CN111288678A - Single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulation system - Google Patents
Single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulation system Download PDFInfo
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- CN111288678A CN111288678A CN202010158603.XA CN202010158603A CN111288678A CN 111288678 A CN111288678 A CN 111288678A CN 202010158603 A CN202010158603 A CN 202010158603A CN 111288678 A CN111288678 A CN 111288678A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B13/00—Compression machines, plants or systems, with reversible cycle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/40—Fluid line arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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- Engineering & Computer Science (AREA)
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- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Compression-Type Refrigeration Machines With Reversible Cycles (AREA)
Abstract
The invention discloses a single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulating system which comprises a first compressor, a second compressor, a condensation heat exchanger, a first throttling valve, an evaporation subcooler, a second throttling valve, an evaporation heat exchanger and a four-way valve, wherein the first throttling valve is connected with the first compressor; according to the invention, the four-way valve can be used for realizing the switching of the parallel single-stage compression and the serial two-stage compression of the first compressor and the second compressor according to the operation condition; the new evaporation supercooling mode can reduce the gasification amount and throttling loss of the throttled working medium, and improve the COP of the system while increasing the refrigerating and heating capacities of the system; the problems that when the supercooling technologies such as a heat regenerator, air supply and enthalpy increase are implemented, the obtained supercooling degree is limited, the supercooling degree is limited by the middle replenishing pressure, the compression type is limited and the like are solved.
Description
Technical Field
The invention relates to the technical field of energy consumption for building air conditioning and heating, in particular to a single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulating system.
Background
For the vapor compression type circulation, the supercooling degree of the condenser is increased, so that the refrigerating capacity of unit refrigerant flowing through the evaporator can be increased, and the COP of the system can be improved. The existing supercooling mode mainly adopts two modes of a regenerator and an economizer. Although both the regenerator and the economizer can achieve subcooling, the two are clearly different. For the regenerator, the degree of subcooling of the refrigerant before the throttle is increased while the degree of superheat at the compressor suction is also increased, with subcooling being beneficial for the system COP but superheat being detrimental thereto. For a quasi-two-stage compression system using an economizer, only a vapor-supplementing enthalpy-increasing turbocompressor can be used, and meanwhile, the refrigeration capacity of part of refrigerant is sacrificed and is limited by the intermediate vapor-supplementing pressure. When the vapor-supplementing enthalpy-increasing technology is implemented, the supercooling degree is limited by the middle supplementing pressure. For a single stage compression system using an economizer, the cycle has limited capability to increase system COP when achieving large subcooling, since the economizer and evaporator pressures are the same.
1. Heat regenerator
The regenerator is also called a gas-liquid heat exchanger. A heat exchange apparatus for subcooling and superheating a refrigerant liquid in a refrigeration system utilizes refrigerant vapor from an evaporator to cool the high pressure liquid prior to entering the evaporator.
The method is characterized in that: the gas entering the compressor can become superheated steam by using the heat regenerator, so that liquid drops carried in the return gas are gasified, and the compressor is prevented from generating liquid impact; the liquid entering the evaporator is supercooled, and throttling loss is reduced. The degree of subcooling of the refrigerant before the throttle is increased while the degree of superheat at the compressor suction is also increased, with subcooling being beneficial for the system COP but superheat being detrimental thereto.
2. Quasi-two-stage compression system adopting economizer
The gas-supplementing enthalpy-increasing scroll compressor is a compressor with a gas-supplementing structure, changes a one-way gas suction mode into a one-way gas suction mode and a one-way gas supplementing mode, and is also called a quasi-two-stage compressor. The air supply channel is provided with an air supply hole in the middle of the vortex disc, and gas, liquid or gas-liquid mixture is sprayed to the compression cavity, so that the exhaust temperature is reduced, and the performance of the air supply channel under extreme working conditions is improved.
The method is characterized in that: the gas-supplementing enthalpy-increasing scroll compressor reduces the enthalpy value of the rest part of refrigerant by sacrificing a part of refrigerant, thereby improving the energy efficiency, and supplementing the sacrificed gas in the compression process to achieve the effect of reducing the exhaust temperature. Therefore, the performance can be better under the extreme working condition. But at the same time, the refrigeration capacity of part of the refrigerant is sacrificed, and the quasi-two-stage compression of the form can only use a turbo compressor and is limited by the intermediate air supply pressure. When the vapor-supplying enthalpy-increasing technology is implemented, a part of problems need to be solved, such as control strategies, matching of vapor-supplying throttling elements, consideration of economy and the like.
