JP2013108673A - Heat pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump in which flow rate distribution to a heat transfer tube by an evaporator can be made uniform.SOLUTION: The heat pump includes a gas-liquid separator 13 provided to a heating medium circulation line 6 between an expansion valve 5 and an evaporator 2 so as to separate a heating medium passed through the expansion valve 5 into a gas phase and a liquid phase and supply only the heating medium in the liquid phase to the evaporator 2, a gas bypass line 14 configured with one end connected to the gas-liquid separator 13 and the other end connected to the heating medium circulation line 6 between the evaporator 2 and a compressor 3 so as to bypass the heating medium in the gas phase separated by the gas-liquid separator 13 to an exit side of the evaporator 2, and an expansion mechanism 15 provided in an entrance heat transfer header 10 of the evaporator 2 so as to expand the heating medium just before each entrance of a plurality of heat transfer tubes 9.

Description

  The present invention relates to a heat pump.

  Heat exchange of the heat medium with a high-temperature heat source, an evaporator for evaporating the heat medium, a compressor for compressing the heat medium evaporated by the evaporator, and heat exchange of the heat medium compressed by the compressor with a low-temperature heat source, There is known a heat pump including a condenser that condenses a heat medium, and an expansion valve that expands the heat medium condensed by the condenser and supplies the heat medium to an evaporator.

  As an evaporator used for this heat pump, there is an in-pipe evaporation type shell and tube heat exchanger. This evaporator accommodates a plurality of heat transfer tubes in a shell, and is configured by connecting both ends of the plurality of heat transfer tubes to an inlet heat transfer tube header and an outlet heat transfer tube header, respectively, and a heat medium flowing through the plurality of heat transfer tubes Is heated and evaporated by a high-temperature heat source flowing in the shell.

  By the way, in this evaporator, when a heat medium with a large amount of gas phase components is supplied to the evaporator, the flow rate distribution (flow distribution) to each heat transfer tube becomes non-uniform, and the efficiency of the evaporator is significantly deteriorated. There's a problem.

  Specifically, for example, in a horizontal evaporator in which the tube axis direction of the heat transfer tube is horizontal, the heat transfer tube disposed below has a large liquid phase component (becomes liquid rich), so heat transfer characteristics by evaporation Because the heat quantity that can evaporate completely inside the heat transfer tube cannot be exchanged, the quality (dryness, void ratio) near the heat transfer tube inlet does not increase so much, so the volume expansion becomes smaller and the behavior is relatively stable. Show. On the other hand, the heat transfer tube disposed above has a large amount of gas phase components (becomes rich in gas), so the heat transfer characteristics due to evaporation are poor, and the volumetric flow rate increases, so the pressure loss increases and the flow rate decreases.

  As described above, in a horizontal evaporator, when a heat medium having a large amount of gas phase components is supplied, a difference in specific gravity occurs in the heat medium at the position where the heat transfer tube is arranged vertically, and the flow distribution at the heat transfer tube inlet is uneven. End up. In addition, since the non-uniformity of the flow distribution in the upper and lower heat transfer tubes does not have a stable point that once becomes uniform, it remains unstable forever.

  The same problem occurs in a vertical evaporator in which the tube axis direction of the heat transfer tube is vertical. When a heat medium with a large amount of gas phase components is supplied to the vertical evaporator, the apparent liquid level fluctuates due to bubbles, and the heat transfer tube inlet is repeatedly immersed and released in the heat medium, causing pressure loss. The balance of the flow rate is lost, and the flow rate distribution to each heat transfer tube becomes uneven.

  Patent Document 1 proposes a method of making bubbles finer by a porous fine bubble production device for the gas-liquid two-phase heat medium exiting the expansion valve and making the flow distribution to each heat transfer tube uniform. Has been.

  Patent Document 2 proposes a method in which a gas-liquid separator is provided on the downstream side of the expander, and the liquid-phase heat medium separated by the gas-liquid separator is expanded by an expansion valve and then supplied to the evaporator.

JP 2008-286488 A JP 2011-85284 A

  However, the method of Patent Document 1 has a problem that the flow rate distribution becomes extremely non-uniform unless the gas-liquid density difference and the bubble diameter of the heat medium are appropriate.

