阅读说明：本技术 双喷气增焓制冷系统 (Double-enhanced vapor injection refrigeration system ) 是由 王有欣 熊琼 于 2021-10-13 设计创作，主要内容包括：本发明提供了一种双喷气增焓制冷系统,包括由管路依次接通并形成工质循环流路的压缩机、室内换热器、第一节流阀、室外换热器、气液分离器,压缩机为双喷气增焓压缩机,还包括：第一主路、第一辅路、第一辅助换热器；第二主路、第二辅路、第二辅助换热器；第二节流阀；第三节流阀；还包括第一辅路旁通电磁阀,以及第二辅路旁通电磁阀。通过以上结构,本发明单台压缩机实现三级压缩,可以根据具体制热工况条件,分别控制第一辅助换热器和/或第二辅助换热器单独或者共同工作提供喷气增焓,提供稳定的制热性能,从而解决了室外温度过低时,系统循环制冷剂量减少,制热性能急剧下降的问题。(The invention provides a double-enhanced vapor injection refrigeration system, which comprises a compressor, an indoor heat exchanger, a first throttling valve, an outdoor heat exchanger and a gas-liquid separator, wherein the compressor is sequentially communicated by pipelines and forms a working medium circulation flow path, the compressor is a double-enhanced vapor injection compressor, and the double-enhanced vapor injection refrigeration system also comprises: the system comprises a first main path, a first auxiliary path and a first auxiliary heat exchanger; the second main path, the second auxiliary path and the second auxiliary heat exchanger; a second throttle valve; a third throttle valve; the system also comprises a first auxiliary bypass electromagnetic valve and a second auxiliary bypass electromagnetic valve. Through the structure, the single compressor realizes three-stage compression, and can respectively control the first auxiliary heat exchanger and/or the second auxiliary heat exchanger to work independently or jointly to provide enhanced vapor injection and provide stable heating performance according to specific heating working conditions, so that the problems of reduced amount of circulating refrigerant of a system and rapid reduction of the heating performance when the outdoor temperature is too low are solved.)

1. A double-enhanced vapor injection refrigeration system comprises a compressor, an indoor heat exchanger, a first throttling valve, an outdoor heat exchanger and a gas-liquid separator which are sequentially communicated through pipelines and form a working medium circulation flow path, and is characterized in that the compressor is a double-enhanced vapor injection compressor;

the dual enhanced vapor injection refrigeration system further comprises:

a first auxiliary heat exchanger having a first main path and a first auxiliary path, the first main path being disposed between the first throttle valve and the indoor heat exchanger;

a second auxiliary heat exchanger having a second main path and a second auxiliary path, the second main path being arranged in series with the first main path;

a second throttle valve disposed between an outlet of the first main path and an inlet of the first sub-path;

a third throttle valve connecting an outlet of the second main path with an inlet of the second auxiliary path;

a first sub-passage bypass solenoid valve provided between an outlet of the first sub-passage and an inlet of the gas-liquid separator, and a second sub-passage bypass solenoid valve provided between an outlet of the second sub-passage and an inlet of the gas-liquid separator.

2. The dual enhanced vapor injection refrigeration system of claim 1,

the double enhanced vapor injection compressor comprises a first auxiliary air inlet and a second auxiliary air inlet which are arranged on the compressor;

an outlet of the first auxiliary path of the first auxiliary heat exchanger is communicated with the first auxiliary path air inlet, and an outlet of the second auxiliary path of the second auxiliary heat exchanger is communicated with the second auxiliary path air inlet;

the dual enhanced vapor injection refrigeration system further comprises a first auxiliary path electromagnetic valve arranged between the outlet of the first auxiliary path and the air inlet of the first auxiliary path, and a second auxiliary path electromagnetic valve arranged between the outlet of the second auxiliary path and the air inlet of the second auxiliary path.

3. The dual enhanced vapor injection refrigeration system of claim 2 further comprising first and second injection orifices disposed on the compressor corresponding to said first and second auxiliary air inlets, respectively,

the first and second injection holes are provided in the compressor in such a manner as not to be simultaneously clogged.

4. The dual enhanced vapor injection refrigeration system of claim 2 or 3, the first and second auxiliary heat exchangers being plate heat exchangers.

5. The dual enhanced vapor injection refrigeration system of claim 2 or 3 further comprising a first temperature sensor for detecting a discharge temperature of the compressor and a condensing pressure sensor for detecting a condensing pressure of the working fluid, and an enhanced vapor injection determination and control module configured to:

acquiring the exhaust temperature of a compressor and the working medium condensing pressure at the outlet of the compressor;

calculating the exhaust superheat degree according to the exhaust temperature and the working medium condensation pressure;

and controlling and adjusting the second throttle valve and/or the third throttle valve in response to the exhaust gas superheat being greater than a first prescribed threshold.

6. The dual enhanced vapor injection refrigeration system according to claim 5, further comprising a second temperature sensor for detecting an outdoor temperature, wherein the enhanced vapor injection judgment and control module controls and adjusts the opening degree of the second throttle valve and/or the third throttle valve according to a comparison result between the outdoor temperature and a preset temperature interval or according to a comparison result between the outdoor temperature and a first preset value.

7. The dual enhanced vapor injection refrigeration system of claim 6, further comprising a first temperature detection module for detecting a first auxiliary inlet temperature and a first auxiliary outlet temperature of a first auxiliary heat exchanger, wherein the enhanced vapor injection judgment and control module calculates a first auxiliary superheat degree according to a difference between the first auxiliary inlet temperature and the first auxiliary outlet temperature,

and controlling and adjusting the opening of the second throttle valve in response to the outdoor temperature being in the preset temperature interval and the first auxiliary road superheat degree being greater than a second specified threshold value.

8. The dual enhanced vapor injection refrigeration system of claim 7 wherein the adjustment of the opening of the second throttle valve is in a manner correlated to the first degree of side superheat.

9. The dual enhanced vapor injection refrigeration system of claim 6, further comprising a second temperature detection module for detecting a second auxiliary inlet temperature and a second auxiliary outlet temperature of a second auxiliary heat exchanger, wherein the enhanced vapor injection judgment and control module

Calculating a second degree of superheat of the auxiliary road based on a difference between the second auxiliary road inlet temperature and the second auxiliary road outlet temperature,

and controlling and adjusting the opening degrees of the third throttle valve and the second throttle valve in response to the outdoor temperature being less than the first preset value, the second auxiliary road superheat degree being greater than a third specified threshold value, and the first auxiliary road superheat degree being greater than a second specified threshold value.

10. A dual enhanced vapor injection refrigeration system as set forth in claim 9 wherein the adjustment of the opening of said third throttle valve is in a manner correlated to the superheat of said second auxiliary circuit.

11. The dual enhanced vapor injection refrigeration system according to claim 8 or 10, wherein when the superheat degree of the first auxiliary passage is greater than a predetermined superheat degree high threshold, the enhanced vapor injection judgment and control module issues instructions to increase the opening degree of the second throttle valve, open the first auxiliary passage solenoid valve, and close the first auxiliary passage bypass solenoid valve and the third throttle valve, or,

and when the second auxiliary path superheat degree is larger than a specified superheat degree high threshold value, the enhanced vapor injection judgment and control module sends out instructions for increasing the opening degree of the third throttle valve, opening the second auxiliary path electromagnetic valve and closing the second auxiliary path bypass electromagnetic valve.

12. The dual enhanced vapor injection refrigeration system according to any one of claims 8 or 10, wherein when the first or second degree of superheat of the auxiliary path falls within a specified degree of superheat, the enhanced vapor injection determination and control module issues an instruction to adjust the second throttle valve to a predetermined opening degree, close the first auxiliary path solenoid valve, and open the first auxiliary path bypass solenoid valve, or to adjust the third throttle valve to a predetermined opening degree, close the second auxiliary path solenoid valve, and open the second auxiliary path bypass solenoid valve.

