1. The utility model provides an ultra-low temperature forced air cooling module machine system which characterized in that: the system comprises a four-way valve (1) and a main loop (2), wherein the main loop (2) comprises a first pipeline (21) and a second pipeline (22), the four-way valve comprises a port C, a port D, a port E and a port S, one end of the first pipeline (21) is communicated with the port C of the four-way valve, the other end of the first pipeline is connected with the port E of the four-way valve, the first pipeline (21) is sequentially provided with a cavity connected with one side of a finned tube type heat exchanger (3), a condensation side of an economizer (4) and a water side heat exchanger (5), one end of the second pipeline is communicated with the port S of the four-way valve, the other end of the second pipeline is communicated with the port D of the four-way valve, and a gas and enthalpy adding compressor (6) is arranged on the second pipeline;

and a reservoir (7) is arranged on an input pipeline (215) of the main loop connected with the economizer (4), and two ends of the reservoir (7) are connected in parallel with a protection pipeline (23) for protecting the fin tube type heat exchanger (3).

2. An ultra-low temperature air-cooled modular machine system as claimed in claim 1, wherein: the first pipeline (21) of the main loop comprises a check valve group, one end interface of the finned tube type heat exchanger (3) is communicated with a port C of the four-way valve through a pipeline, the other end interface of the finned tube type heat exchanger is communicated with the check valve group through a first connecting pipeline (211), and the check valve group is further connected with the water side heat exchanger (5) through a second connecting pipeline (212);

the check valve group comprises a third connecting pipeline (213) and a fourth connecting pipeline (214), the third connecting pipeline (213) is connected with the fourth connecting pipeline (214) in parallel, the third connecting pipeline (213) and the fourth connecting pipeline (214) are connected with the first connecting pipeline (211) through a first three-way valve at one end close to the first connecting pipeline (211), and the third connecting pipeline (213) and the fourth connecting pipeline (214) are connected with the second connecting pipeline (212) through a second three-way valve at one end close to the second connecting pipeline (212);

a pair of one-way valves I (2131) are arranged on the connecting pipeline III (213), a three-way valve III (2132) is arranged on the pipeline connected between the pair of one-way valves I, one end, far away from the economizer (4), of the input pipeline (215) is communicated with the three-way valve III (2132), the liquid flow direction in the one-way valve I (2131) is the same as that of the input pipeline (215), and a filter is further arranged on the input pipeline (215);

the connecting pipe is provided with a pair of one-way valves II (2141) on the connecting pipe IV (214), the pipeline of the connection between the pair of one-way valves II (2141) is provided with a three-way valve IV (2142), the three-way valve IV (2142) is connected with the output interface of the condenser side of the economizer (4) through an output pipe (216), the liquid flow direction in the one-way valve II is the same as that of the output pipe (216), and the output pipe is provided with a main loop electronic expansion valve (217).

3. An ultra-low temperature air-cooled modular machine system as claimed in claim 1, wherein: a fin temperature sensor is arranged on the outer side of the fin tube type heat exchanger (3), a multi-layer heat exchange loop (31) is arranged in the fin tube type heat exchanger (3), the heat exchange loop is communicated with the main loop, and a liquid separator (32) is arranged at the input end of the heat exchange loop;

the upper side of the finned tube heat exchanger (3) is provided with a fan (8), and the end part of the finned tube heat exchanger (3) is provided with a gas collecting pipe connected with a pipeline from the port C of the four-way valve.

4. An ultra-low temperature air-cooled modular machine system as claimed in claim 3, wherein: the bottom of the fin tube type heat exchanger (3) is also provided with a superheating pipeline (34), a protection pipeline (23) connected with the main loop comprises a first protection pipeline (231) and a second protection pipeline (232), one end of the first protection pipeline (231) is connected with the input end of the superheating pipeline (34), and the other end of the first protection pipeline is provided with a three-way valve five-way connection pipeline connected with the input end of the liquid reservoir (7); and one end of the second protection pipeline (232) is communicated with the output end of the overheating pipeline, and the other end of the second protection pipeline is provided with a three-way valve six which is communicated with the output end pipeline of the liquid storage device (7).

5. An ultra-low temperature air-cooled modular machine system as claimed in claim 2, wherein: a needle valve III (2111) for statically filling refrigerant is arranged on the connecting pipeline I (211), and a needle valve IV (2161) for vacuumizing is also arranged on the output pipeline (216); the input end pipeline of the air-supplying enthalpy-increasing compressor (6) is provided with a first needle valve, and the output pipeline is provided with a second needle valve.

