## Heat Transfer Rate

300°C air flows across a surface that is 45°C. What is the heat transfer rate over 4 m^2 of surface if the heat transfer coefficient is 80 W/[m^2(°C)]?

##
__
__**Hint**

**Hint**

$$$\dot{Q}=hA(\Delta T)$$$

where
$$h$$
is the convection heat transfer coefficient of the fluid,
$$A$$
is the convection surface area,
$$\Delta T$$
is the change in temperature.

##
__
__**Hint 2**

**Hint 2**

You don’t need to convert to Kelvin units.

Convection is heat transfer from one location to another through the movement of fluid. In this scenario, the air flow acts as a fluid. Thus, Newton's Law of Cooling:

$$$\dot{Q}=hA(\Delta T)$$$

where
$$h$$
is the convection heat transfer coefficient of the fluid,
$$A$$
is the convection surface area,
$$\Delta T$$
is the change in temperature.

Finally,

$$$\dot{Q}=80\frac{W}{m^2C}(4m^2)(300^{\circ}C-45^{\circ}C)=320(255)=81,600\:W$$$

81,600 W