SINGLE-WORKING-MEDIUM VAPOR COMBINED CYCLE

The single-working-medium vapor combined cycle is provided in this invitation and belongs to the field of energy and power technology. A single-working-medium vapor combined cycle consists of nine processes which are conducted with M1 kg of working medium and M2 kg of working medium separately or jointly: a pressurization process 1-2 of the M1 kg of working medium, a heat-absorption vaporization and superheating process 2-3 of the M1 kg of working medium, a depressurization process 3-4 of the M1 kg of working medium, a pressurization process 7-4 of M2 kg of working medium, a heat-absorption process 4-5 of the M3 kg of working medium, a depressurization process 5-6 of the M3 kg of working medium, a heat-releasing process 6-7 of the M3 kg of working medium, a heat-releasing and condensation process 7-1 of the M1 kg of working medium; M3 is the sum of M1 and M2.

FIELD

The present invention belongs to the field of energy and power technology.

Cold demand, heat demand and power demand are common in human life and production. It is an important way to obtain and provide power by the conversion of thermal energy into mechanical energy. In general, the temperature of heat source reduces and varies with the release of heat. When fossil fuels are used as the primary energy, the heat source has the dual characteristics of both high temperature and variable temperature. Therefore, only one single thermodynamic cycle cannot achieve an ideal efficiency for refrigeration, heating or power generation.

Take the vapor power device with external combustion for example, its heat source has the dual characteristics of high temperature and variable temperature. For those vapor power devices based on the Rankine cycle, the material's temperature resistance and pressure resistance abilities and safety concerns limit the parameters of the cycle's working medium. Therefore, there is a big temperature difference between the working medium and the heat source, which leads to big irreversible loss and low efficiency.

Humans need new basic theory of thermal science to use fuel or other high temperature thermal energy simply, actively, efficiently for achieving refrigeration, heating or power. In the basic theory system of thermal science, thermodynamic cycles are the theoretical basis of thermal energy utilization devices, and the core of energy utilization systems. The establishment, development and application of thermodynamic cycles will play an important role in the rapid development of energy utilization and will promote actively for social progress and productivity development.

Based on the principles of simple, active and efficient utilization of temperature difference, aiming at the power generation application of high temperature heat sources or variable temperature heat sources, and striving to provide theoretical support for the simplification and high efficiency of thermo-power systems, the present invention proposes a single-working-medium vapor combined cycle.

THE CONTENTS OF THE PRESENT INVENTION

The single working-medium vapor combined cycle and the vapor power device for combined cycle are mainly provided in the present invention, and the specific content of the present invention is as follows:

1. A single-working-medium vapor combined cycle method consisting of twelve processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption and vaporization process to set the state (2) to (3) of the M1kg of working medium, performing a depressurization process to set the state (3) to (4) of the M1kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the M1kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (8) of the H kg of working medium, performing a pressurization process to set a state (8) to (5) of the M2kg of working medium, performing a heat-absorption process to set a state (5) to (6) of the (M1+M2) kg of working medium, performing a depressurization process to set the state (6) to (7) of the (M1+M2) kg of working medium, performing a mixed heat-releasing process to set the state (7) to (8) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (8) to (9) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (9) to (1) of the (M1+H) kg of working medium.

2. A single-working-medium vapor combined cycle method consisting of thirteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption and vaporization process to set the state (2) to (3) of the M1kg of working medium, performing a depressurization process to set the state (3) to (4) of the M1kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the M1kg of working medium, performing a depressurization process to set the state (5) to (7) of the M1kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (9) of the H kg of working medium, performing a pressurization process to set a state (9) to (6) of the M2kg of working medium, performing a heat-absorption process to set the state (6) to (7) of the M2kg of working medium, performing a depressurization process to set a state (7) to (8) of the (M1+M2) kg of working medium, performing a mixed heat-releasing process to set the state (8) to (9) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (9) to (c) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (c) to (1) of the (M1+H) kg of working medium.

3. A single-working-medium vapor combined cycle method consisting of thirteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption and vaporization process to set the state (2) to (3) of the M1kg of working medium, performing a depressurization process to set the state (3) to (4) of the M1kg of working medium, performing a heat-absorption process to set the state (4) to (7) of the M1kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (9) of the H kg of working medium, performing a pressurization process to set a state (9) to (5) of the M2kg of working medium, performing a heat-absorption process to set the state (5) to (6) of the M2kg of working medium, performing a depressurization process to set the state (6) to (7) of the M2kg of working medium, performing a depressurization process to set a state (7) to (8) of the (M1+M2) kg of working medium, performing a mixed heat-releasing process to set the state (8) to (9) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (9) to (c) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (c) to (1) of the (M1+H) kg of working medium.

