Carbon dioxide heat pump water heater

Abstract

The utility model discloses a carbon dioxide heat pump water heater, and relates to the field of heat pump water heaters. Comprising a first compressor, an oil separator, a first heat exchanger, a second heat exchanger, a first valve, a third heat exchanger, a second valve, a fourth heat exchanger, a third valve, a fourth valve, a fifth valve, a liquid storage device, a fifth heat exchanger, a gas-liquid separator, a capillary tube, a sixth valve, a second compressor, a seventh valve and an eighth valve which are sequentially connected through copper pipes. The mode of combining the flash tank and the economizer is adopted, the refrigerant temperature of a liquid pipe is further reduced, the temperature in front of a second-stage throttling valve is reduced, throttling loss is reduced, the effect of reducing the pressure ratio of each stage of the system and then reducing the power consumption of the system can be achieved, the exhaust temperature of the compressor can be reduced by adopting middle air supplement, and the operation conditions of the compressor are improved. In addition, defrosting is carried out in the mode that a hot gas bypass and a compressor are combined, and water temperature fluctuation and system instability caused by four-way valve switching defrosting are avoided.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of heat pump water heater, especially relates to a carbon dioxide heat pump water heater. BACKGROUND

[0002] Carbon dioxide is a natural working medium, and its global warming potential GWP value is only 1, which is a good heat transfer performance refrigerant. However, the high and low pressure difference of the carbon dioxide heat pump unit system is large, generally belongs to transcritical cycle, although the traditional fixed structure ejector throttling can recover part of the expansion work, but it cannot be self-adaptive to adjust to adapt to the condition of wide working condition range. Furthermore, the general heat pump unit will use flash tank or economizer to supplement air and increase enthalpy to improve the capacity and performance of the unit, but the combination of the two is less used. In addition, carbon dioxide is used for heat pump water heater due to the large pressure difference of the system, cannot use the four-way valve switching form for defrosting, otherwise it will easily cause damage to the system pipeline components and large noise, which is not conducive to the safe operation of the whole machine. SUMMARY

[0003] In view of the problems mentioned in the background art, the purpose of the utility model is to provide a carbon dioxide heat pump water heater to solve the problems mentioned in the background art.

[0004] The above technical purpose of the utility model is realized by the following technical scheme:

[0005] A carbon dioxide heat pump water heater, comprising: a first compressor, an oil separator, a first heat exchanger, a second heat exchanger, a first valve, a third heat exchanger, a second valve, a fourth heat exchanger, a third valve, a fourth valve, a fifth valve, a liquid accumulator, a fifth heat exchanger, a gas-liquid separator, a capillary tube, a sixth valve, a second compressor, a seventh valve and an eighth valve are connected in sequence by copper pipes, the first compressor exhaust port is connected and installed with the oil separator inlet, the oil separator bottom oil return pipe is connected and installed with the capillary tube, the capillary tube outlet is connected and installed with the gas-liquid separator inlet, the oil separator top outlet is connected and installed with the first heat exchanger refrigerant inlet, the first heat exchanger refrigerant outlet is connected and installed with the second heat exchanger main loop inlet, the second heat exchanger refrigerant main loop outlet is connected and installed with the first valve, the first valve outlet is connected and installed with the third heat exchanger top inlet, the third heat exchanger bottom outlet is connected and installed with the fourth heat exchanger refrigerant main loop inlet, the fourth heat exchanger main loop refrigerant outlet is connected and installed with the fifth heat exchanger refrigerant inlet, the fifth heat exchanger refrigerant outlet is connected and installed with the second heat exchanger auxiliary loop refrigerant inlet, and the second heat exchanger auxiliary loop refrigerant outlet is connected and installed with the gas-liquid separator refrigerant inlet.

[0006] As a preferred technical scheme, a bypass pipeline is arranged at the middle of the oil separator and the first heat exchanger, and the bypass pipeline is connected with the inlet of the eighth valve.