  The method of Patent Document 2 can improve the flow rate distribution in each heat transfer tube of the evaporator because the vapor phase component supplied to the evaporator is reduced. However, in the method of Patent Document 2, an expansion valve is provided in front of the evaporator to adjust the pressure, and the liquid phase heat medium after gas-liquid separation is expanded by the expansion valve and then introduced into the evaporator. Therefore, gas phase components are mixed during expansion, and the heat medium supplied to the evaporator is not completely liquid-tight (liquid single phase, quality = 0). Therefore, further improvement is desired from the viewpoint of uniform flow distribution.

  This invention is made | formed in view of the said situation, and it aims at providing the heat pump which can make uniform the flow distribution to the heat exchanger tube in an evaporator.

  The present invention was devised to achieve the above object, and a plurality of heat transfer tubes are accommodated in a shell, and both ends of the plurality of heat transfer tubes are respectively connected to an inlet heat transfer tube header and an outlet heat transfer tube header. An evaporator configured to heat and evaporate a heat medium flowing through the plurality of heat transfer tubes by a high-temperature heat source flowing in the shell, a compressor that compresses the heat medium evaporated by the evaporator, and the compressor A heat exchanger that exchanges heat with the low temperature heat source to condense the heat medium, an expansion valve that expands the heat medium condensed by the condenser and supplies the heat medium to the evaporator, and the evaporator In a heat pump comprising a heat medium circulation line that sequentially connects the compressor, the condenser, and the expansion valve in a loop shape, the heat pump is provided in the heat medium circulation line between the expansion valve and the evaporator, Heat medium that has passed through the expansion valve A gas-liquid separator that separates into a gas phase and a liquid phase and supplies only the liquid-phase heat medium to the evaporator, and one end connected to the gas-liquid separator, and between the evaporator and the compressor A gas bypass line that has the other end connected to the heat medium circulation line and bypasses the vapor phase heat medium separated by the gas-liquid separator to the outlet side of the evaporator, and the inlet heat transfer tube of the evaporator An expansion mechanism that is provided in the header and expands the heat medium immediately before the inlets of the plurality of heat transfer tubes.

  The gas bypass line may be provided with a pressure loss adjusting valve for applying a pressure loss equivalent to the pressure loss applied by the expansion mechanism to the gas phase heat medium passing through the gas bypass line.

  The inlet heat transfer tube header is provided so as to be adjacent to the shell with a tube plate interposed therebetween, and the expansion mechanism collectively places openings of the heat transfer tubes on the inner wall of the tube plate on the inlet heat transfer tube header side. And an orifice plate in which orifice holes through which the heat medium passes are formed at positions corresponding to the openings of the heat transfer tubes.

  Each of the heat transfer tubes is fixed so that an end thereof penetrates the tube plate and protrudes into the inlet heat transfer tube header, and the expansion mechanism is sandwiched between the tube plate and the orifice plate. A spacer plate formed thicker than the length of the projecting portion of the heat transfer tube and having a through-hole having a diameter larger than the outer diameter of the heat transfer tube at a position corresponding to the opening of each heat transfer tube. Also good.

  The inlet heat transfer tube header is provided so as to be adjacent to the shell across a tube plate, and the inlet heat transfer tube is provided on the shell side of the tube plate or on the inlet heat transfer tube header side by a high-temperature heat source flowing in the shell. You may provide the heat insulation member which suppresses that the heat medium in a header is heated.

  The gas-liquid separator may be disposed vertically above the evaporator.

  According to the present invention, the flow distribution to the heat transfer tubes in the evaporator can be made uniform.

It is a schematic block diagram of the heat pump which concerns on one embodiment of this invention. FIG. 2 is a Ph diagram of the heat pump of FIG. 1. It is a figure which shows the expansion mechanism used for the heat pump of FIG. 1, (a) is the front view seen from the inlet heat exchanger tube header side, (b) is an expanded longitudinal cross-sectional view. (A), (b) is sectional drawing which shows the modification of the evaporator used by this invention.

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

  FIG. 1 is a schematic configuration diagram of a heat pump according to the present embodiment.

