WO2015004720A1

WO2015004720A1 - Heat exchanger, and air conditioner

Info

Publication number: WO2015004720A1
Application number: PCT/JP2013/068677
Authority: WO
Inventors: 石橋　晃; 拓也松田; 岡崎　多佳志; 厚志望月
Original assignee: 三菱電機株式会社
Priority date: 2013-07-08
Filing date: 2013-07-08
Publication date: 2015-01-15
Also published as: JPWO2015005352A1; WO2015005352A1; CN105452794A; EP3021064B1; EP3021064A4; EP3021064A1; US20160298886A1

Abstract

This heat exchanger is characterized by being provided with: a plurality of fins (1) which are disposed with a clearance therebetween, which have a fluid flowing therebetween, and in which passages are formed, said passages having, flowing therethrough, a medium for performing heat exchange with the fluid; and a pair of headers which respectively connect both ends of the plurality of fins (1). The heat exchanger is further characterized in that, in cases when Fp is the fin pitch, i.e. the clearance between neighbouring fins (1), and Ft is the fin thickness, the plurality of fins (1) satisfy the relationship 3 ≤ Fp/Ft ≤ 21.

Description

Heat exchanger and air conditioner

The present invention relates to a heat exchanger and an air conditioner including the heat exchanger.

In the conventional technology, a heat exchanger having a plurality of flat multi-channel heat transfer tubes between headers arranged at intervals is proposed (see, for example, Patent Document 1).

Japanese translation of PCT publication No. 2008-528943 (summary)

In the technique described in Patent Document 1, no consideration is given to the thickness and tube pitch of a plurality of flat multi-channel heat transfer tubes (a plurality of fins having channels formed therein).
For this reason, if the thickness and pipe pitch of the plurality of fins are not appropriate, there is a problem that the heat exchange performance of the heat exchanger decreases.
For example, if the fins are too thick, the flow path area increases, but the ventilation resistance of the air passing between the plurality of fins increases and the heat exchange performance decreases. Conversely, if the fin thickness is reduced, the airflow resistance of the air passing between the plurality of fins is reduced, but the flow path area is reduced and the heat exchange performance is reduced.

The present invention has been made to solve the above-described problems, and provides a heat exchanger and an air conditioner that can improve heat exchange performance.

The heat exchanger according to the present invention includes a plurality of fins in which fluids flow between them and a flow path through which a medium that exchanges heat with the fluid flows is formed, and both ends of the plurality of fins A plurality of fins, wherein the fins have a pitch of Fp as the gap between adjacent fins, and Ft is the thickness of the fins, and 3 ≦ Fp / Ft ≦ 21 It is characterized by satisfying the relationship.

The present invention provides a pair of fins that are arranged with a space therebetween, in which a fluid flows between them and in which a channel through which a medium that exchanges heat with the fluid flows is formed, and to which both ends of the plurality of fins are connected. In the heat exchanger provided with the header, the heat exchange performance can be improved.

