Not exclusively variable-flow double-stage compressive refrigerating system is cooled in the middle of second throttle
Technical field
The present invention relates to refrigeration technology field, particularly relate in the middle of a kind of second throttle carrying out refrigerating capacity adjustment by changing refrigerant flow and not exclusively cool variable-flow double-stage compressive refrigerating system.
Background technology
The existing double-stage compressive refrigerating system for cold storage freezer adopts temperature to control the start-stop of compressor usually, and when temperature of ice house reaches temperature controller set temperature, refrigeration system quits work; Prescribe a time limit when temperature rises on temperature controller set temperature, refrigeration system is opened.There is a contradiction in such system, when needs startup-shutdown Temperature Difference Ratio is larger, can cause the food dehydration drying loss that in cold storage freezer, store food is brought due to freezing rate difference, food quality declines; When needs startup-shutdown Temperature Difference Ratio is less, refrigeration system is opened frequently, and not only power consumption increases, and can reduce the service life of refrigeration system.In addition existing double-stage compressive refrigerating system high and low pressure volumetric ratio is fixing 1:3 or 1:2, and for the refrigeration system that condensation temperature constantly changes, because high and low pressure volumetric ratio is non-adjustable, refrigeration system is not work under optimum, and energy consumption is high.
At present, the system mainly multi-connected air conditioning system of controlling capacity of refrigeration is realized by changing refrigerant flow, multi-connected air conditioning system is made up of multiple stage Condensing units and multiple stage indoor evaporator, system realizes the control of refrigerating capacity by changing refrigerant flow, system cloud gray model is flexible, be easy to control, be widely used in field of air conditioning.But existing multi-gang air conditioner is all single-stage compression refrigeration system, and cryogenic temperature is higher, is only applicable to field of air conditioning, be not suitable for the cold storage refrigeration storage system that temperature is lower.
Summary of the invention
The object of the invention is the technological deficiency for existing in prior art, and provide a kind of multiple stage Condensing units in parallel, carrying out the second throttle middle not exclusively cooling variable-flow double-stage compressive refrigerating system of refrigerating capacity adjustment by changing refrigerant flow.
The technical scheme adopted for realizing object of the present invention is:
Not exclusively cool variable-flow double-stage compressive refrigerating system in the middle of a kind of second throttle, comprise the many groups variable-flow Two-stage Compression condensation unit be connected in parallel between low pressure air suction pipeline and middle pressure liquid feeding pipeline; Often organize described variable-flow Two-stage Compression condensation unit to be made up of low pressure constant flow compressor, low pressure variable-flow compressor, high voltage variable flow compressor, the first check valve, the second check valve, condenser, choke valve and intercooler; The described low pressure constant flow compressor often organized in described variable-flow Two-stage Compression condensation unit is connected with described low pressure air suction pipeline with described low pressure variable-flow compressor air entry is in parallel simultaneously, and the described intercooler liquid outlet often organized in described variable-flow Two-stage Compression condensation unit is connected with described middle pressure liquid feeding pipeline; Described low pressure constant flow exhaust outlet of compressor is connected with described first check valve inlet, described low pressure variable-flow exhaust outlet of compressor is connected with described second check valve inlet, described first one-way valved outlet, described second one-way valved outlet are connected with described high voltage variable flow compressor air entry with after the parallel connection of described intercooler gas vent, described high voltage variable flow compressor exhaust outlet is connected with described condenser inlet, and described condensator outlet is connected with described intercooler import by described choke valve; When cold storage freezer load is less, described low pressure variable-flow compressor and high voltage variable flow compressor work simultaneously; When cold storage freezer load is larger, described low pressure constant flow compressor, low pressure variable-flow compressor and high voltage variable flow compressor work simultaneously; When needing low refrigerant flow, low pressure variable-flow compressor and high voltage variable flow compressor work simultaneously, low pressure constant flow compressor shutdown; When needing intermediate refrigerant flow, low pressure constant flow compressor and high voltage variable flow compressor work simultaneously, low pressure variable-flow compressor shutdown; When needing high refrigerant flow, low pressure constant flow compressor, high voltage variable flow compressor and low pressure variable-flow compressor work simultaneously.
