JPH0480575A - Refrigerant distributor - Google Patents

Abstract

PURPOSE:To permit the even distribution of refrigerant into heat transfer flow passages in an evaporator or into a plurality of evaporators by a method wherein a choking unit is provided in the refrigerant inlet port side of the evaporator, whose refrigerant flow passage is constituted of a multitude of flow passages, at a position proximate to the inflow port of heat transfer flow passages in the evaporator while the choking unit is formed so that a pressure before the choking unit becomes higher than the saturated pressure of the refrigerant at a refrigerant temperature before an expansion valve provided at the upstream side of the evaporator. CONSTITUTION:A refrigerant distributor 1 is formed so that the pressure of refrigerant at the entrance side of a choking unit 2 becomes higher than the saturated pressure of the refrigerant at a refrigerant temperature at the entrance side of an expansion valve 13. In this case, overcooled refrigerant solution at the entrance side of the expansion valve 13 keeps liquid state still at the entrance side of the refrigerant distributor 1 in an evaporator 14 and becomes two-phase flow of gas and liquid at a place at the outlet side of the choking unit 2. In this system, the space 18 of the entrance side of the refrigerant distributor 1 is filled with the refrigerant solution of the single phase of liquid utilizing the overcooled condition of the refrigerant at the entrance side of the expansion valve 13 while the refrigerant of gas and liquid two-phase, discharged out of respective choking units 2 evenly, is distributed into respective heat transfer tubes 21.

Description

[Detailed description of the invention] (Industrial application field) The present invention is a heat pump equipped with supercooling means.

This relates to a refrigerant distributor applied to refrigerators, etc. (Prior Art) Conventionally, a heat pump equipped with a refrigerant heat exchanger, which is a type of subcooling means, is well known, and is shown in FIG. 7.

This heat pump has a compressor 11, a condenser 12, and an expansion valve 1.
3, an evaporator 14, and a refrigerant heat exchanger 15 that exchanges heat between the refrigerant exiting the condenser 12 and before the expansion valve 13 and the refrigerant exiting the evaporator 14 and before the compressor 11. It has become.

This heat pump uses a refrigerant heat exchanger 15 to
The refrigerant at the outlet of the evaporator 14 is brought into a suitable wet gas or saturated gas state so that the high-pressure liquid refrigerant at the outlet of the condenser 12 is subcooled by evaporation of the refrigerant, and the refrigerant in the evaporator 14 is superheated. In addition to preventing a decrease in the coefficient of performance cop (=evaporation capacity/power) due to heat exchange loss caused by heat exchange, the compressor 11 is appropriately supplied with refrigerant in a superheated gas state to prevent liquid compression in the compressor 11. This is what I did.

Figure 8 shows the state of the refrigerant circulating inside this heat pump.
(Pressure) - i (Enthalpy) The points a, . . . , f in the diagram correspond to the positions indicated by the same symbols in FIG. From FIG. 8, it can be seen that in the case of this apparatus, the refrigerant is supercooled and flows into the evaporator 14 in a gas-liquid two-phase state.

FIG. 9 shows the state inside the evaporator 14 shown in FIG. 8 using an example of a tube type evaporator. A large number of heat transfer tubes 21 forming heat transfer channels are provided, and of the two-phase refrigerant flowing into the header 17 from the refrigerant population 22, the refrigerant liquid is collected in the lower part, and the refrigerant gas G is collected in the upper part.

(Problems to be Solved by the Invention) In the conventional device described above, the refrigerant liquid and refrigerant gas G are separated into upper and lower phases within the header 17, as shown in FIG. For this reason, the refrigerant cannot be distributed evenly to each heat exchanger tube 21 in the evaporator, and the refrigerant gas G is concentrated in the upper heat exchanger tube 21 and the refrigerant liquid is concentrated in the lower heat exchanger tube 21. Since only the refrigerant gas G flows through the heat transfer tubes 21, a problem arises in that the heat transfer coefficient decreases.

Furthermore, even when a plurality of evaporators 14 are installed downstream of the expansion valve 13, it is necessary to distribute the refrigerant equally to each evaporator, but since the refrigerant is a two-phase flow as described above, The problem is that equal distribution is difficult.

The present invention has been made to address the above-mentioned conventional problems, and aims to provide a refrigerant distributor that can evenly distribute refrigerant to a heat transfer channel in an evaporator or to a plurality of evaporators. It is something to do.

(Means for Solving the Problems) In order to solve the above problems, the first invention provides a heat transfer flow path inlet in the evaporator in which the refrigerant flow path is formed of a large number of flow paths and is located in a bulge on the refrigerant inlet side of the evaporator. A constriction part was provided at a position close to the constriction part, and the constriction part was formed so that the pressure in front of the constriction part was higher than the refrigerant saturation pressure with respect to the refrigerant temperature in front of the expansion valve provided upstream of the evaporator.

