CN113531935A - Overlapping heat pump circulating system and control method - Google Patents
Overlapping heat pump circulating system and control method Download PDFInfo
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- CN113531935A CN113531935A CN202110639064.6A CN202110639064A CN113531935A CN 113531935 A CN113531935 A CN 113531935A CN 202110639064 A CN202110639064 A CN 202110639064A CN 113531935 A CN113531935 A CN 113531935A
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- 238000000034 method Methods 0.000 title claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 258
- 239000003507 refrigerant Substances 0.000 claims abstract description 158
- 238000010438 heat treatment Methods 0.000 claims description 16
- 238000010257 thawing Methods 0.000 claims description 11
- 238000010586 diagram Methods 0.000 description 8
- 238000002360 preparation method Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000005485 electric heating Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000008236 heating water Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
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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
- F25B7/00—Compression machines, plants or systems, with cascade operation, i.e. with two or more circuits, the heat from the condenser of one circuit being absorbed by the evaporator of the next circuit
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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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Abstract
The invention discloses a cascade heat pump circulation system and a control method, wherein the system comprises a primary refrigerant circulation loop, an evaporative condenser and a primary condenser, wherein the primary refrigerant circulation loop comprises the evaporative condenser and the primary condenser and is used for exchanging heat with water flowing through the primary condenser based on a first refrigerant and/or exchanging heat with a second refrigerant flowing through the evaporative condenser based on the first refrigerant; the secondary refrigerant circulation loop comprises the evaporative condenser and a secondary condenser and is used for absorbing heat transferred by the first refrigerant from the evaporative condenser based on the second refrigerant and transferring heat to water flowing through the secondary condenser based on the second refrigerant; the system also comprises a water circulation loop, the system can prepare medium-temperature water based on the first-stage refrigerant circulation loop, and prepare high-temperature water based on the first-stage refrigerant circulation loop and the second-stage refrigerant circulation loop, so that the efficiency of preparing the high-temperature water is improved, and the energy efficiency of the overlapping heat pump circulation system is improved on the basis of improving the water outlet temperature.
Description
Technical Field
The present application relates to the field of heat pump technology, and more particularly, to a cascade heat pump circulation system and a control method.
Background
The heat pump hot water system is more explosive in the industry in recent two years, the main reason is that the country has seen historical targets of carbon peak reaching and carbon neutralization, and the heat pump hot water system has the use characteristics of high energy efficiency and low energy consumption, and has the great advantages of environmental protection, energy conservation and the like compared with the traditional boiler, electric heating and the like, so the heat pump hot water system has gained wide attention in the industry.
However, the traditional air source heat pump also has some use limitations, for example, the maximum heating temperature can only reach 60 ℃, which can meet most of the requirements of domestic hot water and heating in winter, but for the use scenes of hospitals, foods, hotels and the like with more high-temperature water applications, high-temperature hot water at 80-90 ℃ cannot be directly prepared by the traditional air source heat pump product, and low-energy-efficiency and high-energy-consumption modes such as boilers, gas furnaces, electric heating and the like are still needed. Therefore, the high-water-temperature-output cascade heat pump needs to be used for making up for some special high-temperature-output water application occasions or the blank of extremely low-temperature operation, and in the existing high-water-temperature-output heat pump products in the industry, part of the high-water-temperature-output heat pump products can only be applied to a multi-split system and can not achieve defrosting by self, and part of the high-water-temperature-output heat pump products can be used for preparing high-temperature hot water due to the addition of the cascade circulation, but the energy efficiency under most operation conditions is poor.
Therefore, how to provide a cascade heat pump circulation system capable of improving energy efficiency on the basis of improving the outlet water temperature is a technical problem to be solved urgently at present.
Disclosure of Invention
The embodiment of the invention provides a cascade heat pump circulating system, which is used for solving the technical problem of poor energy efficiency of cascade circulation in the prior art.
The system comprises:
the primary refrigerant circulating loop comprises an evaporative condenser and a primary condenser, and is used for exchanging heat with water flowing through the primary condenser based on a first refrigerant and/or exchanging heat with a second refrigerant flowing through the evaporative condenser based on the first refrigerant;
the secondary refrigerant circulation loop comprises the evaporative condenser and a secondary condenser and is used for absorbing heat transferred by the first refrigerant from the evaporative condenser based on the second refrigerant and transferring heat to water flowing through the secondary condenser based on the second refrigerant;
the water circulation loop is used for enabling water to absorb heat of the first refrigerant in the primary condenser so as to enable the water temperature to reach a first water temperature, or enabling the water to absorb heat of the second refrigerant in the secondary condenser so as to enable the water temperature to reach a second water temperature, or enabling the water to absorb heat of the first refrigerant in the primary condenser and enable the water to absorb heat of the second refrigerant in the secondary condenser so as to enable the water temperature to reach the second water temperature;
wherein the second water temperature is higher than the first water temperature.
