JP2010216766A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner in which a coolant and compressor oil, etc., do not remain in a radiation heat exchanger after stopping the inflow of the coolant to the radiation heat exchanger and a temperature of the radiation heat exchanger is easy to be lowered. <P>SOLUTION: In the air conditioner 1, a three-way valve 41 is switched between a first state for making a high-pressure coolant flowing from a compressor 11 flow to the radiation heat exchanger 14 and a second state for making the high-pressure coolant flowing from the compressor 11 flow to a convection heat exchanger 13 in stead of making it flow to the radiation heat exchanger 14. When the three-way valve 41 is in the first state, the high-pressure coolant flows to both the radiation heat exchanger 14 and the convection heat exchanger 13. The three-way valve is switched to the second state when the temperature of the radiation heat exchanger 14 needs to be lowered. When the three-way valve 41 is in the second state, as the high-pressure coolant is not pushed into the radiation heat exchanger 14, the coolant and the compressor oil, etc., do not remain in the radiation heat exchanger 14, thus easily lowering the temperature of the radiation heat exchanger 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an air conditioner including a refrigerant circuit that performs a vapor compression refrigeration cycle.

  As an air conditioner that performs a heating operation using a high-pressure refrigerant, for example, an air conditioner that causes a high-pressure refrigerant to flow through a radiant heat exchanger is disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 7-55234). In the air conditioner described in Patent Document 1 (Japanese Patent Laid-Open No. 7-55234), a valve that adjusts the flow of high-pressure refrigerant into the radiant heat exchanger during heating operation is disposed on the downstream side of the radiant heat exchanger. When the exchanger temperature reaches an upper limit, the valve closes the flow path to prevent high pressure refrigerant from flowing into the radiant heat exchanger.

  However, in the above configuration, the high-pressure refrigerant is pushed into the radiant heat exchanger due to the pressure of the compressor, and refrigerant, compressor oil, and the like stay in the radiant heat exchanger. For this reason, it is difficult for the refrigerant temperature to decrease, and a state occurs in which the refrigerant temperature does not decrease when the temperature of the radiant heat exchanger is desired to decrease. Further, since the return of oil to the compressor is reduced, the possibility of impairing the reliability of the compressor is increased.

  An object of the present invention is to provide an air conditioner in which refrigerant and compressor oil and the like do not stay in the radiant heat exchanger even after the refrigerant inflow to the radiant heat exchanger is stopped, and the temperature of the radiant heat exchanger is likely to decrease.

  An air conditioner according to a first aspect of the present invention is an air conditioner that includes a refrigerant circuit that performs a vapor compression refrigeration cycle and performs a heating operation using at least a high-pressure refrigerant. The refrigerant circuit has a compressor, a convection heat exchanger, a radiant heat exchanger, and a multi-way valve. The compressor discharges a high-pressure refrigerant. The convection heat exchanger exchanges heat between the high-pressure refrigerant flowing inside and the air convection outside. A radiant heat exchanger heats a predetermined member to the high-pressure refrigerant circulating inside, and generates radiant heat from the predetermined member. The multi-way valve is disposed between the compressor and the radiant heat exchanger. The multi-way valve is switched between a first state in which the high-pressure refrigerant flowing from the compressor flows to the radiant heat exchanger and a second state in which the high-pressure refrigerant flowing from the compressor does not flow to the radiant heat exchanger.

  In the conventional air conditioner, even when the radiant heat exchanger is not used, a state in which the high-pressure refrigerant is pushed into the radiant heat exchanger due to the pressure of the compressor occurs. However, in the air conditioner according to the first invention, since the multi-way valve is switched to a state in which the high-pressure refrigerant does not flow into the radiant heat exchanger, the high-pressure refrigerant is not pushed into the radiant heat exchanger, and the refrigerant and the compressor oil are exchanged by radiant heat. The temperature of the radiant heat exchanger tends to decrease without staying in the vessel.