[0007] As a preferred technical scheme, the gas pipe outlet of the third heat exchanger is connected with the second valve and the second compressor, and the gas outlet of the second compressor is connected with the refrigerant inlet of the fifth heat exchanger.

[0008] As a preferred technical scheme, the liquid pipe outlet at the bottom of the third heat exchanger is connected with a bypass pipeline and the third valve at the middle of the refrigerant liquid pipe inlet of the main pipeline of the fourth heat exchanger.

[0009] As a preferred technical scheme, the third heat exchanger is connected with a gas pipe bypass pipeline and the inlet of the sixth valve at the middle of the second valve, and the outlet of the sixth valve is connected with the auxiliary gas pipe outlet of the fourth heat exchanger.

[0010] As a preferred technical scheme, the fourth valve is connected with a refrigerant pipeline bypassing the pipeline at the middle of the fifth heat exchanger and the fifth valve.

[0011] In summary, the utility model mainly has the following beneficial effects:

[0012] The technical scheme adopts the form of double electronic expansion valves and a heat exchanger, the heat exchanger is used for reducing the temperature before the primary throttle valve and ensuring the suction superheat of the compressor to avoid liquid suction, the primary throttle valve is used for adjusting the discharge pressure of the compressor and reducing the throttling loss, and the secondary throttle valve is used for throttling control of the circulation amount of refrigerant; the form of the flash tank and the economizer is combined to further reduce the temperature of liquid pipe refrigerant, reduce the temperature before the secondary throttle valve and reduce the throttling loss, can reduce the pressure ratio of each stage of the system and reduce the system power consumption, the intermediate air supplement can reduce the discharge temperature of the compressor and improve the operation condition of the compressor. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is the system flow chart of the utility model;

[0014] Figure 2 is the heating mode flow chart of the utility model;

[0015] Figure 3 is the defrosting mode 1 flow chart of the utility model;

[0016] Figure 4 is the defrosting mode 2 flow chart of the utility model.

[0017] Reference numerals: 1, first compressor; 2, oil separator; 3, first heat exchanger; 4, second heat exchanger; 5, first valve; 6, third heat exchanger; 7, second valve; 8, fourth heat exchanger; 9, third valve; 10, fourth valve; 11, fifth valve; 12, liquid accumulator; 13, fifth heat exchanger; 14, gas-liquid separator; 15, capillary tube; 16, sixth valve; 17, second compressor; 18, seventh valve; 19, eighth valve. DETAILED DESCRIPTION

[0018] Reference Figures 1 to 4The carbon dioxide heat pump water heater comprises a first compressor 1, an oil separator 2, a first heat exchanger 3, a second heat exchanger 4, a first valve 5, a third heat exchanger 6, a second valve 7, a fourth heat exchanger 8, a third valve 9, a fourth valve 10, a fifth valve 11, a liquid accumulator 12, a fifth heat exchanger 13, a gas-liquid separator 14, a capillary tube 15, a sixth valve 16, a second compressor 17, a seventh valve 18 and an eighth valve 19 which are sequentially connected by copper pipes, the exhaust port of the first compressor 1 is connected and installed with the inlet of the oil separator 2, the bottom oil return pipe of the oil separator 2 is connected and installed with the capillary tube 15, the outlet of the capillary tube 15 is connected and installed with the inlet of the gas-liquid separator 14, the top outlet of the oil separator 2 is connected and installed with the refrigerant inlet of the first heat exchanger 3, the refrigerant outlet of the first heat exchanger 3 is connected and installed with the main circuit inlet of the second heat exchanger 4, the main circuit outlet of the second heat exchanger 4 is connected and installed with the first valve 5, the outlet of the first valve 5 is connected and installed with the top inlet of the third heat exchanger 6, the bottom outlet of the third heat exchanger 6 is connected and installed with the main circuit inlet of the fourth heat exchanger 8, the main circuit refrigerant outlet of the fourth heat exchanger 8 is connected and installed with the refrigerant inlet of the fifth heat exchanger 13, the refrigerant outlet of the fifth heat exchanger 13 is connected and installed with the auxiliary circuit refrigerant inlet of the second heat exchanger 4, and the auxiliary circuit refrigerant outlet of the second heat exchanger 4 is connected and installed with the refrigerant inlet of the gas-liquid separator 14.

