KR101936636B1 - Heat pump - Google Patents

Abstract

여기서, D₂는 제 2 튜브의 내경이고, D₁은 제 1 튜브의 내경이다.The present invention provides a heat exchanger comprising a first heat exchange unit having a first tube and a first fin coupled to the first tube, a second heat exchange unit having a second tube having an inner diameter smaller than that of the first tube, An indoor heat exchanger through which the refrigerant passes through the second tube and passes through the first tube during the cooling operation, the refrigerant passes through the first tube in the heating operation, and then passes through the second tube; And an indoor fan that flows indoor air through the first heat exchange unit after the indoor air passes through the second heat exchange unit. The inner diameter of the second tube is determined by Equation (1) There is an advantage that annular flow of the refrigerant having excellent heat transfer performance can be generated in the entire region of the heat exchanger.
[Formula 1]

Here, D ₂ is the inner diameter of the second tube, and D ₁ is the inner diameter of the first tube.

Description

Heat pump

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump, and more particularly to a heat pump in which an indoor heat exchanger has a combination of tubes having different inner diameters.

Generally, a heat pump includes a compressor, an outdoor heat exchanger, an expansion mechanism, and an indoor heat exchanger, and is used for cooling or heating the room, or for hot water supply.

In the heat pump, the outdoor heat exchanger functions as a condenser, the indoor heat exchanger functions as an evaporator, the indoor heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator during heating operation. The heat pump may comprise an indoor unit and an outdoor unit. The indoor unit can supply cool air to the room during cooling operation and can supply warm air to the room during heating operation.

The indoor heat exchanger may include a tube and a fin, and a plurality of tubes may be connected so that the refrigerant can flow. In order to improve the performance of the indoor heat exchanger, it is necessary to improve the heat transfer coefficient of the refrigerant flowing through the inside of the tube. To this end, the flow path through which the refrigerant passes can be appropriately branched so that a proper amount of refrigerant flows through the tube. These branches are important design factors that determine the performance of the indoor heat exchanger.

Conventionally, since the cooling and heating standard performance was important, the minute index was determined in consideration of the total refrigerant flow rate under the standard conditions. In recent years, the heat exchange performance in various conditions becomes important and it is required to improve the performance of the partial load with a small load have.

The heat pump according to the prior art has a branching design for the indoor heat exchanger considering only the standard conditions, so that the flow pattern in the tube under partial load forms a separate flow, resulting in a low heat transfer coefficient and a partial load condition in which the refrigerant flow is small Therefore, when the entire indoor heat exchanger is designed, there is a problem that the refrigerant side pressure loss is excessive and the heat transfer performance is low.

According to an aspect of the present invention, there is provided a heat pump including a first heat exchange unit having a first tube and a first fin coupled to the first tube, a second tube having an inner diameter smaller than that of the first tube, And a second heat exchanging unit having a second fin coupled to the tube, wherein the refrigerant passes through the first tube after passing through the second tube during the cooling operation, and the refrigerant passes through the first tube during the heating operation An indoor heat exchanger passing through the second tube; And an indoor fan for allowing room air to flow through the first heat exchange unit after passing through the second heat exchange unit, wherein an inner diameter of the second tube is determined by Equation (1).

[Formula 1]

Here, D ₂ is an inner diameter of the second tube, and D ₁ is an inner diameter of the first tube.

The present invention has an advantage that an annular flow of a refrigerant having excellent heat transfer performance can be generated in the entire region of the indoor heat exchanger under a partial load condition in which the refrigerant flow rate is small.

Further, there is an advantage that the cooling performance in the partial load can be improved while maintaining the performance under standard conditions in which the refrigerant flow rate is large.

1 is a configuration diagram of one embodiment of a heat pump according to the present invention.
FIG. 2 is a sectional view showing the inside of an indoor unit of a heat pump according to an embodiment of the present invention,
FIG. 3 is a cross-sectional view showing a separation flow and an annular flow inside the tube,
4 is a view showing an indoor heat exchanger of one embodiment of a heat pump according to the present invention in comparison with an indoor heat exchanger having three tubes of the same inner diameter provided with three tubes.
5 is a graph comparing the heat transfer performance of an indoor heat exchanger of an embodiment of the heat pump according to the present invention with the heat transfer performance of an indoor heat exchanger having three tubes of the same inner diameter,
FIG. 6 is a graph showing the amount of heat of evaporation according to the outer diameter of the second heat exchanger of the heat pump according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of one embodiment of a heat pump according to the present invention.

 Referring to FIG. 1, the heat pump may include a compressor 2, an outdoor heat exchanger 4, an indoor heat exchanger 6, an expansion mechanism 8, and a cooling / heating switching unit 10.