It is a perspective view which shows the heat exchanger which concerns on Embodiment 1 of this invention. It is a side view which shows the heat exchanger which concerns on Embodiment 1 of this invention. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. It is an enlarged view which shows the B section of FIG. It is a figure which shows the performance characteristic of the heat exchanger which concerns on Embodiment 1 of this invention. It is a refrigerant circuit diagram of the air conditioner according to Embodiment 1 of the present invention. It is a perspective view which shows the heat exchanger which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the arrangement | sequence of the fin of the heat exchanger which concerns on Embodiment 2 of this invention. It is a perspective view which shows the heat exchanger which concerns on Embodiment 3 of this invention. It is sectional drawing which shows the inlet side header of the heat exchanger which concerns on Embodiment 3 of this invention. It is a figure which shows the inner tube | pipe of the heat exchanger which concerns on Embodiment 3 of this invention. It is a side view which shows the heat exchanger which concerns on Embodiment 4 of this invention.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing a heat exchanger according to Embodiment 1 of the present invention.
FIG. 2 is a side view showing the heat exchanger according to Embodiment 1 of the present invention.
3 is a cross-sectional view taken along the line AA in FIG.
FIG. 4 is an enlarged view showing a portion B of FIG.
As shown in FIGS. 1 to 4, the heat exchanger includes a plurality of fins 1 and a pair of headers (an inlet side header 2 and an outlet side header 3).
The plurality of fins 1 are arranged at intervals, and a fluid (for example, air) flows between them. In the plurality of fins 1, one or a plurality of flow paths 11 through which a medium (for example, a refrigerant) flows are formed.
A pair of headers (inlet side header 2 and outlet side header 3) connect both ends of the plurality of fins 1, respectively. For example, the refrigerant flows from the refrigerant inlet 4 of the inlet header 2. The refrigerant that has flowed into the inlet header 2 flows into the outlet header 3 through the plurality of fins 1. Then, the refrigerant flows out from the refrigerant outlet 5 of the outlet side header 3. In addition, the distribution direction of a refrigerant | coolant is not limited to this, A reverse direction may be sufficient.
With such a configuration, the heat exchanger exchanges heat between the air passing between the plurality of fins 1 and the refrigerant flowing through the flow paths 11 inside the plurality of fins 1.

Further, the plurality of fins 1 satisfy the relationship of 3 ≦ Fp / Ft ≦ 21, where Fp is the pitch between adjacent fins 1 and Ft is the thickness of the fins 1.

FIG. 5 is a diagram showing the performance characteristics of the heat exchanger according to Embodiment 1 of the present invention.
In FIG. 5, the ratio (AK / ΔP) of the heat transfer performance AK [W / K] to the air side ventilation resistance ΔP of the heat exchanger and the thickness of the fin 1 with the conventional heat exchanger as a reference (100%) The relationship with the ratio (Fp / Ft) of fin pitch Fp with respect to Ft is shown.
Here, the AK value is a value obtained by multiplying the heat transfer rate K and the heat transfer area A in the heat exchanger, and represents the heat transfer characteristics of the heat exchanger.
In addition, the conventional heat exchanger used as a reference | standard is a plate fin type heat exchanger which performs heat exchange with the air which passes between several radiation fins, and the refrigerant | coolant which distribute | circulates several heat exchanger tubes. Further, the heat transfer tubes of the conventional heat exchanger are arranged in two rows in the air flow direction, and are arranged in a plurality of stages in a direction orthogonal to the air flow. Further, a circular pipe having a diameter of Φ7.94 mm is used as the heat transfer tube, and the fin pitch Fp = 1.6 mm, the step pitch Dp = 20.4 mm of the heat transfer tube, and the row pitch Lp of the heat transfer tube = 17.7 mm.

As shown in FIG. 5, AK / ΔP decreases when Fp / Ft becomes too small. Further, AK / ΔP decreases when Fp / Ft becomes too large. That is, Fp / Ft has an appropriate range in which AK / ΔP can be improved.
For example, in the case of the same fin pitch Fp, when the thickness Ft of the fin 1 is increased, the flow area of the flow path 11 is increased, the heat transfer rate K is increased due to an increase in the flow velocity of the refrigerant, and the heat transfer performance AK is increased. ΔP increases. However, if the thickness Ft of the fin 1 becomes too thick, the air-side ventilation resistance ΔP increases and AK / ΔP decreases.
Further, for example, when the thickness Ft of the fin 1 is reduced, the air-side ventilation resistance ΔP is reduced and AK / ΔP is increased. However, if the thickness Ft of the fin 1 becomes too thin, the flow path area of the flow path 11 decreases, the heat flow rate K decreases due to a decrease in the flow rate of the refrigerant, the heat transfer performance AK decreases, and AK / ΔP is reduced. descend.

From the above, the heat exchanger according to the first embodiment is 3 ≦ Fp / Ft ≦ so that the value (100%) or more can be improved as compared with the conventional heat exchanger. 21 relationships are satisfied.
Thereby, the heat exchange performance of a heat exchanger can be improved.