Through using above technical scheme, overlapping heat pump circulation system includes one-level refrigerant circulation circuit, second grade refrigerant circulation circuit and water circulation circuit, and this system can prepare well warm water based on one-level refrigerant circulation circuit, prepares high-temperature water based on one-level refrigerant circulation circuit and second grade refrigerant circulation circuit, has improved the efficiency of preparing high-temperature water to improve the system efficiency on the basis of improving out water temperature.
Correspondingly, the invention also provides a control method of the cascade heat pump circulating system, which is applied to the cascade heat pump circulating system, and the method comprises the following steps:
if an instruction sent by a user to enter a high-efficiency heating mode is received and the water inlet temperature of the water circulation loop is lower than a first preset temperature, starting the water circulation loop, enabling water to flow through the primary condenser and not flow through the secondary condenser, and controlling the primary refrigerant circulation loop to enter the first preset mode;
when the temperature of the inlet water reaches a second preset temperature, switching the water circulation loop to enable the water to flow through the secondary condenser without flowing through the primary condenser or enable the water to flow through the primary condenser and the secondary condenser, and starting the secondary refrigerant circulation loop;
wherein the evaporative condenser and the primary condenser operate as condensers in the first preset mode.
By applying the technical scheme, in the cascade heat pump circulating system, the primary refrigerant circulating loop and the secondary refrigerant circulating loop are started in stages according to the water inlet temperature of the water circulating loop, so that the energy efficiency of the cascade heat pump circulating system is improved on the basis of improving the water outlet temperature.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic structural diagram illustrating a cascade heat pump cycle system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a cascade heat pump cycle system according to another embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating a manner of producing warm water according to an embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a high-temperature water producing method according to an embodiment of the present invention;
FIG. 5 shows a schematic diagram of a defrost cycle in accordance with an embodiment of the present invention;
fig. 6 is a schematic structural view illustrating a cascade heat pump cycle system according to still another embodiment of the present invention;
FIG. 7 is a diagram illustrating a one-to-one connection method according to an embodiment of the present invention;
FIG. 8 is a diagram illustrating a multi-split online mode according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of a multi-split connection method according to another embodiment of the present invention;
fig. 10 is a schematic view showing a configuration of a cascade heat pump cycle according to still another embodiment of the present invention;
fig. 11 is a schematic structural view illustrating a cascade heat pump cycle according to still another embodiment of the present invention;
fig. 12 is a schematic flow chart illustrating a control method of a cascade heat pump cycle system according to an embodiment of the present invention;
101, a primary compressor; 102. a heat exchanger; 103. a four-way valve; 104. a primary throttling assembly; 1041. an indoor throttle valve; 1042. an outdoor throttle valve; 201. a secondary compressor; 202. an evaporative condenser; 203. a secondary condenser; 204. a second throttling assembly; 205. a first-stage condenser; 301. a first temperature sensor; 302. a second temperature sensor; 303. a third temperature sensor; 304. a fourth temperature sensor; 305. a fifth temperature sensor; 401. an electric three-way valve; 402. a water pump; 403. a sixth temperature sensor; 404. and a seventh temperature sensor.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
An embodiment of the present application provides a cascade heat pump cycle system, as shown in fig. 1, including:
the primary refrigerant circulation loop 100 comprises an evaporative condenser and a primary condenser, and is used for exchanging heat with water flowing through the primary condenser based on a first refrigerant and/or exchanging heat with a second refrigerant flowing through the evaporative condenser based on the first refrigerant;
a secondary refrigerant circulation circuit 200 including the evaporative condenser and a secondary condenser, for absorbing heat transferred from the evaporative condenser based on the second refrigerant, and transferring heat to water flowing through the secondary condenser based on the second refrigerant;
a water circulation loop 300, configured to enable water to absorb heat of the first refrigerant in the primary condenser to enable the water temperature to reach a first water temperature, or to enable water to absorb heat of the second refrigerant in the secondary condenser to enable the water temperature to reach a second water temperature, or to enable water to absorb heat of the first refrigerant in the primary condenser and enable water to absorb heat of the second refrigerant in the secondary condenser to enable the water temperature to reach the second water temperature;
wherein the second water temperature is higher than the first water temperature.
In this embodiment, the primary refrigerant circulation loop circulates a first refrigerant, and is used for producing water with a first water temperature, i.e., medium-temperature water; the secondary refrigerant circulation loop circulates a second refrigerant and is used for preparing water with a second water temperature, namely high-temperature water. The evaporative condenser is connected with the primary refrigerant circulation loop and the secondary refrigerant circulation loop.
