High-temperature efficient two-stage heat pump system

Abstract

The utility model discloses a high-temperature and high-efficiency two-stage heat pump system. The high-temperature and high-efficiency two-stage heat pump system comprises a first-stage heat pump, a second-stage heat pump and a buffer water tank energy storage and release system, the first-stage heat pump comprises a first-stage compressor, a first channel of the multi-channel heat exchanger and a first-stage evaporator, and a first circulation loop is formed. The buffer water tank energy storage and release system comprises a buffer water tank, an internal circulating pump and a second channel of the multi-channel heat exchanger to form a second circulating loop; the second-stage heat pump comprises a second-stage condenser, and the third channel of the multi-channel heat exchanger and the second-stage condenser form a third circulation loop; the second-stage condenser is connected with an energy supply water outlet pipe and an energy supply water return pipe to form a fourth circulation loop; the buffer water tank is sequentially connected with a second one-way valve and an energy supply water outlet pipe, and an eighth pipeline is sequentially connected with a second valve, a second channel of the multi-channel heat exchanger and an inlet of the buffer water tank to form a fifth circulation loop. The utility model has the advantage of high-temperature, high-efficiency and energy-saving operation in a severe cold environment.

Description

Technical Field

[0001] The utility model relates to the field of heat pump heating, in particular to a high-temperature and high-efficiency two-stage heat pump system. Background Art

[0002] The two-stage compression air source heat pump products on the market currently have the following main problems: First, simple cascade two-stage heat pumps are difficult to match, and cannot meet the stable supply between the first-stage heat supply and the heat required by the second-stage heat pump under different environmental conditions, resulting in unstable equipment operation, and the simple cascade two-stage heat pump cannot achieve the refrigeration function; second, the water-coupled unit requires two heat exchanges, which reduces the operating efficiency of the unit. Utility Model Content

[0003] The purpose of the embodiments of the utility model is to provide a high-temperature and high-efficiency two-stage heat pump system with stable operation and high efficiency in view of the defects of the above-mentioned prior art.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] A high-temperature and high-efficiency two-stage heat pump system, comprising: a primary heat pump, a secondary heat pump and a buffer water tank energy storage and release system;

[0006] The primary heat pump comprises a primary compressor, the outlet of the primary compressor is connected to a first pipeline through a primary four-way valve, the first pipeline is connected to a first channel inlet of a multi-channel heat exchanger, the first channel outlet of the multi-channel heat exchanger is sequentially connected to a second pipeline, a primary throttling device and a primary evaporator, the primary evaporator is connected to the inlet of the primary compressor through a primary four-way valve, so as to form a first circulation loop;

[0007] The buffer water tank energy storage and release system comprises a buffer water tank, the inlet of the buffer water tank is connected to the second channel outlet of the multi-channel heat exchanger through a third pipeline, and the outlet of the buffer water tank is sequentially connected to a fourth pipeline, an internal circulation pump, a first one-way valve, a fifth pipeline and the second channel inlet of the multi-channel heat exchanger to form a second circulation loop;

[0008] The secondary heat pump comprises a secondary condenser, wherein the first flow channel outlet of the secondary condenser is sequentially connected to the secondary throttling device, the sixth pipeline, the third channel of the multi-channel heat exchanger, the seventh pipeline, the secondary compressor and the first flow channel inlet of the secondary condenser to form a third circulation loop;

[0009] The outlet of the second flow channel of the secondary condenser is connected to the energy supply water outlet pipe, and the inlet of the second flow channel of the secondary condenser is connected to the energy supply return pipe through the first valve, the eighth pipeline and the energy supply circulation pump in sequence to form a fourth circulation loop;

[0010] The outlet of the buffer water tank is connected to the energy supply outlet pipe through a second one-way valve, and the eighth pipeline is sequentially connected to the second valve, the ninth pipeline, the second channel of the multi-channel heat exchanger and the inlet of the buffer water tank to form a fifth circulation loop.

[0011] The ninth pipeline is connected to the fifth pipeline, and the energy supply water outlet pipe is connected to the fourth pipeline through the second one-way valve.

