CN116465114A - Heat pump system with multiple heat exchangers and refrigerant quantity dynamic balance control method thereof - Google Patents

Abstract

The application relates to the technical field of heat pump system machinery, in particular to a high-efficiency heat pump unit system with multiple heat exchangers and a refrigerant quantity dynamic balance control technology. The heat pump system comprises a compressor and at least three heat exchangers, one of the heat exchangers always participates in circulation operation, the rest heat exchangers are heat exchangers participating in circulation and/or heat exchangers which are idle, and the controller judges the circulation quantity of the refrigerant of the system according to the following conditions, namely the liquid level height in the first liquid storage device, the second exhaust superheat degree and the third liquid pipe supercooling degree; when the first condition is lower than the set value and the second condition is higher than the set value, or the first condition and the third condition are both lower than the set value, judging that the circulation quantity of the refrigerant of the system is insufficient, and guiding the refrigerant in the heat exchanger in an idle state into the suction inlet of the compressor; when the first condition is higher than the set value and the second condition is lower than the set value, or the first condition and the third condition are both higher than the set value, the circulation quantity of the system refrigerant is excessive, and the high-pressure refrigerant in the liquid reservoir is led into the heat exchanger in an idle state.

Description

Heat pump system with multiple heat exchangers and refrigerant quantity dynamic balance control method thereof

Technical Field

The application relates to the technical field of heat pump system machinery, in particular to a high-efficiency heat pump unit system with multiple heat exchangers and a refrigerant quantity dynamic balance control technology.

Background

The heat absorbed by the air-cooled heat pump in summer and the condensation heat obtained by the power consumption of the compressor are directly discharged to the outdoor air through the fin coil, and the heat absorbed by the fin coil from the outdoor air and the condensation heat obtained by the power consumption of the compressor are discharged to the air-cooled hot water when the air-cooled heat pump is used for heating in winter. Therefore, the air-cooled heat pump has both the functions of cooling in summer and heating in winter, and is widely applied to the central air-conditioning engineering project of the cold-warm type building with the requirements of cooling in summer and heating in winter.

When the air-cooled heat pump is used for refrigerating in summer, the air temperature difference between the inlet air and the outlet air of the air-cooled fin coil is large because the density and the specific heat capacity of air are small; meanwhile, because the air heat transfer coefficient is lower, the heat transfer temperature difference between the high-pressure refrigerant of the air-cooled fin coil and the outdoor air is larger; the two factors lead to higher condensation temperature in summer refrigeration of the air-cooled heat pump, and the refrigeration energy efficiency of the unit is usually only 2.6-3.0. For summer, winter, cold and summer, winter and warm areas, the cooling season time in summer is as long as 3-8 months, the heating season time in winter is generally only 1-2 months, and the heating load is generally less than 60% of the cooling load, so that the cooling energy efficiency is a key index for influencing the annual air conditioner running cost and annual building energy consumption, and for summer, winter, cold, summer, hot and winter areas, the air-cooled heat pump is obviously not an ideal cooling and heating heat pump host.

In order to improve the refrigeration energy efficiency of the cold-hot type heat pump host, the prior art improves the type of a condenser in the refrigeration operation in summer based on the traditional air-cooled heat pump, and sequentially pushes out the high-efficiency cold-hot type heat pump host such as a steam-cooled heat pump, a compound double-cold-source heat pump and the like. The applicant has also made extensive developments on the above new models in the early stage, for example from the prior application published under number: CN113446755B, name: double-source integrated air source heat pump unit with total heat recovery function; for example, the prior application publication No.: CN113446754B, name: a double-cold-source air source heat pump unit with total heat recovery.