In fig. 1, the arrows may represent the direction of heat transfer during heating, when water with a first water temperature is prepared, the water in the water circulation loop flows through the evaporative condenser and the primary condenser in the primary refrigerant circulation loop, and does not flow through the secondary condenser, and the first refrigerant exchanges heat with the water flowing through the primary condenser;
when water with a second water temperature is prepared, according to different structures, the method can be divided into two situations, wherein one situation is that water in a water circulation loop flows through an evaporative condenser and a secondary condenser in a secondary refrigerant circulation loop and does not flow through a primary condenser, so that heat is transferred to the water flowing through the secondary condenser based on a second refrigerant after a first refrigerant exchanges heat with the second refrigerant flowing through the evaporative condenser; the other type is that water in the water circulation loop flows through a first-stage condenser in the first-stage refrigerant circulation loop and flows through an evaporative condenser and a second-stage condenser in the second-stage refrigerant circulation loop, the first refrigerant exchanges heat with a second refrigerant flowing through the evaporative condenser, and the water can absorb the heat of the first refrigerant in the first-stage condenser and the heat of the second refrigerant in the second-stage condenser.
In some embodiments of the present application, the first water temperature may be 40-60 ℃ and the second water temperature may be 60-80 ℃.
For reliable defrosting, in some embodiments of the present application, the water circulation loop is further configured to:
and transferring heat from the water to the first refrigerant in the primary condenser to increase the temperature of the first refrigerant.
In this embodiment, the first-stage refrigerant circulation loop further includes a heat exchanger, when hot water is produced, the heat exchanger operates with the evaporator, when outdoor temperature is low, the heat exchanger may frost, and further hot water production efficiency is affected, heat is transferred to the first refrigerant through water, the temperature of the first refrigerant can be increased, and the defrosting speed of the heat exchanger can be increased in a defrosting mode.
In order to improve the reliability of the primary refrigerant circulation circuit, in some embodiments of the present invention, as shown in fig. 2 and 10, the primary refrigerant circulation circuit further includes a primary compressor 101, a four-way valve 103, a heat exchanger 102, and a primary throttling assembly 104, wherein,
as shown in fig. 2, the primary throttle assembly 104 is respectively connected to the first port of the primary condenser 205 and the first port of the heat exchanger 102, two ends of the four-way valve 103 are respectively connected to the first port of the evaporative condenser 202 and the second port of the heat exchanger 102, the other two ends of the four-way valve 103 are respectively connected to the outlet and the inlet of the primary compressor 101, the second port of the primary condenser 205 is connected to the second port of the evaporative condenser 202, or,
the position of the secondary refrigerant circulation loop is changed, as shown in fig. 10, the first throttling assembly 104 is respectively connected to the second interface of the evaporative condenser 202 and the first interface of the heat exchanger 102, two ends of the four-way valve 103 are respectively connected to the second interface of the primary condenser 205 and the second interface of the heat exchanger 102, the other two ends of the four-way valve 103 are respectively connected to the outlet and the inlet of the primary compressor 101, and the first interface of the primary condenser 205 is connected to the first interface of the evaporative condenser 202.
In some embodiments of the present application, the heat exchanger 102 is a finned tube heat exchanger.
In order to improve the reliability of the secondary refrigerant circulation circuit, in some embodiments of the present invention, as shown in fig. 2, the secondary refrigerant circulation circuit further includes a secondary compressor 201 and a secondary throttling assembly 204, wherein,
the secondary throttle component 204 is respectively connected with the first interface of the secondary condenser 203 and the third interface of the evaporative condenser 202, the outlet of the secondary compressor 201 is connected with the second interface of the secondary condenser 203, and the inlet of the secondary compressor 201 is connected with the fourth interface of the evaporative condenser 202.
In order to improve the reliability of the water circulation circuit, in some embodiments of the present application, as shown in fig. 2, 10 and 11, the water circulation circuit includes an inlet pipe, a water pump 402, an electric three-way valve 401 and an outlet pipe, wherein,
as shown in fig. 2, an inlet of the water pump 402 is connected to the water inlet pipe, an outlet of the water pump 402 is connected to an inlet of the electric three-way valve 401, a first outlet of the electric three-way valve 401 is connected to the third port of the primary condenser 205, a second outlet of the electric three-way valve 401 is connected to the third port of the secondary condenser 203, a fourth port of the primary condenser 205 and a fourth port of the secondary condenser 203 are connected to the water outlet pipe, or,
changing the position of the electric three-way valve, as shown in fig. 10 and 11, the inlet of the water pump 402 is connected to the water inlet pipe, the outlet of the water pump 402 is connected to the third port of the first-stage condenser 205, the fourth port of the first-stage condenser 205 is connected to the inlet of the electric three-way valve 401, the first outlet of the electric three-way valve 401 is connected to the third port of the second-stage condenser 203, and the fourth port of the second-stage condenser 203 and the second outlet of the electric three-way valve 401 are connected to the water outlet pipe.
