Two-stage double-impeller opposed magnetic suspension compressor heat pump unit

Abstract

The utility model discloses a two-stage double-impeller opposed magnetic suspension compressor heat pump unit. A heat pump system has higher efficiency when running under a design working condition and a bias working condition. Comprising an evaporator, a condenser, a first-stage heat pump compressor and a second-stage heat pump compressor, the first-stage heat pump compressor and the second-stage heat pump compressor each comprise a magnetic suspension motor, and the two output ends of the magnetic suspension motors are connected with symmetrical compressor assemblies which are controlled in a frequency conversion mode respectively; a working medium outlet of the evaporator is connected with two working medium pipelines, the two working medium pipelines are connected with two compressor assemblies of the first-stage heat pump compressor, and the two compressor assemblies of the first-stage heat pump compressor are correspondingly connected with two compressor assemblies of the second-stage heat pump compressor in series through the two working medium pipelines. The two compressor parts of the second-stage heat pump compressor are connected with a working medium inlet of the condenser through two working medium pipelines, and a working medium outlet of the condenser is connected with a working medium inlet of the evaporator through an expansion valve.

Description

Technical Field

[0001] The utility model relates to the technical field, in particular to a two-stage double-impeller opposed magnetic levitation compressor heat pump unit, which is applicable to heat pump units using media such as R134A and R1233ZD for refrigeration and heating. Background Technique

[0002] Conventional two-stage compressor heat pump units adopt a design of a single / multi-motor suspended double-cantilever two-stage series heat pump compressor with guide vanes. Since the heat pump unit is getting larger and larger, the power of a single motor is insufficient, so two identical double-cantilever two-stage series heat pump compressors with guide vanes are adopted. For the double-cantilever two-stage series heat pump compressor with guide vanes, the two-stage matching design is very difficult during the design process. When operating under off-design conditions, the first inlet air flow angle is adjusted through the guide vane to match the operating state of the first-stage compressor. However, there is no guide vane control for the second stage, resulting in two-stage matching in an inefficient working condition. Moreover, the adjustment process of this design is complex and requires a large number of complex logics for adjustment. At the same time, for the two impellers of the two-stage series compressor, the bearing forces are inconsistent, and generally the thrust gap is relatively large. Therefore, it is difficult to balance the thrust, and the loss caused by balancing the thrust is also relatively large. The utility model designs a two-stage compression, double-impeller opposed magnetic levitation compressor heat pump unit. Summary of the Invention

[0003] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a two-stage double-impeller opposed magnetic levitation compressor heat pump unit, and the heat pump system has high efficiency both in the design working condition and off-design operation.

[0004] The purpose of the utility model is realized as follows:

[0005] A two-stage double-impeller opposed magnetic levitation compressor heat pump unit includes an evaporator, a condenser, and also includes a first-stage heat pump compressor and a second-stage heat pump compressor. The first-stage heat pump compressor and the second-stage heat pump compressor both include a magnetic levitation motor. The two output ends of the magnetic levitation motor are connected to compressor parts that are mirror-symmetrically arranged and have the same specifications. The first-stage heat pump compressor and the second-stage heat pump compressor are respectively controlled by frequency converters;

[0006] Two working medium pipelines are connected to the working medium outlet of the evaporator. The two working medium pipelines are connected to the two compressor parts of the first-stage heat pump compressor. The two compressor parts of the first-stage heat pump compressor are correspondingly connected in series with the two compressor parts of the second-stage heat pump compressor through two working medium pipelines. The two compressor parts of the second-stage heat pump compressor are connected to the working medium inlet of the condenser through two working medium pipelines. The working medium outlet of the condenser is connected to the working medium inlet of the evaporator through an expansion valve to form a closed cycle.

[0007] Preferably, the evaporator has a heat source inlet and a heat source outlet for the heat source to enter and exit; the condenser has a cold source inlet and a cold source outlet for the cold source to enter and exit.

