CN203454452U - Intermediate adequacy cooling double operating conditions refrigeration system in secondary throttling - Google Patents

Abstract

The utility model discloses a dual-working condition refrigeration system with secondary throttling and intermediate complete cooling, which provides a double-stage compression that can realize variable flow rate single-stage vapor compression cycle and variable flow rate secondary throttling intermediate complete cooling. cycle system. Including multiple sets of variable flow compression condensing units connected in parallel between the high temperature suction pipeline, low temperature suction pipeline and medium pressure liquid supply pipeline; each set of variable flow compression condensing units consists of a low pressure constant flow compressor, a low pressure variable flow , high pressure variable flow compressor, first one-way valve, second one-way valve, third one-way valve, first valve, second valve, third valve, fourth valve, fifth valve, condenser, intercooler device and throttle valve. Through the opening or closing of multiple valves, the air can be sucked from the high-temperature suction line to realize the single-stage compression refrigeration cycle to supply liquid to the medium-pressure liquid supply line, and the air can be sucked from the low-temperature suction line to achieve secondary throttling The intermediate complete cooling two-stage compression refrigeration cycle supplies liquid to the medium pressure liquid supply line.

Description

Secondary throttling intermediate complete cooling dual working condition refrigeration system

technical field

The utility model relates to the technical field of refrigeration, in particular to a two-stage compression refrigeration system with secondary throttling, intermediate complete cooling, dual working conditions, and refrigerating capacity adjustment by changing the refrigerant flow rate.

Background technique

The existing two-stage compression refrigeration system used for freezing cold storage usually uses temperature control to start and stop the compressor. When the temperature of the cold storage reaches the temperature set by the thermostat, the refrigeration system stops working; when the temperature rises to the upper limit set by the thermostat, The cooling system is on. There is a contradiction in such a system. When the temperature difference between startup and shutdown is relatively large, the food stored in the frozen storage will lose water and dryness due to different freezing rates, and food quality will decline; when the temperature difference between startup and shutdown is relatively small, refrigeration The frequent opening of the system will not only increase the power consumption, but also reduce the service life of the refrigeration system. In addition, the existing two-stage compression refrigeration system has a fixed high-pressure and low-pressure volume ratio of 1:3 or 1:2. For refrigeration systems with changing condensing temperatures, since the high-pressure and low-pressure volume ratios cannot be adjusted, the refrigeration system is not in the best condition. Work.

The multi-connected air conditioning system composed of multiple compression condensing units and multiple indoor evaporators realizes the control of cooling capacity by changing the refrigerant flow rate. The system is flexible in operation and easy to control, and is widely used in the field of air conditioning. However, the existing multi-connected air-conditioning systems are all single-stage compression refrigeration systems, which are only applicable to the field of air-conditioning, and are not suitable for freezing cold storage systems with low temperatures.

For the parallel system of frozen cold storage (lower suction temperature, usually requires a two-stage compression system) and cold storage (higher suction temperature, usually requires a single-stage vapor compression system), it is often necessary to use single and double-stage vapor compression systems. Separately configured, the one-time investment of the system is large, and the adjustment of the cooling capacity is completely realized by starting and stopping.

Utility model content

The purpose of this utility model is to provide a parallel connection of multiple sets of variable flow compression condensing units in view of the technical defect that the cooling capacity adjustment in the prior art is completely realized by starting and shutting down, which can realize the variable flow single-stage vapor compression cycle, It can also realize a two-stage compression cycle refrigeration system with variable flow rate, secondary throttling, and complete cooling in the middle.

The technical scheme adopted for realizing the purpose of this utility model is:

