test/bug567/combinedcycle_fprops.a4c

(*	ASCEND modelling environment
	Copyright (C) 2010 Carnegie Mellon University

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2, or (at your option)
	any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.
	
	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*)(*
	This file contains a model of a combined-cycle power station, with
	a gas turbine (Brayton) cycle running as the 'topping' cycle and a steam
	turbine (Rankine) cycle running as the 'bottoming' cycle. Initially the 
	model is being based on Example 9.13 from Moran & Shapiro, 'Fundamentals of
	Engineering Thermodynamics', 4th Ed, Wiley, 2000.

	See also Example 10-9 from the book Çengel & Boles 
	'Thermodynamcs: An Engineering Approach, 6th Ed, McGraw-Hill, 2008.

	This file was based on models/johnpye/combinedcycle.a4c which originally
	made use of the external library 'freesteam' for calculation of steam
	properties in the bottoming cycle. This version has been modified to make
	use of FPROPS for the property calculations, allowing the model to be
	adapted for use with various different fluids.

	Author: John Pye
*)
REQUIRE "test/bug567/rankine_fprops.a4c";
REQUIRE "test/bug567/brayton.a4c";

MODEL air_stream_heat_exchanger REFINES air_equipment;
	inlet_cold, outlet_cold IS_A stream_node;
	inlet.p, outlet.p ARE_THE_SAME;
	inlet_cold.p, outlet_cold.p ARE_THE_SAME;
	inlet_cold.mdot, outlet_cold.mdot ARE_THE_SAME;
	inlet_cold.cd, outlet_cold.cd ARE_THE_SAME;

	mdot_cold ALIASES inlet_cold.mdot;
	cd_cold ALIASES inlet_cold.cd;

	(* some very simplistics checks that temperatures are feasible: not totally safe! *)
	DT_1, DT_2 IS_A delta_temperature;
	DT_1 = inlet.T - outlet_cold.T;
	DT_2 = outlet.T - inlet_cold.T;	

	(* some intermediate temperatures for plotting *)
	n IS_A integer_constant;
	n :== 20;
	H[0..n] IS_A air_node;
	H[0..n].p, inlet.p ARE_THE_SAME;
	H[0..n].mdot, inlet.mdot ARE_THE_SAME;
	H[0].h, inlet.h ARE_THE_SAME;
	H[n].h, outlet.h ARE_THE_SAME;
	FOR i IN [1..n-1] CREATE
		H[i].h = H[0].h + (H[n].h - H[0].h)/n * i;
	END FOR;

	Qdot IS_A energy_rate;
	(* Strange, but the following form solves better than the obvious form, 
	Could maybe be something to do with scaling. *)
	outlet.h - inlet.h = Qdot/inlet.mdot;
	outlet_cold.h = inlet_cold.h - Qdot/inlet_cold.mdot;
METHODS
METHOD default_self;
	RUN inlet_cold.default_self;
	RUN outlet_cold.default_self;
	DT_1.lower_bound := 0 {K};
	DT_2.lower_bound := 0 {K};
END default_self;
END air_stream_heat_exchanger;


MODEL air_stream_heat_exchanger_test REFINES air_stream_heat_exchanger;
	cd_cold.component :== 'water';
METHODS
METHOD on_load;
	RUN default_self;
	FIX inlet_cold.p; inlet_cold.p := 50 {bar};
	FIX inlet_cold.h; inlet_cold.h := 200 {kJ/kg};
	FIX inlet.p; inlet.p := 1 {bar};
	FIX inlet.T; inlet.T := 700 {K};
	FIX mdot; mdot := 1 {kg/s};
	FIX mdot_cold; mdot_cold := 0.1 {kg/s};
	FIX Qdot; Qdot := 10 {kW};
END on_load;
END air_stream_heat_exchanger_test;

(* --- whole cycle models --- *)

MODEL combinedcycle_fprops_common;
	(* define the blocks *)
	GC IS_A compressor;
	BU IS_A combustor;
	GT IS_A gas_turbine;
	HE IS_A air_stream_heat_exchanger;
	DI IS_A dissipator;
	TU IS_A turbine_simple;
	CO IS_A condenser_simple;
	PU IS_A pump_simple;