13. The dual enhanced vapor injection refrigeration system according to any of claims 8 or 10, wherein the enhanced vapor injection judgment and control module controls the second throttle valve, the first auxiliary solenoid valve, and the first auxiliary solenoid valve, or the third throttle valve, the second auxiliary solenoid valve, and the second auxiliary solenoid valve to remain closed when the first auxiliary superheat degree or the second auxiliary superheat degree is less than a predetermined superheat degree low threshold.

14. The dual enhanced vapor injection refrigeration system of claim 2, further comprising a four-way valve, wherein four ports of the four-way valve are respectively communicated with the working medium inlet of the compressor, the working medium inlet of the gas-liquid separator, the working medium outlet of the outdoor heat exchanger and the working medium inlet of the indoor heat exchanger.

15. A dual enhanced vapor injection refrigeration system as set forth in claim 2 or claim 3 wherein said indoor heat exchanger comprises a plurality of sub-indoor heat exchangers connected in parallel.

16. The dual enhanced vapor injection refrigeration system of claim 5 wherein the enhanced vapor injection determination and control module controls the opening of the first throttle valve based on the value of the discharge temperature.

Technical Field

The invention relates to the technical field of air conditioners, in particular to a double enhanced vapor injection refrigeration system.

Background

When the outdoor air temperature is low, such as in winter in high latitudes in the north of china, the heat pump heating performance of the air conditioner is often not ideal. In order to compensate the deterioration of the heating performance of the heat pump caused by the temperature reduction of outdoor air and the overhigh system exhaust temperature at low temperature, the enhanced vapor injection technology is generally adopted at present.

Use the compressor of air injection enthalpy-increasing technique, can set up an induction port in the middle part of the compressor usually, the gaseous refrigerant that returns from the condenser gets into the middle chamber that this induction port reaches the compressor, reduce the temperature of middle chamber, thereby reduce the exhaust temperature of compressor export, reduce the exhaust superheat degree of compressor, reduce the length in the gaseous phase heat transfer district of condenser, increase two-phase heat transfer area, improve the heat exchange efficiency of condenser, the effect that can produce better when evaporating temperature and condensing temperature differ greatly, so the effect is more obvious under low temperature environment.

However, the enhanced vapor injection technology has certain problems, the existing enhanced vapor injection technology has good heating performance in the environment of minus 10 ℃ and above and can meet the heating requirements of people, but in severe cold regions such as minus 15 ℃, minus 20 ℃ and minus 30 ℃, the heating quantity of the enhanced vapor injection technology is rapidly attenuated, and the heating requirements of lower temperature regions cannot be met.

In addition, the size of the injection hole of the compressor is limited and it is periodically and repeatedly blocked by the movement of the winding shaft of the movable or fixed disk, so that there is an opening loss of the injection hole, about 40%, which increases flow resistance when the gas-phase refrigerant is injected into the compression chamber. Due to the increase of the flow resistance, the intermediate pressure of the two-phase refrigerant in the internal heat exchanger is increased, pressure loss occurs in the injection process, the injection flow is reduced, and the heating performance of the system is reduced.

Disclosure of Invention

Aiming at the problems, the invention provides a double enhanced vapor injection refrigeration system, which solves the technical problems that the heating quantity is rapidly attenuated and the heating effect is not ideal in the severe cold environment, such as the environment below-15 ℃ in the existing enhanced vapor injection refrigeration system.

The invention provides a double enhanced vapor injection refrigeration system, which comprises a compressor, an indoor heat exchanger, a first throttle valve, an outdoor heat exchanger and a gas-liquid separator, wherein the compressor is sequentially communicated by pipelines and forms a working medium circulation flow path, the compressor is a double enhanced vapor injection compressor, and the double enhanced vapor injection refrigeration system further comprises: the first auxiliary heat exchanger is provided with a first main path and a first auxiliary path, and the first main path is arranged between the first throttle valve and the indoor heat exchanger; the second auxiliary heat exchanger is provided with a second main path and a second auxiliary path, and the second main path is connected with the first main path in series; a second throttle valve provided between the outlet of the first main path and the inlet of the first sub path; a third throttle valve connecting the outlet of the second main path and the inlet of the second auxiliary path; a first sub-passage bypass solenoid valve provided between an outlet of the first sub-passage and an inlet of the gas-liquid separator, and a second sub-passage bypass solenoid valve provided between an outlet of the second sub-passage and an inlet of the gas-liquid separator.

According to the technical scheme, the working principle of the double enhanced vapor injection refrigeration system is as follows: after the refrigerant liquid in the first auxiliary path or the second auxiliary path is depressurized to a certain intermediate pressure through the second throttling valve or the third throttling valve, part of the liquid is evaporated to become a gas-liquid mixture with the intermediate pressure, and the gas-liquid mixture exchanges heat with the refrigerant liquid with higher temperature from the main path (the first main path or the second main path) in the first auxiliary heat exchanger or the second auxiliary heat exchanger. The refrigerant liquid part in the first auxiliary road or the second auxiliary road absorbs heat and is evaporated into gas to be supplemented into the working cavity of the compressor; meanwhile, the refrigerant in the main path is supercooled, and the supercooled refrigerant enters the outdoor heat exchanger after passing through the first throttling valve.

The refrigerant of the main path absorbs heat in low-temperature environment in the outdoor heat exchanger, and turns into low-pressure gas to enter the air suction port of the compressor, after being compressed for a period of time, the refrigerant from the main path and the refrigerant from the first and second auxiliary paths are mixed in the working cavity of the compressor, and are mixed while being compressed until the mixing process is finished, and the mixed refrigerant is further compressed by the compressor and then discharged out of the compressor. Therefore, the compressor sucks a part of the refrigerant gas with the intermediate pressure, and the refrigerant gas is mixed with the partially compressed refrigerant and then compressed, so that the process of realizing three-stage compression by using a single compressor is realized.

Therefore, according to the technical scheme of the invention, low-temperature gaseous refrigerant can directly enter the working cavity of the compressor through the first auxiliary path and/or the second auxiliary path, so that the temperature of the refrigerant in the compressor is reduced, and the amount of refrigerant circulated by the system is increased, thereby solving the problems that when the outdoor environment temperature is too low, the evaporation pressure and the evaporation temperature of the refrigerant are reduced, the compression ratio of the compressor is increased, the amount of refrigerant circulated by the system is reduced, the discharge pressure and the discharge temperature of the compressor are too high, and the heating performance of the system is reduced.

Particularly, the dual enhanced vapor injection compressor, the first auxiliary heat exchanger and the second auxiliary heat exchanger which are correspondingly arranged, the second throttle valve and the third throttle valve which are correspondingly arranged on the first auxiliary heat exchanger and the second auxiliary heat exchanger, the first auxiliary bypass electromagnetic valve and the second auxiliary bypass electromagnetic valve can respectively control the first auxiliary heat exchanger and/or the second auxiliary heat exchanger to independently or jointly work to provide enhanced vapor injection according to specific heating working condition conditions such as outdoor environment temperature, so that the dual enhanced vapor injection compressor can correspond to a lower-temperature external air environment and provide stable heating performance.

In addition, the first auxiliary bypass electromagnetic valve and the second auxiliary bypass electromagnetic valve are arranged, so that the first auxiliary bypass electromagnetic valve and/or the second auxiliary bypass electromagnetic valve can be conducted under the condition that the auxiliary refrigerant is judged not to be completely evaporated and gas-liquid mixing is possible according to the heat exchange condition of the auxiliary refrigerant, the refrigerant in the auxiliary is led into the gas-liquid separator, and the working safety of the compressor is guaranteed.

In an optional technical scheme of the invention, the double enhanced vapor injection compressor comprises a first auxiliary air inlet and a second auxiliary air inlet which are arranged on the compressor; an outlet of a first auxiliary path of the first auxiliary heat exchanger is communicated with a first auxiliary path air inlet, and an outlet of a second auxiliary path of the second auxiliary heat exchanger is communicated with a second auxiliary path air inlet; the dual enhanced vapor injection refrigeration system further comprises a first auxiliary path electromagnetic valve arranged between the outlet of the first auxiliary path and the first auxiliary path air inlet, and a second auxiliary path electromagnetic valve arranged between the outlet of the second auxiliary path and the second auxiliary path air inlet.