In some embodiments of the present application, as shown in fig. 6, the system is divided into an outdoor unit part and an indoor unit part, the primary throttle assembly includes an indoor throttle valve 1041 and an outdoor throttle valve 1042, the primary compressor 101, the four-way valve 103, the heat exchanger 102, and the outdoor throttle valve 1042 are disposed in the outdoor unit part, the water pump 402, the electric three-way valve 401, the primary condenser 205, the evaporative condenser 202, the indoor throttle valve 1041, the secondary throttle assembly 204, the secondary compressor 201, and the secondary condenser 203 are disposed in the indoor unit part.
In this embodiment, the cascade heat pump cycle system may be a unit of one-to-one type, that is, one outdoor unit is connected to one cascade indoor unit with a higher outlet water temperature, as shown in fig. 7.
The overlapping heat pump circulating system can be a multi-split unit, and one outdoor unit is connected with a plurality of overlapping indoor units with high water outlet temperature, as shown in fig. 8.
The cascade heat pump circulation system can also be connected with other indoor units (such as an indoor unit for adjusting the ambient temperature) to form a multi-split multi-connected unit, as shown in fig. 9.
In order to improve the reliability of the system, in some embodiments of the present application, as shown in fig. 2, the system further comprises a first temperature sensor 301, a second temperature sensor 302, a third temperature sensor 303, a fourth temperature sensor 304, a fifth temperature sensor 305, a sixth temperature sensor 403, and a seventh temperature sensor 404, wherein,
the first temperature sensor 301 is disposed between the four-way valve 103 and the evaporative condenser 202, the second temperature sensor 302 is disposed between the primary condenser 205 and the evaporative condenser 202, the third temperature sensor 303 is disposed between the primary condenser 205 and the first throttling assembly 104, the fourth temperature sensor 304 is disposed at the outlet of the secondary compressor 201, the fifth temperature sensor 305 is disposed between the secondary condenser 203 and the second throttling assembly 204, the sixth temperature sensor 403 is disposed at the outlet of the water pump 402, and the seventh temperature sensor 404 is disposed at the water outlet pipe.
Through using above technical scheme, overlapping heat pump cycle system includes: the primary refrigerant circulating loop comprises an evaporative condenser and a primary condenser, and is used for exchanging heat with water flowing through the primary condenser based on a first refrigerant and/or exchanging heat with a second refrigerant flowing through the evaporative condenser based on the first refrigerant; the secondary refrigerant circulation loop comprises the evaporative condenser and a secondary condenser and is used for absorbing heat transferred by the first refrigerant from the evaporative condenser based on the second refrigerant and transferring heat to water flowing through the secondary condenser based on the second refrigerant; the water circulation loop is used for enabling water to absorb heat of the first refrigerant in the primary condenser so as to enable the water temperature to reach a first water temperature, or enabling the water to absorb heat of the second refrigerant in the secondary condenser so as to enable the water temperature to reach a second water temperature, or enabling the water to absorb heat of the first refrigerant in the primary condenser and enable the water to absorb heat of the second refrigerant in the secondary condenser so as to enable the water temperature to reach the second water temperature; the system can prepare medium-temperature water based on the first-stage refrigerant circulation loop, and prepare high-temperature water based on the first-stage refrigerant circulation loop and the second-stage refrigerant circulation loop, so that the efficiency of preparing the high-temperature water is improved, and the energy efficiency is improved on the basis of improving the water outlet temperature.
An embodiment of the present application further provides a method for controlling a cascade heat pump cycle system, which is applied to the cascade heat pump cycle system described above, and as shown in fig. 12, the method includes the following steps:
step S101, if an instruction sent by a user to enter a high-efficiency heating mode is received and the water inlet temperature of the water circulation loop is lower than a first preset temperature, the water circulation loop is started, water flows through the primary condenser and does not flow through the secondary condenser, and the primary refrigerant circulation loop is controlled to enter the first preset mode.
Wherein the evaporative condenser and the primary condenser operate as condensers in the first preset mode.
In this embodiment, the operation mode of the cascade heat pump cycle system includes a high-efficiency heating mode, if an instruction of entering the high-efficiency heating mode sent by a user is received, the water inflow temperature of the water circulation loop is obtained, if the water temperature is lower than a first preset temperature, the primary refrigerant circulation loop is started first to heat water, that is, the water circulation loop is started to enable water to flow through the primary condenser without flowing through the secondary condenser, and the primary refrigerant circulation loop is controlled to enter the first preset mode, and the evaporative condenser and the primary condenser operate as condensers in the first preset mode.
