JP2006084135A - Heat radiating system and stirling refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat radiating system and a Stirling refrigerator for restraining cavitation in a refrigerant pipe. <P>SOLUTION: This heat radiating system has a high temperature side evaporator 3B arranged around a heat radiating part in a Stirling refrigerating machine 2 and evaporating an inside refrigerant, a first circulating circuit 30 including a high temperature side condenser 3 for condensing the refrigerant by receiving the evaporated refrigerant and returning the condensed refrigerant in the high temperature side evaporator 3B, a second circulating circuit 31 including a condensation preventive pipe 32 connected to a lower part of the high temperature side evaporator 3B and a circulating pump 33 installed in the condensation preventive pipe 32 and returning the refrigerant in the high temperature side evaporator 3B by introducing the refrigerant to an external part of the high temperature side evaporator 3B, and a heat radiating fin 34 as a cooling means for cooling the refrigerant flowing between the high temperature side evaporator 3B and the circulating pump 33. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat dissipation system and a Stirling Refrigerator / Freezer, and more particularly, to a heat dissipation system and a Stirling cooler in which the occurrence of cavitation in refrigerant piping is suppressed.

  As what applied the heat exchange by a reverse Stirling cycle to a refrigerator, what was described in Unexamined-Japanese-Patent No. 2003-50073 (conventional example 1) etc. are mentioned, for example.

In Conventional Example 1, the high temperature part for radiating the compression heat of the working gas due to the reverse Stirling cycle to the outside, the low temperature part for absorbing the expansion heat of the working gas due to the reverse Stirling cycle from the outside, and the heat at the low temperature part A low-temperature side circulation circuit composed of a closed circuit in which a low-temperature side condenser and a plurality of low-temperature side evaporators connected to form a thermosiphon are connected to each other, A Stirling refrigeration system is disclosed that is enclosed in a side circulation circuit. Here, the heat in the high temperature part is radiated by the high temperature side heat exchange cycle (heat radiation system). The high temperature side heat exchange cycle includes a high temperature side evaporator and a high temperature side condenser connected by piping, and heat is conveyed and released by the thermosiphon principle.
JP 2003-50073 A

  However, the above heat dissipation system has the following problems.

  In the heat dissipation system, in addition to the thermosiphon circuit described above, a forced circulation circuit that includes a circulation pump and is supplied with a liquefied refrigerant from a high-temperature side evaporator may be formed. The heat of the refrigerant flowing in the forced circulation circuit is used, for example, to prevent dew generation in a refrigerator.

  Here, since the relatively high-temperature liquefied refrigerant is supplied from the high-temperature side evaporator to the piping of the forced circulation circuit, bubbles are likely to be generated in the refrigerant flowing through the piping (the cavitation is likely to occur). ing. When cavitation occurs, there is a problem that noise may be generated or piping may be damaged.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat dissipation system and a Stirling cooler in which cavitation in a refrigerant pipe is suppressed.

  A heat dissipation system according to the present invention includes an evaporator that is provided around a heat source and evaporates an internal refrigerant, and a condenser that accepts the evaporated refrigerant and condenses the refrigerant, and the condensed refrigerant is contained in the evaporator. A first circulation circuit for returning to the evaporator, a refrigerant flow path connected to the lower part of the evaporator, and a circulation pump attached to the refrigerant flow path, guiding the refrigerant to the outside of the evaporator, and returning the refrigerant to the evaporator And a cooling circuit for cooling the refrigerant flowing between the evaporator and the circulation pump.

  By cooling the refrigerant, the refrigerant temperature decreases. As a result, the generation of bubbles (cavitation) is suppressed.

  A piezoelectric pump may be used as the circulation pump.

  When a piezoelectric pump is used, pulsation occurs, so that negative pressure is likely to occur on the upstream side of the pump, and cavitation is likely to occur. The present invention solves the problems peculiar to the piezoelectric pump.

  As said cooling means, what contains the radiation fin provided in the refrigerant | coolant flow path located between an evaporator and a circulation pump can be considered.

  By using the radiation fins, an effective cooling means can be obtained with a simple structure.

  The heat dissipating system may further include a blowing unit installed in the vicinity of the condenser, and the cooling unit may include the blowing unit. Here, it is preferable to arrange a part of the refrigerant flow path located between the evaporator and the circulation pump in the air flow generated by the blowing means.

