KR101065501B1 - Compressor and air conditioner including the same - Google Patents

Abstract

The present invention relates to a compressor, wherein an inlet pipe through which working fluid enters the compressor and a discharge pipe through which the working fluid compressed from the compressor exits are installed, and a diameter of the inlet pipe is referred to as D _i , and a diameter of the discharge pipe. When D _o , the diameter ratio D _o / D _i is 0.5 to 1.0, and the inflow pipe satisfies the following equation.

(2σ _i η _i t _i ) / (D _i -0.8t _i )> Pse

Where σ _i is the allowable tensile stress of the inlet pipe (N / mm ² ), η _i is the welding efficiency of the inlet pipe, t _i is the thickness of the inlet pipe (mm), and Pse is the evaporation temperature of the working fluid. It means the saturated steam pressure according to.

Compressor, piping, diameter, thickness, saturated steam pressure

Description

COMPRESSOR AND AIR CONDITIONER INCLUDING THE SAME}

The present invention relates to an air conditioner having a compressor, and more particularly, to an inlet pipe and a discharge pipe of a working fluid connected to an inlet and an outlet of a compressor.

In general, a compressor is a mechanical device that receives power from a power generating device such as an electric motor and compresses the working fluid to increase the pressure by applying a compression work to a working fluid such as air or refrigerant, and is widely used throughout the industry. .

In particular, the compressor is an essential device used in an air conditioner such as an air conditioning system or a heating system, which maintains a proper temperature regardless of the outside air temperature.

In recent years, the cooling cycle and the heat pump cycle by implementing a single device, the popularity of the air-conditioning air conditioner (so-called heat pump) that can selectively perform the cooling and heating of the room has been increasing. Typically, the heat pump includes an indoor unit including a heat exchanger, a compressor, an outdoor unit including a heat exchanger, and an expander.

When used in the cooling mode, the indoor heat exchanger acts as an evaporator to evaporate the low-temperature and low-pressure liquid refrigerant passing through to absorb the heat in the room to form a cooling mechanism for the room. The medium-temperature and low-pressure refrigerant gas passing through the evaporator is again converted into high-temperature and high-pressure refrigerant gas through the compressor. In contrast, in the heating mode, the indoor heat exchanger acts as a condenser, so that hot and high-pressure gaseous refrigerant passes through the condenser while releasing heat into the room to form a heating mechanism for the room. That is, the outdoor unit is used as a condenser in summer, and used as an evaporator in winter.

The compressor of the air conditioner as described above includes an inlet pipe installed at the inlet through which the refrigerant enters and a discharge pipe installed at the outlet through which the refrigerant comes out. Conventionally, it has not been recognized whether the size (diameter) of the inlet pipe and the outlet pipe affects the efficiency of the compressor. That is, in determining the sizes of the inflow pipe and the discharge pipe, the efficiency of the compressor was not considered. Accordingly, the conventional compressor has a problem that the efficiency is lowered.

The present invention is to solve the above problems, the compressor having an inlet pipe and a discharge pipe having an optimal size that can withstand the pressure of the working fluid while optimizing the efficiency of the compressor and the air comprising the same In providing a harmonic.

In order to achieve the above object, the compressor according to the embodiment of the present invention is provided with an inlet pipe through which the working fluid enters the compressor and a discharge pipe through which the working fluid compressed from the compressor exits. Here, when the diameter of the inflow pipe is referred to as D _i , and the diameter of the discharge pipe is referred to as D _o , the diameter _{ratio Do} / D _i is 0.5 to 1.0.

In addition, the inflow pipe may satisfy the following equation.

(2σ _i η _i t _i ) / (D _i -0.8t _i )> Pse

Where σ _i is the allowable tensile stress of the inlet pipe (N / mm ² ), η _i is the welding efficiency of the inlet pipe, t _i is the thickness of the inlet pipe (mm), and Pse is the evaporation temperature of the working fluid. It means the saturated steam pressure according to.

In addition, the discharge pipe may satisfy the following equation.

(2σ _o η _o t _o ) / (D _o -0.8t _o )> Psc

Where σ _o is the allowable tensile stress (N / mm ² ) of the discharge pipe, η _o is the welding efficiency of the discharge pipe, t _o is the thickness of the discharge pipe, and Psc is the saturated steam pressure according to the condensation temperature of the working fluid. Means.

In addition, the thermal strain of the inlet pipe and the discharge pipe may be made 0.5% or less.

In addition, the present invention provides an air conditioner including the compressor as described above.

Compressor according to an embodiment of the present invention can increase the efficiency by optimally designing the size of the inlet pipe and the discharge pipe, it is also possible to increase the efficiency of the entire air conditioner by increasing the efficiency of the compressor. Due to the improved efficiency of the compressor and air conditioner, the operating costs of the entire system can also be reduced.

In addition, the compressor according to the embodiment of the present invention can prevent the breakage of the inlet pipe and the discharge pipe can provide the safety and reliability of the entire system.

