Constant-frequency air conditioner refrigerating capacity adjusting method and constant-frequency air conditioner

Abstract

According to the method for adjusting the refrigerating capacity of the fixed-frequency air conditioner, the fixed-frequency air conditioner comprises a refrigerating main loop and a hot gas bypass loop, a bypass valve is arranged on the hot gas bypass loop, and a throttling device and a draught fan are arranged on the refrigerating main loop. The fixed-frequency air conditioner adjusts the on-off state of the bypass valve, the opening degree of the throttling device and / or the air volume of the fan according to the set range condition so as to adjust the refrigerating capacity. The invention further provides a fixed-frequency air conditioner which is provided with the refrigerating capacity adjusting method. According to the method for adjusting the refrigerating capacity of the fixed-frequency air conditioner and the fixed-frequency air conditioner, by arranging the hot air bypass loop, the opening degree of the throttling device and the air volume of the draught fan are adjusted, and therefore the refrigerating capacity of the refrigerating loop is adjusted.

Description

Technical Field

[0001] The invention relates to the technical field of heating and ventilation, and in particular to a method for adjusting the cooling capacity of a fixed-frequency air conditioner and a fixed-frequency air conditioner. Background Art

[0002] When fixed-frequency air-conditioning units are used in rail vehicle air conditioning, the cooling capacity adjustment range is limited. When the vehicle environment is changeable, the temperature changes vary greatly, and the cooling capacity demand range is wide, its conventional 5-level adjustment method cannot meet the use requirements, and there are problems such as frequent start and stop, limited temperature control accuracy and high power consumption. Summary of the invention

[0003] The main purpose of the present invention is to solve the above-mentioned problems and shortcomings, and to provide a method for adjusting the cooling capacity of a fixed-frequency air conditioner and a fixed-frequency air conditioner, by setting a hot gas bypass circuit, adjusting the opening of the throttling device and the air volume of the fan, thereby realizing the adjustment of the cooling capacity of the refrigeration circuit.

[0004] To achieve the purpose of the invention, the present invention first provides a method for adjusting the cooling capacity of a fixed-frequency air conditioner, which adopts the following technical solution:

[0005] A method for regulating the cooling capacity of a fixed-frequency air conditioner, the fixed-frequency air conditioner comprising a main refrigeration circuit and a hot gas bypass circuit, the hot gas bypass circuit being provided with a bypass valve, the main refrigeration circuit being provided with a throttling device and a fan, the fixed-frequency air conditioner adjusting the on-off of the bypass valve and the opening of the throttling device and / or the air volume of the fan according to set range conditions to regulate the cooling capacity.

[0006] Furthermore, when predetermined conditions are met, the throttling device and the fan remain unchanged within a range.

[0007] Furthermore, the setting condition includes latitude information of the fixed-frequency air conditioner.

[0008] Furthermore, the set conditions include ambient humidity.

[0009] Furthermore, the main refrigeration circuit includes a compressor, a condenser, a throttling device and an evaporator connected in sequence, and one end of the hot gas bypass circuit is connected to the outlet of the compressor, and the other end is connected to the outlet of the electronic expansion valve.

[0010] Furthermore, the main refrigeration circuit includes a compressor, a condenser, a throttling device and an evaporator. One end of the hot gas bypass circuit is connected to the pipeline between the compressor outlet and the condenser inlet, and the other end is connected to the pipeline between the evaporator inlet and the throttling device outlet.

[0011] Furthermore, the operating conditions include:

[0012] When K>x, the fixed-frequency air conditioner operates at the maximum gear state, wherein the condensing fan speed is m1, the evaporating fan speed is m2, and the throttling device opening is m3;

[0013] When y≤K<x, the fixed-frequency air conditioner operates in a mid-range state, wherein the condensing fan speed is n1, the evaporating fan speed is n2, and the throttling device opening is n3;

[0014] When z≤K<y, the fixed-frequency air conditioner operates in a low-speed state, wherein the condensing fan speed is p1, the evaporating fan speed is p2, and the throttling device opening is p3;

[0015] Where K is the judgment condition value, K = a*K1+b*K2,

[0016] K1 is the first judgment constant, which is related to latitude and ambient temperature, and its value range is 10 to 60;

[0017] K2 is the second judgment constant, which is related to the ambient humidity and vehicle type, and its value range is 30 to 90;

[0018] a is a coefficient, and its value range is 0.6 to 0.9, which is set according to usage requirements;

[0019] b is a coefficient, and its value range is 0.2 to 0.5, which is set according to usage requirements;

[0020] x, y, and z are set values. x is in the range of 32 to 40, y is in the range of 22 to 30, and z is in the range of 10 to 19.

