Question

An electric heater draws 5 kW of power for continuous hot water generation in an
industry. How much quantity of water in litres per min can be heated from 30oC to
85oC

Answer 1

Explanation:

mass (m) = density*volume/sec

Cp of water = 4.2 kj/kg°c

density of water = 1000 kg/m^3

power for heating = m*Cp of water*∆t

5*10^3 = 1000*V*4.2*10^3*(85-30)

volume/sec = 5/(1000*4.2*55)

= 2.164*10^-5 m^3/sec

= 2.164*10^-5*10^3*60 lt/min

= 1.2987 litres/min