RU2426956C2 - Air conditioning system with use of heat pump and control method of above system - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: air conditioning system has four-way valve, heat exchanger and control, which are located indoors, control and heat exchanger, which are located outdoors, and which are connected in series to each other so that circuit is formed. Compressor steam-jet system includes compressor which has the first gas inlet hole, the second gas inlet hole and gas outlet hole. The first gas inlet hole is connected to four-way valve by means of gas-water separator. The second gas inlet hole is connected by means of bypass tube on which electrical expansion valve is located to indoor located control and outdoor located control. Gas outlet hole is connected to four-way valve. Indoor control is in-series connected by means of fluid tank to outdoor control. Bypass tube is located between indoor control and fluid tank and has the coil located inside fluid tank. Gas condition sensors are located at the first gas inlet hole, the second gas inlet hole and gas outlet hole. Depending on sensor readings the pressure of the second gas inlet hole of compressor is regulated so that volume of cooling agent jet can be maintained at optimum level.

EFFECT: higher heating capacity and efficiency of used energy at low ambient air.

8 cl, 3 dwg

Description

FIELD OF THE INVENTION

The present invention relates to an air conditioner using a heat pump with outdoor air as a heat source, and more particularly, to an air conditioning system using a heat pump having a good heating effect under operating conditions at an extremely low outdoor temperature, and a method for controlling such a system.

BACKGROUND OF THE INVENTION

Conventional air conditioners using a heat pump with outdoor air as the heat source currently available on the market significantly reduce heat output or cannot even be started at ultra-low outdoor temperatures, which is why air conditioners in the northern regions of China with cold climates using a heat pump with outside air as a heat source can only be used during transitional seasons, and after the onset of cold weather they are not able to respond s basic requirements for heating. It is known that traditional central heating in the north of China is mainly provided by burning coal or gas, which cannot meet the requirements of social development for energy saving, environmental protection and safety. In this regard, it is desirable to create an air conditioning system using a heat pump that can operate at extremely low temperatures, and replace traditional central heating in northern China.

Summary of the invention

The present invention is based on the task of overcoming the disadvantages of the prior art and the creation of an air conditioning system using a heat pump having a good heating effect in operating conditions at ultra-low outdoor temperatures, and a method for controlling such a system.

To solve the problem of the present invention proposed:

an air conditioning system using a heat pump, having a four-way valve, an indoor heat exchanger, an indoor controller, an outdoor controller and an outdoor heat exchanger that are connected in series to the circuit, while the air conditioning system using a heat pump further has a steam compressor system, which includes a compressor having a first gas inlet opening, a second a gas inlet and a gas outlet, wherein said first gas inlet through a gas and water separator is connected to said four-way valve, said second gas inlet through a bypass pipe on which an electronic expansion valve is located is connected to said in the room by the regulator and said outdoor controller, and said gas outlet is connected to said four-way valve; said indoor controller through a fluid reservoir is connected in series with said outdoor regulator, and said bypass pipe is located between said indoor regulator and said fluid reservoir; wherein said bypass pipe has a coil located inside said fluid reservoir.

Said compressor steam-jet system further has a first sensor located at the first gas inlet, a second sensor located at the second gas inlet, and a third sensor located at the gas outlet.

Between said liquid reservoir and said outdoor heat exchanger, a set of cooling coils is arranged.

Mentioned sensors are pressure sensors or temperature sensors.

A method for controlling said air conditioning system using a heat pump includes a method for controlling a steam compressor system, comprising the steps of:

stage 1: determine the state of the gas at the first gas inlet, the second gas inlet and the gas outlet, respectively, designated as S _lower , S _jet and S _upper ,

stage 2: depending on the state of the gas S _lower at the first gas inlet and the state of gas S _upper at the gas outlet, calculate the state of gas S _intermediate when said compressor is operating,

stage 3: depending on the relationship between S _intermediate , S _jet and the predetermined target difference state S _{target, the} degree of opening of the second gas inlet opening is controlled.