[0021] Furthermore, the higher the latitude and the lower the ambient temperature, the smaller the value of K1.

[0022] Furthermore, the lower the temperature and the smaller the compartment, the smaller the value of K2.

[0023] The second invention object of the present invention is to provide a fixed-frequency air conditioner, which adopts the following technical solution:

[0024] A fixed-frequency air conditioner comprises a controller, a main refrigeration circuit and a hot gas bypass circuit, wherein the hot gas bypass circuit is provided with a bypass valve, and the main refrigeration circuit is provided with a throttling device and a fan, and a fixed-frequency air conditioner refrigeration capacity adjustment method as described above is preset in the controller.

[0025] In summary, the method for adjusting the cooling capacity of a fixed-frequency air conditioner and the fixed-frequency air conditioner provided by the present invention have the following technical advantages compared with the prior art:

[0026] The invention solves the problem that the fixed-frequency air conditioner in the prior art can only adjust the cooling capacity according to the set temperature and the ambient temperature or adjust the cooling capacity in stages, and realizes real-time adjustment of the cooling capacity according to the operating environment;

[0027] The latitude information is added to the operating environment conditions to solve the impact of different latitudes and environmental pressures on cooling capacity;

[0028] The structure is simple and can realize stepless regulation of the cooling capacity of the fixed-frequency air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : A schematic diagram of the connection of a refrigeration circuit in a single refrigeration mode of a fixed-frequency air conditioner provided by the present invention;

[0030] Figure 2 : A schematic diagram of the connection of a refrigeration circuit in a heat pump mode of a fixed-frequency air conditioner provided by the present invention;

[0031] Among them, there are a compressor 1, a condenser 2, an electronic expansion valve 3, an evaporator 4, a condensing fan 5, an evaporating fan 6, a four-way valve 7, and a solenoid valve 8.

[0032] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0034] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0037] The present invention provides a method for adjusting the cooling capacity of a fixed-frequency air conditioner and a fixed-frequency air conditioner. Taking a fixed-frequency air conditioner on a rail vehicle as an example, the technical solution of the present invention is introduced.

[0038] The refrigeration circuit of the fixed frequency air conditioner includes the main refrigeration circuit and the hot gas bypass circuit. Figure 1 As shown, for a single cooling (heating) fixed-frequency air conditioner, the refrigeration main circuit includes a compressor 1, a condenser 2, a throttling device, and an evaporator 4 connected in sequence through pipelines, wherein a condensing fan 5 is provided at the condenser 2, and an evaporating fan 6 is provided at the evaporator 4, and the heat exchange efficiency of the heat exchanger is heated by the fan. Among them, the compressor 1 is a fixed-frequency compressor, the throttling device can be 3, the maximum opening of the electronic expansion valve 3 is 500 steps, and its opening can be adjusted. The evaporating fan 6 and the condensing fan 5 are adjustable-speed fans, and the air volume of the evaporating fan 6 and the condensing fan 5 is adjusted according to the cooling capacity. According to the cooling capacity demand, the cooling capacity adjustment scenario is expanded by setting a variable-caliber (opening) throttling device and a variable-speed fan, and the adjustment accuracy of the fixed-frequency unit under different temperature conditions is improved.

[0039] One end of the hot gas bypass circuit is connected to the pipeline between the compressor 1 outlet and the condenser 2, and the other end is connected to the pipeline between the electronic expansion valve 3 and the evaporator 4. A solenoid valve 8 is provided on the hot gas bypass circuit to control the on and off of the hot gas bypass circuit. The hot gas bypass circuit is provided between the evaporator inlet and the compressor outlet. A solenoid valve is provided on the hot gas bypass circuit. By controlling the opening of the solenoid valve, the refrigerant flow rate of the hot gas bypass circuit is controlled, thereby controlling the refrigerant flow rate in the refrigeration main circuit, that is, controlling the refrigeration capacity.

[0040] like Figure 2 As shown, for the heat pump mode fixed frequency air conditioner, the refrigeration main circuit also includes a four-way valve 7, the compressor 1, the four-way valve 7, the condenser 2, the electronic expansion valve 3, and the evaporator 4 are connected in sequence through pipelines. By setting the four-way valve 7, the refrigerant flow direction is adjusted to achieve switching between cooling and heating modes.