The evaporative cooling and heating pump unit is characterized in that an evaporative condenser is added on the basis of a traditional air-cooled heat pump, the evaporative condenser is used for replacing an air-cooled fin coil pipe during refrigeration in summer, the condensation heat of high-pressure refrigerant is absorbed through phase-change evaporation of circulating water of the evaporative condenser, and water vapor is taken away by outdoor air flowing through the evaporative condenser. The composite double-cold-source heat pump is provided with a water-cooling condenser and a cooling tower on the basis of the traditional air-cooling heat pump, the water-cooling condenser is used for replacing an air-cooling fin coil pipe during refrigeration in summer, and the cooling water is used as an intermediate heat exchange link to realize the discharge of condensation heat of high-pressure refrigerant to outdoor air flowing through the cooling tower. Compared with the air-cooled condensing technology of the fin coil pipe with the characteristic of dry cooling, the evaporative condensing technology adopted by the evaporative cooling and heating pump and the water-cooled condensing technology adopted by the composite double-cold-source heat pump are wet cooling, so that the heat exchange efficiency of the condenser can be greatly improved, the condensing temperature of a unit is obviously reduced, and the refrigerating operation energy efficiency is improved. Meanwhile, the operation mechanism of the evaporative cold heat pump and the composite double-cold-source heat pump during heating in winter is completely the same as that of a conventional air-cooled heat pump, a fin coil is used as an evaporator to extract heat from outdoor air, and the condensation heat of the high-pressure refrigerant is finally discharged to air-conditioning hot water flowing through a use side heat exchanger through the work of a compressor.

In summary, on the basis of the use side heat exchanger and the fin coil of the traditional air-cooled heat pump, the novel cooling and heating type efficient heat pump unit is additionally provided with the evaporative condenser or the water-cooled condenser, so that the unit has three heat exchangers, two heat exchangers are used as evaporators or condensers to participate in the circulation operation no matter in a refrigeration mode or a heating mode, the use side heat exchanger always participates in the circulation operation, and meanwhile, one heat exchanger does not participate in the circulation operation but is in an idle state in each mode.

The quantity of the refrigerant required by the cooling and heating modes of the cooling and heating type heat pump unit is often greatly different, and the quantity of the refrigerant required by the influence of working conditions and loads is actually dynamically changed even in the same mode; meanwhile, when the unit is stopped or the mode is switched, part of the refrigerant is often stored in the idle heat exchanger. When the quantity of the refrigerant stored in the idle heat exchanger is too large, namely the quantity of the actual refrigerant participating in the circulating operation of the system is small, and the quantity of the refrigerant required by the current running mode and working condition of the unit is large, the quantity of the refrigerant of the circulating operation system of the unit is insufficient and the low pressure is too low, so that the refrigerating capacity and the refrigerating energy efficiency of the unit are attenuated, and when the quantity of the refrigerant is severe, the high-temperature or low-pressure switch of the compressor is tripped. On the contrary, when the quantity of the refrigerant stored in the idle heat exchanger is small, namely the quantity of the actual refrigerant participating in the circulation operation of the system is large, and the quantity of the refrigerant actually required under the current operation mode and working condition of the unit is small, the quantity of the refrigerant of the circulation operation system of the unit is too high, so that the high pressure of the unit is too high, the refrigerating capacity and the refrigerating energy efficiency of the unit are also attenuated, and the motor of the unit is overloaded even the compressor is caused to operate with liquid to influence the reliability.

Disclosure of Invention

In order to solve the problems that when the high-efficiency heat pump host machines such as the evaporative cold heat pump, the compound double-cold source heat pump and the like adopt more than three heat exchangers, the quantity of refrigerant in the system circulation operation is too high or too low to cause the unit operation to be too high or too low to cause the performance attenuation and the reliability reduction of the unit in different operation modes, the application provides a heat pump system with multiple heat exchangers and a refrigerant quantity dynamic balance control technology thereof, and the technology solves the problems that the quantity of refrigerant in the system circulation operation is too high or too low when the cold-warm heat pump host machine is configured to operate with multiple heat exchangers, and improves the performance and the reliability of the unit.

In one aspect, the application provides a heat pump system with multiple heat exchangers, which comprises a compressor 4, a four-way valve 19, an air side finned coil 18, an evaporative condenser 17, a liquid storage device 1, a throttle valve 22, a water side heat exchanger 20 and a gas-liquid separator 14 which are sequentially connected in a circulation loop, wherein a high-pressure exhaust port of the compressor 4 is connected with a four-way valve 19 interface d, a four-way valve 19 interface c is connected with the air side finned coil 18, a four-way valve 19 interface s is connected with an inlet of the gas-liquid separator 14, an outlet of the gas-liquid separator 14 is connected with a low-pressure air suction port of the compressor 4, and a four-way valve 19 interface e is connected with the water side heat exchanger 20; a twenty-first valve 21 is arranged in a communication channel between the liquid side header port 181 of the air side fin coil 18 and the air side port of the evaporative condenser 17, a twelfth valve 12 is also arranged in a communication pipeline between the liquid side port of the evaporative condenser 17 and the liquid side heat exchanger 1, a fifteenth valve 15 is arranged between the throttle valve 22 and the water side heat exchanger 20, a sixteenth valve 16 is arranged in a communication pipeline between the liquid side distributing head 182 of the air side fin coil 18 and the throttle valve 22 and the fifteenth valve 15, a thirteenth valve 13 is arranged in a communication pipeline between the twelfth valve 12 and the liquid side heat exchanger 1 and between the fifteenth valve 15 and the water side heat exchanger 20, a connection port s between the evaporative condenser 17 and the twelfth valve 12 and the four-way valve 19 and the gas-liquid separator 14 are mutually connected, and a connection is also arranged between the evaporative condenser 17 and the twelfth valve 12 and the liquid side heat exchanger 1 and the throttle valve 22.

