Chapter 8, Problem 8.17P

Referring to the reversible heat pump cycle shown in the figure, p₁ = 14.7 lb/in², p = 41.5 lb/in², v₁ = 12.6 ft³/lb, v4 = 6.0 ft³/lb, and the gas is air obeying the ideal gas model. Step 1 Determine TH, in °R, and the coefficient of performance. Determine TH, in °R. TH= i P4 ºR P1 V4 VI 3 Tμ V

... .. Two Carnot refrigeration A and B operate in series. The refrigerator A absorbs energy at rate Q1(kJ/s) from a body at temperature 300K, and reject energy as heat to a body at temperature T. The refrigerator B absorbs the same quantity of energy which is rejected by refrigerator A from a body at temperature T, and rejects energy as heat to a body at temperature 1200K. If both refrigerators have the same C.O.P, then work input to refrigerator A is 1.5Q1 O Other O 1.4Q1 O 1.1Q1 O 1.3Q1 O

Q1. Solve all parts Depicted in Fig. Q1 is an irreversible refrigerator whose compressor is powered by a reversible heat engine that operates between temperature extremes Thot = 473K and cold = 293 K. The refrigerator depicted uses a dichlorodifluoromethane refrigerant (Refrigerant 12) circulating by means of the compressor at mass flow rate = 0.15 kg/s. The other components of the refrigerator are two heat exchangers in the form of an evaporator and a condenser, and a throttle valve. Information recorded at the state points depicted in Fig. Q1 is as follows: State point 1: dryness fraction x₁ = 1 and temperature t₁ = 15 °C. State point 2: dryness fraction x2 = 0 and temperature t₂ = 15°C. State point 3: wet vapour at temperature t₁ = -20°C. State point 4: wet vapour at temperature t₁ = -20°C. (a) Determine the thermal efficiency NR of the reversible heat engine depicted in Fig. Q1, and consequently determine power -W4-1 supplied to the compressor given that the rate of heat supplied…