4. A single-working-medium vapor combined cycle method consisting of fourteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption and vaporization process to set the state (2) to (3) of the M1kg of working medium, performing a depressurization process to set the state (3) to (4) of the M1kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the M1kg of working medium, performing a depressurization process to set the state (5) to (9) of the M1kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (c) of the H kg of working medium, performing a pressurization process to set a state (c) to (6) of the M2kg of working medium, performing a heat-absorption process to set the state (6) to (7) of the M2kg of working medium, performing a depressurization process to set the state (7) to (8) of the M2kg of working medium, performing a mixed heat-releasing process to set a state (8) to (9) of the M2kg of working medium and the H kg of working medium, performing a mixed heat-releasing process to set a state (9) to (c) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (c) to (d) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (d) to (1) of the (M1+H) kg of working medium.

5. A single-working-medium vapor combined cycle method consisting of fourteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption and vaporization process to set the state (2) to (3) of the M1kg of working medium, performing a depressurization process to set the state (3) to (4) of the M1kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the M1kg of working medium, performing a depressurization process to set the state (5) to (6) of the M1kg of working medium, performing a mixed heat-releasing process to set a state (6) to (9) of the M1kg of working medium and the H kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (c) of the H kg of working medium, performing a pressurization process to set a state (c) to (7) of the M2kg of working medium, performing a heat-absorption process to set the state (7) to (8) of the M2kg of working medium, performing a depressurization process to set the state (8) to (9) of the M2kg of working medium, performing a mixed heat-releasing process to set a state (9) to (c) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (c) to (d) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (d) to (1) of the (M1+H) kg of working medium.

6. A single-working-medium vapor combined cycle method consisting of fifteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption and vaporization process to set the state (2) to (3) of the M1kg of working medium, performing a depressurization process to set the state (3) to (4) of the M1kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the M1kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (c) of the H kg of working medium, performing a pressurization process to set a state (c) to (5) of the M2kg of working medium, performing a heat-absorption process to set a state (5) to (6) of the (M1+M2) kg of working medium, performing a depressurization process to set a state (6) to (9) of the X kg of working medium, performing a heat-absorption process to set a state (6) to (7) of the (M1+M2−X) kg of working medium, performing a depressurization process to set the state (7) to (8) of the (M1+M2−X) kg of working medium, performing a mixed heat-releasing process to set a state (8) to (9) of the (M1+M2−X) kg of working medium and the H kg of working medium, performing a mixed heat-releasing process to set a state (9) to (c) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (c) to (d) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (d) to (1) of the (M1+H) kg of working medium.

7. A single-working-medium vapor combined cycle method consisting of fifteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption process to set the state (2) to (b) of the M1kg of working medium, performing a heat-absorption and vaporization process to set a state (b) to (3) of the (M1+M) kg of working medium, performing a depressurization process to set the state (3) to (4) of the (M1+M) kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the (M1+M) kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (8) of the H kg of working medium, performing a pressurization process to set a state (8) to (a) of the M2kg of working medium, performing a heat-releasing and condensation process to set a state (a) to (b) of the M kg of working medium, performing a pressurization process to set a state (a) to (5) of the (M2−M) kg of working medium, performing a heat-absorption process to set a state (5) to (6) of the (M1+M2) kg of working medium, performing a depressurization process to set the state (6) to (7) of the (M1+M2) kg of working medium, performing a mixed heat-releasing process to set a state (7) to (8) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (8) to (9) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (9) to (1) of the (M1+H) kg of working medium.

8. A single-working-medium vapor combined cycle method consisting of sixteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption process to set the state (2) to (b) of the M1kg of working medium, performing a heat-absorption and vaporization process to set a state (b) to (3) of the (M1+M) kg of working medium, performing a depressurization process to set the state (3) to (4) of the (M1+M) kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the (M1+M) kg of working medium, performing a depressurization process to set the state (5) to (7) of the (M1+M) kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (9) of the H kg of working medium, performing a pressurization process to set a state (9) to (a) of the M2kg of working medium, performing a heat-releasing and condensation process to set a state (a) to (b) of the M kg of working medium, performing a pressurization process to set a state (a) to (6) of the (M2−M) kg of working medium, performing a heat-absorption process to set the state (6) to (7) of the (M2−M) kg of working medium, performing a depressurization process to set a state (7) to (8) of the (M1+M2) kg of working medium, performing a mixed heat-releasing process to set a state (8) to (9) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (9) to (c) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (c) to (1) of the (M1+H) kg of working medium.

