Air conditioner and air conditioning system with reduced refrigerant

Abstract

The present invention provides an air conditioner and an air conditioning system with reduced refrigerant. The air conditioner is added with a boosting device, and a bypass pipe is added on the basis of the first pipe and the second pipe. The internal expansion valve and the relay expansion valve can be controlled to increase the supercooling degree, thereby maximizing the supercooling degree of the refrigerant to enhance the heating and cooling capacity of the air conditioner. On this basis, the pipe diameter can be reduced, the amount of refrigerant accumulated in the liquid pipe can be reduced, and the heat transfer equivalent to the existing one can be achieved with a smaller refrigerant circulation volume, effectively reducing the impact of the greenhouse effect.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning refrigerants, and in particular to an air conditioner and an air conditioning system with reduced refrigerants. Background Art

[0002] Refrigerants used in air conditioners have the potential to cause global warming. Currently, fluorocarbons are the main refrigerants used. In order to reduce the greenhouse effect caused by refrigerants entering the atmosphere, the main countermeasure is to replace them with refrigerants with low global warming coefficients. However, methods to reduce the amount of refrigerants used have not been given enough attention or research.

[0003] However, in a multi-air conditioning system that uses a large amount of refrigerant, even if a refrigerant with a low global warming coefficient is used, the impact of the greenhouse effect cannot be effectively reduced due to its flammability. Summary of the invention

[0004] The present invention solves the problem that the existing air conditioning system uses a large amount of refrigerant, resulting in the greenhouse effect not being effectively reduced.

[0005] In order to solve the above problems, the present invention provides an air conditioner with reduced refrigerant, comprising an indoor unit, a relay unit and an outdoor unit;

[0006] The outdoor unit includes a compressor, a reversing component, a booster, an internal heat exchanger and an internal expansion valve, wherein the internal heat exchanger includes a first pipeline and a second pipeline; the relay unit includes a relay expansion valve, a relay heat exchanger and a relay solenoid valve; the relay heat exchanger includes a third pipeline and a fourth pipeline; a bypass pipe is also provided between the relay unit and the outdoor unit; the indoor unit includes an indoor expansion valve and an indoor heat exchanger;

[0007] The outlet of the boosting device is connected to the air intake port of the compressor, and the inlet is connected to the reversing component; one end of the bypass pipe is connected to the inlet of the boosting device, and the other end is connected to the indoor heat exchanger through the relay solenoid valve;

[0008] One end of the first pipeline is connected to the reversing component, and the other end is connected to the relay heat exchanger; one end of the second pipeline is connected to the reversing component through the internal expansion valve, and the other end is connected between the relay solenoid valve and the booster; one end of the third pipeline is connected to the other end of the first pipeline through a first pipe, and the other end of the third pipeline is connected to the indoor expansion valve; one end of the fourth pipeline is connected to the indoor expansion valve through the relay expansion valve, and the other end is connected between the relay solenoid valve and the booster;

[0009] The indoor heat exchanger is connected to the reversing component via a second pipe;

[0010] In cooling mode, the relay solenoid valve is set to open, the relay expansion valve is set to fully closed, and the internal expansion valve is used to control and increase the degree of supercooling; in heating mode, the internal expansion valve is set to fully closed, the relay solenoid valve is set to closed, and the relay expansion valve is used to control and increase the degree of supercooling.

[0011] The air conditioner of the embodiment of the present invention has a booster device added, and a bypass pipe added on the basis of the first pipe and the second pipe, which can control the internal expansion valve and the relay expansion valve to increase the supercooling degree, thereby maximizing the supercooling degree of the refrigerant to enhance the heating and cooling capacity of the air conditioner. On this basis, the pipe can be made thinner, the amount of refrigerant accumulated in the liquid pipe can be reduced, and the heat transport equivalent to the existing one can be achieved with a smaller amount of refrigerant circulation, effectively reducing the impact of the greenhouse effect. By applying the present invention, the amount of refrigerant in the existing liquid pipe can be reduced by about 40%.

[0012] Optionally, the relay unit further includes a throttling component; the throttling component is connected between the relay solenoid valve and the indoor heat exchanger.

[0013] In the embodiment of the present invention, by controlling the opening and closing of the relay solenoid valve, it is possible to control whether the refrigerant flowing out of the indoor heat exchanger passes through the throttling component and then enters the boosting device through the bypass pipe, thereby further improving the cooling capacity.