[0008] Preferably, the housing of the magnetic levitation motor is fixedly connected to the housing of the corresponding compressor unit through bolts and sealed with rubber rings; a magnetic bearing controller and a motor terminal box are also fixedly installed on the housing of the magnetic levitation motor through bolts and sealed with sintered plugs, so as to form a closed space in the motor cavity of the magnetic levitation motor.

[0009] Preferably, the first-stage heat pump compressor and the second-stage heat pump compressor are installed above the evaporator, and the frequency converters of the first-stage heat pump compressor and the second-stage heat pump compressor are integrated together.

[0010] Due to the adoption of the above technical solutions, the utility model has the following beneficial effects:

[0011] 1. The compressor heads suspended at both ends of the single magnetic levitation motor adopted by the utility model are consistent, which can offset the pneumatic thrust by 100%. There is no need to design a complex structure to balance the thrust, fundamentally solving the problem of thrust balance of the two-stage series compressor, and greatly reducing the design difficulty and power consumption of the magnetic levitation thrust bearing;

[0012] 2. The utility model adopts two double-cantilever impeller opposed magnetic levitation compressors in series, which can realize the separate control of the two compressors, can well match the parameters of the heat pump system, and solves the problem of low efficiency caused by poor matching of the two-stage compressors during variable operating conditions of the two-stage series compressor;

[0013] 3. The utility model adopts two-stage frequency conversion regulation, which can well broaden the flow range, does not require an additional inlet guide vane structure, avoids the possibility of blade breakage caused by interference between the inlet guide vane and the impeller, and reduces the shutdown risk brought by inlet guide vane failure at the same time;

[0014] 4. The utility model adopts an oil-free magnetic levitation compressor to realize the oil-free design of the heat pump system, does not require an additional complex oil separation system, and avoids the pollution of the refrigerant working medium by lubricating oil and the decline of heat transfer performance caused by oil in the heat exchanger;

[0015] 5. The utility model adopts a closed magnetic levitation motor cooled by refrigerant, which reduces the difficulty of compressor seal design. The motor can be cooled by the leaked refrigerant, and the energy generated by the motor heating can be recovered; no additional cooling facilities are required, reducing the complexity of the system and the faults caused by motor cooling problems;

[0016] 6. The utility model adopts an integrated design, with the compressor placed above the evaporator. It has a regular shape and a compact structure, without cleaning dead corners, and can be hoisted integrally as a skid, solving the problems of large occupied space, cleaning dead zones, and the need for multiple separate hoists during hoisting in other forms of bases and oil station structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the utility model;

[0018] Figure 2 It is a schematic structural diagram of a heat pump compressor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] An embodiment of a two-stage double-impeller opposed magnetic levitation compressor heat pump unit includes an evaporator 9 and a condenser 5. The evaporator has a heat source inlet and a heat source outlet for the heat source to enter and exit. The condenser has a cold source inlet and a cold source outlet for the cold source to enter and exit. It also includes a first-stage heat pump compressor 6 and a second-stage heat pump compressor 8. Both the first-stage heat pump compressor 6 and the second-stage heat pump compressor include a magnetic levitation motor 14. The two output ends of the magnetic levitation motor are connected to compressor assemblies that are mirror-symmetrically arranged and have the same specifications, namely compressor assembly A11 and compressor assembly B15. The first-stage heat pump compressor 6 and the second-stage heat pump compressor 8 are respectively controlled by a frequency converter 10. Two working fluid pipes are connected to the working fluid outlet of the evaporator 9. The two working fluid pipes are connected to the two compressor assemblies of the first-stage heat pump compressor 6. The two compressor assemblies of the first-stage heat pump compressor 6 are correspondingly connected in series with the two compressor assemblies of the second-stage heat pump compressor 8 through two working fluid pipes. The two compressor assemblies of the second-stage heat pump compressor 8 are connected to the working fluid inlet of the condenser 5 through two working fluid pipes. The working fluid outlet of the condenser 5 is connected to the working fluid inlet of the evaporator through an expansion valve 7 to form a closed cycle.