Further, the second invention provides a constriction section in the vicinity of the evaporator in each refrigerant flow path leading to a plurality of evaporators arranged in parallel, and the pressure in front of the constriction section is adjusted to the pressure in front of the expansion valve provided upstream of the evaporator. The constricted portion was formed so that the pressure was higher than the saturation pressure of the refrigerant relative to the refrigerant temperature.

(Function) By forming as described above, the refrigerant upstream of the constriction part is kept in a single phase, that is, liquid, and the refrigerant is evenly distributed to the heat transfer channel or evaporator downstream of the constriction part. Become so.

(Example) Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an evaporator 14 to which a refrigerant distributor 1 according to a first embodiment of the first invention is applied, which is used in the heat pump shown in FIG. shell 1 with refrigerant population 22 as in the example of FIG.
A large number of heat transfer tubes 21 are arranged in parallel on a partition plate 20 that partitions a heat source water circulation space 19 and a space 18 in the header 17 inside the header 6 . Furthermore, in this embodiment, the refrigerant distributor 1 formed by providing a large number of throttle parts 2 is placed close to the partition plate 20 to form a space 18.
The interior is divided into two parts.

FIG. 2 shows a p-1 diagram in a heat pump system using an evaporator 14 to which this refrigerant distributor 1 is applied,
The symbols in the figure correspond to the positions indicated by the same symbols in FIG. 1, as in the case of FIGS. 7 and 8. The refrigerant distributor 1 is formed so that the pressure in front of the throttle part 2, that is, on the inlet side of the throttle part 2, is higher than the refrigerant saturation pressure with respect to the refrigerant temperature in front of the expansion valve 13, that is, on the inlet side of the expansion valve 13. As shown in FIG. Even on the entrance side of 1,
It remains in a liquid state (state PCI), and becomes a gas-liquid two-phase flow at the point where it exits the constriction section 2 (state PE).

That is, in this system, the space 1 on the inlet side of the refrigerant distributor 1 is
The refrigerant in 8 is made into a single-phase liquid and is filled with refrigerant liquid, so that the two-phase gas-liquid refrigerant uniformly discharged from each throttle section 2 is distributed to each heat transfer tube 21 .

FIG. 3 shows an evaporator 14 to which the refrigerant distributor 1a according to the second embodiment of the first invention is applied, and the refrigerant distributor 1 shown in FIG.
are substantially the same except that a guide plate 3 is provided protruding from each heat exchanger tube 21 side, and corresponding parts are given the same numbers and description thereof will be omitted.

Between the constriction part 2 and the inlet of each heat transfer tube 21, the refrigerant leaving the constriction part 2 does not go straight due to gravity, but is deflected to one side, resulting in uneven distribution. This guide plate 3 is designed to prevent this.

By the way, when the refrigerant flow rate changes due to the pressure 1[11 operation mode or partial load operation of the heat pump system, the pressure difference Δp before and after the refrigerant distributors 1 and 1a changes, and the inlet side of the refrigerant distributors 1 and 1a changes. It is conceivable that it will be difficult to keep the refrigerant always in a single phase of liquid.

Therefore, as shown in FIG. 4, a partition plate 23 is provided to divide the space 18 into several parts (9 in this embodiment), and each space divided by the expansion valve 13, for example, the spaces 18a and 18c on both sides.
The above pressure is controlled by opening and closing the solenoid valves 24 a, 24 b as appropriate depending on the flow rate of the refrigerant. The difference Δp may be maintained and the inlet side of the refrigerant distributor 1 may be formed to always have a single phase.

In addition, in the above embodiment, the refrigerant heat exchanger 1 is used as the subcooling means.
5 has been described, the present invention is not limited to this, but can also be applied to a system using an intercooler, that is, an economizer 26 as a supercooling means, as shown in FIG. It is applicable.

This pump system has a pressure of Mtl'l11. M compressor 12. In a closed loop including the first expansion/contraction type 13a and the evaporator 14, a liquid supercooling economizer 26 includes a second expansion valve 27 and a liquid supercooling section 28 between the condenser I2 and the first expansion valve 13a. It has been established.

Then, the refrigerant in a high-pressure liquid state that has exited the condenser 12 is guided to the economizer 26, where a part of it is branched and a second
The pressure is reduced in the expansion valve 27 to make it into a low-temperature gas state, and the refrigerant is passed through the liquid supercooling section 28, while the remaining part of the refrigerant is passed through the liquid supercooling section 28 through the gas flow from the second expansion valve 27. It is designed to pass through a separate flow path that is isolated from the flow path. During this passing process, heat exchange is performed between the refrigerants in both channels, and the low temperature gas, that is, the flash gas is led to the economizer hole 30 of compressor [11] through the pipe 29, while the high pressure liquid is cooled. , economizer 26
to the first expansion valve 13a.

The economizer hole 30 is formed near the suction side of the compressor 11, and is formed to guide the flash gas into a confined space at an intermediate pressure close to the suction gas pressure.

