A cascade temperature control system

Abstract

The utility model proposes a cascade temperature control system, including a primary temperature control system, a secondary temperature control system, a first heat exchanger, a second heat exchanger and an intermediate heat exchanger, wherein the medium channels of the first heat exchanger and the second heat exchanger are arranged in isolation, and the water channels of the first heat exchanger and the second heat exchanger are arranged in parallel; the primary temperature control system and the secondary temperature control system perform heat exchange through the intermediate heat exchanger; the medium channel of the first heat exchanger is connected to the medium channel of the primary temperature control system through a valve; the medium channel of the second heat exchanger is connected to the medium channel of the secondary temperature control system. By connecting the water channels in parallel, the water channel temperatures in the first heat exchanger and the second heat exchanger can be heat-transferred, and when the primary temperature control system needs to be defrosted, the medium absorbs heat from the first heat exchanger, which can facilitate the defrosting of the evaporator in the primary temperature control system.

Description

Technical Field

[0001] The utility model relates to the technical field of temperature control, in particular to a cascade temperature control system. Background Art

[0002] Air source heat pumps are increasingly used for heating in cold areas in the north. According to the characteristics of heating, when the ambient temperature is relatively low, buildings generally require a higher water supply temperature to meet heating needs. The cascade heat pump can provide a higher water outlet temperature at low temperatures through a two-stage compressor cascade design to meet the heating or hot water needs at low temperatures. The fin evaporator of the cascade heat pump absorbs heat from the environment and will frost at low temperatures. The existing defrosting method defrosts by absorbing heat from the high-temperature water side, and the system stability is poor. Absorbing heat from high-temperature water will cause the compressor evaporation temperature to be too high, exceeding the compressor operating range, and causing damage to the compressor.

[0003] Therefore, the technical problem that the present application needs to solve is how to defrost the evaporator stably and efficiently. Utility Model Content

[0004] In order to solve the above technical problems, the utility model proposes a cascade temperature control system. By connecting water channels in parallel, the water channel temperatures in the first heat exchanger and the second heat exchanger can be heat transferred. When the primary temperature control system needs to be defrosted, the medium absorbs heat from the first heat exchanger, which can facilitate the defrosting of the evaporator in the primary temperature control system.

[0005] Specifically, the utility model proposes a cascade temperature control system, including a primary temperature control system, a secondary temperature control system, a first heat exchanger, a second heat exchanger and an intermediate heat exchanger, wherein the medium channels of the first heat exchanger and the second heat exchanger are arranged in isolation, and the water channels of the first heat exchanger and the second heat exchanger are arranged in parallel; the primary temperature control system and the secondary temperature control system perform heat exchange through the intermediate heat exchanger;

[0006] The medium channel of the first heat exchanger is connected to the medium channel of the primary temperature control system through a valve;

[0007] The medium channel of the second heat exchanger is connected to the medium channel of the secondary temperature control system.

[0008] Preferably, the intermediate heat exchanger has a first medium channel and a second medium channel, the first medium channel is connected to the primary temperature control system, and the second medium channel is connected to the secondary temperature control system.

[0009] Preferably, the first-stage temperature control system includes: a first-stage compressor, a four-way valve and a third heat exchanger, the exhaust port of the first-stage compressor is connected to the first interface of the four-way valve, the second interface of the four-way valve is connected to one end of the third heat exchanger, the other end of the third heat exchanger is connected to one end of the first medium channel, the fourth interface of the four-way valve is connected to the other end of the first medium channel through a first one-way valve, and the third interface of the four-way valve is connected to the air inlet of the first-stage compressor.

[0010] Preferably, the fourth interface of the four-way valve and the other end of the first media channel are connected through a first pipeline, and the first one-way valve is provided on the first pipeline, and the first one-way valve is used to allow the medium of the fourth interface to flow to the other end of the first media channel.

[0011] Preferably, one end of the first heat exchanger is connected to the first pipeline through a second pipeline, and the second pipeline is located on the inflow side of the first one-way valve; the other end of the first heat exchanger is connected to the first pipeline through a third pipeline, and the third pipeline is located on the outflow side of the first one-way valve.

[0012] Preferably, the valve is a second one-way valve, and the valve is arranged on the second pipeline, and the second one-way valve is used to allow the medium in the first heat exchanger to flow to the fourth interface of the four-way valve.

[0013] Preferably, an economizer is provided between the third heat exchanger and the intermediate heat exchanger, and a third medium channel and a fourth medium channel are provided on the economizer, the other end of the third heat exchanger is connected to one end of the fourth medium channel through a fourth pipeline, and the other end of the fourth medium channel is connected to one end of the first medium channel through a fifth pipeline;

[0014] A branch pipe connected to the third medium channel is installed on the fourth pipeline, and an end of the third medium channel away from the branch pipe is connected to the air supply port of the first-stage compressor through a sixth pipeline.

