Abstract: A plate type heat pipe having a hermetically sealed container installed so as to face a printed board on which at least one part to be cooled is mounted, wherein a block which passes through at least one main surface portion of the container is arranged within the container in a corresponding portion to the part(s) to be cooled.

Abstract: A heat dissipating conduit of loop cross section and housing a heat dissipating fin plate. The heat dissipating fin plate is formed by continuously folding a thin plate and has folding pitch adapted with size of the heat dissipating conduit, whereby heat from a thermal source can be transmitted through arbitrary point on the heat dissipating conduit. The heat dissipating conduit can be connected pipe, heat pipe, connected heat pipe, flexible planar heat pipe or bubble-type circulation pipe. The contact area is increased and the heat dissipating effect is enhanced. The noise is reduced and the structure is more compact.

Abstract: A computer fan assembly is described which may be constructed so as to be suitable for use in enclosures for notebook computers or laptops. A heat pipe may be secured to a housing of the computer fan assembly. The heat pipe may be located in a position so that heat is transferred away from the heat pipe by air passing through the housing. Heat may, for example, be conducted from the heat pipe and then convected by means of fins to the air passing through the housing.

Abstract: A heat sink for cooling a high power consumption device, such as a central processing unit (device), has extended heat transfer areas. In an embodiment, the extended heat transfer areas may include fins protruding from portions of a heat sink base. The extended heat transfer area of the heat sink may overhang an area of a circuit board adjacent to the high power consumption device. Low power consumption components, such as memory chips, can be mounted on the circuit board in close proximity to the high power consumption device and beneath the heat sink. The low power consumption component may have separate heat sinks that attach to the low power consumption components and extend beyond the base of the high power consumption device heat sink.

Abstract: An encapsulated circuit assembly and a method for making an encapsulated circuit assembly are disclosed. The assembly comprises a first printed circuit board, a second printed circuit board, and a heat transfer device. The second printed circuit board comprises a heatsink, and the heat transfer device couples between a device mounted on the first printed circuit board and the second printed circuit board for transferring heat from the device to the heatsink of the second printed circuit board.

Abstract: A heat sink comprising (a) a plate-shaped heat pipe including an upper plate member and a lower plate member to form a hermetically sealed cavity, and a working fluid enclosed therein, and (b) at least one heat radiating fin integrally formed with the upper plate member on an outer surface of the upper plate member.

Abstract: The present invention relates to a heat sink. More particularly, the present invention relates to a heat sink used for radiating heat from an integrated circuit package such as a micro-processor arranged in a portable type electronic apparatus such as a notebook type personal computer and also used for radiating heat from a hard disk unit used in an electronic apparatus. The heat sink comprises: a heat transmitting member for transmitting heat generated by a heating component; a holding section for holding the heat transmitting member; and a heat sink body having a space in which a cooling fan having at least blades and a drive motor is embedded, wherein a portion of the holding section for holding the heat transmitting member, the portion being located below the space, is cut out.

Abstract: A boiling cooler has a heat exchange part in which refrigerant vapor performs heat exchange with cooling water. The refrigerant vapor is produced from liquid refrigerant that is boiled and gasified by heat transferred from a heating element. In this boiling cooler, the refrigerant vapor can be cooled by cooling water having a thermal conductivity larger than that of air.

Abstract: A network-type heat pipe device is disclosed, wherein the network-type heat pipe device comprises a heat dissipating unit with a network shape, a heat absorbing unit of any desired shape, and two single flexible capillary pipes connecting the heat absorbing unit with the heat dissipating unit. The working fluid filled in the heat pipe is of a predetermined quantity smaller than the internal volume of the heat pipe. The inside diameters of the capillary pipes of the network-shaped heat dissipating unit and the connecting capillary pipes are small enough such that the vapor and liquid segments of the working fluid may distribute therein by capillary effect.

Abstract: A micro channel heat pipe and method of fabrication are disclosed. The micro channel heat pipe includes a wire cloth wick having micro capillary channels formed by a corrugation extrusion process. The wick is inserted into the heat pipe housing in a shrink fit, enhancing heat transfer. The porous nature of the wire cloth wick permits free passage of the working fluid within both the closed and open micro capillary channels, doubling the number of micro capillary channels available for heat transference.

Abstract: A structure of a super-thin heat plate comprising surrounding bodies having a thin plate shape and supporting body is disclosed. Each supporting body have function of capillarity and is enclosed within the surrounding bodies. The surrounding bodies and the supporting body are connected by a plurality of welding spots, and the edges are properly sealed. The supporting body is distributed uniformly by a whole web structure. Thus, the heat plate wick structure is very stable with a preferred performance of heat transfer and can be finished easily. In mass production, the structure still has a high stability.