6. An ultra-low temperature air-cooled modular machine system as claimed in claim 2, wherein: including ambient temperature sensor, still be connected with on the input pipeline of major loop and assist return circuit (9), assist the opposite side cavity back of return circuit other end connection economic ware (4) and be connected with tonifying qi booster compressor (6), assist the return circuit and be provided with on the pipeline that major loop and economic ware (4) are connected and assist return circuit electronic expansion valve (91) and evaporating temperature sensor (92), it is provided with exhaust temperature sensor (93) on the pipeline that economic ware (4) and tonifying qi booster compressor (6) are connected to assist the return circuit.

7. An ultra-low temperature air-cooled modular machine system as claimed in claim 2, wherein: and a gas-liquid separator (221) is further arranged on the pipeline of the four-way valve S port connected with the gas supplementing booster compressor (6) of the pipeline two (22), a gas suction temperature sensor (222) and a low pressure sensor (223) are further arranged on the pipeline of the four-way valve S port connected with the gas-liquid separator, and an exhaust temperature sensor (225) and a high pressure sensor (226) are arranged on the pipeline of the four-way valve D port connected with the gas supplementing booster compressor (6).

Background

At present, the ultra-low temperature air-cooling module unit is widely applied to northern areas, but the northern areas often have heavy snow or even snowstorm weather in winter, and the northern areas have rain and snow weather in early winter, which is quite unfavorable for the fin tube type heat exchanger on the ultra-low temperature unit to exchange heat with air, especially on the surface of the fin tube type heat exchanger, a large amount of snow is absorbed on the surface of the fin tube type heat exchanger due to the suction effect of an axial flow fan, the unit defrosts when the environmental temperature is low, the defrosting water close to the surface of the fin is mixed with the snow absorbed on the outermost layer of the surface of the fin in the process of discharging the defrosting water from the fin, so that the bottom of the coil is frozen, the defrosting water channel of the fin tube type heat exchanger is completely blocked after the defrosting water at the bottom of the fin tube type heat exchanger is frozen, and the defrosting water in each unit defrosting process cannot be discharged and only can be accumulated to the frozen part at the bottom of the fin tube type heat exchanger for a long time and is frozen to be thicker, and extend higher and higher along the height direction of the coil: on one hand, the windward channel on the surface of the finned tube heat exchanger is reduced, the heat exchange capacity of a refrigerant and the air side is poor, the power consumption of a motor in an axial flow fan is increased, the heat dissipation of the fan motor is easy to frequently generate heat overload, and the refrigerant leakage is possibly caused by flattening the heat exchange tubes in the finned tube heat exchanger after the bottom ice layer reaches a certain thickness; on the other hand, the electronic expansion valve of the main loop fluctuates seriously, the suction superheat degree of the compressor also fluctuates along with the fluctuation seriously to cause the liquid return or oil shortage of the compressor, the compression ratio of the system is increased, the exhaust temperature is increased, the working environment of a motor in the compressor is deteriorated, the lubrication between a bearing and a crankshaft and the sealing performance between a movable scroll and a fixed scroll are poor, and even the high-temperature carbonization and decomposition of the refrigeration oil are caused.

Disclosure of Invention

In view of the above, the present invention is directed to an ultra-low temperature air-cooled modular machine system, in which a main loop reservoir is connected in parallel with a protection pipeline for a fin-tube heat exchanger to perform overheating and supercooling temperature rise, so that even if the surface of the bottom of the fin-tube heat exchanger is frozen in winter, smooth circulation of defrosting water can be ensured, stable operation of the system is ensured, and the service life of each component is prolonged.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

an ultra-low temperature air-cooled module machine system comprises a four-way valve and a main loop, wherein the main loop comprises a first pipeline and a second pipeline, the four-way valve comprises a port C, a port D, a port E and a port S, one end of the first pipeline is communicated with the port C of the four-way valve, the other end of the first pipeline is connected with the port E of the four-way valve, the first pipeline is sequentially provided with a finned tube type heat exchanger, an economizer condensation side and a water side heat exchanger side chamber, one end of the second pipeline is communicated with the port S of the four-way valve, the other end of the second pipeline is communicated with the port D of the four-way valve, and an air-supplying and enthalpy-increasing compressor is arranged on the second pipeline;

and a reservoir is arranged on an input pipeline of the main loop connected with the economizer, and two ends of the reservoir are connected in parallel with a protection pipeline for protecting the finned tube heat exchanger.

