CN104696029A - Organic Rankine cycle system and method for switching operation modes thereof - Google Patents

Organic Rankine cycle system and method for switching operation modes thereof Download PDF

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CN104696029A
CN104696029A CN201310722415.5A CN201310722415A CN104696029A CN 104696029 A CN104696029 A CN 104696029A CN 201310722415 A CN201310722415 A CN 201310722415A CN 104696029 A CN104696029 A CN 104696029A
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organic rankine
rankine cycle
cycle system
actual
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CN104696029B (en
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徐菘蔚
郭启荣
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Industrial Technology Research Institute ITRI
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Abstract

An organic Rankine cycle system and a method for switching an operation mode thereof. The switching method comprises the step of judging whether an actual pressure value of a working fluid of the organic Rankine cycle system before entering the inlet of the expander is larger than or equal to a critical pressure value of the working fluid. If yes, the organic Rankine cycle system is operated in a transcritical operation mode. If not, the organic Rankine cycle system is operated in the primary critical operation mode.

Description

The switching method of organic rankine cycle system and operation mode thereof
Technical field
The present invention about a kind of organic rankine cycle system, particularly a kind of organic rankine cycle system and subcritical operation mode thereof and wear the switching method of critical operation pattern.
Background technique
When organic Rankine bottoming cycle (Organic Rankine Cycle, ORC) is used in normal pressure, lower boiling organic substance is working fluid, is most effective in low temperature heat energy generation technology at present and most economical material benefit.Under organic Rankine bottoming cycle operates in transition point according to inner loop working fluid or on divide into subcritical cycle (Sub-critical cycle) system or wear critical cycle (Transcritical cycle) system.Generally speaking, wear critical cycle system and have higher system thermal efficiency and thermal source heat-obtaining rate, therefore under identical cold & heat source condition, its generated energy is larger.
Be applied to wear critical organic rankine cycle system thermal source variation and have a wide reach, comprise the variation type thermals source such as middle low-temperature waste heat, underground heat, hot spring, solar thermal energy.But; because the above-mentioned temperature of variation type thermal source and the supply in the unit time have periodicity, variation that is intermittent or irregularly property; if therefore wear critical organic Rankine bottoming cycle in the face of above-mentioned variation type thermal source time; then likely because the condition variation of thermal source causes organic rankine cycle system to be shut down outward to the condition of wearing the running of critical organic Rankine bottoming cycle, and then the utilization rate of limitation organic rankine cycle system.Thus, the accumulated generation amount of organic rankine cycle system will be reduced, therefore, how promote the generated energy of organic rankine cycle system when variation type thermal source, and then to promote its economic benefit will be one of research staff's problem that should solve.
Summary of the invention
The invention reside in the switching method a kind of organic rankine cycle system and subcritical operation mode thereof being provided and wearing critical operation pattern, so as to promote organic rankine cycle system in the face of variation type thermal source time can operating range.
For achieving the above object, the invention provides a kind of switching method of operation mode of organic rankine cycle system, comprise the following step: judge a working fluid of an organic rankine cycle system enter an expander inlet before an actual pressure value whether be more than or equal to a critical pressure value of working fluid: if so, then make organic rankine cycle system wear critical operation mode operation with one.If not, then make organic rankine cycle system with a critical operation mode operation.
The switching method of the operation mode of above-mentioned organic rankine cycle system, wherein this operating process of wearing critical operation pattern comprises the following step: search a supercritical working fluid pressure and temp database, to obtain the operating temperature range corresponding to this actual pressure value; And judge that this working fluid enters the relation of the actual temperature value before this expander inlet and this operating temperature range: if this actual temperature value is lower than the lower limit of this operating temperature range, then downgrade an output frequency value or an output stream value of the pump driving this working fluid; If this actual temperature value falls within this operating temperature range, then maintain this output frequency value or this output stream value of this pump; And if this actual temperature value is higher than the CLV ceiling limit value of this operating temperature range, then increase this output frequency value or this output stream value of this pump.
The switching method of the operation mode of above-mentioned organic rankine cycle system, if wherein in the lower limit of this actual temperature value lower than this operating temperature range, after then downgrading this output frequency value of this pump or the step of this output stream value, if when also comprising this actual pressure value before entering this expander inlet lower than this critical pressure value, then the operation mode of this organic rankine cycle system is made to be worn critical operation pattern switched to this subcritical operation mode by this.
