JP2008304093A - Evaporative cooling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaporative cooling system capable of cooling a heating element with high efficiency, to improve packaging density of a device having the heating element, and to achieve high performance. <P>SOLUTION: This evaporative cooling system is composed of evaporative cooling modules 10, 11, a liquid sending system composed of a liquid sending pump 50 and a tube 51, and supplying a refrigerant liquid to the evaporative cooling modules, an air supply system composed of air supply tubes 60, 61, and supplying warm air to the evaporative cooling module, an exhaust system composed of an exhaust pump 70 and a tube 71, and discharging the air including refrigerant vapor from the evaporative cooling modules, a returning system composed of a primary heat exchanger 80 and a return tube 81, condensing the refrigerant vapor and returning the same to the liquid supply system, and a heat exhausting system composed of a secondary heat exchanger 90 and a tube 91, and discharging the heat absorbed from the primary heat exchanger. The warm air of high saturated vapor pressure and low relative humidity, and the refrigerant liquid are supplied to an evaporation plate kept into contact with the heating element over the inside of the evaporative cooling modules 10, 11, thus the evaporation is promoted and high cooling efficiency can be achieved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cooling system for a heating element, and more particularly to a vaporization cooling system suitable for information platform devices such as servers, networks, and storages that require high performance and high density.

  Conventionally, evaporative cooling is known as means for efficiently cooling a heating element such as a processor, an LSI, an electronic device, a power device, and a power device. Compared to air cooling and liquid cooling using heat conduction and heat transfer from the heating element to the refrigerant, evaporative cooling using the latent heat of the refrigerant is considered promising for improving cooling efficiency and reducing the size and weight of the cooling system. Yes.

  For example, air cooling, water cooling, and vaporization cooling are compared for a 100 W heating element. Air and water cooling with specific heat of air of 1.0 J / g · K, density of 0.0012 g / cm 3, specific heat of water of 4.2 J / g · K, density of 1 g / cm 3, and heat of vaporization of 2300 J / g It is assumed that the temperature rise of the refrigerant at 30K is 30K. The weight ratio of the refrigerant necessary for cooling the heating element under this assumption is air cooling: water cooling: evaporative cooling = 3.3 g / s: 0.79 g / s: 0.043 g / s = 77: 18: 1, The volume ratio of the refrigerant is 2800 cm <3> / s: 0.79 cm <3> / s: 0.043 cm <3> / s = 64000: 18: 1, and it can be seen that evaporative cooling has orders of magnitude performance compared to air cooling and water cooling. However, the practical cooling performance greatly depends on the refrigerant supply means, vaporization conditions, and the like.

  Several known examples are known as evaporative cooling means. In US Pat. No. 6,085,831 (Patent Document 1), a semiconductor chip, which is a heating element, is covered with a jacket, and a refrigerant is circulated therein. The refrigerant liquid is vaporized by the heating element, the refrigerant vapor is cooled and condensed by the air cooling fin outside the jacket, the refrigerant liquid returns to the heating element again, and the refrigerant circulates inside the jacket.

  In Japanese Patent Laid-Open No. 2000-252671 (Patent Document 2), a circulation pipe is attached to a microprocessor that is a heating element. The refrigerant vapor vaporized by the heating element moves inside the pipe, and the vapor condenses and separates into refrigerant liquid and air in the heat exchange section consisting of air-cooled fins, and both are sent to the nozzle through separate pipes, and the refrigerant liquid is in the nozzle From the heat generating body to the surface of the heating element by the piezoelectric film, and the refrigerant liquid is again vaporized by the heating element to constitute a circulation system.

  In US Pat. No. 6,205,799 (Patent Document 3), a circuit board on which a semiconductor device, which is a heating element, is mounted is housed in a casing, and a refrigerant liquid is sprayed toward the heating element from a sprayer inside the casing. The vaporized refrigerant vapor is sent to the heat exchanger through a pipe connected to the casing, and the condensed refrigerant liquid is sent to the storage tank by the pump, and sent from the storage tank to the sprayer again and circulated. The sprayer is composed of a heater, a chamber, an opening, and the like formed on a silicon substrate in accordance with a thermal ink jet method that is a printer printing technique.

  In US Pat. No. 6,888,515 (Patent Document 4), a spray module is attached to a semiconductor which is a heating element, and a coaxial tube is connected to the module. The refrigerant liquid is injected from the pump through the inner tube of the coaxial tube to the heating element, the refrigerant vapor is recovered from the opening inside the module, sent to the condenser through the outer tube of the coaxial tube, and the liquefied refrigerant is sent from the condenser. It is sent to the storage tank, and is again injected into the heating element by the pump and circulates.

  In JP 2006-39916 A (reference 5), a steam generator is attached to a CPU that is a heating element. The refrigerant is vaporized inside the generator, and the refrigerant vapor is sent to a condenser connected to the generator, cooled by an air cooling fan, liquefied by the refrigerant, sent to the liquid receiving tank, and again from the liquid receiving tank to the generator. Sent to form a circulation cycle.