Furthermore, a first pipeline of the main loop comprises a check valve group, a port at one end of the finned tube type heat exchanger is communicated with a port C of the four-way valve through a pipeline, a port at the other end of the finned tube type heat exchanger is communicated with the check valve group through a first connecting pipeline, and the check valve group is also connected with the water side heat exchanger through a second connecting pipeline;

the check valve group comprises a third connecting pipeline and a fourth connecting pipeline, the third connecting pipeline is connected with the fourth connecting pipeline in parallel, one ends of the third connecting pipeline and the fourth connecting pipeline, which are close to the first connecting pipeline, are connected with the first connecting pipeline through a first three-way valve, and one ends of the third connecting pipeline and the fourth connecting pipeline, which are close to the second connecting pipeline, are connected with the second connecting pipeline through a second three-way valve;

a pair of one-way valves I is arranged on the connecting pipeline III, a three-way valve III is arranged on the pipeline connected between the pair of one-way valves I, one end, far away from the economizer, of the input pipeline is communicated with the three-way valve III, the liquid flow direction in the one-way valves I is the same as that of the input pipeline, and a filter is further arranged on the input pipeline;

the fourth connecting pipeline is provided with a second pair of one-way valves, the fourth connecting pipeline connected between the second pair of one-way valves is provided with a fourth three-way valve, the fourth three-way valve is connected with an output interface of the condenser side of the economizer through an output pipeline, the liquid flow direction in the second one-way valve is the same as that of the output pipeline, and the output pipeline is provided with a main loop electronic expansion valve.

Furthermore, a fin temperature sensor is arranged on the outer side of the fin tube type heat exchanger, a plurality of layers of heat exchange loops are arranged in the fin tube type heat exchanger, the heat exchange loops are communicated with the main loop, and a liquid separator is arranged at the input end of each heat exchange loop;

and a fan is arranged on the upper side of the finned tube heat exchanger, and a gas collecting pipe arranged at the end part of the finned tube heat exchanger is connected with a pipeline coming out from a port C of the four-way valve.

Furthermore, a superheating pipeline is further arranged at the bottom of the fin tube type heat exchanger, the pipeline connected with the main loop comprises a first protection pipeline and a second protection pipeline, one end of the first protection pipeline is connected with the input end of the superheating pipeline, and the other end of the first protection pipeline is provided with a three-way valve five which is connected to the pipeline at the input end of the liquid reservoir; and one end of the protection pipeline II is communicated with the output end of the overheating pipeline, and the other end of the protection pipeline II is provided with a three-way valve VI which is communicated with the pipeline at the output end of the liquid storage device.

Furthermore, a needle valve III for statically filling a refrigerant is arranged on the connecting pipeline I, and a needle valve IV for vacuumizing is also arranged on the output pipeline; the input end pipeline of the air-supplying enthalpy-increasing compressor is provided with a first needle valve, and the output pipeline is provided with a second needle valve.

Further, including ambient temperature sensor, still be connected with the auxiliary circuit on the input pipeline of major loop, be connected with tonifying qi booster compressor behind the opposite side cavity of economizer is connected to the auxiliary circuit other end, be provided with auxiliary circuit electronic expansion valve and evaporating temperature sensor on the pipeline that major loop and economizer are connected in the auxiliary circuit, the auxiliary circuit is provided with exhaust temperature sensor on the pipeline that economizer and tonifying qi booster compressor are connected.

Furthermore, a gas-liquid separator is further arranged on a pipeline of the second pipeline, wherein the pipeline is connected with the gas supplementing booster compressor through an S port of the four-way valve, an air suction temperature sensor and a low pressure sensor are further arranged on the pipeline, which is connected with the gas-liquid separator, through the S port of the four-way valve, and an exhaust temperature sensor and a high pressure sensor are arranged on the pipeline, which is connected with the gas supplementing booster compressor through a D port of the four-way valve.

Compared with the prior art, the ultralow temperature air-cooled module machine system has the following beneficial effects:

(1) the main loop is provided with the liquid storage device which is connected with the preheating pipeline at the bottom of the fin tube type heat exchanger in parallel, so that even if the surface of the bottom of the fin tube type heat exchanger is frozen in winter, the smooth circulation of defrosting water can be ensured, the stable operation of the system is ensured, and the service life of each part is prolonged.