[0019] Reference Figure 1The bypass pipe is connected to the inlet of the eighth valve 19, the outlet of the eighth valve 19 is connected to the refrigerant inlet of the fifth heat exchanger 13, and the bypass pipe is used for defrosting.

[0020] Referring to Figure 1 The outlet of the third heat exchanger 6 is connected to the second valve 7 and the second compressor 17, and the outlet of the second compressor 17 is connected to the refrigerant inlet of the fifth heat exchanger 13, which is used for defrosting of the compressor.

[0021] Referring to Figure 1 The outlet of the third heat exchanger 6 is connected to the fourth heat exchanger 8, and the outlet of the fourth heat exchanger 8 is connected to the first compressor 1, which is used for defrosting of the compressor.

[0022] Referring to Figure 1 The outlet of the third heat exchanger 6 is connected to the fourth heat exchanger 8, and the outlet of the fourth heat exchanger 8 is connected to the first compressor 1, which is used for defrosting of the compressor.

[0023] Referring to Figure 1 The outlet of the third heat exchanger 6 is connected to the fourth heat exchanger 8, and the outlet of the fourth heat exchanger 8 is connected to the first compressor 1, which is used for defrosting of the compressor.

[0024] Principle and advantages: in heating mode, the third valve 9, second compressor 17, eighth valve 19 cannot be powered on; the high temperature supercritical pressure gaseous refrigerant discharged by the first compressor 1 first enters the oil separator 2, the gaseous refrigerant is discharged from the top of the oil separator 2, the lubricating oil sinks under the action of the internal filter screen and is discharged from the bottom of the oil separator 2, returns to the gas-liquid separator 14 inlet through the capillary tube 15 under the suction of the first compressor 1 to ensure lubrication, the high temperature and high pressure gaseous refrigerant is cooled in the first heat exchanger 3 to become medium temperature and high pressure gaseous refrigerant, then enters the second heat exchanger 4 for further cooling, then enters the first valve 5 for throttling to become gaseous and liquid two-phase refrigerant, then enters the third heat exchanger 6 for flash evaporation to become part of saturated vapor and part of saturated liquid refrigerant, realizing pressure drop and supercooling, the saturated gaseous refrigerant is discharged from the gas pipe of the third heat exchanger 6 and returns to the intermediate gas inlet of the compressor through the sixth valve 16 to reduce the exhaust temperature and improve the system refrigerant circulation amount; the main road saturated liquid refrigerant enters the fourth heat exchanger 8, the third heat exchanger 6 bottom liquid pipe outlet and the fourth heat exchanger 8 main road refrigerant liquid pipe inlet middle pipeline bypass out a auxiliary road refrigerant into the third valve 9 to become low temperature and low pressure two-phase state refrigerant, absorbs the heat of the main road liquid refrigerant in the fourth heat exchanger 8, becomes low temperature and low pressure superheated gaseous refrigerant, is discharged from the gas pipe of the fourth heat exchanger 8 and enters the first compressor 1 through the seventh valve 18 and the saturated gaseous refrigerant from the third heat exchanger 6 to complete the gas supplement and enthalpy increase; the main road liquid refrigerant is further supercooled through the fourth heat exchanger 8, then flows through the fourth valve 10 to become low temperature and low pressure two-phase state refrigerant, evaporates and absorbs heat in the fifth heat exchanger 13 to become low temperature and low pressure superheated gaseous refrigerant, then is discharged from the fifth heat exchanger 13 and enters the second heat exchanger 4 for further heat absorption, then returns to the inlet of the gas-liquid separator 14 to complete the whole heating cycle;

[0025] In defrosting mode, when the system needs to be defrosted, the defrosting mode is determined according to the environment temperature: to ensure the hot water temperature effect, the heating of the embodiment is normally operated during defrosting. When the environment temperature is greater than 3℃, hot gas bypass defrosting is adopted; when-5℃≤environment temperature≤3℃, the combination of compressor defrosting and hot gas bypass defrosting is adopted; when the environment temperature is less than-5, compressor defrosting is adopted;