  The air conditioner according to the second invention is the air conditioner according to the first invention, and when the multi-way valve is in the first state, the high-pressure refrigerant flowing from the compressor flows to the convection heat exchanger and the radiant heat exchanger. Further, when the multi-way valve is in the second state, the high-pressure refrigerant flowing from the compressor flows only to the convection heat exchanger.

  In this air conditioner, a heating operation using both a convection heat exchanger and a radiant heat exchanger, or a heating operation using only a convection heat exchanger is executed. When the temperature of the radiant heat exchanger reaches the upper limit during the heating operation using both the convective heat exchanger and the radiant heat exchanger, the multi-way valve switches to a state in which the high-pressure refrigerant does not flow to the radiant heat exchanger. The heating operation using only the convection heat exchanger is executed. As a result, the temperature drop of the radiant heat exchanger is accelerated, and the air conditioner can return to the heating operation using both the convective heat exchanger and the radiant heat exchanger.

  An air conditioner according to a third invention is the air conditioner according to the first invention, and when the multi-way valve is in the first state, the high-pressure refrigerant flowing from the compressor flows only to the radiant heat exchanger. Further, when the multi-way valve is in the second state, the high-pressure refrigerant flowing from the compressor flows only to the convection heat exchanger.

  In this air conditioner, a heating operation using only a radiant heat exchanger or a heating operation using only a convective heat exchanger is executed. When the temperature of the radiant heat exchanger reaches the upper limit during the heating operation using only the radiant heat exchanger, the multi-way valve is switched to a state in which the high-pressure refrigerant does not flow to the radiant heat exchanger, and the convection heat exchanger The heating operation using only the is performed. As a result, the temperature drop of the radiant heat exchanger is accelerated, and the air conditioner can return to the heating operation using only the radiant heat exchanger.

  An air conditioner according to a fourth aspect of the present invention is the air conditioner according to the first aspect of the present invention, wherein the refrigerant circuit further includes a supercooling heat exchanger that cools the high-pressure refrigerant discharged from the radiant heat exchanger. When the multi-way valve is in the first state, the high-pressure refrigerant flowing from the compressor flows to the radiant heat exchanger and the subcooling heat exchanger. Further, when the multi-way valve is in the second state, the high-pressure refrigerant flowing from the compressor flows only to the convection heat exchanger.

  In this air conditioner, when the temperature of the radiant heat exchanger reaches the upper limit during the heating operation using the radiant heat exchanger, the multi-way valve is switched to a state in which the high-pressure refrigerant does not flow to the radiant heat exchanger, and the convection heat Heating operation using only the exchanger is executed. Since the supercooling heat exchanger is disposed downstream of the radiant heat exchanger, the temperature of the refrigerant staying in the radiant heat exchanger and the supercooling heat exchanger is rapidly reduced. As a result, the temperature drop of the radiant heat exchanger is accelerated, and the air conditioner can return to the heating operation using the radiant heat exchanger again.

  In the air conditioner according to the first aspect of the invention, the state where the high-pressure refrigerant is pushed into the radiant heat exchanger is eliminated, and the refrigerant, compressor oil, and the like do not stay in the radiant heat exchanger, and the temperature of the radiant heat exchanger is likely to decrease.

  In the air conditioner according to any one of the second to fourth inventions, the temperature reduction of the radiant heat exchanger is accelerated, and the heating operation using the radiant heat exchanger can be quickly restored.

The refrigerant circuit diagram of the air conditioner which concerns on one Embodiment of this invention. The disassembled perspective view which shows the internal structure of an indoor unit. The side view of a heat exchanger assembly. Sectional drawing which shows the attachment structure of the panel of a radiant heat exchanger, and a heat exchanger tube. The graph which shows the relationship between the detection temperature of the 2nd temperature sensor in heating operation, and operation | movement of a three-way valve. The refrigerant circuit figure of the air conditioner which concerns on the 1st modification of this embodiment. The refrigerant circuit figure of the air conditioner which concerns on the 2nd modification of this embodiment. Sectional drawing of a radiant heat exchanger which shows the 2nd attachment structure of a panel and a heat exchanger tube. Sectional drawing of a radiant heat exchanger which shows the 3rd attachment structure of a panel and a heat exchanger tube. Sectional drawing of a radiant heat exchanger which shows the 4th attachment structure of a panel and a heat exchanger tube. Sectional drawing of a radiant heat exchanger which shows the 5th attachment structure of a panel and a heat exchanger tube. Sectional drawing of a radiant heat exchanger which shows the 6th attachment structure of a panel and a heat exchanger tube.

  Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are specific examples of the present invention and do not limit the technical scope of the present invention.

<Refrigerant circuit 10 of air conditioner 1>
FIG. 1 is a refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention. In FIG. 1, an air conditioner 1 includes a refrigerant circuit 10 that performs a vapor compression refrigeration cycle in which an indoor unit 2 that is mainly disposed indoors and an outdoor unit 3 that is primarily disposed outdoor are connected by a refrigerant communication pipe. Is formed.

  In the refrigerant circuit 10, a compressor 11, a four-way switching valve 12, a three-way valve 41, a radiant heat exchanger 14, a convection heat exchanger 13, an expansion valve 15, and an outdoor heat exchanger 16 are connected in order. An accumulator 20 is connected between the four-way switching valve 12 and the suction port of the compressor 11.

  The four-way switching valve 12 allows the refrigerant that has come out of the compressor 11 to flow to either the radiant heat exchanger 14 side or the outdoor heat exchanger 16 side. For example, during the heating operation, the control unit causes the four-way switching valve 12 to select the flow path shown by the solid line in FIG. 1 and causes the refrigerant to flow to the radiant heat exchanger 14 side. On the other hand, during the cooling operation, the control unit causes the four-way switching valve 12 to select the flow path indicated by the dotted line in FIG. 1 and causes the refrigerant to flow to the outdoor heat exchanger 16 side.

  The convection heat exchanger 13 is a heat exchanger including a plurality of fins and a plurality of heat transfer tubes orthogonal to the fins, and heat is generated between the refrigerant circulating in the heat transfer tubes and the air convection on the fin surface. Let the exchange take place. In the vicinity of the convective heat exchanger 13, a fan 23 for blowing air to the fin surface is disposed.

  The radiant heat exchanger 14 is a heat exchanger composed of an aluminum plate (hereinafter referred to as a panel) and a heat transfer tube fixed to the panel, and the panel is heated by a high-pressure refrigerant circulating in the heat transfer tube. Generate radiant heat from

  The expansion valve 15 is an electric expansion valve as a decompression mechanism, and is connected between the convection heat exchanger 13 and the outdoor heat exchanger 16 and depressurizes the refrigerant by narrowing the refrigerant flow path. The outdoor heat exchanger 16 is a heat exchanger including a plurality of fins and a plurality of heat transfer tubes orthogonal to the fins, and heat is generated between the refrigerant circulating in the heat transfer tubes and the air convection on the fin surface. Let the exchange take place. In the vicinity of the outdoor heat exchanger 16, an outdoor fan 33 for blowing air to the fin surface is disposed. The accumulator 20 accumulates excess liquid refrigerant and returns only the gas refrigerant to the compressor 11.

  The three-way valve 41 has a first flow port A, a second flow port B, and a third flow port C, and allows the high-pressure refrigerant flowing from the compressor 11 to flow to either the radiant heat exchanger 14 or the bypass pipe 50. . For convenience of explanation, a state in which the high-pressure refrigerant discharged from the compressor 11 enters the first circulation port A, exits from the second circulation port B, and faces the radiant heat exchanger 14 is referred to as a first state. Moreover, the state where the high-pressure refrigerant discharged from the compressor 11 enters the first circulation port A, exits from the third circulation port C, and faces the convection heat exchanger 13 is referred to as a second state. The bypass pipe 50 guides the refrigerant from the three-way valve 41 to the pipe 10 a that connects the radiant heat exchanger 14 and the convective heat exchanger 13. That is, the high-pressure refrigerant discharged from the compressor 11 enters the convection heat exchanger 13 from the three-way valve 41 via the radiant heat exchanger 14, and the convection heat exchanger 13 from the three-way valve 41 via the bypass pipe 50. Take one of the routes to enter.