Further, in the case of a plate fin type heat exchanger that performs heat exchange between air passing between a plurality of heat radiating fins and a refrigerant flowing through the plurality of heat transfer tubes, as in a conventional heat exchanger, A contact thermal resistance exists between the radiating fins. Moreover, the heat dissipation fin has resistance due to heat conduction.
On the other hand, in the heat exchanger according to the first embodiment, the flow path 11 through which the refrigerant flows is formed inside the fin 1. For this reason, the fin efficiency is approximately 1. Moreover, unlike the conventional heat exchanger, contact thermal resistance between the radiation fin and the heat transfer tube does not occur. Therefore, compared with the conventional heat exchanger, fin efficiency can be improved and the heat exchange performance of a heat exchanger can be improved.

Next, the case where the heat exchanger is applied to a refrigerant circuit of an air conditioner will be described.

FIG. 6 is a refrigerant circuit diagram of the air conditioner according to Embodiment 1 of the present invention.
The refrigerant circuit shown in FIG. 6 includes a compressor 33, a condenser 34, a throttling device 35, and an evaporator 36. The air conditioner includes a blower 37 that blows air to the condenser 34 and the evaporator 36, and a blower motor 38 that drives the blower 37.
By using the heat exchanger in the condenser 34 or the evaporator 36 or both, an air conditioner with high energy efficiency can be realized.
Here, energy efficiency is constituted by the following equation.
Heating energy efficiency = indoor heat exchanger (condenser) capacity / total input Cooling energy efficiency = indoor heat exchanger (evaporator) capacity / total input

When using the said heat exchanger for the evaporator 36, a heat exchanger is arrange | positioned so that the longitudinal direction of the several fin 1 may turn into a gravity direction.
Moreover, when using as the evaporator 36, a refrigerant | coolant flows in the inlet side header 2 arrange | positioned below among a pair of headers (inlet side header 2, outlet side header 3). The refrigerant that has flowed into the inlet header 2 passes through the flow paths 11 of the plurality of fins 1 and flows into the outlet header 3 disposed on the upper side.
That is, the refrigerant flowing into the inlet header 2 is distributed to the same number of paths (refrigerant paths) as the number of the plurality of fins 1 and flows from the bottom to the top of the plurality of fins 1. Thereafter, the refrigerant flows out from the outlet header 3.

The inlet header 2 corresponds to the “lower header” in the present invention.
The outlet header 3 corresponds to the “header disposed on the upper side” in the present invention.

Here, the refrigerant flowing through the evaporator 36 is in a gas-liquid two-phase state. The gas-liquid two-phase refrigerant may have a plug flow or a slag flow. When the heat exchanger is used for the evaporator 36, the refrigerant flows through the flow paths 11 of the plurality of fins 1 from the bottom to the top. Therefore, in the case of a plug flow or a slag flow, the refrigerant does not stagnate due to bubble buoyancy. It can flow upward.
Thereby, the heat exchange performance of a heat exchanger can be improved.

Further, when the evaporation temperature of the refrigerant flowing through the evaporator 36 is lowered, water vapor in the air may condense on the surfaces of the plurality of fins 1 to generate condensed water (condensed water). When using the said heat exchanger for the evaporator 36, a heat exchanger is arrange | positioned so that the longitudinal direction of the several fin 1 may turn into a gravity direction. For this reason, since the dew condensation water flows down between the plurality of fins 1 parallel to the direction of gravity, the drainage of the dew condensation water can be improved. Further, even during the defrost operation in which the frost that has formed on the evaporator 36 is melted, root ice can be prevented from being stacked on the lower portion of the heat exchanger.

Embodiment 2. FIG.
Hereinafter, the difference between the heat exchanger of the second embodiment and the first embodiment will be described. In addition, the same code | symbol is attached | subjected to the structure same as the said Embodiment 1. FIG.

FIG. 7 is a perspective view showing a heat exchanger according to Embodiment 2 of the present invention.
FIG. 8 is a cross-sectional view showing an arrangement of fins of the heat exchanger according to Embodiment 2 of the present invention.
As shown in FIGS. 7 and 8, the heat exchanger according to the second embodiment is provided in two rows in the fluid (air) flow direction. Further, the plurality of fins 1 on the upstream side and the plurality of fins 1 on the downstream side are arranged so as not to overlap each other in the fluid (air) flow direction. That is, the arrangement of the plurality of fins 1 is staggered.

