(4) No pressure losses in the heat exchanger and in the pipe arrangement.
(5) Isoentropic changes occur in the turbine.
(6) Isoentropic changes occur in the pump.
(7) Isothermal changes occur in the diffuser.
(8) Working fluid is saturated at the outlets of the absorber (lower pressure condenser) and condenser (higher pressure condenser).
In the following, the calculation procedure is shown.
1) Input the condition of turbine inlet vapour (P13, T13, X13), vapour liquid separator temperature (T1, T2, T5), absorber (lower pressure condenser) outlet temperature (T17) and condenser (higher-pressure condenser) outlet temperature (T8).
2) Calculating the pressure (in other words, intermediate pressure of cycle) P1 of vapour liquid separator from temperature and concentration T8 and X8 (= X13) of condenser (higher-pressure condenser) outlet.
3) Calculating the liquid concentration X1 and the vapour concentration X5 from assuming the concentration X1 in two-phase condition of vapour liquid separator inlet and using the intermediate pressure P1 obtained by 2) and T1.
4) Calculating the vapour liquid ratio at vapour liquid separator from X1 and X5 and the flow ratio after separation from vapour liquid ratio.
5) Calculating the flow rate from the relation of concentration at each point.
6) Calculate condition value of each point (point 1, 2, 3, 4, 16, 17, 18, 19, 20, 21 and 22) within the loop of absorption-distillation-condensation system from heat balance and mass balance.
7) Repeating the calculation of step 3)〜6) by assuming X1 until temperature T22 agree with T1.
8) Decision the condition of each point as the heat and mass balance is completed when temperature of vapour liquid separator T1 = T22.
9) Calculating the turbine output WTBN, the boiler input heat QBLR and cycle efficiency η from the condition of each point.
Table 1 shows the calculation condition.
4. Results and discussion
Figure 3 shows the cycle efficiency for various separator temperatures as a function of boiler outlet temperatures. Separator temperature effects significantly the cycle efficiency. As a matter of fact, the cycle efficiency increases with the increase of boiler outlet temperature.
Figure 4 shows the cycle efficiency for cooling water temperature at absorber and condenser for each ammonia mass fraction of turbine inlet vapour. The cycle efficiency decreases with identical cooling condition in according with the large ammonia concentration of turbine inlet vapour. The pressure of vapour liquid separator becomes higher as the condenser outlet ammonia concentrations become higher. Absorber pressure is high because of the high ammonia concentration in the solution.
Figure 4 cycle efficiency for separator temperature.
Figure 4 Cycle efficiency for cooling temperature.