In particular, a seventh valve 7 is disposed in a connecting pipeline between the evaporative condenser 17 and the twelfth valve 12 and the four-way valve 19 and the gas-liquid separator 14, and a fifth valve 5 is disposed in a connecting pipeline between the evaporative condenser 17 and the twelfth valve 12 and the liquid reservoir 1 and the throttle valve 22.

In particular, the twenty-first valve 21 is an electrically operated valve, and the seventh valve 7 and the fifth valve 5 are solenoid valves.

In particular, the twelfth, thirteenth, fifteenth and sixteenth valves 12, 13, 15, 16 are one-way valves, i.e. the twelfth valve 12 controls the evaporative condenser 17 to the reservoir 1, the thirteenth valve 13 controls the water side heat exchanger 20 to the reservoir 1, the fifteenth valve 15 controls the throttle valve 22 to the water side heat exchanger 20, and the sixteenth valve 16 controls the throttle valve 22 to the liquid side distribution head 182 of the air side fin coil 18.

In particular, a level sensor is provided in the reservoir 1.

In particular, the liquid level sensor is selected from a capacitive liquid level sensor, a magnetostrictive liquid level sensor or a multi-stage liquid level switch which outputs an analog signal.

In particular, the system also includes a controller that collects signals from the compressor and the level sensor and issues commands to control the opening and closing of the valves.

Particularly, when the heat pump unit operates under a refrigerating condition, the compressor 4 discharges high-temperature and high-pressure refrigerant gas, and then sequentially passes through the four-way valve 19, the air side fin coil 18, the evaporative condenser 17, the twelfth valve 12, the liquid storage 1, the throttle valve 22, the fifteenth valve 15, the water side heat exchanger 20 and the four-way valve 19, and finally returns to the compressor 4 through the gas-liquid separator 14; when the heat pump unit adopts a heating worker Kuang Yun, the twenty-first valve 21 is closed, the four-way valve 19 is electrified, the compressor 4 discharges high-temperature and high-pressure refrigerant gas, and then the refrigerant gas sequentially passes through the four-way valve 19, the water side heat exchanger 20, the thirteenth valve 13, the liquid storage device 1, the throttle valve 22, the sixteenth valve 16, the air side fin coil 18 and the four-way valve 19, and finally returns to the compressor 4 through the gas-liquid separator 14, and the evaporative condenser 17 is isolated outside an operation system to form an empty heat exchanger during heating; the controller judges the quantity of the refrigerant circulation quantity through three conditions, namely a first condition and the liquid level height in the liquid reservoir; second, exhausting superheat degree; thirdly, supercooling degree of the liquid pipe; when the first condition is lower than the set value and the second condition is higher than the set value, or the first condition and the third condition are both lower than the set value, the system refrigerant circulation quantity is judged to be insufficient, and at the moment, the controller controls the refrigerant in the evaporative condenser 17 in an idle state to be led into the suction inlet of the compressor 4; when the first condition is higher than the set value and the second condition is lower than the set value, or the first condition and the third condition are both higher than the set value, the circulation amount of the refrigerant in the system is excessive, and at the moment, the controller controls the high-pressure refrigerant in the liquid reservoir 1 to be led into the evaporative condenser 17 in an idle state for temporary storage.