In step 1, the gas pressure is additionally determined at the first gas inlet, the second gas inlet and the compressor gas outlet, which are respectively designated as P _lower , P _jet and P _upper , and the temperature is calculated according to the relationship between pressure and temperature T _jet , corresponding to P _jet ,

, и согласно зависимости между давлением и температурой вычисляют соответствующую температуру T_intermediate,in step 2, an intermediate pressure P _{intermediate is} additionally calculated when said compressor is operating, wherein

, and according to the relationship between pressure and temperature, the corresponding temperature T _{intermediate is} calculated,

stage 3 further includes:

stage 30, which calculates the temperature difference ΔT _actuat , which corresponds to the difference in actual pressures between the intermediate pressure of the compressor and the pressure of the jet from the second compressor inlet for gas inlet, while ΔT _actual = T _jet -T _intermediate ,

step 31, in which the difference N of the degrees of opening of the second gas inlet opening is calculated depending on the difference in actual temperatures ΔT _actual and the temperature difference ΔT _target corresponding to a predetermined target temperature difference, wherein N = ΔT _target -ΔT _actual ,

stage 32, in which it is determined that the degree of actual opening of the second gas inlet is equal to the sum of the degree of its initial opening and the difference N of the degrees of opening.

In step 1, the gas temperature is additionally determined at the first gas inlet, the second gas inlet and the compressor gas outlet, which are respectively designated as T _lower , T _jet and T _upper , and pressures are calculated according to the relationship between pressure and temperature P _lower and P _upper , corresponding to T _lower and T _upper ,

, и согласно зависимости между давлением и температурой вычисляют соответствующую температуру T_intermediate,in step 2, an intermediate pressure P _{intermediate is} additionally calculated when said compressor is operating, wherein

, and according to the relationship between pressure and temperature, the corresponding temperature T _{intermediate is} calculated,

stage 3 further includes:

stage 30, which calculates the temperature difference ΔT _actual , which corresponds to the difference in actual pressures between the intermediate pressure of the compressor and the pressure of the jet from the second compressor inlet for gas inlet, while ΔT _actual = T _jet -T _intermediate ,

stage 31, in which the difference N of the degrees of opening of the second gas inlet opening is calculated depending on the difference in actual temperatures ΔT _acuial and the temperature difference ΔT _target corresponding to a predetermined target temperature difference, wherein N = ΔT _target -ΔT _actual ,

stage 32, in which it is determined that the degree of actual opening of the second gas inlet is equal to the sum of the degree of its initial opening and the difference N of the degrees of opening.

Unlike the prior art, the present invention employs a steam-jet system for injecting an intermediate pressure into the compressor of a gaseous refrigerant and regulating the pressure at the jet inlet (i.e. at the second gas inlet of the compressor) in order to keep the cooler jet volume at an optimal level. Under normal operating conditions, the present invention functions as a conventional air conditioning apparatus using a heat pump for cooling and heating; when the outside temperature drops significantly and the heat output decreases, the steam-jet system is activated, which pumps saturated vapor of the intermediate pressure refrigerant into the compressor, due to which the compressor provides double compression and increases the heat output and energy efficiency when the system is operating at a low outdoor temperature air, and significantly reduces the frequency and duration of defrosting.

Brief Description of the Drawings

1 is a schematic diagram of an air conditioning system using a heat pump according to a first embodiment of the present invention,

figure 2 shows the pressure-enthalpy curve during operation of the air conditioning system using a heat pump in heating mode,

3 is a schematic diagram of an air conditioning system using a heat pump according to a third embodiment of the present invention.

Detailed Description of Preferred Embodiments

Additional features and advantages of the present invention will become apparent from the following detailed description with reference to the attached drawings.

First Embodiment

Figure 1 shows a schematic diagram of an air conditioning system using a heat pump according to the first embodiment of the present invention, in which solid lines with arrow arrows indicate the flow direction of the refrigerant when the air conditioning system using the heat pump is in heating mode. As shown in figure 1, the air conditioning system using a heat pump has an indoor controller 20, an indoor heat exchanger 19, a four-way valve 13, an outdoor heat exchanger 14, an outdoor controller 15, a set of cooling coils 16 and a tank 17 for liquid, while the above components are connected in series by copper pipes and form a cooling and heating circuit. The outdoor controller 15 has a check valve and an electronic expansion valve that are installed in parallel. Said air conditioning system using a heat pump further has a steam compressor system that includes a compressor 11 having a first gas inlet 111, a second gas inlet 112 and a gas outlet 113, said gas outlet 113 being connected to said four-way valve 13, said first gas inlet 111 through a gas and water separator is connected to said four-way valve 13, and A different gas inlet 112 through a bypass pipe on which an electronic expansion valve 21 is arranged is connected to said indoor regulator 20 and said fluid reservoir 17, that is, connected to an outlet end of an indoor regulator 20. On said bypass pipe the coil 18 filled with absorbent material, which is located inside the fluid reservoir 17, and thereby the refrigerant added to the second opening of the compressor for gas inlet, can provide up to the heat exchange in the fluid reservoir 17, that is, only gas without any fluid is added to the compressor, which ensures high reliability of the compressor. Compressor 11 may be an advanced digital scroll steam jet compressor, and an indoor expansion valve 20 may be an electronic expansion valve.