  In Japanese Patent Application Laid-Open No. 11-26665 (reference 6), a hollow heat sink is attached to the casing of a CPU that is a heating element, and a coolant is supplied by capillary action from a water storage pit inside the heat sink to the inner surface of the heat sink. Yes. The refrigerant evaporates inside the heat sink, the air containing the refrigerant vapor is sent to the heat exchanger and the dehumidifier through the pipe by the fan, and the refrigerant liquefied by the heat exchanger is returned again to the water pit of the heat sink by the pump, The air dried by the dehumidifier is returned to the heat sink by the compressor, and a circulation system is configured.

US Patent No. 6085831 JP 2000-252671 A US Pat. No. 6,205,799 US Pat. No. 6,889,515 JP 2006-39916 A Japanese Patent Laid-Open No. 11-26665

  In patent document 1 and patent document 2, since a refrigerant | coolant is enclosed with a jacket or circulation piping and a refrigerant | coolant vapor | steam and a liquid are mixed in the same space, the vapor pressure of the refrigerant | coolant of a heat generating body vicinity becomes high, and there exists a problem that it is hard to vaporize. is there. Further, since the jacket and the circulation pipe are integrated with the air-cooling fins, it is necessary to provide these mounting regions around the heating element, and there is a problem that the mounting density of the heating element cannot be increased.

  In Patent Document 3 and Patent Document 4, a sprayer or spray module for injecting a refrigerant liquid to a heating element, a heat exchanger or a condenser for condensing the refrigerant, a storage tank for storing the refrigerant, a pump for sending the refrigerant liquid to the spray, etc. Thus, a cooling system is configured. Since the refrigerant vapor and liquid are mixed in the same way as in Literature 1 and Literature 2, it is necessary to provide a spray mechanism with a thermal ink jet or a compressor in order to destroy the saturated vapor pressure layer near the heating element and promote vaporization. These have problems that hinder miniaturization and reliability.

  In Reference 5, the cooling system is composed of a steam generator attached to the heating element, an air-cooled condenser, a liquid receiving tank, and the like. However, as in References 1 to 4, the refrigerant vapor and the liquid are in the same circulation system. Since it is sealed, there is a problem that the vapor pressure of the refrigerant is increased inside the circulation system and the vaporization efficiency is lowered.

  In Patent Document 6, a hollow heat sink having substantially the same area as the heating element, a heat exchanger that cools and liquefies the refrigerant vapor evaporated inside the heat sink with an air cooling fan, a dehumidifier that heats exhaust from the heat sink, and a heat exchanger The cooling system includes a pump that returns the refrigerant liquid to the heat sink, a compressor that sends dry air from the dehumidifier to the heat sink, and the like. In a closed circulation system similar to Patent Document 1 to Patent Document 5, a dehumidifier is provided to lower the vapor pressure inside the heat sink and promote vaporization, but this hinders reduction in size and weight. Further, since the refrigerant liquid and the dry air are supplied to the heat sink from the same direction with respect to the heat sink, there is a problem that vaporization is increased and vaporization is difficult to vaporize in the rear as vaporization is performed in the front.

  As described above, the conventional technology has a problem that the evaporative cooling efficiency is low and it is difficult to reduce the size and weight of the cooling system. The main object of the present invention is to reduce the size and weight of the cooling system by efficiently performing evaporative cooling, improve the mounting density of the information platform device, and achieve high performance. For this reason, the evaporative cooling system suitable for higher density is provided by supplying the refrigerant and atmosphere based on the evaporative cooling principle and optimizing the evaporating conditions.

  The evaporative cooling model is obtained based on the Penman-Monteith method, assuming that the vaporized evaporation amount is proportional to the difference between the saturated vapor pressure and the atmospheric vapor pressure. The latent heat flux (heat removal density from the heating element) is La (W / cm 3), the heat of vaporization of the refrigerant is ε (J / g), the saturated vapor pressure is es (hPa), the vapor pressure of the atmosphere is ea (hPa), The coefficient can be expressed as (Equation 1) with k (g / cm 2 · s · hPa).

Latent heat flux La is the heat of vaporization epsilon, is proportional to the difference (es -e _a) the saturated vapor pressure and the vapor pressure, the percentage [psi (%) of the vapor pressure ea atmosphere for the saturated vapor pressure e _s, so-called relative humidity (Equation 1) can be rewritten as (Equation 2). In order to increase the latent heat flux La, _a refrigerant having a large vaporization heat ε is used, vaporization is performed under a condition where the saturated vapor pressure _es is high, and the relative humidity ψ is decreased by decreasing the vapor pressure ea in the vicinity of the object to be cooled. This is very important.

  The coefficient k in the first term on the right side of (Expression 2) is the refrigerant supply means (refrigerant liquid amount, film thickness, thermal conductivity, thermal resistance, etc.), air supply means (air density, specific heat, wind speed, wind direction). Etc.) and the state of the vaporization surface of the heating element (affinity with refrigerant, surface shape, surface treatment, etc.). It is necessary to increase the coefficient k by expanding the effective area of the vaporization surface so that the refrigerant is easily vaporized from the heating element, supplying the refrigerant thinly and uniformly.

  Taking water having a relatively large heat of vaporization as an example, the heat of vaporization ε of the second term can be expressed by an approximate expression such as (Equation 3) with respect to temperature t (° C.). Even if the temperature t changes in the range from room temperature to (° C.) to a boiling point of 100 ° C., the temperature dependence of the vaporization heat ε is relatively small.