  As shown in FIG. 1, a heat pump 1 includes a heat exchanger that exchanges heat with a high-temperature heat source, an evaporator 2 that evaporates the heat medium, a compressor 3 that compresses the heat medium evaporated by the evaporator 2, and a compressor The heat medium compressed in 3 is heat-exchanged with a low-temperature heat source, the condenser 4 that condenses the heat medium, the expansion valve 5 that expands the heat medium condensed in the condenser 4 and supplies the heat medium to the evaporator 2, and evaporation And a heat medium circulation line 6 that sequentially connects the compressor 2, the compressor 3, the condenser 4, and the expansion valve 5 in a loop shape.

  The evaporator 2 is configured by housing a plurality of heat transfer tubes 9 in a shell 8 and connecting both ends of the plurality of heat transfer tubes 9 to an inlet heat transfer tube header 10 and an outlet heat transfer tube header 11, respectively. A heat medium flowing through 9 is heated and evaporated by a high-temperature heat source flowing in the shell 8, that is, an in-pipe evaporation type shell-and-tube heat exchanger is used. The inlet heat transfer tube header 10 and the outlet heat transfer tube header 11 are provided so as to be adjacent to the shell 8 with the tube plate 12 interposed therebetween, and the header 8 is sandwiched between the headers 10 and 11.

  In the present embodiment, the case of using the horizontal evaporator 2 that is arranged so that the tube axis direction of the heat transfer tube 9 is horizontal will be described. However, the vertical direction that the tube axis direction of the heat transfer tube 9 is arranged vertically is described. A slanted type or a slanted type arranged such that the tube axis direction of the heat transfer tube 9 is inclined with respect to the horizontal direction (or the vertical direction) may be used.

  The heat medium circulation line 6 between the condenser 4 and the expansion valve 5 is provided with an intermediate liquid reservoir 7 for temporarily storing the liquid phase heat medium condensed by the condenser 4.

  A gas-liquid separator 13 is provided in the heat medium circulation line 6 between the expansion valve 5 and the evaporator 2. The gas-liquid separator 13 separates the heat medium that has passed through the expansion valve 5 into a gas phase and a liquid phase, and supplies only the liquid phase heat medium to the evaporator 2.

  The gas-liquid separator 13 is preferably provided directly connected to the downstream side of the expansion valve 5. Normally, the pipe downstream of the expansion valve 5 has a larger diameter than the other pipes, but by connecting the gas-liquid separator 13 directly to the downstream side of the expansion valve 5, the pipe having a large diameter as described above is used. Piping is unnecessary, the configuration is simplified, the number of parts can be reduced, and the cost can be reduced. In addition, the pipe on the inlet side of the gas-liquid separator 13 is a stand-up pipe (so that the tube axis direction is vertical) so that the expanded heat-medium mixed gas medium can be smoothly introduced into the gas-liquid separator 13. It is preferable to provide the expansion valve 5 in the riser pipe.

  As the gas-liquid separator 13, a separated liquid phase heat medium is extracted from a liquid phase extraction nozzle 13a provided below, and a separated gas phase heat medium is extracted from an upper gas phase extraction port 13b. A vertical gas-liquid separator may be used.

  The gas phase outlet 13 b of the gas-liquid separator 13 is connected to the heat medium circulation line 6 between the evaporator 2 and the compressor 3 via the gas bypass line 14 and separated by the gas-liquid separator 13. The heat medium is configured to be bypassed to the outlet side of the evaporator 2.

  The heat pump 1 according to the present embodiment includes an expansion mechanism 15 that is provided in the inlet heat transfer tube header 10 of the evaporator 2 and expands the heat medium immediately before the plurality of heat transfer tubes 9.

  The expansion mechanism 15 functions to adjust the pressure of the heat medium and to impart a pressure loss higher than that of the liquid head in order to eliminate uneven flow distribution due to the liquid head difference between the upper and lower positions of the heat transfer tube 9. The liquid head refers to the water head pressure of the heat medium. Details of the expansion mechanism 15 will be described later.

  By providing the expansion mechanism 15 immediately before the inlet of the heat transfer tube 9, the heat medium is kept in a liquid single phase immediately before the heat transfer tube 9, that is, immediately before the heat medium is distributed. It is possible to eliminate the difference and make the flow distribution to each heat transfer tube 9 uniform.