(2) The compressor air suction temperature sensor and the low-pressure sensor are arranged on a pipeline from the four-way valve to the gas-liquid separator instead of a pipeline from the gas-liquid separator to the air return port of the compressor, so that the problems that the control of a main loop electronic expansion valve is unstable and the fluctuation of the opening degree and the superheat degree of a main valve is large due to resistance loss in the gas-liquid separator can be avoided, the stable control of the main loop electronic expansion valve is ensured, and the stability of a system is improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view of an ultra-low temperature air-cooled modular machine system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the working principle of a finned tube heat exchanger according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a finned tube heat exchanger according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of an economizer downstream liquid draw mode of the auxiliary loop according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a manner of taking liquid from the bottom of the reservoir in the auxiliary circuit according to the embodiment of the present invention.

Description of reference numerals:

1-a four-way valve; 2-the main loop; 21-pipeline one; 211-connecting the first pipe; 2111-needle valve III: 212-connecting conduit two; 213-connecting a third pipeline; 2131-Single valve one; 2132 three-way valve III; 214-connecting conduit four; 2141-one-way valve two; 2142-three-way valve four; 215 — input pipe; 216-an output conduit; 2161-needle valve IV; 217-main loop electronic expansion valve; 22-line two; 221-a gas-liquid separator; 222-an inspiration temperature sensor; 223-a low pressure sensor; 224-exhaust gas temperature sensor; 225-high pressure sensor; 23-protection of the pipeline; 231-protection pipeline one; 232-protection pipe II; 3-fin tube heat exchanger; 31-a heat exchange loop; 32-a liquid separator; 33-a gas collecting pipe; 34-a superheating circuit; 4-an economizer; 5-a water side heat exchanger; 6-air-supply enthalpy-increasing compressor; 7-a reservoir; 8-a fan; 9-auxiliary loop; 91-auxiliary loop electronic expansion valve; 92-an evaporation temperature sensor; 93-exhaust gas temperature sensor.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

As shown in fig. 1 to 3, an ultra-low temperature air-cooled module machine system comprises a four-way valve 1 and a main loop 2, wherein the main loop 2 comprises a first pipeline 21 and a second pipeline 22, the four-way valve comprises a port C, a port D, a port E and a port S, one end of the first pipeline 21 is communicated with the port C of the four-way valve, the other end of the first pipeline is connected with the port E of the four-way valve, the first pipeline 21 is sequentially provided with a cavity connected with a finned tube heat exchanger 3, a condenser side of an economizer 4 and a water side heat exchanger 5, one end of the second pipeline is communicated with the port S of the four-way valve, the other end of the second pipeline is communicated with the port D of the four-way valve, and a gas-supply enthalpy-increasing compressor 6 is arranged on the second pipeline;

and a reservoir 7 is arranged on an input pipeline 215 of the main loop connected with the economizer 4, and two ends of the reservoir 7 are connected in parallel with a protection pipeline 23 for protecting the fin tube type heat exchanger 3.

The other cavity of the water side heat exchanger 5 is matched with flowing water flows with different temperatures, and is matched with an inlet of the water flows to be provided with an inlet water temperature sensor and an outlet of the water flows to be provided with an outlet water temperature sensor.

As shown in fig. 1 to 3, the first pipeline 21 of the main loop includes a check valve set, one end interface of the finned tube heat exchanger 3 is communicated with a port C of the four-way valve through a pipeline, the other end interface is communicated with the check valve set through a first connecting pipeline 211, and the check valve set is further connected with the water side heat exchanger 5 through a second connecting pipeline 212;

the check valve group comprises a third connecting pipeline 213 and a fourth connecting pipeline 214, the third connecting pipeline 213 is connected with the fourth connecting pipeline 214 in parallel, the third connecting pipeline 213 and the fourth connecting pipeline 214 are connected with the first connecting pipeline 211 through a first three-way valve at one ends close to the first connecting pipeline 211, and the third connecting pipeline 213 and the fourth connecting pipeline 214 are connected with the second connecting pipeline 212 through a second three-way valve at one ends close to the second connecting pipeline 212;

a pair of one-way valves I2131 are arranged on the connecting pipeline III 213, a three-way valve III 2132 is arranged on a pipeline connected between the pair of one-way valves I, one end, far away from the economizer 4, of the input pipeline 215 is communicated with the three-way valve III 2132, the liquid flow direction in the one-way valves I2131 is the same as that of the input pipeline 215, and a filter is further arranged on the input pipeline 215;

a pair of two one-way valves 2141 is arranged on the fourth connecting pipeline 214, a three-way valve 2142 is arranged on a pipeline for connecting the two one-way valves 2141, the four three-way valve 2142 is connected with an output interface of the condenser side of the economizer 4 through an output pipeline 216, the liquid flow direction in the second one-way valve is the same as that of the output pipeline 216, and a main loop electronic expansion valve 217 is arranged on the output pipeline.