9. A single-working-medium vapor combined cycle method consisting of sixteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption process to set the state (2) to (b) of the M1kg of working medium, performing a heat-absorption and vaporization process to set a state (b) to (3) of the (M1+M) kg of working medium, performing a depressurization process to set the state (3) to (4) of the (M1+M) kg of working medium, performing a heat-absorption process to set the state (4) to (7) of the (M1+M) kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (9) of the H kg of working medium, performing a pressurization process to set a state (9) to (a) of the M2kg of working medium, performing a heat-releasing and condensation process to set a state (a) to (b) of the M kg of working medium, performing a pressurization process to set a state (a) to (5) of the (M2−M) kg of working medium, performing a heat-absorption process to set the state (5) to (6) of the (M2−M) kg of working medium, performing a depressurization process to set a state (6) to (7) of the (M2−M) kg of working medium, performing a depressurization process to set the state (7) to (8) of the (M1+M2) kg of working medium, performing a mixed heat-releasing process to set a state (8) to (9) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (9) to (c) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (c) to (1) of the (M1+H) kg of working medium.

10. A single-working-medium vapor combined cycle method consisting of seventeen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption process to set the state (2) to (b) of the M1kg of working medium, performing a heat-absorption and vaporization process to set a state (b) to (3) of the (M1+M) kg of working medium, performing a depressurization process to set the state (3) to (4) of the (M1+M) kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the (M1+M) kg of working medium, performing a depressurization process to set the state (5) to (9) of the (M1+M) kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (c) of the H kg of working medium, performing a pressurization process to set a state (c) to (a) of the M2kg of working medium, performing a heat-releasing and condensation process to set a state (a) to (b) of the M kg of working medium, performing a pressurization process to set a state (a) to (6) of the (M2−M) kg of working medium, performing a heat-absorption process to set the state (6) to (7) of the (M2−M) kg of working medium, performing a depressurization process to set a state (7) to (8) of the (M2−M) kg of working medium, performing a mixed heat-releasing process to set a state (8) to (9) of the (M2−M) kg of working medium and the H kg of working medium, performing a mixed heat-releasing process to set a state (9) to (c) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (c) to (d) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (d) to (1) of the (M1+H) kg of working medium.

11. A single-working-medium vapor combined cycle method consisting of seventeen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption process to set the state (2) to (b) of the M1kg of working medium, performing a heat-absorption and vaporization process to set a state (b) to (3) of the (M1+M) kg of working medium, performing a depressurization process to set the state (3) to (4) of the (M1+M) kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the (M1+M) kg of working medium, performing a depressurization process to set the state (5) to (6) of the (M1+M) kg of working medium, performing a mixed heat-releasing process to set a state (6) to (9) of the (M1+M) kg of working medium and the H kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (c) of the H kg of working medium, performing a pressurization process to set a state (c) to (a) of the M2kg of working medium, performing a heat-releasing and condensation process to set a state (a) to (b) of the M kg of working medium, performing a pressurization process to set a state (a) to (7) of the (M2−M) kg of working medium, performing a heat-absorption process to set the state (7) to (8) of the (M2−M) kg of working medium, performing a depressurization process to set a state (8) to (9) of the (M2−M) kg of working medium, performing a mixed heat-releasing process to set a state (9) to (c) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (c) to (d) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (d) to (1) of the (M1+H) kg of working medium.

12. A single-working-medium vapor combined cycle method consisting of eighteen processes which are conducted with M1kg of working medium, M2kg of working medium and H kg of working medium separately or jointly: performing a pressurization process to set a state (1) to (2) of the M1kg of working medium, performing a heat-absorption process to set the state (2) to (b) of the M1kg of working medium, performing a heat-absorption and vaporization process to set a state (b) to (3) of the (M1+M) kg of working medium, performing a depressurization process to set the state (3) to (4) of the (M1+M) kg of working medium, performing a heat-absorption process to set the state (4) to (5) of the (M1+M) kg of working medium, performing a pressurization process to set a state (1) to (e) of the H kg of working medium, performing a heat-absorption process to set the state (e) to (c) of the H kg of working medium, performing a pressurization process to set a state (c) to (a) of the M2kg of working medium, performing a heat-releasing and condensation process to set a state (a) to (b) of the M kg of working medium, performing a pressurization process to set a state (a) to (5) of the (M2−M) kg of working medium, performing a heat-absorption process to set a state (5) to (6) of the (M1+M2) kg of working medium, performing a depressurization process to set a state (6) to (9) of the X kg of working medium, performing a heat-absorption process to set the state (6) to (7) of the (M1+M2−X) kg of working medium, performing a depressurization process to set the state (7) to (8) of the (M1+M2−X) kg of working medium, performing a mixed heat-releasing process to set a state (8) to (9) of the (M1+M2−X) kg of working medium and the H kg of working medium, performing a mixed heat-releasing process to set a state (9) to (c) of the (M1+M2) kg of working medium and the H kg of working medium, performing a depressurization process to set a state (c) to (d) of the (M1+H) kg of working medium, performing a heat-releasing and condensation process to set the state (d) to (1) of the (M1+H) kg of working medium.