The compressor (2) can suck and compress the refrigerant and discharge it.

The outdoor heat exchanger (4) is capable of exchanging the outdoor air or the liquid heating medium with the refrigerant. The outdoor heat exchanger (4) can function as a condenser for condensing the refrigerant compressed in the compressor (2) during the cooling operation and can function as an evaporator for evaporating the refrigerant expanded in the expansion mechanism (8) during the heating operation. The outdoor heat exchanger (4) can heat-exchange the outdoor air flowing in the outdoor fan (5) with the refrigerant when the outdoor air is exchanged with the refrigerant. The outdoor fan (5) is located outdoors together with the outdoor heat exchanger (4) to allow outdoor air to flow to the outdoor heat exchanger (4).

The indoor heat exchanger (6) is capable of exchanging heat between indoor air and refrigerant. The indoor heat exchanger 6 can function as a condenser for condensing the refrigerant compressed in the compressor 2 during the cooling operation and can function as an evaporator for evaporating the refrigerant expanded in the expansion mechanism 8 during the heating operation. The indoor heat exchanger (6) can exchange indoor air flowing by the indoor fan (7) with the refrigerant. The indoor fan (7) can be located indoors together with the indoor heat exchanger (6) and can flow indoor air to the indoor heat exchanger (6).

The expansion mechanism (8) is installed between the outdoor heat exchanger (4) and the indoor heat exchanger (6) to expand the refrigerant.

The cooling / heating switching unit 10 can cause the refrigerant to circulate in the order of the compressor 2, the outdoor heat exchanger 4, the expansion mechanism 8, and the indoor heat exchanger 6 in the cooling operation or the defrost operation. The cooling / heating switching unit 10 can cause the refrigerant to circulate in the order of the compressor 2, the indoor heat exchanger 6, the expansion mechanism 8, and the outdoor heat exchanger 4 during the heating operation.

In the cooling / heating switching section 10, one four-way valve is capable of switching the flow direction of the refrigerant, and the plurality of opening / closing valves can also change the flow direction of the refrigerant.

The heat pump can be installed in the outdoor unit O, the compressor 2, the outdoor heat exchanger 4, the outdoor fan 5, the expansion mechanism 8 and the flow path switching unit 10, And the indoor fan (7) can be installed in the indoor unit (I).

FIG. 2 is a sectional view showing the interior of the indoor unit of the heat pump according to the present invention, and FIG. 3 is a cross-sectional view showing a separated flow and an annular flow inside the tube.

The indoor unit I may include an indoor unit casing 13 in which an indoor air inlet 11 and an indoor air outlet 12 are formed.

The indoor heat exchanger (6) can be installed inside the indoor unit casing (13).

The indoor heat exchanger (6) may include a plurality of heat exchange units (16) and (18) having tubes and fins.

The plurality of heat exchange units (16) and (18) may include a first heat exchange unit (16) and a second heat exchange unit (18). The second heat exchange unit 18 can be installed before the first heat exchange unit 16 in the flow direction of the room air and the room air can flow through the first heat exchange unit 16 after passing through the second heat exchange unit 18. [ Lt; / RTI >

The indoor fan 7 can cause the indoor air to flow through the first heat exchange unit 16 after passing through the second heat exchange unit 18. [ The second heat exchange unit 18 can be positioned closer to the indoor air intake port 11 than the first heat exchange unit 16. [ The indoor heat exchanger (6) includes a first indoor heat exchanger (6-1) positioned in front of the indoor fan (7) in the flow direction of the room air and vertically arranged, a first indoor heat exchanger A second indoor heat exchanger 6-2 disposed at an upper side of the second indoor heat exchanger 6-2 and inclined to be closer to the rear toward the upper end and a second indoor heat exchanger 6-2 located at a rear side of the second indoor heat exchanger 6-2, And a third indoor heat exchanger (6-3) arranged in a tilted manner. The first indoor heat exchanger 6-1 is provided with a plurality of first tubes 22 in a direction perpendicular to the first pins 24 and a second tube 32 extending in a direction perpendicular to the second pins 34 Respectively. The second indoor heat exchanger 6-2 includes a plurality of first tubes 22 arranged in an oblique direction with respect to the first fin 24 and a second tube 32 inclined with respect to the second fin 34 Direction. The third indoor heat exchanger 6-3 includes a plurality of first tubes 22 arranged in an oblique direction with respect to the first fin 24 and a second tube 32 inclined with respect to the second fin 34 Direction.