  Also in this case, an effective cooling means can be obtained with a simple structure. Further, the air blowing means for the condenser is also used as the cooling means, thereby saving space in the warehouse. Here, by arranging a part of the refrigerant flow path located between the evaporator and the circulation pump in the air flow generated by the blowing means, heat exchange by the air flow is promoted.

A temperature T1 of the refrigerant flowing in the refrigerant passage located near the inlet of the circulation pump in the second circulation circuit, a temperature T0 of the refrigerant flowing in the refrigerant passage located near the outlet of the evaporator in the second circulation circuit, and The refrigerant head ANTOINE constants A, B, and C, the position head difference between the vicinity of the outlet of the evaporator in the second circulation circuit and the vicinity of the inlet of the circulation pump in the second circulation circuit, and the flow path area of the refrigerant flow path The pressure difference Pg due to the difference, the pressure loss amount ΔP due to the piping resistance of the refrigerant flow path from the vicinity of the outlet of the evaporator to the vicinity of the inlet of the circulation pump, and bubbles for generating bubbles in the refrigerant flowing in the refrigerant flow path The superheat degree Ts is
T1 ≦ B / (A−log (Pg−ΔP + 10 ^{(AB / (C + T0)} ) − C + Ts)
It is preferable to satisfy the relationship.

  Cavitation is sufficiently suppressed by lowering the refrigerant temperature T1 in the vicinity of the pump inlet to this level.

  The Stirling refrigerator according to the present invention includes a Stirling refrigerator having a low temperature part and a high temperature part as a heat source, and the heat dissipation system described above.

  In the heat dissipation system described above, cavitation in the refrigerant pipe is suppressed. Therefore, a Stirling cooler in which generation of noise and the like is suppressed is provided.

  According to the present invention, cavitation in refrigerant piping can be suppressed.

  Embodiments of a heat dissipation system and a Stirling cooler according to the present invention will be described below with reference to FIGS.

  In the present specification, the “cooling box” is a concept including all of “refrigerator”, “freezer”, and “freezer refrigerator”.

  Further, in the present embodiment, the case where the “heat dissipation system” is applied to a Stirling refrigerator as a typical example of the “Stirling engine” will be described. It is not applied only to the heat radiating part) but can be applied to any heat source. The application of the “Stirling engine” is not limited to the “refrigerator”. For example, the “Stirling engine” can be used as the “generator”.

  FIG. 1 is a diagram showing a Stirling cooler according to one embodiment of the present invention.

  The Stirling refrigerator 1 shown in FIG. 1 includes at least one of a refrigerated space and a refrigerated space as a cooling space. The Stirling refrigerator 2 (Stirling engine) includes a worm head (heat dissipating part) and a cold head (heat absorbing part).

  The Stirling cooler 1 includes a high temperature side heat transfer cycle for cooling the warm head of the Stirling refrigerator 2 and a low temperature side heat transfer cycle for heat exchange between the inside of the cooler and the cold head of the Stirling refrigerator 2. Yes.

  The high temperature side heat transfer cycle is connected to the high temperature side evaporator by a high temperature side evaporator comprising a high temperature side conduit and a high temperature side return pipe, and a high temperature side evaporator mounted in contact with the periphery of the worm head of the Stirling refrigerator 2 The high-temperature side condenser 3 is provided with a circulation circuit.

Water (H ₂ O) or the like is sealed as a refrigerant in the high-temperature side circulation circuit. The refrigerant evaporated in the high temperature side evaporator reaches the high temperature side condenser 3 through the high temperature side conduit. The refrigerant is condensed by heat exchange with the outside air in the high temperature side condenser 3. The condensed refrigerant returns to the high temperature side evaporator via the high temperature side return pipe. Thus, the high temperature side condenser 3 is arranged above the high temperature side evaporator so that the heat generated by the worm head can be transmitted using the natural circulation caused by the evaporation and condensation of the refrigerant. . Further, the pressure in the circulation circuit system is adjusted in order to adjust the boiling point of the refrigerant.