On the other hand, the application also provides a refrigerant quantity dynamic balance control method of the heat pump system with a plurality of heat exchangers, wherein the heat pump system comprises a compressor, at least three heat exchangers and a liquid reservoir and forms a circulation loop, and further comprises a controller for receiving signals and sending control instructions, one of the heat exchangers is a use side heat exchanger which always participates in the circulation operation of the system, the rest heat exchangers are divided into heat exchangers which participate in the circulation of the system and/or heat exchangers which are in idle states according to different functional modes, and the judgment basis of the refrigerant circulation quantity of the system comprises the liquid level height in the first-condition liquid reservoir, the second-condition exhaust superheat degree and the third-condition liquid tube supercooling degree; when the first condition is lower than the set value and the second condition is higher than the set value, or the first condition and the third condition are both lower than the set value, the system refrigerant circulation quantity is judged to be insufficient, and at the moment, the controller controls the refrigerant in the heat exchanger in the idle state to be led into the suction inlet of the compressor; when the first condition is higher than the set value and the second condition is lower than the set value, or the first condition and the third condition are both higher than the set value, the circulation quantity of the system refrigerant is excessive, and at the moment, the controller controls the high-pressure refrigerant in the liquid reservoir to be led into the heat exchanger in the idle state for temporary storage.

In particular, the level of the liquid in the reservoir is monitored by a liquid level sensor; the exhaust superheat degree is calculated by the exhaust temperature monitored by an exhaust temperature sensor and the exhaust pressure monitored by an exhaust pressure sensor; the liquid pipe supercooling degree is calculated by the liquid pipe temperature and the exhaust pressure monitored by the liquid pipe temperature sensor; the controller judges and sends out control instructions according to the liquid level height, the exhaust superheat degree and the liquid pipe supercooling degree in the liquid storage device.

On the basis of the common sense in the art, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the application.

The technical scheme has the following advantages or beneficial effects: according to the heat pump system with the multiple heat exchangers and the refrigerant quantity dynamic balance control technology thereof, the refrigerant quantity in the system can be accurately regulated when the heat pump unit with the multiple heat exchangers operates, the condition that the refrigerant quantity of the system circularly operates is too high or too low is avoided, and therefore the performance and reliability of the unit are improved; by adopting the control method, the heat pump system with multiple heat exchangers can stably and efficiently operate, so that the introduction of the evaporation-cooled condenser, the water-cooled condenser, the flooded evaporator, the falling film evaporator and other efficient heat exchangers into the heat pump system is possible, the energy efficiency of the heat pump system is greatly improved, and the operation cost of a unit is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It will be obvious to a person skilled in the art that other figures can be obtained from the figures provided without the inventive effort.

Fig. 1 is a schematic diagram of a principle of a dynamic balance control technique for a refrigerant amount of a heat pump system according to an embodiment of the present application.

FIG. 2 is a heat pump system with multiple heat exchangers according to one embodiment of the present application.

Wherein, 1-the reservoir; 4-compressors; 5-a fifth valve; 7-seventh valve; 12-twelfth valve; 13-thirteenth valve; 14-a gas-liquid separator; 15-fifteenth valve; 16-sixteenth valve; 17-evaporative condenser; 18-air side fin coil; 19-a four-way valve; 20-water side heat exchanger; 21-twenty-first valve; 22-throttle valve.

Detailed Description

The technical solutions in the embodiments of the present application are clearly and completely described below with reference to the drawings of the present application. It is apparent that the described embodiments are only some of the embodiments of the present application and are intended to be used to explain the inventive concept. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, are intended to be within the scope of the present application.

The terms "first," "second," and the like, as used in the description, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. The term "plurality" means two or more, unless specifically defined otherwise.

The terms "coupled," "connected," and the like as used in the description herein are to be construed broadly and may be, for example, fixedly coupled, detachably coupled, or integrally formed, unless otherwise specifically defined and limited; may be a mechanical connection, an electrical connection; can be directly connected and indirectly connected through an intermediate medium; may be a communication between two elements or an interaction between two elements. The specific meaning of the terms in the embodiments can be understood by those of ordinary skill in the art according to the specific circumstances.

