CN205641653U - Cascade refrigeration system of unsteady flow volume simplex matter sharing condenser and evaporimeter - Google Patents

Abstract

The utility model discloses a cascade refrigeration system in which a single working substance with variable flow rate shares a condenser and an evaporator. Each refrigerating compressor unit of the utility model is composed of a refrigerating compressor and four electromagnetic valves. Three solenoid valves and the fourth solenoid valve, the first solenoid valve connected to each refrigeration compressor is connected in parallel to the inlet of the condenser, and the second solenoid valve connected to each refrigeration compressor is connected in parallel to the inlet of the condensing side of the condensing evaporator connection, the third solenoid valve connected to each refrigeration compressor is connected in parallel to the outlet of the evaporation side of the condensing evaporator, and the fourth solenoid valve connected to each refrigeration compressor is connected in parallel to the outlet of the evaporator; the outlet of the condenser is The first-stage throttling valve is connected to the inlet of the evaporating side of the condensing evaporator, and the outlet of the condensing side of the condensing evaporator is connected to the inlet of the evaporator through a low-temperature throttling valve. The cascade refrigeration system of the utility model is composed of a single working medium, without expansion vessels and other devices, and the system structure is simple.

Description

Cascade Refrigeration System with Variable Flow and Single Working Substance Sharing Condenser and Evaporator

technical field

The utility model relates to a refrigeration unit, more specifically, to a multi-head cascade refrigeration cycle system, which is used to improve the efficiency of the cascade refrigeration system, and at the same time, the refrigerant flow rate of the refrigeration system can be adjusted.

Background technique

The single-stage compression refrigeration system is not suitable for low-temperature refrigeration systems with a compression ratio (the ratio of the discharge pressure to the suction pressure) greater than 12 due to the limitation of the suction and discharge compression ratio of the compressor. In the prior art, when the compression ratio is greater than 12, a two-stage compression refrigeration system is usually used. The two-stage compression refrigeration unit can be driven by a motor, or it can be realized by combining multiple heads. However, the high and low pressure of these two methods are interoperable, and the oil return problem of the compressor is not easy to solve.

Cascade refrigeration systems are also a good solution when cooling at lower temperatures is required. The heat is absorbed by the working fluid of the low-temperature refrigeration system, and transferred to the condensing evaporator connecting the low-temperature refrigeration system and the high-temperature refrigeration system, and then the heat is transferred to the environment by the high-temperature refrigeration system working fluid. This traditional cascade refrigeration system consists of two working fluids, the high-temperature refrigeration system uses a high-temperature refrigerant, and the low-temperature refrigeration system uses a low-temperature refrigerant. However, since the cryogenic working medium is in a supercritical state at room temperature, an expansion vessel is usually installed in the low-temperature refrigeration system, which makes the system complex and difficult to realize variable working medium flow control.

Utility model content

The utility model aims to overcome the defects in the prior art, and provides a cascade refrigeration cycle system with multiple heads and single working medium, which is used to improve the efficiency of the cascade refrigeration system, and at the same time, the flow rate of the working medium of the refrigeration system can be adjusted.

The utility model is realized through the following technical solutions:

A cascade refrigeration system with a variable flow single working medium sharing a condenser and an evaporator, including multiple refrigeration compressor units, condensers, condensing evaporators, evaporators, high-temperature stage throttle valves and low-temperature stage throttle valves, each The refrigeration compressor unit is composed of a refrigeration compressor, a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve. The exhaust ends of the refrigeration compressors are respectively connected to the first solenoid valve and the second solenoid valve. The suction end of the refrigeration compressor is respectively connected to the third solenoid valve and the fourth solenoid valve. The first solenoid valve connected to each refrigeration compressor is connected in parallel to the inlet of the condenser, and the second solenoid valve connected to each refrigeration compressor is connected to the inlet of the condenser. The valves are connected in parallel to the inlet of the condensing side of the condensing evaporator, the third solenoid valve connected to each refrigeration compressor is connected in parallel to the outlet of the evaporating side of the condensing evaporator, and the fourth solenoid valve connected to each refrigeration compressor is connected in parallel to the evaporator The outlet of the condenser is connected to the outlet of the condensing evaporator through the high-temperature throttling valve, and the condensing side outlet of the condensing evaporator is connected to the inlet of the evaporator through the low-temperature throttling valve.