  The low-temperature side heat transfer cycle is a low-temperature side condenser formed by a low-temperature side condenser attached in contact with the periphery of the cold head of the Stirling refrigerator 2 and a low-temperature side refrigerant passage 6 including a low-temperature side conduit and a low-temperature side return pipe. It has a circulation circuit composed of a low temperature side evaporator 5 connected thereto. In FIG. 1, the low temperature side return pipe and the low temperature side pipe separated from each other are collectively shown as a low temperature side refrigerant passage 6.

  Carbon dioxide, hydrocarbons, etc. are sealed as refrigerant in the low-temperature side circulation circuit. The refrigerant condensed in the low temperature side condenser reaches the low temperature side evaporator 5 via the low temperature side conduit. Heat exchange is performed by evaporating the refrigerant in the low temperature side evaporator 5. After heat exchange, the gasified refrigerant returns to the low temperature side condenser via the low temperature side return pipe. Thus, the low temperature side evaporator 5 is arranged below the low temperature side condenser so that the cold heat generated in the cold head can be transmitted using the natural circulation caused by the evaporation and condensation of the refrigerant. . Further, the pressure in the circulation circuit system is adjusted in order to adjust the boiling point of the refrigerant.

  As shown in FIG. 1, the Stirling refrigerator 2 is arranged at the upper part of the back surface of the refrigerator main body 1A. Moreover, a low temperature side heat conveyance cycle is arrange | positioned at the refrigerator main body back surface 1B side, and a high temperature side heat conveyance cycle is arrange | positioned at the upper side of the refrigerator main body 1A. The low-temperature side evaporator 5 is installed in a cool air duct 5A provided on the cooler body back 1B side, and the high-temperature side condenser 3 is installed in a duct 3A provided on the top of the cooler body 1A. .

  When the Stirling refrigerator 2 is operated, the heat generated by the worm head of the refrigerator 2 is heat-exchanged with the air in the duct 3 </ b> A via the high temperature side condenser 3. At this time, warm air in the duct 3A is discharged out of the Stirling cooler 1 by the blower fan 4, and air outside the Stirling cooler 1 is taken in to promote heat exchange.

  On the other hand, the cold generated in the cold head of the Stirling refrigerator 2 is heat-exchanged with the air in the cold air duct 5 </ b> A via the low-temperature side evaporator 5. At this time, the cool air cooled by the low-temperature evaporator 5 is blown into the cooler (cooling space) by the cooler 7 in the cooler. The warmed airflow from the cooling space is sent again to the low temperature side evaporator 5 through the cold air duct 5A and repeatedly cooled.

  With the implementation of the cooling cycle described above, frost is formed in the refrigerator (for example, around the low temperature side evaporator 5). On the other hand, defrosting is performed by appropriately adjusting the flow of the refrigerant. About this defrost method, since a generally well-known technique can be used, detailed description is not performed.

  By performing the defrosting described above, defrosted water is generated. The defrost water is led from the cold air duct 5A through the drain pipe 8 to the drain pan 9 (evaporation dish) installed at the lower part of the bottom surface 1C of the refrigerator main body. A blower fan 10 is provided on the top of the drain pan 9, and an air flow is formed near the surface of the defrost water accumulated in the drain pan 9 by the blow fan 10, and relatively dry air is supplied onto the defrost water. Therefore, evaporation of defrost water is promoted.

  FIG. 2 is a side sectional view showing an example of the structure of the Stirling refrigerator 2.

  As shown in FIG. 2, the Stirling refrigerator 2 of the present embodiment includes a casing 12, a cylinder 13 assembled to the casing 12, a piston 14 and a displacer 15 reciprocating in the cylinder 13, and a regenerator. 16, a working space 17 including a compression space 17A and an expansion space 17B, a heat radiating portion 18 (worm head), a heat absorbing portion 19 (cold head), a linear motor 23 as piston driving means, a piston spring 24, , A displacer spring 25, a displacer rod 26, and a back pressure space 27.

  In the example of FIG. 2, the outer shell (outer wall) of the Stirling refrigerator 2 is not formed of a single container, but is positioned on the casing 12 (vessel portion) located on the back pressure space 27 side and on the working space 17 side. The heat dissipating part 18, the regenerator 16, and the outer wall part of the heat absorbing part 19 are mainly configured. The casing 12 defines a back pressure space 27. Various components including a cylinder 13, a linear motor 23, a piston spring 24, and a displacer spring 25 are assembled to the casing 12. The outer shell is filled with a working medium such as helium gas, hydrogen gas, or nitrogen gas.