DETAILED DESCRIPTION

The first thing to note is that, when describing the cycle's structures and processes, the processes will not be repeatedly described if not necessary, and the obvious processes will not be described. The detailed description of the present invention is as follows:

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 1works as follows:

(1) From the Perspective of the Cycle's Processes.

The working medium conducts twelve processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption vaporization and superheating process2-3of the M1kg of working medium, a depressurization process3-4of the M1kg of working medium, a heat-absorption process4-5of the M1kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-8of the H kg of working medium, a pressurization process8-5of the M2kg of working medium, a heat-absorption process5-6of the (M1+M2) kg of working medium, a depressurization process6-7of the (M1+M2) kg of working medium, a mixed heat-releasing process7-8of the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process8-9of the (M1+H) kg of working medium, a heat-releasing and condensation process9-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-8of the H kg of working medium is provided by the heat-releasing in the process7-8of the (M1+M2) kg of working medium, or by an external heat source at the same time. In the process2-3of the M1kg of working medium, the process4-5of the M1kg of working medium and the process5-6of the (M1+M2) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process7-8, the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state8. The heat released by the (M1+H) kg of working medium in process9-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process8-5of the M2kg of working medium is usually achieved by a compressor. The depressurization (and expansion) process3-4of the M1kg of working medium, the depressurization (and expansion) process6-7of the (M1+M2) kg of working medium and the depressurization (and expansion) process8-9of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 2works as follows:

(1) From the Perspective of the Cycle's Processes.

The working medium conducts thirteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption vaporization and superheating process2-3of the M1kg of working medium, a depressurization process3-4of the M1kg of working medium, a heat-absorption process4-5of the M1kg of working medium, a depressurization process5-7of the M1kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-9of the H kg of working medium, a pressurization process9-6of the M2kg of working medium, a heat-absorption process6-7of the M2kg of working medium, a depressurization process7-8of the (M1+M2) kg of working medium, a mixed heat-releasing process8-9of the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process9-cof the (M1+H) kg of working medium, a heat-releasing and condensation process c-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-9of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M1+M2) kg of working medium, or by an external heat source at the same time. In the process2-3of the M1kg of working medium, the process4-5of the M1kg of working medium and the process6-7of the M2kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state 9. The heat released by the (M1+H) kg of working medium in process c-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process9-6of the M2kg of working medium is usually achieved by a compressor. The depressurization (and expansion) process3-4of the M1kg of working medium, the depressurization (and expansion) process5-7of the M1kg of working medium, the depressurization (and expansion) process7-8of the (M1+M2) kg of working medium and the depressurization (and expansion) process9-cof the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 3works as follows:

(1) From the Perspective of the Cycle's Processes.

The working medium conducts thirteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption vaporization and superheating process2-3of the M1kg of working medium, a depressurization process3-4of the M1kg of working medium, a heat-absorption process4-7of the M1kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-9of the H kg of working medium, a pressurization process9-5of the M2kg of working medium, a heat-absorption process5-6of the M2kg of working medium, a depressurization process6-7of the M2kg of working medium, a depressurization process7-8of the (M1+M2) kg of working medium, a mixed heat-releasing process8-9of the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process9-cof the (M1+H) kg of working medium, a heat-releasing and condensation process c-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-9of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M1+M2) kg of working medium, or by an external heat source at the same time. In the process2-3of the M1kg of working medium, the process4-7of the M1kg of working medium and the process5-6of the M2kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state 9. The heat released by the (M1+H) kg of working medium in process c-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process9-5of the M2kg of working medium is usually achieved by a compressor. The depressurization (and expansion) process3-4of the M1kg of working medium, the depressurization (and expansion) process6-7of the M2kg of working medium, the depressurization (and expansion) process7-8of the (M1+M2) kg of working medium and the depressurization (and expansion) process9-cof the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 4works as follows:

(1) From the Perspective of the Cycle's Processes.