In the indoor heat exchanger 6, the refrigerant flow inside the tube can be divided into a seperated flow and an annular flow. As shown in Fig. 3 (a), due to the effect of gravity, the separated flow is a flow in which the liquid refrigerant is concentrated in the lower portion of the tube due to the effect of gravity, and the heat transfer coefficient is lower than the annular flow, Performance is bad. On the other hand, as shown in Fig. 3 (b), the annular flow is a flow in which the refrigerant is annularly distributed in the tube, has a high heat transfer coefficient, and has good heat transfer performance.

In the indoor heat exchanger (6), an annular flow having a high heat transfer coefficient is mainly generated in the cooling operation under the standard condition in which the refrigerant flow rate is large. However, in the cooling operation in the partial load operation in which the refrigerant flow rate is low, And in this case, the heat exchange performance of the indoor heat exchanger 6 can be lowered.

It is preferable that the indoor heat exchanger 6 forms an annular flow inside the tube even when a small refrigerant flow rate flows into the indoor heat exchanger 6 in order to improve the heat exchange performance in the partial load operation, It is preferable to use a tube having a small diameter in the low-temperature region. When the indoor heat exchanger 6 uses a tube having a small diameter in both the first heat exchanging unit 16 and the second heat exchanging unit 18 over the entire area, the refrigerant pressure loss is increased in the high- Thereby deteriorating performance. It is preferable that the indoor heat exchanger 6 has a tubular ratio and a length ratio of the tube that minimizes the refrigerant pressure loss while making the refrigerant flow into the annular flow.

The first heat exchange unit 16 may be configured as a fin-tube type heat exchange unit having a first tube 22 and a first fin 24 coupled to the first tube 22. The plurality of first tubes 22 may be disposed on the first fin 24. The longer the length of the first tubes 22 in the left and right direction and the greater the number of the first tubes 22, the greater the amount of heat transferred. The plurality of first tubes 22 may be connected in a U-band.

The second heat exchange unit 18 is composed of a pin-and-tube type heat exchange unit having a second tube 32 having an inner diameter smaller than that of the first tube 22 and a second pin 34 coupled to the second tube 32 . A plurality of the second tubes 32 may be disposed on the second fin 34. The longer the length of the second tubes 32 in the left and right direction and the larger the number of the second tubes 32, The plurality of second tubes 32 may be connected by a U-band.

The first tube 22 of the first heat exchanging unit 16 and the second tube 32 of the second heat exchanging unit 18 may be connected to each other through a tube connecting passage (not shown) in the indoor heat exchanger 6. The refrigerant flows through the first tube 22 after the refrigerant passes through the second tube 32 during the cooling operation of the indoor heat exchanger 6. After the refrigerant passes through the first tube 22 during the heating operation, (Not shown). The indoor heat exchanger 6 can have the first and second tubes 22 and 22 at the low temperature and the high temperature at the cooling operation, respectively.

The indoor heat exchanger 6 may be arranged such that the second tube 32 is disposed in one row on the second pin 34 and the first tube 22 is disposed on the first pin 24 in two or more rows. The height of the second fin 34 on which the second tube 32 is disposed may be lower than the height of the first fin 24 on which the first tube 22 is disposed.

The inner diameter of the second tube 32 can be determined by Equation 1 so that the indoor heat exchanger 6 has a pipe tube ratio that minimizes the refrigerant pressure loss while making the refrigerant flow into the annular flow.

[Formula 1]

Here, D ₂ is the inner diameter of the second tube 32, and D ₁ is the inner diameter of the first tube 22.

On the other hand, the number of the second tubes 32 and the length of the second tubes 32 in the indoor heat exchanger 6 can be determined by Equation (2).

[Formula 2]

Wherein, N ₂ is the number of the second tube (32), L ₂ is the length of the second tube (32), N ₁ is the first number, and, L ₁ is a first tube 22 of the tube 22 .

The number N ₂ and the length L ₂ of the second tubes 32 can be set so as to effectively suppress the increase of the refrigerant pressure loss when the refrigerant flow rate is large and to suppress the annular flow stably It can be set to be secured.

FIG. 4 is a view illustrating a heat pump according to an embodiment of the present invention, in which the indoor heat exchanger is compared with an indoor heat exchanger having three tubes of the same inner diameter, FIG. 5 is a graph showing the heat transfer performance of the heat exchanger according to an embodiment of the present invention FIG. 6 is a graph showing the heat of evaporation according to the outer diameter of the second heat exchanger of the heat pump according to the embodiment of the present invention. FIG. 6 is a graph comparing the heat transfer performance of an indoor heat exchanger having three tubes of the same inner diameter.