A two-stage throttling intermediate complete cooling double-working condition refrigeration system, characterized in that it includes multiple sets of variable flow compression condensing units connected in parallel between the high-temperature suction pipeline, the low-temperature suction pipeline and the medium-pressure liquid supply pipeline The variable flow compression condensing unit of each group is composed of a low-pressure constant-flow compressor, a low-pressure variable-flow compressor, a high-pressure variable-flow compressor, a first check valve, a second check valve, a third check valve, and a first valve , the second valve, the third valve, the fourth valve, the fifth valve, a condenser, an intercooler and a throttling valve; the first valve inlet and the high temperature The suction pipeline is connected, the inlet of the second valve is connected with the low-temperature suction pipeline, the liquid outlet of the intercooler is connected with the medium-pressure liquid supply pipeline; the outlet of the first valve and the The outlet of the second valve is respectively connected to the suction port of the low-pressure constant-flow compressor, the suction port of the low-pressure variable-flow compressor and the inlet of the fourth valve, and the exhaust port of the low-pressure constant-flow compressor is connected to the first A one-way valve inlet is connected, the exhaust port of the low-pressure variable flow compressor is connected to the second one-way valve inlet, and the first one-way valve outlet is connected in parallel with the second one-way valve outlet respectively to the The inlet of the fifth valve is connected to the inlet below the liquid surface of the intercooler, the gas outlet of the intercooler is connected to the inlet of the third valve, and the outlet of the third valve is connected in parallel with the outlet of the fourth valve to the high pressure The suction port of the variable flow compressor is connected, the exhaust port of the high-pressure variable flow compressor is connected with the inlet of the third check valve, and the outlet of the third check valve is connected in parallel with the outlet of the fifth valve and then connected with the outlet of the fifth valve. The condenser inlet is connected, and the condenser outlet is connected to the intercooler inlet through the throttle valve; by controlling the opening of the first valve, the second valve, the third valve, the fourth valve and the fifth valve Or closed, it can not only suck air from the high-temperature suction line to realize single-stage compression refrigeration cycle to supply liquid to the medium-pressure liquid supply line, but also can suck air from the low-temperature suction line to realize secondary throttling The intermediate complete cooling two-stage compression refrigeration cycle supplies liquid to the medium-pressure liquid supply pipeline.

The low-pressure constant-flow compressor is any one of a scroll compressor, a rotary compressor, a screw compressor, and a piston compressor.

The low-pressure variable-flow compressor and the high-pressure variable-flow compressor are any one of a scroll compressor, a rotary compressor, a screw compressor, and a piston compressor. By adjusting the variable voltage of the DC motor, the flow regulation of the refrigerant can also be realized by unloading and loading the refrigerant.

The condenser is an air-cooled condenser, a water-cooled condenser, an evaporative condenser or other types of condensers.

The throttle valve is an electronic expansion valve, a thermal expansion valve, a capillary or an orifice.

The intercooler is a plate heat exchanger or a casing heat exchanger.

Compared with the prior art, the beneficial effects of the utility model are:

1. Energy saving: the refrigeration system of the present utility model is composed of variable flow compression condensing units connected in parallel. Refrigerant flow in cold storage and cold storage can be adjusted according to load requirements, which overcomes the technical defect that the adjustment of cooling capacity is completely realized by starting and stopping, and the refrigeration system will not be opened frequently.

2. The temperature of the cold storage is constant: since the refrigerant flow of the refrigeration system can be adjusted, the system can automatically adjust the refrigerant flow according to the load change of the frozen storage. After reaching the set temperature, the refrigeration system will work at a lower refrigerant flow to maintain the frozen The temperature of the cold storage and cold storage avoids the fluctuation of the internal temperature of the cold storage, and effectively reduces the dehydration and dry consumption of food caused by temperature fluctuations.

3. Less one-time investment: The variable flow compression condensing unit in the refrigeration system of the present utility model can not only suck air from the high-temperature suction pipeline to realize single-stage compression refrigeration cycle to supply liquid to the medium-pressure liquid supply pipeline, but also can Air suction from the low-temperature suction pipeline realizes secondary throttling, complete cooling in the middle, and a two-stage compression refrigeration cycle to supply liquid to the medium-pressure liquid supply pipeline. Parallel variable flow compression condensing units do not interfere with each other in work, and can realize variable flow operation, one machine with multiple functions, reducing the one-time investment.

4. The unit can achieve the best working condition: the refrigeration system of the utility model is composed of variable flow compression condensing units connected in parallel, and each group of variable flow compression condensing units includes a low-pressure constant-flow compressor, a low-pressure variable-flow compressor and a high-pressure variable-flow compressor. The compressor overcomes the shortcomings of fixed high and low pressure volume ratios in the prior art, and realizes the adjustable volume ratio. No matter how the working conditions change, the refrigeration system is always working in the best state, with low energy consumption.

