A heat exchanger produces dry steam at 100 degree Celsius from feed water at 35 degree Celsius at a rate of 2kgs^-1. the heat exchanger receives heat energy at a rate of 680 kW from the fuel used. the specific heat capacity of water is 4187 Jkg^-1K^-1 and the specific latent heat of vaporization is 2257 Jkg^-1

determine the heat energy received per kilogram of steam produced

determine the output power of the heat exchanger and its thermal efficiency.