  The cylinder 13 has a substantially cylindrical shape, and receives the piston 14 and the displacer 15 in a reciprocating manner. In the cylinder 13, the piston 14 and the displacer 15 are coaxially spaced apart, and the piston 14 and the displacer 15 divide the working space 17 in the cylinder 13 into a compression space 17 </ b> A and an expansion space 17 </ b> B. More specifically, the working space 17 is a space located closer to the displacer 15 than the end face of the piston 14 on the displacer 15 side, and a compression space 17A is formed between the piston 14 and the displacer 15, and the displacer 15 and the heat absorbing portion. An expansion space 17B is formed between The compression space 17 </ b> A is mainly surrounded by the heat radiating portion 18, and the expansion space 17 </ b> B is mainly surrounded by the heat absorbing portion 19.

  Between the compression space 17A and the expansion space 17B, a regenerator 16 in which a film is wound with a predetermined gap on the inner peripheral surface of the tube 18A is disposed. The compression space 17A and the expansion space 17B communicate with each other. Thereby, a closed circuit is formed in the Stirling refrigerator 2. The working medium sealed in the closed circuit flows in accordance with the operations of the piston 14 and the displacer 15, thereby realizing a reverse Stirling cycle.

  A linear motor 23 is disposed in the back pressure space 27 located outside the cylinder 13. The linear motor 23 includes an inner yoke 20, a movable magnet portion 21, and an outer yoke 22, and the piston 14 is driven in the axial direction of the cylinder 13 by the linear motor 23.

  One end of the piston 14 is connected to a piston spring 24 constituted by a leaf spring or the like. The piston spring 24 functions as an elastic force applying means for applying an elastic force to the piston 14. By applying an elastic force to the piston spring 24, the piston 14 can be reciprocated in the cylinder 13 more stably and periodically. One end of the displacer 15 is connected to a displacer spring 25 via a displacer rod 26. The displacer rod 26 is disposed through the piston 14, and the displacer spring 25 is constituted by a leaf spring or the like. The peripheral edge of the displacer spring 25 and the peripheral edge of the piston spring 24 are supported by a support member that extends from the linear motor 23 toward the back pressure space 27 of the piston 14 (hereinafter sometimes referred to as the rear).

  A back pressure space 27 surrounded by the casing 12 is disposed on the opposite side of the piston 14 from the displacer 15. The back pressure space 27 includes an outer peripheral region located around the piston 14 in the casing 12 and a rear region located closer to the piston spring 24 (rear side) than the piston 14 in the casing 12. There is also a working medium in the back pressure space 27.

  A heat exchanger 180 (first heat exchanger) and a heat exchanger 190 (second heat exchanger) are provided on the inner peripheral surfaces of the heat radiating unit 18 and the heat absorbing unit 19, respectively. The heat exchangers 180 and 190 perform heat exchange between the compression space 17 </ b> A and the expansion space 17 </ b> B and the heat radiating unit 18 and the heat absorbing unit 19, respectively.

  Next, the operation of the Stirling refrigerator 2 will be described.

  First, the linear motor 23 is actuated to drive the piston 14. The piston 14 driven by the linear motor 23 approaches the displacer 15 and compresses the working medium (working gas) in the compression space 17A.

  When the piston 14 approaches the displacer 15, the temperature of the working medium in the compression space 17 </ b> A increases, but heat generated in the compression space 17 </ b> A is released to the outside by the heat radiating unit 18. Therefore, the temperature of the working medium in the compression space 17A is maintained almost isothermal. That is, this process corresponds to an isothermal compression process in a reverse Stirling cycle.

  After the piston 14 approaches the displacer 15, the displacer 15 moves to the heat absorbing portion 19 side. On the other hand, the working medium compressed in the compression space 17A by the piston 14 flows into the regenerator 16, and further flows into the expansion space 17B. At that time, the heat of the working medium is stored in the regenerator 16. That is, this process corresponds to an isovolumetric cooling process in a reverse Stirling cycle.