According to the technical scheme, the first auxiliary air inlet and the second auxiliary air inlet are arranged, so that the compressor is provided with two corresponding injection holes, the opening loss of the injection holes is reduced, the pressure loss in the enhanced vapor injection process is reduced, and the stable heating performance is provided.

The compressor sucks a part of refrigerant gas with intermediate pressure through the first auxiliary air inlet and the second auxiliary air inlet, and the refrigerant gas is mixed with partially compressed refrigerant and then compressed, so that the process of realizing three-stage compression by using a single compressor is realized.

According to the invention, the compressor is provided with the first auxiliary air inlet, the second auxiliary air inlet, the first auxiliary heat exchanger and the second auxiliary heat exchanger which are correspondingly arranged, the second throttling valve and the third throttling valve which are correspondingly arranged on the first auxiliary heat exchanger and the second auxiliary heat exchanger, and the first auxiliary bypass electromagnetic valve and the second auxiliary bypass electromagnetic valve, the first auxiliary heat exchanger and/or the second auxiliary heat exchanger can be respectively controlled to independently or jointly work to provide enhanced vapor injection according to specific heating working condition conditions such as outdoor environment temperature, so that the compressor can correspond to a lower temperature external air environment and provide stable heating performance.

In an optional technical scheme of the invention, the air conditioner further comprises a first injection hole and a second injection hole which are arranged on the compressor and respectively correspond to the first auxiliary air inlet and the second auxiliary air inlet, and the first injection hole and the second injection hole are arranged on the compressor in a mode of not being simultaneously blocked.

In an optional technical scheme of the invention, the first auxiliary heat exchanger and the second auxiliary heat exchanger are plate heat exchangers.

According to the technical scheme, the plate heat exchanger has the advantages of high heat exchange efficiency, small heat loss, compact and light structure, small occupied area, convenience in installation and cleaning, wide application and long service life; under the condition of the same pressure loss, the heat transfer coefficient of the heat exchanger is 3-5 times higher than that of the tubular heat exchanger, the occupied area of the heat exchanger is one third of that of the tubular heat exchanger, and the heat exchange efficiency is very high.

In an optional technical scheme of the invention, the system further comprises a first temperature sensor for detecting the exhaust temperature of the compressor, a condensation pressure sensor for detecting the condensation pressure of the working medium, and an enhanced vapor injection judgment and control module, wherein the enhanced vapor injection judgment and control module is configured to: acquiring the exhaust temperature of a compressor and the working medium condensing pressure at the outlet of the compressor; calculating the exhaust superheat degree according to the exhaust temperature and the working medium condensation pressure; and controlling and adjusting the second throttle valve and/or the third throttle valve in response to the exhaust gas superheat degree being larger than a first specified threshold value.

The effect of this preferred technical scheme lies in, according to the exhaust superheat degree (the difference between the temperature of refrigerant and the saturation temperature that refrigerant pressure corresponds at the compressor exit, it is higher than saturation temperature under this pressure, that is to say simply that the temperature of refrigerant is too high promptly), judges whether to get into the gas injection enthalpy-increasing operating mode.

Specifically, if the discharge superheat degree of the compressor is lower than a first specified threshold value (for example, 15 ℃ higher than the saturation temperature at the condensation pressure is the first specified threshold value), the second throttle valve and the third throttle valve are kept closed, the first auxiliary heat exchanger and the second auxiliary heat exchanger do not work, and the system is in a normal heating working condition. And if the exhaust superheat degree is larger than a first specified threshold value, entering a gas injection enthalpy increasing working condition, and controlling and adjusting the second throttle valve and/or the third throttle valve.

Further, in an optional technical scheme of the invention, the system further comprises a second temperature sensor for detecting the outdoor temperature, and the enhanced vapor injection judgment and control module controls and adjusts the opening degree of the second throttle valve and/or the third throttle valve according to a comparison result between the outdoor temperature and a preset temperature interval or a comparison result between the outdoor temperature and a first preset value.

According to the technical scheme, on the basis of the exhaust superheat degree of the compressor, whether the exhaust enthalpy increasing working condition is entered or not is judged by combining the comparison between the outdoor temperature and the preset temperature interval or the preset temperature value, and then the judgment is more accurate. Meanwhile, the working condition of specific exhaust enthalpy increase can be determined according to different preset temperatures, different external air temperatures can be corresponded, different exhaust enthalpy increase working conditions are realized, and the heating performance is improved.

In an optional technical scheme, the auxiliary air injection system further comprises a first temperature detection module used for detecting a first auxiliary road inlet temperature and a first auxiliary road outlet temperature of the first auxiliary heat exchanger, the air injection enthalpy judgment and control module calculates a first auxiliary road superheat degree according to a difference value of the first auxiliary road inlet temperature and the first auxiliary road outlet temperature, and the opening degree of the second throttle valve is controlled and adjusted in response to the fact that the outdoor temperature is in a preset temperature range and the first auxiliary road superheat degree is larger than a second specified threshold value.

According to the technical scheme, the first temperature detection module comprises two temperature sensors which are respectively arranged at the inlet and the outlet of the first auxiliary road, and the superheat degree of the first auxiliary road is calculated according to the inlet temperature and the outlet temperature of the first auxiliary road, which are acquired by the two temperature sensors; when the outdoor temperature is in a preset temperature interval, controlling and adjusting the opening of a second throttle valve according to the comparison result of the first auxiliary road superheat degree and a second specified threshold value, wherein the first auxiliary road superheat degree is larger than the second specified threshold value, and controlling to open the second throttle valve for increasing the vapor injection; and the opening degree of the second throttle valve is controlled corresponding to different outdoor temperatures and the superheat degree of the first auxiliary road, so that accurate temperature control is realized.

In an alternative embodiment of the present invention, the opening degree of the second throttle valve is adjusted in a manner correlated with the degree of superheat of the first sub-passage.

According to the technical scheme, the opening degree of the second throttle valve is timely adjusted according to the temperature of the superheat degree of the first auxiliary circuit, so that the superheat degree of the first auxiliary circuit can be controlled within a desired temperature range, in other words, if the superheat degree of the first auxiliary circuit is too high (for example, higher than 2 ℃), the opening degree of the second throttle valve is increased, so that more refrigerant enters the first auxiliary circuit to participate in throttling expansion, and heat is absorbed from the main circuit refrigerant, so that the superheat degree of the first auxiliary circuit refrigerant does not increase (for example, is kept at 2 ℃).

Meanwhile, if the superheat degree of the refrigerant of the first auxiliary circuit is too low, for example, lower than 0.5 degrees, the refrigerant of the auxiliary circuit is not completely evaporated at this time, and there is a case of gas-liquid mixing in part, and at this time, if the refrigerant directly enters the intermediate chamber of the compressor, the refrigerant liquid may cause impact on the compressor, thereby damaging the compressor. Therefore, the opening degree of the second throttle valve is adjusted (until closed) in accordance with the first degree of superheat of the sub-passage actually measured.

In an optional technical scheme, the system further comprises a second temperature detection module for detecting a second auxiliary road inlet temperature and a second auxiliary road outlet temperature of a second auxiliary heat exchanger, the jet enthalpy judgment and control module calculates a second auxiliary road superheat degree according to a difference value between the second auxiliary road inlet temperature and the second auxiliary road outlet temperature, and controls and adjusts the opening degrees of a third throttle valve and a second throttle valve in response to the outdoor temperature being smaller than a first preset value, the second auxiliary road superheat degree being larger than a third specified threshold value, and the first auxiliary road superheat degree being larger than a second specified threshold value.

