A low-temperature and low-humidity air conditioning device

Abstract

The present invention discloses a low-temperature and low-humidity air-conditioning device, which includes a compressor, a condenser, a condensing fan, a liquid storage device, a first throttling element, a second throttling element, a first evaporator, a second evaporator, an evaporating fan, a gas-liquid separator, a plurality of temperature sensors and a pipe system. The first evaporator and the second evaporator are respectively composed of a supercooling pipe family and an evaporating pipe family, and the supercooling pipe family is evenly distributed in the middle of the evaporating pipe family. The liquid storage device is divided into two routes, the first route passes through the supercooling pipe family of the second evaporator, the first throttling element, and the evaporating pipe family of the first evaporator to the gas-liquid separator; the second route passes through the supercooling pipe family of the first evaporator, the second throttling element, and the evaporating pipe family of the second evaporator to the gas-liquid separator. During operation, the first throttling element and the second throttling element are controlled to realize the alternating operation of the first evaporator and the second evaporator. The present invention adopts a unique design and can be widely used in air-conditioning projects with multi-stage refrigeration.

Description

Technical Field

[0001] The invention relates to the field of special refrigeration equipment, in particular to a low-temperature and low-humidity air-conditioning device. Background Art

[0002] With the rapid development of special refrigeration equipment, the environmental protection requirements for special cabins are increasing. For example, the air supply temperature of air conditioners is required to be lower and lower, and the temperature and humidity fluctuation range is required to be smaller and smaller, which brings about various changes in refrigeration solutions, resulting in oversized equipment and complex electronic control solutions.

[0003] At present, most refrigeration solutions used for aircraft air-conditioning vehicles and cylinder support air-conditioning vehicles often adopt a fresh air multi-stage refrigeration method, which cools high-temperature and high-humidity air (such as dry-bulb temperature 40°C and relative humidity 60%) in stages to low-temperature and low-humidity air (such as dry-bulb temperature 5°C and relative humidity 50%) and sends it to the cooled object. As the air temperature becomes lower, frosting is inevitable in the final stage of vapor compression refrigeration due to the evaporation temperature below 0°C. When the frosting becomes more and more serious, the final stage of refrigeration has to be stopped, resulting in drastic fluctuations in parameters such as the supply air temperature. At present, there are four common practices: ① Add one more stage of final refrigeration, and the evaporator part is connected in series in one air duct for standby switching. This practice requires adding a set of compressors and condensing units, and also requires adding defrosting measures such as electric heating; ② Add one more stage of final refrigeration, and the evaporator part is connected in parallel, distributed in two air ducts, and switched with air valves. This practice not only adds a set of compressors and condensing units, but also adds a set of air ducts, air valves, electric heating and other defrosting measures; ③ The final stage of refrigeration is not increased, and a "double evaporator" is used, that is, an evaporator for normal refrigeration, and the other is equivalent to a subcooler of the condenser. In order to achieve alternating operation, it is usually necessary to control 8 solenoid valves and 2 one-way valves to work, which increases the difficulty of control and reduces the reliability of the product. At the same time, there are drastic changes in the refrigerant during the alternating process; ④ Add rotary dehumidification, liquid dehumidification and solid dehumidification devices in the previous stages, but it is often difficult to achieve due to factors such as volume and air tightness.

[0004] Another application scenario is: for freezing and refrigerating areas for vegetables, meat, etc., or for low-temperature storage of special materials, cold air air conditioners are used. The space temperature needs to be controlled at a low temperature, such as -25℃~8℃. Even if a single-stage system is used, there is still frosting on the evaporator, which requires defrosting. The traditional approach is the same as above and is also difficult to implement. Summary of the invention

[0005] The object of the present invention is to provide a low-temperature and low-humidity air-conditioning device to solve the problem of easy frost formation on the evaporator of the prior art special air-conditioning equipment.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A low-temperature and low-humidity air conditioning device, characterized in that it includes a compressor, a condenser with a condensing fan, a liquid storage device, a first throttling element, a second throttling element, a first evaporator, a second evaporator, an evaporating fan, and a gas-liquid separator, wherein:

[0008] The first evaporator and the second evaporator have the same structure, and each of them includes a subcooling tube group and an evaporation tube group, and the subcooling tube groups in the first evaporator and the second evaporator are evenly distributed in the middle of the corresponding evaporation tube group, and the first evaporator, the second evaporator, and the evaporation fan are arranged in the air duct according to the wind direction, and the first evaporator and the second evaporator share the evaporation fan;