4 (a) is a side view of an indoor heat exchanger (hereinafter referred to as a 3-row indoor heat exchanger) having three tubes of the same inner diameter and FIG. 4 (b) (Hereinafter referred to as a small-diameter tube 1 row and a large-diameter tube 2 row row indoor heat exchanger). The three-row indoor heat exchanger shown in Fig. 4 (a) can generate excess flow in the foremost tube to be heat-exchanged first with air, while the large-sized tube 1 shown in Fig. 4 (b) The two-row indoor heat exchanger minimizes the separation flow in the foremost tube.

As shown in FIG. 5, the indoor heat exchanger 6 according to the present invention may have an evaporation heat amount of 105% as compared to the three-row indoor heat exchanger according to the inner diameter of the second tube 32, Condensation heat per hour can be 103%.

6, when the inner diameter of the second tube 32 is determined by Equation (1), the amount of heat of evaporation is calculated so that the tube has the same outer diameter as that of the three-row indoor heat exchanger 102% or more can be demonstrated.

6: Indoor heat exchanger 7: Indoor fan
16: first heat exchanging unit 18: second heat exchanging unit
22: first tube 24: first pin
32: second tube 34: second pin

Claims (3)

A second heat exchange unit having a first heat exchange unit having a first tube and a first fin coupled to the first tube, a second tube having an inner diameter smaller than that of the first tube, and a second fin coupled to the second tube, An indoor heat exchanger through which the refrigerant passes through the second tube and passes through the first tube during the cooling operation and the refrigerant passes through the first tube and then through the second tube during the heating operation;
And an indoor fan for passing room air through the first heat exchange unit after passing through the second heat exchange unit,
The indoor heat exchanger includes a first indoor heat exchanger positioned forward and vertically in the direction of the flow of the indoor air and a second indoor heat exchanger located on the upper side of the first indoor heat exchanger and inclined toward the rear toward the upper end And a third indoor heat exchanger positioned at a rear side of the second indoor heat exchanger and inclined toward the rear toward the lower end of the second indoor heat exchanger,
Wherein the first indoor heat exchanger has a plurality of first tubes arranged in a direction perpendicular to the first fin and a plurality of second tubes arranged in a direction perpendicular to the second fin,
Wherein the second indoor heat exchanger has a plurality of first tubes arranged in an oblique direction on the first fin and a plurality of second tubes arranged in an oblique direction on the second fin,
Wherein the third indoor heat exchanger has a plurality of first tubes arranged in an oblique direction on the first fin and a plurality of second tubes arranged in an oblique direction on the second fin,
Wherein the inner diameter of the second tube is determined by equation (1).
[Formula 1]

Here, D ₂ is an inner diameter of the second tube, and D ₁ is an inner diameter of the first tube. A second heat exchange unit having a first heat exchange unit having a first tube and a first fin coupled to the first tube, a second tube having an inner diameter smaller than that of the first tube, and a second fin coupled to the second tube, An indoor heat exchanger through which the refrigerant passes through the second tube and passes through the first tube during the cooling operation and the refrigerant passes through the first tube and then through the second tube during the heating operation;
And an indoor fan for passing room air through the first heat exchange unit after passing through the second heat exchange unit,
The indoor heat exchanger includes a first indoor heat exchanger positioned forward and vertically in the direction of the flow of the indoor air and a second indoor heat exchanger located on the upper side of the first indoor heat exchanger and inclined toward the rear toward the upper end And a third indoor heat exchanger positioned at a rear side of the second indoor heat exchanger and inclined toward the rear toward the lower end of the second indoor heat exchanger,
Wherein the first indoor heat exchanger has a plurality of first tubes arranged in a direction perpendicular to the first fin and a plurality of second tubes arranged in a direction perpendicular to the second fin,
Wherein the second indoor heat exchanger has a plurality of first tubes arranged in an oblique direction on the first fin and a plurality of second tubes arranged in an oblique direction on the second fin,
Wherein the third indoor heat exchanger has a plurality of first tubes arranged in an oblique direction on the first fin and a plurality of second tubes arranged in an oblique direction on the second fin,
Wherein the first tube is installed in two rows on the first pin,
The second tube is installed in one row on the second pin,
Wherein the inner diameter of the second tube is determined by equation (1).
[Formula 1]

Here, D ₂ is an inner diameter of the second tube, and D ₁ is an inner diameter of the first tube. 3. The method according to claim 1 or 2,
Wherein the number of the second tubes and the length of the second tubes are determined by Equation (2).
[Formula 2]

Here, N ₂ is the number of the second tubes, L ₂ is the length of the second tube, N ₁ is the number of the first tubes, and L ₁ is the length of the first tube.

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