According to the technical scheme, the second temperature detection module comprises two temperature sensors which are respectively arranged at the inlet and the outlet of the second auxiliary road, and the superheat degree of the second auxiliary road is calculated according to the inlet temperature and the outlet temperature of the second auxiliary road, which are acquired by the two temperature sensors; when the outdoor temperature is lower than the first preset value, the opening degrees of the second throttle valve and the third throttle valve are controlled and adjusted according to the comparison result of the first auxiliary road superheat degree and the second specified threshold value and the comparison result of the second auxiliary road superheat degree and the third specified threshold value, the flow of the refrigerant entering the compressor is improved, and the heating performance is optimized.

In an alternative embodiment of the present invention, the opening degree of the third throttle valve is adjusted in a manner correlated with the degree of superheat of the second auxiliary passage.

According to the technical scheme, the opening degree adjustment of the third regulating valve is basically the same as that of the second regulating valve, and the opening degree of the third throttle valve is timely regulated according to the temperature of the second auxiliary road superheat degree, so that the second auxiliary road superheat degree can be controlled within an ideal temperature range.

For example, if the degree of superheat of the second sub-circuit is too high (e.g., above 2 ℃), the third throttle opening is increased so that more refrigerant enters the second sub-circuit to participate in the throttling expansion, thereby absorbing heat from the main circuit refrigerant so that the degree of superheat of the second sub-circuit refrigerant does not increase (e.g., remains at 2 ℃). Meanwhile, if the superheat degree of the refrigerant of the second auxiliary path is too low, for example, lower than 0.5 degree, the refrigerant of the second auxiliary path is not completely evaporated at this time, and there is a case of gas-liquid mixing partially, and at this time, if the refrigerant directly enters the compressor intermediate chamber, the refrigerant liquid may cause impact on the compressor, thereby damaging the compressor. Therefore, the opening degree of the third throttle valve is adjusted (until closed) in accordance with the actually measured second degree of superheat of the auxiliary passage.

In an optional technical scheme of the invention, when the first auxiliary road superheat degree is greater than a specified superheat degree high threshold, the enhanced vapor injection judging and controlling module sends out instructions for increasing the opening degree of the second throttle valve, opening the first auxiliary road electromagnetic valve and closing the first auxiliary road bypass electromagnetic valve and the third throttle valve, or when the second auxiliary road superheat degree is greater than the specified superheat degree high threshold, the enhanced vapor injection judging and controlling module sends out instructions for increasing the opening degree of the third throttle valve, opening the second auxiliary road electromagnetic valve and closing the second auxiliary road bypass electromagnetic valve.

According to this aspect, if the degree of superheat of the first sub-passage is too large, the flow rate of the refrigerant of the first sub-passage is increased to reduce the degree of superheat of the sub-passage refrigerant, and the opening degree of the second throttle valve is determined based on whether the degree of superheat meets a degree of superheat high threshold. At this time, the second sub-path does not operate. Since the refrigerant flow in the main circuit is now reduced, the superheat in the second auxiliary circuit may be too high if the third throttle is opened, which is detrimental to the overall operation of the system.

In an optional technical scheme of the invention, when the first auxiliary road superheat degree or the second auxiliary road superheat degree falls into a specified superheat degree range, the enhanced vapor injection judgment and control module sends out instructions for adjusting the second throttle valve to a preset opening degree, closing the first auxiliary road electromagnetic valve and opening the first auxiliary road bypass electromagnetic valve, or sending out instructions for adjusting the third throttle valve to a preset opening degree, closing the second auxiliary road electromagnetic valve and opening the second auxiliary road bypass electromagnetic valve.

According to the technical scheme, when the first auxiliary path superheat degree or the second auxiliary path superheat degree falls into the specified superheat degree range, gas and liquid can be mixed, so that the first auxiliary path bypass electromagnetic valve and the second auxiliary path bypass electromagnetic valve are opened, the refrigerant enters the gas-liquid separator, the liquid refrigerant is prevented from entering the compressor, and the working safety of the compressor is ensured.

In an optional technical scheme of the invention, when the first auxiliary road superheat degree or the second auxiliary road superheat degree is less than a specified superheat degree low threshold value, the enhanced vapor injection judgment and control module controls the second throttle valve, the first auxiliary road solenoid valve and the first auxiliary road bypass solenoid valve or controls the third throttle valve, the second auxiliary road solenoid valve and the second auxiliary road bypass solenoid valve to be kept closed.

According to the technical scheme, even if the outdoor temperature is low and the compressor needs enhanced vapor injection due to exhaust overheating, if the first auxiliary channel overheating degree or the second auxiliary channel overheating degree is still too low through adjustment, for example, the first auxiliary channel overheating degree or the second auxiliary channel overheating degree is lower than 0.5 degree, in order to ensure the safety of the compressor, the condition of enhanced vapor injection is not entered.

In the optional technical scheme of the invention, four ports of the four-way valve are respectively communicated with the working medium inlet of the compressor, the working medium inlet of the gas-liquid separator, the working medium outlet of the outdoor heat exchanger and the working medium inlet of the indoor heat exchanger.

According to the technical scheme, the flow direction of the refrigerant can be changed through the switching of the four-way valve, so that the double-enhanced vapor injection refrigeration system can be switched under different operation modes, and a user can conveniently switch to a required operation mode according to requirements.

In an optional technical scheme of the invention, the indoor heat exchanger comprises a plurality of sub-indoor heat exchangers arranged in parallel.

According to the technical scheme, the enhanced vapor injection refrigeration system can be used as a multi-split system, one outdoor heat exchanger is connected with a plurality of sub-indoor heat exchangers, the occupied space of the outdoor heat exchanger is saved, one sub-indoor heat exchanger can be independently started, and the plurality of sub-indoor heat exchangers can be simultaneously started, so that the control is more flexible and energy-saving, and the centralized management of the sub-indoor heat exchangers is convenient to realize.

In an optional technical scheme of the invention, the enhanced vapor injection judgment and control module controls the opening of the first throttle valve according to the numerical value of the exhaust temperature.

According to this embodiment, the opening degree of the first throttle valve is controlled according to the discharge temperature, and for example, when the discharge temperature is high, the opening degree of the first throttle valve is increased, the flow rate of the refrigerant in the system is increased, and the suction temperature of the compressor is reduced, which has the effect of helping the discharge temperature to be lowered.

Drawings

Fig. 1 is a schematic structural diagram of a dual enhanced vapor injection refrigeration system in an embodiment of the present invention.

Fig. 2 is a schematic flow diagram of a refrigerant of a dual enhanced vapor injection refrigeration system in an embodiment of the present invention when an outdoor temperature is lower than a preset temperature value, a first auxiliary superheat degree is greater than a second predetermined threshold, and the second auxiliary superheat degree falls within a predetermined superheat degree range.

Fig. 3 and 4 are schematic flow diagrams of a control method for a dual enhanced vapor injection refrigeration system according to an embodiment of the present invention, which is divided into two graphical representations due to picture size limitations.

Reference numerals:

a compressor 1; a first side air inlet 11; a second bypass air inlet 12; an air suction port 13; an indoor heat exchanger 2; a first indoor heat exchanger 2 a; a second indoor heat exchanger 2 b; an outdoor heat exchanger 3; a gas-liquid separator 4; first throttle valve EXV 1; second throttle valve EXV 2; a third throttle valve EXV 3; a first auxiliary solenoid valve SV 1; a second auxiliary solenoid valve SV 3; a first bypass solenoid valve SV 2; a second bypass solenoid valve SV 4; a first main route 51; a first side road 52; the first auxiliary heat exchanger 53; a second main road 61; a second side road 62; a second auxiliary heat exchanger 63; a first temperature sensor T5; a second temperature sensor T4; a temperature sensor T6A; a temperature sensor T6B; a temperature sensor T7A; a temperature sensor T7B; a condensing pressure sensor P; a throttle valve sva; a throttle valve svb.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, 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 invention.