Described low pressure variable-flow compressor and high voltage variable flow compressor are any one in screw compressor, rotor compressor, helical-lobe compressor, piston compressor, adopt AC frequency conversion, DC frequency-changing or unloading-load time control mode to carry out the adjustment of variable refrigerant volume.
Described choke valve is electric expansion valve, heating power expansion valve, capillary or orifice plate.
Described intercooler is plate type heat exchanger or double pipe heat exchanger.
Described low pressure constant flow compressor is any one in screw compressor, rotor compressor, helical-lobe compressor, piston compressor.
Compared with prior art, the invention has the beneficial effects as follows:
1, energy-conservation: in double-stage compressive refrigerating system of the present invention, low-pressure stage compressor is become with low pressure variable-flow compressor bank by low pressure constant flow compressor, can starting or stoping according to required refrigerant flow control associated compressors, refrigerating capacity adjustment is carried out by changing refrigerant flow, thus meeting the requirement of various load to refrigerating capacity, refrigeration system can not frequently be opened.Simultaneously by changing the refrigerant flow that high and low pressure compressor exports, overcome in prior art the shortcoming of fixing high and low pressure volumetric ratio, no matter how operating mode changes, and refrigeration system is always in optimum state work, reaches energy-conservation object.Owing to adopting two-shipper compression, cryogenic temperature is low, is applicable to the cold storage refrigeration storage system that temperature is lower.
2, cold storage temperature of ice house is constant: owing to can adjust the refrigerant flow of refrigeration system, system can adjust refrigerant flow automatically according to the load variations of cold storage freezer, after reaching design temperature, refrigeration system can with lower refrigerant flow work, maintain cold storage temperature of ice house, avoid the fluctuation of cold storage cool house internal temperature, effectively reduce the dehydration drying loss of the freezed food brought due to temperature fluctuation.
3, low cost of manufacture: a fixed frequency air conditioner compressor and two frequency converting air-conditioner compressor combos composition variable-flow Two-stage Compression condensation units can be adopted, manufacturing cost than existing single-head Two-stage Compression condensation unit or the Two-stage Compression condensation unit that is made up of cryogenic compressor combo low.
4, modularization: high pressure compressor and low pressure compressor can adopt the compressor of same rated input power, are conducive to the adjustment of system and are convenient to maintenance process simulation, more easily realizes the modularization of system simultaneously.
Accompanying drawing explanation
Figure 1 shows that and not exclusively cool variable-flow double-stage compressive refrigerating system schematic diagram in the middle of second throttle of the present invention.
In figure: 1. low pressure air suction pipeline, press liquid feeding pipeline 2., 3. low pressure constant flow compressor, 4. low pressure variable-flow compressor, 5. high voltage variable flow compressor, 6-1. first check valve, 6-2. second check valve, 7. condenser, 8. choke valve, 9. intercooler.
Detailed description of the invention
Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.
Figure 1 shows that and not exclusively cool variable-flow double-stage compressive refrigerating system schematic diagram in the middle of second throttle of the present invention, comprise the many groups variable-flow Two-stage Compression condensation unit be connected in parallel between low pressure air suction pipeline 1 and middle pressure liquid feeding pipeline 2.Often organize described variable-flow Two-stage Compression condensation unit to be made up of low pressure constant flow compressor 3, low pressure variable-flow compressor 4, high voltage variable flow compressor 5, first check valve 6-1, the second check valve 6-2, condenser 7, choke valve 8 and intercooler 9.The described low pressure constant flow compressor 3 often organized in described variable-flow Two-stage Compression condensation unit is connected with described low pressure air suction pipeline 1 with described low pressure variable-flow compressor 4 air entry is in parallel simultaneously, and described intercooler 9 liquid outlet often organized in described variable-flow Two-stage Compression condensation unit is connected with described middle pressure liquid feeding pipeline 2.Described low pressure constant flow compressor 3 exhaust outlet is connected with described first check valve 6-1 import, described low pressure variable-flow compressor 4 exhaust outlet is connected with described second check valve 6-2 import, described first check valve 6-1 exports, described second check valve 6-2 outlet is connected with described high voltage variable flow compressor 5 air entry with after the parallel connection of described intercooler 9 gas vent, described high voltage variable flow compressor 5 exhaust outlet is connected with the import of described condenser 7, and described condenser 7 is exported and is connected with described intercooler import by described choke valve 8.
