Radiative Cooling
Most recent answer: 12/24/2012
Q:
Is it possible that the temperature of a car in conditions of calm air and clear sky falls below freezing even if the air temperature is above freezing, due to radiative loss of heat? I.e. may radiative dispersion of heat outweight the heat conduction from air to car?
- marco anderlini (age 36)
London, UK
- marco anderlini (age 36)
London, UK
A:
You don't specify how much the air temperature is above freezing, so the answer is yes. The radiative cooling effectively sees a sky that's a bit cooler than the air, since the atmosphere's greenhouse gases still leave some nearly transparent windows in the IR spectrum. Therefore the car partially equilibrates with the nearby air and partially with the cold distant sky. If the air is just above 0°C, the car can cool below 0°C.
A quick rough calculation suggests that the effect can be at least a few degrees.
Mike W.
A quick rough calculation suggests that the effect can be at least a few degrees.
Mike W.
(published on 12/24/2012)