[0015] Preferably, a first electronic expansion valve is installed on the fourth pipeline; and a second electronic expansion valve is installed on the branch pipe.

[0016] Preferably, the secondary temperature control system includes a secondary compressor, the exhaust port of the secondary compressor is connected to one end of the second heat exchanger, the other end of the second heat exchanger is connected to one end of the second media channel, and the other end of the second media channel is connected to the air inlet of the secondary compressor.

[0017] Preferably, a third electronic expansion valve is provided between the other end of the second heat exchanger and one end of the second medium channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the drawings required to be used in the embodiments or the description of the prior art will be briefly introduced below.

[0019] Figure 1 This embodiment proposes a working schematic diagram of a cascade temperature control system in a heating mode;

[0020] Figure 2 This embodiment proposes a working schematic diagram of a cascade temperature control system in a defrosting mode;

[0021] Figure 3 yes Figure 1 Schematic diagram of the local enlarged structure at point A in the middle.

[0022] The reference numerals in the accompanying drawings are as follows:

[0023] 11-primary temperature control system; 12-secondary temperature control system; 13-first heat exchanger; 14-second heat exchanger; 15-intermediate heat exchanger; 16-primary compressor; 17-four-way valve; 18-third heat exchanger; 19-first interface; 20-second interface; 21-third interface; 22-fourth interface; 23-first pipeline; 24-first one-way valve; 25-second pipeline; 26-second one-way valve; 27-economizer; 28-fourth pipeline; 29-fifth pipeline; 30-branch pipe; 31-sixth pipeline; 32-first electronic expansion valve; 33-second electronic expansion valve; 34-secondary compressor; 35-third electronic expansion valve; 36-third pipeline; 37-first gas-liquid separator; 38-first liquid storage tank; 39-second gas-liquid separator. DETAILED DESCRIPTION

[0024] The technical solution of the present application is further described below in conjunction with specific embodiments, but the present application is not limited to these embodiments.

[0025] like Figures 1 to 3 As shown, this embodiment proposes a cascade temperature control system, including a primary temperature control system 11, a secondary temperature control system 12, a first heat exchanger 13, a second heat exchanger 14 and an intermediate heat exchanger 15, the medium channels of the first heat exchanger 13 and the second heat exchanger 14 are arranged in isolation, and the water channels of the first heat exchanger 13 and the second heat exchanger 14 are arranged in parallel; the primary temperature control system 11 and the secondary temperature control system 12 perform heat exchange through the intermediate heat exchanger 15;

[0026] The medium channel of the first heat exchanger 13 is connected to the medium channel of the primary temperature control system 11 through a valve;

[0027] The medium passage of the second heat exchanger 14 is connected to the medium passage of the secondary temperature control system 12 .

[0028] The technical effect of this solution is that: this solution enables the water channel temperatures in the first heat exchanger 13 and the second heat exchanger 14 to be heat transferred by connecting the water channels in parallel. When the primary temperature control system 11 needs to be defrosted, the medium absorbs heat from the first heat exchanger 13, thereby being able to defrost the evaporator in the primary temperature control system 11 more stably.

[0029] Furthermore, the specific implementation scheme of this embodiment is as follows:

[0030] The intermediate heat exchanger 15 has a first medium channel and a second medium channel. The first medium channel is connected to the primary temperature control system 11 , and the second medium channel is connected to the secondary temperature control system 12 .

[0031] The intermediate heat exchanger 15 is a conventional device, and the first medium channel and the second medium channel are not shown in the drawings.

[0032] The intermediate heat exchanger 15 in this solution can effectively transfer the heat of the first temperature control system to the second temperature control system, so that the water channel in the second evaporator can be effectively heated to adapt to the low temperature environment.

[0033] Furthermore, the first-stage temperature control system 11 includes: a first-stage compressor 16, a four-way valve 17 and a third heat exchanger 18, the exhaust port of the first-stage compressor 16 is connected to the first interface 19 of the four-way valve 17, the second interface 20 of the four-way valve 17 is connected to one end of the third heat exchanger 18, the other end of the third heat exchanger 18 is connected to one end of the first medium channel, the fourth interface 22 of the four-way valve 17 is connected to the other end of the first medium channel through the first one-way valve 24, and the third interface 21 of the four-way valve 17 is connected to the air inlet of the first-stage compressor 16.

[0034] The third heat exchanger 18 is a cascade heat pump fin evaporator.

[0035] In this solution, the flow direction of the medium is switched and controlled by setting a four-way valve 17. In the heating mode, the first interface 19 and the fourth interface 22 of the four-way valve 17 are connected, and the second interface 20 and the third interface 21 are connected. In the defrosting mode, the first interface 19 and the second interface 20 of the four-way valve 17 are connected, and the third interface 21 and the fourth interface 22 are connected.

