Question

3. a) An electric water heater uses 5500 W (240 V) of electrical power. It has a capacity of 40 gallons (150 liters or 150 kg). If the initial temperature of the water in the water heater is 20° C, how long will it take to heat the water to a final temperature of 60° C at 100% efficiency? b) How long will it take to heat the water to a final temperature of 60°C at 80% efficiency? c)If electrical power costs 1 1 ¢/kW-hr, what will be cost be to heat the water (at 80% efficiency)? d) The water heater uses two identical resistors (both in parallel, receiving 240 V) to heat the water. Each resistor does half of the heating. What is the resistance (in ohms) of each resistor?

Answer 1

c'e 150 Kg nrat er Mond Poner 5500 xt NoN 4581.81 8182- S -1272727 hr 실 1:2727 hr g O lcv = 1,59 og hr . Ah 1000 3.71 995 Kh.h hW 5500