Fig. 1 is a schematic structural diagram of a dual enhanced vapor injection refrigeration system according to an embodiment of the present invention. Referring to fig. 1, an embodiment of the present invention provides a dual enhanced vapor injection refrigeration system, including a compressor 1, an indoor heat exchanger 2, a first throttle valve EXV1, an outdoor heat exchanger 3, and a gas-liquid separator 4, which are sequentially connected by a pipeline and form a working medium circulation flow path, and the dual enhanced vapor injection refrigeration system further includes: a first and a second bypass air inlet 11 and 12 provided at the compressor 1; a first auxiliary heat exchanger 53 having a first main path 51 and a first auxiliary path 52, wherein the first main path 51 is disposed between the first throttle valve EXV1 and the indoor heat exchanger 2; a second auxiliary heat exchanger 63 having a second main circuit 61 and a second auxiliary circuit 62, wherein the second main circuit 61 is arranged in series with the first main circuit 51; a second throttle valve EXV2 provided between the outlet of the first main path 51 and the inlet of the first sub path 52; a third throttle valve EXV3 connecting the outlet of the second main path 61 with the inlet of the second auxiliary path 62; the outlet of the first auxiliary path 52 of the first auxiliary heat exchanger 53 is communicated with the first auxiliary path air inlet 11, and the outlet of the second auxiliary path 62 of the second auxiliary heat exchanger 63 is communicated with the second auxiliary path air inlet 12; a first auxiliary passage solenoid valve SV1 provided between the outlet of the first auxiliary passage 52 and the first auxiliary passage intake port 11, and a second auxiliary passage solenoid valve SV3 provided between the outlet of the second auxiliary passage 63 and the second auxiliary passage intake port 12; a first sub-passage bypass solenoid valve SV2 provided between the outlet of the first sub-passage 52 and the inlet of the gas-liquid separator 4, and a second sub-passage bypass solenoid valve SV4 provided between the outlet of the second sub-passage 62 and the inlet of the gas-liquid separator 4.

Through the way, the working principle of the double enhanced vapor injection refrigeration system in the embodiment of the invention is as follows: after the refrigerant liquid in the first auxiliary circuit 52 or the second auxiliary circuit 62 is depressurized to a certain intermediate pressure by the second throttle valve EXV2 or the third throttle valve EXV3, part of the liquid is evaporated to become a gas-liquid mixture of an intermediate pressure, and heat exchange occurs with the refrigerant liquid of a higher temperature from the main circuit (the first main circuit 51 or the second main circuit 61) in the first auxiliary heat exchanger 53 or the second auxiliary heat exchanger 63. The liquid refrigerant in the first or second auxiliary path 52 or 62 absorbs heat and evaporates to become gas, and is supplemented into the working chamber of the compressor (not shown in the figure) through the first or second auxiliary path air inlet 11 or 12 of the compressor 1; meanwhile, the refrigerant of the main path is supercooled, and the supercooled refrigerant passes through the first throttle EXV1 and then enters the outdoor heat exchanger 3.

The refrigerant in the main path absorbs heat in the low-temperature environment in the outdoor heat exchanger 3, and turns into low-pressure gas to enter the suction port 13 of the compressor 1, after being compressed for a while, the refrigerant from the main path is mixed with the refrigerant from the first auxiliary path 52 and the second auxiliary path 62 in the working chamber of the compressor, and the refrigerant is mixed while being compressed until the mixing process is finished, and the mixed refrigerant is further compressed by the compressor 1 and then discharged out of the compressor 1. Therefore, the compressor 1 sucks a part of the refrigerant gas of the intermediate pressure through the first sub-path air inlet 11 and the second sub-path air inlet 12, mixes the sucked part of the refrigerant gas with the partially compressed refrigerant, and then compresses the mixture, thereby realizing a three-stage compression process with a single compressor.

Therefore, in the embodiment of the present invention, the low-temperature gaseous refrigerant can directly enter the compressor working chamber through the first auxiliary path 52 and/or the second auxiliary path 62, so as to reduce the temperature of the refrigerant inside the compressor 1, and increase the amount of refrigerant circulating in the system, thereby solving the problems that when the outdoor ambient temperature is too low, the refrigerant evaporation pressure and evaporation temperature are reduced, which results in that the compression ratio of the compressor 1 is increased, the amount of refrigerant circulating in the system is reduced, which results in that the discharge pressure and discharge temperature of the compressor 1 are too high, and the heating performance of the system is reduced.

In particular, the embodiment of the present invention may control the first auxiliary heat exchanger 53 and/or the second auxiliary heat exchanger 63 to individually or jointly operate to provide enthalpy increase according to a specific heating condition, such as an outdoor ambient temperature, by providing the first auxiliary air inlet 11 and the second auxiliary air inlet 12, the first auxiliary heat exchanger 53 and the second auxiliary heat exchanger 63 provided corresponding to the first auxiliary air inlet 11 and the second auxiliary air inlet 12, the second throttle valve EXV2 and the third throttle valve EXV3 provided corresponding to the first auxiliary heat exchanger 53 and the second auxiliary heat exchanger 63, and the first auxiliary solenoid valve SV1, the second auxiliary solenoid valve SV3, the first auxiliary solenoid valve SV2 and the second auxiliary solenoid valve SV4 in the compressor 1, so that stable heating performance may be provided corresponding to a lower temperature outdoor air environment.

Meanwhile, the first auxiliary air inlet 11 and the second auxiliary air inlet 12 are arranged, so that the compressor is provided with two corresponding injection holes, the opening loss of the injection holes is reduced, the pressure loss in the enhanced vapor injection process is reduced, and the stable heating performance is provided.

In addition, the first auxiliary bypass solenoid valve SV2 and the second auxiliary bypass solenoid valve SV4 are arranged, so that the first auxiliary bypass solenoid valve SV2 and/or the second auxiliary bypass solenoid valve SV4 can be conducted to lead the refrigerant in the auxiliary circuit into the gas-liquid separator 4 under the condition that the auxiliary refrigerant is judged not to be completely evaporated and gas-liquid mixing is possible according to the heat exchange condition of the auxiliary refrigerant, and the working safety of the compressor 1 is ensured.

The dual enhanced vapor injection refrigeration system provided by the embodiment of the invention has no attenuation of the heating performance at minus 20 ℃, and simultaneously, the attenuation of the heating performance of the system is not more than 15% under the conditions of the heating operation range of minus 30 ℃ and minus 30 ℃, so that the heating requirements of users in a low-temperature environment are met.

In a preferred embodiment of the present invention, a first injection hole (not shown) and a second injection hole (not shown) provided in the compressor 1 to correspond to the first and second sub intake ports 11 and 12, respectively, are further included, and the first and second injection holes are provided in the compressor 1 in such a manner as not to be simultaneously clogged.

Through the mode, the first injection hole and the second injection hole are arranged in a mode of not being blocked simultaneously, namely, the condition that at least one injection hole is not blocked exists, the gas injection is ensured, the opening loss of the injection hole is reduced, the pressure loss in the enhanced vapor injection process is reduced, and the stable heating performance is provided.

In a preferred embodiment of the present invention, the compressor 1 is a scroll compressor, the first auxiliary air inlet 11 or the first injection hole is disposed close to the air suction port 13 of the compressor 1, and the second auxiliary air inlet 12 or the second injection hole has a central angle of 180 ° with the first auxiliary air inlet 11 or the first injection hole in the compression direction of the refrigerant (the direction in which the refrigerant moves from the position of the air suction port to the position of the air discharge port of the compressor), so that the first injection hole and the second injection hole are prevented from approaching each other in the compression chamber, resulting in excessively close air-supply pressures of the first auxiliary air inlet 11 and the second auxiliary air inlet 12, and the three-stage compression is changed into two-stage compression, resulting in poor air-injection enthalpy effect.