The air conditioning system using a heat pump further has a steam jet control device including three sensors and said electronic expansion valve 21. In one embodiment, the three sensors are, respectively, low pressure sensor 201, high pressure sensor 202 and jet pressure sensor 203. A high pressure sensor 202 is located at the opening 113 of the gas compressor 11, a low pressure sensor 201 is located at the first gas inlet 11 of the compressor 11, a jet pressure sensor 203 is located at the second gas inlet 112 of the compressor 11, and an electronic expansion valve 21 is located on said bypass pipe. When the air conditioning system using the heat pump operates in a heating mode at a low temperature, the refrigerant flowing from the heat exchanger 19 located in the room is divided into two flows: one refrigerant stream passes through an electronic expansion valve 21 located on said bypass pipe, and a coil 18 located inside the fluid reservoir 17, and then enters the second hole 112 of the compressor 11 for gas inlet; another refrigerant stream enters directly into the liquid tank and passes through the cooling coil 16 of the outdoor heat exchanger and the auxiliary controller 15 and then enters the outdoor heat exchanger 14.

The principle of operation of the steam-jet system control device is as follows: the sensors located at the compressor inlet for gas and the compressor outlet for gas outlet determine the gas pressure at the compressor inlet and outlet, then, depending on the pressure changes at the compressor inlet and outlet, the degree of opening of the second hole is controlled for gas inlet with the aim of regulating the volume of the steam jet, while the stages are carried out at which:

1) the sensors determine the gas pressure, respectively, at the first compressor inlet for gas inlet, the second compressor inlet for gas inlet and the compressor inlet for gas, which is indicated, respectively, as P _lower , P _jet and P _upper ,

2) according to the relationship between pressure and temperature, the temperature T _jet corresponding to P _{jet is} calculated,

, и согласно зависимости между давлением и температурой вычисляют соответствующую температуру T_intermediate,3) calculate the intermediate pressure P _intermediate when said compressor is running, while

, and according to the relationship between pressure and temperature, the corresponding temperature T _{intermediate is} calculated,

4) calculate the temperature difference ΔT _actual , which corresponds to the difference in actual pressures between the intermediate pressure of the compressor and the pressure of the jet from the second compressor inlet for gas inlet, while ΔT _actual = T _jet -T _intermediate ,

5) calculate the difference N of the degrees of opening of the second gas inlet opening, wherein N = ΔT _target -ΔT _actual , where ΔT _target means the temperature difference corresponding to the predetermined target temperature difference,

6) determine the degree of actual opening of the second gas inlet opening equal to the sum of the degree of its initial opening and the difference N of the degrees of opening.

In this embodiment, the opening degree of the second gas inlet is controlled by changing the opening degree of the electronic expansion valve 21. In this case, in step (5), the difference in the opening degrees of the electronic expansion valve 21 is N = ΔT _target -ΔT _actual ; at the stage (6), the degree of actual opening of the electronic expansion valve 21 is equal to the sum of the degree of its initial opening and the difference N of the degrees of opening.

Next, with reference to figure 2 describes the operation of the air conditioning system using a heat pump. When the system operates in heating mode at a low outdoor temperature, a low-temperature gaseous refrigerant under low pressure (peak 1) is supplied from an outdoor heat exchanger 14, compressed in compressor 11 to reach peak 2 of intermediate pressure, and then mixed in a scroll coil of compressor 11 with intermediate pressure gas (top 9), sucked from the second compressor inlet 112 for gas inlet, to reach peak 10, and then subjected to continuous compression in the compressor 11 in order to obtain a high-temperature high-pressure gas (peak 3); the high-temperature gaseous high-pressure refrigerant in the indoor heat exchanger 19 is cooled and condensed to obtain a high-temperature liquid high-pressure refrigerant (top 4), then with the help of the indoor controller 20, such as an electronic expansion valve, the high-pressure liquid is throttled and reduced its pressure in order to obtain a gas-liquid mixture (peak 5); at this moment, the refrigerant is divided into two streams, one of which is passed through the electronic expansion valve 21, throttled to obtain an intermediate pressure consisting of a gas-liquid mixture of refrigerant (top 8) and fed into the coil 18 filled with absorbent fluid reservoir 17, as a result which, after absorption of thermal energy, it turns into saturated intermediate pressure steam (top 9), then saturated intermediate pressure steam is absorbed by the second inlet 112 of compressor 11 for inlet gas; another refrigerant stream enters directly into the container formed between the shell of the liquid tank 17 and the coil 18 filled with absorbent material, exchanges heat with the refrigerant agent located in the coil 18 filled with absorbent material, releases heat energy, passes through the cooling coil 16 of the outdoor heat exchanger and condenses turning into a supercooled liquid (peak 6); the supercooled liquid is throttled using an outdoor regulator 15, such as an electronic expansion valve, to reach peak 7, after which it enters the outdoor heat exchanger 14 and turns into steam (peak 1) and is then sucked in by the gas inlet 111 of the compressor for gas inlet thereby closing the heating circuit.