Step S102, when the inlet water temperature reaches a second preset temperature, switching the water circulation loop to enable water to flow through the secondary condenser and not to flow through the primary condenser or enable water to flow through the primary condenser and the secondary condenser, and starting the secondary refrigerant circulation loop
In this embodiment, when the water temperature reaches the second preset temperature, the secondary refrigerant circulation loop is started to heat the water, and according to different system structures, the water circulation loop can be switched in two ways, one is the structure shown in fig. 2, so that the water flows through the secondary condenser 203 and does not flow through the primary condenser 205; in the other configuration, as shown in fig. 10 or 11, water is passed through the first-stage condenser 205 and the second-stage condenser 203, and the second-stage refrigerant circulation circuit is started. According to the difference of the water inlet temperature, the primary refrigerant circulation loop and the secondary refrigerant circulation loop are started in stages, so that the system energy efficiency is improved.
In some embodiments of the present application, the second predetermined temperature is greater than the first predetermined temperature, the first predetermined temperature can be a deg.C, and the second predetermined temperature can be (a +2) deg.C, wherein a is greater than or equal to 40 deg.C and less than or equal to 60 deg.C.
To further enhance the user experience, in some embodiments of the present application, the method further comprises:
and if an instruction of entering a quick hot water mode sent by a user is received, starting the water circulation loop, enabling water to flow through the secondary condenser without flowing through the primary condenser or enabling water to flow through the primary condenser and the secondary condenser, controlling the primary refrigerant circulation loop to enter the first preset mode, and starting the secondary refrigerant circulation loop.
In this embodiment, the operation mode of the cascade heat pump circulation system further includes a fast hot water mode, and if an instruction for entering the fast hot water mode is received from a user, the primary refrigerant circulation loop and the secondary refrigerant circulation loop are simultaneously started, and according to different system structures, the water circulation loop can be started in two ways, one is the structure shown in fig. 2, so that water flows through the secondary condenser 203 and does not flow through the primary condenser 205; the other is a structure as shown in fig. 10 or fig. 11, which makes water flow through a primary condenser 205 and a secondary condenser 203. And controlling the primary refrigerant circulation loop to enter a first preset mode, and starting the secondary refrigerant circulation loop. Because the primary refrigerant circulation loop and the secondary refrigerant circulation loop work, larger heating capacity can be obtained.
For reliable defrosting, in some embodiments of the present application, the method further comprises:
if a defrosting instruction sent by a user is received, starting the water circulation loop, enabling water to flow through the primary condenser and not flow through the secondary condenser, and controlling the primary refrigerant circulation loop to enter a second preset mode;
and the evaporative condenser and the primary condenser work as evaporators in the second preset mode.
In this embodiment, the first-stage refrigerant circulation circuit includes a heat exchanger, and if a defrosting instruction sent by a user is received, the water circulation circuit is started, water flows through the first-stage condenser without flowing through the second-stage condenser, the first-stage refrigerant circulation circuit is operated in a second preset mode, and the evaporative condenser and the first-stage condenser operate as an evaporator in the second preset mode. Water is introduced into the first-stage condenser, the first refrigerant absorbs heat in the water, and the first-stage compressor inputs power by utilizing the absorbed part of heat to complete defrosting of the heat exchanger.
By applying the technical scheme, in the cascade heat pump circulating system, if an instruction of entering the high-efficiency heating mode sent by a user is received and the water inlet temperature of the water circulating loop is lower than a first preset temperature, the water circulating loop is started, water flows through the primary condenser without flowing through the secondary condenser, and the primary refrigerant circulating loop is controlled to enter the first preset mode; when the temperature of the inlet water reaches a second preset temperature, switching the water circulation loop to enable the water to flow through the secondary condenser without flowing through the primary condenser or enable the water to flow through the primary condenser and the secondary condenser, and starting the secondary refrigerant circulation loop; the evaporative condenser and the first-stage condenser work as condensers in the first preset mode, and the first-stage refrigerant circulation loop and the second-stage refrigerant circulation loop are started in stages according to the water inlet temperature, so that the energy efficiency of the cascade heat pump circulation system is improved on the basis of improving the water outlet temperature.
In order to further illustrate the technical idea of the present invention, the technical solution of the present invention will now be described with reference to specific application scenarios.
