Radiator Thermal Emissivity
Most recent answer: 05/22/2013
- kurt (age 40)
Australia
Although this has the general sound of a homework problem, which we would not answer, it does raise some issues worth discussing. The calculation called for is simple enough, since you just use that the thermal emission is proportional to T4, where T is the absolute temperature. More importantly, the answer you get by setting the problem up that way has very little to do with the real world. The main complication is that radiators lose a great deal of heat by convection, rather than by thermal radiation. Another complication is that emissivity of paints can be a strong function of frequency. It makes little sense to characterize the emissivity for broad-spectrum thermal radiation by a single number, especially one based on visible frequencies, which one hopes the radiator is not emitting.
Mike W. (posted without checking until Lee gets back)
(published on 05/22/2013)