  However, since pressure loss is imparted by the expansion mechanism 15, the pressure of the heat medium at the outlet of the evaporator 2 becomes smaller than the pressure of the heat medium at the gas phase outlet 13b of the gas-liquid separator 13, As a result, the heat medium hardly flows from the evaporator 2 side to the compressor 3. Therefore, in the present embodiment, the gas bypass line 14 is provided with a pressure loss adjusting valve 16 for applying a pressure loss equivalent to the pressure loss applied by the expansion mechanism 15 to the gas phase heat medium passing through the gas bypass line 14. ing. Although FIG. 1 shows the case where the pressure loss adjusting valve 16 is directly connected to the gas phase extraction port 13b of the gas-liquid separator 13, it may not be directly connected.

  Further, in the present embodiment, the gas-liquid separator 13 is arranged vertically above the evaporator 2 (at least above the inlet heat transfer tube header 10 when the vertical evaporator 2 is used). Thereby, the liquid head of the liquid phase heat medium supplied to the evaporator 2 is enlarged (that is, the pressure is increased) to increase the degree of supercooling, and the heat medium in the inlet heat transfer tube header 10 is in a liquid single phase state. Can be easily maintained.

  Here, a Ph diagram (Mollier diagram) of the heat pump 1 will be described with reference to FIG. In addition, each point of ah in FIG. 2 respond | corresponds to the pressure P and specific enthalpy h of the heat medium in each site | part of ah shown by the enclosing character in FIG.

  As shown in FIGS. 1 and 2, the heat medium (point a) condensed in the condenser 4 to become a liquid phase is decompressed by the expansion valve 5 and introduced into the gas-liquid separator 13. When the heat medium is expanded by the expansion valve 5, it enters a gas-liquid mixed state (point b).

  The liquid phase heat medium separated by the gas-liquid separator 13 is introduced into the inlet heat transfer tube header 10 in a liquid single phase (quality = 0) state (point c), and then further depressurized by the expansion mechanism 15. It is introduced into the heat transfer tube 9 (point d). The heat medium introduced into the heat transfer tube 9 is evaporated in the heat transfer tube 9 and introduced into the outlet heat transfer tube header 11 (point e).

  The gas phase heat medium (point f) separated by the gas-liquid separator 13 is depressurized by the pressure loss adjusting valve 16 and adjusted to substantially the same pressure as the outlet heat transfer pipe header 11, and then from the outlet heat transfer pipe header 11. Merge with heat medium (g point). The combined heat medium is compressed by the compressor 3 (point h), and then condensed by the condenser 4 to become a liquid phase again (point a).

  Next, the expansion mechanism 15 will be described.

  For example, an orifice can be used as the expansion mechanism 15. In this case, the orifice diameter may be appropriately determined in consideration of the flow rate of the heat medium, the liquid head, and the like so as to give a pressure loss that can eliminate the liquid head difference at the upper and lower positions of the heat transfer tube 9.

  When an orifice is used as the expansion mechanism 15, the orifice is individually provided so as to correspond to each of the heat transfer tubes 9, but this is very troublesome and increases the manufacturing cost. Therefore, in the present embodiment, the expansion mechanism 15 is configured by the common orifice plate 21.

  As shown in FIGS. 3A and 3B, the orifice plate 21 is fixed to the inner wall of the tube plate 12 on the inlet heat transfer tube header 10 side so as to cover the openings of the heat transfer tubes 9 together. An orifice hole 22 through which the heat medium passes is formed at a position corresponding to the opening of each heat transfer tube 9 (position at the center of the opening). In FIG. 3A, the casing that covers the inlet heat transfer tube header 10 is omitted.

  In the present embodiment, each heat transfer tube 9 is fixed so that the end portion thereof penetrates the tube plate 12 and protrudes into the inlet heat transfer tube header 10, so that the protrusion of the heat transfer tube 9 interferes. The orifice plate 21 cannot be fixed as it is. Therefore, in order to avoid the interference of the protruding portion of the heat transfer tube 9, a spacer plate 23 is provided.