[0014] Optionally, the outdoor unit also includes an outdoor heat exchanger and an outdoor expansion valve; the outdoor heat exchanger and the outdoor expansion valve are connected between the reversing component and the internal heat exchanger; one end of the first pipeline is connected to the reversing component through the outdoor heat exchanger and the outdoor expansion valve; one end of the second pipeline is connected to the reversing component through the internal expansion valve, the outdoor heat exchanger and the outdoor expansion valve.

[0015] The embodiment of the present invention can further improve the heat exchange capacity of the outdoor unit through the outdoor heat exchanger and the outdoor expansion valve.

[0016] Optionally, the outdoor unit further includes a gas-liquid separator; the gas-liquid separator is connected between the boosting device and the compressor.

[0017] In the embodiment of the present invention, the refrigerant first enters the gas-liquid separator and then enters the compressor, so that the liquid refrigerant can be separated from the gas refrigerant to prevent the liquid refrigerant from causing liquid shock to damage the compressor.

[0018] Optionally, the reversing component is a four-way valve; in cooling mode, the four-way valve connects the compressor and the outdoor heat exchanger, and connects the indoor heat exchanger and the boosting device; in heating mode, the four-way valve connects the boosting device and the outdoor heat exchanger, and connects the indoor heat exchanger and the compressor.

[0019] In the embodiment of the present invention, the reversing component adopts a four-way valve, which can realize the flow direction control of the refrigerant for cooling and heating.

[0020] Optionally, the boosting device is an ejector, a compressor or a refrigerant pump.

[0021] Optionally, the throttling component is a capillary tube or an expansion valve.

[0022] The embodiments of the present invention provide specific devices used in the boosting device and the throttling component, which can maximize the supercooling degree of the refrigerant to enhance the heating and cooling capacity of the air conditioner. On this basis, the diameter of the pipe can be reduced to reduce the amount of refrigerant accumulated in the liquid pipe.

[0023] Optionally, the first pipe, the second pipe, and the bypass pipe are all small-diameter pipes.

[0024] Optionally, the diameter of the thin-diameter pipe is less than or equal to 9.52 mm.

[0025] In the embodiment of the present invention, each pipe is configured as a thin-diameter pipe and a specific pipe diameter range is provided, so that the amount of refrigerant accumulated in the pipe connecting the outdoor unit and the indoor unit can be reduced.

[0026] The present invention provides an air-conditioning system, comprising the above-mentioned refrigerant-reducing air conditioner; the number of the indoor units is multiple; the indoor expansion valve of each of the indoor units is connected to the relay heat exchanger and the relay expansion valve, and the indoor heat exchanger of each of the indoor units is connected to the reversing component and the throttling component.

[0027] The air conditioning system provided by the present invention can achieve the same technical effect as the above-mentioned air conditioner with reduced refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a refrigeration cycle of an air conditioner with reduced refrigerant provided by an embodiment of the present invention;

[0029] Figure 2 This is the ph line diagram of the original refrigeration operation;

[0030] Figure 3 is a pH diagram of refrigeration operation in one embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a heating cycle of an air conditioner with reduced refrigerant provided by an embodiment of the present invention;

[0032] Figure 5 This is the ph line diagram of the original heating operation;

[0033] Figure 6FIG. 4 is a pH diagram of heating operation in one embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0035] The embodiment of the present invention provides an air conditioner with reduced refrigerant, which can maximize the supercooling degree of high-pressure liquid refrigerant, carry out heat transfer equivalent to the existing one with less refrigerant circulation, reduce the pressure loss of liquid piping, and realize the thinning of liquid piping. Due to the thinning of the liquid piping, the amount of liquid refrigerant accumulated in the liquid piping is reduced, and the amount of refrigerant in the existing liquid piping can be reduced by about 40%.

[0036] An embodiment of the present invention provides an air conditioner with reduced refrigerant, including an indoor unit, a relay unit and an outdoor unit.

[0037] The outdoor unit includes a compressor, a reversing component, a booster, an internal heat exchanger and an internal expansion valve, and the internal heat exchanger includes a first pipeline and a second pipeline. The relay unit includes a relay expansion valve, a relay heat exchanger and a relay solenoid valve, and the relay heat exchanger includes a third pipeline and a fourth pipeline; a bypass pipe is also provided between the relay unit and the outdoor unit. The indoor unit includes an indoor expansion valve and an indoor heat exchanger.