As shown in fig. 1 to 3, a fin temperature sensor is arranged outside the fin-tube heat exchanger 3, a multi-layer heat exchange loop 31 is arranged inside the fin-tube heat exchanger 3, the heat exchange loop is communicated with a main loop, and a liquid separator 32 is arranged at an input end of the heat exchange loop;

the upper side of the finned tube heat exchanger 3 is provided with a fan 8, and the two end parts of the finned tube heat exchanger 3 are provided with gas collecting pipes 33 which are connected with a pipeline from a port C of the four-way valve

As shown in fig. 1 to 3, a superheating pipeline 34 is further arranged at the bottom of the fin-tube heat exchanger 3, the protection pipeline 23 connected to the main loop includes a first protection pipeline 231 and a second protection pipeline 232, one end of the first protection pipeline 231 is connected to the input end of the superheating pipeline 34, and the other end of the first protection pipeline is provided with a triple valve five which is connected to the input end pipeline of the reservoir 7; and one end of the second protection pipeline 232 is communicated with the output end of the overheating pipeline, and the other end of the second protection pipeline is provided with a three-way valve six which is communicated with the pipeline at the output end of the liquid storage device 7.

As shown in fig. 1 to fig. 3, a needle valve iii 2111 for statically filling refrigerant is arranged on the first connecting pipe 211, and a needle valve iv 2161 for vacuumizing is further arranged on the output pipe 216; the input end pipeline of the air-supplying enthalpy-increasing compressor 6 is provided with a first needle valve, and the output pipeline is provided with a second needle valve.

Needle valve three 2111 is used for unit static filling refrigerant and fills refrigerant with when compressor 6 does not open, needle valve four 2161 is the unit evacuation, needle valve one and needle valve two are used for initial supplementary refrigerant, also can assist the detection pressure.

As shown in fig. 1 to 3, the auxiliary circuit comprises an ambient temperature sensor, an auxiliary circuit 9 is further connected to an input pipeline of the main circuit, the other end of the auxiliary circuit is connected to the other side chamber of the economizer 4 and then connected to the air-supply booster compressor 6, an auxiliary circuit electronic expansion valve 91 and an evaporation temperature sensor 92 are arranged on a pipeline of the main circuit connected to the economizer 4, and an exhaust temperature sensor 93 is arranged on a pipeline of the economizer 4 connected to the air-supply booster compressor 6.

As shown in fig. 1-3, the second pipeline 22 is further provided with a gas-liquid separator 221 on a pipeline connecting the port S of the four-way valve with the gas-supplementing booster compressor 6, a suction temperature sensor 222 and a low pressure sensor 223 on a pipeline connecting the port S of the four-way valve with the gas-liquid separator, and a discharge temperature sensor 225 and a high pressure sensor 226 on a pipeline connecting the port D of the four-way valve with the gas-supplementing booster compressor 6;

the electronic expansion valve of the main loop adopts suction superheat degree control, the suction superheat degree control is the existing PID control, the suction superheat degree is equal to suction temperature minus evaporation temperature, the suction temperature is collected through a compressor suction temperature sensor 222, and the evaporation temperature is saturation temperature corresponding to low-pressure detected by a low-pressure sensor 223.

The suction temperature sensor and the low-pressure sensor of the compressor 6 are arranged on a pipeline from the four-way valve to the gas-liquid separator instead of a pipeline from the gas-liquid separator to the return air port of the compressor 6, so that the problems that the control of the electronic expansion valve 217 of the main loop is unstable and the fluctuation of the opening degree and the superheat degree of the main valve is large due to the resistance loss in the gas-liquid separator can be avoided.