  The high-pressure working medium that has flowed into the expansion space 17B expands when the displacer 15 moves to the piston 14 side (the rear end side of the casing 12). As the displacer 15 moves rearward in this way, the center portion of the displacer spring 25 is also deformed so as to protrude rearward.

  When the working medium expands in the expansion space 17B as described above, the temperature of the working medium in the expansion space 17B decreases, but external heat is transferred to the expansion space 17B by the heat absorbing portion 19, so that The inside of the expansion space 17B is kept almost isothermal. That is, this process corresponds to an isothermal expansion process of a reverse Stirling cycle.

  Thereafter, the displacer 15 starts to move away from the piston 14. Thereby, the working medium in the expansion space 17B passes through the regenerator 16 and returns to the compression space 17A side again. At this time, since the heat stored in the regenerator 16 is applied to the working medium, the working medium is heated. That is, this process corresponds to a constant volume heating process of a reverse Stirling cycle.

  By repeating this series of processes (isothermal compression process-isovolume cooling process-isothermal expansion process-isovolume heating process), an inverse Stirling cycle is configured. As a result, the endothermic part 19 gradually becomes low temperature and has a very low temperature. On the other hand, the heat radiating part 18 gradually becomes high temperature. As described above, the cold heat in the heat absorbing unit 19 is supplied into the refrigerator through the low temperature side heat transfer cycle, and the heat in the heat radiating unit 18 is released to the outside of the refrigerator through the high temperature side heat transfer cycle.

  FIG. 3 is a diagram showing a configuration of a high temperature side refrigerant circuit (heat radiation system) in the Stirling refrigerator 1. The heat dissipation system according to the present embodiment has first and second circulation circuits described later as a basic configuration. FIG. 4 is a diagram showing a second circulation circuit in the heat dissipation system shown in FIG.

  With reference to FIG. 3, the refrigerant in the high temperature side evaporator 3B attached to the heat radiation part of the Stirling refrigerator 2 is divided into a gas phase 3C located above and a liquid phase 3D located below. In the heat dissipation system, as described above, in order to release the heat generated in the heat dissipation section of the Stirling refrigerator 2 to the outside of the refrigerator, a natural circulation circuit including a high temperature side evaporator 3B and a high temperature side condenser 3 ( A first circulation circuit 30) is formed. Further, in this heat radiation system, a forced circulation circuit including a circulation pump 33 and guiding the liquid phase 3D refrigerant to the outside of the evaporator 3B and returning the refrigerant into the evaporator 3B after using the heat of the refrigerant. (Second circulation circuit 31) is formed. The heat of the refrigerant is used, for example, to prevent dew generation. In this case, the forced circulation circuit 31 includes a dew condensation prevention pipe 32 as shown in FIG. As shown in FIG. 4, the dew condensation prevention pipe 32 guides the refrigerant in the high temperature side evaporator 3B from the lower part of the high temperature side evaporator 3B to the outside of the evaporator 3B, and circulates over the entire front surface of the Stirling cooler body 1A. Then, it is returned from the upper part of the high temperature side evaporator 3B into the evaporator 3B. As the circulation pump 33, a piezoelectric pump using a piezoelectric element such as crystal or lithium niobate is used.

  By the way, since the heat of the heat radiation part in the Stirling refrigerator 2 is transmitted to the refrigerant in the high temperature side evaporator 3B, the refrigerant flowing in the dew condensation prevention pipe 32 is relatively high temperature, and the refrigerant is in a state close to a saturated liquid. It is thought that. Therefore, cavitation is also generated by local pressure fluctuations, which may cause noise or damage to the piping. In particular, it is considered that this problem appears remarkably in the refrigerant flowing in the dew prevention pipe 32 from the high temperature side evaporator 3B to the circulation pump 33. In addition, forced circulation by the piezoelectric pump causes pulsation in the flow, so that local pressure fluctuations are likely to occur.

  On the other hand, in the heat dissipation system according to the present embodiment, the heat dissipation fins 34 (cooling means) are attached to the dew condensation prevention pipe 32 positioned between the high temperature side evaporator 3B and the circulation pump 33. Further, the portion where the radiation fins 34 are attached to the dew condensation prevention pipe 32 is piped at a position where an airflow (broken arrow in FIG. 3) generated by the radiation fan 4 that promotes heat exchange between the high temperature side condenser 3 and the outside air reaches. Is done. Thereby, the heat radiating fan 4 can also be used as a cooling means for the refrigerant in the dew prevention pipe 32.