3. Single stage compression system using economizer
A single-stage compression system of an economizer is adopted, and a one-path throttling evaporation mode is changed into a mode that one-path refrigerant working medium is evaporated in the economizer and is used for supercooling the other-path refrigerant working medium. The circulation mode can obtain larger supercooling degree, but the supercooling degree of the system COP is limited, and the circulation mode cannot adjust the optimal supercooling degree to enable the system COP to reach the maximum value and cannot adjust the supercooling degree to improve the heating/refrigerating capacity of the refrigerating system.
Disclosure of Invention
The invention aims to provide a single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulating system aiming at the defects in the prior art,
in order to solve the technical problems, the invention adopts the following technical scheme:
a single-stage and double-stage switching evaporation and supercooling refrigeration heat pump circulating system comprises a first compressor, a second compressor, a condensation heat exchanger, a first throttling valve, an evaporation subcooler, a second throttling valve, an evaporation heat exchanger and a four-way valve;
the exhaust port of the first compressor is connected with the inlet end of the condensing heat exchanger through a first pipeline; an exhaust port of the second compressor is connected with a first port of the four-way valve through a second pipeline; the third pipeline is respectively connected with the first pipeline and a fourth port of the four-way valve; the outlet end of the condensing heat exchanger is connected with the high-temperature side inlet of the evaporation subcooler through a fourth pipeline, the high-temperature side outlet of the evaporation subcooler is connected with one end of the evaporation heat exchanger through a sixth pipeline, a second throttling valve is arranged on the sixth pipeline, and the other end of the evaporation heat exchanger is connected with the suction inlet of a second compressor through an eighth pipeline; the fifth pipeline is respectively connected with the fourth pipeline and an evaporation side inlet of the evaporation subcooler, a first throttle valve is arranged on the fifth pipeline, and an evaporation side outlet of the evaporation subcooler is connected with a suction inlet of the first compressor through a seventh pipeline; the ninth pipeline is respectively connected with the seventh pipeline and a third port of the four-way valve, and a one-way valve is arranged on the ninth pipeline, so that the third port of the four-way valve can only enter but not exit; the tenth pipeline is respectively connected with the seventh pipeline and the second port of the four-way valve.
Compared with the prior art, the invention has the following beneficial effects:
1. the method avoids the phenomenon that the super-cooling degree of the refrigerant before the throttling valve is increased by using a heat regenerator, and simultaneously, the superheat degree of a suction inlet of a compressor is also increased, wherein the super-cooling is beneficial to the system COP, but the superheat is harmful to the system COP.
2. The problems that the air-supplementing enthalpy-increasing turbo compressor adopting an economizer sacrifices the refrigerating capacity of part of refrigerant, the quasi-two-stage compression only can use the turbo compressor and is limited by the middle air-supplementing pressure are solved; the problem that the COP improvement capacity of the system is limited when large supercooling degree is obtained by adopting a single-stage compression system of the economizer is solved.
3. The supercooling circulation mode provided by the invention is beneficial to improving the actual operation performance of the system and can reduce the irreversible loss of the system.
4. The temperature drop in the evaporation subcooler in the circulation system of the invention has an optimal value (i.e. corresponds to an optimal supercooling degree). The contradiction between the heat supply of the heat pump and the heat demand of the building when the air source heat pump runs in winter can be solved by adjusting the temperature drop in the evaporation subcooler.
5. The circulating system can realize single-stage and double-stage switching to deal with outdoor temperature change, thereby ensuring the requirements of cooling capacity, heating capacity and heating temperature and solving the heat supply and demand contradiction of air source heat pump heating.
Drawings
Fig. 1 is a schematic diagram of the structure of the present invention.