[0012] The multi-channel heat exchanger has three channels, namely the first channel, the second channel and the third channel. The three channels form a group of channels. The first channel is located between the second channel and the third channel. The first channel is a primary heat pump refrigerant heat exchange channel, the second channel is a water channel heat exchange channel, and the third channel is a secondary heat pump refrigerant heat exchange channel.

[0013] There are more than two channels in a group, and each channel in a group is arranged adjacent to each other, and is arranged in the order of the third channel, the first channel and the second channel.

[0014] The inlet of each first channel is connected to the first pipeline through a corresponding inlet pipe, and the outlet of each first channel is connected to the second pipeline through a corresponding outlet pipe;

[0015] The inlet of each second channel is connected to the fifth pipeline through a corresponding inlet pipe, and the outlet of each second channel is connected to the third pipeline through a corresponding outlet pipe;

[0016] The inlet of each third channel is connected to the sixth channel through a corresponding inlet pipe, and the outlet of each third channel is connected to the seventh channel through a corresponding outlet pipe.

[0017] In the group of channels, the medium flows in adjacent channels in opposite directions.

[0018] An electric heater is arranged in the buffer water tank.

[0019] The first valve and the second valve are both electric valves.

[0020] The utility model also provides a control method for the high-temperature and high-efficiency two-stage heat pump system, comprising the following steps:

[0021] Single-stage heating mode: open the second valve and close the first valve; start the energy circulation pump and the first-stage heat pump, stop the internal circulation pump and the second-stage heat pump, and the first circulation loop and the fifth circulation loop work; at this time, the first-stage heat pump starts heating and supplies heat to the outside through the multi-channel heat exchanger;

[0022] Two-stage heating mode: open the second valve and close the first valve; start the energy circulation pump, the primary heat pump and the secondary heat pump; the secondary heat pump absorbs the heat provided by the primary heat pump through the third channel of the multi-channel heat exchanger and supplies heat to the outside through the secondary condenser of the secondary heat pump;

[0023] In the two-stage heating mode, the buffer water tank energy storage system automatically operates according to the heating capacity of the first-stage heat pump and the heat required by the second-stage heat pump:

[0024] When the heating capacity of the primary heat pump is greater than the heat required by the secondary heat pump, the internal circulation pump is started, and part of the heat is absorbed through the second channel of the multi-channel heat exchanger and stored in the buffer water tank to avoid the primary heat pump providing too much heat to impact the secondary heat pump and the frequent start and stop of the primary heat pump;

[0025] When the heating capacity of the primary heat pump is equal to the heat required by the secondary heat pump, the internal circulation pump is stopped, the buffer water tank no longer absorbs heat, and the heating capacity of the primary heat pump is fully supplied to the secondary heat pump;

[0026] When the heating capacity of the primary heat pump cannot meet the heat required by the secondary heat pump, the internal circulation pump is started, and the buffer water tank releases the stored heat to heat the secondary heat pump together with the primary heat pump to ensure that the secondary heat pump obtains sufficient heat to work normally;

[0027] When the heating capacity of the first-stage heat pump is insufficient, the electric heater in the buffer water tank is started to supplement some heat to ensure the heat required for the normal operation of the second-stage heat pump;

[0028] Cooling mode: open the second valve and close the first valve; start the energy circulation pump and the first-stage heat pump, stop the internal circulation pump and the second-stage heat pump; the first circulation loop and the fifth circulation loop work; at this time, the first-stage heat pump starts the cooling work and supplies cold air to the outside through the multi-channel heat exchanger;

[0029] Defrost mode: start the internal circulation pump and the primary heat pump, and the heat stored in the buffer water tank is provided to the primary heat pump as a defrosting heat source through the second channel of the multi-channel heat exchanger in the second circulation loop; when the buffer water tank has insufficient heat, start the electric heater in the buffer water tank to supplement part of the heat to ensure the heat required for defrosting of the primary heat pump. In this mode, the power supply circulation pump and the secondary heat pump are stopped, and external heating is stopped.