The working medium conducts fourteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption vaporization and superheating process2-3of the M1kg of working medium, a depressurization process3-4of the M1kg of working medium, a heat-absorption process4-5of the M1kg of working medium, a depressurization process5-9of the M1kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-c of the H kg of working medium, a pressurization process c-6of the M2kg of working medium, a heat-absorption process6-7of the M2kg of working medium, a depressurization process7-8of the M2kg of working medium, a mixed heat-releasing process8-9of the M2kg of working medium and the H kg of working medium, a mixed heat-releasing process9-cof the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process c-d of the (M1+H) kg of working medium, a heat-releasing and condensation process d-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-c of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M1+M2−X) kg of working medium and the process9-cof the (M1+M2) kg of working medium, or by an external heat source at the same time. In the process2-3of the M1kg of working medium, the process4-5of the M1kg of working medium and the process6-7of the M2kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the M2kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the M2kg of working medium is lowered to state 9. In the process9-c,the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state c. The heat released by the (M1+H) kg of working medium in process d-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process c-6of the M2kg of working medium is usually achieved by a compressor. The depressurization process3-4of the M1kg of working medium, the depressurization process5-9of the M1kg of working medium, the depressurization process7-8of the M2kg of working medium and the depressurization (and expansion) process c-d of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 5works as follows:

(1) From the Perspective of the Cycle's Processes.

The working medium conducts fourteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption vaporization and superheating process2-3of the M1kg of working medium, a depressurization process3-4of the M1kg of working medium, a heat-absorption process4-5of the M1kg of working medium, a depressurization process5-6of the M1kg of working medium, a mixed heat-releasing process6-9of the M1kg of working medium and the H kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-c of the H kg of working medium, a pressurization process c-7of the M2kg of working medium, a heat-absorption process7-8of the M2kg of working medium, a depressurization process8-9of the M2kg of working medium, a mixed heat-releasing process9-cof the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process c-d of the (M1+H) kg of working medium, a heat-releasing and condensation process d-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-c of the H kg of working medium is provided by the heat-releasing in the process6-9of the M1kg of working medium and the process9-cof the (M1+M2) kg of working medium, or by an external heat source at the same time. In the process2-3of the M1kg of working medium, the process4-5of the M1kg of working medium and the process5-6of the M2kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process6-9, the M1kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the M2kg of working medium is lowered to state 9. In the process9-c,the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state c. The heat released by the (M1+H) kg of working medium in process d-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process c-7of the M2kg of working medium is usually achieved by a compressor. The depressurization (and expansion) process3-4of the M1kg of working medium, the depressurization (and expansion) process5-6of the M1kg of working medium, the depressurization (and expansion) process8-9of the M2kg of working medium and the depressurization (and expansion) process c-d of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 6works as follows:

(1) From the Perspective of the Cycle's Processes.

The working medium conducts fifteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption vaporization and superheating process2-3of the M1kg of working medium, a depressurization process3-4of the M1kg of working medium, a heat-absorption process4-5of the M1kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-c of the H kg of working medium, a pressurization process c-5of the M2kg of working medium, a heat-absorption process5-6of the (M1+M2) kg of working medium, a depressurization process6-9of the X kg of working medium, a heat-absorption process6-7of the (M1+M2−X) kg of working medium, a depressurization process7-8of the (M1+M2−X) kg of working medium, a mixed heat-releasing process8-9of the (M1+M2−X) kg of working medium and the H kg of working medium, a mixed heat-releasing process9-cof the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process c-d of the (M1+H) kg of working medium, a heat-releasing and condensation process d-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-c of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M1+M2−X) kg of working medium and the process9-cof the (M1+M2) kg of working medium, or by an external heat source at the same time. In the process2-3of the M1kg of working medium, the process4-5of the M1kg of working medium, the process5-6of the (M1+M2) kg of working medium and the process6-7of the (M1+M2−X) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the (M1+M2−X) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2−X) kg of working medium is lowered to state 9. In the process9-c,the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state c. The heat released by the (M1+H) kg of working medium in process d-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process c-5of the M2kg of working medium is usually achieved by a compressor. The depressurization (and expansion) process3-4of the M1kg of working medium, the depressurization (and expansion) process6-9of the X kg of working medium, the depressurization (and expansion) process7-8of the (M1+M2−X) kg of working medium and the depressurization (and expansion) process c-d of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 7works as follows:

(1) From the Perspective of the Cycle's Processes.