[0009] The refrigerant outlet end of the compressor is connected to the inlet end of the condenser through a pipeline, the outlet end of the condenser is connected to the inlet end of the liquid reservoir through a pipeline, the outlet end of the liquid reservoir is connected to two pipelines, the first pipeline of the liquid reservoir outlet end is connected to the inlet end of the subcooling tube family of the second evaporator, the subcooling tube family outlet end of the second evaporator is connected to the inlet end of the first throttling element through a pipeline, the first throttling element outlet end is connected to the inlet end of the evaporation tube family of the first evaporator through a pipeline, and the evaporation tube family outlet end of the first evaporator is connected to the inlet end of the gas-liquid separator through a pipeline; the second pipeline of the liquid reservoir outlet end is connected to the inlet end of the subcooling tube family of the first evaporator, the subcooling tube family outlet end of the first evaporator is connected to the inlet end of the second throttling element through a pipeline, the second throttling element outlet end is connected to the inlet end of the evaporation tube family of the second evaporator through a pipeline, and the evaporation tube family outlet end of the second evaporator is connected to the inlet end of the gas-liquid separator through a pipeline;

[0010] The outlet end of the gas-liquid separator is connected to the refrigerant return end of the compressor through a pipeline, and the above structure constitutes a refrigerant circulation loop.

[0011] The low-temperature and low-humidity air-conditioning device is characterized in that it also includes a temperature sensor group and a humidity sensor group. The temperature sensor group includes a temperature sensor installed at the first evaporator evaporation tube family, a temperature sensor installed at the second evaporator evaporation tube family, a temperature sensor installed at the air inlet of the air duct, and a temperature sensor installed at the air outlet of the air duct; the humidity sensor group includes a humidity sensor installed at the air inlet of the air duct, and a humidity sensor installed at the air outlet of the air duct; each temperature sensor corresponds to monitoring the temperature of the first evaporator evaporation tube family, the temperature of the second evaporator evaporation tube family, the inlet temperature, and the outlet temperature, and each humidity sensor corresponds to monitoring the inlet humidity and the outlet humidity, and each temperature sensor and humidity sensor are respectively connected to an external controller, and the external controller is respectively connected to the first throttling element and the second throttling element for control, and the external sensor controls the operation of the first throttling element and the second throttling element based on temperature and humidity data.

[0012] The low-temperature and low-humidity air-conditioning device is characterized in that the first evaporator and the second evaporator are both fin-tube heat exchangers composed of a subcooling tube family and an evaporating tube family. The first evaporator and the second evaporator have the same specifications and structures, and the number of subcooling tube families in the first evaporator and the second evaporator is smaller than that in the evaporating tube family.

[0013] The low-temperature and low-humidity air-conditioning device is characterized in that the first throttling element and the second throttling element are electronic expansion valves of the same model and specification, and are fully closed when not working.

[0014] The low-temperature and low-humidity air-conditioning device is characterized in that the first throttling element and the second throttling element can be replaced by a combination structure of a thermal expansion valve and a normally closed solenoid valve.

[0015] The low-temperature and low-humidity air-conditioning device is characterized in that the evaporating fan is a high-pressure fan, and whether the evaporating fan works in a blowing or suction mode depends on the specific situation.

[0016] When the present invention is working, the first throttling element and the second throttling element are controlled to open by an external controller, so as to realize the alternating operation of the first evaporator and the second evaporator. The technology can be used in the last stage of multi-stage refrigeration.

[0017] The first evaporator and the second evaporator use fin-tube heat exchangers of the same size and specification, including the subcooling tube family and the evaporation tube family using exactly the same design. Similarly, the first throttling element and the second throttling element use the same model. This design greatly simplifies the parameters and software programs that need to be controlled.

[0018] The distributor, branch number, row number, column number, tube diameter, fin and manifold involved in the evaporator tube group are all normal air conditioning designs. The only difference is that several tube groups are reserved in the middle as subcooling tube groups. Since the actual frost is more serious at the lower part of the evaporator, in order to improve the defrosting effect, the number of subcooling tube groups at the lower part can be appropriately increased. The design of the subcooling tube group is to meet the defrosting time on the one hand, and to increase the subcooling degree of the refrigerant on the other hand to increase the cooling capacity. There is also a way to insert an electric heating tube at the position of the subcooling tube group to achieve this, but this is not an energy-saving approach.