[0020] Specifically:

[0021] Figure 1It shows the schematic structure of the whole heat pump system; through an integrated design, each component of the heat pump system is connected and integrated into one. The heat source enters the evaporator 9 through the heat source inlet 1, exchanges heat with the working medium, and then is discharged through the heat source outlet 2 to release heat energy; the working medium absorbs heat in the evaporator 9 and enters the first-stage heat pump compressor 6 through the pipes at both ends. After being pressurized and heated by the compressors at both ends, the working medium enters the second-stage heat pump compressor 8. After being heated and pressurized by the second-stage compressors at both ends 8, it enters the condenser 5 to exchange heat and condense with the cold source. After condensation, it is depressurized and cooled through the expansion valve 7 to form a gas-liquid two-phase, and then enters the evaporator to absorb heat, forming a closed cycle. The cold source enters the condenser 5 through the cold source inlet 3, exchanges heat and its temperature rises, and is discharged through the cold source outlet 4 to complete the heat absorption process. The frequency converter 10 is integrated with two motor frequency converters into a cabinet, which respectively controls the first- and second-stage heat pump compressors, realizes the stepless speed change of the heat pump compressors, and well matches the operating conditions of the two-stage compressors to make them operate efficiently.

[0022] Figure 2 It shows the structure of a two-stage double-impeller opposed magnetic levitation compressor; the compressor component A and the compressor component B are mirror images of each other, with the same aerodynamic performance, the same magnitude of thrust on both sides, and opposite directions, which can completely balance the thrust of the rotor structure. The compressor component is connected to the magnetic levitation motor through bolts and sealed with rubber rings. The magnetic levitation bearing controller 13 and the motor junction box 12 are both connected to the magnetic levitation motor through bolts and sealed with sintered plugs to ensure that a closed space is formed inside the motor cavity.

[0023] The compressor adopts two double-cantilever impeller opposed magnetic levitation compressors connected in series. The compressor heads suspended on the left and right sides of the compressor are the same, and the two compressors are separately controlled by a frequency converter. It realizes that the heat pump system has high efficiency both in the design condition and off-design condition.

[0024] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A two-stage double-impeller opposed magnetic levitation compressor heat pump unit, comprising an evaporator and a condenser, characterized in that: It further includes a first-stage heat pump compressor and a second-stage heat pump compressor. Both the first-stage heat pump compressor and the second-stage heat pump compressor include a magnetic levitation motor. The two output ends of the magnetic levitation motor are connected to compressor sleeves that are mirror-symmetrically arranged and have the same specifications. The first-stage heat pump compressor and the second-stage heat pump compressor are respectively controlled by frequency converters. Two working medium pipes are connected to the working medium outlet of the evaporator. The two working medium pipes are connected to the two compressor sleeves of the first-stage heat pump compressor. The two compressor sleeves of the first-stage heat pump compressor are correspondingly connected in series with the two compressor sleeves of the second-stage heat pump compressor through two working medium pipes. The two compressor sleeves of the second-stage heat pump compressor are connected to the working medium inlet of the condenser through two working medium pipes. The working medium outlet of the condenser is connected to the working medium inlet of the evaporator through an expansion valve to form a closed cycle.

2. The two-stage double-impeller opposed magnetic levitation compressor heat pump unit according to claim 1, characterized in that: The evaporator has a heat source inlet and a heat source outlet for the heat source to enter and exit; the condenser has a cold source inlet and a cold source outlet for the cold source to enter and exit.

3. A two-stage double impeller opposed magnetic levitation compressor heat pump unit according to claim 1, characterized in that: The outer shell of the magnetic levitation motor is fixedly connected to the outer shell of the corresponding compressor sleeve through bolts and is sealed with a rubber ring; a magnetic levitation bearing controller and a motor terminal box are also fixedly installed on the outer shell of the magnetic levitation motor through bolts and are sealed with a sintered plug, so as to form a closed space in the motor cavity of the magnetic levitation motor.

4. A two-stage double-impeller opposed magnetic levitation compressor heat pump unit according to claim 1, characterized in that: The first-stage heat pump compressor and the second-stage heat pump compressor are installed above the evaporator, and the frequency converters of the first-stage heat pump compressor and the second-stage heat pump compressor are integrated together.

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