	(* wire up the model *)
	GC.outlet, BU.inlet ARE_THE_SAME;
	BU.outlet, GT.inlet ARE_THE_SAME;
	GT.outlet, HE.inlet ARE_THE_SAME;
	HE.outlet, DI.inlet ARE_THE_SAME;
	DI.outlet, GC.inlet ARE_THE_SAME;

	HE.outlet_cold, TU.inlet ARE_THE_SAME;
	TU.outlet, CO.inlet ARE_THE_SAME;
	CO.outlet, PU.inlet ARE_THE_SAME;
	PU.outlet, HE.inlet_cold ARE_THE_SAME;

	cd_rankine ALIASES TU.inlet.cd;

	Wdot, Wdot_gas, Wdot_vap IS_A energy_rate;
	Wdot_gas = GC.Wdot + GT.Wdot;
	Wdot_vap = TU.Wdot + PU.Wdot;
	Wdot = Wdot_gas + Wdot_vap;
	
	braytonpowerfraction IS_A fraction;
	braytonpowerfraction = Wdot_gas / Wdot;

	Qdot_H ALIASES BU.Qdot;
	Qdot_HE ALIASES HE.Qdot;
	Qdot_DI ALIASES DI.Qdot;
	
	eta IS_A fraction;
	eta = Wdot / Qdot_H;

	massflowratio IS_A factor;
	massflowratio = TU.mdot / GT.mdot;

	braytonpressureratio IS_A positive_factor;
	braytonpressureratio * GC.inlet.p = GC.outlet.p;

METHODS
METHOD default_self;
	RUN TU.default_self;
	RUN PU.default_self;
	RUN CO.default_self;
	RUN HE.default_self;
END default_self;
METHOD specify;
	(* these values should be independent of the fluid we choose to use *)
	FIX GC.eta; GC.eta := 0.84;
	FIX GT.eta; GT.eta := 0.88;
	FIX TU.eta; TU.eta := 0.85;
	FIX PU.eta; PU.eta := 0.8;
	FIX CO.outlet.x; CO.outlet.x := 1e-6;
	FIX BU.eta; BU.eta := 1;
END specify;
END combinedcycle_fprops_common;


MODEL combinedcycle_toluene REFINES combinedcycle_fprops_common;
	TU.inlet.cd.component :== 'toluene';
	HE.outlet.T = PU.outlet.T + 40 {K};
	HE.outlet_cold.T = GT.outlet.T - 20 {K};
	Tmax_rankine ALIASES HE.outlet_cold.T;
METHODS
METHOD default_self;
	RUN combinedcycle_fprops_common::default_self;
	(* starting guess, for easy solving *)
	HE.outlet_cold.h := 400 {kJ/kg};
	CO.outlet.h := 400 {kJ/kg};
END default_self;
METHOD on_load;
	RUN ClearAll;
	RUN default_self;
	RUN combinedcycle_fprops_common::specify;
	FIX Wdot; Wdot := 100 {MW};
	
	(* ambient conditions *)
	FIX GC.inlet.T, GC.inlet.p;
	GC.inlet.T := 30 {K} + 273.15 {K};
	GC.inlet.p := 1 {bar};

	(* Brayton parameters *)
	FIX braytonpressureratio; braytonpressureratio := 10.9; (* optimise this *)
	FIX BU.outlet.T; BU.outlet.T := 970 {K} + 273.15 {K};

	(* Rankine cycle condenser *)
	CO.outlet.p := 8 {kPa};
	FIX CO.outlet.T; CO.outlet.T := 40 {K} + 273.15 {K};
	FIX TU.inlet.p; TU.inlet.p := 150 {bar};

	(* optimisable *)

	(* heat exchange cycle *)
(*	FIX HE.outlet.T; HE.outlet.T := 60 {K} + 273.15 {K};
	FIX HE.outlet_cold.T; HE.outlet_cold.T := 470 {K} + 273.15 {K};
*)
	SOLVER QRSlv;
	OPTION convopt 'RELNOM_SCALE';
END on_load;
END combinedcycle_toluene;