[0019] When the first evaporator is working at low temperature, the fins of the first evaporator will be frosted due to the influence of air humidity and evaporation temperature. At the same time, the temperature change of the evaporation tube family temperature sensor of the first evaporator is monitored. When it cannot maintain normal operation, the second throttling element is opened and the first throttling element is closed, that is, the first evaporator stops working and the second evaporator starts working. When the second evaporator is working at low temperature, the temperature change of the evaporation tube family temperature sensor of the second evaporator is monitored to decide whether to switch again.

[0020] When the first throttling element is working and the second throttling element is not working, the high-pressure refrigerant in the subcooling tube group of the first evaporator is in a cut-off state, and the refrigeration effect on the first evaporator is extremely small and can be ignored, and vice versa.

[0021] The heat exchange capacity of the evaporation tube group in the first and second evaporators is designed based on the inlet air temperature (such as lower than 15°C), the outlet air temperature (such as lower than 8°C) and the dehumidification requirements; the subcooling tube group is designed based on its defrosting time being shorter than the frost time of the evaporation tube group.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention adopts an evaporator combining two groups of subcooling tube families and evaporation tube families, which reduces equipment investment and can solve the problem of evaporator frosting through reliable alternating work, thereby greatly improving the efficiency of the equipment.

[0024] 2. The present invention effectively reduces the dramatic changes in air supply temperature and humidity caused by factors such as compressor shutdown, and can achieve a dry-bulb temperature fluctuation of 3.5°C and a relative humidity of less than 15%.

[0025] 3. The present invention can be conveniently placed in multi-stage refrigeration air conditioning projects and has strong promotion potential.

[0026] 4. The invention has mature technology, simple process and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the system principle of the present invention.

[0028] Figure 2 It is a schematic diagram of the evaporator distribution of the present invention.

[0029] Explanation of the numbers in the figure: 1-compressor, 2-condenser, 3-condensing fan, 4-liquid storage tank, 5-first throttling element, 6-second throttling element, 7-first evaporator (7.1-subcooling tube family, 7.2-evaporation tube family), 8-second evaporator (8.1-subcooling tube family, 8.2-evaporation tube family), 9-evaporation fan, 10-gas-liquid separator. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0031] like Figure 1 , Figure 2 As shown in the figure is the air flow direction, The present invention provides a low-temperature and low-humidity air-conditioning device, comprising a compressor 1, a condenser 2 with a condensing fan 3, a liquid storage device 4, a first throttling element 5, a second throttling element 6, a first evaporator 7, a second evaporator 8, an evaporating fan 9, and a gas-liquid separator 10, wherein:

[0032] The first evaporator 7 and the second evaporator 8 have the same structure, and each includes a subcooling tube group and an evaporation tube group, and the subcooling tube groups in the first evaporator 7 and the second evaporator 8 are evenly distributed in the middle of the corresponding evaporation tube group, and the first evaporator 7, the second evaporator 8, and the evaporation fan 9 are arranged in the air duct according to the wind direction, and the first evaporator 7 and the second evaporator 8 share the evaporation fan 9;

[0033] The refrigerant outlet of the compressor 1 is connected to the inlet of the condenser 2 through a pipeline, the outlet of the condenser 2 is connected to the inlet of the liquid reservoir 4 through a pipeline, the outlet of the liquid reservoir 4 is connected to two pipelines, the first pipeline of the outlet of the liquid reservoir 4 is connected to the inlet of the subcooling tube group 8.1 of the second evaporator 8, the outlet of the subcooling tube group 8.1 of the second evaporator 8 is connected to the inlet of the first throttling element 5 through a pipeline, the outlet of the first throttling element 5 is connected to the inlet of the evaporation tube group 7.2 of the first evaporator 7 through a pipeline, and the first The outlet end of the evaporation tube group 7.2 of the evaporator 7 is connected to the inlet end of the gas-liquid separator 10 through a pipeline; the second pipeline of the outlet end of the liquid storage 4 is connected to the inlet end of the subcooling tube group 7.1 of the first evaporator 7, the outlet end of the subcooling tube group 7.1 of the first evaporator 7 is connected to the inlet end of the second throttling element 6 through a pipeline, the outlet end of the second throttling element 6 is connected to the inlet end of the evaporation tube group 8.2 of the second evaporator 8 through a pipeline, and the outlet end of the evaporation tube group 8.2 of the second evaporator 8 is connected to the inlet end of the gas-liquid separator 10 through a pipeline;

[0034] The outlet end of the gas-liquid separator 10 is connected to the refrigerant return end of the compressor 1 through a pipeline, and the above structure constitutes a refrigerant circulation loop.

