Member

Jul 13, 2009
3
0
Hi! I want to measure the reflected temperature from the walls of a buildings in the presence of ambient temp. I think using an instrumentation ampl. in difference mode will work.can any1 suggest me a different scheme...?

2. ### Mike2545 Active Member

Mar 26, 2009
116
3
One of these would tell the temperature of the wall itself..

Jul 7, 2009
1,585
141
Do you mean you want to measure the infra-red radiation from the wall and deduce the wall's temperature? The instrument shown by the other poster is a commonly-available tool to do such measurements. Note that to be accurate, one must know the emissivity of the wall at the wavelengths of radiation being used (I think most inexpensive instruments assume the emissivity is around 0.95).

If that's not what you want, you'll have to be more descriptive.

4. ### DC_Kid Distinguished Member

Feb 25, 2008
641
9
there really is no such thing as "reflected temperature". temperature is a measurement of how much energy a mass has. given a mass that has homegeonous temp one can that use that in energy equations.

a cold mass can have equal, more, or less energy than a hot mass, etc. all depends on the mass itself, etc.

measuring a surface temp from a distance is possible, such as the temp gun shown.

measuring emr bouncing off a wall is a tad more difficult. emr bandwidth is fairly wide. the bandwidth is sliced up and given common names such as IR, UV, gamma, visible, etc, etc.

so, are you just wanting to measure temp of the surface, or are you asking about something else?? if ambient room temp is 100F and the wall is 110F, remote sensing with temp gun (like the one shown) might read something between 100-110, depending on how close the sensor is to the wall. for accurate surface measurement with ambient to worry about i would suggest a thermocouple on the surface and insulated from ambient.

or are you asking how to measure reflectivity of IR emr?? mylar is a good reflector of IR. solid black objects are not.