MODEL combinedcycle_water REFINES combinedcycle_fprops_common;
	TU.inlet.cd.component :== 'water';
	x_turb_out ALIASES TU.outlet.x;
	(* the difference values in these formula have to be corrected by looking
	at the heat exchanger temperature profiles; haven't thoroughly modelled
	this bit yet! *)
	HE.outlet.T = PU.outlet.T + 130 {K};
	HE.outlet_cold.T = GT.outlet.T - 20 {K};
METHODS
METHOD default_self;
	RUN combinedcycle_fprops_common::default_self;
	(* starting guess, for easy solving *)
	HE.outlet_cold.h := 3000 {kJ/kg};
	TU.inlet.h := 4000 {kJ/kg};
END default_self;
METHOD on_load;
	RUN ClearAll;
	RUN default_self;
	RUN combinedcycle_fprops_common::specify;
	FIX Wdot; Wdot := 100 {MW};

	(* ambient conditions *)
	FIX GC.inlet.T, GC.inlet.p;
	GC.inlet.T := 30 {K} + 273.15 {K};
	GC.inlet.p := 1 {bar};

	(* Brayton parameters *)
	FIX braytonpressureratio; braytonpressureratio := 7.2; (* optimise this *)
	FIX BU.outlet.T; BU.outlet.T := 970 {K} + 273.15 {K};

	(* Rankine cycle condenser *)
	CO.outlet.p := 8 {kPa};
	FIX CO.outlet.T; CO.outlet.T := 40 {K} + 273.15 {K};
	FIX TU.inlet.p; TU.inlet.p := 150 {bar};

	SOLVER QRSlv;
	OPTION convopt 'RELNOM_SCALE';
END on_load;
METHOD set_x_limit;
	FREE PU.outlet.p;
	PU.outlet.p.upper_bound := 150 {bar};
	FIX TU.outlet.x; TU.outlet.x := 0.9;
END set_x_limit;

END combinedcycle_water;

MODEL combinedcycle_water_opt REFINES combinedcycle_water;
	MAXIMIZE eta;
METHODS
METHOD on_load;
	RUN combinedcycle_water::on_load;
	braytonpressureratio.lower_bound := 8;
	braytonpressureratio.upper_bound := 20;
END on_load;
END combinedcycle_water_opt;


MODEL combinedcycle_ammonia REFINES combinedcycle_fprops_common;
	TU.inlet.cd.component :== 'ammonia';
	HE.outlet.T = PU.outlet.T + 15 {K};
	HE.outlet_cold.T = GT.outlet.T - 12 {K};
METHODS
METHOD default_self;
	RUN combinedcycle_fprops_common::default_self;
	(* starting guess, for easy solving *)
	HE.outlet_cold.h := 400 {kJ/kg};
	CO.outlet.h := 400 {kJ/kg};
END default_self;
METHOD on_load;
	RUN ClearAll;
	RUN default_self;
	RUN combinedcycle_fprops_common::specify;
	FIX Wdot; Wdot := 100 {MW};
	
	(* ambient conditions *)
	FIX GC.inlet.T, GC.inlet.p;
	GC.inlet.T := 30 {K} + 273.15 {K};
	GC.inlet.p := 1 {bar};

	(* Brayton parameters *)
	FIX braytonpressureratio; braytonpressureratio := 11.2; (* optimise this *)
	FIX BU.outlet.T; BU.outlet.T := 970 {K} + 273.15 {K};

	(* Rankine cycle condenser *)
	CO.outlet.p := 8 {kPa};
	FIX CO.outlet.T; CO.outlet.T := 40 {K} + 273.15 {K};
	FIX TU.inlet.p; TU.inlet.p := 150 {bar};

	SOLVER QRSlv;
	OPTION convopt 'RELNOM_SCALE';
END on_load;
END combinedcycle_ammonia;