[0030] Furthermore, a temperature sensor is provided on the multi-channel heat exchanger to detect the temperature in the multi-channel heat exchanger; the detected temperature in the multi-channel heat exchanger is compared with the first set value, the second set value and the third set value, and the comparison result is as follows:

[0031] When it is detected that the temperature of the multi-channel heat exchanger exceeds the first set value, it is determined that the heating capacity of the primary heat pump is greater than the heat required by the secondary heat pump;

[0032] When it is detected that the temperature of the multi-channel heat exchanger is between the first set value and the second set value, it is determined that the heating capacity of the primary heat pump is equivalent to the heat required by the secondary heat pump;

[0033] When it is detected that the temperature of the multi-channel heat exchanger is less than the second set value, it is determined that the heating capacity of the primary heat pump cannot meet the heat required by the secondary heat pump;

[0034] When it is detected that the temperature of the multi-channel heat exchanger is less than the third set value, it is determined that the heating capacity of the primary heat pump is insufficient.

[0035] The first setting value is 43-47°C, the second setting value is 39-42°C, and the third setting value is 33-38°C.

[0036] The beneficial effects brought by the technical solution provided by the embodiment of the utility model are:

[0037] The system of the utility model adopts two-stage compression technology and a supporting buffer water tank energy storage system, which can realize efficient operation of the system and high-temperature heating under severe cold environmental conditions. The system defrosts using the heat of the buffer water tank, without extracting the heat from the terminal, thus improving the heating comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of a high-temperature and high-efficiency two-stage heat pump system provided in an embodiment of the utility model.

[0039] In the figure:

[0040] 1-primary heat pump; 2-secondary heat pump; 3-buffer water tank energy storage system; 4-primary compressor; 5-primary four-way valve; 6-first pipeline; 7-multi-channel heat exchanger; 8-second pipeline; 9-primary throttling device; 10-primary evaporator; 11-buffer water tank; 12-third pipeline; 13-fourth pipeline; 14-internal circulation pump; 15-first one-way valve; 16-fifth pipeline; 17-secondary condenser; 18-secondary throttling device; 19-sixth pipeline; 20-seventh pipeline; 21-secondary compressor; 22-energy supply water outlet pipe; 23-first valve; 24-eighth pipeline; 25-energy supply circulation pump; 26-energy supply return pipe; 27-second one-way valve; 28-second valve; 29-ninth pipeline; 30-electric heater; 31-first channel; 32-second channel; 33-third channel. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clear, the implementation mode of the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] See also Figure 1, a high-temperature and high-efficiency two-stage heat pump system, comprising: a primary heat pump 1, a buffer water tank energy storage system 2 and a secondary heat pump 3;

[0043] The primary heat pump 1 comprises a primary compressor 4, the outlet of the primary compressor 4 is connected to a first pipeline 6 through a primary four-way valve 5, the first pipeline 6 is connected to a first channel inlet of a multi-channel heat exchanger 7, the first channel outlet of the multi-channel heat exchanger 7 is sequentially connected to a second pipeline 8, a primary throttling device 9 and a primary evaporator 10, the primary evaporator 10 is connected to the inlet of the primary compressor 4 through the primary four-way valve 5, forming a first circulation loop, which is a circulation loop of a primary heat pump refrigerant system;

[0044] The buffer water tank energy storage and release system 2 comprises a buffer water tank 11, the inlet of the buffer water tank 11 is connected to the second channel outlet of the multi-channel heat exchanger 7 through a third pipe 12, and the outlet of the buffer water tank 11 is sequentially connected to a fourth pipe 13, an internal circulation pump 14, a first one-way valve 15, a fifth pipe 16 and the second channel inlet of the multi-channel heat exchanger 7 to form a second circulation loop; it is a two-stage operation buffer water tank heat charging and discharging loop and a primary heat pump defrosting operation heating loop of the system;