[0041] One end of the hot gas bypass loop is connected to the pipeline between the compressor 1 outlet and the condenser 2 inlet, and the other end is connected to the pipeline between the electronic expansion valve 3 outlet and the evaporator 4 inlet. Similarly, by controlling the on-off and opening of the solenoid valve, the refrigerant flow in the refrigeration main loop is controlled, that is, the refrigeration capacity is controlled.

[0042] For heat pump air conditioners, the outlet end of the hot gas bypass loop is set at the outlet end of compressor 1. The refrigerant coming out of the evaporator merges with the refrigerant coming out of the hot gas bypass loop and then flows back into compressor 1, thereby unloading part of the refrigeration capacity of the refrigeration system. This cycle is applicable to both refrigeration and heat pump systems.

[0043] The fixed-frequency air conditioner also includes a controller, which pre-stores a method for adjusting the cooling capacity of the fixed-frequency air conditioner and a conventional control method for the operation of the fixed-frequency air conditioner. The controller controls the startup and operation and the operation mode of each component according to the requirements of the control method. According to the cooling capacity adjustment method, the on-off of the bypass valve and the opening of the throttling device and / or the air volume of the fan are adjusted according to the set range conditions to adjust the cooling capacity, so as to achieve stepless regulation of the cooling capacity of the fixed-frequency air conditioner.

[0044] Specifically, the solenoid valve 8 can control the on-off of the hot gas bypass circuit. In this embodiment, the on-off of the solenoid valve 8 and the opening of the solenoid valve are controlled in a conventional manner. In this embodiment, the on-off of the solenoid valve and the opening of the solenoid valve are automatically controlled by the difference between the indoor temperature and the indoor set temperature.

[0045] The opening (caliber) of the electronic expansion valve 3 and the air volume of the fan (including the evaporating fan and the condensing fan) are divided into ranges according to different operating conditions, that is, according to the set range conditions (hereinafter referred to as the set conditions). When the conditions are met, the air volume of the electronic expansion valve 3 and the fan remains unchanged within the range, that is, under the set conditions, the existing holding state is maintained unchanged.

[0046] Taking into account that when the air conditioner is operated in different latitudes and different air pressure environments, different control parameters need to be operated to achieve the same temperature control effect. Therefore, the setting conditions include the latitude information of the fixed-frequency air conditioner. According to the latitude information, the diameter of the electronic expansion valve 3 and the air volume of the fan are adjusted accordingly.

[0047] Similarly, different control parameters need to be run under different humidity conditions, so the set conditions can also include the ambient humidity in the operating environment.

[0048] Specifically, the present invention also provides setting condition parameters to clarify the flow conversion mode and speed change mode. The operating conditions and the adjustment relationship are as follows:

[0049] condition System Status Condition 1: K>x Maximum gear: condensing fan speed m1, evaporating fan speed m2, expansion valve diameter m3 Condition 2: y≤K<x Mid-range: condensing fan speed n1, evaporating fan speed n2, expansion valve diameter n3 Condition 3: z≤K<y Minimum gear: condensing fan speed p1, evaporating fan speed p2, expansion valve diameter p3

[0050] Right now:

[0051] When K>x, the fixed-frequency air conditioner operates at the maximum gear state, wherein the condensing fan speed is m1, the evaporating fan speed is m2, and the throttling device opening is m3;

[0052] When y≤K<x, the fixed-frequency air conditioner operates in a mid-range state, wherein the condensing fan speed is n1, the evaporating fan speed is n2, and the throttling device opening is n3;

[0053] When z≤K<y, the fixed-frequency air conditioner operates in a low-speed state, wherein the condensing fan speed is p1, the evaporating fan speed is p2, and the throttling device opening is p3;

[0054] Where K is the judgment condition value, K = a*K1+b*K2,

[0055] K1 is the first judgment constant, which is related to the latitude and ambient temperature, and its value range is 10 to 60. The higher the latitude and the lower the ambient temperature, the smaller the value of K1.

[0056] K2 is the second judgment constant, which is related to the ambient humidity and the vehicle model, and has a value range of 30 to 90. The lower the humidity and the smaller the compartment, the smaller the K2 value.

[0057] a is a coefficient, and its value range is 0.6 to 0.9, which is set according to usage requirements;

[0058] b is a coefficient, and its value range is 0.2 to 0.5, which is set according to usage requirements;

[0059] x, y, and z are set values, and the range is 32 to 40 for x, 22 to 30 for y, and 10 to 19 for z.

[0060] Furthermore, m, n, and p are positive numbers greater than or equal to zero and are set based on experience, wherein m1>n1>p1, m2>n2>p2, and m2>n2>p2. Specific values ​​are determined based on usage and must meet the operating range requirements of the product.