5. Modularization: High-pressure variable-flow compressors and low-pressure variable-flow compressors can use compressors with the same rated input power, which is conducive to system adjustment and easy repair and maintenance, and it is easier to realize system modularization.

Description of drawings

Fig. 1 is a schematic diagram of a dual-working-condition refrigeration system with secondary throttling and complete cooling in the middle of the utility model.

In the figure: 1. High temperature suction pipeline, 2. Low temperature suction pipeline, 3. Medium pressure liquid supply pipeline, 4. Low pressure constant flow compressor, 5. Low pressure variable flow compressor, 6. High pressure variable flow compression Machine, 7-1. the first one-way valve, 7-2. the second one-way valve, 7-3. the third one-way valve, 8-1. the first valve, 8-2. the second valve, 8- 3. Third valve, 8-4. Fourth valve, 8-5. Fifth valve, 9. Condenser, 10. Intercooler, 11. Throttle valve.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail.

Figure 1 is a schematic diagram of the dual-working condition refrigeration system with secondary throttling and complete cooling in the middle of the utility model, including the high-temperature suction pipeline 1, the low-temperature suction pipeline 2 and the medium-pressure liquid supply pipeline 3 connected in parallel Multiple sets of variable flow compression condensing units between. Each group of variable flow compression condensing units includes a low-pressure constant-flow compressor 4, a low-pressure variable-flow compressor 5, a high-pressure variable-flow compressor 6, a first check valve 7-1, a second check valve 7-2, and a second check valve 7-2. Three check valves 7-3, first valve 8-1, second valve 8-2, third valve 8-3, fourth valve 8-4, fifth valve 8-5, condenser 9, intercooler 10 and throttle valve 11. The inlet of the first valve 8-1 in each group of variable flow compression condensing units is connected to the high-temperature suction pipeline 1, and the inlet of the second valve 8-2 is connected to the low-temperature suction pipeline 2 , the liquid outlet of the intercooler 10 is connected to the medium-pressure liquid supply pipeline 3, the outlet of the first valve 8-1 and the outlet of the second valve 8-2 are respectively connected to the low-pressure constant-flow compressor 4 The suction port, the suction port of the low-pressure variable-flow compressor 5 is connected to the inlet of the fourth valve 8-4, and the exhaust port of the low-pressure constant-flow compressor 4 is connected to the inlet of the first one-way valve 7-1 connection, the exhaust port of the low-pressure variable flow compressor 5 is connected to the inlet of the second one-way valve 7-2, and the outlet of the first one-way valve 7-1 is connected to the outlet of the second one-way valve 7-2 After parallel connection, it is respectively connected to the inlet of the fifth valve 8-5 and the inlet below the liquid level of the intercooler 10, the gas outlet of the intercooler 10 is connected to the inlet of the third valve 8-3, and the third valve 8 -3 the outlet is connected in parallel with the outlet of the fourth valve 8-4 and then connected to the suction port of the high-pressure variable flow compressor 6, and the exhaust port of the high-pressure variable flow compressor 6 is connected to the third one-way valve 7- 3 inlet connection, the outlet of the third one-way valve 7-3 is connected in parallel with the outlet of the fifth valve 8-5 and then connected to the inlet of the condenser 9, and the outlet of the condenser 9 is connected to the outlet of the condenser 9 through the throttle valve 11 The inlet of the intercooler 10 is connected.

The variable flow compression condensing unit in the two-stage throttling intermediate complete cooling dual-working condition refrigeration system of this embodiment can suck air from the high-temperature suction pipeline 1 to realize a single-stage compression refrigeration cycle to the medium-pressure liquid supply pipeline 3 For liquid supply, air can be sucked from the low-temperature suction pipeline 2 to realize secondary throttling, complete cooling in the middle, and a two-stage compression refrigeration cycle to supply liquid to the medium-pressure liquid supply pipeline 3 . Parallel variable flow compression condensing units do not interfere with each other during work, and all can realize variable flow operation.