When the refrigeration compressor is used as a high-temperature refrigeration system compressor, the first solenoid valve and the third solenoid valve are opened, and the second solenoid valve and the fourth solenoid valve are closed. At this time, the refrigeration compressor compresses the working medium and passes through the first solenoid valve. Enter the condenser to condense, the condensed working fluid is throttled by the high-temperature stage throttle valve, enters the condensing evaporator to evaporate, absorbs the condensation heat of the low-temperature stage, and then returns to the compressor through the third solenoid valve; when the refrigeration compressor is used as a low-temperature When the refrigeration system compressor is in the second stage, the second solenoid valve and the fourth solenoid valve are opened, and the first solenoid valve and the third solenoid valve are closed. At this time, the refrigeration compressor compresses the working fluid and enters the condensing evaporator through the second solenoid valve to condense. , to dissipate heat to the high-temperature stage, and the condensed working fluid is throttled by the low-temperature stage throttle valve and enters the evaporator to evaporate, resulting in refrigeration, and then returns to the compressor through the fourth solenoid valve.

The refrigeration compressor is any one of scroll compressor, rotor compressor, screw compressor, piston compressor or other types of refrigeration compressors, and the variable flow mode is adjusted by AC frequency conversion or DC frequency conversion, and industrial The flow regulation of working fluid is realized by means of mass unloading and loading.

The condenser is an air-cooled condenser, a water-cooled condenser or an evaporative condenser.

The condensing evaporator is a plate heat exchanger or a casing heat exchanger.

The evaporator is air-cooled and solution-cooled.

The high-temperature throttling valve and the low-temperature throttling valve are electronic expansion valves, thermal expansion valves, capillary or orifice throttling devices.

The solenoid valve can be replaced by a manual stop valve, a ball valve, etc.

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

1. The system is flexible: the refrigeration compressors in the cascade refrigeration system of the present utility model can realize the mutual conversion between the high-temperature refrigeration compressor and the low-temperature refrigeration compressor through the opening or closing of the solenoid valves at the suction end and the exhaust end. That is, any refrigeration compressor in the system can be used as a high-temperature refrigeration compressor or a low-temperature refrigeration compressor, which is convenient for inter-stage energy adjustment.

2. The system is simple: the cascade refrigeration system of the utility model is composed of a single working medium, and does not need devices such as expansion vessels, and the system structure is simple.

3. High efficiency: due to the control of variable working medium flow, the ratio of working medium flow in the high-temperature refrigeration system and the low-temperature refrigeration system is reasonable, and the system efficiency is high.

4. Solve the oil return problem of the compressor: the high-temperature refrigeration system of the utility model is isolated from the low-temperature refrigeration system, which solves the problem of uneven oil return when a two-stage compression cycle system is used.

Description of drawings

Fig. 1 is a schematic diagram of a cascade refrigeration system in which a variable-flow single-working medium shares a condenser and an evaporator according to the present invention.

In the figure: 1. refrigeration compressor, 2-1. first solenoid valve, 2-2. second solenoid valve, 2-3. third solenoid valve, 2-4. fourth solenoid valve, 3. condenser, 4-1. High temperature level throttle valve, 4-2. Low temperature level throttle valve, 5. Condensing evaporator, 6. Evaporator.

detailed description

The utility model is described in detail below in conjunction with accompanying drawing and specific embodiment.

Example 1

Fig. 1 is a schematic diagram of a cascaded refrigeration system with a variable flow single working substance sharing a condenser and an evaporator of the present invention, consisting of multiple refrigeration compressors 1, a condenser 3, a condensing evaporator 5, an evaporator 6, and a high-temperature throttling valve 4-1 and low-temperature throttling valve 4-2, the exhaust end of each refrigeration compressor 1 is respectively connected with a first solenoid valve 2-1 and a second solenoid valve 2-2, each refrigeration compressor 1 The suction end of the compressor 1 is respectively connected with a third solenoid valve 2-3 and a fourth solenoid valve 2-4, and the first solenoid valve 2-1 connected to each refrigeration compressor 1 is connected in parallel with the The inlet of the condenser 3 is connected, and the second electromagnetic valve 2-2 connected to each of the refrigeration compressors 1 is connected in parallel with the inlet of the condensation side of the condensing evaporator 5, and each of the refrigeration compressors The third solenoid valve 2-3 connected to 1 is connected in parallel to the outlet of the evaporation side of the condensation evaporator 5, and the fourth solenoid valve 2-4 connected to each refrigeration compressor 1 is connected in parallel to the The outlet of the evaporator 6 is connected; the outlet of the condenser 3 is connected to the inlet of the evaporation side of the condensing evaporator 5 through the high-temperature stage throttle valve 4-1, and the outlet of the condensing side of the condensing evaporator 5 passes through the The low temperature stage throttling valve 4-2 is connected with the inlet of the evaporator 6 .