The embodiment of the application provides a cascade heat pump circulation system, including one-level refrigerant circulation circuit, second grade refrigerant circulation circuit and water circulation circuit, as shown in fig. 2, the concrete structure is as follows:
the first-stage refrigerant circulation loop comprises an evaporative condenser 202, a first-stage condenser 205, a first-stage compressor 101, a four-way valve 103, a heat exchanger 102 and a first-stage throttling assembly 104, the first-stage throttling assembly 104 is respectively connected with a first interface of the first-stage condenser 205 and a first interface of the heat exchanger 102, two ends of the four-way valve 103 are respectively connected with the first interface of the evaporative condenser 202 and a second interface of the heat exchanger 102, the other two ends of the four-way valve 103 are respectively connected with an outlet and an inlet of the first-stage compressor 101, and the second interface of the first-stage condenser 205 is connected with the second interface of the evaporative condenser 202.
The secondary refrigerant circulation loop comprises an evaporative condenser 202, a secondary condenser 203, a secondary compressor 201 and a secondary throttling component 204, wherein the secondary throttling component 204 is respectively connected with a first interface of the secondary condenser 203 and a third interface of the evaporative condenser 202, an outlet of the secondary compressor 201 is connected with a second interface of the secondary condenser 203, and an inlet of the secondary compressor 201 is connected with a fourth interface of the evaporative condenser 202.
The water circulation loop comprises a water inlet pipeline, a water pump 402, an electric three-way valve 401 and a water outlet pipeline, wherein an inlet of the water pump 402 is connected with the water inlet pipeline, an outlet of the water pump 402 is connected with an inlet of the electric three-way valve 401, a first outlet of the electric three-way valve 401 is connected with a third interface of the first-stage condenser 205, a second outlet of the electric three-way valve 401 is connected with a third interface of the second-stage condenser 203, and a fourth interface of the first-stage condenser 205 and a fourth interface of the second-stage condenser 203 are connected with the water outlet pipeline in a sharing mode.
The cascade heat pump circulating system can prepare medium-temperature water and high-temperature water.
As shown in fig. 3, the medium-temperature water (i.e. water with a first water temperature) preparation principle comprises: the first-stage compressor 101 is operated, the second-stage compressor 201 is not operated, the second-stage refrigerant circulation loop does not work, only the first-stage refrigerant circulation loop works, the electric three-way valve 401 is in a straight-through state, the water pump 402 is operated, and water is introduced into the first-stage condenser 205 and does not enter the second-stage condenser 203. At this time, the exhaust gas of the primary compressor passes through the evaporative condenser 202, but since the secondary refrigerant circulation loop does not work, there is no heat exchange in the evaporative condenser 202, the first refrigerant and water exchange in the primary condenser 205, and at this time, similar to the conventional heat pump system, the hot water up to about 60 ℃ can be prepared.
As shown in fig. 4, the high-temperature water (i.e., water of the second water temperature) preparation principle includes: the first-stage compressor 101 operates, the second-stage compressor 201 also operates, the first-stage refrigerant circulation loop and the second-stage refrigerant circulation loop both work, the electric three-way valve 401 is in a bent state, the water pump 402 operates, and water is introduced into the second-stage condenser 203 and does not pass through the first-stage condenser 205. At this time, the whole refrigerant system is in a cascade circulation mode, the first refrigerant in the primary refrigerant circulation loop emits heat in the evaporative condenser 202, the second refrigerant in the secondary refrigerant circulation loop absorbs heat from the evaporative condenser 202, and finally the second refrigerant emits heat in the secondary condenser 203 to finish heating water. Because of the existence of two-stage refrigerant circulation loops, the capacity of preparing high-temperature water is further enhanced, the highest outlet water temperature is closely related to the refrigerant applicable to the two-stage refrigerant circulation loop, and if the second refrigerant is R134a, the highest outlet water temperature can reach 80 ℃.
The working modes of the cascade heat pump circulating system comprise:
1. high-efficiency heating mode: the preparation of the medium-temperature water is combined with the preparation of the high-temperature water, so that the heating efficiency is improved. When the temperature detected by the water inlet temperature sensor is lower than 50 ℃, the heating can be completed by preferentially using the first-stage refrigerant circulation loop, the second-stage compressor of the second-stage refrigerant circulation loop is not started, the higher heating efficiency can be achieved at the moment, after the temperature detected by the water inlet temperature sensor exceeds 52 ℃ (return difference needs to be ensured), the second-stage compressor is started, the electric three-way valve is switched from straight-through to bent-through, and the overlapping heating circulation is started until the water is heated to the target water outlet temperature. According to the difference of the water inlet temperature, the primary refrigerant circulation loop and the secondary refrigerant circulation loop are started in stages, and the system energy efficiency can be greatly improved.