Hereinafter, an outdoor unit of an air conditioner including a compressor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically showing an outdoor unit of an air conditioner according to an embodiment of the present invention, FIG. 2 is a pressure-enthalpy diagram of an air conditioner, and FIG. 3 is an inlet pipe and a discharge according to an embodiment of the present invention. A diagram schematically illustrating a compressor in which pipes are installed.

Referring to Figure 1, the outdoor unit 100 of the air conditioner (heat pump) according to an embodiment of the present invention is a heat exchanger 10, a heat exchange fan 20 to promote heat exchange between the refrigerant and the outside air, the refrigerant Compressor 30 and expander 40 to compress. The heat exchanger 10, the compressor 30, and the expander 40 are connected to a conduit 50 through which the refrigerant flows. In FIG. 1, the arrows indicate the direction in which the refrigerant flows. In the present embodiment, the arrow indicates the direction in which the refrigerant moves.

A gas-liquid separator 60 is installed at the front end of the compressor 30, and an oil separator 70 is installed at the rear end of the compressor 30. The gas-liquid separator 60 prevents liquid refrigerant from penetrating into the compressor 30, and the oil separator 70 separates oil from the refrigerant discharged from the compressor 30. An oil return pipe 52 is installed in the oil separator 70 to send oil that can flow into the compressor 30 to the front end of the compressor 30.

The direction switching valve 80 changes the conveying direction of the refrigerant when the cooling mode or the heating mode of the air conditioner is switched. The receiver 90 is installed at the rear end of the expander 40 to temporarily store the liquid refrigerant. In addition, the shutoff valve 54 is used to temporarily block the flow of the refrigerant such as repair of the air conditioner.

In the outdoor unit 100 of the air conditioner as described above, the compressor 30 is a key device for making refrigerant vapor of low temperature and low pressure into refrigerant vapor of high temperature and high pressure, and the efficiency of the compressor 30 is increased. It has a decisive impact on efficiency.

The performance of the compressor 30 is represented by isentropic efficiency, and isotropic efficiency is represented by the ratio of the isentropic compression days when the compression is reversibly and the actual compression days consumed for the compression. More specifically, referring to FIG. 2, the reversible compression is performed by the dotted line B-C 'process, and the actual compression is performed by the solid line B-C process. Therefore, the isentropic efficiency (μ) can be expressed as in Equation (1) below.

μ = (isoentropy compression day) / (actual compression day) = (h _{C '} -h _B ) / (h _C -h _B ) ...... (1)

Where h _B is enthalpy at point B, h _C is enthalpy at point _C and h _{C '} is enthalpy at point C'.

The isentropic efficiency of the compressor 30 expressed as described above is closely related to the diameter of the inlet pipe 32 (see FIG. 3) connected to the inlet of the compressor 30 and the discharge pipe 34 (see FIG. 3) connected to the outlet. There is a relationship. The inflow pipe 32 of the compressor 30 may be determined to be an appropriate size (diameter) according to the capacity of the entire system, and the change in the size (diameter) of the discharge pipe 34 accordingly may be a refrigerant discharged from the compressor 30. It affects the thermodynamic properties of. When the enthalpy, specific volume, and the like, which are thermodynamic properties of the refrigerant, are affected, the efficiency of the compressor 30 is affected, so that the inlet pipe 32 connected to the compressor 30 so as to optimize the isentropic efficiency of the compressor 30. There is a need to determine the size of the discharge pipe 34.

When the diameter (mm) of the inflow pipe (32) is referred to as D _i and the diameter (mm) of the discharge pipe (34) is referred to as D _O , the diameter ratio (D _o / D _i ) is expressed by Equation (2) below. If so, the isentropic efficiency of the compressor 30 is optimal. This will become more apparent with reference to Table 1 below.

_{0.5 ≤ D o / D i ≤1.0} ..................... (2)

Diameter of inlet pipe
(D _i , mm) Diameter of discharge pipe
(D _O , mm) Diameter ratio
(D _o / D _i ) Isotropic efficiency 25.40 9.52 0.3748 0.514 25.40 12.70 0.5000 0.736 25.40 15.88 0.6252 0.786 25.40 19.05 0.7500 0.804 25.40 22.23 0.8752 0.801 25.40 25.40 1.0000 0.764 25.40 28.58 1.1252 0.541

4 is a diagram illustrating isotropic efficiency of a compressor having an inflow pipe and an outflow pipe according to an embodiment of the present invention. Referring to FIG. 4, isotropic efficiency of the compressor 30 is based on a diameter ratio of 0.5 and 1.0. You can see the rapid change.

In addition, the inlet pipe 32 connected to the compressor 30 according to the embodiment of the present invention should be designed to have a pressure resistance to withstand the saturated steam pressure with respect to the evaporation temperature. Equation (3) is satisfied.