[0045] The secondary heat pump 3 includes a secondary condenser 17, the first flow channel outlet of the secondary condenser 17 is sequentially connected to the secondary throttling device 18, the sixth pipeline 19, the third channel of the multi-channel heat exchanger 7, the seventh pipeline 20, the secondary compressor 21 and the first flow channel inlet of the secondary condenser 17, forming a third circulation loop, which is a secondary heat pump refrigerant system circulation loop;

[0046] The outlet of the second flow channel of the secondary condenser 17 is connected to the energy supply outlet pipe 22, and the inlet of the second flow channel of the secondary condenser 17 is connected to the energy supply return pipe 26 through the first valve 23, the eighth pipeline 24 and the energy supply circulation pump 25 in sequence, forming a fourth circulation loop, which is a dual-stage operation heating loop of the system;

[0047] The outlet of the buffer water tank 11 is connected to the energy water outlet pipe 22 through the second one-way valve 27. The eighth pipeline 24 is connected to the second valve 28, the ninth pipeline 29, the second channel of the multi-channel heat exchanger 7 and the inlet of the buffer water tank 11 in sequence to form a fifth circulation loop, which is a single-stage heating or cooling loop for the system.

[0048] The utility model adopts a dual compressor system with a buffer water tank energy storage system, which can automatically operate in single or double stages, and can achieve efficient operation of the system and high-temperature heating under severe cold environmental conditions.

[0049] In order to save pipeline connections, the ninth pipeline 29 is connected to the fifth pipeline 16 , and the energy water outlet pipe 22 is connected to the fourth pipeline 13 via the second one-way valve 27 .

[0050] Furthermore, the multi-channel heat exchanger 7 has three channels, namely the first channel 31, the second channel 32 and the third channel 33. The three channels form a group of channels. The first channel 31 is located between the second channel 32 and the third channel 33. The first channel 31 is a primary heat pump refrigerant heat exchange channel, which is a fluorine path channel. The second channel 32 contains water and is a water heat exchange channel. The third channel 33 is a secondary heat pump refrigerant heat exchange channel, which is a fluorine path channel.

[0051] The multi-channel heat exchanger of the utility model preferably adopts a three-channel heat exchanger, and heat exchange can be performed between any two channels of the three channels, or heat exchange can be performed between the three channels at the same time.

[0052] Preferably, there are more than two channels in a group, and each group of channels is arranged adjacent to each other, and is arranged in the order of the third channel 33, the first channel 31 and the second channel 32, that is, a plurality of channels are arranged, and each channel is arranged from left to right in the order of the third channel 33, the first channel 31 and the second channel 32, such as Figure 1 Arrangement shown.

[0053] Multiple channels are set up to ensure that the multi-channel heat exchanger has sufficient heat exchange capacity.

[0054] Further, the inlet of each first channel 31 is connected to the first pipeline 6 through a corresponding inlet pipe, and the outlet of each first channel 31 is connected to the second pipeline 8 through a corresponding outlet pipe;

[0055] The inlet of each second channel 32 is connected to the fifth pipeline 16 through a corresponding inlet pipe, and the outlet of each second channel 32 is connected to the third pipeline 12 through a corresponding outlet pipe;

[0056] The inlet of each third channel 33 is connected to the sixth pipeline 19 through a corresponding inlet pipe, and the outlet of each third channel 33 is connected to the seventh pipeline 20 through a corresponding outlet pipe.

[0057] In order to increase the heat exchange efficiency, in the group of channels, the medium flows in adjacent channels in opposite directions.

[0058] Preferably, an electric heater 30 is provided in the buffer water tank 11 .

[0059] Preferably, in order to realize automatic control, the first valve 23 and the second valve 28 are both electric valves.

[0060] In the two-stage heat pump system of the utility model, the two-stage heat pumps are independent heat pumps, which can be connected in series to form a two-stage mode for operation, or can be operated in a single-stage mode in which the first-stage heat pump is in operation and the second-stage heat pump is stopped. When the single-stage mode is in operation, external heating or cooling can be realized, and when the two-stage mode is in operation, external heating can be realized. When the system is in the two-stage mode, the secondary heat pump directly absorbs the heat provided by the primary heat pump through a multi-channel heat exchanger, and provides high-temperature heat to the outside, so that efficient operation can be achieved. When the system is in the two-stage mode, the buffer water tank energy storage and release system can store or release heat when the heating capacity of the primary heat pump does not match the heat required by the secondary heat pump, so as to ensure the stable operation of the heat pump system.