When the first solenoid valve 2-1 and the third solenoid valve 2-3 connected to the refrigeration compressor 1 are opened, the second solenoid valve 2-2 and the fourth solenoid valve 2-4 are closed At this time, the system connected to the refrigeration compressor 1 is the high-temperature stage of the cascade refrigeration system. At this time, the refrigeration compressor 1 compresses the working fluid into the condenser 3 through the first solenoid valve 2-1 Condensate, enter the condensing evaporator 5 to evaporate after being throttled by the high-temperature stage throttle valve 4-1, absorb the condensation heat of the low-temperature stage, and the evaporated working medium returns to the condensate through the third solenoid valve 2-3 In the refrigeration compressor 1; when the second solenoid valve 2-2 and the fourth solenoid valve 2-4 connected to the refrigeration compressor 1 are opened, the first solenoid valve 2-1 and the When the third electromagnetic valve 2-3 is closed, the system connected to the refrigeration compressor 1 is the low-temperature stage of the cascade refrigeration system. At this time, the refrigeration compressor 1 compresses the working fluid through the second electromagnetic valve 2- 2 to condense in the condensing evaporator 5, dissipate heat to the high-temperature stage, and enter the evaporator 6 to evaporate after being throttled by the low-temperature stage throttle valve 4-2 to generate refrigeration, and then pass through the fourth electromagnetic Valves 2-4 go back to refrigeration compressor 1.

In the embodiment of the utility model, only the cascade refrigeration system with shared condenser and evaporator is listed. In practical application, cascade refrigeration system with shared condenser and parallel evaporator and cascade refrigeration system with parallel condenser and shared evaporator can be used. .

Any compressor of the variable-flow single-substance cascade refrigeration system of the utility model can be switched to a high-temperature refrigeration system or a low-temperature refrigeration system compressor through a valve, and the high-temperature refrigeration system can be realized by starting and stopping the compressor or motor frequency conversion. Flow changes in refrigeration systems or cryogenic stage refrigeration systems.

When the variable-flow single-substance cascade refrigeration system of the utility model is used in practice, the refrigeration compressor can partially or completely use a fixed-frequency refrigeration compressor to reduce investment.

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 variable-flow either simplex matter common condenser and the cascade refrigeration system of vaporizer, it is characterised in that Including multiple stage refrigeration compressor set, condenser, condenser/evaporator, vaporizer, high-temperature level choke valve and low Temperature level choke valve, every refrigeration compressor set by refrigeration compressor, the first electromagnetic valve, the second electromagnetic valve, 3rd electromagnetic valve, the 4th electromagnetic valve composition, the exhaust end of refrigeration compressor connect respectively the first electromagnetic valve and Second electromagnetic valve, the suction end of every refrigeration compressor connects the 3rd electromagnetic valve and the 4th electromagnetic valve respectively, The first electromagnetic valve connected on every refrigeration compressor is connected with the import of condenser after being connected in parallel, every It is connected with condenser/evaporator condensation side import after the second electromagnetic valve parallel connection connected on refrigeration compressor, every It is connected with the outlet of condenser/evaporator evaporation side after the 3rd electromagnetic valve parallel connection connected on refrigeration compressor, every It is connected with the outlet of vaporizer after the 4th electromagnetic valve parallel connection connected on refrigeration compressor；The outlet of condenser Being connected with condenser/evaporator evaporation side import through high-temperature level choke valve, the outlet of condenser/evaporator condensation side is passed through Low-temperature level choke valve is connected with evaporator.

Variable-flow either simplex matter common condenser the most according to claim 1 and the cascade refrigeration of vaporizer System, it is characterised in that described refrigeration compressor is screw compressor, rotor compressor, screw compression Machine or piston compressor.

Variable-flow either simplex matter common condenser the most according to claim 1 and the overlapping system of vaporizer Cooling system, it is characterised in that described condenser is air-cooled condenser, water-cooled condenser or evaporating type condensing Device.

Variable-flow either simplex matter common condenser the most according to claim 1 and the overlapping system of vaporizer Cooling system, it is characterised in that described condenser/evaporator is plate type heat exchanger or double pipe heat exchanger.

Variable-flow either simplex matter common condenser the most according to claim 1 and the overlapping system of vaporizer Cooling system, it is characterised in that described vaporizer is air-cooled or solution refrigerating formula.

Variable-flow either simplex matter common condenser the most according to claim 1 and the overlapping system of vaporizer Cooling system, it is characterised in that described high-temperature level choke valve and low-temperature level choke valve are electric expansion valve, heat Power expansion valve, capillary tube or throttle orifice plate apparatus.