  For convenience of explanation, a junction point between the pipe 10a and the bypass pipe 50 is defined as a point D. A check valve 43 is connected between the point D and the radiant heat exchanger 14. The check valve 43 prevents the refrigerant that has reached point D from entering the radiant heat exchanger 14.

  A discharge temperature sensor 111 is attached to a discharge pipe connecting the discharge port of the compressor 11 and the four-way switching valve 12. The discharge temperature sensor 111 detects the temperature of the high-pressure refrigerant discharged from the compressor 11.

  The control unit controls the temperature of the panel of the radiant heat exchanger 14 based on the temperature detected by the discharge temperature sensor 111. However, if the pipe connecting the three-way valve 41 and the radiant heat exchanger 14 is long and the temperature detected by the discharge temperature sensor 111 differs from the panel temperature due to pressure loss, it is located near the high-pressure refrigerant inlet of the radiant heat exchanger 14. Another temperature sensor (hereinafter referred to as second temperature sensor 114) is attached. In the present embodiment, both the discharge temperature sensor 111 and the second temperature sensor 114 are employed.

<Internal structure of indoor unit 2>
FIG. 2 is an exploded perspective view showing the internal structure of the indoor unit. In FIG. 2, the indoor unit 2 has an outer shell formed by a frame 210 and a grill 240. In the frame 210, a left plate 212 is fixed to the left end of the rectangular opening 211, a right plate 213 is fixed to the right end, and an upper plate 214 is fixed to the upper end. The frame 210 has a fan chamber 210a and an electrical component chamber 210b.

  The grill 240 has an upper outlet 240a, a lower outlet 240b, an opening 240c, a left inlet 240d, and a right inlet 240e. The upper air outlet 240 a is located at the upper part of the grill 240, and the lower air outlet 240 b is located at the lower part of the grill 240. The opening 240c exposes the panel 14a to the indoor space. The left suction port 240 d is located on the left side surface of the grill 240, and the right suction port 240 e is located on the right side surface of the grill 240.

  The air is sucked in from the left suction port 240d and the right suction port 240e by the operation of the fan 23, passes between the heat-insulated back surface of the panel 14a and the suction passage forming plates 115 and 116, and is arranged upstream of the convection heat exchanger 13. Pass through the filtered filter 218. The air that has passed through the filter 218 is guided to the convection heat exchanger 13, exchanges heat with the convection heat exchanger 13, passes through the circular hole 216 a of the bell mouth 216, and enters the fan 23. The air blown out from the fan 23 proceeds into the fan chamber 210a toward the upper blower outlet 240a and the lower blower outlet 240b, and is blown out from the upper blower outlet 240a and the lower blower outlet 240b.

  The circular hole 216 a of the bell mouth 216 is slightly smaller than the inner diameter of the fan 23, and the air that has passed through the circular hole 216 a enters the inside of the fan 23, is pressurized by the vane, and is blown out toward the outer periphery of the fan 23. .

  The motor support plate 215 is fixed between the upper part and the lower part of the fan chamber 210 a and supports the drive motor 23 a of the fan 23. The drive motor 23a is screwed to the motor support plate 215 by screws 23b. Then, the bell mouth 216 closes the fan chamber 210a. The electrical component box 24 is held in the electrical component chamber 210b. In the electrical component box 24, a control unit on which a CPU, a memory, and the like are mounted is accommodated.

  The heat exchanger assembly 220 has a structure in which the convective heat exchanger 13 and the radiant heat exchanger 14 are combined. A drain pan assembly 217 is disposed below the convection heat exchanger 13. For example, when air passes through the convection heat exchanger 13 during cooling operation, moisture contained in the air is condensed on the surface of the convection heat exchanger 13. The drain pan assembly 217 receives condensed water falling from the convection heat exchanger 13.

  A blower outlet assembly 250 is attached to the upper blower outlet 240a. The blower outlet assembly 250 has a louver that changes the blowing direction of air. A left frame 241, a right frame 242, and an upper frame 243 are attached to the left end, the right end, and the upper end of the opening 240c of the grill 240, respectively.