Reference numerals: 1-a first compressor; 101-suction of the first compressor; 102-a discharge port of the first compressor; 2-a second compressor; 201-suction of the second compressor; 202-a discharge port of the second compressor; 3-a condensing heat exchanger; 4-a first throttle valve; 5-an evaporation subcooler; 6-a second throttle valve; 7-an evaporative heat exchanger; a 8-four-way valve; 801 — a first port; 802 — a second port; 803-third port; 804-a fourth port; 9-a one-way valve;
l01 — first line; l02 — second line; l03 — third line; l04 — fourth line; l05-fifth line; l06-sixth line; l07-seventh line; l08 — eighth line; l09-ninth line; l10-tenth line.
Detailed Description
The present invention will be described in further detail with reference to examples for the purpose of facilitating understanding and practice of the invention by those of ordinary skill in the art, and it is to be understood that the present invention has been described in the illustrative embodiments and is not to be construed as limited thereto.
A single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulating system comprises: the system comprises a first compressor 1, a second compressor 2, a condensing heat exchanger 3, a first throttling valve 4, an evaporation subcooler 5, a second throttling valve 6, an evaporation heat exchanger 7 and a four-way valve 8.
The discharge outlet 102 of the first compressor 1 is connected to the inlet end of the condensing heat exchanger 3 through a first line L01; the exhaust port 202 of the second compressor 2 is connected to the first port 801 of the four-way valve 8 through a second line L02; the third line L03 is connected to the first line L01 and the fourth port 804 of the four-way valve 8, respectively; the outlet end of the condensing heat exchanger 3 is connected with the high-temperature side inlet of the evaporation subcooler 5 through a fourth pipeline L04, the high-temperature side outlet of the evaporation subcooler 5 is connected with one end of the evaporation heat exchanger 7 through a sixth pipeline L06, a second throttle valve 6 is arranged on the sixth pipeline L06, and the other end of the evaporation heat exchanger 7 is connected with the suction inlet 201 of the second compressor 2 through an eighth pipeline L08; the fifth pipeline L05 is respectively connected to the fourth pipeline L04 and the evaporation side inlet of the evaporation subcooler 5, the fifth pipeline L05 is provided with the first throttle valve 4, and the evaporation side outlet of the evaporation subcooler 5 is connected with the suction port 101 of the first compressor 1 through the seventh pipeline L07; the ninth pipeline L09 is respectively connected to the seventh pipeline L07 and the third port 803 of the four-way valve 8, and the ninth pipeline L09 is provided with a check valve 9, so that the third port 803 of the four-way valve 8 can only enter but not exit; the tenth line L10 connects the seventh line L07 and the second port 802 of the four-way valve 8, respectively.
In the invention, the evaporation subcooler 5 preferably adopts an economizer, and can also adopt the forms of a flash evaporator, a heat exchanger and the like, thereby realizing the subcooling of the working medium entering the throttling valve, and the evaporation pressure of the evaporation subcooler can be adjusted according to the size of the subcooling degree.
In the invention, CO can be used as the recycled working medium2The working medium can also adopt other refrigerant working media, and the cycle is simultaneously suitable for two system cycle modes of transcritical and subcritical.
When the first compressor 1 and the second compressor 2 are in parallel single-stage compression operation:
as shown in fig. 1, when the first compressor 1 and the second compressor 2 are in parallel single-stage compression operation, the first port 801 and the fourth port 804 of the four-way valve 8 are communicated, the second port 802 and the third port 803 are communicated, the high-temperature high-pressure gas discharged from the second compressor 2 enters the first port 801 of the four-way valve 8 through the second pipeline L02, and after being discharged through the fourth port 804 of the four-way valve 8, enters the first pipeline L01 through the third pipeline L03, and then joins with the high-temperature high-pressure gas discharged from the first compressor 1 in the first pipeline L01, and after entering the condensing heat exchanger 3 for heat exchange, the high-temperature high-pressure gas is divided into two paths: one path of working medium enters the evaporation subcooler 5 for evaporation and heat absorption after being throttled by the first throttle valve 4, then returns to the suction inlet of the first compressor 1, and is subcooled in the evaporation subcooler 5 (or the flash tank) for the other path of working medium; the other path of the subcooled working medium enters the evaporating heat exchanger 7 for evaporation and heat absorption after being throttled by the second throttle valve 6, then returns to the suction inlet of the second compressor 2, is compressed by the second compressor 2, enters the first port 801 of the four-way valve 8 through the second pipeline L02, is discharged through the fourth port 804 of the four-way valve 8, enters the first pipeline L01 through the third pipeline L03, and then is converged with the high-temperature and high-pressure gas discharged by the first compressor 1 in the first pipeline L01.
