Problem $2-33($modified$),$ Davis and Cornwell, Introduction to Environmental Engineering,

$6$th Ed$.$:

The discharge pipe from a sump pump in the dry well of a sewage lift station did not drain

properly, and the water at the discharge end of the pipe froze. A hole has been drilled into the

ice, and a $250-W$ electric heater has been inserted in the hole to melt the ice. Assume all the

heat goes into melting the ice.

a$.$ Is the system an open system or a closed system?

b$.$ Construct an energy balance for the system.

c$.$ If the discharge pipe contains $3\mathrm{.}75kg$ of ice, how long will it take to melt the ice?