  FIG. 3 is a side view of the heat exchanger assembly. In FIG. 3, in the heat exchanger assembly 220, the convection heat exchanger 13 and the radiant heat exchanger 14 are fixed by a mounting plate 221. The mounting plate 221 is a sheet metal member that extends in a direction opposite to the panel 14a from the frame 14c of the radiant heat exchanger 14, and has a through hole 221a.

  The convective heat exchanger 13 has tube plates 13c in the vicinity of both ends of each heat transfer tube 13b. A screw hole corresponding to the through hole 221a of the mounting plate 221 is formed in the tube plate 13c. The convective heat exchanger 13 and the mounting plate 221 are screwed through the through hole 221a.

  FIG. 4 is a cross-sectional view showing a mounting structure between a panel of a radiant heat exchanger and a heat transfer tube. In FIG. 4, the mounting bracket 14e faces the panel 14a with the heat transfer tube 14b interposed therebetween, and is screwed to the mounting portion 14d fixed to the panel 14a in advance by mounting screws 14f. The attachment portion 14d has a screw hole 14da into which the attachment screw 14f is screwed. The mounting bracket 14e has a flat plate portion 14ea, a raised portion 14eb, and a flange portion 14ec. The flat plate portion 14ea is in close contact with the rear surface of the radiation surface of the panel 14a. The raised portion 14eb is raised from the flat plate portion 14ea, and a U-shaped groove into which the heat transfer tube 14b is fitted is formed. The flange portion 14ec rises from the end of the flat plate portion 14ea and is fixed to the attachment portion 14d. A through hole 14ed corresponding to the screw hole 14da of the mounting portion 14d is formed in the flange portion 14ec.

  After the heat transfer tube 14b is disposed on the back surface of the panel 14a, the through hole 14ed of the mounting bracket 14e is disposed so as to face the screw hole 14da of the mounting portion 14d, and the flange portion 14ec is screwed to the mounting portion 14d by the mounting screw 14f. Stopped. As a result, the mounting bracket 14e and the heat transfer tube 14b are pressed against the panel 14a, and heat transfer from the mounting bracket 14e and the heat transfer tube 14b to the panel 14a is ensured.

<Operation of air conditioner 1>
The air conditioner 1 changes the refrigerant flow path with the four-way switching valve 12 to switch between the cooling operation and the heating operation. First, the case where the refrigerant circuit is a circuit for heating operation will be described.

(Heating operation)
During the heating operation, the four-way switching valve 12 selects the flow path indicated by the solid line in FIG. When the three-way valve 41 is in the first state, the gas refrigerant enters the first circulation port A, exits from the second circulation port B, and enters the heat transfer tube 14b of the radiant heat exchanger 14 (see FIGS. 3 and 4).

  Since the mounting bracket 14e and the heat transfer tube 14b are in close contact with the panel 14a (see FIG. 4), the heat of the gas refrigerant is conducted to the panel 14a through the heat transfer tube 14b, and the temperature of the panel 14a rises. Since the radiant heat is emitted from the panel 14a whose temperature has increased, the air and objects in front of the panel 14a are warmed.

  The gas refrigerant exiting the radiant heat exchanger 14 enters the convection heat exchanger 13 through the check valve 43. The gas refrigerant exchanges heat with the convection air outside the convection heat exchanger 13 and condenses. The air whose temperature has increased in the convection heat exchanger 13 is blown out into the room and warms the room.

  The liquid refrigerant exiting the convection heat exchanger 13 is depressurized by the expansion valve 15 and enters the outdoor heat exchanger 16 on the way to the outdoor heat exchanger 16. The liquid refrigerant exchanges heat with convection air outside the outdoor heat exchanger 16 and evaporates to become a gas refrigerant.

  The gas refrigerant exiting the outdoor heat exchanger 16 returns to the compressor 11 through the four-way switching valve 12 and the accumulator 20. As described above, in the air conditioner 1, the heating operation by the radiant heat exchanger 14 and the convective heat exchanger 13 is performed.