It should be noted that the schematic structural diagrams of the compressor in fig. 1 and 2 of the present invention mainly represent the three-stage compression process of the compressor, and do not really reflect the internal structure of the compressor, and the air inlet 13, the first auxiliary air inlet 11 and the second auxiliary air inlet 12 are actually on the same plane.

In a preferred embodiment of the present invention, the first auxiliary heat exchanger 53 and the second auxiliary heat exchanger 63 are plate heat exchangers, and the main path inlet, the main path outlet, the auxiliary path inlet, and the auxiliary path outlet are conventional structures of the plate heat exchangers, and are not described herein again.

Through the mode, the plate heat exchanger has the advantages of high heat exchange efficiency, small heat loss, compact and light structure, small occupied area, convenience in installation and cleaning, wide application and long service life; under the condition of the same pressure loss, the heat transfer coefficient of the heat exchanger is 3-5 times higher than that of the tubular heat exchanger, the occupied area of the heat exchanger is one third of that of the tubular heat exchanger, and the heat exchange efficiency is very high.

In a preferred embodiment of the present invention, the system further includes a first temperature sensor T5 for detecting a discharge temperature of the compressor, a condensation pressure sensor P for detecting a condensation pressure of the working medium, and an enhanced vapor injection determination and control module (not shown in the figure), the enhanced vapor injection determination and control module is configured to: acquiring the exhaust temperature of the compressor 1 and the working medium condensing pressure at the outlet of the compressor 1; calculating the exhaust superheat degree according to the exhaust temperature and the working medium condensation pressure; in response to the exhaust superheat being greater than a first prescribed threshold, control adjusts the second throttle EXV2 and/or the third throttle EXV 3.

According to the embodiment of the invention, whether the gas injection enthalpy-increasing working condition is entered is judged according to the exhaust superheat degree of the compressor (the temperature difference between the temperature of the refrigerant at the outlet of the compressor 1 and the saturation temperature corresponding to the pressure of the refrigerant, namely the temperature of the refrigerant is higher than the saturation temperature under the pressure, namely the exhaust temperature is overhigh).

Specifically, if the degree of superheat of the discharge gas of the compressor 1 is lower than a first prescribed threshold value (for example, 15 ℃ higher than the saturation temperature at the condensing pressure is the first prescribed threshold value), the second throttle valve EXV2 and the third throttle valve EXV3 are kept closed, the first auxiliary heat exchanger 53 and the second auxiliary heat exchanger 63 are not operated, and the system is in a normal heating condition. And if the exhaust superheat degree is larger than a first specified threshold value, entering an exhaust enthalpy increasing working condition.

Further, in a preferred embodiment of the present invention, on the basis of the exhaust superheat degree of the compressor 1, the outdoor temperature is compared with the preset temperature interval or the preset temperature value to determine whether the exhaust enthalpy-increasing operating condition is entered, so that the determination is more accurate.

The dual enhanced vapor injection refrigeration system further comprises a second temperature sensor T4 for detecting the outdoor temperature, and the enhanced vapor injection judgment and control module controls and adjusts the opening degree of the second throttle valve EXV2 and/or the third throttle valve EXV3 according to the comparison result between the outdoor temperature and the preset temperature interval or the comparison result between the outdoor temperature and the first preset value.

According to the embodiment of the invention, by combining the comparison of the outdoor temperature and the preset temperature interval or the preset temperature value, the specific exhaust enthalpy-increasing working condition can be determined according to different preset temperatures, different exhaust enthalpy-increasing working conditions can be realized corresponding to different external air temperatures, and the heating performance is further improved. In the specific embodiment of the invention, the preset temperature interval is-13 ℃ to 7 ℃, the preset temperature value is-13 ℃, the outdoor temperature is lower than-13 ℃, and the opening degrees of the second throttle valve EXV2 and the third throttle valve EXV3 are correspondingly adjusted; the outdoor temperature is between-13 ℃ and 7 ℃, and the enhanced vapor injection judgment and control module controls and adjusts the opening degree of the second throttle valve EXV2 or the third throttle valve EXV 3.

Specifically, the dual enhanced vapor injection refrigeration system according to the embodiment of the present invention further includes a first temperature detection module (including a temperature sensor T6A and a temperature sensor T7A, respectively disposed at the inlet and the first auxiliary outlet of the first auxiliary circuit) for detecting a first auxiliary circuit inlet temperature and a first auxiliary circuit outlet temperature of the first auxiliary heat exchanger 53, and calculating a first auxiliary circuit superheat degree according to a difference between the inlet temperature and the outlet temperature of the first auxiliary circuit obtained by the two temperature sensors T6A and T7A, and the enhanced vapor injection judgment and control module calculates the first auxiliary circuit superheat degree according to a difference between the first auxiliary circuit inlet temperature and the first auxiliary circuit outlet temperature, and controls and adjusts the opening degree of the second throttle valve EXV2 in response to that the outdoor temperature is in a preset temperature range and the first auxiliary circuit superheat degree is greater than a second predetermined threshold value.

The dual enhanced vapor injection refrigeration system further comprises a second temperature detection module (comprising a temperature sensor T6B and a temperature sensor T7B, and two temperature sensors T7A and T7B respectively arranged at the inlet of the second auxiliary road and the outlet of the second auxiliary road, wherein the inlet temperature and the outlet temperature of the second auxiliary road are obtained through the two temperature sensors, and the superheat degree of the second auxiliary road is calculated according to the difference value of the inlet temperature and the outlet temperature), the enhanced vapor injection judgment and control module calculates the superheat degree of the second auxiliary road according to the difference value of the inlet temperature of the second auxiliary road and the outlet temperature of the second auxiliary road, and responds that the outdoor temperature is less than the first preset value, and the second auxiliary road superheat degree is larger than a third specified threshold value, and the first auxiliary road superheat degree is larger than a second specified threshold value, and the opening degrees of the third throttle valve EXV3 and the second throttle valve EXV2 are controlled and adjusted.

Through the mode, the specific air injection enthalpy increasing working condition is determined and the opening degree of the second throttle valve EXV2 and/or the third throttle valve EXV3 is/are timely adjusted according to the comparison between the first auxiliary air passage superheat degree and the second auxiliary air passage superheat degree and the corresponding first specified threshold value and second specified threshold value, so that the reliable and stable operation of the double air injection enthalpy increasing refrigerating system is ensured.

In a preferred embodiment of the present invention, the opening degree adjustment of the second throttle valve EXV2 is performed in a manner correlated with the degree of superheat of the first sub passage.

Specifically, the opening degree of the second throttle valve EXV2 is adjusted in due time in accordance with the temperature of the first sub-circuit superheat degree, so that the first sub-circuit superheat degree can be controlled within a desired temperature range. In other words, if the first sub-circuit superheat is too high (e.g., above 2 ℃), the opening degree of the second throttle EXV2 is increased, so that more refrigerant enters the first sub-circuit 52 to participate in the throttle expansion, thereby absorbing heat from the main circuit refrigerant, so that the first sub-circuit superheat does not increase (e.g., remains at 2 ℃).

Meanwhile, if the degree of superheat of the refrigerant of the first sub-circuit 52 is too low, for example, less than 0.5 degrees, the refrigerant of the first sub-circuit is not completely evaporated at this time, and there is a case where gas and liquid are mixed partially, and at this time, if the refrigerant directly enters the compressor intermediate chamber, the refrigerant liquid may cause an impact on the compressor 1, thereby damaging the compressor 1. Therefore, the opening degree of the second throttle valve EXV2 is adjusted (until closed) in accordance with the first degree of superheat of the sub-passage actually measured.

In a preferred embodiment of the present invention, the opening degree of the third throttle valve EXV3 is adjusted in a manner correlated with the degree of superheat of the second sub passage.