  The spacer plate 23 is sandwiched between the tube plate 12 and the orifice plate 21 and is formed to be thicker than the length of the protruding portion of the heat transfer tube 9, and the spacer plate 23 is positioned outside the heat transfer tube 9 at a position corresponding to the opening of each heat transfer tube 9. A through hole 24 having a diameter larger than the diameter is formed. When the spacer plate 23 is disposed between the tube plate 12 and the orifice plate 21, the protruding portion of the heat transfer tube 9 is accommodated in the through hole 24 of the spacer plate 23, and the protruding portion of the heat transfer tube 9 interferes with the orifice plate 12. Can be avoided. The spacer plate 23 has a role of avoiding the interference of the protruding portion of the heat transfer tube 9, a role of a seal between the orifice plate 21 and the tube plate 12, and a role of a partition for each heat transfer tube 9.

  In the present embodiment, the projecting portion of the heat transfer tube 9 is welded to the tube plate 12, and a welding mark (welding mark, welding margin) 9 a swelled in a mountain shape is formed around the projecting portion of the heat transfer tube 9. Therefore, in order to avoid this welding mark 9a, the through hole 24 of the spacer plate 23 is formed in a tapered shape whose end on the tube plate 12 side gradually increases in diameter toward the tube plate 12 side. .

  Further, in the present embodiment, the orifice plate 21 and the spacer plate 23 are fixed to the tube plate 12 with bolts (stud bolts) 25 so that they can be attached to and detached from the tube plate 12. Thereby, for example, it is possible to easily cope with changing the orifice diameter of the orifice plate 21. In addition, when changing the orifice plate 21, since the spacer plate 23 can be used in common, there is little waste.

  The orifice plate 21 and the spacer plate 23 are formed with a plurality of bolt holes 26 through which the bolts 25 are passed when being fixed to the tube plate 12. In the present embodiment, bolt holes 26 are formed at appropriate intervals in the peripheral portions of the orifice plate 21 and the spacer plate 23.

  However, when only the peripheral portions of the orifice plate 21 and the spacer plate 23 are bolted, there is a possibility that the center portion of the orifice plate 21 and the spacer plate 23 may float. Therefore, in the present embodiment, several fixing spaces 27 (six locations in FIG. 3A) in which the heat transfer tubes 9 do not exist are provided in the central portion of the tube plate 12, and the orifice plate 21 and the spacer plate 23 are fixed. A bolt hole 26 is formed at a position corresponding to the working space 27, and the peripheral edge portion and the central portion of the orifice plate 21 and the spacer plate 23 are bolted to the tube plate 12, and the tube plate 12, the spacer plate 23, the orifice plate 21 was adhered closely.

  In FIG. 3 (a), the orifice plate 21 and the spacer plate 23 are formed in a substantially oval shape in which upper and lower parts of a disk-shaped member are cut in parallel (two parallel straight line ends are connected by arcs, respectively. And the spacer plate 23 is smaller than the orifice plate 21 (ie, the outer shape of the orifice plate 21 is smaller than the outer shape of the spacer plate 23). Although shown, this is for the sake of convenience that the tube plate 12, the spacer plate 23, and the orifice plate 21 are gradually made smaller in the overlapping order, which is more stable and easier to install. The orifice plate 21 and the spacer plate The shape of 23 is not limited to this. For example, the orifice plate 21 and the spacer plate 23 may have the same shape. The material of the orifice plate 21 and the spacer plate 23 is not particularly limited. For example, SS400, which is a general carbon steel, can be used.

  By using the orifice plate 21 and the spacer plate 23, the expansion mechanism 15 can be easily realized and the workability can be improved even when the number of the heat transfer tubes 9 is very large. Further, even when the outer diameters of the heat transfer tubes 9 are different, if the outer diameter is smaller than the diameter of the through hole 24 of the spacer plate 23 and the arrangement of the heat transfer tubes 9 is the same, the common orifice plate 21, A spacer plate 23 can be used.

  In the present embodiment, the orifice plate 21 and the spacer plate 23 are separated from each other, but the orifice plate 21 and the spacer plate 23 may be integrally formed. However, in this case, it is necessary to perform a technically difficult process of making a hole in one plate material halfway, resulting in an increase in manufacturing cost. As in the present embodiment, the orifice plate 21 and the spacer plate 23 are formed as separate bodies, and these are stacked and fixed to the tube plate 12, thereby realizing the expansion mechanism 15 easily and at low cost. It is possible.

  The operation of the present embodiment will be described.