  FIG. 5 is a graph showing the relationship between the temperature detected by the second temperature sensor and the operation of the three-way valve in the heating operation. In FIG. 5, when the temperature detected by the second temperature sensor 114 exceeds a predetermined temperature (70 ° C. in this case), the three-way valve 41 allows the refrigerant flow from the first flow port A to the second flow port B. The refrigerant flow from the first circulation port A to the third circulation port C is switched. That is, the three-way valve 41 switches from a state in which the refrigerant flows to the radiant heat exchanger 14 to a state in which the refrigerant flows only to the convective heat exchanger 14 without flowing to the radiant heat exchanger 14.

  When the preset switching time T1 has elapsed, the three-way valve 41 switches the refrigerant flow from the first flow port A to the second flow port B again, thereby heating by the radiant heat exchanger 14. Operation returns.

(Cooling operation)
Next, the case where the refrigerant circuit is a circuit for cooling operation will be described. During the cooling operation, the flow path indicated by the dotted line in FIG. 1 is selected in the four-way switching valve 12, and the high-pressure gas refrigerant discharged from the compressor 11 goes to the outdoor heat exchanger 16. The gas refrigerant is condensed by exchanging heat with air that convects outside the outdoor heat exchanger 16. The liquid refrigerant from the outdoor heat exchanger 16 is depressurized by the expansion valve 15 and enters the convection heat exchanger 13 on the way to the convection heat exchanger 13. The liquid gas refrigerant evaporates by exchanging heat with the convection air outside the convection heat exchanger 13. The air whose temperature has decreased in the convection heat exchanger 13 is blown out into the room and cools the room.

  The gas refrigerant discharged from the convection heat exchanger 13 passes through the bypass pipe 50 and enters the third circulation port C of the three-way valve 41. The gas refrigerant tends to flow toward the radiant heat exchanger 14 at the point D before entering the bypass pipe 50, but is blocked by the check valve 43. The gas refrigerant that has entered the third flow port C exits from the first flow port A and travels toward the four-way switching valve 12. The gas refrigerant that has exited the four-way switching valve 12 returns to the compressor 11 through the accumulator 20.

<Features>
As described above, in the air conditioner 1, the three-way valve 41 has the first state in which the high-pressure refrigerant flowing from the compressor 11 flows to the radiant heat exchanger 14, and the high-pressure refrigerant flowing from the compressor 11 to the radiant heat exchanger 14. The second state is switched to the convection heat exchanger 13 without flowing into the convection heat exchanger 13. When the three-way valve 41 is in the first state, the high-pressure refrigerant flows through both the radiant heat exchanger 14 and the convective heat exchanger 13. And when it is necessary to lower the temperature of the radiant heat exchanger 14, it is switched to the second state. When the three-way valve 41 is in the second state, since the high-pressure refrigerant is not pushed into the radiant heat exchanger 14, refrigerant, compressor oil and the like do not stay in the radiant heat exchanger 14, and the temperature of the radiant heat exchanger 14 is likely to decrease.

<First Modification>
In the said embodiment, although the radiant heat exchanger 14 and the convective heat exchanger 13 are connected in series, it is not limited to it, The radiant heat exchanger 14 and the convective heat exchanger 13 are connected in parallel. Also good. FIG. 6 is a refrigerant circuit diagram of an air conditioner according to a first modification of the present embodiment. In FIG. 6, when the first flow port A and the second flow port B of the three-way valve 41 are in the first state, the high-pressure gas refrigerant discharged from the compressor 11 flows to the radiant heat exchanger 14. When the first flow port A and the third flow port C of the three-way valve 41 are in the second state, the high-pressure gas refrigerant discharged from the compressor 11 flows to the convection radiant heat exchanger 14.

  In the first modified example, when the temperature of the panel 14a of the radiant heat exchanger 14 reaches the upper limit during the heating operation using only the radiant heat exchanger 14, the three-way valve 41 supplies the high-pressure refrigerant to the radiant heat exchanger 14. It is switched to a state where it does not flow, and the heating operation using only the convection heat exchanger 13 is executed. As a result, the temperature drop of the panel 14a is accelerated, and the air conditioner 1 can return to the heating operation using the radiant heat exchanger 14 at an early stage.