[0061] For example, when K1=50,

[0062] K2=30,

[0063] a=0.9,

[0064] b = 0.2,

[0065] x=35,

[0066] y=25,

[0067] When z=15,

[0068] Then K=51, condition 1 is met, the state is state 1, and it runs in the maximum gear mode, that is, the condensing fan speed is m1, the evaporating fan speed is m2, and the expansion valve diameter is m3.

[0069] Furthermore, under heat pump conditions, the state of the variable components can also be set according to the range conditions.

[0070] Furthermore, the distinction of range conditions for automatic setting to achieve stepless regulation is considered an extension of this patent.

[0071] In summary, the method for adjusting the cooling capacity of a fixed-frequency air conditioner and the fixed-frequency air conditioner provided by the present invention have the following technical advantages compared with the prior art:

[0072] The invention solves the problem that the fixed-frequency air conditioner in the prior art can only adjust the cooling capacity according to the set temperature and the ambient temperature or adjust the cooling capacity in stages, and realizes real-time adjustment of the cooling capacity according to the operating environment;

[0073] The latitude information is added to the operating environment conditions to solve the impact of different latitudes and environmental pressures on cooling capacity;

[0074] The structure is simple and can realize stepless regulation of the cooling capacity of the fixed-frequency air conditioner.

[0075] As described above, similar technical solutions can be derived from the given solution content. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for adjusting the cooling capacity of a fixed-frequency air conditioner, characterized in that: The fixed-frequency air conditioner includes a main refrigeration circuit and a hot gas bypass circuit, the hot gas bypass circuit is provided with a bypass valve, and the main refrigeration circuit is provided with a throttling device and a fan. The fixed-frequency air conditioner adjusts the on-off of the bypass valve and the opening of the throttling device and / or the air volume of the fan according to the set range conditions to adjust the cooling capacity.

2. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to claim 1, characterized in that: When the predetermined conditions are met, the throttling device and the fan remain unchanged within the range.

3. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to claim 1, characterized in that: The setting condition includes latitude information of the fixed-frequency air conditioner.

4. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to claim 1, characterized in that: The set conditions include ambient humidity.

5. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to claim 1, characterized in that: The main refrigeration circuit comprises a compressor, a condenser, a throttling device and an evaporator which are connected in sequence. One end of the hot gas bypass circuit is connected to the outlet of the compressor, and the other end is connected to the outlet of the electronic expansion valve.

6. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to claim 1, characterized in that: The main refrigeration circuit includes a compressor, a condenser, a throttling device and an evaporator. One end of the hot gas bypass circuit is connected to the pipeline between the compressor outlet and the condenser inlet, and the other end is connected to the pipeline between the evaporator inlet and the throttling device outlet.

7. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to any one of claims 1 to 6, characterized in that: The operating conditions include: When K>x, the fixed-frequency air conditioner operates at the maximum gear state, wherein the condensing fan speed is m1, the evaporating fan speed is m2, and the throttling device opening is m3; When y≤K<x, the fixed-frequency air conditioner operates in a mid-range state, wherein the condensing fan speed is n1, the evaporating fan speed is n2, and the throttling device opening is n3; When z≤K<y, the fixed-frequency air conditioner operates in a low-speed state, wherein the condensing fan speed is p1, the evaporating fan speed is p2, and the throttling device opening is p3; Where K is the judgment condition value, K = a*K1+b*K2, K1 is the first judgment constant, which is related to latitude and ambient temperature, and its value range is 10 to 60; K2 is the second judgment constant, which is related to the ambient humidity and vehicle type, and its value range is 30 to 90; a is a coefficient, and its value range is 0.6 to 0.9, which is set according to usage requirements; b is a coefficient, and its value range is 0.2 to 0.5, which is set according to usage requirements; x, y, and z are set values. x is in the range of 32 to 40, y is in the range of 22 to 30, and z is in the range of 10 to 19.

8. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to claim 7, characterized in that: The higher the latitude and the lower the ambient temperature, the smaller the K1 value.

9. A method for adjusting the cooling capacity of a fixed-frequency air conditioner according to claim 7, characterized in that: The lower the humidity and the smaller the compartment, the smaller the K2 value.

10. A fixed-frequency air conditioner, characterized in that: It includes a controller, a main refrigeration circuit and a hot gas bypass circuit, the hot gas bypass circuit is provided with a bypass valve, the main refrigeration circuit is provided with a throttling device and a fan, and a fixed-frequency air conditioning refrigeration capacity adjustment method as described in any one of claims 1 to 9 is preset in the controller.

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