When the refrigerant is water, the saturated vapor pressure e _s in the third term can be expressed as (Equation 4) by the Tetens equation. As the temperature t increases, the saturated vapor pressure e _s increases exponentially. To increase the latent heat flux L _a, it is effective to increase the ambient temperature t of the cooling object neighborhood.

Similarly, in the case of water, the fourth term (1-ψ / 100) can be expressed as (Equation 5) using the relative humidity ψo (%) at room temperature to and the Tetens equation. In order to increase the value of the fourth term, the ambient temperature t is set higher than the normal temperature to, the relative humidity ψ at the temperature t is lowered, and the vapor pressure e _{a of the} atmosphere is lowered.

Figure 13 shows the dependence of the latent heat flux L _a with respect to the temperature t in the case of using water as coolant. By substituting (Equation 3) to (Equation 5) into (Equation 2), normal temperature to is 20 ° C., relative humidity ψo is 60% RH, and coefficient k is a parameter. Latent heat flux L _a from 13 as the temperature t increases is can be seen that large.

In evaporative cooling, the equilibrium state between heat generation density and latent heat flux L _a (heat removal density) per unit area of the heating element is cooling temperature. To increase the evaporative cooling efficiency by increasing the quantity of heat removed from the heating element, with a large refrigerant heat of vaporization epsilon, spread the area of the region where the refrigerant vaporizes, increasing the latent heat flux L _a by the method described above It is important.

Features of exemplary embodiments of the present invention, by attaching the vaporizing plate having a larger area than the heating portion of the heating element to the heating element, widening the area of the region latent heat flux L _a is obtained, increase the overall heat removal quantity Let

Another feature of the exemplary embodiment of the present invention is that the surface of the vaporization plate in contact with the heating element is given a surface treatment, shape processing, or capillary body that increases the affinity with the refrigerant, thereby increasing the effective area and the refrigerant. the liquid was supplied into a thin film, by increasing the coefficient k, increases the latent heat flux L _a.

Yet another feature is that by supplying the maximum temperature following the hot air of the heating element into the vaporizing plate, lowering the relative humidity ψ to increase the saturated vapor pressure e _s near vaporizing plate, increases the latent heat flux L _a. Similarly, by providing the upper limit temperature or less of the refrigerant liquid in the heating element to the vaporizing plate, it is possible to obtain the effect of increasing the latent heat flux L _a.

Yet another feature is that by supplying the refrigerant liquid and air to the vaporization plate from different directions, the air is supplied while keeping the relative humidity ψ low, and the saturated vapor pressure layer on the vaporization plate surface is removed. by lowering the vapor pressure e _a to improve the latent heat flux L _a.

  Still another feature is a mechanism that generates warm air by supplying warm air generated by the second heating element to the vaporizing plate of the first heating element in the configuration having the first and second heating elements. Reduce the size of the air supply system by omitting.

  Yet another feature simplifies the coolant feeding system by supplying the coolant by its own weight to the vaporizing plate from a position higher than the heating element.

  Yet another feature is that an exhaust system that forcibly exhausts air containing refrigerant vapor from the vaporization plate performs liquid supply or air supply with the vaporization plate side being a negative pressure relative to normal pressure, and condenses the refrigerant vapor from the exhaust. Recirculation is performed with the reflux side returning the refrigerant liquid to the liquid supply system as a positive pressure, and the components of the liquid supply system or the air supply system and the reflux system are reduced.

  Yet another feature is that the planar heating elements are arranged substantially vertically, supply the refrigerant liquid to the upper part of the vaporization plate, and discharge the air containing the refrigerant vapor and the residual liquid of the refrigerant liquid from the lower part of the vaporization plate. Thereby, it becomes a liquid feeding system or discharge system suitable for a vertical heat generating body, and a cooling system can be reduced in size.

Still another feature is a closed circuit system comprising a liquid feed system for supplying refrigerant to the vaporization plate, an exhaust system, and a reflux system for returning the refrigerant to the liquid feed system, and an air feed system for taking in air from the outside air, an exhaust system, and the outside air. An open circuit system comprising a reflux system for discharging air is configured. Accordingly, the refrigerant while circulating in the closed circuit system, to supply low air vapor pressure e _a by utilizing the ambient air with a simple open circuit system to the vaporizing plate increasing the latent heat flux L _a.

  Yet another feature is that the first refrigerant vapor that has taken heat from the heating element in the primary heat exchange system is cooled and condensed by the second refrigerant, and the second refrigerant is the second refrigerant in the secondary heat exchange system. By exhausting the heat absorbed from one refrigerant vapor, the system that recirculates from the exhaust through the primary heat exchange system is downsized, and the secondary heat exchange system keeps the exhaust heat area away from the surroundings of the heating element, thereby cooling efficiency To improve.

  Yet another feature is that the required amount of heat is supplied to the vaporization plate by controlling the amount of liquid delivered, the temperature of liquid delivered, the amount of air delivered, or the temperature of air delivered according to the amount of heat generation, power consumption, operating rate, or temperature of the heating element. Refrigerant and air are supplied for efficient evaporative cooling.

According the first aspect of the present invention to the fifth means, the even for high heat density heating element to increase the latent heat flux L _a evaporative cooling can be efficiently performed, the thirteenth means from the sixth Accordingly, the cooling system including the liquid supply system, the air supply system, the exhaust system, the reflux system, and the like can be reduced in size and weight. These means have an effect of improving the mounting density of main devices such as processors and LSIs and providing higher performance, particularly in information platform devices such as servers, networks and storages.

