A factory obtains water from a well $7m$ deep from the ground. Water is pumped at a constant rate of $800\frac{L}{h}$ to a vented storage tank to maintain a water level of $50m$ above the ground. There is a heater that provides $20000Bt\frac{u}{h}$ to prevent the water from freezing and there is a total loss of heat from the system at a rate of $15000Bt\frac{u}{h}.$ The temperature of water is $2C$ in the well and it increases to $5C$ in the storage tank. Find the required power in horsepower to be supplied by the pump if $55\%$ of its power is dissipated as heat to the atmosphere.