# Heat loss with a diff.eq.

1. Feb 1, 2006

### TSN79

A room has a wall, and I'm trying to determine the heat loss from this room through this wall. My teacher set up these two equations for me;

$$m \cdot C_P \cdot {{dT_m } \over {dt}} = U \cdot A\left( {T_R - T_m } \right)$$

and

$$Q_P + \rho \cdot C_P \cdot \dot V\left( {T_R - T_{out} } \right) = U \cdot A\left( {T_R - T_{out} } \right)$$

I understand the first equaton to some extent, it will give me the wall temperature as a function of time once I solve it, but I don't really see what I'm to use the second one for...anyone?