  Hereinafter, an embodiment of an evaporative cooling system according to the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of an evaporative cooling system according to a first embodiment of the present invention, and shows an example in which the present invention is applied to a blade server system. The blade server system includes a plurality of blade servers 40, a backplane, an I / O module, a switch module, a storage module, a management module, a power supply module, an air cooling fan module, and the like connected thereto, and a server chassis 41 that houses them. Consists of. The blade server 40 includes a processor on which the vaporization cooling modules 10 and 11 are mounted, a chip set 20, a memory module 21, a motherboard 30, a connector 31 for connecting to a backplane, and a case that covers these.

  The evaporative cooling system includes evaporative cooling modules 10 and 11 that are in contact with a processor that is a heating element, a liquid supply system that includes a liquid supply pump 50 and a liquid supply tube 51 and supplies refrigerant liquid to the evaporative cooling modules 10 and 11, and an air supply An air supply system comprising tubes 60 and 61 for supplying air to the evaporative cooling modules 10 and 11, an exhaust system comprising an exhaust pump 70 and an exhaust tube 71 for exhausting air containing refrigerant vapor from the evaporative cooling modules 10 and 11; A primary heat exchanger 80, a reflux tube 81, and an exhaust port 82, a reflux system that condenses the refrigerant vapor and returns to the liquid feed system, a secondary heat exchanger 90, a water feed tube 91, and a water return tube 92. And an exhaust heat system that exhausts heat absorbed from the primary heat exchanger.

  FIG. 2 is a configuration diagram of the evaporative cooling module 10, and FIG. 3 is a cross-sectional view thereof. The processor package 100 to which the evaporative cooling module 10 is mounted includes a processor chip 101 that is a heating element, a cap 102 that is in close contact with the chip 101, and a package substrate 103 to which the chip 101 is connected, and is connected to the motherboard 30 via a socket 104. Is done. In the evaporative cooling module 10, a vaporization plate 110 that is in contact with the cap 102 via a heat conductive material 105, a wick 111 formed on the surface of the vaporization plate 110, a liquid supply tube 51, an air supply tube 60, and an exhaust tube 71 are connected. It consists of a jacket 109.

  The heat generated by the processor chip 101 is conducted to the vaporization plate 110 through the cap 102 and the heat conductive material 105. The refrigerant liquid supplied from the liquid feeding tube 51 spreads on the surface of the vaporization plate 110 due to the capillary action of the wick 111 like the liquid feeding flow 112. The warm air heated by the heat generated by the chipset 20 and the memory module 21 is sucked into the jacket 109 from the air supply tube 60 by the exhaust pressure of the pump 70 like the air flow 113. The refrigerant liquid spreading on the surface of the vaporization plate 110 is vaporized into the warm air inside the jacket by the heat from the processor chip 101 like the vaporization flow 115. The air containing the refrigerant vapor and the residual liquid of the refrigerant liquid that has not been vaporized are discharged from the exhaust tube 71 by the pump 70 as in the exhaust flow and the drainage flow 115.

  FIG. 4 is a configuration diagram of the primary heat exchanger 80 and the secondary heat exchanger 90. The primary heat exchanger 80 includes an inner tube 120 and an outer tube (cooling tube) 121 connected to the exhaust tube 71, a condenser that condenses the refrigerant vapor from the exhaust, a liquid tank 122 that stores the condensed refrigerant liquid, and a condensation. The chamber 123 is configured to store the remaining residual air and an exhaust port 82. The secondary heat exchanger 90 includes a radiator 130 and a fan 131 that air-cools the radiator. The cooling water is supplied from the secondary heat exchanger 90 to the outer tube (cooling pipe) 121 by the water supply pump 93 and the water supply tube 91 to cool the refrigerant vapor passing through the inner tube 120, and the hot water absorbed from the refrigerant vapor is returned to the water. The heat is returned to the radiator 130 through the tube 92 and cooled, and the exhaust heat from the hot water is released to the outside air like the exhaust heat flow 132.

  FIG. 7 is a functional diagram of the evaporative cooling system according to the first embodiment. The refrigerant liquid is sent to the vaporization cooling module 10 from the liquid feed system including the liquid feed pump 50 and the liquid feed tube, and is vaporized into the refrigerant vapor inside the module 10. The refrigerant vapor is composed of the exhaust pump 70 and the exhaust tube 71 together with the remaining liquid. The refrigerant is sent from the exhaust system to the primary heat exchanger 80, the refrigerant vapor condenses inside the heat exchanger 80 and returns to the refrigerant liquid, and the refrigerant liquid is composed of the primary heat exchanger 80 and the reflux tube 81. To the liquid feeding system again, and the refrigerant forms a closed circuit circulation system. The outside air heated by the chip set 20 enters the evaporative cooling module 10 from the air supply system including the air supply tube 60, and the air containing the refrigerant vapor is sent from the exhaust system to the primary heat exchanger 80, and the refrigerant vapor condenses. The remaining dry air is discharged from the exhaust port 82 to the outside air, and the air forms an open circuit system.