The low-pressure steam cold-producing medium getting back to not exclusively cooling variable-flow double-stage compressive refrigerating system in the middle of second throttle by cold storage freezer enters into low pressure constant flow compressor 3 through low pressure air suction pipeline 1 and low pressure variable-flow compressor 4 carries out one stage of compression, press through in after compression heat steam cold-producing medium respectively through the first check valve 6-1 and the second check valve 6-2 with from intercooler 9 gas vent out press during saturated vapor refrigerant mixed is and press through heat steam cold-producing medium and enter in high voltage variable flow compressor 5 and carry out second level compression, high pressure superheated vapor cold-producing medium after compression is condensed into high pressure liquid refrigerant through condenser 7, in choke valve 8, throttling is enter in intercooler 9 after the saturated gas-liquid two phase refrigerant of middle pressure, middle pressure saturated vapor cold-producing medium participates in second level compression, middle pressure saturated liquid cold-producing medium then through in press liquid feeding pipeline 2 to cold storage freezer feed flow.
When cold storage freezer load is less, low pressure variable-flow compressor 4 and high voltage variable flow compressor 5 work simultaneously, realize the best high and low pressure volumetric ratio of system by the refrigerant flow of adjustment high voltage variable flow compressor 5, low pressure variable-flow compressor 4; When cold storage freezer load is larger, low pressure constant flow compressor 3, low pressure variable-flow compressor 4 and high voltage variable flow compressor 5 work simultaneously, by regulating the refrigerant flow of low pressure variable-flow compressor 4 and high voltage variable flow compressor 5, the best high and low pressure volumetric ratio of the system that realizes.Refrigeration system is divided into three phases by little refrigerant flow to large refrigerant flow transition: when needing low refrigerant flow, and low pressure variable-flow compressor 4 and high voltage variable flow compressor 5 work, and low pressure constant flow compressor 3 is shut down; When needing intermediate refrigerant flow, low pressure constant flow compressor 3 and high voltage variable flow compressor 5 work, and low pressure variable-flow compressor 4 is shut down; When needing high refrigerant flow, low pressure constant flow compressor 3, high voltage variable flow compressor 5 and low pressure variable-flow compressor 4 work simultaneously.The requirement of various load to refrigerant flow can be met by the second throttle middle not exclusively cooling variable-flow double-stage compressive refrigerating system of the variable-flow Two-stage Compression condensation unit composition be connected in parallel.
The effect of described first check valve 6-1 and the second check valve 6-2 is, when low pressure constant flow compressor 3 works, the second check valve 6-2 prevents cold-producing medium from refluxing through low pressure variable-flow compressor 4; When low compression set Pumps in Variable Water Volume System under Pressure contracting machine 4 works, the first check valve 6-1 prevents cold-producing medium from refluxing through low pressure constant flow compressor 3.
Low pressure constant flow compressor of the present invention is any one in screw compressor, rotor compressor, helical-lobe compressor, piston compressor, or other pattern compressor.Described low pressure variable-flow compressor and described high voltage variable flow compressor be screw compressor, rotor compressor, helical-lobe compressor, piston compressor any one, or other pattern compressor, variable-flow mode can be by the frequency conversion to alternating current generator or by regulating the time variant voltage of direct current generator, and cold-producing medium unloading-load time control mode also can be adopted to realize the Flow-rate adjustment of cold-producing medium.Described condenser is air-cooled condenser, water-cooled condenser, evaporative condenser or other pattern condenser.Described choke valve is any one in electric expansion valve, heating power expansion valve, capillary or orifice throttle, also can be that other can reduce the throttling arrangement of refrigerant pressure.Described intercooler can be plate type heat exchanger, double pipe heat exchanger or other pattern heat exchanger.
Variable-flow double-stage compressive refrigerating system of the present invention is when concrete utilization, and high pressure compressor and low pressure compressor can adopt the compressor of same rated input power, are conducive to the adjustment of system and are convenient to maintenance process simulation, more easily realizes the modularization of system simultaneously.
The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.