  By cooling the refrigerant in the dew condensation prevention pipe 32 with the above configuration, the generation of bubbles in the external refrigerant can be suppressed. That is, cavitation is suppressed.

  FIG. 5 is a view showing a modification of the configuration of the high-temperature side refrigerant circuit (heat radiation system) in the Stirling refrigerator 1. Moreover, FIG. 6 is a figure which shows the 2nd circulation circuit in the thermal radiation system shown in FIG.

  Referring to FIGS. 5 and 6, also in the present modified example, heat radiation fins 34 (cooling means) are attached to dew prevention pipe 32 located between high temperature side evaporator 3 </ b> B and circulation pump 33. Further, the portion where the heat radiation fins 34 are attached to the dew condensation prevention pipe 32 is the position where the air flow (broken arrows in FIG. 5) generated by the heat radiation fan 4 that promotes heat exchange between the high temperature side condenser 3 and the outside air reaches. Thus, the pipe is provided downstream of the high temperature side condenser 3. By providing a dew prevention pipe 32 downstream of the high temperature side condenser 3, a relatively high temperature airflow that has passed over the high temperature side condenser 3 can be applied to the dew prevention pipe 32. While using as a cooling means of the refrigerant | coolant in the dew prevention pipe 32, the cooling of a refrigerant | coolant can be suppressed.

The temperature T1 of the refrigerant flowing in the dew prevention pipe 32 (refrigerant flow path) located in the vicinity of the inlet of the circulation pump 33 is determined by the ability of the cooling means (the heat radiation fins 34 and the heat radiation fan 4). This temperature T1, the temperature T0 of the refrigerant flowing in the dew condensation prevention pipe 32 located in the vicinity of the outlet of the high temperature side evaporator 3B, the ANTOINE constants A, B, C of the refrigerant, and the outlet of the high temperature side evaporator 3B The pressure difference Pg due to the difference in position head between the vicinity and the vicinity of the inlet of the circulation pump 33 and the flow area difference of the dew prevention pipe 32 at these positions (near the outlet of the high temperature side evaporator 3B / near the inlet of the circulation pump 33) In order to generate bubbles in the refrigerant flowing in the dew prevention pipe 32 and the pressure loss amount ΔP due to the pipe resistance of the dew prevention pipe 32 from the vicinity of the outlet of the high temperature side evaporator 3B to the vicinity of the inlet of the circulation pump 33. The superheat degree Ts of
T1 ≦ B / (A−log (Pg−ΔP + 10 ^{(AB / (C + T0)} )) − C + Ts (1)
It is preferable to satisfy the relationship.

  By reducing the refrigerant temperature T1 in the vicinity of the inlet of the circulation pump 33 to this level, cavitation can be sufficiently suppressed.

  Formula (1) is calculated | required in the following procedures.

In order to suppress the generation of bubbles in the vicinity of the inlet of the circulation pump 33, the refrigerant pressure in the pipe is equal to or higher than the vapor pressure in the portion, that is,
P1 ≦ P1 ′ (I)
It is preferable that In addition,
P1: Vapor pressure P1 ′ corresponding to the refrigerant temperature T1 flowing in the vicinity of the inlet of the circulation pump 33: In-pipe refrigerant pressure in the vicinity of the inlet of the circulation pump 33.

Here, from the positional relationship between the vicinity of the high temperature side evaporator 3B outlet and the vicinity of the inlet of the circulation pump 33,
P1 ′ = P0 ′ + Pg−ΔP (II)
Is guided. In addition,
P0 ′: In-pipe refrigerant pressure near the outlet of the high temperature side evaporator 3B Pg: Water head difference between the vicinity of the outlet of the high temperature side evaporator 3B and the vicinity of the pump inlet Pressure difference ΔP: the pressure loss due to the piping resistance of the dew prevention pipe 32.