In the first embodiment, with the above-described configuration, an atmospheric condition of a normal room temperature of 25 ° C. and a room humidity of 60% RH is applied to a processor having a maximum power consumption of about 100 W, an upper limit operating temperature of 65 ° C., and a package size of about 4 cm square. Then, the vaporizing plate 110 made of water and copper as the refrigerant liquid is about 5 cm square, and the air supply temperature is about 40 ° C., so that a latent heat flux of about 4 W / cm ² is obtained to perform evaporative cooling. As the refrigerant material, water, a fluorine-based inert liquid, or the like can be considered. In Example 1, water having a relatively large heat of vaporization is used. The processor operating rate, power consumption, package temperature, or the like is monitored with respect to fluctuations in the power consumption of the processor, that is, the heat generation amount. Although controlled, liquid supply temperature and air supply temperature can also be used as other control factors. When using processors with different specifications such as maximum power consumption and package size, the material and size of the refrigerant material and vaporization plate are designed together with the control factors. As shown in FIG. 13, the temperature t of the horizontal axis is related to the liquid supply temperature and the air supply temperature, and the liquid supply amount and the air supply amount are related to the coefficient k.

  According to the first embodiment, since the vaporization plate 110 having a larger area than the processor chip 101 which is a heating element is used, a region where heat is diffused to the vaporization plate and a latent heat flux can be obtained is widened. The amount of heat removal can be increased by promoting vaporization rather than vaporizing directly from the surface of 102. In order to efficiently expand the vaporization region, a heat pipe or a vapor chamber may be used as the vaporization plate. A wick 111 is attached to the surface of the vaporizing plate 110. The wick 111 is a capillary body formed of a net-like fiber. Due to the capillary phenomenon of the wick 111, the refrigerant liquid spreads thinly and evenly on the surface of the vaporization plate 110, the thermal resistance of the refrigerant liquid decreases, the effective area of the vaporization region increases, and the latent heat flux can be improved. In order to obtain the same effect, an affinity coating or fine unevenness processing may be applied to the vaporization plate 110 surface instead of the capillary body.

  In the first embodiment, the air inlets of the air supply tubes 60 and 61 open near the chip set 20 or the memory module 21 around the processor chip 101. That is, the air supplied to the evaporative cooling modules 10 and 11 is air that has exchanged heat with the chip set 20 or the memory module 21. Thereby, the effect of cooling the memory module and the chip set is obtained, and warm air is supplied to the vaporizing plate 110. As the temperature of the air increases, the saturated vapor pressure increases, so the relative humidity decreases and the latent heat flux increases. Further, since the heat generated by the chipset 20 and the memory module 21 is utilized, it is not necessary to provide a dedicated heating mechanism for warming the air, and the negative pressure due to the suction of the exhaust pump 70 can be used from the air supply tubes 60 and 61. Since air is taken in, the air supply system can be simplified. In addition, since the temperature of the warm air does not exceed the upper limit temperature of the processor chip 101, there is no problem in operation and reliability.

  The refrigerant liquid is supplied to the vaporizing plate 110 from the direction of the liquid supply flow 112 and the air is supplied from the direction of the air flow 113. By supplying air from a direction different from that of the refrigerant liquid, the relative humidity of the air can be kept low up to the surface of the vaporization plate 110, and vaporization can be promoted by removing the saturated vapor pressure layer on the surface of the vaporization plate 110 by wind pressure. In addition, the refrigerant liquid is supplied to the upper part of the vaporization plate 110 standing vertically, and the refrigerant liquid spreads on the surface of the vaporization plate 110 in combination with the gravity flow of the liquid itself and the capillary effect of the wick 111, and efficiently vaporizes. The remaining liquid remaining without being vaporized is also automatically discharged together with the refrigerant vapor from the lower part of the vaporization plate 110 by its own weight, so that the liquid feeding system and the exhaust system can be simplified.

  The refrigerant liquid circulates in a closed circuit system including a liquid feeding system, an exhaust system, and a reflux system, and air passes through an open circuit system that returns from the outside air to the outside air through the air feeding system, the exhaust system, and the reflux system. Since air with a low vapor pressure is supplied to the vaporization plate 110 by using outside air, vaporization is promoted. The exhaust gas whose vapor pressure has increased goes to the recirculation system and the refrigerant vapor is condensed, so that the exhaust gas is returned to the outside air with the vapor pressure lowered. Since the refrigerant circulates, it is not necessary to replenish frequently. However, when the refrigerant vapor slightly leaks from the exhaust port 82 and the liquid amount in the liquid tank 122 decreases, secondary heat exchange with the evaporative cooling refrigerant is performed. Using the same refrigerant in the vessel, the vaporization cooling refrigerant may be automatically replenished to the liquid tank 122 from the water supply tube 91 or the water return tube 92 through the bypass pipe.