The terms "one particular embodiment" and "one particular embodiment" as used in this description mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

The heat pump system comprises a compressor, at least three heat exchangers and a liquid reservoir, and also comprises a controller for receiving signals and sending control instructions, wherein one of the heat exchangers is a heat exchanger at the use side which always participates in the circulation operation of the system, the rest heat exchangers are divided into heat exchangers which participate in the circulation of the system and/or heat exchangers in an idle state according to different functional modes, and the judgment basis of the quantity of the refrigerant circulation of the system comprises: the method comprises the following steps that firstly, the liquid level in a liquid reservoir is monitored by a liquid level sensor; the second condition is the degree of superheat of the exhaust gas, wherein the degree of superheat of the exhaust gas is calculated by the exhaust gas temperature monitored by an exhaust gas temperature sensor and the exhaust gas pressure monitored by an exhaust gas pressure sensor; thirdly, the supercooling degree of the liquid pipe is calculated by the temperature of the liquid pipe and the exhaust pressure monitored by a liquid pipe temperature sensor; when the first condition is lower than the set value and the second condition is higher than the set value, or the first condition and the third condition are both lower than the set value, the system refrigerant circulation quantity is judged to be insufficient, and at the moment, the controller controls the refrigerant in the heat exchanger in the idle state to be led into the suction inlet of the compressor; when the first condition is higher than the set value and the second condition is lower than the set value, or the first condition and the third condition are both higher than the set value, the circulation quantity of the system refrigerant is excessive, and at the moment, the controller controls the high-pressure refrigerant in the liquid reservoir to be led into the heat exchanger in the idle state for temporary storage.

Referring to fig. 1, one embodiment of the present application provides a heat pump system with multiple heat exchangers and a refrigerant quantity dynamic balance control technology thereof, which includes a liquid reservoir with a liquid level sensor, a first heat exchanger, a second heat exchanger, a compressor, a fifth control valve, a sixth control valve, a seventh control valve, an eighth control valve, a controller and a using side heat exchanger which are connected in a refrigeration cycle loop, not shown. The liquid reservoir is sequentially communicated with the fifth control valve and the first heat exchanger through the refrigerant pipeline, and is sequentially communicated with the sixth control valve and the second heat exchanger through the other refrigerant pipeline. The first heat exchanger is connected with a suction inlet of the compressor through a refrigerant pipeline in sequence; and the heat exchanger is sequentially connected with the eighth control valve and the suction inlet of the compressor through the refrigerant pipeline. The controller is respectively connected with the fifth control valve, the sixth control valve, the seventh control valve, the eighth control valve, the compressor and a liquid level sensor arranged in the liquid reservoir through control cables.

The heat pump unit has multiple functional modes, including three heat exchangers including a first heat exchanger, a second heat exchanger and a using side heat exchanger. The number of the heat exchangers in each functional mode participating in the system circulation operation is two, and the number of the heat exchangers in the use side is one, and the heat exchangers in the idle state participate in the system circulation operation all the time. Of course, the number of the heat exchangers in the idle state can be two or more, and the total number of the heat exchangers of the unit is correspondingly increased.

In the refrigeration mode, the side heat exchanger is used as an evaporator to participate in the circulation operation so as to generate the chilled water of the air conditioner. In the heating mode, the side heat exchanger is used as a condenser to participate in the circulating operation of the system so as to generate air-conditioning hot water. And according to different functional modes, one heat exchanger participates in the circulating operation of the system, and the other heat exchanger is in an idle state.

The controller detects the refrigerant level thereof by a level sensor disposed on the accumulator. The liquid level sensor in the liquid reservoir can be a capacitive liquid level sensor, a magnetostrictive liquid level sensor and a multi-section liquid level switch which output analog signals.

When the circulation quantity of the system refrigerant is insufficient, the controller conducts the seventh control valve or the eighth control valve to guide the refrigerant in the first heat exchanger or the second heat exchanger in an idle state into the suction inlet of the compressor, so that the refrigerant in the idle heat exchanger is guided into the whole circulation operation system to avoid the deficiency of the refrigerating capacity. When the circulation quantity of the refrigerant in the system is judged to be excessive, the controller conducts the fifth control valve and the sixth control valve, and high-pressure liquid in the liquid reservoir is led into the first heat exchanger or the second heat exchanger which are in an idle state, so that redundant refrigerant of a circulating operation system of the unit is temporarily stored in the idle heat exchanger.

The first heat exchanger and the second heat exchanger can adopt common heat exchangers, such as an evaporative condenser, a finned coil, a total heat recoverer, a water-cooled condenser and other forms.