2. A rapid hot water mode: and the electric three-way valve keeps a bent-through state until the target outlet water temperature is reached. The fast hot water mode is a user comfort priority, and as the two-stage compressor is working, the amount of heating available is greater.
3. Defrosting mode: as shown in fig. 5, the normal operation of the first-stage compressor 101 is maintained, the four-way valve 103 is reversed to enable the exhaust gas of the first-stage compressor 101 to directly enter the heat exchanger 102, the second-stage compressor 201 does not work, the first-stage condenser 205 is changed into an evaporator, the water pump 402 is opened, the electric three-way valve 401 is in a straight-through state, water is introduced into the first-stage condenser 205, the first refrigerant absorbs heat from water, and defrosting of the heat exchanger 102 is completed by utilizing the absorbed part of heat and the input power of the first-stage compressor 101.
The embodiment of the present application further provides a cascade heat pump circulation system, which is different from the system structure in fig. 2 in that the position of a secondary refrigerant circulation loop and the position of an electric three-way valve are changed, as shown in fig. 10, the first throttling component 104 is respectively connected to the second interface of the evaporative condenser 202 and the first interface of the heat exchanger 102, two ends of the four-way valve 103 are respectively connected to the second interface of the primary condenser 205 and the second interface of the heat exchanger 102, the other two ends of the four-way valve 103 are respectively connected to the outlet and the inlet of the primary compressor 101, the first interface of the primary condenser 205 is connected to the first interface of the evaporative condenser 202, the inlet of the water pump 402 is connected to the water inlet pipe, the outlet of the water pump 402 is connected to the third interface of the primary condenser 205, the fourth interface of the primary condenser 205 is connected to the inlet of the electric three-way valve 401, a first outlet of the electric three-way valve 401 is connected with a third port of the secondary condenser 203, and a fourth port of the secondary condenser 203 and a second outlet of the electric three-way valve 401 are connected with the water outlet pipeline.
The embodiment of the present application further provides a cascade heat pump circulation system, different from the system structure in fig. 2, the position of the electric three-way valve is changed, as shown in fig. 11, the inlet connection of the water pump 402 is the water inlet pipe, the outlet connection of the water pump 402 is the third interface of the first-level condenser 205, the fourth interface connection of the first-level condenser 205 is the inlet of the electric three-way valve 401, the first outlet connection of the electric three-way valve 401 is the third interface of the second-level condenser 203, the fourth interface of the second-level condenser 203 and the second outlet of the electric three-way valve 401 are connected to the water outlet pipe.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not necessarily depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (10)
1. A cascade heat pump cycle system, comprising:
the primary refrigerant circulating loop comprises an evaporative condenser and a primary condenser, and is used for exchanging heat with water flowing through the primary condenser based on a first refrigerant and/or exchanging heat with a second refrigerant flowing through the evaporative condenser based on the first refrigerant;
the secondary refrigerant circulation loop comprises the evaporative condenser and a secondary condenser and is used for absorbing heat transferred by the first refrigerant from the evaporative condenser based on the second refrigerant and transferring heat to water flowing through the secondary condenser based on the second refrigerant;
the water circulation loop is used for enabling water to absorb heat of the first refrigerant in the primary condenser so as to enable the water temperature to reach a first water temperature, or enabling the water to absorb heat of the second refrigerant in the secondary condenser so as to enable the water temperature to reach a second water temperature, or enabling the water to absorb heat of the first refrigerant in the primary condenser and enable the water to absorb heat of the second refrigerant in the secondary condenser so as to enable the water temperature to reach the second water temperature;
wherein the second water temperature is higher than the first water temperature.
2. The system of claim 1, wherein the water circulation loop is further configured to:
and transferring heat from the water to the first refrigerant in the primary condenser to increase the temperature of the first refrigerant.
3. The system of claim 2, wherein the primary refrigerant circulation loop further comprises a primary compressor, a four-way valve, a heat exchanger, and a primary throttling assembly, wherein,
the first-stage throttling component is respectively connected with a first interface of the first-stage condenser and a first interface of the heat exchanger, two ends of the four-way valve are respectively connected with a first interface of the evaporative condenser and a second interface of the heat exchanger, the other two ends of the four-way valve are respectively connected with an outlet and an inlet of the first-stage compressor, the second interface of the first-stage condenser is connected with a second interface of the evaporative condenser, or,
the first throttling assembly is respectively connected with the second interface of the evaporative condenser and the first interface of the heat exchanger, two ends of the four-way valve are respectively connected with the second interface of the primary condenser and the second interface of the heat exchanger, the other two ends of the four-way valve are respectively connected with the outlet and the inlet of the primary compressor, and the first interface of the primary condenser is connected with the first interface of the evaporative condenser.
