clear ; clc; // Example 24.3 printf('Example 24.3\n\n'); //page no. 728 // Solution Fig. E24.3 // Given m_CO2 = 10 ;// mass of CO2 - [lb] Ti_CO2 = 80 ;// Initial temperature of CO2 - [degree F] Vi = 4.0 ;// Initial volume of CO2-[cubic feet] f_CO2 = 40/100 ;// Fraction of CO2 that convert to liquid finally s_Vi = Vi /m_CO2 ;// Initial specific volume of CO2 - [cubic feet/lb] s_Vf = s_Vi ;// Constant volume -[cubic feet/lb] // Use the CO2 chart in Appendix J to necessary data, according to book it is // CO2 is gas at start of process and reference state for the CO2 chart is -40 degree F , saturated liquid // From chart Pi = 300 ;// Intial pressure - [psia] del_Hi = 160 ;// Intial change in specific enthalpy - [Btu/lb] // Now again use chart to get fnal condition fixed by constant volume line and quality 0.6 , according to book it is del_Hf = 81 ;// Final change in specific enthalpy - [Btu/lb] Pf = 140 ;//Final pressure - [psia] // Use conditions given in problem ( W= 0 ,since volume is constant ,therefore del_PE and del_KE =0 ),simplifing the energy balance equation we get Q = del_H - del_(PV) // Analysing the given conditions dof of system = 0 , with 1 eqn. and 1 unknown Q Q = ((del_Hf - del_Hi) - (Pf * s_Vf * 144/778.2 - Pi * s_Vi * 144/778.2))*m_CO2 ;// Heat removed from the extinguisher -[Btu] printf(' Heat removed from the extinguisher is %i Btu .\n',Q);