Referring to fig. 2, a specific embodiment of the present application proposes a heat pump system with multiple heat exchangers and a refrigerant quantity dynamic balance control technology thereof, wherein the first heat exchanger and the second heat exchanger of the heat pump system respectively adopt an evaporative condenser 17 and an air side fin coil 18. Specifically, the heat pump system with multiple heat exchangers comprises a compressor 4, a four-way valve 19, an air side fin coil 18, an evaporative condenser 17, a liquid reservoir 1, a throttle valve 22, a water side heat exchanger 20 and a gas-liquid separator 14 which are sequentially connected in a circulation loop, wherein a high-pressure exhaust port of the compressor 4 is connected with a four-way valve 19 interface d, a four-way valve 19 interface c is connected with the air side fin coil 18, a four-way valve 19 interface s is connected with an inlet of the gas-liquid separator 14, an outlet of the gas-liquid separator 14 is connected with a low-pressure air suction port of the compressor 4, and a four-way valve 19 interface e is connected with the water side heat exchanger 20; a twenty-first valve 21 is arranged in a communication channel between the liquid side header port 181 of the air side fin coil 18 and the air side port of the evaporative condenser 17, a twelfth valve 12 is also arranged in a communication pipeline between the liquid side port of the evaporative condenser 17 and the liquid side heat exchanger 1, a fifteenth valve 15 is arranged between the throttle valve 22 and the water side heat exchanger 20, a sixteenth valve 16 is arranged in a communication pipeline between the liquid side distributing head 182 of the air side fin coil 18 and the throttle valve 22 and the fifteenth valve 15, a thirteenth valve 13 is arranged in a communication pipeline between the twelfth valve 12 and the liquid side heat exchanger 1 and between the fifteenth valve 15 and the water side heat exchanger 20, a connection port s between the evaporative condenser 17 and the twelfth valve 12 and the four-way valve 19 and the gas-liquid separator 14 are mutually connected, and a connection is also arranged between the evaporative condenser 17 and the twelfth valve 12 and the liquid side heat exchanger 1 and the throttle valve 22. A seventh valve 7 is arranged in a connecting pipeline between the evaporative condenser 17 and the twelfth valve 12 and the interface s of the four-way valve 19 and the gas-liquid separator 14, and a fifth valve 5 is arranged in a connecting pipeline between the evaporative condenser 17 and the twelfth valve 12 and the liquid reservoir 1 and the throttle valve 22.

Preferably, the twenty-first valve 21 is an electric valve, and the seventh valve 7 and the fifth valve 5 are electromagnetic valves. The twelfth valve 12, the thirteenth valve 13, the fifteenth valve 15 and the sixteenth valve 16 are one-way valves, namely the twelfth valve 12 controls the evaporative condenser 17 to be communicated with the liquid storage 1, the thirteenth valve 13 controls the water side heat exchanger 20 to be communicated with the liquid storage 1, the fifteenth valve 15 controls the throttle valve 22 to be communicated with the water side heat exchanger 20, and the sixteenth valve 16 controls the throttle valve 22 to be communicated with the liquid side distributing head 182 of the air side fin coil 18.

The liquid accumulator 1 is provided with a liquid level sensor, and the liquid level sensor is selected from a capacitive liquid level sensor, a magnetostrictive liquid level sensor or a multi-stage liquid level switch which outputs analog signals. The system also comprises a controller, wherein the controller collects signals of the compressor and the liquid level sensor and sends out instructions for controlling the switch of each valve.

The working flow of the refrigerant of the cold and hot pump unit is as follows: when the heat pump unit operates under a refrigerating condition, the compressor 4 discharges high-temperature and high-pressure refrigerant gas, and then sequentially passes through the four-way valve 19, the air side fin coil 18, the electric valve 21, the evaporative condenser 17, the twelfth valve 12, the liquid storage 1, the throttle valve 22, the fifteenth valve 15, the water side heat exchanger 20 and the four-way valve 19, and finally returns to the compressor 4 through the gas-liquid separator 14.

When the heat pump unit adopts a heating process Kuang Yun, the twenty-first valve 21 is closed, the four-way valve 19 is electrified, the compressor 4 discharges high-temperature and high-pressure refrigerant gas, and then the refrigerant gas sequentially passes through the four-way valve 19, the water side heat exchanger 20, the thirteenth valve 13, the liquid storage device 1, the throttle valve 22, the sixteenth valve 16, the air side fin coil 18 and the four-way valve 19, and finally returns to the compressor 4 through the gas-liquid separator 14. Wherein the fifth valve 5, the seventh valve 7, the twenty-first valve 21 and the twelfth valve 12 are in a closed state, and the evaporative condenser 17 is isolated outside the operation system to form an empty heat exchanger.