The working process is as follows:

1. a refrigeration mode:

the unit carries out refrigeration operation in summer and excessive season, and fin tubular heat exchanger 3 is as the condenser this moment, and water side heat exchanger 5 is as the evaporimeter: firstly, a high-temperature and high-pressure superheated gaseous refrigerant enters an air inlet D port of the four-way valve 1 through an air outlet of the compressor 6, and the four-way valve 1 is in a power-off state at the moment: an air inlet D port is communicated with an air outlet C port, an air return S port is communicated with an air outlet E port through a sliding bowl inside a four-way valve 1, high-temperature and high-pressure gaseous refrigerants enter a fin tube type heat exchanger 3 to perform forced convection heat exchange with air, the high-pressure supercooling liquid refrigerants coming out of the fin tube type heat exchanger 3 after heat exchange enter a refrigeration high-temperature liquid pipeline, namely a connecting pipeline I211, a needle valve III on the liquid pipeline is used for statically filling refrigerants on a unit, namely the refrigerants are filled when a compressor 6 is not started, the high-pressure medium-temperature liquid refrigerants pass through a check valve I from the tee joint I and enter an inlet pipeline of a liquid reservoir 7 through the tee joint III, a part of liquid refrigerants are introduced into a heat exchange tube at the bottom of the fin tube type heat exchanger to perform heat exchange with the air again through a tee joint V on the pipeline, the liquid refrigerants on the main pipeline directly enter the liquid reservoir 7, and the liquid refrigerants coming out of a heat exchange tube at the bottom of the fin tube type heat exchanger 3 are supercooled secondarily and are cooled with the liquid refrigerants in a main pipeline coming out of the liquid reservoir 7 In the media entering the filter, the refrigerant entering the user protection loop through three-way five-flow division in the system design and the refrigerant entering the liquid reservoir 7 on the main loop are in a parallel pipeline state, and how much refrigerant enters the heat exchange tube at the bottom of the fin tube type heat exchanger 3 is calculated and designed according to the principle that the resistance loss delta P of each branch pipeline in the parallel pipeline is consistent.

A part of liquid refrigerant coming out of the filter enters a condensation side of the economizer through the main loop, the other part of the liquid refrigerant enters an auxiliary loop pipeline, and when an electronic expansion valve 91 of the auxiliary loop meets the valve opening condition: ambient temperature T_aRefrigeration opening auxiliary valve ring temperature T not more than_aC-openCompressor 6 discharge temperature T_dThe exhaust temperature T of the auxiliary valve is not less than_d-openSaid ambient temperature T_aThe discharge temperature T of the compressor 6 is measured by an ambient temperature sensor_dThe open auxiliary valve discharge temperature T is measured by the compressor 6 discharge temperature sensor 224_d-openAnd refrigeration opening auxiliary valve ring temperature T_aC-openAll are set with temperature by control program, at this time, the auxiliary loop refrigerant passes through the auxiliaryThe loop electronic expansion valve 91 enters the evaporator side of the economizer after throttling, the heat is absorbed from the condenser of the economizer to form an overheated medium-pressure gaseous refrigerant, the overheated medium-pressure gaseous refrigerant enters the middle air supplement port of the compressor 6, the liquid refrigerant in the condensation side of the economizer 4 is subjected to heat release cooling, the liquid refrigerant is subcooled again and then enters the main loop electronic expansion valve 217 from the condensation side of the economizer 4 for throttling, and the needle valve IV is a vacuum needle valve for vacuumizing the unit. The main circuit electronic expansion valve 217 is controlled by suction superheat, which is the suction temperature T, through a suction temperature sensor 222 and a low pressure sensor 223 of the compressor 6_i-evaporation temperature T_eWherein the suction temperature T_iMeasured by the compressor 6 suction temperature sensor 222, T_eLow pressure P detected for the low pressure sensor 223_LThe corresponding saturation temperature.