1. Inhale air from the high-temperature suction line 1 to realize a single-stage compression refrigeration cycle and supply liquid to the medium-pressure liquid supply line 3:

The second valve 8-2 and the third valve 8-3 in the variable flow compression condensing unit are closed, and the first valve 8-1, the fourth valve 8-4 and the fifth valve 8-5 are opened. The low-pressure refrigerant vapor returning from the cold storage to the variable-flow compression condensing unit enters the low-pressure constant-flow compressor 4, the low-pressure variable-flow compressor 5, and the high-pressure variable-flow compressor 6 through the high-temperature suction pipeline 1 for compression. The high-pressure refrigerant vapor is condensed into a high-pressure liquid in the condenser 9 through the first one-way valve 7-1, the second one-way valve 7-2 and the third one-way valve 7-3 respectively, and is throttled once at the throttle valve 11. The medium-pressure saturated gas-liquid two-phase refrigerant flows through the intercooler 10 and enters the medium-pressure liquid supply pipeline 3 to supply liquid to the refrigerator.

2. Inhale air from the low-temperature suction line 2 to realize a two-stage compression refrigeration cycle and supply liquid to the medium-pressure liquid supply line 3:

The first valve 8-1, the fourth valve 8-4 and the fifth valve 8-5 in the variable flow compression condensing unit are closed, and the second valve 8-2 and the third valve 8-3 are opened. The low-pressure refrigerant vapor returning from the freezer to the variable-flow compression condensing unit enters the low-pressure constant-flow compressor 4 and the low-pressure variable-flow compressor 5 through the low-temperature suction line 2 for one-stage compression, and the compressed medium-pressure superheats Vapor refrigerant enters the liquid in the intercooler 10 from below the liquid surface of the intercooler 10 through the first one-way valve 7-1 and the second one-way valve 7-2 respectively, and is cooled by the liquid to a saturated state. The medium-pressure saturated vapor refrigerant from the gas outlet of the condenser 10 enters the high-pressure variable flow compressor 6 for second-stage compression, and the compressed high-pressure superheated vapor refrigerant is condensed into a high-pressure liquid refrigerant by the condenser 9, and is discharged at the throttle valve 11 The mid-throttle is the mid-pressure saturated gas-liquid two-phase refrigerant that enters the intercooler 10, the mid-pressure saturated vapor refrigerant participates in the second-stage compression, and the mid-pressure saturated liquid refrigerant passes through the mid-pressure liquid supply pipeline in three directions. Refrigerated supply liquid.

In the single-stage compression refrigeration cycle of the above system, the combination of the low-pressure constant-flow compressor 4, the low-pressure variable-flow compressor 5, and the high-pressure variable-flow compressor 6 satisfies the control of the refrigerant flow rate in the single-stage compression refrigeration cycle under different load conditions. .

In the two-stage compression refrigeration cycle of the above system, when the load of the freezer is small, the low-pressure variable-flow compressor 5 and the high-pressure variable-flow compressor 6 work at the same time, by adjusting the high-pressure variable-flow compressor 6 and the low-pressure variable-flow compressor 5 Refrigerant flow achieves the best volume ratio of high and low pressure in the system; when the load of the frozen storage is large, the low-pressure constant-flow compressor 4, low-pressure variable-flow compressor 5, and high-pressure variable-flow compressor 6 work simultaneously, and by adjusting the low-pressure variable-flow The refrigerant flow of the compressor 5 and the high-pressure variable-flow compressor 6 realizes the best high-low pressure volume ratio of the system. The system can adjust the refrigerant flow in the two-stage compression refrigeration cycle according to the load change of the freezer.

The function of the first one-way valve 6-1, the second one-way valve 6-2 and the third one-way valve 6-3 in the above embodiment is to prevent backflow when the compressor is not working.

The low-pressure constant-flow compressor described in the utility model is any one of a scroll compressor, a rotor compressor, a screw compressor, a piston compressor, or other types of compressors. The low-pressure variable-flow compressor and the high-pressure variable-flow compressor are any one of a scroll compressor, a rotary compressor, a screw compressor, a piston compressor, or other types of compressors, and the variable flow method can be through By adjusting the frequency conversion of the AC motor or the variable voltage of the DC motor, the flow regulation of the refrigerant can also be realized by unloading and loading the refrigerant. The condenser is an air-cooled condenser, a water-cooled condenser, an evaporative condenser or other types of condensers. The throttling valve is any one of electronic expansion valve, thermal expansion valve, capillary or orifice throttling, or other throttling devices capable of reducing pressure. The intercooler may be a plate heat exchanger, a casing heat exchanger or other types of heat exchangers.