[0035] It also includes a temperature sensor group and a humidity sensor group. The temperature sensor group includes a temperature sensor T1 installed at the evaporation tube family 7.2 of the first evaporator 7, a temperature sensor T2 installed at the evaporation tube family 8.2 of the second evaporator 8, a temperature sensor T3 installed at the air inlet of the air duct, and a temperature sensor T4 installed at the air outlet of the air duct; the humidity sensor group includes a humidity sensor H3 installed at the air inlet of the air duct, and a humidity sensor H4 installed at the air outlet of the air duct; each temperature sensor T1-T4 corresponds to monitoring the temperature of the evaporation tube family 7.2 of the first evaporator 7, the temperature of the evaporation tube family 8.2 of the second evaporator 8, the air inlet temperature, and the air outlet temperature, and each humidity sensor H1 and H2 corresponds to monitoring the air inlet humidity and the air outlet humidity, and each temperature sensor and humidity sensor are respectively connected to an external controller, and the external controller is respectively connected to the first throttling element 5 and the second throttling element 6, and the external sensor controls the operation of the first throttling element 5 and the second throttling element 6 based on temperature and humidity data.

[0036] When the first evaporator 7 works at low temperature, the fins of the first evaporator 7 are frosted due to the influence of air humidity and evaporation temperature. At the same time, the temperature change of the evaporation tube group 7.2 temperature sensor T1 of the first evaporator 7 is monitored. When it cannot maintain normal operation, the second throttling element 6 is opened and the first throttling element 5 is closed, that is, the first evaporator 7 stops working, and the second evaporator 8 starts working. When the second evaporator 8 works at low temperature, the temperature change of the evaporation tube group 8.2 temperature sensor T2 of the second evaporator 8 is monitored to decide whether to switch again.

[0037] The heat exchange capacity of the evaporation tube groups 7.2 and 8.2 is designed based on the inlet air temperature (e.g., lower than 15°C), the outlet air temperature (e.g., lower than 8°C) and the dehumidification requirements; the subcooling tube groups 7.1 and 8.1 are designed based on their defrosting time being shorter than the frosting time of the evaporation tube groups 7.2 and 8.2, and their tube group quantity is much lower than that of the evaporation tube groups 7.2 and 8.2.

[0038] The first throttling element 5 and the second throttling element 6 are electronic expansion valves of the same model and specification, which are fully closed when not in operation. However, it is not excluded that a thermal expansion valve and a normally closed solenoid valve may be used in combination to replace the electronic expansion valve.

[0039] The evaporating fan 9 is usually a high-pressure fan, and whether it is a blowing or suction form depends on the specific situation.

[0040] like Figure 2The figure shows one of the distribution examples of the first evaporator 7 and the second evaporator 8 of the present invention. The evaporation tube groups 7.2 and 8.2 include distributors, branch numbers, rows, columns, tube diameters, fins and manifolds, etc., which are determined according to requirements during specific design. The only difference is that several tube groups are reserved in the middle as the subcooling tube groups 7.1 and 8.1. Since the actual evaporator is more seriously frosted toward the lower part, in order to improve the defrosting effect, the number of subcooling tube groups 7.1 and 8.1 in the lower part can be appropriately increased. The design of the subcooling tube groups 7.1 and 8.1 is to meet the defrosting time on the one hand, and to increase the subcooling degree of the refrigerant on the other hand to increase the cooling capacity. There is also a way to insert electric heating tubes at the positions of the subcooling tube groups 7.1 and 8.1 to achieve this, but this is not an energy-saving approach.

[0041] Further explanation:

[0042] The first evaporator 7 and the second evaporator 8 use fin-tube heat exchangers of the same size and specifications, including subcooling tube groups 7.1 and 8.1, and the evaporation tube groups 7.2 and 8.2 use exactly the same design. Similarly, the first throttling element 5 and the second throttling element 6 use the same model. This design greatly simplifies the parameters and software programs that need to be controlled.