The controller controls the liquid level in the liquid reservoir according to three conditions, namely, a first condition; second, exhausting superheat degree; thirdly, supercooling degree of the liquid pipe; when the first condition is lower than the set value and the second condition is higher than the set value, or the first condition and the third condition are lower than the set value, the system refrigerant circulation quantity is judged to be insufficient; and when the first condition is higher than the set value and the second condition is lower than the set value, or the first condition and the third condition are both higher than the set value, the system refrigerant circulation quantity is excessive. When the circulation amount of the system refrigerant is insufficient, the controller controls the seventh valve 7 to be electrified, and the refrigerant liquid stored in the evaporative condenser 17 is led into the low-pressure pipeline in front of the gas-liquid separator 14, so that the refrigerant is led into the whole operation system to compensate the deficiency. When the circulation amount of the refrigerant in the system is excessive, the controller controls the fifth valve 5 to be electrified, and the refrigerant in the liquid reservoir 1 is led into the evaporative condenser 17, so that the redundant refrigerant of the whole operation system is led into the empty evaporative condenser 17 for temporary storage.

While embodiments of the present application have been illustrated and described above, it will be appreciated that the above-described embodiments are exemplary and should not be construed as limiting the present application. Various changes and modifications may be made to the present application without departing from the spirit and scope of the application, and such changes and modifications fall within the scope of the application as hereinafter claimed.

Claims (10)

1. The heat pump system with the multiple heat exchangers comprises a compressor (4), a four-way valve (19), an air side fin coil pipe (18), an evaporative condenser (17), a liquid reservoir (1), a throttle valve (22), a water side heat exchanger (20) and a gas-liquid separator (14) which are sequentially connected in a circulation loop, wherein a high-pressure exhaust port of the compressor (4) is connected with a four-way valve (19) interface d, a four-way valve (19) interface c is connected with the air side fin coil pipe (18), a four-way valve (19) interface s is connected with an inlet of the gas-liquid separator (14), an outlet of the gas-liquid separator (14) is connected with a low-pressure air suction port of the compressor (4), and a four-way valve (19) interface e is connected with the water side heat exchanger (20); a twenty-first valve (21) is arranged in a communication channel between a liquid side header connector (181) of the air side fin coil pipe (18) and an air side connector of the evaporative condenser (17), and is characterized in that: a twelfth valve (12) is further arranged in a communication pipeline between a liquid side interface of the evaporative condenser (17) and the liquid storage device (1), a fifteenth valve (15) is arranged between the throttle valve (22) and the water side heat exchanger (20), a sixteenth valve (16) is arranged in a pipeline between a liquid side distribution head (182) of the air side fin coil pipe (18) and the throttle valve (22) and the fifteenth valve (15), a thirteenth valve (13) is arranged in a communication pipeline between the twelfth valve (12) and the liquid storage device (1) and between the fifteenth valve (15) and the water side heat exchanger (20), an interface s between the evaporative condenser (17) and the twelfth valve (12) and the four-way valve (19) and the gas-liquid separator (14) are connected with each other, and a space between the evaporative condenser (17) and the twelfth valve (12) and the liquid storage device (1) and the throttle valve (22) are also connected with each other.

2. The heat pump system with multiple heat exchangers according to claim 1, wherein a seventh valve (7) is arranged in a connecting pipeline between the evaporation condenser (17) and the twelfth valve (12) and the four-way valve (19) interface s and the gas-liquid separator (14), and a fifth valve (5) is arranged in a connecting pipeline between the evaporation condenser (17) and the twelfth valve (12) and between the liquid reservoir (1) and the throttle valve (22).

3. A heat pump system with multiple heat exchangers according to claim 1 or 2, wherein the twenty-first valve (21) is an electric valve and the seventh valve (7) and the fifth valve (5) are solenoid valves.

4. The heat pump system with multiple heat exchangers according to claim 1 or 2, wherein the twelfth valve (12), thirteenth valve (13), fifteenth valve (15), sixteenth valve (16) are one-way valves, i.e. the twelfth valve (12) controls the evaporative condenser (17) to the reservoir (1), the thirteenth valve (13) controls the water side heat exchanger (20) to the reservoir (1), the fifteenth valve (15) controls the throttle valve (22) to the water side heat exchanger (20), the sixteenth valve (16) controls the throttle valve (22) to the liquid side distribution head (182) of the air side fin coil (18).

