Asimplified problem for a hydro plant involves a penstock of length 2500 ft, the velocity of the penstock is 6 ft/sec, the penstock area is 100 ft2, the surge tank area is proposed to be 2000 ft2, and the friction head loss in the pen stock is 3 ft. determine the approximate maximum pressure surge in the surge tank and time from beginning of flow until maximum surge if the gate valve is suddenly closed.

An external consultant recommends that a plant installs a bank of capacitors for power factor correction. this will reduce the peak electrical demand charges by an average of 93 kw every month. the plant current pays $13 per kw in peak demand charges. the capacitor bank will include 223 kw of fixed capacitors, and 183 of variable capacitors. the fixed capacitors cost $59 per kw, and the variable capacitors will cost $65 per kw. the consultant charges 21% of the equipment costs to install the capacitors. because this project will reduce the demand for the electric utility, they are prepared to provide a one-time rebate of $42 per kw of reduced demand. what is the simple payback period for this project (in years)?