[0043] When the first throttling element 5 is working and the second throttling element 6 is not working, the high-pressure refrigerant in the subcooling tube group 7.1 of the first evaporator 7 is in a cut-off state, and the influence on the refrigeration of the first evaporator 7 is extremely small and can be ignored, and vice versa.

[0044] In addition, the inlet air temperature shown in the figure is collected by the temperature sensor T3, and the outlet air temperature is collected by the temperature sensor T4. Corresponding humidity sensors H3 and H4 can also be set as needed and participate in related controls, which will not be further elaborated here.

[0045] The embodiments described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have all been recorded in the claims.

Claims

1. A low temperature and low humidity air conditioning device, characterized in that: The invention comprises a compressor, a condenser with a built-in condensing fan, a liquid reservoir, a first throttling element, a second throttling element, a first evaporator, a second evaporator, an evaporating fan, and a gas-liquid separator, wherein: the first evaporator and the second evaporator have the same structure, each comprising a subcooling tube family and an evaporating tube family, and the subcooling tube families in the first evaporator and the second evaporator are respectively evenly distributed in the middle of the corresponding evaporating tube family, the first evaporator, the second evaporator, and the evaporating fan are arranged in an air duct according to wind direction, and the first evaporator and the second evaporator share the evaporating fan; the refrigerant outlet end of the compressor is connected to the inlet end of the condenser through a pipeline, the outlet end of the condenser is connected to the inlet end of the liquid reservoir through a pipeline, the outlet end of the liquid reservoir is connected to two pipelines, the first pipeline at the outlet end of the liquid reservoir is connected to the inlet end of the second evaporator The inlet end of the cold pipe family and the outlet end of the subcooling pipe family of the second evaporator are connected to the inlet end of the first throttling element through a pipeline, the outlet end of the first throttling element is connected to the inlet end of the evaporation pipe family of the first evaporator through a pipeline, and the outlet end of the evaporation pipe family of the first evaporator is connected to the inlet end of the gas-liquid separator through a pipeline; the second pipeline of the liquid storage outlet end is connected to the inlet end of the subcooling pipe family of the first evaporator, the outlet end of the subcooling pipe family of the first evaporator is connected to the inlet end of the second throttling element through a pipeline, the outlet end of the second throttling element is connected to the inlet end of the evaporation pipe family of the second evaporator through a pipeline, and the outlet end of the evaporation pipe family of the second evaporator is connected to the inlet end of the gas-liquid separator through a pipeline; the outlet end of the gas-liquid separator is connected to the refrigerant return end of the compressor through a pipeline, and the above structure constitutes a refrigerant circulation loop; The low-temperature and low-humidity air-conditioning device further comprises a temperature sensor group and a humidity sensor group. The temperature sensor group comprises a temperature sensor installed at the evaporation tube family of the first evaporator, a temperature sensor installed at the evaporation tube family of the second evaporator, a temperature sensor installed at the air inlet of the air duct, and a temperature sensor installed at the air outlet of the air duct; the humidity sensor group comprises a humidity sensor installed at the air inlet of the air duct, and a humidity sensor installed at the air outlet of the air duct; each temperature sensor corresponds to monitoring the temperature of the evaporation tube family of the first evaporator, the temperature of the evaporation tube family of the second evaporator, the air inlet temperature, and the air outlet temperature, and each humidity sensor corresponds to monitoring the air inlet humidity and the air outlet humidity, and each temperature sensor and humidity sensor are respectively connected to an external controller, and the external controller is respectively connected to the first throttling element and the second throttling element for control, and the external sensor controls the operation of the first throttling element and the second throttling element based on the temperature and humidity data; The first evaporator and the second evaporator are both fin-tube heat exchangers composed of a subcooling tube group and an evaporating tube group. The first evaporator and the second evaporator have the same specifications and structures. The number of subcooling tube groups in each of the first evaporator and the second evaporator is smaller than that of the evaporating tube group.

2. A low temperature and low humidity air conditioning device according to claim 1, characterized in that: The first throttling element and the second throttling element are electronic expansion valves of the same model and specification, and are fully closed when not in operation.

3. A low temperature and low humidity air conditioning device according to claim 1 or 2, characterized in that: The first throttling element and the second throttling element can both be replaced by a combination structure of a thermal expansion valve and a normally closed solenoid valve.

4. A low temperature and low humidity air conditioning device according to claim 1, characterized in that: The evaporation fan is a high-pressure fan, and whether the evaporation fan works in a blowing or suction mode depends on specific circumstances.

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