(*
the combinedcycle_co2 model is removed, because it wasn't viable due to the
location of the CO2 critical point.
*)
1	(* ASCEND modelling environment
2	Copyright (C) 2010 Carnegie Mellon University
3
4	This program is free software; you can redistribute it and/or modify
5	it under the terms of the GNU General Public License as published by
6	the Free Software Foundation; either version 2, or (at your option)
7	any later version.
8
9	This program is distributed in the hope that it will be useful,
10	but WITHOUT ANY WARRANTY; without even the implied warranty of
11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12	GNU General Public License for more details.
13
14	You should have received a copy of the GNU General Public License
15	along with this program. If not, see <http://www.gnu.org/licenses/>.
16	)(
17	This file contains a model of a combined-cycle power station, with
18	a gas turbine (Brayton) cycle running as the 'topping' cycle and a steam
19	turbine (Rankine) cycle running as the 'bottoming' cycle. Initially the
20	model is being based on Example 9.13 from Moran & Shapiro, 'Fundamentals of
21	Engineering Thermodynamics', 4th Ed, Wiley, 2000.
22
23	See also Example 10-9 from the book Çengel & Boles
24	'Thermodynamcs: An Engineering Approach, 6th Ed, McGraw-Hill, 2008.
25
26	This file was based on models/johnpye/combinedcycle.a4c which originally
27	made use of the external library 'freesteam' for calculation of steam
28	properties in the bottoming cycle. This version has been modified to make
29	use of FPROPS for the property calculations, allowing the model to be
30	adapted for use with various different fluids.
31
32	Author: John Pye
33	*)
34	REQUIRE "test/bug567/rankine_fprops.a4c";
35	REQUIRE "test/bug567/brayton.a4c";
36
37	MODEL air_stream_heat_exchanger REFINES air_equipment;
38	inlet_cold, outlet_cold IS_A stream_node;
39	inlet.p, outlet.p ARE_THE_SAME;
40	inlet_cold.p, outlet_cold.p ARE_THE_SAME;
41	inlet_cold.mdot, outlet_cold.mdot ARE_THE_SAME;
42	inlet_cold.cd, outlet_cold.cd ARE_THE_SAME;
43
44	mdot_cold ALIASES inlet_cold.mdot;
45	cd_cold ALIASES inlet_cold.cd;
46
47	(* some very simplistics checks that temperatures are feasible: not totally safe! *)
48	DT_1, DT_2 IS_A delta_temperature;
49	DT_1 = inlet.T - outlet_cold.T;
50	DT_2 = outlet.T - inlet_cold.T;
51
52	(* some intermediate temperatures for plotting *)
53	n IS_A integer_constant;
54	n :== 20;
55	H[0..n] IS_A air_node;
56	H[0..n].p, inlet.p ARE_THE_SAME;
57	H[0..n].mdot, inlet.mdot ARE_THE_SAME;
58	H[0].h, inlet.h ARE_THE_SAME;
59	H[n].h, outlet.h ARE_THE_SAME;
60	FOR i IN [1..n-1] CREATE
61	H[i].h = H[0].h + (H[n].h - H[0].h)/n * i;
62	END FOR;
63
64	Qdot IS_A energy_rate;
65	(* Strange, but the following form solves better than the obvious form,
66	Could maybe be something to do with scaling. *)
67	outlet.h - inlet.h = Qdot/inlet.mdot;
68	outlet_cold.h = inlet_cold.h - Qdot/inlet_cold.mdot;
69	METHODS
70	METHOD default_self;
71	RUN inlet_cold.default_self;
72	RUN outlet_cold.default_self;
73	DT_1.lower_bound := 0 {K};
74	DT_2.lower_bound := 0 {K};
75	END default_self;
76	END air_stream_heat_exchanger;
77
78
79	MODEL air_stream_heat_exchanger_test REFINES air_stream_heat_exchanger;
80	cd_cold.component :== 'water';
81	METHODS
82	METHOD on_load;
