Water at 20 c flows from one large reservoir to another via a 60 cm id cast iron piping system when a ball valve near the end of the pipes is completely open. the goal is to have a minimum volumetric flow rate of 10 m3/s at all times. assume the pipe inlet and exit are well- rounded; the piping system consists of 120 total meters of pipe, six threaded 90 smooth-bend elbows, and two 45° threaded elbows. what elevation in the higher reservoir must be maintained to meet the minimum flow rate requirement?

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)?