The equivalent evaporation (kg/hr) of a boiler producing 2000 kg/hr of steam with enthalpy content of 2426 kJ/kg from feed water at temperature 40°C (liquid enthalpy =168 kJ/kg) is (enthalpy of vaporization of water at 100°C = 2258 kJ/kg)

In the vicinity of the triple point, the vapour pressures of liquid and solid ammonia are respectively given by ln P= 15.16 – 3063/T and In P= 18.70 – 3754/T where P is in atmospheric and T is in kelvin. What is the temperature at the triple point?

In the figure shown, the system is a pure substance kept in a piston-cyllnder arrangement. The system is initially a twophase mixture containing 1 kg of liquid and 0.03 kg of vapour at a pressure of 100 kPa. Initially, the piston rests on a set of stops, a shown in the figure. A pressure of 200 kPa is required to exactly balance the weight of the piston and the outside atmospheric pressure. Heat transfer takes place into the system until its volume increases by 50%. Heat transfer to the system occurs in such a manner that the piston, where it is allowed to move, does so in a very slow (quasi-Static/quasi-equilibrium) process. The thermal reservoir from which heat is transferred to the system has a temperature of 400°C. Average temperature of the system boundary can be taken as 175°C. The heat transfer to the system is 1 kJ, during which its entropy increases by 10 J/K. Specific volumes of liquid (vf) and vapour (vg) phases, as well as values of saturation temperatures, are given in the table below.

Pressure	Saturation	Vf ( m3/Kg )		Vg( m3/Kg )
100	100	0.001		0.1
200	200	0.0015		0.002

The work done by the system during the process is

Boiler rating is usually defined in terms of

A vessel of volume 1.0 m³ contains a mixture of liquid water and steam in equilibrium at 1.0 bar. Given that 90% of the volume is occupied by the steam, find the fraction of the mixture. Assume at 1.0 bar, v_f = 0.001 m³/kg and v_g = 1.7 m³/kg.