The other parts are the same as the heat pump system shown in FIG.

Note that the same effect can be obtained by using a flash tank type economizer instead of the liquid supercooling type economizer 26 shown in FIG. 5, or alternatively, the refrigerant may be turned into a supercooled liquid at the expansion valve by an external cooling means. .

FIG. 6 shows an example in which the refrigerant distributor 5 according to the second invention is applied to the heat pump system shown in FIG. 7 when a plurality of evaporators 14, in this example, two evaporators 14 are arranged in parallel. .

In this case, the flow path 6 on the outlet side of the expansion valve 13 is divided into two flow paths 6a and 6b, each of which has one channel 6a.

In the refrigerant distributor 6b, a refrigerant distributor 5 having a constriction part 7 is provided at a position close to the evaporator 14. The pressure on the inlet side of the throttle part 7 is set to be higher than the refrigerant saturation temperature with respect to the refrigerant temperature on the inlet side of the expansion valve 13, and the refrigerant between the expansion valve 13 and each refrigerant distributor 5 is The refrigerant is turned into a liquid state, filled with water, and evenly distributed from each throttle section 7 to each evaporator 4 in a gas-liquid two-phase flow.

In addition, as above, the symbol P in FIG. IPCEI
P1 corresponds to the same symbol in FIG.

Similarly to the first invention, the second invention can also be applied to a heat pump system using an economizer shown in FIG. 5, a flash tank type economizer, or a heat pump system using an external cooling means.

(Effects of the Invention) As is clear from the above description, according to the first invention, the refrigerant flow path is located in the header on the refrigerant inlet side of the evaporator, which is composed of a large number of flow paths, and is connected to the heat transfer flow path inlet in the evaporator. A constriction part is provided at a close position, and the constriction part is formed so that the pressure in front of the constriction part is higher than the refrigerant saturation pressure with respect to the refrigerant temperature in front of the expansion valve provided upstream of the evaporator.

Therefore, it is possible to keep the refrigerant on the inlet side of the refrigerant distributor in a single liquid phase, fill it up, and evenly distribute the refrigerant in a gas-liquid two-phase state to each heat transfer channel from the throttle part. Become.

Further, according to the second invention, a constriction part is provided near the evaporator in each refrigerant flow path leading to a plurality of evaporators arranged in parallel, and the pressure before the constriction part is adjusted to the expansion part provided upstream of the evaporator. The constricted portion is formed so as to be higher than the refrigerant saturation pressure relative to the refrigerant temperature before the valve.

Therefore, by filling the inlet side of the refrigerant distributor with refrigerant liquid as in the case of the first invention, it is possible to equally distribute refrigerant to each evaporator in a two-phase gas-liquid state. play.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of the inlet side of an evaporator of a heat pump system to which a refrigerant distributor according to a first embodiment of the first invention is applied, and FIG. 2 is a p-i diagram showing the state of refrigerant circulating in the heat pump. 3 is a partial sectional view of the inlet side of the evaporator of a heat pump system to which the refrigerant distributor according to the second embodiment of the first invention is applied, and FIG. 4 is a refrigerant diagram showing an example of use of the refrigerant distributor described above. Flow path system diagram, FIG. 5 is an overall configuration diagram of a heat pump system using an economizer, FIG. 6 is a partial sectional view of the inlet side of an evaporator of a heat pump to which the refrigerant distributor according to the second invention is applied, and FIG. 7 Figure 8 shows the overall configuration of a heat pump system using a refrigerant heat exchanger, and Figure 8 shows the state of refrigerant circulating in a heat pump system using a conventional evaporator.
9 is a partial sectional view of the inlet side of the conventional evaporator in the above-mentioned pump system. 1.1a...refrigerant distributor, 2...throttle section, 5...
Refrigerant distributor, 6, 6a, 6b...flow path, 7...throttle section, 14...evaporator, 15...refrigerant heat exchanger, 26
...Economizer. Patent B [People Super Heat Pump Energy Integration System Technology Research Association

Claims (2)

[Claims] (1) A constriction part is provided in the header on the refrigerant inlet side of the evaporator, which has a large number of refrigerant flow paths, at a position close to the inlet of the heat transfer flow path in the evaporator, and the pressure in front of the constriction part is adjusted to the evaporator. A refrigerant distributor characterized in that the constricted portion is formed so as to have a refrigerant saturation pressure higher than a refrigerant saturation pressure with respect to a refrigerant temperature in front of an expansion valve provided upstream of the refrigerant distributor. (2) A constriction part is provided near the evaporator in each refrigerant flow path leading to a plurality of parallel evaporators, and the pressure in front of the constriction part corresponds to the refrigerant temperature in front of the expansion valve provided upstream of the evaporator. A refrigerant distributor characterized in that the constricted portion is formed so that the pressure is higher than the refrigerant saturation pressure.