[0026] When hot gas bypass defrosting, the unit has little frost, and the eighth valve 19 is powered on; the high temperature and high pressure gaseous refrigerant flows through the eighth valve 19 for defrosting;

[0027] When the unit has more frost, it is judged according to the environment temperature, and the combination of compressor defrosting and hot gas bypass defrosting is adopted;

[0028] When the compressor defrosts, the sixth valve 16 is closed by losing power, the second valve 7 is opened by gaining power, and the second compressor 17 starts to absorb the saturated gaseous refrigerant discharged from the third heat exchanger 6 to compress it into high-temperature and high-pressure gaseous refrigerant, which enters the fifth heat exchanger 13 to defrost with the hot gas bypass combination to ensure the defrosting effect.

Claims

1. A carbon dioxide heat pump water heater, characterized in that... ,include: The first compressor (1), oil separator (2), first heat exchanger (3), second heat exchanger (4), first valve (5), third heat exchanger (6), second valve (7), fourth heat exchanger (8), third valve (9), fourth valve (10), fifth valve (11), liquid receiver (12), fifth heat exchanger (13), gas-liquid separator (14), capillary tube (15), sixth valve (16), second compressor (17), seventh valve (18), and eighth valve (19) are connected sequentially by copper pipes. The exhaust port of the first compressor (1) is connected to the inlet of the oil separator (2). The oil return pipe at the bottom of the oil separator (2) is connected to the capillary tube (15). The outlet of the capillary tube (15) is connected to the inlet of the gas-liquid separator (14). The top outlet of the oil separator (2) is connected to the refrigerant inlet of the first heat exchanger (3). The refrigerant outlet of the first heat exchanger (3) is connected to the main circuit inlet of the second heat exchanger (4). The refrigerant main circuit outlet of the second heat exchanger (4) is connected to the first valve (5). The outlet of the first valve (5) is connected to the top inlet of the third heat exchanger (6). The bottom outlet of the third heat exchanger (6) is connected to the main refrigerant inlet of the fourth heat exchanger (8). The main refrigerant outlet of the fourth heat exchanger (8) is connected to the refrigerant inlet of the fifth heat exchanger (13). The refrigerant outlet of the fifth heat exchanger (13) is connected to the auxiliary refrigerant inlet of the second heat exchanger (4). The auxiliary refrigerant outlet of the second heat exchanger (4) is connected to the refrigerant inlet of the gas-liquid separator (14).

2. A carbon dioxide heat pump water heater according to claim 1, characterized in that: A bypass pipe is connected between the oil separator (2) and the first heat exchanger (3) to the inlet of the eighth valve (19), and the outlet of the eighth valve (19) is connected to the refrigerant inlet of the fifth heat exchanger (13).

3. A carbon dioxide heat pump water heater according to claim 1, characterized in that: The outlet of the third heat exchanger (6) is connected to the second valve (7) and the second compressor (17), and the outlet of the second compressor (17) is connected to the refrigerant inlet of the fifth heat exchanger (13).

4. A carbon dioxide heat pump water heater according to claim 1, characterized in that: The third heat exchanger (6) is connected to the third valve (9) at the middle of the bottom liquid pipe outlet and the main refrigerant liquid pipe inlet of the fourth heat exchanger (8) via an auxiliary refrigerant pipe.

5. A carbon dioxide heat pump water heater according to claim 1, characterized in that: The third heat exchanger (6) and the second valve (7) are connected by a gas pipe at the bypass point between them and the inlet of the sixth valve (16). The outlet of the sixth valve (16) is connected to the outlet of the auxiliary gas pipe of the fourth heat exchanger (8).

6. A carbon dioxide heat pump water heater according to claim 1, characterized in that: A refrigerant pipeline is bypassed between the fourth valve (10) and the fifth heat exchanger (13) and connected to the fifth valve (11).

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