The working medium conducts twelve processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption process2-bof the M1kg of working medium, a heat-absorption vaporization and superheating process b-3of the (M1+M) kg of working medium, a depressurization process3-4of the (M1+M) kg of working medium, a heat-absorption process4-5of the (M1+M) kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-8of the H kg of working medium, a pressurization process8-aof the M2kg of working medium, a mixed heat-releasing process a-b of the M kg of working medium and the M1kg of working medium, a pressurization process a-5of the (M2−M) kg of working medium, a heat-absorption process5-6of the (M1+M2) kg of working medium, a depressurization process6-7of the (M1+M2) kg of working medium, a mixed heat-releasing process7-8of the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process8-9of the (M1+H) kg of working medium, a heat-releasing and condensation process9-1of the (M1+H) kg of working medium.

(2) From the perspective of energy conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-8of the H kg of working medium is provided by the heat-releasing in the process7-8of the (M1+M2) kg of working medium, or by an external heat source at the same time. The absorbed heat in the process2-bof the M1kg of working medium is provided by the mixed heat-releasing of the M kg of working medium, or by an external heat source at the same time. In the process b-3of the (M1+M) kg of working medium, the process4-5of the (M1+M) kg of working medium and the process5-6of the (M1+M2) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process7-8, the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state 8. The heat released by the (M1+H) kg of working medium in process9-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process8-aof the M2kg of working medium and the pressurization process a-5of the (M2−M) kg of working medium are usually achieved by compressors. The depressurization (and expansion) process3-4of the (M1+M) kg of working medium, the depressurization (and expansion) process6-7of the (M1+M) kg of working medium and the depressurization (and expansion) process8-9of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 8works as follows:

(1) From the perspective of the cycle's processes. The working medium conducts sixteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption process2-bof the M1kg of working medium, a heat-absorption vaporization and superheating process b-3of the (M1+M) kg of working medium, a depressurization process3-4of the (M1+M) kg of working medium, a heat-absorption process4-5of the (M1+M) kg of working medium, a depressurization process5-7of the (M1+M) kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-9of the H kg of working medium, a pressurization process9-aof the M2kg of working medium, a mixed heat-releasing process a-b of the M kg of working medium and the M1kg of working medium, a pressurization process a-6of the (M2−M) kg of working medium, a heat-absorption process6-7of the (M2−M) kg of working medium, a depressurization process7-8of the (M1+M2) kg of working medium, a mixed heat-releasing process8-9of the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process9-cof the (M1+H) kg of working medium, a heat-releasing and condensation process c-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-9of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M1+M2) kg of working medium, or by an external heat source at the same time. The absorbed heat in the process2-bof the M1kg of working medium is provided by the mixed heat-releasing of the M kg of working medium, or by an external heat source at the same time. In the process b-3of the (M1+M) kg of working medium, the process4-5of the (M1+M) kg of working medium and the process6-7of the (M2−M) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state 9. The heat released by the (M1+H) kg of working medium in process c-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process9-aof the M2kg of working medium and the pressurization process a-6of the (M2−M) kg of working medium are usually achieved by compressors. The depressurization (and expansion) process3-4of the (M1+M) kg of working medium, the depressurization (and expansion) process5-7of the (M1+M) kg of working medium, the depressurization (and expansion) process7-8of the (M1+M2) kg of working medium and the depressurization (and expansion) process9-cof the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 9works as follows:

(1) From the perspective of the cycle's processes. The working medium conducts sixteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption process2-bof the M1kg of working medium, a heat-absorption vaporization and superheating process b-3of the (M1+M) kg of working medium, a depressurization process3-4of the (M1+M) kg of working medium, a heat-absorption process4-7of the (M1+M) kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-9of the H kg of working medium, a pressurization process9-aof the M2kg of working medium, a mixed heat-releasing process a-b of the M kg of working medium and the M1kg of working medium, a pressurization process a-5of the (M2−M) kg of working medium, a heat-absorption process5-6of the (M2−M) kg of working medium, a depressurization process6-7of the (M2−M) kg of working medium, a depressurization process7-8of the (M1+M2) kg of working medium, a mixed heat-releasing process8-9of the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process9-cof the (M1+H) kg of working medium, a heat-releasing and condensation process c-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-9of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M1+M2) kg of working medium, or by an external heat source at the same time. The absorbed heat in the process2-bof the M1kg of working medium is provided by the mixed heat-releasing of the M kg of working medium, or by an external heat source at the same time. In the process b-3of the (M1+M) kg of working medium, the process4-7of the (M1+M) kg of working medium and the process5-6of the (M2−M) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state 9. The heat released by the (M1+H) kg of working medium in process c-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process9-aof the M2kg of working medium and the pressurization process a-5of the (M2−M) kg of working medium are usually achieved by compressors. The depressurization (and expansion) process3-4of the (M1+M) kg of working medium, the depressurization (and expansion) process6-7of the (M2−M) kg of working medium, the depressurization (and expansion) process7-8of the (M1+M2) kg of working medium and the depressurization (and expansion) process9-cof the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 10works as follows:

(1) From the perspective of the cycle's processes. The working medium conducts seventeen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption process2-bof the M1kg of working medium, a heat-absorption vaporization and superheating process b-3of the (M1+M) kg of working medium, a depressurization process3-4of the (M1+M) kg of working medium, a heat-absorption process4-5of the (M1+M) kg of working medium, a depressurization process5-9of the (M1+M) kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-c of the H kg of working medium, a pressurization process c-a of the M2kg of working medium, a mixed heat-releasing process a-b of the M kg of working medium and the M1kg of working medium, a pressurization process a-6of the (M2−M) kg of working medium, a heat-absorption process6-7of the (M2−M) kg of working medium, a depressurization process7-8of the (M2−M) kg of working medium, a mixed heat-releasing process8-9of the (M2−M) kg of working medium and the H kg of working medium, a mixed heat-releasing process9-cof the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process c-d of the (M1+H) kg of working medium, a heat-releasing and condensation process d-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-c of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M2−M) kg of working medium and the process9-cof the (M1+M2) kg of working medium, or by an external heat source at the same time. The absorbed heat in the process2-bof the M1kg of working medium is provided by the mixed heat-releasing of the M kg of working medium, or by an external heat source at the same time. In the process b-3of the (M1+M) kg of working medium, the process4-5of the (M1+M) kg of working medium and the process6-7of the (M2−M) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the (M2−M) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M2−M) kg of working medium is lowered to state 9. In the process9-c,the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state c. The heat released by the (M1+H) kg of working medium in process d-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process c-a of the M2kg of working medium and the pressurization process a-6of the (M2−M) kg of working medium are usually achieved by compressors. The depressurization (and expansion) process3-4of the (M1+M) kg of working medium, the depressurization (and expansion) process5-9of the (M1+M) kg of working medium, the depressurization (and expansion) process7-8of the (M2−M) kg of working medium and the depressurization (and expansion) process c-d of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 11works as follows:

(1) From the perspective of the cycle's processes. The working medium conducts seventeen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption process2-bof the M1kg of working medium, a heat-absorption vaporization and superheating process b-3of the (M1+M) kg of working medium, a depressurization process3-4of the (M1+M) kg of working medium, a heat-absorption process4-5of the (M1+M) kg of working medium, a depressurization process5-6of the (M1+M) kg of working medium, a mixed heat-releasing process6-9of the (M1+M) kg of working medium and the H kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-c of the H kg of working medium, a pressurization process c-a of the M2kg of working medium, a mixed heat-releasing process a-b of the M kg of working medium and the M1kg of working medium, a pressurization process a-7of the (M2−M) kg of working medium, a heat-absorption process7-8of the (M2−M) kg of working medium, a depressurization process8-9of the (M2−M) kg of working medium, a mixed heat-releasing process9-cof the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process c-d of the (M1+H) kg of working medium, a heat-releasing and condensation process d-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-c of the H kg of working medium is provided by the heat-releasing in the process6-9of the (M1+M) kg of working medium and the process9-cof the (M1+M2) kg of working medium, or by an external heat source at the same time. The absorbed heat in the process2-bof the M1kg of working medium is provided by the mixed heat-releasing of the M kg of working medium, or by an external heat source at the same time. In the process b-3of the (M1+M) kg of working medium, the process4-5of the (M1+M) kg of working medium and the process7-8of the (M2−M) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process6-9, the (M1+M) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M2−M) kg of working medium is lowered to state 9. In the process9-c,the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state c. The heat released by the (M1+H) kg of working medium in process d-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process c-a of the M2kg of working medium and the pressurization process a-7of the (M2−M) kg of working medium are usually achieved by compressors. The depressurization (and expansion) process3-4of the (M1+M) kg of working medium, the depressurization (and expansion) process5-6of the (M1+M) kg of working medium, the depressurization (and expansion) process8-9of the (M2−M) kg of working medium and the depressurization (and expansion) process c-d of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The T-s diagram of the single-working-medium vapor combined cycle inFIG. 12works as follows:

