Light bulbs are rated by their power consumption in watts (w). electricity is sold in units of energy, which is power multiplied by time. electricity costs vary widely across the united states and are on the order of 0.06-0.23$/kw-hr for residential customers. create a spreadsheet that utilizes electricity costs and the number of hours per day that a light bulbs is on as input variables. then calculate the annual cost to operate a 60-w, 75-w, and 100-w incandescent bulb and a 15-w compact fluorescent bulb. assuming the average household operates six 60-w, four 75-w, and two 100-w incandescent bulbs for 6 hours a dday. how much money can they save in year by changing all the bulbs to compact fluorescent?

Give heat transfer applications for the following, (i) gas turbines (propulsion) ) gas turbines (power generation). (iii) steam turbines. (iv) combined heat and power (chp). (v) automotive engines

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?

How much power could a wind turbine produce if it had the following specifications? cp = 0.45 -d=1.2kg/m3 d=50m v 5m/s