As a result, the air flow developed between the plurality of fins 1 in the first row can develop a new boundary layer at the leading edge of the plurality of fins 1 in the second row, thereby promoting heat transfer. be able to.

In addition, in this Embodiment 2, although the case where two rows of heat exchangers were provided was demonstrated, this invention is not limited to this, You may provide three or more rows.

Embodiment 3 FIG.
Hereinafter, the difference between the heat exchanger of the third embodiment and the first embodiment will be described. In addition, the same code | symbol is attached | subjected to the structure same as the said Embodiment 1. FIG.

FIG. 9 is a perspective view showing a heat exchanger according to Embodiment 3 of the present invention.
FIG. 10 is a cross-sectional view showing the inlet header of the heat exchanger according to Embodiment 3 of the present invention.
FIG. 11 is a diagram showing an inner tube of a heat exchanger according to Embodiment 3 of the present invention.
As shown in FIGS. 9 to 11, the inlet-side header 2 of the heat exchanger according to the third embodiment includes an outer tube 6 and an inner tube 7 provided inside the outer tube 6.
The outer tube 6 is connected to the ends of the plurality of fins 1. The outer tube 6 is a tube having a rectangular cross section, for example, and is closed at both ends. A pipe constituting the refrigerant inlet 4 through which the refrigerant flows into the inner pipe 7 passes through the side surface of the outer pipe 6.
The inner tube 7 is, for example, a circular tube. The inner pipe 7 is formed with a refrigerant inlet 4 through which refrigerant flows and a plurality of outlets 71 through which the refrigerant flowing in from the inlet flows out into the outer pipe 6. The width of the inner tube 7 is substantially equal to the arrangement range of the plurality of fins 1. The plurality of outlets 71 are formed only on the lower side (lower part in the direction of gravity) of the inner tube 7. The plurality of outlets 71 are arranged substantially evenly in the width direction of the inner tube 7.

With such a configuration, when the heat exchanger is used as the evaporator 36, the liquid phase refrigerant flows from the refrigerant inlet 4 into the inner pipe 7. The liquid-phase refrigerant that has flowed into the inner pipe 7 flows out of each of the plurality of outlets 71 into the outer pipe 6. Thereby, inside the inlet side header 2, the liquid phase refrigerant is agitated, and the liquid phase refrigerant flows evenly into the plurality of fins 1. Therefore, local drying of the refrigerant hardly occurs in a part of the plurality of fins 1, and the heat exchange performance of the heat exchanger can be improved.

Embodiment 4 FIG.
Hereinafter, the difference between the heat exchanger of the fourth embodiment and the first embodiment will be described. In addition, the same code | symbol is attached | subjected to the structure same as the said Embodiment 1. FIG.

FIG. 12 is a side view showing a heat exchanger according to Embodiment 4 of the present invention.
As shown in FIG. 12, two heat exchangers according to the fourth embodiment are provided so as to overlap in the direction of gravity. The flow paths 11 of the plurality of fins 1 have a fluid equivalent diameter (equivalent diameter) of 0.05 to 0.2 mm.

When the heat exchanger is used as the evaporator 36, the rectangular channel having a tube inner diameter of 1 mm or less has a constant or increased heat transfer coefficient in the tube even if the refrigerant flow rate is reduced. This is because when the flow rate of the refrigerant decreases, the liquid phase refrigerant stays and the boiling of the refrigerant easily occurs.
In the heat exchanger of the fourth embodiment, the refrigerant flow rate per one flow path 11 inside the plurality of fins 1 is small, but the number of passes is the same as the number of the plurality of fins 1 and the number of passes is very large. it can. For this reason, a heat transfer rate is a grade which is not different from the inside of the circular pipe used for the conventional heat exchanger.
In this case, the length of the heat transfer section required for the dryness to exceed 1 (the length of the plurality of fins 1) needs to be smaller than that of the conventional heat exchanger.
For this reason, two heat exchangers according to the fourth embodiment are provided so as to overlap in the direction of gravity, thereby ensuring a sufficient heat exchange volume even when the length of the plurality of fins 1 is shortened. be able to. For example, when a heat exchanger is mounted on an outdoor unit of an air conditioner, a sufficient heat exchange volume can be ensured even if the unit height of the outdoor unit is the same as that of the conventional unit.

