The discussion centers on understanding the convective heat transfer rate using the equation q = hc A dT. The user calculated a heat transfer rate of q = 40 watts per second with values hc = 100, A = 0.01, and dT = 40. This indicates the amount of heat being transferred from a hot surface to the surrounding air. To determine how this affects the temperature increase of a given volume of air, one must also consider the mass and heat capacity of the air, as described by the equation MCp(dTa/dt) = hcA(Ts - Ta).
PREREQUISITESStudents in physics, engineers working with thermal systems, and anyone interested in the principles of heat transfer and thermodynamics.
hc is called the heat transfer coefficient. This equation tells you how much heat is passing through the surface into the air above. If the air is pretty well mixed and you are heating it from the surface, you can determine the rate of temperature rise of the air by also knowing the mass and heat capacity of the air: $$MC_p\frac{dT_a}{dt}=h_cA(T_s-T_a)$$dmehling said:Maybe I don't quite understand the point of the equation: q = hc A dT . I plugged in values of hc = 100, A = .01, dT = 40 and the answer was q = 40 w per second. I just want to know what that answer tells me about how much a given volume of air above a hot surface will increase over a given amount of time. Are there other values and factors that I need to know in order to figure this out.