The switching method of the operation mode of above-mentioned organic rankine cycle system, wherein this wears in the operating process of critical operation pattern, if in the CLV ceiling limit value of this actual temperature value higher than this operating temperature range, after then increasing this output frequency value of this pump or the step of this output stream value, if also comprise this actual pressure value before entering this expander inlet higher than this organic rankine cycle system allow maximum pressure value time, then make this organic rankine cycle system shut down.
The switching method of the operation mode of above-mentioned organic rankine cycle system, wherein this wears in the operating process of critical operation pattern, this supercritical working fluid pressure and temp database has many group pressure and operating temperature range data, and each group pressure has a force value and corresponding operating temperature range with operating temperature range data.
The switching method of the operation mode of above-mentioned organic rankine cycle system, wherein the operating process of this subcritical operation mode comprises the following step: the actual super heat value calculating this working fluid according to this actual pressure value and this actual temperature value; And judge this working fluid enter this expander inlet before this actual super heat value and preset the relation of degree of superheat scope: if this actual super heat value is less than the lower limit of this default degree of superheat scope, then downgrade this output frequency value or this output stream value of this pump; If this actual super heat value falls within the scope of this default degree of superheat, then maintain this output frequency value driving this pump or this output stream value; And if this actual super heat value is greater than the CLV ceiling limit value of this default degree of superheat scope, then increase this output frequency value or this output stream value of this pump.
The switching method of the operation mode of above-mentioned organic rankine cycle system, in the operating process of wherein this subcritical operation mode, if be less than the lower limit of this default degree of superheat scope in this actual super heat value, after then downgrading this output frequency value of this pump or the step of this output stream value, if also comprise this actual pressure value before entering this expander inlet lower than this organic rankine cycle system allow minimum pressure values time, then make this organic rankine cycle system shut down.
The switching method of the operation mode of above-mentioned organic rankine cycle system, if be wherein greater than the CLV ceiling limit value of this default degree of superheat scope in this actual super heat value, after then increasing this output frequency value of this pump or the step of this output stream value, if when also comprising this actual pressure value before entering this expander inlet higher than this critical pressure value, then make the operation mode of this organic rankine cycle system switch to this by this subcritical operation mode and wear critical operation pattern.
The switching method of the operation mode of above-mentioned organic rankine cycle system, wherein this pump is variable delivery pump or flow setting type pump collocation inverter motor.
The switching method of the operation mode of above-mentioned organic rankine cycle system, wherein this decompressor is turbo machine, spiral decompressor, scroll heat exchange system, positive-displacement expansion engine or reciprocating expansion engine.
The switching method of the operation mode of above-mentioned organic rankine cycle system, wherein for should a thermal source of organic rankine cycle system or the temperature of a low-temperature receiver or flow variation time, if this organic rankine cycle system is under this wears critical operation pattern, then perform judge this working fluid enter this expander inlet before an actual temperature value whether fall within step in an operating temperature range, if this organic rankine cycle system is under this subcritical operation mode, then perform judge this working fluid enter this expander inlet before an actual super heat value whether fall within step within the scope of a default degree of superheat.
For achieving the above object, the invention provides a kind of organic rankine cycle system, comprising a heat exchanger of heat source, a decompressor, a condenser, a pump, a pressure sensor and a control unit.Decompressor is connected with heat exchanger of heat source by pipeline.Condenser is connected with decompressor by pipeline.Pump is connected with heat exchanger of heat source with condenser by pipeline.Pump forms an organic Rankine bottoming cycle in order to drive a working fluid sequentially to flow through heat exchanger of heat source, decompressor and condenser by pump.Working fluid has a critical pressure value.Pressure sensor is in order to the actual pressure value of testing fluid at expander inlet.Control unit is in order to judge the relation between the actual pressure value of working fluid and critical pressure value.If the actual pressure value of working fluid is greater than critical pressure value, then control unit controls organic Rankine bottoming cycle and wears critical operation mode operation with one.If the actual pressure value of working fluid is less than critical pressure value, then control unit controls organic Rankine bottoming cycle with a critical operation mode operation.
Above-mentioned organic rankine cycle system, wherein also comprise a temperature-sensitive sticker, the actual temperature value before expander inlet is entered in order to detect this working fluid, a supercritical working fluid pressure and temp database is had in this control unit, this supercritical working fluid pressure and temp database has many group pressure and operating temperature range data, each group pressure has a force value and a corresponding operating temperature range with operating temperature range data, this organic rankine cycle system is when this is worn under critical operation pattern, if this actual temperature value is greater than the CLV ceiling limit value of this operating temperature range, then this control unit improves an output frequency value or an output stream value of this pump, if actual temperature value is less than the lower limit of this operating temperature range, then this control unit reduces this output frequency value or this output stream value of this pump.