[0061] The control operation mode of the utility model high temperature and high efficiency two-stage heat pump system is as follows:

[0062] Single-stage heating mode: open the second valve 28 and close the first valve 23; start the energy supply circulation pump 25 and the primary heat pump 1, stop the operation of the internal circulation pump 14 and the secondary heat pump 3, and the first circulation loop and the fifth circulation loop work; at this time, the primary heat pump 1 starts heating and supplies heat to the outside through the first channel 31 of the multi-channel heat exchanger 7;

[0063] Two-stage heating mode: open the second valve 28, close the first valve 23; start the energy supply circulation pump 25, the primary heat pump 1 and the secondary heat pump 3; the secondary heat pump 3 absorbs the heat provided by the primary heat pump 1 through the third channel 33 of the multi-channel heat exchanger 7 and supplies heat to the outside through the secondary condenser 17 of the secondary heat pump 3; in this operation mode, the buffer water tank storage and release system 2 automatically operates according to the heating capacity of the primary heat pump 1 and the heat required by the secondary heat pump 3:

[0064] When the heating capacity of the primary heat pump 1 is greater than the heat required by the secondary heat pump 3, that is, when it is detected that the temperature of the multi-channel heat exchanger 7 exceeds the first set value, which is 43-47°C, preferably 45°C, the internal circulation pump 14 is started, and part of the heat is absorbed through the second channel 32 of the multi-channel heat exchanger 7 and stored in the buffer water tank 11, so as to avoid the primary heat pump 1 providing too much heat to impact the secondary heat pump 3 and the frequent start and stop of the primary heat pump 1;

[0065] When the heating capacity of the primary heat pump 1 is equal to the heat demand of the secondary heat pump 2, that is, when it is detected that the temperature of the multi-channel heat exchanger 7 is between the first set value and the second set value, preferably 40-45°C, the internal circulation pump 14 is stopped, the buffer water tank 11 no longer absorbs heat, and the heating capacity of the primary heat pump 1 is fully supplied to the secondary heat pump 3;

[0066] When the heating capacity of the primary heat pump 1 cannot meet the heat required by the secondary heat pump 3, that is, when it is detected that the temperature of the multi-channel heat exchanger 7 is lower than the second set value, the second set value is 39-42°C, and the second set value is preferably 40°C, the internal circulation pump 14 is started, and the buffer water tank 11 releases the stored heat to heat the secondary heat pump 3 together with the primary heat pump 1, so as to ensure that the secondary heat pump 3 obtains sufficient heat to work normally;

[0067] When the heating capacity of the primary heat pump 1 is seriously insufficient under extreme environmental conditions, that is, when it is detected that the temperature of the multi-channel heat exchanger 7 is lower than the third set value, the third set value is 33-38°C, and the third set value is preferably 35°C, the electric heater 30 in the buffer water tank 11 is started to supplement part of the heat to ensure the heat required for the normal operation of the secondary heat pump 3;

[0068] The set value of the utility model can be adjusted according to actual needs, and the operation of the system can be controlled according to the adjusted temperature value.

[0069] Cooling mode: open the second valve 28, close the four-one valve 23; start the energy supply circulation pump 25 and the primary heat pump 1, stop the operation of the internal circulation pump 14 and the secondary heat pump 3, the first circulation loop and the fifth circulation loop are working, at this time the primary heat pump 1 starts the cooling work and supplies cold air to the outside through the multi-channel heat exchanger 7;