4. The system of claim 3, wherein the secondary refrigerant circulation loop further comprises a secondary compressor and a secondary throttling assembly, wherein,
the second grade throttling component is respectively connected with the first interface of the second grade condenser and the third interface of the evaporative condenser, the outlet of the second grade compressor is connected with the second interface of the second grade condenser, and the inlet of the second grade compressor is connected with the fourth interface of the evaporative condenser.
5. The system of claim 4, wherein the water circulation loop comprises an inlet conduit, a water pump, an electrically operated three-way valve, and an outlet conduit, wherein,
the inlet of the water pump is connected with the water inlet pipeline, the outlet of the water pump is connected with the inlet of the electric three-way valve, the first outlet of the electric three-way valve is connected with the third interface of the primary condenser, the second outlet of the electric three-way valve is connected with the third interface of the secondary condenser, the fourth interface of the primary condenser and the fourth interface of the secondary condenser are connected with the water outlet pipeline together, or,
the entry linkage of water pump the inlet channel, the exit linkage of water pump the third interface of one-level condenser, the fourth interface connection of one-level condenser the entry of electric three-way valve, the first exit linkage of electric three-way valve the third interface of second grade condenser, the fourth interface of second grade condenser with the second export of electric three-way valve connects altogether outlet conduit.
6. The system of claim 5, wherein the system is divided into an outdoor unit part and an indoor unit part, the primary throttle assembly includes an indoor throttle valve and an outdoor throttle valve, the primary compressor, the four-way valve, the heat exchanger and the outdoor throttle valve are provided in the outdoor unit part, the water pump, the electric three-way valve, the primary condenser, the evaporative condenser, the indoor throttle valve, the secondary throttle assembly, the secondary compressor and the secondary condenser are provided in the indoor unit part.
7. The system of claim 5, further comprising a first temperature sensor, a second temperature sensor, a third temperature sensor, a fourth temperature sensor, a fifth temperature sensor, a sixth temperature sensor, a seventh temperature sensor, wherein,
the first temperature sensor is arranged between the four-way valve and the evaporative condenser, the second temperature sensor is arranged between the first-stage condenser and the evaporative condenser, the third temperature sensor is arranged between the first-stage condenser and the first throttling component, the fourth temperature sensor is arranged at the outlet of the second-stage compressor, the fifth temperature sensor is arranged between the second-stage condenser and the second throttling component, the sixth temperature sensor is arranged at the outlet of the water pump, and the seventh temperature sensor is arranged at the water outlet pipeline.
8. A method for controlling a cascade heat pump cycle, which is applied to the cascade heat pump cycle according to any one of claims 1 to 7, the method comprising:
if an instruction sent by a user to enter a high-efficiency heating mode is received and the water inlet temperature of the water circulation loop is lower than a first preset temperature, starting the water circulation loop, enabling water to flow through the primary condenser and not flow through the secondary condenser, and controlling the primary refrigerant circulation loop to enter the first preset mode;
when the temperature of the inlet water reaches a second preset temperature, switching the water circulation loop to enable the water to flow through the secondary condenser without flowing through the primary condenser or enable the water to flow through the primary condenser and the secondary condenser, and starting the secondary refrigerant circulation loop;
wherein the evaporative condenser and the primary condenser operate as condensers in the first preset mode.
9. The method of claim 8, wherein the method further comprises:
and if an instruction of entering a quick hot water mode sent by a user is received, starting the water circulation loop, enabling water to flow through the secondary condenser without flowing through the primary condenser or enabling water to flow through the primary condenser and the secondary condenser, controlling the primary refrigerant circulation loop to enter the first preset mode, and starting the secondary refrigerant circulation loop.
10. The method of claim 8, wherein the method further comprises:
if a defrosting instruction sent by a user is received, starting the water circulation loop, enabling water to flow through the primary condenser and not flow through the secondary condenser, and controlling the primary refrigerant circulation loop to enter a second preset mode;
and the evaporative condenser and the primary condenser work as evaporators in the second preset mode.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
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| CN202110639064.6A CN113531935A (en) | 2021-06-08 | 2021-06-08 | Overlapping heat pump circulating system and control method |
| EP22819590.5A EP4354048A1 (en) | 2021-06-08 | 2022-06-08 | Heat pump system and control method therefor |
| CN202280008879.7A CN116670436A (en) | 2021-06-08 | 2022-06-08 | Heat pump system and control method thereof |
| PCT/CN2022/097721 WO2022257993A1 (en) | 2021-06-08 | 2022-06-08 | Heat pump system and control method therefor |
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| CN202110639064.6A CN113531935A (en) | 2021-06-08 | 2021-06-08 | Overlapping heat pump circulating system and control method |
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Application publication date: 20211022 |