(1) From the perspective of the cycle's processes. The working medium conducts eighteen processes: a pressurization process1-2of the M1kg of working medium, a heat-absorption process2-bof the M1kg of working medium, a heat-absorption vaporization and superheating process b-3of the (M1+M) kg of working medium, a depressurization process3-4of the (M1+M) kg of working medium, a heat-absorption process4-5of the (M1+M) kg of working medium, a pressurization process1-eof the H kg of working medium, a heat-absorption vaporization and superheating process e-c of the H kg of working medium, a pressurization process c-a of the M2kg of working medium, a mixed heat-releasing process a-b of the M kg of working medium and the M1kg of working medium, a pressurization process a-5of the (M2−M) kg of working medium, a heat-absorption process5-6of the (M1+M2) kg of working medium, a depressurization process6-9of the X kg of working medium, a heat-absorption process6-7of the (M1+M2−X) kg of working medium, a depressurization process7-8of the (M1+M2−X) kg of working medium, a mixed heat-releasing process8-9of the (M1+M2−X) kg of working medium and the H kg of working medium, a mixed heat-releasing process9-cof the (M1+M2) kg of working medium and the H kg of working medium, a depressurization process c-d of the (M1+H) kg of working medium, a heat-releasing and condensation process d-1of the (M1+H) kg of working medium.

(2) From the Perspective of Energy Conversion.

{circle around (1)} Heat absorption processes: the absorbed heat in the process e-c of the H kg of working medium is provided by the heat-releasing in the process8-9of the (M1+M2−X) kg of working medium and the process9-cof the (M1+M2) kg of working medium, or by an external heat source at the same time. The absorbed heat in the process2-bof the M1kg of working medium is provided by the mixed heat-releasing of the M kg of working medium, or by an external heat source at the same time. In the process b-3of the (M1+M) kg of working medium, the process4-5of the (M1+M) kg of working medium, the process5-6of the (M1+M2) kg of working medium and the process6-7of the (M1+M2−X) kg of working medium, the absorbed heat is provided by an external heat source.

{circle around (2)} Heat-releasing processes. In the process8-9, the (M1+M2−X) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M2−M) kg of working medium is lowered to state 9. In the process9-c,the (M1+M2) kg of working medium mixes with and releases heat to the H kg of working medium, and the temperature of the (M1+M2) kg of working medium is lowered to state c. The heat released by the (M1+H) kg of working medium in process d-1is usually released to the low-temperature heat sink, or be supplied to the heat user when cogeneration is applicable.

{circle around (3)} Energy conversion processes. The pressurization process1-2of the M1kg of working medium and the pressurization process1-eof H kg of working medium are usually achieved by pumps. The pressurization process c-a of the M2kg of working medium and the pressurization process a-5of the (M2−M) kg of working medium are usually achieved by compressors. The depressurization (and expansion) process3-4of the (M1+M) kg of working medium, the depressurization (and expansion) process6-9of the X kg of working medium, the depressurization (and expansion) process7-8of the (M1+M2−X) kg of working medium and the depressurization (and expansion) process c-d of the (M1+H) kg of working medium are usually achieved by expanders. The total expansion work output is greater than the total pressurization work input; therefore, thermal energy is converted into power (the cycle's net work), and the single-working-medium vapor combined cycle is completed.

The technical effects of the present invention invention: The single-working-medium vapor combined cycle proposed by the present invention has the following effects and advantages:

(1) A basic theory of thermal energy (temperature difference) utilization has been created.

(2) The present invention greatly reduces the amount of heat absorbed in the phase-change region, and correspondingly increases the amount of heat absorbed in the high-temperature region or the variable temperature region. Therefore, the single-working-medium vapor combined cycle can achieve high efficiency.

(3) The present invention possesses simple methods, reasonable processes and good applicability. It is a common technology to realize the effective utilization of temperature differences.

(4) The present invention only uses a single working medium, which is easy to produce and store. The present invention can also reduce the operation cost and improve the flexibility of cycle regulation.

(5) The processes in the present invention are shared and reduced, which provides a theoretical basis for reducing equipment investment.

(6) In the high temperature region or the variable temperature region, both the cycle's working medium and the heat source medium conduct variable-temperature processes; therefore, the temperature difference loss is reduced and the efficiency is improved.

(7) The present invention adopts the low-pressure and high-temperature operation mode in the high-temperature region; therefore, the contradiction among thermal efficiency, the working medium's parameters and the material's temperature resistance and pressure resistance abilities, which is common in traditional vapor power devices, can be resolved.

(8) Under the precondition of achieving a high thermal efficiency, the vapor power device provided in the present invention can operate at a low pressure. The present invention provides theoretical support for improving the safety of device operation.

(9) The present invention possesses a wide range of applicable working media. The present invention can match energy supply with demand well. It is flexible to match the working medium and the working parameters.

(10) The present invention expands the range of thermodynamic cycles for temperature difference utilization, and contributes to a higher-efficiency power generation of high-temperature heat sources and variable-temperature heat sources.