[0038] The indoor unit and the outdoor unit are connected through the first pipe and the second pipe, and the relay unit is arranged on the first pipe and the second pipe. In addition, the relay unit is also provided with a bypass pipe, and the bypass pipe connects the relay unit and the outdoor unit. For example, the first pipe and the second pipe are a liquid pipe and a gas pipe respectively.

[0039] Specifically, the outlet of the booster is connected to the air intake of the compressor, and the inlet is connected to the reversing component; one end of the bypass pipe is connected to the inlet of the booster, and the other end is connected to the indoor heat exchanger through a relay solenoid valve. The booster is used to increase the pressure of the refrigerant and then return it to the compressor. Due to the presence of the booster to increase the pressure of the refrigerant, the pressure can be reduced to a pressure lower than the suction pressure of the compressor during heat exchange in the heat exchanger, thereby further increasing the degree of supercooling. Optionally, the degree of supercooling can be increased by controlling the internal expansion valve, the relay expansion valve, and the indoor expansion valve.

[0040] Since simply reducing the diameter of the pipe will increase the pressure loss of the pipe, which will greatly reduce the cooling and heating capacity of the air conditioner, the above structure of this embodiment can increase the supercooling degree to improve the cooling and heating capacity of the air conditioner. On this basis, reducing the diameter of the pipe can meet the cooling and heating needs and reduce the circulation amount of the refrigerant. Therefore, on the basis of increasing the supercooling degree, the diameter of the pipe can be reduced without causing the loss of the cooling and heating capacity of the air conditioner.

[0041] Specifically, one end of the first pipeline is connected to the reversing component, and the other end is connected to the relay heat exchanger; one end of the second pipeline is connected to the reversing component through the internal expansion valve, and the other end is connected between the relay solenoid valve and the booster. One end of the third pipeline is connected to the other end of the first pipeline through the first piping, and the other end of the third pipeline is connected to the indoor expansion valve; one end of the fourth pipeline is connected to the indoor expansion valve through the relay expansion valve, and the other end is connected between the relay solenoid valve and the booster.

[0042] Based on the above structure, the boosting device is connected to a pipeline of the internal heat exchanger of the outdoor unit, the bypass pipe (directly connected to the indoor unit, or connected to the indoor unit through a relay heat exchanger and a relay expansion valve), and the reversing component, so as to boost the refrigerant transported by the above structure to a pressure higher than the minimum suction pressure of the compressor, and then send it into the compressor.

[0043] Specifically, the indoor heat exchanger is connected to the reversing member through the second pipe.

[0044] In cooling mode, the relay solenoid valve is set to open, the relay expansion valve is set to fully closed, and the internal expansion valve is used to control the degree of supercooling. The internal expansion valve is controlled so that the degree of supercooling of the refrigerant flowing out of the outlet of the internal heat exchanger is maximized, and the refrigerant enters the bypass pipe through the connecting pipe between the internal heat exchanger and the bypass pipe, and then enters the booster device.

[0045] In heating mode, the internal expansion valve is set to fully closed, the relay solenoid valve is set to closed, and the relay expansion valve is used to control and increase the degree of supercooling. The relay expansion valve of the relay unit is controlled to maximize the supercooling of the refrigerant flowing out of the relay heat exchanger outlet, and the refrigerant enters the booster through the bypass pipe.

[0046] Exemplarily, the boosting device may be an ejector, a compressor or a refrigerant pump, all of which can boost the refrigerant pressure.

[0047] Under the premise that the air conditioner improves the supercooling degree of the refrigerant through the above structure, the first pipe, the second pipe, and the bypass pipe can all adopt small diameter pipes. For example, the diameter of the small diameter pipe is less than or equal to 9.52 mm. By adopting small diameter pipes, the amount of refrigerant in the pipes can be effectively reduced.