The principle of operation of the entire air conditioning system using a heat pump is as follows. Under normal operating conditions, the present invention functions as a conventional air conditioning apparatus using a heat pump for cooling and heating; when the outdoor temperature drops significantly and the heat output decreases, a steam-jet system control device is activated, which injects saturated vapor of the intermediate pressure refrigerant into the compressor, due to which the compressor provides double compression and increases the heat and energy efficiency when the system is operating at low outdoor temperature. In addition, the compression ratio in the compressor and the temperature of the exhaust gases in the system are within reasonable limits; as the results of a large number of tests show, the system has high stability and reliability in operation; the system uses an intelligent defrost mode using a high pressure switch, which allows defrosting if necessary and stop defrosting when it is not required.

Second Embodiment

The second embodiment differs from the first embodiment in that, in the second embodiment, the sensors of the steam jet control device are temperature sensors, the principle of operation of the steam jet control device with temperature sensors is as follows: sensors located at the compressor openings for gas inlet and openings compressor for the release of gas, determine the temperature of the gas at the inlet and outlet of the compressor, then depending on changes in gas temperature at the input At the compressor outlet and exit, the degree of opening of the second gas inlet opening is controlled to control the volume of the steam jet. In this embodiment, the opening degree of the second gas inlet opening is controlled by changing the opening degree of the electronic expansion valve 21, wherein the following steps are carried out:

1) the temperature sensors determine the temperature of the gas, respectively, at the first compressor inlet for gas inlet, the second compressor inlet for gas inlet and the compressor outlet for gas, which is indicated, respectively, as T _lower , T _jet and T _urer ,

2) according to the relationship between pressure and temperature, the pressure P _lower and P _upper corresponding to T _lower and T _upper are calculated;

, и согласно зависимости между давлением и температурой вычисляют соответствующую температуру T_intermediate,3) calculate the intermediate pressure P _intermdiate when said compressor is running, while

, and according to the relationship between pressure and temperature, the corresponding temperature T _{intermediate is} calculated,

4) calculate the temperature difference ΔT _actual , which corresponds to the difference in actual pressures between the intermediate pressure of the compressor and the pressure of the jet from the second compressor inlet for gas inlet, while ΔT _actual = T _jet -T _intermediate ,

5) the difference N of the degrees of opening of the second gas inlet opening is calculated, wherein N = ΔT _target -ΔT _actual , where ΔT _target means the temperature difference of the corresponding predetermined target temperature difference,

6) determine the degree of actual opening of the second gas inlet opening, which is equal to the sum of the degree of its initial opening and the difference N of the degrees of opening.

Third Embodiment

As shown in FIG. 3, the third embodiment differs from the first embodiment in that in the third embodiment, the cooling coil 16 and the fluid reservoir 17 are absent in the heat pump system, and the coil 18 is also absent on the bypass pipe. In addition, said bypass pipe can be directly removed from the outlet of the heat exchanger located in the room.

The foregoing description and illustrations are not to be construed as limiting the scope of the present invention, which is described in the appended claims. Specialists in the art can suggest various improvements, alternative designs, and equivalents that are within the scope of the present invention, for example, replace the electronic expansion valve regulator with conventional capillary tubes, or use a single device in the room, or directly remove said bypass pipe from the outlet openings of the heat exchanger located in the room.