[0036] As an implementation mode of this embodiment, the fourth interface 22 of the four-way valve 17 and the other end of the first media channel are connected through a first pipeline 23, and a first one-way valve 24 is provided on the first pipeline 23, and the first one-way valve 24 is used to allow the medium of the fourth interface 22 to flow to the other end of the first media channel.

[0037] As an implementation mode of this embodiment, one end of the first heat exchanger 13 is connected to the first pipeline 23 through the second pipeline 25, and the second pipeline 25 is located on the inflow side of the first one-way valve 24; the other end of the first heat exchanger 13 is connected to the first pipeline 23 through the third pipeline 36, and the third pipeline 36 is located on the outflow side of the first one-way valve 24.

[0038] As an implementation of this embodiment, the valve is a second one-way valve 26 , and the valve is arranged on the second pipeline 25 . The second one-way valve 26 is used to allow the medium in the first heat exchanger 13 to flow to the fourth interface 22 of the four-way valve 17 .

[0039] In the defrosting mode, the medium in the primary temperature control system 11 is facilitated to flow into the first heat exchanger 13 , and in the heating mode, the medium in the primary temperature control system 11 is prevented from flowing into the first heat exchanger 13 .

[0040] As an implementation method of this embodiment, an economizer 27 is provided between the third heat exchanger 18 and the intermediate heat exchanger 15, and a third medium channel and a fourth medium channel are provided on the economizer 27, wherein the economizer 27 is an existing device, and the internal structure of the economizer 27 is not shown in the attached drawings. The other end of the third heat exchanger 18 is connected to one end of the fourth medium channel through the fourth pipeline 28, and the other end of the fourth medium channel is connected to one end of the first medium channel through the fifth pipeline 29; a branch pipe 30 connected to the third medium channel is installed on the fourth pipeline 28, and the end of the third medium channel away from the branch pipe 30 is connected to the air supply port of the first compressor 16 through the sixth pipeline 31.

[0041] The technical effect of this solution is that when the air intake of the first-stage compressor 16 is insufficient, the gas in the air replenishing port can be replenished into the compressor in time, thereby ensuring the stable operation of the first-stage compressor 16.

[0042] Furthermore, a first electronic expansion valve 32 is installed on the fourth pipeline 28 , and a second electronic expansion valve 33 is installed on the branch pipe 30 .

[0043] As an implementation of this embodiment, the secondary temperature control system 12 includes a secondary compressor 34, the exhaust port of the secondary compressor 34 is connected to one end of the second heat exchanger 14, the other end of the second heat exchanger 14 is connected to one end of the second medium channel, and the other end of the second medium channel is connected to the air inlet of the secondary compressor 34. Furthermore, a third electronic expansion valve 35 is provided between the other end of the second heat exchanger 14 and one end of the second medium channel.

[0044] Furthermore, a first gas-liquid separator 37 is provided at the air inlet of the first-stage compressor 16. A first liquid storage tank 38 is provided on the fifth pipeline 29.

[0045] Furthermore, a second gas-liquid separator 39 is provided at the air inlet of the secondary compressor 34 .

[0046] like Figure 1 As shown, the working principle in the heating mode is as follows: the high-temperature and high-pressure medium discharged from the first-stage compressor 16 flows into the first interface 19, and then flows into the first medium channel of the intermediate heat exchanger 15 through the fourth interface 22 and the first pipeline 23, and then the medium flows into the fourth medium channel in the economizer 27 through the fifth pipeline 29, and then the medium flows into the third heat exchanger 18 through the fourth pipeline 28 and the first electronic expansion valve 32, and finally the medium in the third heat exchanger 18 flows into the air inlet of the first-stage compressor 16 through the second interface 20 and the third interface 21.

[0047] The high-temperature and high-pressure medium discharged from the secondary compressor 34 flows into the second heat exchanger 14 and is used to heat the water channel. The medium flowing out of the second heat exchanger 14 flows into the second medium channel of the intermediate heat exchanger 15 through the third electronic expansion valve 35, wherein the first medium channel and the second medium channel exchange heat to heat the medium in the second medium channel.

[0048] The working principle in defrost mode is as follows:

[0049] like Figure 2 As shown, in order to ensure the defrosting effect of the third heat exchanger 18 under low temperature environment, the high-temperature and high-pressure medium discharged from the first-stage compressor 16 flows into the third heat exchanger 18 through the first interface 19 and the second interface 20 to defrost the third heat exchanger 18, and then the medium flows into the first medium channel of the intermediate heat exchanger 15 through the fourth pipeline 28, the fourth medium channel in the economizer 27, and the fifth pipeline 29, and then the medium flows into the first heat exchanger 13 through the third pipeline 36 and heats the water flow channel, and the heated medium flows into the air inlet of the first-stage compressor 16 through the second pipeline 25, the second one-way valve 26, the fourth interface 22, and the third interface 21.