Above-mentioned organic rankine cycle system, wherein under this wears critical operation pattern, if what this actual pressure value was greater than this organic rankine cycle system allows maximum pressure value, then this control unit makes this organic rankine cycle system shut down, if this actual pressure value is less than this critical pressure value, then this control unit makes this organic rankine cycle system be worn critical operation pattern switched to this subcritical operation mode by this.
Above-mentioned organic rankine cycle system, wherein there is a degree of superheat in this control unit and calculates module, this degree of superheat of this control unit calculates module calculates this working fluid actual super heat value according to this actual pressure value and this actual temperature value, when this organic Rankine bottoming cycle is under this subcritical operation mode, if this actual super heat value is less than the lower limit that presets degree of superheat scope, then downgrade this output frequency value or this output stream value of this pump, if this actual super heat value is greater than the CLV ceiling limit value that presets degree of superheat scope, then heighten this output frequency value or this output stream value of this pump.
Above-mentioned organic rankine cycle system, wherein under this subcritical operation mode, if what this actual pressure value was less than this organic rankine cycle system allows minimum pressure values, then this control unit makes this organic rankine cycle system shut down, if this actual pressure value is greater than this critical pressure value, then this control unit makes this organic rankine cycle system switch to this by this subcritical operation mode and wears critical operation pattern.
Above-mentioned organic rankine cycle system, wherein this working fluid is an organic refrigerant, and this organic refrigerant is for being selected from one of them of the group that is made up of HFCs, mixing refrigerant, HCs, FCs.
Above-mentioned organic rankine cycle system, wherein this pump is variable delivery pump or flow setting type pump collocation inverter motor.
Above-mentioned organic rankine cycle system, wherein this decompressor is turbo machine, spiral decompressor, scroll heat exchange system, positive-displacement expansion engine or reciprocating expansion engine.
Above-mentioned organic rankine cycle system, wherein also comprises a generator, is connected with this decompressor, the rotation function of this decompressor is converted to electric energy and exports.
Organic rankine cycle system disclosed by the invention described above and subcritical operation mode thereof and wear the switching method of critical operation pattern, the operation mode of organic rankine cycle system is switched by pressure condition, when making the condition variation of working fluid, organic rankine cycle system can continue to be adjusted to suitable operation mode, can operating range and utilization rate and increase its accumulated generation amount in the hope of what can promote organic rankine cycle system, and then promote the economic benefit of organic rankine cycle system.
Above about the explanation of content of the present invention and the explanation of following mode of execution in order to demonstration with explain principle of the present invention, and provide patent claim of the present invention further to explain.
Accompanying drawing explanation
Fig. 1 is the system schematic of organic rankine cycle system according to an embodiment of the invention;
Fig. 2 is the temperature of organic rankine cycle system under the wearing critical operation pattern-entropy performance schematic diagram of Fig. 1;
Fig. 3 is the temperature of organic rankine cycle system under the subcritical operation mode-entropy performance schematic diagram of Fig. 1;
Fig. 4 is the subcritical operation mode of the organic rankine cycle system of Fig. 1 and wears the flow chart of switching method of critical operation pattern;
Fig. 5 is that the organic rankine cycle system of Fig. 1 is in the operational flowchart wearing critical operation pattern;
Fig. 6 and Fig. 7 is the temperature-entropy performance schematic diagram of the heat source temperature variation of the supply organic rankine cycle system of Fig. 1;
Fig. 8 is that the organic rankine cycle system of Fig. 1 is in the operational flowchart of subcritical operation mode.
Wherein, reference character:
Embodiment
Please refer to Fig. 1 to Fig. 3.Fig. 1 is the system schematic of organic rankine cycle system according to an embodiment of the invention.Fig. 2 is the temperature of organic rankine cycle system under the wearing critical operation pattern-entropy performance schematic diagram of Fig. 1.Fig. 3 is the temperature of organic rankine cycle system under the subcritical operation mode-entropy performance schematic diagram of Fig. 1.
As shown in Figure 1, the subcritical organic rankine cycle system 10 with wearing threshold state that operates in of the present embodiment comprises heat exchanger of heat source 100, decompressor 200, condenser 300, pump 400, pressure sensor 510, temperature-sensitive sticker 520, generator 600 and a control unit 700.