<Second Modification>
FIG. 7 is a refrigerant circuit diagram of an air conditioner according to a second modification of the present embodiment. In FIG. 7, a subcooling heat exchanger 44 is connected to the downstream side of the radiant heat exchanger 14. In the supercooling heat exchanger 44, the internal gas refrigerant is cooled and condensed by blowing air from the fan 23. If the gas refrigerant exiting the radiant heat exchanger 14 is directly condensed with the liquid refrigerant exiting the convection heat exchanger 13 without condensing, a boiling sound is generated and the refrigerant confluence increases. However, since the gas refrigerant exiting the radiant heat exchanger 14 is condensed in the supercooling heat exchanger 44, no boiling sound is generated when it joins with the refrigerant condensed in the convection heat exchanger 13. As a result, the combined noise of the refrigerant is reduced.

  In the second modified example, when the temperature of the panel 14a of the radiant heat exchanger 14 reaches the upper limit during the heating operation using only the radiant heat exchanger 14, the three-way valve 41 causes the high-pressure refrigerant to be transferred to the radiant heat exchanger 14. It is switched to a state where it does not flow, and the heating operation using only the convection heat exchanger 13 is executed. Since the subcooling heat exchanger 44 is arranged on the downstream side of the radiant heat exchanger 14, the temperature drop of the refrigerant staying in the radiant heat exchanger 14 and the supercooling heat exchanger 44 is faster than that in the first modification. As a result, the temperature drop of the panel 14a is accelerated, and the air conditioner 1 can return to the heating operation using the radiant heat exchanger 14 at an early stage.

<Other variations>
The attachment structure of the panel 14a and the heat transfer tube 14b of the radiant heat exchanger 14 is not limited to the form shown in FIG. Hereinafter, another mounting structure will be described with reference to FIGS. For convenience of explanation, the surface opposite to the radiation surface of the panel 14a is referred to as the back surface.

  FIG. 8 is a cross-sectional view of the radiant heat exchanger showing a second mounting structure between the panel and the heat transfer tube. In FIG. 8, the mounting panel 141 has a flat plate portion 141a joined to the back surface of the panel 14a and a raised portion 141b raised from the flat plate portion 141a. The raised portion 141b is raised higher than the diameter of the heat transfer tube 14b, and a U-shaped groove 141c into which the heat transfer tube 14b is fitted is formed. After the heat transfer tube 14b is fitted into the U-shaped groove 141c, crimping is performed so that the open end of the U-shaped groove 141c presses the outer peripheral surface of the heat transfer tube 14b.

  FIG. 9 is a cross-sectional view of the radiant heat exchanger showing a third mounting structure of the panel and the heat transfer tube. In FIG. 9, the panel 14a and the heat transfer tube 14b are joined by brazing. Since the solder 140 spreads around the corner formed at the contact portion between the panel 14a and the heat transfer tube 14b, the thermal conductivity from the heat transfer tube 14b to the panel 14a is high.

  FIG. 10 is a cross-sectional view of a radiant heat exchanger showing a fourth mounting structure of the panel and the heat transfer tube. In FIG. 10, the first mounting bracket 341 has a flat plate portion 341a joined to the back surface of the panel 14a and a raised portion 341b raised from the flat plate portion 341a. The flat plate portion 341a is joined so as to be in close contact with the back surface of the panel 14a by spot welding or brazing welding. The raised portion 341b is raised to a diameter of the heat transfer tube 14b, and a U-shaped groove 341c into which the heat transfer tube 14b is fitted is formed. Further, screw holes 341d are formed on both sides of the U-shaped groove 341c.

  The second mounting bracket 342 has a through hole 342 a corresponding to the screw hole 341 d of the first mounting bracket 341. The second mounting bracket 342 is screwed to the first mounting bracket 341 with a screw 343 so as to cover the heat transfer tube 14b fitted in the U-shaped groove 341c. Since the heat transfer tube 14b slightly protrudes from the U-shaped groove 341c, when the second mounting bracket 342 is screwed to the first mounting bracket 341, the heat transfer tube 14b is compressed and closely contacts the U-shaped groove 341c.