[0048] The refrigerant-reduced air conditioner provided by the embodiment of the present invention has a booster device added, and a bypass pipe added on the basis of the first pipe and the second pipe, and the internal expansion valve and the relay expansion valve can be controlled to increase the supercooling degree, thereby maximizing the supercooling degree of the refrigerant to enhance the heating and cooling capacity of the air conditioner. On this basis, the pipe can be made thinner, the amount of refrigerant accumulated in the liquid pipe can be reduced, and the heat transport equivalent to the existing one can be achieved with a smaller amount of refrigerant circulation, effectively reducing the impact of the greenhouse effect. By applying the present invention, the amount of refrigerant in the existing liquid pipe can be reduced by about 40%.

[0049] Furthermore, in order to further increase the cooling capacity, a throttling component is also provided in the relay unit; the throttling component is connected between the relay solenoid valve and the indoor heat exchanger. By controlling the opening and closing of the relay solenoid valve, it is possible to control whether the refrigerant flowing out of the indoor heat exchanger passes through the throttling component and then enters the boosting device through the bypass pipe. For example, the throttling component can be a capillary tube or an expansion valve.

[0050] In cooling mode, the relay control valve is open, and the refrigerant flowing out of the indoor heat exchanger passes through the throttling component, and then enters the booster through the bypass pipe; in heating mode, the relay control valve is closed, and the refrigerant flowing out of the indoor heat exchanger passes through the relay expansion valve and the relay heat exchanger, and then enters the booster through the bypass pipe, and no longer passes through the throttling component. Based on the throttling effect of the throttling component, the supercooling degree of the refrigerant can be further improved.

[0051] Optionally, the outdoor unit further includes an outdoor heat exchanger and an outdoor expansion valve; the outdoor heat exchanger and the outdoor expansion valve are connected between the reversing component and the internal heat exchanger; one end of the first pipeline is connected to the reversing component through the outdoor heat exchanger and the outdoor expansion valve; one end of the second pipeline is connected to the reversing component through the internal expansion valve, the outdoor heat exchanger and the outdoor expansion valve. The outdoor heat exchanger and the outdoor expansion valve can further improve the heat exchange capacity of the outdoor unit.

[0052] Optionally, the outdoor unit further includes a gas-liquid separator; the gas-liquid separator is connected between the boost device and the compressor. The refrigerant first enters the gas-liquid separator and then enters the compressor, which can separate the liquid refrigerant from the gas refrigerant to prevent the liquid refrigerant from causing liquid shock to damage the compressor.

[0053] Optionally, the reversing component is a four-way valve; in cooling mode, the four-way valve connects the compressor and the outdoor heat exchanger, and connects the indoor heat exchanger and the boosting device; in heating mode, the four-way valve connects the boosting device and the outdoor heat exchanger, and connects the indoor heat exchanger and the compressor.

[0054] The embodiment of the present invention can reduce the amount of refrigerant accumulated in the piping connecting the outdoor unit and the indoor unit. The existing technology of reducing the amount of refrigerant by treating the refrigerant flowing in the liquid piping as a gas-liquid mixed refrigerant has a reduced refrigeration effect, a reduced capacity problem, and a piping pressure loss of more than 6 times. Therefore, in a multi-split air conditioner assembled with a long piping of more than 90m, the refrigerant sometimes has fatal problems such as no flow. Therefore, in the embodiment of the present invention, the amount of liquid refrigerant is reduced by reducing the diameter of the piping.

[0055] Since the refrigerant in the liquid pipe is in liquid phase, its density is about 50 times higher than that in the gas pipe. The pipe diameter is reduced to The amount of refrigerant is reduced by 49.1% with the following calculation formula.

[0056] Refrigerant volume of pipe Mb = (3.14*(12.7-2*0.8) 2 / 4)*L*ρ

[0057] Refrigerant volume of pipe Ma = (3.14*(9.52-2*0.8) 2 / 4)*L*ρ

[0058] (Refrigerant amount reduction ratio) = 1-Ma / Mb = 0.4909≒0.491

[0059] Among them, the pipe thickness is 0.8 [mm], the pipe length is L [m], and the refrigerant density is ρ [kg / m3].

[0060] If the diameter is simply reduced, the pressure loss of the pipe will increase by about 5 times, resulting in the same problem as the above-mentioned gas-liquid mixed transportation. Therefore, in the embodiment of the present invention, a countermeasure for increasing the degree of supercooling of the liquid refrigerant is also provided. The capacity Q of the refrigerant side is shown in the following formula. Under the condition of maintaining the same capacity, the circulation volume G and the enthalpy difference Δh are inversely proportional.