Heat exchanger of heat source 100 flows into for an external heat source.Thermal source and organic rankine cycle system 10 carry out heat exchange, to provide organic rankine cycle system 10 heat energy.Thermal source is such as middle low-temperature waste heat, underground heat, hot spring, solar thermal energy etc.Decompressor 200 is in order to releasing fluid pressure.Condenser 300 flows into for an extraneous low-temperature receiver, and low-temperature receiver and organic rankine cycle system 10 carry out heat exchange, are taken away by the heat energy of organic rankine cycle system 10.Low-temperature receiver is such as water-cooled cooling tower, flow through cooler, river, seawater or other cryogens.Pump 400 in order to drive the working-fluid flow of organic rankine cycle system 10, and in order to adjust working fluid pressure.
Be connected with each other by pipeline between heat exchanger of heat source 100, decompressor 200, condenser 300 and pump 400, and pump 400 forms an organic Rankine bottoming cycle, so that thermal power transfer is become mechanical energy in order to drive a working fluid sequentially to flow through heat exchanger of heat source 100, decompressor 200 and condenser 300 by pump 400.Working fluid has a critical pressure value PC (as shown in Figure 2 and Figure 3).If actual pressure value working fluid enters decompressor 200 entrance after flowing through heat exchanger of heat source 100 before is greater than critical pressure value PC, then represents working fluid and only have single-phase at single time point.If working fluid enters the actual pressure value before decompressor 200 entrance lower than critical pressure value PC after flowing through heat exchanger of heat source 100, then represent working fluid, at single time point, there is more than two-phase.Working fluid is an organic refrigerant.The present embodiment is for the organic refrigerant of R-134a, but not as limit, organic refrigerant also can for being selected from by HFCs(as R134a, R245fa, R32, R23, R41, R125, R152a, R236fa etc.), mixing refrigerant (as: R404A, R407C, R507A, R410A etc.), HCs (as: R116, R218, RC318, n-pentane etc.), FCs(is as butane, isobutene, propane, methane etc.) one of them of group that form.In addition, pump 400 is variable delivery pump or flow setting type pump collocation inverter motor.Decompressor 200 is turbo machine, spiral decompressor 200, scroll heat exchange system 200, positive-displacement expansion engine 200 or reciprocating expansion engine 200 etc.
In the present embodiment, pump 400 is flow setting type pump.Control unit 700 changes output frequency value or the output stream value of pump 400 by a converter plant 800.So the inessential element of this converter plant 800, selects the embodiment of variable delivery pump, then without the need to arranging this converter plant 800 at pump 400.
Pressure sensor 510 to flow through after heat exchanger of heat source 100 and the actual pressure value P entered before decompressor 200 entrance in order to testing fluid r.
Temperature-sensitive sticker 520 to flow through after heat exchanger of heat source 100 and the actual temperature value T entered before decompressor 200 entrance in order to testing fluid r.
Generator 600 is connected with decompressor 200.Decompressor 200 converts mechanical energy to electric energy in order to drive generator 600 to operate.
Control unit 700, in order to judge the actual pressure value P of working fluid rwith critical pressure value P cbetween relation, if the actual pressure value P of working fluid rbe greater than critical pressure value P c, then control unit 700 controls organic rankine cycle system 10 and wears critical operation mode operation (temperature-entropy performance schematic diagram wearing the organic rankine cycle system 10 under critical operation pattern is as shown in Figure 2) with one.If the actual pressure value P of working fluid rbe less than critical pressure value P c, then control unit 700 controls organic rankine cycle system 10 with a critical operation mode operation (temperature-entropy performance schematic diagram of the organic rankine cycle system 10 under subcritical operation mode is as shown in Figure 3).
Organic rankine cycle system 10 is when installing, can first decide the operating temperature range of organic rankine cycle system 10 when wearing critical operation mode operation corresponding to each force value according to the operating parameters of thermal source historical data and temperature/flow variation situation and organic rankine cycle system 10 and preset applicable degree of superheat scope when subcritical operation mode running, and above-mentioned information is embedded in a supercritical working fluid pressure and temp database and the degree of superheat calculating module of control unit 700, can calculate by supercritical working fluid pressure and temp database and the degree of superheat output frequency value or the output stream value that module carrys out automatic-adjusting pump 400 to make control unit 700.
Supercritical working fluid pressure and temp database has organic rankine cycle system 10 in the lower many groups pressure of subcritical operation mode running and operating temperature range data, and each is organized pressure and has a force value and corresponding operating temperature range with operating temperature range data.