The low-pressure gas-liquid mixed refrigerant throttled by the electronic expansion valve 227 of the main loop is communicated with a check valve II close to the water side heat exchanger through a tee joint valve IV (the throttled refrigerant cannot pass through the check valve II close to the connecting pipeline I, because the outlet of the check valve II close to the connecting pipeline I is a high-pressure liquid refrigerant side, the low-pressure saturated refrigerant cannot be allowed to pass through under the action of pressure difference), the low-pressure gas-liquid mixed refrigerant enters the water side heat exchanger 5 through the tee joint valve II and carries out heat convection with chilled water in the other chamber of the water side heat exchanger to form low-pressure superheated gaseous refrigerant, the low-pressure superheated gaseous refrigerant coming out of the water side heat exchanger 5 enters an E port of a four-way valve 1, the low-pressure superheated gaseous refrigerant passes through the S port of the four-way valve 1 and enters a gas-liquid classifier, and when the system is designed, a suction temperature sensor 222 and a low-pressure sensor 223 of the compressor 6 are placed on a pipeline from the four-way valve 1 to a gas-liquid separator 221 and a non-liquid separator to the return port of the compressor 6 In this way, unstable control of the main circuit electronic expansion valve 217 due to the resistance loss in the gas-liquid separator 221 and large fluctuation in the main valve opening and superheat can be avoided. The low-pressure superheated gaseous refrigerant enters the gas return pipeline of the compressor 6 after passing through the gas-liquid separator and returns to the suction cavity of the compressor 6 to complete a refrigeration cycle.

2. Heating mode:

the unit heats the operation in winter, and fin tubular heat exchanger 3 is as the evaporimeter this moment, and water side heat exchanger 5 is as the condenser: firstly, a high-temperature and high-pressure superheated gaseous refrigerant enters an air inlet D port of the four-way valve 1 through an air outlet of the compressor 6, and the four-way valve is in an electrified state at the moment: an air inlet D port is communicated with an air outlet E port, a sliding bowl in the four-way valve is used for communicating an air return S port with an air outlet C port, high-temperature and high-pressure gaseous refrigerants pass through the four-way valve 1 and then enter a water side heat exchanger 5 to perform forced convection heat exchange with air-conditioning hot water, high-pressure supercooled liquid refrigerants coming out of the water side heat exchanger 5 are converged at a tee joint, high-pressure medium-temperature liquid refrigerants starting from the tee joint enter a reservoir inlet pipeline through a one-way valve I of a connecting pipeline II and a tee joint III, a part of liquid refrigerants are led into a heat exchange tube at the bottom of a fin tube type heat exchanger to perform heat exchange with air again through the tee joint V on the pipeline, the liquid refrigerants on a main pipeline directly enter a reservoir 7, the high-pressure liquid refrigerants coming out of the heat exchange tube at the bottom of the fin tube type heat exchanger are supercooled for the second time and are converged with the high-pressure liquid refrigerants in a main pipeline coming out of the reservoir 7 through the tee joint VI and then enter a filter, the refrigerant entering the bottom overheating pipeline of the finned shell-and-tube heat exchanger through three-way five-flow in the system design and the refrigerant entering the liquid reservoir 7 on the main loop are in a parallel pipeline state, the amount of the refrigerant entering the bottom overheating pipeline of the finned tube heat exchanger is calculated according to the principle that the resistance value delta P of each branch pipeline in the parallel pipeline is consistent, the resistance of each branch pipeline and the resistance of the liquid reservoir in different ring temperature heating modes are reasonably calculated, so that the amount of the refrigerant entering the bottom overheating pipeline of the finned tube heat exchanger in different ring temperature heating modes and the heat release amount of the part of the refrigerant are calculated, the heat release amount of the part of the refrigerant is used for ensuring that the bottom of the finned tube heat exchanger cannot be frozen in the snowy weather or even in the snowy weather, and the lower environment temperature and the more heat production attenuation of the unit are realized under the condition that the temperature of the unit is unchanged, the more liquid refrigerants are stored in the liquid reservoir, and then the larger the resistance of the refrigerant in the liquid reservoir is, so more liquid refrigerant is shunted out from the tee joint five to enter the bottom of the finned tube heat exchanger for preheating and supercooling, and for the finned tube heat exchanger, the lower the ambient temperature is, more heat is needed to maintain the bottom temperature to ensure that the bottom of the finned tube heat exchanger cannot be frozen in heavy snow days or even snowstorm days.

Part of high-pressure liquid refrigerant coming out of the filter enters a condensation side in the economizer 4 through the main loop, the other path enters an auxiliary loop pipeline, and when an auxiliary loop electronic expansion valve meets a valve opening condition: ambient temperature T_aHeating opening auxiliary valve ring temperature T is less than or equal to_aH-openCompressor discharge temperature T_dThe exhaust temperature T of the auxiliary valve is not less than_d-openAt this time, the auxiliary loop refrigerant enters the evaporation side of the economizer 4 after being throttled by the auxiliary loop electronic expansion valve 91, absorbs heat from the condensation side of the economizer 4 to form an overheated medium-pressure gaseous refrigerant and then enters the middle air supplement port of the compressor 6, the liquid refrigerant in the condensation side of the economizer 4 is subjected to heat release cooling, the refrigerant is supercooled again and then enters the main loop electronic expansion valve 217 from the condensation side of the economizer 4 to be throttled, the main loop electronic expansion valve adopts suction superheat degree control and is realized through a compressor suction temperature sensor 222 and a low-pressure sensor 223 (suction superheat degree is equal to suction temperature T_i-evaporation temperature T_eWherein T is_eLow pressure P detected for low pressure sensor LPS_LCorresponding saturation temperature).