  In the heat pump 1 according to the present embodiment, the heat medium that is provided in the heat medium circulation line 6 between the expansion valve 5 and the evaporator 2, separates the heat medium that has passed through the expansion valve 5 into a gas phase and a liquid phase. One end is connected to the gas-liquid separator 13 for supplying only the heat medium to the evaporator 2 and the gas-liquid separator 13, and the other end is connected to the heat medium circulation line 6 between the evaporator 2 and the compressor 3. A gas bypass line 14 for bypassing the gas phase heat medium separated by the gas-liquid separator 13 to the outlet side of the evaporator 2, and an inlet heat transfer pipe header 10 of the evaporator 2, and a plurality of heat transfer pipes 9. And an expansion mechanism 15 that expands the heat medium immediately before the entrance of.

  In other words, in the heat pump 1 according to the present embodiment, the gas-liquid separator 13 is provided between the expansion valve 5 and the evaporator 2, and only the liquid single-phase heat medium is removed from the gas-liquid separator 13. The expansion mechanism 15 is provided immediately before the heat transfer tube 9 in the evaporator 2.

  In the above-mentioned Patent Document 2, since the heat medium is gas-liquid separated and then expanded by an expansion valve and then introduced into the evaporator, a heat medium mixed with a gas phase is introduced into the evaporator, and each transfer in the evaporator is performed. The flow distribution to the heat pipes could not be made sufficiently uniform. When an expansion mechanism is provided outside the evaporator as in Patent Document 2, a heat medium mixed with a gas phase is always supplied to the evaporator, and the flow rate distribution to each heat transfer tube in the evaporator is small. It becomes non-uniform.

  On the other hand, in the heat pump 1 of the present invention, the expansion mechanism 15 is provided inside the evaporator 2 and the heat medium is expanded immediately before the inlet of the heat transfer tube 9. The liquid single-phase heat medium is always supplied until immediately before the medium is distributed, and as a result, the flow distribution to the heat transfer tubes 9 in the evaporator 2 can be made uniform.

  In addition, the expansion mechanism 15 provided immediately before the inlet of the heat transfer tube 9 serves to eliminate the header difference between the upper and lower positions of the heat transfer tube 9 by applying pressure loss. The effect of uniformizing is great.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

  For example, in the above embodiment, an orifice (orifice plate 21) is used as the expansion mechanism 15. However, the expansion mechanism 15 is not limited to this, and for example, the diameter of the heat transfer tube 9 itself can be reduced. It is possible to obtain the same effect.

  Moreover, in the said embodiment, although the pipe | tube evaporation type shell and tube type heat exchanger was used as the evaporator 2, it is not restricted to this, For example, this invention is applicable also to a multi-tube radiator type evaporator. .

  Although not mentioned in the above embodiment, the tube plate 12 is heated by a high-temperature heat source flowing in the shell 8, and the heat medium in the vicinity of the tube plate 12 in the inlet heat transfer tube header 10 evaporates into a gas phase. Therefore, there may be a case where the flow rate distribution to each heat transfer tube 9 becomes non-uniform due to the influence of the gas phase heat medium. When heating of the heat medium in the inlet heat transfer tube header 10 by such a high-temperature heat source becomes a problem, as shown in FIGS. 4A and 4B, the shell 8 side of the tube plate 12 or the inlet heat transfer tube header. A heat insulating member 41 that suppresses heating of the heat medium in the inlet heat transfer tube header 10 by a high-temperature heat source flowing in the shell 8 may be provided on the side 10. In FIGS. 4A and 4B, the expansion mechanism 15 is omitted. 4 (a) and 4 (b) show the vertical evaporator 2, it can be applied to a horizontal type or an oblique type.

  Furthermore, if the vicinity of the inlet of the heat transfer tube 9 becomes excessively high, the flow distribution may be uneven due to the influence of the heat medium that has evaporated immediately after flowing into the heat transfer tube 9. It is desirable to provide a heat insulating member 41 so as to cover the end of the heat pipe 9 on the inlet heat transfer pipe header 10 side for a predetermined length, and to suppress excessive heat transfer at the end of the heat transfer pipe 9.