Further, since the refrigerant is in a liquid state in the vicinity of the outlet of the high temperature side generator 3B, the refrigerant pressure in the pipe is equal to or higher than the vapor pressure in the portion, that is,
P0 ≦ P0 '(III)
It is thought that. In addition,
P0: Vapor pressure corresponding to the refrigerant temperature T0 flowing in the vicinity of the outlet of the high temperature side evaporator 3B.

From (II) and (III) above,
P1 ′ ≧ P0 + Pg−ΔP (IV)
So,
P1 ≦ P0 + Pg−ΔP (V)
Thus, the relationship (P1 ≦ P1 ′) in the above (I) is satisfied.

Further, in the above (V), the generally well-known ANTOINE formula P0 = 10 ^{(AB / (T0 + C))} , log (P1) = AB− (C + T1)
(A, B, C: ANTOINE constant)
By substituting
T1 ≦ B / (A−log (Pg−ΔP + 10 ^{(AB / (C + T0)} ) − C (VI)
Is guided.

  In other words, it is preferable that the refrigerant temperature T1 flowing in the vicinity of the inlet of the circulation pump 33 is low enough to satisfy (VI). The allowable range can be increased. By considering the degree of superheat Ts, it is possible to increase the degree of freedom in piping design within a range where an effect of suppressing cavitation can be obtained. The above formula (1) is derived by the above procedure.

  Each parameter in the above formula (1) can be specified as follows.

  ΔP is determined from the diameter, length, shape, surface roughness, and flow rate of refrigerant flowing through the dew condensation prevention pipe 32. This value can be confirmed by actually removing the piping and conducting a hydraulic experiment.

  Pg is the positional relationship in the height direction between the high temperature side evaporator 3B and the circulation pump 33, the flow area of the dew prevention pipe 32 near the outlet of the high temperature side evaporator 3B, and the dew prevention pipe 32 near the inlet of the circulation pump 33. It is calculated | required from the relationship with the flow path area.

  T0 and T1 are obtained by measuring the refrigerant temperature at each part while actually operating the heat dissipation system.

A, B, and C (ANTOINE constant) are uniquely determined by the type of refrigerant. For example, if the refrigerant is H ₂ O, A = 8.07, B = 1730.6, and C = 233.43 (when the unit of pressure is mmHg and the unit of temperature is ° C.).

Ts is determined by the type of refrigerant and the state of the evaporation surface (Ts on the rough surface is smaller than that on the smooth surface). For example, if the refrigerant is H ₂ O, Ts is greater than 0 ° C. and about 5 ° C. or less.

  The above contents are summarized as follows.

  The heat dissipation system according to the present embodiment is applied to a Stirling refrigerator, and is provided around the heat dissipating unit 18 (heat source) in the Stirling refrigerator 2, and is a high temperature side evaporator 3B that evaporates the internal refrigerant. (Evaporator), a first circulation circuit 30 that includes the high-temperature side condenser 3 (condenser) that receives the evaporated refrigerant and condenses the refrigerant, and returns the condensed refrigerant into the high-temperature side evaporator 3B; Including a dew prevention pipe 32 (refrigerant flow path) connected to the lower side of the side evaporator 3B and a circulation pump 33 attached to the dew prevention pipe 32. The refrigerant is guided to the outside of the high temperature side evaporator 3B, and the refrigerant is heated to the high temperature side. A second circulation circuit 31 returning to the evaporator 3B and a cooling means for cooling the refrigerant flowing between the high temperature side evaporator 3B and the circulation pump 33 are provided.

  By cooling the refrigerant, the refrigerant temperature in the dew prevention pipe 32 is lowered. As a result, the generation of bubbles (cavitation) is suppressed in the vicinity of the inlet of the circulation pump 33.

  When a piezoelectric pump is used as the circulation pump 33, a pulsation is generated in the flow of the refrigerant, so that a negative pressure tends to be generated on the upstream side of the circulation pump 33. As a result, cavitation is likely to occur, but the cooling unit solves the problems peculiar to the piezoelectric pump.

  As the cooling means, for example, a structure in which the radiation fins 34 are provided in the dew generation prevention pipe 32 located between the high temperature side evaporator 3B and the circulation pump 33 is conceivable. Thereby, an effective cooling means can be obtained with a simple structure.