Refer to Fig. 4 to Fig. 5.Fig. 4 is the subcritical operation mode of the organic rankine cycle system of Fig. 1 and wears the flow chart of switching method of critical operation pattern.Fig. 5 is that the organic rankine cycle system of Fig. 1 is in the operational flowchart wearing critical operation pattern.
As shown in Figure 4.First, control unit 700 can judge that the working fluid of organic rankine cycle system 10 is by entering the actual pressure value P before decompressor 200 entrance after heat exchanger of heat source 100 rwhether be more than or equal to a critical pressure value PC (as indicated in step sloo) of working fluid.
If so, then control unit 700 can make organic rankine cycle system 10 wear critical operation mode operation (as shown in step S200) with one.
If not, then control unit 700 can make organic rankine cycle system 10 with a critical operation mode operation (as shown in step S300).
As shown in Figure 5, wear the operator scheme of critical operation pattern, first, control unit 700 can search a supercritical working fluid pressure and temp database, to obtain actual pressure value P ra corresponding operating temperature range (as shown in step S210).
Then, control unit 700 can judge that working fluid is by entering the actual temperature value T before decompressor 200 entrance after heat exchanger of heat source 100 rwith operating temperature range T rrelation (as shown in step S220).
If temperature-sensitive sticker 520 records the actual temperature value T of the working fluid before entering decompressor 200 entrance rlower than the lower limit T of operating temperature range r, MIN, then control unit 700 can downgrade output frequency value or the output stream value (as shown in step S230) of pump 400.If pressure sensor 510 records the actual pressure value P of the working fluid before decompressor 200 entrance rduring lower than critical pressure value PC, then control unit 700 can make the operation mode of organic rankine cycle system 10 switch to subcritical operation mode (as shown in step S260) by wearing critical operation pattern, improves accumulated generation amount to make organic rankine cycle system 10 can continue generating.
If temperature-sensitive sticker 520 records the actual temperature value T of the working fluid before entering decompressor 200 entrance rfall within operating temperature range, then maintain output frequency value or the output stream value (as shown in step S240) of the pump 400 driving working fluid.
If temperature-sensitive sticker 520 records the actual temperature value T of the working fluid before entering decompressor 200 entrance rhigher than the CLV ceiling limit value T of operating temperature range r, MAX, then control unit 700 can increase output frequency value or the output stream value (as shown in step S250) of pump 400.If pressure sensor 510 records the actual pressure value P of the working fluid before entering decompressor 200 entrance rmaximum pressure value P is allowed higher than organic rankine cycle system 10 a, MAXtime, then control unit 700 can make organic rankine cycle system 10 shut down (as shown in step S270), damages to avoid organic rankine cycle system 10.
Below illustrate the operating conditions of organic rankine cycle system 10 under wearing critical conduction mode.Refer to Fig. 6 and Fig. 7.Fig. 6 and Fig. 7 is the temperature-entropy performance schematic diagram of the heat source temperature variation of the supply organic rankine cycle system of Fig. 1.
Suppose to stablize thermal source (temperature Ts1, flow Ms1) with under low-temperature receiver condition one, organic rankine cycle system 10 is wearing steady running under critical operation pattern.Working fluid is before entering decompressor 200, and the pressure of working fluid, temperature and mass flowrate are respectively the first pressure value P 1, first temperature value T1 and the first mass flowrate M1 (being directly proportional to the output frequency value of pump 400 or output stream value).When low-temperature receiver fix, thermal source flow fix but temperature raise time, the first temperature value T1 of the working fluid after heat exchange can be increased to the first transient-state temperature value T1-1.Now, control unit 700 can be walked unhurriedly the output frequency value or output stream value that increase pump 400, and then the pressure of working fluid is increased to the second pressure value P 2 (mass flowrate of working fluid also corresponding can be increased to the second mass flowrate M2 from the first mass flowrate M2) by the first pressure value P 1.Because working fluid mass flow rate increases (M2>M1), and external heat source is limited, drops to the second temperature value T2 by making the temperature of the working fluid before entering decompressor 200 entrance by the first transient-state temperature value T1-1.Now, control unit 700 can judge whether this second temperature value T2 falls within the operating temperature range of this second pressure value P 2, if do not meet, continue output frequency value or the output stream value of modulation pump 400, until the temperature value of working fluid falls within operating temperature range.In addition, suppose that the second pressure value P 2 of the working fluid after adjusting allows maximum operating pressure value P higher than system a, MAX, then control unit 700 can make organic rankine cycle system 10 shut down.