Claims (8)

1. An air conditioning system using a heat pump, having a four-way valve (13), an indoor heat exchanger (19), an indoor controller (20), an outdoor controller (15) and an outdoor heat exchanger (14), which connected in series to a circuit, characterized in that said air conditioning system using a heat pump further has a steam compressor system, which includes a compressor (11) having a first opening (111) for a gas inlet, a second gas inlet (112) and a gas outlet (113), wherein said first gas inlet (111) is connected to said four-way valve (13) by means of a gas and water separator (12), said second gas inlet opening (112) through a bypass pipe on which an electronic expansion valve (21) is arranged is connected to said indoor controller (20) and said outdoor controller (15), and said opening (113) for soy gas outlet dinene with said four-way valve (13); said indoor controller (20) by means of a fluid reservoir (17) is connected in series with said outdoor regulator (15), and said bypass pipe is located between said indoor controller (20) and said fluid reservoir (17); on the said bypass pipe is located a coil (18) located inside the said fluid reservoir (17). 2. An air conditioning system using a heat pump according to claim 1, characterized in that said steam compressor system further has a first sensor (201) located at the first gas inlet (111), a second sensor (202) located at the second gas inlet openings (112), and a third sensor (203) located at gas outlet (113). 3. An air conditioning system using a heat pump according to claim 2, characterized in that a set of cooling coils (16) is located between said liquid reservoir (17) and said outdoor heat exchanger (14). 4. An air conditioning system using a heat pump according to any one of claims 1 to 3, characterized in that the said sensors are pressure sensors. 5. An air conditioning system using a heat pump according to any one of claims 1 to 3, characterized in that the said sensors are temperature sensors. 6. A method for controlling an air conditioning system using a heat pump according to claim 1, including a method for controlling a steam compressor system, comprising the steps of:
stage 1: determine the state of the gas at the first gas inlet, the second gas inlet and the gas outlet, respectively designated as S _lower , S _jet and S _upper ,
stage 2: depending on the state of the gas S _lower at the first gas inlet and the state of gas S _upper at the gas outlet, calculate the state of gas S _intermediate when said compressor is operating,
stage 3: depending on the relationship between S _intermediate , S _jet and the predetermined target difference state S _{target, the} degree of opening of the second gas inlet opening is controlled. 7. The method of controlling an air conditioning system using a heat pump according to claim 6, characterized in that:
in step 1, the gas pressure is additionally determined at the first gas inlet opening, the second gas inlet opening and the compressor gas outlet openings, which are respectively designated as P _lower , P _jet and P _upper , and according to the relationship between pressure and temperature, the temperature T _{jet is} calculated corresponding to P _jet ,
in step 2, an intermediate pressure P _{intermediate is} additionally calculated when said compressor is operating, wherein

and according to the relationship between pressure and temperature, the corresponding temperature T _{intermediate is} calculated,
stage 3 further includes:
stage 30, in which the temperature difference Δ _{Tactual is calculated} , which corresponds to the difference in actual pressures between the intermediate pressure of the compressor and the pressure of the jet from the second compressor inlet for the gas inlet, with ΔT _actual = T _jet -T _intermediate ,
step 31, in which the difference N of the degrees of opening of the second gas inlet opening is calculated depending on the difference in actual temperatures ΔT _actual and the temperature difference ΔT _target corresponding to a predetermined target temperature difference, wherein N = ΔT _target -ΔT _actual ,
stage 32, in which it is determined that the degree of actual opening of the second gas inlet is equal to the sum of the degree of its initial opening and the difference N of the degrees of opening. 8. The method of controlling an air conditioning system using a heat pump according to claim 7, characterized in that:
in step 1, the gas temperature is additionally determined at the first gas inlet opening, the second gas inlet opening and the compressor gas outlet openings, which are respectively designated as T _lower , T _jet and T _upper , and the pressures P _lower are calculated according to the relationship between pressure and temperature and P _upper corresponding to T _lower and T _upper ,
in step 2, an intermediate pressure P _{intermediate is} additionally calculated when said compressor is operating, wherein

and according to the relationship between pressure and temperature, the corresponding temperature T _{intermediate is} calculated,
stage 3 further includes:
stage 30, which calculates the temperature difference ΔT _actual , which corresponds to the difference in actual pressures between the intermediate pressure of the compressor and the pressure of the jet from the second compressor inlet for gas inlet, while ΔT _actual = T _jet -T _intermediate ,
step 31, in which the difference N of the degrees of opening of the second gas inlet opening is calculated depending on the difference in actual temperatures ΔT _actual and the temperature difference ΔT _target corresponding to a predetermined target temperature difference, wherein N = ΔT _target -ΔT _actual ,
stage 32, in which it is determined that the degree of actual opening of the second gas inlet is equal to the sum of the degree of its initial opening and the difference N of the degrees of opening.

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