  The heat flow is emitted from the processor chip 101 and is conducted to the cap 102, the heat conductive material 105, and the vaporization plate 110, is transferred to the refrigerant vapor as latent heat, passes through the exhaust system, and is condensed in the condenser of the primary heat exchanger 80. As a result, the latent heat is transferred to the cooling water of the secondary heat exchanger 90 and released from the radiator 130 to the outside air as the exhaust heat flow 132. In order to cool and condense the refrigerant vapor, water cooling by the condensers 120 and 121 is more efficient than air cooling. Therefore, the primary heat exchanger 80 is downsized, for example, a part of a server rack shelf or a side panel. It can be provided on a back panel or the like. Further, since the primary heat exchanger 80 and the secondary heat exchanger 90 which is a heat exhausting place to the outside air are separated, the server chassis 41 and the primary heat exchanger 80 are stored in the server rack. Thus, the secondary heat exchanger 90 can be placed outside the room such as a data center, and the indoor air conditioning load, that is, the air conditioning power can be reduced without raising the room temperature.

  FIG. 5 is a block diagram of the evaporative cooling system according to the second embodiment of the present invention, and FIG. The evaporative cooling system according to the second embodiment is different from the first embodiment in that the air supply system includes the warm air blower 62 and the air supply tubes 60 and 61, and the exhaust system includes the exhaust tube 71.

  In the second embodiment, the vaporization cooling modules 10 and 11 are attached to the processor, and the refrigerant liquid is vaporized from a vaporization plate having a larger area than the processor chip and having a capillary body on the surface. The refrigerant liquid is supplied from the upper part of the evaporative cooling modules 10 and 11 via the liquid supply tube 51, and the hot air is supplied from the hot air blower 62 to the modules 10 and 11 via the air supply tubes 60 and 61 from a direction different from that of the refrigerant liquid. Then, the refrigerant vapor and the residual liquid are discharged from the lower part of the modules 10 and 11, and the refrigerant liquid collected and condensed in the primary heat exchanger 80 returns to the modules 10 and 11 through the liquid feed pump 50 again. The refrigerant forms a closed circuit circulation system, and the air forms an open circuit system from the hot air blower 62 to the discharge port 82 of the primary heat exchanger 80. In the secondary heat exchanger 90, the heat absorbed by the refrigerant vapor from the processor is finally released to the outside air through the cooling water and the radiator.

  According to the second embodiment, by supplying warm air below the upper limit operating temperature of the processor chip, which is a heating element, from the warm air blower 62 to the evaporative cooling modules 10 and 11, the saturated vapor pressure inside the module increases, and The refrigerant liquid supplied from the liquid pump 50 is easily vaporized. Further, since the air containing the refrigerant vapor and the unvaporized residual liquid are discharged from the evaporative cooling modules 10 and 11 by the supply air pressure of the hot air blower 62, the exhaust pump 70 can be omitted from the exhaust system. With respect to fluctuations in the amount of heat generated by the processor, the latent heat flux, that is, cooling can be accurately performed by changing the air temperature and the air supply amount (wind speed) of the hot air blower 62 in accordance with the processor operating rate, power consumption, package temperature, and the like. Can control ability.

  FIG. 6 is a block diagram of the evaporative cooling system according to the third embodiment of the present invention, and FIG. 9 is a functional diagram. In the third embodiment, a blade chassis 42 is provided inside the server chassis 41, and a plurality of blade boards 30 are sealed therein. In order to perform evaporative cooling inside the blade chassis 42, the surfaces of the board 30, the vaporization plates 110 and 116 attached to the processor, the chipset 20, the memory module 21, and the connector 31 also serve as an affinity coating for the refrigerant liquid. A liquid-proof treatment is applied.

  Refrigerant liquid is supplied to the upper surface of the blade chassis 42 from a liquid feeding system including a liquid feeding pump 50 and a liquid feeding tube 51, and other than the blade server (I / O module, switch module, storage module, management module, power supply module, etc.). Warm air due to heat generation is taken into the blade chassis 42 from the air supply port 63 by the exhaust pressure of the exhaust pump 70, and the refrigerant liquid is vaporized from the vaporization plates 110, 116 and chips 20, 21 mounted on the board 30. The exhaust system including the exhaust pump 70 and the exhaust tube 71 discharges the refrigerant vapor and the unvaporized residual liquid from the lower surface of the evaporative cooling chassis 42, and the refrigerant liquid passes through the primary heat exchanger 80 and the reflux tube 81. The residual air is exhausted from the exhaust port 82.

  According to the third embodiment, not only the processor but also the peripheral chips on the board 30 can be vaporized and cooled, so there is no need to provide a vaporization cooling module, a liquid supply tube, and an air supply tube for each processor. It is possible to omit an air cooling fan for cooling the blade server system and to reduce the weight of the blade server system. Although the vaporization plate is attached to the processor in the third embodiment, the vaporization plate may be provided on the peripheral chip according to the amount of heat generation. It is also possible to attach a common vaporization plate across a plurality of chips, or to provide a vaporization plate that also serves as a liquid-proof cover.

  FIG. 10 is a functional diagram of the evaporative cooling system according to the fourth embodiment of the present invention. The basic configuration of the fourth embodiment is the same as that of the second embodiment, but the hot air blower 62 sucks air from the chamber of the primary heat exchanger 80 through the intake tube 64 and evaporates and cools the hot air from the air supply tube 60. The point of sending to the module 10 is different. The primary heat exchanger 80 has no exhaust port, and the air is closed circuit circulation around the hot air blower 62, the air supply tube 62, the evaporative cooling module 10, the exhaust tube 71, the primary heat exchanger 80, and the intake tube 64. The system and the refrigerant form a closed circuit circulation system around the air supply pump 50, the air supply tube 51, the module 10, the exhaust tube 71, the primary heat exchanger 80, and the reflux tube 81.

