Problem

The key is recognizing that waste heat is energy that must be absorbed by flowing water—this is a heat capacity problem. The power (energy per unit time) dissipated equals the mass flow rate times the specific heat of water times the temperature change: $P = \dot{m} \cdot c \cdot \Delta T$. Rearrange to solve for the mass flow rate $\dot{m}$, using water's specific heat $c = 4186 \text{ J/(kg·°C)}$ and converting the power to watts.

The key is recognizing that waste heat is energy that must be absorbed by flowing water—this is a heat capacity problem. The power (energy per unit time) dissipated equals the mass flow rate times the specific heat of water times the temperature change: $P = \dot{m} \cdot c \cdot \Delta T$. Rearrange to solve for the mass flow rate $\dot{m}$, using water's specific heat $c = 4186 \text{ J/(kg·°C)}$ and converting the power to watts.