Specifically, the opening degree of the third throttle valve EXV3 is adjusted in time according to the temperature of the second auxiliary circuit superheat degree, so that the second auxiliary circuit superheat degree can be controlled within a desired temperature range, in other words, if the second auxiliary circuit superheat degree is too high (e.g., higher than 2 ℃), the opening degree of the third throttle valve EXV3 is increased, so that more refrigerant enters the second auxiliary circuit 52 to participate in throttling expansion, thereby absorbing heat from the main circuit refrigerant, so that the superheat degree of the refrigerant of the second auxiliary circuit 52 does not increase (e.g., is maintained at 2 ℃).

Meanwhile, if the degree of superheat of the refrigerant of the second sub-circuit 52 is too low, for example, less than 0.5 degrees, the refrigerant of the second sub-circuit 52 is not completely evaporated at this time, and there is a case where gas and liquid are mixed partially, and at this time, if the refrigerant directly enters the compressor intermediate chamber, the refrigerant liquid may cause an impact on the compressor 1, thereby damaging the compressor. Therefore, the opening degree of the third throttle valve EXV3 is adjusted (until closed) according to the second sub-circuit superheat degree actually measured.

In a preferred embodiment of the present invention, when the first auxiliary superheat degree is greater than the predetermined high superheat degree threshold, the enhanced vapor injection determination and control module issues commands to increase the opening of the second throttle valve EXV2, open the first auxiliary solenoid valve SV1, and close the first auxiliary bypass solenoid valve SV2 and the third throttle valve EXV3, or,

when the second auxiliary road superheat degree is larger than the specified superheat degree high threshold value, the enhanced vapor injection judgment and control module sends out instructions for increasing the opening degree of the third throttle valve EXV3, opening the second auxiliary road electromagnetic valve SV3 and closing the second auxiliary road electromagnetic valve SV 4.

In the above manner, if the first sub circuit superheat is excessively greater than 2 ℃, the refrigerant flow rate of the first sub circuit is increased to reduce the degree of superheat of the sub circuit refrigerant, and the opening degree of the second throttle valve EXV2 is determined according to whether the degree of superheat meets the degree of superheat high threshold value. At this time, the second sub-path 62 does not operate. Since the refrigerant flow of the main circuit is reduced at this time, the superheat of the second auxiliary circuit 62 may be large if the third throttle EXV3 is opened, which is detrimental to the overall operation of the system. Or, if the degree of superheat of the second sub-circuit is too large (e.g., exceeds 2 ℃), the refrigerant flow rate of the second sub-circuit 62 is increased to reduce the degree of superheat of the sub-circuit refrigerant, and the opening degree of the third throttle EXV3 is determined according to whether the degree of superheat is combined with a high degree of superheat threshold, at this time, the first sub-circuit 52 does not operate, and the principle is the same as that, and is not described herein again.

In a preferred embodiment of the present invention, when the first or second degree of superheat of the auxiliary circuit falls within a prescribed degree of superheat range, the enhanced vapor injection determination and control module issues commands to adjust the second throttle valve EXV2 to a predetermined opening degree, close the first auxiliary circuit solenoid valve SV1 and open the first auxiliary circuit solenoid valve SV2, or to adjust the third throttle valve EXV3 to a predetermined opening degree, close the second auxiliary circuit solenoid valve SV3 and open the second auxiliary circuit solenoid valve SV 4.

In such a way, when the first auxiliary bypass superheat degree or the second auxiliary bypass superheat degree falls in a specified superheat degree range (such as 0.5-1 ℃), gas and liquid can be mixed, so that the first auxiliary bypass solenoid valve SV2 and/or the second auxiliary bypass solenoid valve SV4 are/is opened, the refrigerant enters the gas-liquid separator 4, the liquid refrigerant is prevented from entering the compressor 1, and the working safety of the compressor 1 is ensured.

In a preferred embodiment of the present invention, the enhanced vapor injection determination and control module controls the second throttle valve EXV2, the first auxiliary path solenoid valve SV1, and the first auxiliary path bypass solenoid valve SV2, or the third throttle valve EXV3, the second auxiliary path solenoid valve SV3, and the second auxiliary path bypass solenoid valve SV4 to remain closed when the first auxiliary path superheat degree or the second auxiliary path superheat degree is less than the predetermined superheat degree low threshold.

Through the mode, even if the outdoor temperature is low and the compressor is overheated to exhaust gas and needs enhanced vapor injection, if the degree of superheat of the first auxiliary passage or the degree of superheat of the second auxiliary passage is still too low through adjustment, for example, the degree of superheat of the first auxiliary passage or the degree of superheat of the second auxiliary passage is lower than 0.5 degree, and the condition of enhanced vapor injection is not entered in order to ensure the safety of the compressor 1.

In some embodiments, in response to the exhaust superheat being below a first prescribed threshold, the enhanced vapor injection determination and control module controls the second throttle valve EXV2, the first auxiliary bypass solenoid valve SV1, and the first auxiliary bypass solenoid valve SV2, the third throttle valve EXV3, the second auxiliary bypass solenoid valve SV3, and the second auxiliary bypass solenoid valve SV4 to all remain closed.

In the preferred embodiment of the invention, the heat exchanger further comprises a four-way valve 7, and four ports of the four-way valve 7 are respectively communicated with the working medium inlet of the compressor 1, the working medium inlet of the gas-liquid separator 4, the working medium outlet of the outdoor heat exchanger 3 and the working medium inlet of the indoor heat exchanger 2.

Through the mode, the flow direction of the refrigerant can be changed through the switching of the four-way valve 7, so that the double-enhanced vapor injection refrigeration system is switched under different operation modes, and a user can conveniently switch to a required operation mode according to requirements.

In a preferred embodiment of the present invention, the indoor heat exchanger 2 includes a plurality of sub-indoor heat exchangers arranged in parallel, and as shown in fig. 1, the indoor heat exchanger 2 includes a first indoor heat exchanger 2a and a second indoor heat exchanger 2b, and the first indoor heat exchanger 2a and the second indoor heat exchanger 2b are connected in parallel. Further, the first indoor heat exchanger 2a and the second indoor heat exchanger 2b are respectively connected in series and then connected in parallel with the electromagnetic valves sva and svb, so that the individual operation of the sub-indoor heat exchangers can be controlled according to the requirement.

In the embodiment of the invention, the double enhanced vapor injection refrigeration system further comprises a stop valve, and the stop valve connects the indoor part and the outdoor part of the double enhanced vapor injection refrigeration system to form a complete refrigeration cycle system.

Through the mode, the enhanced vapor injection refrigeration system can be used as a multi-split system, one outdoor heat exchanger is connected with the plurality of sub-indoor heat exchangers, the occupied space of the outdoor heat exchanger is saved, one sub-indoor heat exchanger can be independently started, the plurality of sub-indoor heat exchangers can be simultaneously started, the control is more flexible and energy-saving, and the centralized management of the sub-indoor heat exchangers is convenient to realize.

In a preferred embodiment of the present invention, the enhanced vapor injection determination and control module controls the opening degree of the first throttle valve EXV1 based on the value of the exhaust gas temperature.

In this way, the opening degree of the first throttle valve EXV1 is controlled according to the discharge temperature, for example, when the discharge temperature is high, the opening degree of the first throttle valve EXV1 is increased, the flow rate of the refrigerant in the system is increased, the compressor suction temperature is reduced, and there is an effect of helping to reduce the discharge temperature.

Specifically, when the compressor exhaust temperature is greater than or equal to 85 ℃, the opening degree of the first throttle valve EXV1 reaches the maximum, the compressor exhaust temperature 85 is greater than or equal to T5 is greater than or equal to 80, the opening degree of the first throttle valve EXV1 is 420, the compressor exhaust temperature 85 is greater than or equal to T5 is greater than or equal to 80, the opening degree of the first throttle valve EXV1 is 420, the compressor exhaust temperature 80 is greater than or equal to T5 is greater than or equal to 70, the opening degree of the first throttle valve EXV1 is 360, the compressor exhaust temperature 70 is greater than or equal to T5 is greater than or equal to 65, the opening degree of the first throttle valve EXV1 is 300, the compressor exhaust temperature 65 is greater than or equal to T5 is greater than or equal to 60, the opening degree of the first throttle valve EXV1 is 240, the compressor exhaust temperature 60 is greater than or equal to T5 is greater than or equal to 55, the opening degree of the first throttle valve EXV1 is 180, the compressor exhaust temperature 55 is greater than or equal to T5 is greater than or equal to 50, the opening degree of the first throttle valve EXV1 is 120, the compressor exhaust temperature T5 is less than 50, and the opening degree of the first throttle valve EXV1 is 80.