The valve described in the utility model can be a manual valve or an electric valve, and can also be replaced by a three-way valve or a four-way valve.

When the secondary throttling intermediate complete cooling dual-working condition refrigeration system of the utility model is used in practice, the high-pressure compressor and the low-pressure compressor can use the compressor with the same rated input power, which is beneficial to system adjustment and is convenient for repair and maintenance. It is easier to realize the modularization of the system.

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made, these Improvement and retouching should also be regarded as the protection scope of the present utility model.

Claims (6)

1. a complete cooling Double-working-condition refrigeration system in the middle of second throttle, is characterized in that, comprises the many groups variable-flow compression freezing machine group being connected in parallel between high temperature suction line, low temperature suction line and middle pressure liquid feeding pipeline, described in every group, variable-flow compression freezing machine group is comprised of low pressure constant flow compressor, low pressure variable-flow compression machine, high voltage variable flow compressor, the first check valve, the second check valve, the 3rd check valve, the first valve, the second valve, the 3rd valve, the 4th valve, the 5th valve, condenser, intercooler and choke valve, described the first valve inlet described in every group in variable-flow compression freezing machine group is connected with described high temperature suction line, and described the second valve inlet is connected with described low temperature suction line, and the liquid outlet of described intercooler is connected with described middle pressure liquid feeding pipeline, described the first valve export and described the second valve export respectively with described low pressure constant flow compressor air suction mouth, described low pressure variable-flow compression machine air entry is connected with described the 4th valve inlet, described low pressure constant flow exhaust outlet of compressor is connected with described the first check valve inlet, described low pressure variable-flow compression machine exhaust outlet is connected with described the second check valve inlet, below import is connected with intercooler liquid level with described the 5th valve inlet respectively with after described the second check valve outlet parallel connection in described the first check valve outlet, described intercooler gas vent is connected with described the 3rd valve inlet, described the 3rd valve export with after described the 4th valve export parallel connection, be connected with described high voltage variable flow compressor air entry, described high voltage variable flow compressor exhaust outlet is connected with described the 3rd check valve inlet, described the 3rd check valve outlet is connected with described condenser inlet with after described the 5th valve export parallel connection, described condensator outlet is connected with described intercooler import through described choke valve, by controlling the unlatching of described the first valve, the second valve, the 3rd valve, the 4th valve and the 5th valve or closing, both can be from the air-breathing single stage compress kind of refrigeration cycle that realizes of described high temperature suction line to pressure liquid feeding pipeline feed flow described, can realize in the middle of second throttle complete cooling Two-stage Compression kind of refrigeration cycle to pressure liquid feeding pipeline feed flow described from described low temperature suction line is air-breathing again.

2. complete cooling Double-working-condition refrigeration system in the middle of second throttle according to claim 1, is characterized in that, described low pressure constant flow compressor is any in screw compressor, rotor compressor, helical-lobe compressor, piston compressor.

3. complete cooling Double-working-condition refrigeration system in the middle of second throttle according to claim 1, it is characterized in that, described low pressure variable-flow compression machine and described high voltage variable flow compressor are any in screw compressor, rotor compressor, helical-lobe compressor, piston compressor, variable-flow mode is by regulating to the frequency conversion of alternating current generator or by the time variant voltage to direct current generator, or adopts cold-producing medium unloading and load mode to realize the Flow-rate adjustment of cold-producing medium.

4. complete cooling Double-working-condition refrigeration system in the middle of second throttle according to claim 1, is characterized in that, described condenser is air-cooled condenser, water-cooled condenser or evaporative condenser.

5. complete cooling Double-working-condition refrigeration system in the middle of second throttle according to claim 1, is characterized in that, described choke valve is electric expansion valve, heating power expansion valve, capillary or orifice plate.

6. complete cooling Double-working-condition refrigeration system in the middle of second throttle according to claim 1, is characterized in that, described intercooler is plate type heat exchanger or double pipe heat exchanger.