[0061] Q=G·Δh

[0062] Figure 1 A schematic diagram of a refrigeration cycle of an air conditioner with reduced refrigerant provided by an embodiment of the present invention. For example, in the refrigeration cycle, in addition to the usual refrigeration cycle, the outdoor unit is also equipped with an ejector, a relay unit is provided between the outdoor unit and the indoor unit, the relay unit has a built-in relay expansion valve, a relay heat exchanger and a relay solenoid valve, and the outdoor unit and the relay unit are connected by three pipes (gas pipe, liquid pipe, bypass pipe).

[0063] like Figure 1As shown, the outdoor unit 100 includes a compressor 101, a gas-liquid separator 102, an ejector 103, a four-way valve 104, an internal heat exchanger 105, an internal expansion valve 106, an outdoor heat exchanger 107, and an outdoor expansion valve 108; the relay unit 200 includes a relay expansion valve 201, a relay heat exchanger 202 and a relay solenoid valve 203; the indoor unit 300 includes multiple indoor expansion valves 301 and multiple indoor heat exchangers 302.

[0064] The compressor 101 performs feedback control to keep the low pressure constant. The low pressure decreases when the speed of the compressor is increased, and increases when the speed is reduced, so the speed of the compressor is controlled while the low pressure is detected. The internal expansion valve 106 is controlled to maximize the subcooling degree of the refrigerant at the outlet temperature of the internal heat exchanger 105, the relay solenoid valve 203 of the relay unit is open, and the relay expansion valve 201 is fully closed. Specifically, the subcooling degree at a certain time t is Sc(t), and the expansion valve opening is PI(t). The expansion valve opening at the next time t+1 is calculated as follows:

[0065] PI(t+1)=PI(t)+α×[{Sc(t)-Sc(t-1)} / {PI(t)-PI(t-1)}]

[0066] Here, α is the control convergence rate, and the appropriate value can be determined through experiments.

[0067] The refrigerant flow during refrigeration operation is as follows Figure 1 As shown by the middle arrow. In the outdoor unit, the refrigerant is divided into two paths after passing through the outdoor expansion valve 108, and enters the internal heat exchanger 105 and the internal expansion valve 106 respectively. The refrigerant entering the internal expansion valve 106 enters the bypass pipe 600 after passing through the internal heat exchanger 105, and then enters the ejector 103 for pressure increase; the refrigerant entering the internal heat exchanger 105 enters the relay heat exchanger 202 through the liquid pipe 400, at which time the relay expansion valve 201 is fully closed and does not pass through the relay expansion valve 201. In the indoor unit, the refrigerant is divided into two paths after flowing out of the indoor heat exchanger 302, one path flows through the gas pipe 500 through the four-way valve 104 and enters the ejector 103, and the other path enters the ejector 103 through the bypass pipe 600. The bypass pipe 600 is provided with a capillary tube 601 and a relay solenoid valve 203.

[0068] The internal expansion valve is opened, and the connection between the internal heat exchanger and the bypass pipe 600 is connected; the relay expansion valve is fully closed, and the connection between the relay heat exchanger and the bypass pipe 600 is disconnected.

[0069] In the embodiment of the present invention, the refrigerant that has been decompressed by internal heat exchange is pressurized by the ejector and returned to the compressor, thereby allowing the refrigerant to be decompressed to a pressure lower than the suction pressure of the compressor during heat exchange, further increasing the degree of supercooling.

[0070] The following is a description of specific embodiments in cooling and heating operation. The parameters of the air conditioner are as follows: air conditioning capacity: 12HP, pipe length: 90 [m], refrigerant R410A, original pipe diameter: liquid pipe diameter Air pipe diameter Pipe diameter of the embodiment of the present invention: Liquid pipe diameter Air pipe diameter Bypass pipe diameter

[0071] (1) Existing air conditioner

[0072] Assuming the subcooling degree is 5°C, the pressure loss during rated refrigeration operation is given by the following formula. Figure 2 The ph line diagram of the original refrigeration operation is shown.

[0073] (Liquid pipe pressure loss) = (λ·(L / d)·ρv 2 ) / 2

[0074] =1.37*10 -2 ×(90 / (12.7-2*0.8))×950·2.39 2 / 2×10 -6

[0075] =0.30[MPa]

[0076] Wherein, λ: pipe friction coefficient, L: piping length, d: pipe inner diameter, ρ: refrigerant density (=950 [kg / m3]), v: refrigerant velocity (v=G / (ρ·S)), S: cross-sectional area inside the pipe [m2], G: refrigerant circulation volume equivalent to 12HP cooling capacity (=0.22 [kg / sec]).