  It is also conceivable to use an air blowing fan 4 (air blowing means) installed in the vicinity of the high temperature side condenser 3 as the cooling means. In this case, it is preferable to dispose a part of the dew prevention pipe 32 located between the high temperature side evaporator 3 </ b> B and the circulation pump 33 in the air flow generated by the blower fan 4.

  Also in this case, an effective cooling means can be obtained with a simple structure. Further, the fan 4 is also used as a cooling means, thereby saving space in the warehouse.

  With the above configuration, a Stirling cooler in which generation of noise, refrigerant pipe damage, and the like are suppressed is provided.

  Although the embodiments of the present invention have been described above, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is the figure which showed the Stirling refrigerator which concerns on one embodiment of this invention. It is the sectional side view which showed the Stirling refrigerator provided with the Stirling refrigerator which concerns on one embodiment of this invention. It is a figure explaining the basic composition of the heat dissipation system concerning one embodiment of the present invention. It is the figure which showed the 2nd circulation circuit in the thermal radiation system shown in FIG. It is a figure explaining the basic composition of the modification of the heat dissipation system concerning one embodiment of the present invention. It is the figure which showed the 2nd circulation circuit in the thermal radiation system shown in FIG.

Explanation of symbols

  1 Stirling cooler, 1A cooler body, 1B back of cooler body, 1C bottom of cooler body, 2 Stirling refrigerator, 3 high temperature side condenser, 3A duct, 3B high temperature side evaporator, 3C gas phase, 3D liquid phase, 4 Fan, 5 Low temperature evaporator, 5A Cold air duct, 6 Low temperature side refrigerant passage, 7 Internal cooling fan, 8 Drain pipe, 9 Drain pan, 10 Blower, 12 Casing, 13 Cylinder, 14 Piston, 15 Displacer, 16 Regenerator, 17 working space, 17A compression space, 17B expansion space, 18 heat radiation part, 18A tube, 19 heat absorption part, 20 inner yoke, 21 movable magnet part, 22 outer yoke, 23 linear motor, 24 piston spring, 25 displacer spring 26 Displacer rods, Seven back pressure, 30 first circulation circuit, 31 a second circulation circuit, 32 outburst prevention pipe, 33 a circulating pump, 34 heat dissipating fins, 180, 190 heat exchanger.

Claims (5)

A first circulation circuit that is provided around a heat source and includes an evaporator that evaporates an internal refrigerant and a condenser that receives the evaporated refrigerant and condenses the refrigerant, and returns the condensed refrigerant into the evaporator. When,
A second circulation circuit including a refrigerant flow path connected to the lower part of the evaporator and a circulation pump attached to the refrigerant flow path, guiding the refrigerant to the outside of the evaporator, and returning the refrigerant into the evaporator; ,
A heat dissipating system comprising cooling means for cooling the refrigerant flowing between the evaporator and the circulation pump.   2. The heat dissipation system according to claim 1, wherein the cooling means includes a heat dissipation fin provided in the refrigerant flow path located between the evaporator and the circulation pump. Further comprising air blowing means installed in the vicinity of the condenser;
The heat dissipation system according to claim 1, wherein the cooling unit includes the air blowing unit. A temperature T1 of the refrigerant flowing in the refrigerant flow path located in the vicinity of the inlet of the circulation pump in the second circulation circuit;
A temperature T0 of the refrigerant flowing in the refrigerant flow channel located near the outlet of the evaporator in the second circulation circuit;
Antoine constants A, B, C of the refrigerant,
A pressure difference Pg due to a position head difference between the vicinity of the outlet of the evaporator in the second circulation circuit and the vicinity of the inlet of the circulation pump in the second circulation circuit, and a flow area difference of the refrigerant flow path;
Pressure loss amount ΔP due to piping resistance of the refrigerant flow path from the vicinity of the outlet of the evaporator to the vicinity of the inlet of the circulation pump,
Superheat degree Ts for generating bubbles in the refrigerant flowing in the refrigerant flow path,
T1 ≦ B / (A−log (Pg−ΔP + 10 ^{(AB / (C + T0)} ) − C + Ts)
The thermal radiation system in any one of Claims 1-3 which satisfy | fills the relationship of these. A Stirling refrigerator having a low temperature part and a high temperature part as the heat source;
A Stirling refrigerator provided with the heat dissipation system according to claim 1.

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