In addition, you may combine arbitrarily the structure of the heat exchanger of the above-mentioned Embodiment 1-4. Even in such a configuration, the heat exchange efficiency of the heat exchanger can be improved.

It should be noted that the effects of the heat exchanger described in the first to fourth embodiments and the air conditioner using the heat exchanger can be achieved in any refrigerant such as R410A, R32, HFO1234yf, and the like.

Moreover, although the example of air and a refrigerant | coolant was shown as a working fluid, even if it uses other gas, liquid, and gas-liquid mixed fluid, there exists the same effect.

In addition, the same effect can be obtained when the heat exchanger described in the first to fourth embodiments is used in either an indoor unit or an outdoor unit of an air conditioner.

Note that the heat exchanger described in the first to fourth embodiments and the air conditioner using the heat exchanger may be a mineral oil, an alkylbenzene oil system, an ester oil system, an ether oil system, a fluorine oil system, or the like. The effect can be achieved with any refrigeration oil, whether the oil is soluble or not.

The utilization example of the present invention is not limited to the above-described air conditioner, but can be used for a heat pump apparatus that needs to improve heat exchange performance and energy saving performance.

1 fin, 2 inlet side header, 3 outlet side header, 4 refrigerant inlet, 5 refrigerant outlet, 6 outer pipe, 7 inner pipe, 11 flow path, 33 compressor, 34 condenser, 35 throttling device, 36 evaporator, 37 blower, 38 blower motor, 71 outlet.

Claims

A plurality of fins that are arranged at intervals and in which a fluid flows therethrough and in which a flow path through which a medium that exchanges heat with the fluid flows is formed;
A pair of headers respectively connecting both ends of the plurality of fins;
With
The plurality of fins are:
When the fin pitch that is the interval between the adjacent fins is Fp, and the thickness of the fin is Ft,
3 ≦ Fp / Ft ≦ 21
A heat exchanger characterized by satisfying the relationship of
A compressor, a condenser, an expansion means, and a refrigerant circuit that connects the evaporator with piping and circulates the refrigerant;
An air conditioner using the heat exchanger according to claim 1 for at least one of the condenser and the evaporator.
A compressor, a condenser, an expansion means, and a refrigerant circuit that connects the evaporator with piping and circulates the refrigerant;
The heat exchanger according to claim 1 is used for the evaporator,
The heat exchanger is
It is arranged so that the longitudinal direction of the plurality of fins is the direction of gravity,
Of the pair of headers, the refrigerant flows into the header disposed on the lower side, and the refrigerant that has flowed into the header disposed on the lower side passes through the plurality of fins and is disposed on the upper side. An air conditioner, wherein the refrigerant flows into the header and the refrigerant flows out from the header disposed on the upper side.
Of the pair of headers, the header arranged on the lower side is:
An outer tube to which ends of the plurality of fins are connected;
An inner pipe provided inside the outer pipe;
With
The inner tube is
An inlet into which the refrigerant flows;
The air conditioner according to claim 2 or 3, wherein a plurality of outlets for allowing the refrigerant flowing in from the inlet to flow out to the outer pipe are formed.
The air conditioner according to claim 4, wherein the plurality of outlets are formed only on a lower side of the inner pipe.
A plurality of the heat exchangers are provided in the fluid flow direction,
The air conditioning according to any one of claims 2 to 5, wherein the plurality of fins on the upstream side and the plurality of fins on the downstream side are arranged so as not to overlap each other in the fluid flow direction. Machine.
The air conditioner according to any one of claims 2 to 6, wherein a plurality of the heat exchangers are provided in the direction of gravity.