The low-pressure gas-liquid mixed refrigerant throttled by the electronic expansion valve 217 of the main loop passes through a tee joint four and a check valve two close to a connecting pipeline one (the throttled refrigerant cannot pass through the check valve two close to the connecting pipeline two because the outlet of the check valve two close to the connecting pipeline two is a high-pressure liquid refrigerant side and the low-pressure saturated refrigerant cannot pass through under the action of pressure difference) and the tee joint one enter the fin tube type heat exchanger 3 to perform convective heat exchange with air to form a low-pressure superheated gaseous refrigerant, the low-pressure superheated gaseous refrigerant coming out of the fin tube type heat exchanger 3 enters a C port of the four-way valve 1, and the C port is communicated with the S port at the moment, so the low-pressure superheated gaseous refrigerant enters a gas-liquid classifier after passing through the S port of the four-way valve 1, and when the system is designed, a compressor suction temperature sensor 222 and a low-pressure sensor 223 are arranged on a pipeline from the four-way valve 1 to a gas-liquid separator but not on a pipeline from the gas-liquid separator to a compressor return gas port, this can avoid unstable control of the main circuit electronic expansion valve 217 due to resistance loss in the gas-liquid separator and large fluctuation of the main valve opening and superheat. The low-pressure superheated gaseous refrigerant enters the gas return pipeline of the compressor 6 and returns to the suction cavity of the compressor 6 after passing through the gas-liquid separator to complete a heating cycle.

In the heating mode, the finned tube heat exchanger 3 is used as an evaporator, the temperature of a gas-liquid mixed refrigerant flowing through an internal heat exchange tube of the finned tube heat exchanger is lower than the air inlet temperature of the fins, the refrigerant absorbs heat into air, when the air flows in snowy days or even snowy days, a large amount of snow can be absorbed on the surfaces of the fins under the suction action of an axial flow fan, when a unit meets defrosting conditions, defrosted water formed after a frost layer attached to the surfaces of the fins is melted can flow to the bottom of the finned tube heat exchanger along gaps of the fins, the defrosted water is easily mixed with snow on the outermost layers of the surfaces of the fins to form ice layers when the defrosted water flows downwards to the bottom, the ice layers are accumulated to a certain degree and completely block a drainage channel, and the icing condition of the surfaces of the fins is worsened, but the middle bottom of the finned tube heat exchanger is preheated by adopting high-temperature liquid refrigerant, so that a plurality of loops at the bottom of the finned tube heat exchanger are always at a temperature of more than 5 ℃, and the condition that the freezing at the bottom of the finned tube heat exchanger is completely eradicated Meanwhile, the part of the refrigerant which is preheated is supercooled for the second time before entering the economizer, the supercooling degree of a high-pressure liquid refrigerant before entering the economizer is increased, the supercooling of the economizer is realized after the refrigerant passes through the condensation side of the economizer again, so that the supercooling degree of the high-pressure liquid refrigerant is increased, the refrigerant in and out enthalpy difference in the evaporator (the refrigerant in and out of the finned tube heat exchanger 3 is further increased, the heat exchange quantity in the evaporator is improved, and meanwhile, the medium-pressure superheated gaseous refrigerant which is discharged from the evaporation side of the economizer 4 enters the air supplementing port of the compressor 6, so that the heating circulation refrigerant quantity of the compressor 6 is improved, and the integral heating quantity of the unit is improved by integrating the two aspects.

The design of ultra-low temperature forced air cooling module unit system that involves in this patent still includes following two kinds of modes:

as shown in fig. 4, the input end of the auxiliary loop is communicated with the output pipeline to carry out the downstream liquid taking mode of the economizer;

as shown in fig. 5, the input end of the auxiliary loop is communicated with the bottom of the liquid reservoir to take liquid from the bottom of the liquid reservoir.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.