[0050] The high-temperature and high-pressure medium discharged from the secondary compressor 34 flows into the second heat exchanger 14 and is used to heat the water channel. The medium flowing out of the second heat exchanger 14 flows into the second medium channel of the intermediate heat exchanger 15 through the third electronic expansion valve 35. The first medium channel and the second medium channel do not exchange heat, so that the water temperature in the water channel is not too high, and the water channel can heat the medium in the primary temperature control system 11, which can effectively defrost the third heat exchanger 18 while ensuring the stable operation of the primary compressor 16.

[0051] For ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the utility model, which all fall within the protection scope of the utility model.

Claims

1. A cascade temperature control system, characterized in that: The invention comprises a primary temperature control system (11), a secondary temperature control system (12), a first heat exchanger (13), a second heat exchanger (14) and an intermediate heat exchanger (15); the medium channels of the first heat exchanger (13) and the second heat exchanger (14) are arranged in isolation, and the water channels of the first heat exchanger (13) and the second heat exchanger (14) are arranged in parallel; the primary temperature control system (11) and the secondary temperature control system (12) perform heat exchange via the intermediate heat exchanger (15); The medium channel of the first heat exchanger (13) is connected to the medium channel of the primary temperature control system (11) through a valve; The medium channel of the second heat exchanger (14) is connected to the medium channel of the secondary temperature control system (12).

2. The cascade temperature control system according to claim 1, characterized in that: The intermediate heat exchanger (15) has a first medium channel and a second medium channel, the first medium channel is connected to the primary temperature control system (11), and the second medium channel is connected to the secondary temperature control system (12).

3. The cascade temperature control system according to claim 2, characterized in that: The primary temperature control system (11) comprises: a primary compressor (16), a four-way valve (17) and a third heat exchanger (18); the exhaust port of the primary compressor (16) is connected to a first interface (19) of the four-way valve (17); the second interface (20) of the four-way valve (17) is connected to one end of the third heat exchanger (18); the other end of the third heat exchanger (18) is connected to one end of the first medium channel; the fourth interface (22) of the four-way valve (17) is connected to the other end of the first medium channel via a first one-way valve (24); and the third interface (21) of the four-way valve (17) is connected to an air inlet of the primary compressor (16).

4. The cascade temperature control system according to claim 3, characterized in that: The fourth interface (22) of the four-way valve (17) and the other end of the first medium channel are connected via a first pipeline (23), and the first one-way valve (24) is provided on the first pipeline (23), and the first one-way valve (24) is used to allow the medium of the fourth interface (22) to flow to the other end of the first medium channel.

5. The cascade temperature control system according to claim 4, characterized in that: One end of the first heat exchanger (13) is connected to the first pipeline (23) through a second pipeline (25), and the second pipeline (25) is located on the inflow side of the first one-way valve (24); the other end of the first heat exchanger (13) is connected to the first pipeline (23) through a third pipeline (36), and the third pipeline (36) is located on the outflow side of the first one-way valve (24).

6. The cascade temperature control system according to claim 5, characterized in that: The valve is a second one-way valve (26), and the valve is arranged on the second pipeline (25). The second one-way valve (26) is used to allow the medium in the first heat exchanger (13) to flow to the fourth interface (22) of the four-way valve (17).

7. The cascade temperature control system according to claim 5, characterized in that: An economizer (27) is provided between the third heat exchanger (18) and the intermediate heat exchanger (15); a third medium channel and a fourth medium channel are provided on the economizer (27); the other end of the third heat exchanger (18) is connected to one end of the fourth medium channel via a fourth pipeline (28); and the other end of the fourth medium channel is connected to one end of the first medium channel via a fifth pipeline (29); The fourth pipeline (28) is provided with a branch pipe (30) connected to the third medium channel, and an end of the third medium channel away from the branch pipe (30) is connected to the air supply port of the first-stage compressor (16) through a sixth pipeline (31).

8. The cascade temperature control system according to claim 7, characterized in that: A first electronic expansion valve (32) is installed on the fourth pipeline (28); and a second electronic expansion valve (33) is installed on the branch pipe (30).

9. The cascade temperature control system according to claim 2, characterized in that: The secondary temperature control system (12) comprises a secondary compressor (34), an exhaust port of the secondary compressor (34) being connected to one end of the second heat exchanger (14), the other end of the second heat exchanger (14) being connected to one end of the second medium channel, and the other end of the second medium channel being connected to an air inlet of the secondary compressor (34).

10. The cascade temperature control system according to claim 9, characterized in that: A third electronic expansion valve (35) is provided between the other end of the second heat exchanger (14) and one end of the second medium channel.

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