  According to the fourth embodiment, since both the refrigerant and the air are closed circuit systems, even if the refrigerant vapor is slightly mixed in the air after the refrigerant vapor is condensed in the primary heat exchanger 80, the first embodiment. The loss of refrigerant can be prevented compared to 2 and 2. The air remaining after condensation of the refrigerant vapor is sent to the hot air blower 62, the saturated vapor pressure is increased, the relative humidity is lowered, and the dried air is supplied to the evaporative cooling module 10, whereby vaporization is promoted.

  FIG. 11 is a functional diagram of the evaporative cooling system according to the fifth embodiment of the present invention. The basic configuration of the fifth embodiment is similar to that of the first embodiment except that the liquid coolant is warmed by the warm liquid heater 52 in the liquid feeding system, and the warm liquid below the upper limit temperature of the processor is supplied to the vaporization cooling module 10. Yes. By supplying the warm liquid, similar to the effect of supplying warm air and warm air in the first and second embodiments, the saturated vapor pressure around the vaporization plate inside the module 10 increases, the relative humidity decreases, and the vaporization efficiency improves. To do.

  The warm liquid heater 52 may be provided together with the liquid feed pump 50. In the air supply system, warm air generated by the heat generated by the peripheral chips may be supplied in the same manner as in the first embodiment. The temperature does not have to be performed. That is, it is possible to change the direction of the intake port of the air supply tube 60.

  FIG. 12 is a functional diagram of the evaporative cooling system according to the sixth embodiment of the present invention. In the sixth embodiment, the exhaust pressure of the exhaust pump 70 is used to set the vaporization cooling module 10 side to a negative pressure so that warm air is supplied from the air supply tube 60 to the vaporization plate, and the primary heat exchanger 80 side is By setting the positive pressure, the refrigerant liquid is sent from the reflux tube 80 to the liquid feeding tank 53. In the primary heat exchanger 80, if the valve of the exhaust port 82 is closed, the internal pressure of the chamber increases due to exhaust and drainage, and the refrigerant liquid flows from the liquid tank to the reflux tube 81. The liquid feed tank 53 is higher than the vaporization cooling module 10, and the refrigerant liquid flows down from the liquid feed tank 53 to the module 10 by its own weight and is supplied to the vaporization plate in contact with the processor 100.

  According to the seventh embodiment, since the liquid feed pump can be omitted from the liquid feed system by utilizing the exhaust pressure of the exhaust pump and the dead weight of the refrigerant liquid, the power required for the cooling system can be reduced and the blade server system can be downsized.

  The evaporative cooling system according to the present invention is particularly suitable for information platform devices such as servers, networks, and storages that require high performance and high density. For example, electronic devices such as PCs and mobile phones, generators, fuel cells, etc. It can be widely applied to uses for cooling equipment having a heating element, such as power equipment of automobiles, power equipment such as automobiles and railways.

It is a block diagram of the vaporization cooling system of Example 1 by this invention. It is a block diagram of the vaporization cooling module of Example 1 by this invention. It is sectional drawing of the vaporization cooling module of Example 1 by this invention. It is a block diagram of the primary and secondary heat exchanger of Example 1 by this invention. It is a block diagram of the vaporization cooling system of Example 2 by this invention. It is a block diagram of the vaporization cooling system of Example 3 by this invention. It is a functional diagram of the vaporization cooling system of Example 1 by this invention. It is a functional diagram of the evaporative cooling system of Example 2 by this invention. It is a functional diagram of the vaporization cooling system of Example 3 by this invention. It is a functional diagram of the vaporization cooling system of Example 4 by this invention. It is a functional diagram of the vaporization cooling system of Example 5 by this invention. It is a functional diagram of the vaporization cooling system of Example 6 by this invention. It is explanatory drawing of the vaporization cooling model which concerns on this invention.

Explanation of symbols

10, 11 ... Evaporative cooling module 20 ... Chipset, 21 ... Memory 30 ... Motherboard, 31 ... Connector 40 ... Blade server, 41 ... Server chassis, 42 ... Blade chassis 50 ... Liquid feed pump, 51 ... Liquid feed tube, 52 ... Warm liquid heater, 53 ... Liquid feed tank 60, 61 ... Air feed tube, 62 ... Warm air blower, 63 ... Air feed port, 64 ... Intake tube 70 ... Exhaust pump, 71 ... Exhaust tube 80 ... Primary heat exchanger (Condenser), 81. Reflux tube, 82 exhaust port 90 secondary heat exchanger, 91 water feed tube, 92 water return tube, 93 water feed pump 100 processor package, 101 processor chip (heating element) )
DESCRIPTION OF SYMBOLS 102 ... Cap, 103 ... Package board | substrate, 104 ... Socket, 105 ... Thermal conductive material 109 ... Jacket, 110, 116 Vaporization plate, 111 ... Wick 112 ... Liquid supply flow, 113 ... Air supply flow, 114 ... Vaporization flow, 115 ... Exhaust flow and drainage flow 120: inner tube, 121: outer tube, 122: liquid tank, 123: chamber 130: radiator, 131: air cooling fan, 132: exhaust heat flow.