[0077] At this time, the amount of refrigerant in the liquid pipe is as follows:

[0078] (Amount of refrigerant in liquid pipe)=950*90*(3.14*(12.7-2*0.8) 2 / 4) / (10 6 )=8.27[kg]

[0079] (2) Air conditioner in the embodiment of the present invention

[0080] Figure 3 FIG. 2 shows a ph line diagram of the cooling operation in an embodiment of the present invention. Figure 3 As shown in the figure, the 0 part in the figure is the change in enthalpy difference caused by internal heat exchange. In this cycle, since the internal heat exchanger can achieve a large degree of supercooling, the refrigeration effect is shown in the following formula, which is 1.58 times that of the past, and the circulation volume can be reduced by 0.63 times.

[0081] (Refrigeration effect ratio) = (Refrigeration effect of the present invention) / (Original Refrigeration effect)

[0082] =(430-187) / (430-276)=1.58

[0083] (Liquid pipe pressure loss) = (λ·(L / d)·ρv 2 ) / 2

[0084] =1.37*10 -2 ×(90 / (9.52-2*0.8))×950·2.99 2 / 2×10 -6

[0085] =0.66[MPa]

[0086] Wherein, λ: pipe friction coefficient, L: piping length, d: pipe inner diameter, ρ: refrigerant density (=950[kg / m3]), v: refrigerant velocity (v=G / (ρ·S)), S: cross-sectional area inside the pipe, G: refrigerant circulation volume equivalent to 12HP cooling capacity (=0.22*0.63≒0.14[kg / sec]).

[0087] Although the piping pressure loss increases, the high and low differential pressure is 2.0 [MPa], which is well within the control range of the expansion valve, providing a cooling capacity that meets the requirements. At this time, the amount of refrigerant in the liquid pipe is as follows.

[0088] (Amount of refrigerant in liquid pipe)=950*90*(3.14*(9.52-2*0.8) 2 / 4) / (10 6 )=4.21[kg]

[0089] In addition, since the outdoor unit and indoor unit are connected in a three-pipe type, refrigerant is also accumulated in the bypass pipe. Taking the amount of refrigerant in the bypass pipe into account, the refrigerant is reduced by 38% as shown in the following formula.

[0090] (Bypass pipe refrigerant volume) = 46*90*(3.14*(19.05-2*1) 2 / 4) / (10 6 )=0.94[kg]

[0091] (Refrigerant volume reduction ratio) = 1 – (4.21 + 0.94) / 8.27 = 0.38

[0092] Figure 4 A schematic diagram of a heating cycle of an air conditioner with reduced refrigerant according to an embodiment of the present invention. The refrigerant flow during heating operation is as follows: Figure 4 Indicated by the arrow.

[0093] The compressor 101 performs feedback control to keep the high pressure constant. If the compressor speed is increased, the high pressure will rise, and if the speed is reduced, it will fall. Therefore, the compressor speed is controlled while the high pressure is detected, and the internal expansion valve 106 is set to be fully closed. The relay expansion valve 201 of the relay unit is controlled to maximize the refrigerant subcooling at the outlet temperature of the relay heat exchanger 202. Specifically, the subcooling degree at a certain time t is Sc(t), and the expansion valve opening is PI(t). The expansion valve opening at the next time t+1 is calculated as follows:

[0094] PI(t+1)=PI(t)+α×[{Sc(t)-Sc(t-1)} / {PI(t)-PI(t-1)}]

[0095] In the relay unit, the refrigerant is divided into two paths after passing through the indoor expansion valve 301, and enters the relay heat exchanger 202 and the relay expansion valve 201 respectively. The refrigerant entering the relay expansion valve 201 enters the bypass pipe 600 after passing through the relay heat exchanger 202, and then enters the ejector 103 for pressure increase; the refrigerant entering the relay heat exchanger 202 enters the internal heat exchanger 105 through the liquid pipe 400, at which time the internal expansion valve 106 is fully closed and does not pass through the internal expansion valve 106. The relay solenoid valve 203 is closed, and the refrigerant in the gas pipe 500 does not enter the bypass pipe 600, but enters the indoor heat exchanger 302.