Suppose to stablize thermal source (temperature Ts1, flow Ms1) with under low-temperature receiver condition one, organic rankine cycle system 10 is wearing steady running under critical operation pattern.Working fluid is before entering decompressor 200, and the pressure of working fluid, temperature and mass flowrate are respectively the first pressure value P 1, first temperature value T1 and the first mass flowrate M1 (being directly proportional to the output frequency value of pump 400 or output stream value).When low-temperature receiver fix, thermal source flow fix but temperature reduce time, the first temperature value T1 of the working fluid after heat exchange can be reduced to the second transient-state temperature value T1-2.Now, control unit 700 can be walked unhurriedly the output frequency value or output stream value that downgrade pump 400, and then the pressure of working fluid is reduced to the 3rd pressure value P 3 (mass flowrate of working fluid also corresponding can be reduced to the 3rd mass flowrate M3 from the first mass flowrate M2) by the first pressure value P 1.Because working fluid mass flow rate reduces (M3<M1), and external heat source is limited, rises to the 3rd temperature value T3 by making the temperature of the working fluid before entering decompressor 200 entrance by the second transient-state temperature value T1-2.Now, control unit 700 can judge whether this second temperature value T2 falls within the operating temperature range of this second pressure value P 2, if do not meet, continue output frequency value or the output stream value of modulation pump 400, until the temperature value of working fluid falls within operating temperature range.In addition, suppose the critical pressure value PC of the 3rd pressure value P 3 lower than working fluid of the working fluid after adjusting, then control unit 700 can make the operation mode of organic rankine cycle system 10 switch to subcritical operation mode by wearing critical operation pattern.Suppose that the 3rd pressure value P 3 of the working fluid after adjusting allows minimum operating pressure value P lower than system a, MIN, then control unit 700 can make organic rankine cycle system 10 shut down.
In addition, if when heat source temperature is fixed and changes flow variation into, then the programmed sequence of operations of organic rankine cycle system 10 is also same as described above, therefore repeats no more.
Above-mentioned, the output frequency value of control unit 700 modulation pump 400 or the method for output stream value control setting by PID.
Refer to Fig. 8.Fig. 8 is that the organic rankine cycle system of Fig. 1 is in the operational flowchart of subcritical operation mode.
As shown in Figure 8, the operator scheme of subcritical operation mode, first, the degree of superheat of control unit 700 calculates module and can enter the actual pressure value P before decompressor 200 entrance according to working fluid rand actual temperature value T r, calculate an actual super heat value OS r(as shown in step S310).
Then, control unit 700 can judge the actual super heat value OS of the working fluid before entering decompressor 200 entrance rdegree of superheat scope OS is preset with one rrelation (as shown in step S320).
If temperature-sensitive sticker 520 records the actual super heat value OS of the working fluid before entering decompressor 200 entrance rbe less than the lower limit OS of default degree of superheat scope r, MIN, then control unit 700 can downgrade output frequency value or the output stream value (as shown in step S330) of pump 400.If pressure sensor 510 records the actual pressure value P before entering decompressor 200 entrance rminimum pressure values P is allowed lower than organic rankine cycle system 10 a, MINtime, then control unit 700 can make organic rankine cycle system 10 shut down (as shown in step S360), damages to avoid organic rankine cycle system 10.
If temperature-sensitive sticker 520 records the actual temperature value T of the working fluid before entering decompressor 200 entrance rfall within operating temperature range T rin, then maintain an output frequency value or the output stream value (as shown in step S340) of the pump 400 driving working fluid.
If if temperature-sensitive sticker 520 records the actual super heat value OS of the working fluid before entering decompressor 200 entrance rbe greater than the CLV ceiling limit value OS of default degree of superheat scope r, MAX, then control unit 700 can increase output frequency value or the output stream value (as shown in step S350) of pump 400.If pressure sensor 510 records the actual pressure value P of the working fluid before entering decompressor 200 entrance rhigher than critical pressure value P ctime, then control unit 700 can make the operation mode of organic rankine cycle system 10 be switched to by subcritical operation mode and wear critical operation pattern (as shown in step S370), in the hope of obtaining preferably generating efficiency.
Organic rankine cycle system disclosed by the invention described above and subcritical operation mode thereof and wear the switching method of critical operation pattern, except passing through pressure condition, the operation mode of organic rankine cycle system is also switched by operating temperature range condition and degree of superheat condition, when making the condition variation of extraneous cold & heat source, organic rankine cycle system can continue to be adjusted to suitable operation mode, can operating range and utilization rate and increase its accumulated generation amount in the hope of what can promote organic rankine cycle system, and then promote the economic benefit of organic rankine cycle system.