The first compressor 1 and the second compressor 2 are connected in series and operated in a two-stage compression mode:
as shown in fig. 1, when the first compressor 1 and the second compressor 2 are connected in series and operate in a two-stage compression mode, the first port 801 and the second port 802 of the four-way valve 8 are communicated, the third port 803 and the fourth port 804 are communicated, and the high-temperature and high-pressure gas discharged by the first compressor 1 is divided into two paths after heat exchange by the condensing heat exchanger 3: one path of working medium enters an evaporation subcooler 5 (or a flash evaporator) for evaporation and heat absorption after being throttled by a first throttle valve 4, and the other path of working medium is subcooled in the evaporation subcooler 5 (or the flash evaporator); the other path of the subcooled working medium enters an evaporative heat exchanger 7 for evaporation and heat absorption after being throttled by a second throttle valve 6, then returns to a suction inlet of a second compressor 2, is compressed by the second compressor 2, enters a first port 801 of a four-way valve 8 through a second pipeline L02, is discharged through a second port 802 of the four-way valve 8, is sent to a seventh pipeline L07 through a tenth pipeline L10, and then is converged with a medium-pressure working medium coming out of an evaporative subcooler (5) in a seventh pipeline L07; then back to the suction inlet of the first compressor 1 and finally into the first compressor 1.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.
Claims (1)
1. A single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulating system comprises a first compressor (1), and is characterized by further comprising a second compressor (2), a condensation heat exchanger (3), a first throttling valve (4), an evaporation supercooling unit (5), a second throttling valve (6), an evaporation heat exchanger (7) and a four-way valve (8);
the exhaust (102) of the first compressor (1) is connected to the inlet end of the condensing heat exchanger (3) via a first line (L01); an exhaust port (202) of the second compressor (2) is connected with a first port (801) of the four-way valve (8) through a second pipeline (L02); the third pipeline (L03) is respectively connected with the first pipeline (L01) and the fourth port (804) of the four-way valve (8); the outlet end of the condensing heat exchanger (3) is connected with the high-temperature side inlet of the evaporation subcooler (5) through a fourth pipeline (L04), the high-temperature side outlet of the evaporation subcooler (5) is connected with one end of the evaporation heat exchanger (7) through a sixth pipeline (L06), a second throttle valve (6) is arranged on the sixth pipeline (L06), and the other end of the evaporation heat exchanger (7) is connected with the suction inlet (201) of the second compressor (2) through an eighth pipeline (L08); a fifth pipeline (L05) is respectively connected with the fourth pipeline (L04) and an evaporation side inlet of the evaporation subcooler (5), a first throttle valve (4) is arranged on the fifth pipeline (L05), and an evaporation side outlet of the evaporation subcooler (5) is connected with a suction inlet (101) of the first compressor (1) through a seventh pipeline (L07); the ninth pipeline (L09) is respectively connected with the seventh pipeline (L07) and the third port (803) of the four-way valve (8), and the ninth pipeline (L09) is provided with a one-way valve (9), so that the third port (803) of the four-way valve (8) can only enter but not exit; the tenth line (L10) is connected to the seventh line (L07) and the second port (802) of the four-way valve (8), respectively.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010158603.XA CN111288678A (en) | 2020-03-09 | 2020-03-09 | Single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulation system |
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| CN202010158603.XA CN111288678A (en) | 2020-03-09 | 2020-03-09 | Single-stage and double-stage switching evaporation supercooling refrigeration heat pump circulation system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112197452A (en) * | 2020-10-14 | 2021-01-08 | 珠海格力电器股份有限公司 | Refrigeration system with deep freezing function and control method thereof |
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2020
- 2020-03-09 CN CN202010158603.XA patent/CN111288678A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112197452A (en) * | 2020-10-14 | 2021-01-08 | 珠海格力电器股份有限公司 | Refrigeration system with deep freezing function and control method thereof |
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