5. A heat pump system with multiple heat exchangers according to claim 1, wherein a liquid level sensor is provided in the reservoir (1).

6. The heat pump system with multiple heat exchangers according to claim 5, wherein the liquid level sensor is selected from a capacitive liquid level sensor outputting an analog signal, a magnetostrictive liquid level sensor, and a multi-stage liquid level switch.

7. The heat pump system with multiple heat exchangers according to claim 5, wherein the system further comprises a controller that collects signals from the compressor and the level sensor and issues commands to control the switches of the valves.

8. The heat pump system with multiple heat exchangers according to claim 7, wherein: when the heat pump unit operates under a refrigerating condition, the compressor (4) discharges high-temperature high-pressure refrigerant gas, and then sequentially passes through the four-way valve (19), the air side fin coil pipe (18), the evaporative condenser (17), the twelfth valve (12), the liquid storage device (1), the throttle valve (22), the fifteenth valve (15), the water side heat exchanger (20) and the four-way valve (19), and finally returns to the compressor (4) through the gas-liquid separator (14); when the heat pump unit adopts a heating worker Kuang Yun, a twenty-first valve (21) is closed, the four-way valve (19) is electrified, the compressor (4) discharges high-temperature and high-pressure refrigerant gas, and then the refrigerant gas sequentially passes through the four-way valve (19), the water side heat exchanger (20), a thirteenth valve (13), the liquid storage device (1), the throttle valve (22), a sixteenth valve (16), the air side fin coil pipe (18) and the four-way valve (19), and finally returns to the compressor (4) through the gas-liquid separator (14), and the evaporative condenser (17) is isolated outside an operation system to form an empty heat exchanger during heating; the controller judges the quantity of the refrigerant circulation quantity through three conditions, namely a first condition and the liquid level height in the liquid reservoir; second, exhausting superheat degree; thirdly, supercooling degree of the liquid pipe; when the first condition is lower than the set value and the second condition is higher than the set value, or the first condition and the third condition are both lower than the set value, the system refrigerant circulation quantity is judged to be insufficient, and at the moment, the controller controls the refrigerant in the evaporative condenser (17) in an idle state to be led into the suction inlet of the compressor (4); when the first condition is higher than the set value and the second condition is lower than the set value, or the first condition and the third condition are both higher than the set value, the system refrigerant circulation quantity is excessive, and at the moment, the controller controls the high-pressure refrigerant in the liquid reservoir (1) to be led into the evaporative condenser (17) in an idle state for temporary storage.

9. The heat pump system comprises a compressor, at least three heat exchangers and a liquid reservoir, and also comprises a controller for receiving signals and sending control instructions, wherein one of the heat exchangers is a heat exchanger at the use side which always participates in the circulation operation of the system, and the rest heat exchangers are divided into heat exchangers which participate in the circulation of the system and/or heat exchangers in an idle state according to different functional modes, and the heat pump system is characterized in that: the judging basis of the refrigerant circulation quantity of the system comprises the liquid level height in the first liquid storage device, the second exhaust superheat degree and the third liquid pipe supercooling degree; when the first condition is lower than the set value and the second condition is higher than the set value, or the first condition and the third condition are both lower than the set value, the system refrigerant circulation quantity is judged to be insufficient, and at the moment, the controller controls the refrigerant in the heat exchanger in the idle state to be led into the suction inlet of the compressor; when the first condition is higher than the set value and the second condition is lower than the set value, or the first condition and the third condition are both higher than the set value, the circulation quantity of the system refrigerant is excessive, and at the moment, the controller controls the high-pressure refrigerant in the liquid reservoir to be led into the heat exchanger in the idle state for temporary storage.

10. The refrigerant quantity dynamic balance control method of a heat pump system with multiple heat exchangers according to claim 9, wherein: the liquid level in the liquid reservoir is monitored by a liquid level sensor; the exhaust superheat degree is calculated by the exhaust temperature monitored by an exhaust temperature sensor and the exhaust pressure monitored by an exhaust pressure sensor; the liquid pipe supercooling degree is calculated by the liquid pipe temperature and the exhaust pressure monitored by the liquid pipe temperature sensor; the controller judges and sends out control instructions according to the liquid level height, the exhaust superheat degree and the liquid pipe supercooling degree in the liquid storage device.