Ideal Reheat Rankine Cycle

"Refer T-s plot to understand the cycle"

$UnitSystem SI Pa K J Mass    {Declaring unit system that we'll be using}
$TabStops 2 cm
{INPUTS}
f$ = 'Water'    {Water as working fluid}

T[1]=300 [K]
x[1]=0
h[1]=enthalpy(f$, T=T[1], x=x[1])
s[1]=entropy(f$, T=T[1], x=x[1])
P[1]=pressure(f$, T=T[1], x=x[1])

P[2]=15000000 [Pa]
P_2s=P[2]
s_2s=s[1]
h_2s=enthalpy(f$, P=P_2s, s=s_2s)
T_2s=temperature(f$, P=P_2s, s=s_2s)

eta_pump=(h_2s-h[1])/(h[2]-h[1])
eta_pump=0.85
{Now, we'll have h2 and p2}
T[2]=temperature(f$, h=h[2], P=P[2])
s[2]=entropy(f$, h=h[2], P=P[2])

P[3]=P[2]
x[3]=0
T[3]=temperature(f$, x=x[3], P=P[3])
h[3]=enthalpy(f$, x=x[3], T=T[3])
s[3]=entropy(f$, x=x[3], T=T[3])

P[4]=P[3]
T[4]=T[3]
x[4]=1
h[4]=enthalpy(f$, x=x[4], T=T[4])
s[4]=entropy(f$, T=T[4], x=x[4])

T[5]=873 [K]
P[5]=P[4]
h[5]=enthalpy(f$, P=P[5], T=T[5])
s[5]=entropy(f$, T=T[5], P=P[5])

s[5]=s_6s
P_6s=P[6]
P[6]=sqrt(P[8]*P[5])
P[8]=P[1]
P_8s=P[8]
h_6s=enthalpy(f$, P=P_6s, s=s_6s)

eta_turbine_hp=(h[5]-h[6])/(h[5]-h_6s)
eta_turbine_hp=0.87

{h6 and P6 are known}
T[6]=temperature(f$, P=P[6], h=h[6])
s[6]=entropy(f$, P=P[6], h=h[6])

P[7]=P[6]
T[7]=T[5]
h[7]=enthalpy(f$, T=T[7],P= P[7])
s[7]=entropy(f$, T=T[7], P=P[7])

s_8s=s[7]
{P8s and s8s are known}
h_8s=enthalpy(f$, s=s_8s, P=P_8s)

eta_turbine_lp=(h[7]-h[8])/(h[7]-h_8s)
eta_turbine_lp=0.85
{h8 will be calculated}
{h8 and P8 are known}
s[8]=entropy(f$, h=h[8], P=P[8])

T[8]=temperature(f$, h=h[8], P=P[8])


W_out=h[5]-h[6]+h[7]-h[8]
W_in=h[2]-h[1]
W_net=W_out-W_in
Q_in=h[5]-h[2]+h[7]-h[6]
eta=W_net/Q_in

Q_rejected=h[8]-h[1]
W_pump=W_in
W_turbine=W_out

 

NOTE: The 2-3-4-5 and 6-7 curves should be curves (along constant pressure) but are plotted by EES as straight lines. The points however are correct.

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