[0096] The internal expansion valve is fully closed, and the connection between the internal heat exchanger and the bypass pipe 600 is disconnected; the relay expansion valve is opened, and the connection between the relay heat exchanger and the bypass pipe 600 is connected.

[0097] In the embodiment of the present invention, the refrigerant that has been decompressed by internal heat exchange is pressurized by the ejector and returned to the compressor, thereby allowing the refrigerant to be decompressed to a pressure lower than the suction pressure of the compressor during heat exchange, further increasing the degree of supercooling.

[0098] (1) Existing air conditioner

[0099] Assuming the subcooling degree is 5°C, the pressure loss in rated heating operation is given by the following formula. Figure 5 The ph line diagram of the original heating operation is shown.

[0100] (Liquid pipe pressure loss) = (λ·(L / d)·ρv 2 ) / 2

[0101] =1.37*10 -2 ×(90 / (12.7-2*0.8))×950·1.96 2 / 2×10 -6

[0102] =0.20[MPa]

[0103] Wherein, λ: pipe friction coefficient, L: pipe length, d: pipe inner diameter, ρ: refrigerant density (=950 [kg / m3]), v: refrigerant velocity (v=G / (ρ·S)), S: cross-sectional area inside the pipe, G: refrigerant circulation volume equivalent to 12HP heating capacity (0.18 [kg / sec]).

[0104] At this time, the amount of refrigerant in the liquid pipe is shown in the following formula.

[0105] (Amount of refrigerant in liquid pipe)=950*90*(3.14*(12.7-2*0.8) 2 / 4) / (10 6 )=8.27[kg]

[0106] The key is to ensure supercooling of the refrigerant coming out of the indoor unit with the relay unit and reduce the circulation volume of the liquid pipe. In addition, in the piping between the indoor unit and the relay unit, it is best to install the relay unit as close to the indoor unit as possible.

[0107] (2) Air conditioner in the embodiment of the present invention

[0108] Figure 6 FIG. 2 shows a ph line diagram of heating operation in an embodiment of the present invention. Figure 6 As shown in the figure, the 0 part in the figure is the change in enthalpy difference caused by internal heat exchange. In this cycle, the relay heat exchanger can achieve a large degree of supercooling, and its heating effect is shown in the following formula, which is 1.60 times that of the past, and the circulation volume can be reduced by 0.63 times.

[0109] (Heating effect ratio) = (Heating effect of the present invention) / (Existing heating effect)

[0110] =(426-178) / (426-271)=1.60

[0111] (Liquid pipe pressure loss) = (λ·(L / d)·ρv 2 ) / 2

[0112] =1.37*10 -2 ×(90 / (9.52-2*0.8))×950·2.40 2 / 2×10 -6

[0113] =0.43[MPa]

[0114] Among them, λ: pipe friction coefficient, L: piping length, d: pipe inner diameter, ρ: refrigerant density (=950[kg / m3]), v: refrigerant velocity (v=G / (ρ·S)), S: cross-sectional area inside the pipe, G: refrigerant circulation volume equivalent to 12HP heating capacity (=0.18*0.63≒0.11[kg / sec]).

[0115] Although the piping pressure loss increases, the high and low differential pressure is 2.2 [MPa], which is well within the control range of the expansion valve, providing heating capacity that meets the requirements. At this time, the amount of refrigerant in the liquid pipe is as follows.

[0116] (Amount of refrigerant in liquid pipe)=950*90*(3.14*(9.52-2*0.8) 2 / 4) / (10 6 )=4.21[kg]

[0117] In addition, since the outdoor unit and indoor unit are connected in a three-pipe type, refrigerant is also accumulated in the bypass pipe. Taking the amount of refrigerant in the bypass pipe into account, the refrigerant is reduced by 40% as shown in the following formula.

[0118] (Bypass pipe refrigerant volume) = 37*90*(3.14*(19.05-2*1) 2 / 4) / (10 6 )=0.76[kg]

[0119] (Refrigerant volume reduction ratio) = 1 – (4.21 + 0.76) / 8.27 = 0.40

[0120] An embodiment of the present invention provides an air-conditioning system, comprising the above-mentioned refrigerant-reducing air conditioner; the number of the indoor units is multiple; the indoor expansion valve of each of the indoor units is connected to the relay heat exchanger and the relay expansion valve, and the indoor heat exchanger of each of the indoor units is connected to the reversing component and the throttling component.

