Basically I need heating element which can heat up small volume of air (lets say shoes box size) up to about 60 C degrees. I am going to use 25 V source supply with 2 A current.
What I thought about doing is:
Cp= 1.00 J/gK (air specific heat) q=1275g/m^3 (density of air) V=0.05m^3 (volume of air I need to heat up) T=333.15K - 293.15K = 40 K Lets assume room temperature is 20 C = 293.15 K
How much energy does it need to heat the 0.05m^3 volume of air:
U = cp * m * T = 1*1275*0.05*40 = 2550 J
If I want it to heat that kind of volume in 2 minutes how much watt do I need?
P=U/t = 2550/120 = 21.25 W
So I know how much watts should heating element produce, but what about ohms? Should I calculate Resistance needed by:
P=I^2 * R where I=2A, P=21.25W R=21.25/4 = 5.3125 Ohms
So my resistor should be 5.3125 ohms and handle AT LEAST 21.25 W (probably much more for safety?)
I am just asking if my calculations is correct as I don't know if i am going into the right direction and doesn't have anyone to ask about it.
Thanks for any help :)