In a specific embodiment of the invention, the dual enhanced vapor injection refrigeration system further comprises a storage module and a control module, which are used for storing the judgment values of the outdoor environment temperature, the inlet temperature of the first auxiliary road, the outlet temperature of the first auxiliary road, the inlet temperature of the second auxiliary road, the outlet temperature of the second auxiliary road, the first specified threshold, the second specified threshold, the third specified threshold, the specified superheat range, the specified superheat low threshold, the specified superheat high threshold, the refrigerant saturated liquid temperature and the exhaust superheat degree corresponding to the refrigerant condensation pressure, the exhaust temperature and the like detected by the temperature sensors in real time; the control module controls opening degrees of a first throttle valve EXV1, a second throttle valve EXV2, a third throttle valve EXV3, a first auxiliary road electromagnetic valve SV1, a first auxiliary road electromagnetic valve SV2, a second auxiliary road electromagnetic valve SV3, a second auxiliary road electromagnetic valve SV4, a throttle valve sva and a throttle valve svb according to judgment results of exhaust temperature, exhaust superheat degree, first auxiliary road superheat degree, second auxiliary road superheat degree and the like.

The structural schematic diagram of the dual enhanced vapor injection refrigeration system according to the embodiment of the present invention is described above, and the refrigerant flow direction of the dual enhanced vapor injection refrigeration system and the control method of the dual enhanced vapor injection refrigeration system are described below.

The outdoor temperature is smaller than a preset temperature value, the first auxiliary road superheat degree is larger than a second specified threshold value, and the second auxiliary road superheat degree falls into a specified superheat degree range, so that the first throttle valve EXV1, the second throttle valve EXV2 and the third throttle valve EXV3, the first auxiliary road electromagnetic valve SV1 and the second auxiliary road electromagnetic valve SV4 are controlled to be opened, and the first auxiliary road electromagnetic valve SV2 and the second auxiliary road electromagnetic valve SV3 are controlled to be closed.

The air conditioner enters a heating mode, working medium at the outlet of the compressor 1 enters the indoor heat exchanger 2 through the four-way valve 7, the working medium at the outlet of the indoor heat exchanger 2 sequentially passes through a second main path inlet, a second main path outlet and a third throttle valve EXV3 of the second auxiliary heat exchanger 63, a second auxiliary path inlet, a second auxiliary path outlet, a second auxiliary path bypass electromagnetic valve SV4 and the gas-liquid separator 4 of the second auxiliary heat exchanger 63, and finally returns to the compressor 1; the working medium at the outlet of the indoor heat exchanger 2 flows out through the second main path outlet, then sequentially passes through the first main path inlet, the first main path outlet, the second throttle valve EXV2, the first auxiliary path inlet, the first auxiliary path outlet and the first auxiliary path electromagnetic valve SV1 of the first auxiliary heat exchanger 53, and finally enters the first auxiliary path air inlet 11; the working medium at the outlet of the first main path passes through a first throttling valve EXV1, an outdoor heat exchanger, a four-way valve, a gas-liquid separator 4 and finally returns to the compressor 1.

Referring to fig. 3 and 4, the control method includes the following steps:

s1: the air conditioner enters a heating mode to operate;

s2: controlling the opening degree of the first throttle valve EXV1 in accordance with the compressor discharge temperature; specifically, the initial opening degree of the first throttle valve EXV1 is 360 steps, and the minimum opening degree is 80 steps;

s3: judging whether the exhaust superheat degree is larger than a first specified threshold value or not, and executing step S4 if the exhaust superheat degree is larger than the first specified threshold value; otherwise, executing step S9;

s4: judging the relation between the outdoor temperature and the preset temperature interval and the preset temperature value, if the relation is in the preset temperature interval, entering the step S5, and if the outdoor temperature is less than or equal to the preset temperature value, entering the step S6;

s5: judging whether the first auxiliary road superheat degree of the first heat exchange auxiliary road is smaller than a second specified threshold value or not, if the first auxiliary road superheat degree is larger than the second specified threshold value or larger than a specified superheat degree high threshold value (such as 2 ℃), adjusting the opening degree of a second throttle valve according to the first auxiliary road superheat degree, and specifically, until the first auxiliary road superheat degree is maintained at the second specified threshold value, opening a first auxiliary road electromagnetic valve SV1, closing a first auxiliary road electromagnetic valve SV2 and keeping EXV3 closed; if the first degree of superheat of the auxiliary road is less than the second prescribed threshold, proceed directly to step S7;

s6: judging whether the first auxiliary road superheat degree of the first heat exchange auxiliary road is smaller than a second specified threshold value or not, if the first auxiliary road superheat degree is larger than the second specified threshold value or larger than a specified superheat degree high threshold value (such as 2 ℃), adjusting the opening degree of a second throttle valve according to the first auxiliary road superheat degree, and specifically, opening a first auxiliary road electromagnetic valve SV1 and closing a first auxiliary road bypass electromagnetic valve SV2 until the first auxiliary road superheat degree is maintained at the second specified threshold value; if the first degree of superheat of the auxiliary road is less than the second prescribed threshold, proceed directly to step S8; judging whether the second auxiliary road superheat degree of the second auxiliary road is smaller than a third specified threshold value or not, if the second auxiliary road superheat degree is larger than the third specified threshold value or larger than a specified superheat degree high threshold value (such as 2 ℃), controlling the opening degree of a third throttle valve according to the second auxiliary road superheat degree, and specifically, maintaining the second auxiliary road superheat degree at the third specified threshold value; if the second degree of bypass superheat is less than the third prescribed threshold, the routine proceeds to step S8:

s7: if the first auxiliary road superheat degree is in a specified superheat degree range (0.5-1 ℃), adjusting the opening degree of the second throttle valve EXV2 to a preset opening degree (step 108), keeping the first auxiliary road electromagnetic valve SV1 closed, keeping the first auxiliary road bypass electromagnetic valve SV2 open until step S5 is met, and if the auxiliary road superheat degree is less than a specified superheat degree low threshold value (step 0.5 ℃), keeping the second throttle valve EXV2, the first auxiliary road electromagnetic valve SV1 and the first auxiliary road bypass electromagnetic valve SV2 closed;

s8: if the first auxiliary road superheat degree is in a specified superheat degree range (0.5-1 ℃), adjusting the opening degree of the second throttle valve EXV2 to a preset opening degree (step 108), keeping the first auxiliary road electromagnetic valve SV1 closed, keeping the first auxiliary road bypass electromagnetic valve SV2 open until step S6 is met, and if the auxiliary road superheat degree is less than a specified superheat degree low threshold value (step 0.5 ℃), keeping the second throttle valve EXV2, the first auxiliary road electromagnetic valve SV1 and the first auxiliary road bypass electromagnetic valve SV2 closed;

if the second auxiliary road superheat degree is in a specified superheat degree range (0.5-1 ℃), adjusting the opening degree of the third throttle valve EXV3 to a preset opening degree (step 108), keeping the second auxiliary road electromagnetic valve SV3 closed, keeping the second auxiliary road bypass electromagnetic valve SV4 open until step S6 is met, and if the auxiliary road superheat degree is less than a specified superheat degree low threshold value (step 0.5 ℃), keeping the second throttle valve EXV3, the second auxiliary road electromagnetic valve SV3 and the second auxiliary road bypass electromagnetic valve SV4 closed;

s9: the second throttle valve EXV2, the third throttle valve EXV3 are closed until step S3 is satisfied.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.