[0121] Of course, those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the control device through a computer, and the program can be stored in a computer-readable storage medium. When the program is executed, it may include the processes of the above-mentioned method embodiments, wherein the storage medium may be a memory, a disk, an optical disk, etc.

[0122] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

[0123] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0124] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. An air conditioner with reduced refrigerant, characterized in that: Including indoor unit, relay unit and outdoor unit; The outdoor unit includes a compressor, a reversing component, a booster, an internal heat exchanger and an internal expansion valve, wherein the internal heat exchanger includes a first pipeline and a second pipeline; the relay unit includes a relay expansion valve, a relay heat exchanger and a relay solenoid valve; the relay heat exchanger includes a third pipeline and a fourth pipeline; a bypass pipe is also provided between the relay unit and the outdoor unit; the indoor unit includes an indoor expansion valve and an indoor heat exchanger; The outlet of the boosting device is connected to the air intake port of the compressor, and the inlet is connected to the reversing component; one end of the bypass pipe is connected to the inlet of the boosting device, and the other end is connected to the indoor heat exchanger through the relay solenoid valve; One end of the first pipeline is connected to the reversing component, and the other end is connected to the relay heat exchanger; one end of the second pipeline is connected to the reversing component through the internal expansion valve, and the other end is connected between the relay solenoid valve and the booster; one end of the third pipeline is connected to the other end of the first pipeline through a first pipe, and the other end of the third pipeline is connected to the indoor expansion valve; one end of the fourth pipeline is connected to the indoor expansion valve through the relay expansion valve, and the other end is connected between the relay solenoid valve and the booster; The indoor heat exchanger is connected to the reversing component via a second pipe; In cooling mode, the relay solenoid valve is set to open, the relay expansion valve is set to fully closed, and the internal expansion valve is used to control and increase the degree of supercooling; in heating mode, the internal expansion valve is set to fully closed, the relay solenoid valve is set to closed, and the relay expansion valve is used to control and increase the degree of supercooling; The indoor unit is connected to the outdoor unit via the first pipe and the second pipe, and the first pipe, the second pipe, and the bypass pipe are all small-diameter pipes; The diameter of the narrow-diameter pipe is less than or equal to 9.52 mm.

2. The refrigerant-reducing air conditioner according to claim 1, characterized in that: The relay unit also includes a throttling component; The throttling component is connected between the relay solenoid valve and the indoor heat exchanger.

3. The refrigerant-reducing air conditioner according to claim 1, characterized in that: The outdoor unit also includes an outdoor heat exchanger and an outdoor expansion valve; The outdoor heat exchanger and the outdoor expansion valve are connected between the reversing component and the internal heat exchanger; One end of the first pipeline is connected to the reversing component through the outdoor heat exchanger and the outdoor expansion valve; One end of the second pipeline is connected to the reversing component through the internal expansion valve, the outdoor heat exchanger and the outdoor expansion valve.

4. The refrigerant-reducing air conditioner according to claim 1, characterized in that: The outdoor unit also includes a gas-liquid separator; The gas-liquid separator is connected between the boosting device and the compressor.

5. The refrigerant-reducing air conditioner according to claim 3, characterized in that: The reversing component is a four-way valve; In cooling mode, the four-way valve conducts the compressor and the outdoor heat exchanger, and conducts the indoor heat exchanger and the boosting device; In the heating mode, the four-way valve conducts the boosting device and the outdoor heat exchanger, and conducts the indoor heat exchanger and the compressor.

6. The refrigerant-reducing air conditioner according to any one of claims 1 to 5, characterized in that: The pressure boosting device is an ejector, a compressor or a refrigerant pump.

7. The refrigerant-reducing air conditioner according to any one of claims 2 to 5, characterized in that: The throttling component is a capillary tube or an expansion valve.

8. An air conditioning system, characterized in that: An air conditioner with reduced refrigerant comprising any one of claims 1 to 7; There are multiple indoor units; the indoor expansion valve of each indoor unit is connected to the relay heat exchanger and the relay expansion valve, and the indoor heat exchanger of each indoor unit is connected to the reversing component and the throttling component.

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