Claims (20)

1. a switching method for the operation mode of organic rankine cycle system, is characterized in that, comprises the following step:
Judge a working fluid of an organic rankine cycle system enter an expander inlet before an actual pressure value whether be more than or equal to a critical pressure value of this working fluid:
If so, this organic rankine cycle system is then made to wear critical operation mode operation with one; And
If not, then make this organic rankine cycle system with a critical operation mode operation.
2. the switching method of the operation mode of organic rankine cycle system as claimed in claim 1, it is characterized in that, this operating process of wearing critical operation pattern comprises the following step:
Search a supercritical working fluid pressure and temp database, to obtain the operating temperature range corresponding to this actual pressure value; And
Judge that this working fluid enters the relation of the actual temperature value before this expander inlet and this operating temperature range:
If this actual temperature value is lower than the lower limit of this operating temperature range, then downgrade an output frequency value or an output stream value of the pump driving this working fluid;
If this actual temperature value falls within this operating temperature range, then maintain this output frequency value or this output stream value of this pump; And
If this actual temperature value is higher than the CLV ceiling limit value of this operating temperature range, then increase this output frequency value or this output stream value of this pump.
3. the switching method of the operation mode of organic rankine cycle system as claimed in claim 2, it is characterized in that, if in the lower limit of this actual temperature value lower than this operating temperature range, after then downgrading this output frequency value of this pump or the step of this output stream value, if when also comprising this actual pressure value before entering this expander inlet lower than this critical pressure value, then the operation mode of this organic rankine cycle system is made to be worn critical operation pattern switched to this subcritical operation mode by this.
4. the switching method of the operation mode of organic rankine cycle system as claimed in claim 2, it is characterized in that, this wears in the operating process of critical operation pattern, if in the CLV ceiling limit value of this actual temperature value higher than this operating temperature range, after then increasing this output frequency value of this pump or the step of this output stream value, if also comprise this actual pressure value before entering this expander inlet higher than this organic rankine cycle system allow maximum pressure value time, then make this organic rankine cycle system shut down.
5. the switching method of the operation mode of organic rankine cycle system as claimed in claim 2, it is characterized in that, this wears in the operating process of critical operation pattern, this supercritical working fluid pressure and temp database has many group pressure and operating temperature range data, and each group pressure has a force value and corresponding operating temperature range with operating temperature range data.
6. the switching method of the operation mode of organic rankine cycle system as claimed in claim 1, it is characterized in that, the operating process of this subcritical operation mode comprises the following step:
An actual super heat value of this working fluid is calculated according to this actual pressure value and this actual temperature value; And
Judge that this working fluid enters the relation that this actual super heat value before this expander inlet and presets degree of superheat scope:
If this actual super heat value is less than the lower limit of this default degree of superheat scope, then downgrade this output frequency value or this output stream value of this pump;
If this actual super heat value falls within the scope of this default degree of superheat, then maintain this output frequency value driving this pump or this output stream value; And
If this actual super heat value is greater than the CLV ceiling limit value of this default degree of superheat scope, then increase this output frequency value or this output stream value of this pump.
7. the switching method of the operation mode of organic rankine cycle system as claimed in claim 6, it is characterized in that, in the operating process of wherein this subcritical operation mode, if be less than the lower limit of this default degree of superheat scope in this actual super heat value, after then downgrading this output frequency value of this pump or the step of this output stream value, if also comprise this actual pressure value before entering this expander inlet lower than this organic rankine cycle system allow minimum pressure values time, then make this organic rankine cycle system shut down.
8. the switching method of the operation mode of organic rankine cycle system as claimed in claim 6, it is characterized in that, if be greater than the CLV ceiling limit value of this default degree of superheat scope in this actual super heat value, after then increasing this output frequency value of this pump or the step of this output stream value, if when also comprising this actual pressure value before entering this expander inlet higher than this critical pressure value, then make the operation mode of this organic rankine cycle system switch to this by this subcritical operation mode and wear critical operation pattern.
9. the switching method of the operation mode of organic rankine cycle system as claimed in claim 1, is characterized in that, this pump is variable delivery pump or flow setting type pump collocation inverter motor.
10. the switching method of the operation mode of organic rankine cycle system as claimed in claim 1, it is characterized in that, this decompressor is turbo machine, spiral decompressor, scroll heat exchange system, positive-displacement expansion engine or reciprocating expansion engine.