  FIG. 11 is a cross-sectional view of a radiant heat exchanger showing a fifth mounting structure of the panel and the heat transfer tube. In FIG. 11, the presser fitting 441 has a flat plate portion 441a joined to the back surface of the panel 14a and a U-shaped groove 441b that sandwiches the heat transfer tube 14b by the back surface of the panel 14a. After the heat transfer tube 14b is disposed on the back surface of the panel 14a, the U-shaped groove 441b of the presser fitting 441 covers the heat transfer tube 14b. In this state, the flat plate portion 441a and the back surface of the panel 14a are joined by spot welding or brazing welding.

  FIG. 12 is a cross-sectional view of a radiant heat exchanger showing a sixth mounting structure of the panel and the heat transfer tube. In FIG. 12, the panel 14a has a raised portion 541 at a portion corresponding to the arrangement position of the heat transfer tube 14b on the back surface. The raised portion 541 is formed with a U-shaped groove 541 a into which the heat transfer tube 14 b is fitted. The U-shaped groove 541a has such a depth that the outer peripheral surface of the heat transfer tube 14b slightly protrudes when the heat transfer tube 14b is fitted. Screw holes 541b are formed on both sides of the U-shaped groove 541a.

  The presser fitting 542 has a through hole 542 a corresponding to the screw hole 541 b of the raised portion 541. The presser fitting 542 is screwed to the raised portion 541 with a screw 543 so as to cover the outer peripheral surface of the heat transfer tube 14 b slightly protruding from the raised portion 541.

  As mentioned above, according to this invention, it is useful for the heating equipment using a radiant heat exchanger.

DESCRIPTION OF SYMBOLS 1 Air conditioner 10 Refrigerant circuit 11 Compressor 13 Convection heat exchanger 14 Radiation heat exchanger 41 Three-way valve 44 Supercooling heat exchanger

JP-A-7-55234

Claims (4)

An air conditioner comprising a refrigerant circuit (10) for performing a vapor compression refrigeration cycle and performing a heating operation using at least a high-pressure refrigerant,
The refrigerant circuit (10)
A compressor (11) for discharging the high-pressure refrigerant;
A convection heat exchanger (13) for exchanging heat between the high-pressure refrigerant circulating inside and the air convection outside;
A radiant heat exchanger (14) for generating a radiant heat from the predetermined member by heating the predetermined member to the high-pressure refrigerant circulating inside;
A multi-way valve (41) disposed between the compressor (11) and the radiant heat exchanger (14);
Have
The multi-way valve (41) has a first state in which the high-pressure refrigerant flowing from the compressor (11) flows to the radiant heat exchanger (14), and the high-pressure refrigerant flowing from the compressor (11). Switched to the second state not to flow through the radiant heat exchanger (14),
Air conditioner (1). When the multi-way valve (41) is in the first state, the high-pressure refrigerant flowing from the compressor (11) flows to the convection heat exchanger (13) and the radiant heat exchanger (14),
When the multi-way valve (41) is in the second state, the high-pressure refrigerant flowing from the compressor (11) flows only to the convection heat exchanger (13).
The air conditioner (1) according to claim 1. When the multi-way valve (41) is in the first state, the high-pressure refrigerant flowing from the compressor (11) flows only to the radiant heat exchanger (14),
When the multi-way valve (41) is in the second state, the high-pressure refrigerant flowing from the compressor (11) flows only to the convection heat exchanger (13).
The air conditioner according to claim 1. The refrigerant circuit (10) further includes a supercooling heat exchanger (44) for cooling the high-pressure refrigerant that has exited from the radiant heat exchanger (14),
When the multi-way valve (41) is in the first state, the high-pressure refrigerant flowing from the compressor (11) flows to the radiant heat exchanger (14) and the supercooling heat exchanger (44),
When the multi-way valve (41) is in the second state, the high-pressure refrigerant flowing from the compressor (11) flows only to the convection heat exchanger (13).
The air conditioner according to claim 1.

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