Question

A 0.145 m rigid tank initially contains refrigerant-134a at 1 MPa and 100 percent quality. The tank is connected by a valve to a supply line that carries refrigerant-134a ad.2 MPa and 36°C. Now the valre is opened, and the refrigerant is allowed to enter the tank. The valve is closed when it is observed that the tank contains saturated liquid atl.2 MPa. Determine (a) the mass of the refrigerant that has entered the tank 156.057g(Kound to three decimal places) and (b) the amount of heat transfer. Qin 560 Round to the nearest integer)

Answer 1

Given data V_1 = 0.145 m^3 P_1 = 1 mpa P_2 = 0.2 mpa Let denote the initial state of R-134a in tank denote the state of R-134 a in supply line denote the final state in tank So, initially P_1 = 1 mpa, V_1 = 0.134 m^3 & quality is 100% Means saturated vapour So, from property table of R-134a At P_1 = 1 mpa V_g = 0.02033 m^3/kg M_1 = V_1/V_g implies 0.145/0.02033 = M_1 = 7.13 kg \r\n and H_1 = M_1 h_g = 7.13 times 271.04 kj H_1 = 1932.51 kj Now, from property table of superheated state of R-134a At P_2 = 0.2 mpa & T_2 = 36 degrees c h_2 = 284.53 kj/kg Now, final state in tank is P_3 = 0.2 mpa & in saturated liquid So, at P_3 = 0.2 mpa V_f = 0.0007533 m^3/kg h_f = 38.43 kj/kg & V_3 = 0.145 m^3 [volume of tank in fixed] M_3 =