  When the heat insulating member 41 is provided on the inlet heat transfer tube header 10 side, as shown in FIG. 4B, the heat transfer tube 9 protruding from the tube plate 12 has a longer protrusion length, and the longer heat transfer tube 9 protrudes. What is necessary is just to provide the heat insulation member 41 so that a part may be covered. For example, in the vertical evaporator 2, the apparent liquid level inside the inlet heat transfer tube header 10 and the heat transfer tube 9 is normally assumed to be slightly lower than the tube plate 12. By providing the heat insulating member 41 on the header 10 side, the liquid level is raised to the inside of the heat transfer tube 9, and the heat medium at the inlet of the heat transfer tube 9 is made into a liquid single phase, and the flow distribution can be made uniform.

  The material of the heat insulating member 41 is not particularly limited. For example, Teflon resin (Teflon is a registered trademark) can be used. It is desirable that the thickness of the heat insulating member 41 is about 30 mm at most, and the length does not affect the effective length of the heat transfer tube 9.

  Of course, one or both of the orifice plate 21 and the spacer plate 23 may be made of a heat insulating material so as to have a function as the heat insulating member 41.

1 Heat Pump 2 Evaporator 3 Compressor 4 Condenser 5 Expansion Valve 6 Heat Medium Circulation Line 8 Shell 9 Heat Transfer Tube 10 Inlet Heat Transfer Tube Header 11 Outlet Heat Transfer Tube Header 12 Tube Plate 13 Gas-Liquid Separator 14 Gas Bypass Line 15 Expansion Mechanism 16 Pressure loss adjustment valve

Claims (6)

A plurality of heat transfer tubes are housed in a shell, and both ends of the plurality of heat transfer tubes are connected to an inlet heat transfer tube header and an outlet heat transfer tube header, respectively, and a heat medium flowing through the plurality of heat transfer tubes is formed in the shell. An evaporator that heats and evaporates by a high-temperature heat source flowing through the compressor, a compressor that compresses the heat medium evaporated by the evaporator, heat-exchanges the heat medium compressed by the compressor with a low-temperature heat source, and A condenser for condensing, an expansion valve for expanding the heat medium condensed in the condenser and supplying it to the evaporator, the evaporator, the compressor, the condenser, and the expansion valve are sequentially looped. In a heat pump having a heat medium circulation line to be connected,
Provided in the heat medium circulation line between the expansion valve and the evaporator, the heat medium that has passed through the expansion valve is separated into a gas phase and a liquid phase, and only the liquid phase heat medium is supplied to the evaporator A gas-liquid separator;
One end is connected to the gas-liquid separator, the other end is connected to the heat medium circulation line between the evaporator and the compressor, and the gas phase heat medium separated by the gas-liquid separator is A gas bypass line to bypass to the outlet side of the evaporator;
An expansion mechanism that is provided in the inlet heat transfer tube header of the evaporator and expands a heat medium immediately before the inlets of the plurality of heat transfer tubes;
A heat pump comprising: The heat pump according to claim 1, wherein the gas bypass line is provided with a pressure loss adjusting valve for applying a pressure loss equivalent to the pressure loss applied by the expansion mechanism to a gas phase heat medium passing through the gas bypass line. The inlet heat transfer tube header is provided adjacent to the shell across a tube sheet,
The expansion mechanism is fixed to the inner wall of the tube plate on the inlet heat transfer tube header side so as to collectively cover the openings of the heat transfer tubes, and the expansion mechanism is located at positions corresponding to the openings of the heat transfer tubes. The heat pump according to claim 1, further comprising an orifice plate having an orifice hole through which a heat medium passes. Each of the heat transfer tubes is fixed so that an end thereof penetrates the tube plate and protrudes into the inlet heat transfer tube header,
The expansion mechanism is sandwiched between the tube plate and the orifice plate, is formed to be thicker than the length of the projecting portion of the heat transfer tube, and is located outside the heat transfer tube at a position corresponding to the opening of each heat transfer tube. The heat pump according to claim 3, further comprising a spacer plate in which a through hole having a diameter larger than the diameter is formed. The inlet heat transfer tube header is provided adjacent to the shell across a tube sheet,
The heat insulating member which suppresses that the heat medium in the said inlet heat exchanger tube header is heated by the high temperature heat source which flows in the said shell in the said shell side or the said inlet heat exchanger tube header side of the said tube sheet was provided. 4. The heat pump according to any one of 4. The heat pump according to any one of claims 1 to 5, wherein the gas-liquid separator is disposed vertically above the evaporator.