The switching method of the operation mode of 11. organic rankine cycle systems as claimed in claim 1, it is characterized in that, for should a thermal source of organic rankine cycle system or the temperature of a low-temperature receiver or flow variation time, if this organic rankine cycle system is under this wears critical operation pattern, then perform judge this working fluid enter this expander inlet before an actual temperature value whether fall within step in an operating temperature range, if this organic rankine cycle system is under this subcritical operation mode, then perform judge this working fluid enter this expander inlet before an actual super heat value whether fall within step within the scope of a default degree of superheat.
12. 1 kinds of organic rankine cycle systems, is characterized in that, comprise:
One heat exchanger of heat source;
One decompressor, is connected with this heat exchanger of heat source by pipeline;
One condenser, is connected with this decompressor by pipeline;
One pump, be connected with this heat exchanger of heat source with this condenser by pipeline, this pump forms an organic Rankine bottoming cycle in order to drive a working fluid sequentially to flow through this heat exchanger of heat source, this decompressor and this condenser by this pump, and this working fluid has a critical pressure value;
One pressure sensor, enters the actual pressure value before expander inlet in order to detect this working fluid; And
One control unit, in order to judge the relation between this actual pressure value of this working fluid and this critical pressure value, if this actual pressure value of this working fluid is greater than this critical pressure value, then this control unit controls this organic rankine cycle system and wears critical operation mode operation with one, if this actual pressure value of this working fluid is less than this critical pressure value, then this control unit controls this organic rankine cycle system with a critical operation mode operation.
13. organic rankine cycle systems as claimed in claim 12, it is characterized in that, also comprise a temperature-sensitive sticker, the actual temperature value before expander inlet is entered in order to detect this working fluid, a supercritical working fluid pressure and temp database is had in this control unit, this supercritical working fluid pressure and temp database has many group pressure and operating temperature range data, each group pressure has a force value and a corresponding operating temperature range with operating temperature range data, this organic rankine cycle system is when this is worn under critical operation pattern, if this actual temperature value is greater than the CLV ceiling limit value of this operating temperature range, then this control unit improves an output frequency value or an output stream value of this pump, if actual temperature value is less than the lower limit of this operating temperature range, then this control unit reduces this output frequency value or this output stream value of this pump.
14. organic rankine cycle systems as claimed in claim 13, it is characterized in that, under this wears critical operation pattern, if what this actual pressure value was greater than this organic rankine cycle system allows maximum pressure value, then this control unit makes this organic rankine cycle system shut down, if this actual pressure value is less than this critical pressure value, then this control unit makes this organic rankine cycle system be worn critical operation pattern switched to this subcritical operation mode by this.
15. organic rankine cycle systems as claimed in claim 13, it is characterized in that, there is a degree of superheat in this control unit and calculates module, this degree of superheat of this control unit calculates module calculates this working fluid actual super heat value according to this actual pressure value and this actual temperature value, when this organic Rankine bottoming cycle is under this subcritical operation mode, if this actual super heat value is less than the lower limit that presets degree of superheat scope, then downgrade this output frequency value or this output stream value of this pump, if this actual super heat value is greater than the CLV ceiling limit value that presets degree of superheat scope, then heighten this output frequency value or this output stream value of this pump.
16. organic rankine cycle systems as claimed in claim 15, it is characterized in that, under this subcritical operation mode, if what this actual pressure value was less than this organic rankine cycle system allows minimum pressure values, then this control unit makes this organic rankine cycle system shut down, if this actual pressure value is greater than this critical pressure value, then this control unit makes this organic rankine cycle system switch to this by this subcritical operation mode and wears critical operation pattern.
17. organic rankine cycle systems as claimed in claim 12, is characterized in that, this working fluid is an organic refrigerant, and this organic refrigerant is for being selected from one of them of the group that is made up of HFCs, mixing refrigerant, HCs, FCs.
18. organic rankine cycle systems as claimed in claim 12, is characterized in that, this pump is variable delivery pump or flow setting type pump collocation inverter motor.
19. organic rankine cycle systems as claimed in claim 12, is characterized in that, this decompressor is turbo machine, spiral decompressor, scroll heat exchange system, positive-displacement expansion engine or reciprocating expansion engine.
20. organic rankine cycle systems as claimed in claim 12, is characterized in that, also comprise a generator, be connected with this decompressor, the rotation function of this decompressor are converted to electric energy and export.
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