Claims (13)

An evaporative cooling system that cools the heating element with the heat of vaporization of the refrigerant,
A vaporizing plate having a larger area than the heat generating portion of the heat generating element to diffuse heat in contact with the heat generating portion and vaporize the refrigerant liquid into the refrigerant vapor;
A liquid feed system for supplying a refrigerant liquid to the vaporization plate;
An air supply system for supplying air to the vaporization plate;
An exhaust system for exhausting air containing refrigerant vapor around the vaporization plate;
A vaporization cooling system comprising: a reflux system that condenses the refrigerant vapor of the exhaust system to recover a refrigerant liquid and return the refrigerant liquid to a liquid feed system.   The vaporization plate has one surface in contact with a heat generating portion of the heat generating element, and the other surface has affinity for the cooling liquid, or a capillary body is attached thereto. The evaporative cooling system according to claim 1.   The evaporative cooling system according to claim 1, wherein the air supply system supplies warm air lower than an upper limit temperature of the heating element to the vaporization plate.   The evaporative cooling system according to claim 1, wherein the liquid supply system supplies the refrigerant liquid having a temperature lower than an upper limit temperature of the heating element to the vaporization plate.   The evaporative cooling system according to claim 1, wherein the air supply system supplies air to the vaporization plate from a direction different from a supply direction of the refrigerant liquid to the vaporization plate of the liquid supply system. An evaporative cooling system for cooling the first and second heating elements,
A vaporization plate that contacts the first heating element and vaporizes the refrigerant liquid into refrigerant vapor;
A liquid feed system for supplying the refrigerant liquid to the vaporization plate;
An intake / exhaust system for sucking air from the vicinity of the heating element and supplying the air to the vaporization plate, and exhausting air containing refrigerant vapor from the vaporization plate;
A vaporization cooling system comprising: a reflux system that condenses refrigerant vapor from the exhausted air to collect a refrigerant liquid and return the refrigerant liquid to a liquid feeding system.   The evaporative cooling system according to claim 1, wherein the liquid supply system supplies the refrigerant liquid to the vaporization plate by its own weight from a higher position than the vaporization plate.   The evaporative cooling system according to claim 1, wherein the exhaust system includes a pump that forcibly exhausts to make the vaporization plate side have a negative pressure and the reflux system side to have a positive pressure. Holding means for holding the planar invention body substantially vertically;
A vaporizing plate in contact with the heating element to vaporize the refrigerant liquid into refrigerant vapor;
A liquid supply system for supplying the refrigerant liquid to the vaporization plate; an air supply system for supplying air to the vaporization plate;
An exhaust system for exhausting air containing refrigerant vapor from the vaporization plate;
A vaporization cooling system comprising: a reflux system that condenses the refrigerant vapor of the exhaust system to collect a refrigerant liquid and return the refrigerant liquid to a liquid feed system.   The evaporative cooling system according to claim 9, wherein the exhaust system is a discharge system that discharges the residual liquid of the refrigerant liquid from the vaporization plate together with the air containing the refrigerant vapor. An evaporative cooling system that cools the heating element with the heat of vaporization of the refrigerant,
A vaporizing plate in contact with the heating element to vaporize the refrigerant liquid into refrigerant vapor;
A liquid feed system for supplying a refrigerant liquid to the vaporization plate;
An air supply system that takes in air from outside air and blows it to the vaporizing plate;
An exhaust system for exhausting air containing refrigerant vapor from the vaporization plate;
With a reflux system that condenses the refrigerant vapor from the exhaust, returns the refrigerant liquid to the liquid delivery system in the previous period, and discharges residual air to the outside air,
The evaporative cooling is characterized in that the refrigerant circulates in a closed circuit including the liquid supply system, the exhaust system, and the reflux system, and the air circulates in an open circuit including the air supply system, the exhaust system, and the reflux system. system. An evaporative cooling system that cools the heating element with the heat of vaporization of the refrigerant,
A vaporizing plate that contacts the heating element and vaporizes the first refrigerant liquid into the first refrigerant vapor;
A liquid feed system for supplying the first refrigerant liquid to the vaporization plate;
An air supply system for blowing air to the vaporization plate;
An exhaust system for exhausting air containing the first refrigerant vapor from the vaporization plate;
A primary heat exchange system that cools the air in the exhaust system with a second refrigerant liquid and condenses the first refrigerant vapor to recover the first refrigerant liquid;
A reflux system for returning the first refrigerant liquid from the primary heat exchange system to the liquid feed system;
A vaporization cooling system comprising: a second heat exchange system that discharges heat absorbed by the second refrigerant liquid from the first refrigerant vapor. An evaporative cooling system that cools the heating element with the heat of vaporization of the refrigerant,
A vaporizing plate in contact with the heating element to vaporize the refrigerant liquid into refrigerant vapor;
A liquid feed system for supplying a refrigerant liquid to the vaporization plate;
An air supply system for supplying air to the vaporization plate;
An exhaust system for exhausting air containing refrigerant vapor around the vaporization plate;
A reflux system for condensing the refrigerant vapor of the exhaust system to collect the refrigerant liquid and returning it to the liquid feed system,
An evaporative cooling system that controls a liquid supply amount, a liquid supply temperature, an air supply amount, or an air supply temperature in accordance with a heat generation amount, power consumption, operation rate, or temperature of a heating element.

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