(2σ _i η _i t _i ) / (D _i -0.8t _i )> Pse ............. (3)

Where σ _i is the allowable tensile stress of the inlet pipe 32 (N / mm ² ), η _i is the welding efficiency of the inlet pipe 32, t _i is the thickness of the inlet pipe (mm), and Pse is It means the saturated steam pressure according to the evaporation temperature of working fluid.

In addition, the discharge pipe 34 connected to the compressor 30 according to the embodiment of the present invention should be designed to have a pressure resistance to withstand the saturated steam pressure with respect to the condensation temperature, for this purpose, the discharge pipe 34 is Equation (4) is satisfied.

(2σ _o η _o t _o ) / (D _o -0.8t _o )> Psc ............. (4)

Where σ _o is the allowable tensile stress (N / mm ² ) of the discharge pipe, η _o is the welding efficiency of the discharge pipe, t _o is the thickness of the discharge pipe, and Psc is the saturated steam pressure according to the condensation temperature of the working fluid. Means.

The compressor that satisfies the above formulas (1) to (3) can be provided with a rigid compressor piping in which isotropic efficiency is optimal and which is not damaged by the pressure of the refrigerant.

In addition, in designing the inlet pipe 32 and the discharge pipe 34 of the compressor 30, the properties of the material must also be sufficiently considered. In particular, when designing piping, it is required to have sufficient heat resistance to temperature changes. The change in temperature of an object causes a change in its volume, so when heat is applied to an object, the object causes thermal deformation to a reference point to which heat is applied. Such thermal strain y can be obtained by the following equation (5).

              y = δ / L = αΔT ..................... (5)

Here, δ is thermal deformation amount (mm), L is the length of the object (mm), α is the coefficient of thermal expansion (1 / ℃) and ΔT means the temperature difference (℃).

The compressor 30 is a device for compressing a low temperature and low pressure refrigerant into a high temperature and high pressure refrigerant, and is accompanied by a temperature change after the compression of the refrigerant. Since the heat deformation of the inlet pipe 32 and the discharge pipe 34 due to the change in temperature affects the efficiency of the entire system, the heat deformation rate of the inlet pipe 32 and the discharge pipe 34 is minimized. This must be determined. To this end, the thermal strain of the inlet pipe 32 and the discharge pipe 34 connected to the compressor 30 according to the embodiment of the present invention is greater than 0% and less than 0.5%.

In the above, the embodiment in which the compressor is applied to the air conditioner has been described, but the present invention is not limited thereto and may be applied to all industrial apparatuses in which the compressor is used.

While the preferred embodiments of the present invention have been described so far, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

1 is a view schematically showing an outdoor unit of an air conditioner according to an embodiment of the present invention.

2 is a pressure-enthalpy diagram of an air conditioner.

3 is a view schematically showing a compressor provided with an inflow pipe and a discharge pipe according to an embodiment of the present invention.

4 is a view showing the isentropic efficiency of the compressor provided with the inlet pipe and the outlet pipe according to an embodiment of the present invention.

Claims (6)

A compressor for compressing a working fluid at high pressure, An inlet pipe through which the working fluid enters the compressor and a discharge pipe through which the working fluid compressed from the compressor comes out, When the diameter of the inflow pipe is referred to as D _i , and the diameter of the discharge pipe is referred to as D _o , the diameter ratio (D _o / D _i ) is 0.5 to 1.0, Compressor characterized in that the inlet pipe satisfies the following equation. (2σ _i η _i t _i ) / (D _i -0.8t _i )> Pse Where σ _i is the allowable tensile stress of the inlet pipe (N / mm ² ), η _i is the welding efficiency of the inlet pipe, t _i is the thickness of the inlet pipe (mm), and Pse is the evaporation temperature of the working fluid. It means the saturated steam pressure according to. The method of claim 1, Compressor, characterized in that the thermal strain of the inlet pipe and the discharge pipe is greater than 0% and less than 0.5%. An air conditioner, comprising the compressor according to claim 1. A compressor for compressing a working fluid at high pressure, An inlet pipe through which the working fluid enters the compressor and a discharge pipe through which the working fluid compressed from the compressor comes out, When the diameter of the inflow pipe is referred to as D _i , and the diameter of the discharge pipe is referred to as D _o , the diameter ratio (D _o / D _i ) is 0.5 to 1.0, And said discharge pipe satisfies the following equation. (2σ _o η _o t _o ) / (D _o -0.8t _o )> Psc Where σ _o is the allowable tensile stress (N / mm ² ) of the discharge pipe, η _o is the welding efficiency of the discharge pipe, t _o is the thickness of the discharge pipe, and Psc is the saturated steam pressure according to the condensation temperature of the working fluid. Means. 5. The method of claim 4, Compressor, characterized in that the thermal strain of the inlet pipe and the discharge pipe is greater than 0% and less than 0.5%. An air conditioner, comprising the compressor according to claim 4.

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