83	RUN default_self;
84	FIX inlet_cold.p; inlet_cold.p := 50 {bar};
85	FIX inlet_cold.h; inlet_cold.h := 200 {kJ/kg};
86	FIX inlet.p; inlet.p := 1 {bar};
87	FIX inlet.T; inlet.T := 700 {K};
88	FIX mdot; mdot := 1 {kg/s};
89	FIX mdot_cold; mdot_cold := 0.1 {kg/s};
90	FIX Qdot; Qdot := 10 {kW};
91	END on_load;
92	END air_stream_heat_exchanger_test;
93
94	(* --- whole cycle models --- *)
95
96	MODEL combinedcycle_fprops_common;
97	(* define the blocks *)
98	GC IS_A compressor;
99	BU IS_A combustor;
100	GT IS_A gas_turbine;
101	HE IS_A air_stream_heat_exchanger;
102	DI IS_A dissipator;
103	TU IS_A turbine_simple;
104	CO IS_A condenser_simple;
105	PU IS_A pump_simple;
106
107	(* wire up the model *)
108	GC.outlet, BU.inlet ARE_THE_SAME;
109	BU.outlet, GT.inlet ARE_THE_SAME;
110	GT.outlet, HE.inlet ARE_THE_SAME;
111	HE.outlet, DI.inlet ARE_THE_SAME;
112	DI.outlet, GC.inlet ARE_THE_SAME;
113
114	HE.outlet_cold, TU.inlet ARE_THE_SAME;
115	TU.outlet, CO.inlet ARE_THE_SAME;
116	CO.outlet, PU.inlet ARE_THE_SAME;
117	PU.outlet, HE.inlet_cold ARE_THE_SAME;
118
119	cd_rankine ALIASES TU.inlet.cd;
120
121	Wdot, Wdot_gas, Wdot_vap IS_A energy_rate;
122	Wdot_gas = GC.Wdot + GT.Wdot;
123	Wdot_vap = TU.Wdot + PU.Wdot;
124	Wdot = Wdot_gas + Wdot_vap;
125
126	braytonpowerfraction IS_A fraction;
127	braytonpowerfraction = Wdot_gas / Wdot;
128
129	Qdot_H ALIASES BU.Qdot;
130	Qdot_HE ALIASES HE.Qdot;
131	Qdot_DI ALIASES DI.Qdot;
132
133	eta IS_A fraction;
134	eta = Wdot / Qdot_H;
135
136	massflowratio IS_A factor;
137	massflowratio = TU.mdot / GT.mdot;
138
139	braytonpressureratio IS_A positive_factor;
140	braytonpressureratio * GC.inlet.p = GC.outlet.p;
141
142	METHODS
143	METHOD default_self;
144	RUN TU.default_self;
145	RUN PU.default_self;
146	RUN CO.default_self;
147	RUN HE.default_self;
148	END default_self;
149	METHOD specify;
150	(* these values should be independent of the fluid we choose to use *)
151	FIX GC.eta; GC.eta := 0.84;
152	FIX GT.eta; GT.eta := 0.88;
153	FIX TU.eta; TU.eta := 0.85;
154	FIX PU.eta; PU.eta := 0.8;
155	FIX CO.outlet.x; CO.outlet.x := 1e-6;
156	FIX BU.eta; BU.eta := 1;
157	END specify;
158	END combinedcycle_fprops_common;
159
160
161	MODEL combinedcycle_toluene REFINES combinedcycle_fprops_common;
162	TU.inlet.cd.component :== 'toluene';
163	HE.outlet.T = PU.outlet.T + 40 {K};
164	HE.outlet_cold.T = GT.outlet.T - 20 {K};
165	Tmax_rankine ALIASES HE.outlet_cold.T;
166	METHODS
167	METHOD default_self;
168	RUN combinedcycle_fprops_common::default_self;
169	(* starting guess, for easy solving *)
170	HE.outlet_cold.h := 400 {kJ/kg};
171	CO.outlet.h := 400 {kJ/kg};
172	END default_self;
173	METHOD on_load;
174	RUN ClearAll;
175	RUN default_self;
176	RUN combinedcycle_fprops_common::specify;
177	FIX Wdot; Wdot := 100 {MW};
178
179	(* ambient conditions *)
180	FIX GC.inlet.T, GC.inlet.p;
181	GC.inlet.T := 30 {K} + 273.15 {K};
182	GC.inlet.p := 1 {bar};
183
184	(* Brayton parameters *)
185	FIX braytonpressureratio; braytonpressureratio := 10.9; (* optimise this *)
186	FIX BU.outlet.T; BU.outlet.T := 970 {K} + 273.15 {K};
187
188	(* Rankine cycle condenser *)
189	CO.outlet.p := 8 {kPa};
190	FIX CO.outlet.T; CO.outlet.T := 40 {K} + 273.15 {K};
191	FIX TU.inlet.p; TU.inlet.p := 150 {bar};
192
193	(* optimisable *)
194
195	(* heat exchange cycle *)