[0070] Defrosting mode: start the internal circulation pump 14 and the primary heat pump 1, and the heat stored in the buffer water tank 11 is provided to the primary heat pump 1 as a defrosting heat source through the second channel 32 of the multi-channel heat exchanger 7 in the second circulation loop. When the buffer water tank 11 is insufficient in heat, start the electric heater 30 in the buffer water tank 11 to supplement part of the heat to ensure the heat required for defrosting of the primary heat pump 1. In this mode, the operation of the power supply circulation pump 25 and the secondary heat pump 3 is stopped, and the system stops supplying heat to the outside.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-temperature and high-efficiency two-stage heat pump system, characterized in that: include: Primary heat pump, secondary heat pump and buffer water tank energy storage and release system; The primary heat pump comprises a primary compressor, the outlet of the primary compressor is connected to a first pipeline through a primary four-way valve, the first pipeline is connected to a first channel inlet of a multi-channel heat exchanger, the first channel outlet of the multi-channel heat exchanger is sequentially connected to a second pipeline, a primary throttling device and a primary evaporator, the primary evaporator is connected to the inlet of the primary compressor through a primary four-way valve, so as to form a first circulation loop; The buffer water tank energy storage and release system comprises a buffer water tank, the inlet of the buffer water tank is connected to the second channel outlet of the multi-channel heat exchanger through a third pipeline, and the outlet of the buffer water tank is sequentially connected to a fourth pipeline, an internal circulation pump, a first one-way valve, a fifth pipeline and the second channel inlet of the multi-channel heat exchanger to form a second circulation loop; The secondary heat pump comprises a secondary condenser, wherein the first flow channel outlet of the secondary condenser is sequentially connected to the secondary throttling device, the sixth pipeline, the third channel of the multi-channel heat exchanger, the seventh pipeline, the secondary compressor and the first flow channel inlet of the secondary condenser to form a third circulation loop; The outlet of the second flow channel of the secondary condenser is connected to the energy supply water outlet pipe, and the inlet of the second flow channel of the secondary condenser is connected to the energy supply return pipe through the first valve, the eighth pipeline and the energy supply circulation pump in sequence to form a fourth circulation loop; The outlet of the buffer water tank is connected to the energy supply outlet pipe through a second one-way valve, and the eighth pipeline is sequentially connected to the second valve, the ninth pipeline, the second channel of the multi-channel heat exchanger and the inlet of the buffer water tank to form a fifth circulation loop.

2. The high-temperature and high-efficiency two-stage heat pump system according to claim 1, characterized in that: The ninth pipeline is connected to the fifth pipeline, and the energy supply water outlet pipe is connected to the fourth pipeline through the second one-way valve.

3. The high-temperature and high-efficiency two-stage heat pump system according to claim 2, characterized in that: The multi-channel heat exchanger has three channels, namely the first channel, the second channel and the third channel. The three channels form a group of channels. The first channel is located between the second channel and the third channel. The first channel is a primary heat pump refrigerant heat exchange channel, the second channel is a water channel heat exchange channel, and the third channel is a secondary heat pump refrigerant heat exchange channel.

4. The high-temperature and high-efficiency two-stage heat pump system according to claim 3, characterized in that: There are more than two channels in a group, and each channel in a group is arranged adjacent to each other, and is arranged in the order of the third channel, the first channel and the second channel.

5. The high-temperature and high-efficiency two-stage heat pump system according to claim 4, characterized in that: The inlet of each first channel is connected to the first pipeline through a corresponding inlet pipe, and the outlet of each first channel is connected to the second pipeline through a corresponding outlet pipe; The inlet of each second channel is connected to the fifth pipeline through a corresponding inlet pipe, and the outlet of each second channel is connected to the third pipeline through a corresponding outlet pipe; The inlet of each third channel is connected to the sixth pipeline through a corresponding inlet pipe, and the outlet of each third channel is connected to the seventh pipeline through a corresponding outlet pipe.

6. The high-temperature and high-efficiency two-stage heat pump system according to claim 5, characterized in that: In the group of channels, the medium flows in adjacent channels in opposite directions.

7. The high-temperature and high-efficiency two-stage heat pump system according to any one of claims 1 to 6, characterized in that: An electric heater is arranged in the buffer water tank.

8. The high-temperature and high-efficiency two-stage heat pump system according to claim 7, characterized in that: The first valve and the second valve are both electric valves.

Images