Question

Water is boiled in a pan covered with a poorly fitting lid at location where the pressure is 85.4 kPa. Rate of heat supplied by the pan is 3.342-kW and it runs with 56.706 % efficiency. How long will it take to boil 1.328 kg of water, in minutes?

Answer 1

We have heat of vaporization at 85.4KPa(local pressure) as 2269kj/kg

So, energy required is given by

so, we have

Here f=.56 and E=3.342kW

So,