196	(* FIX HE.outlet.T; HE.outlet.T := 60 {K} + 273.15 {K};
197	FIX HE.outlet_cold.T; HE.outlet_cold.T := 470 {K} + 273.15 {K};
198	*)
199	SOLVER QRSlv;
200	OPTION convopt 'RELNOM_SCALE';
201	END on_load;
202	END combinedcycle_toluene;
203
204
205	MODEL combinedcycle_water REFINES combinedcycle_fprops_common;
206	TU.inlet.cd.component :== 'water';
207	x_turb_out ALIASES TU.outlet.x;
208	(* the difference values in these formula have to be corrected by looking
209	at the heat exchanger temperature profiles; haven't thoroughly modelled
210	this bit yet! *)
211	HE.outlet.T = PU.outlet.T + 130 {K};
212	HE.outlet_cold.T = GT.outlet.T - 20 {K};
213	METHODS
214	METHOD default_self;
215	RUN combinedcycle_fprops_common::default_self;
216	(* starting guess, for easy solving *)
217	HE.outlet_cold.h := 3000 {kJ/kg};
218	TU.inlet.h := 4000 {kJ/kg};
219	END default_self;
220	METHOD on_load;
221	RUN ClearAll;
222	RUN default_self;
223	RUN combinedcycle_fprops_common::specify;
224	FIX Wdot; Wdot := 100 {MW};
225
226	(* ambient conditions *)
227	FIX GC.inlet.T, GC.inlet.p;
228	GC.inlet.T := 30 {K} + 273.15 {K};
229	GC.inlet.p := 1 {bar};
230
231	(* Brayton parameters *)
232	FIX braytonpressureratio; braytonpressureratio := 7.2; (* optimise this *)
233	FIX BU.outlet.T; BU.outlet.T := 970 {K} + 273.15 {K};
234
235	(* Rankine cycle condenser *)
236	CO.outlet.p := 8 {kPa};
237	FIX CO.outlet.T; CO.outlet.T := 40 {K} + 273.15 {K};
238	FIX TU.inlet.p; TU.inlet.p := 150 {bar};
239
240	SOLVER QRSlv;
241	OPTION convopt 'RELNOM_SCALE';
242	END on_load;
243	METHOD set_x_limit;
244	FREE PU.outlet.p;
245	PU.outlet.p.upper_bound := 150 {bar};
246	FIX TU.outlet.x; TU.outlet.x := 0.9;
247	END set_x_limit;
248
249	END combinedcycle_water;
250
251	MODEL combinedcycle_water_opt REFINES combinedcycle_water;
252	MAXIMIZE eta;
253	METHODS
254	METHOD on_load;
255	RUN combinedcycle_water::on_load;
256	braytonpressureratio.lower_bound := 8;
257	braytonpressureratio.upper_bound := 20;
258	END on_load;
259	END combinedcycle_water_opt;
260
261
262
263	MODEL combinedcycle_ammonia REFINES combinedcycle_fprops_common;
264	TU.inlet.cd.component :== 'ammonia';
265	HE.outlet.T = PU.outlet.T + 15 {K};
266	HE.outlet_cold.T = GT.outlet.T - 12 {K};
267	METHODS
268	METHOD default_self;
269	RUN combinedcycle_fprops_common::default_self;
270	(* starting guess, for easy solving *)
271	HE.outlet_cold.h := 400 {kJ/kg};
272	CO.outlet.h := 400 {kJ/kg};
273	END default_self;
274	METHOD on_load;
275	RUN ClearAll;
276	RUN default_self;
277	RUN combinedcycle_fprops_common::specify;
278	FIX Wdot; Wdot := 100 {MW};
279
280	(* ambient conditions *)
281	FIX GC.inlet.T, GC.inlet.p;
282	GC.inlet.T := 30 {K} + 273.15 {K};
283	GC.inlet.p := 1 {bar};
284
285	(* Brayton parameters *)
286	FIX braytonpressureratio; braytonpressureratio := 11.2; (* optimise this *)
287	FIX BU.outlet.T; BU.outlet.T := 970 {K} + 273.15 {K};
288
289	(* Rankine cycle condenser *)
290	CO.outlet.p := 8 {kPa};
291	FIX CO.outlet.T; CO.outlet.T := 40 {K} + 273.15 {K};
292	FIX TU.inlet.p; TU.inlet.p := 150 {bar};
293
294	SOLVER QRSlv;
295	OPTION convopt 'RELNOM_SCALE';
296	END on_load;
297	END combinedcycle_ammonia;
298
299	(*
300	the combinedcycle_co2 model is removed, because it wasn't viable due to the
301	location of the CO2 critical point.
302	*)