Abstract: A notebook computer has a base housing with a heat-generating microprocessor therein, and a lid housing pivotally connected to the base housing. Operating heat from the microprocessor is transferred to the lid housing, for dissipation therefrom, via a specially designed thermosyphoning heat pipe structure formed from first and second heat pipes. The first heat pipe representatively has a rectangular cross-section, an evaporating portion thermally communicated with the microprocessor, and a coiled condensing portion centered about the lid hinge line and having a circularly cross-sectioned interior side surface portion defined by flat sides of the first heat pipe. The second heat pipe has a circular cross-section, an evaporating portion pivotally received within the coiled first heat pipe portion, and a condensing portion thermally communicated with the lid housing.

Abstract: A plate type heat pipe comprises: (1) a container including a plate member having a surface to which a heat generating part is connected, and another plate member positioned in such manner to face the plate member and to form a hollow portion therebetween, (2) a folded portion extended outward of the container, which is formed in such manner that end portions of respective plate member and another plate member are placed to form layers, and thus placed layers are folded in one side to cause the hollow portion to be hermetically sealed, and (3) a working fluid enclosed in the hollow portion.

Abstract: To realize a integrally constructed cooler of the heat pipe type which ensures the achievement of sufficient cooling capacity and the realization of a simple, compact and inexpensive cooler, that is especially low in height, employing and incorporating ingeniously a heat pipe, there is provided a heat pipe type cooler comprising: a heat receiving plate 3; a heat radiator having a configuration of a plurality of horizontally oriented heat radiation plates 5 extending vertically; and a heat pipe H having a generally U or V shaped profile, the middle portion of which is secured to the heat receiving plate 3: and wherein each end of the heat pipe H passes through the heat radiation plates 5.

Abstract: A cooling apparatus includes a refrigerant tank having a surface to which heating devices are attached and containing liquid refrigerant which is boiled and evaporated by heat transferred from the heating devices. The refrigerant tank includes a refrigerant chamber, a condensed liquid passage, heat insulating passage, and a communication passage. The heat insulating passage is formed between the condensed liquid passage and the refrigerant chamber. A vapor reverse flow reducing plate having a small hole is provided at the bottom of a lower opening of the heat insulating passage to reduce vaporized refrigerant (bubble) flowing into the refrigerant chamber from the heat insulated passage. Accordingly, the movement of the bubbles from the heat insulating passage to the refrigerant chamber via the communication passage is suppressed, and the heat radiation performance is improved.

Abstract: A network-type heat pipe device is disclosed, wherein the network-type heat pipe device comprises a heat dissipating unit with a network shape, a heat absorbing unit of any desired shape, and two single flexible capillary pipes connecting the heat absorbing unit with the heat dissipating unit. The working fluid filled in the heat pipe is of a predetermined quantity smaller than the internal volume of the heat pipe. The inside diameters of the capillary pipes of the network-shaped heat dissipating unit and the connecting capillary pipes are small enough such that the vapor and liquid segments of the working fluid may distribute therein by capillary effect.

Abstract: The invention provides a cooling device provided with a heat pipe, which is capable of effectively radiating heat from electronic equipment such as a small-sized computer. The cooling device with the heat pipe comprises a plate-like container made of heat transferring metal for containing a working fluid, and having a heat absorbing surface larger than that of the body to be cooled, a the heat transferring metal column, and a hollow portion in which the working fluid exists. An alternating embodiment of the cooling device with the heat pipe comprises a plate-like container made of heat transferring metal, a heat absorbing wall having a large heat absorbing surface, and a plurality of protrusion portions.

Abstract: This cooling apparatus can improve a radiation performance by increasing the boiling area and make it difficult to cause the burnout on boiling faces by filling the boiling faces with a refrigerant necessary for the boiling. In refrigerant chambers for reserving a refrigerant, there are inserted corrugated fins for increasing the boiling area. These corrugated fins are composed of lower corrugated fins arranged to correspond to the lower sides of the boiling faces for receiving the heat of a heating body, and upper corrugated fins arranged to correspond to the upper sides of the boiling faces, and these lower and upper corrugated fins and are individually held in thermal contact with the boiling faces of the refrigerant chambers. The lower corrugated fins and the upper corrugated fins are given a common fin pitch P and are individually inserted vertically in the individual refrigerant chambers to define the individual passages further into a plurality of small passage portions.

Abstract: A fan for a computing device. The fan includes a motor and a blade portion having a plurality of blades; however, the blade portion is located apart from the motor. A blade driving mechanism connects the motor to the blade such that the blade rotates when the motor is operating.

Abstract: An electronic assembly that may include a two-phase material that absorbs heat generated by an integrated circuit. The heat may be transferred from the integrated circuit to the two-phase material by a heat pipe. The two-phase material can absorb heat in an isothermal process utilizing the latent heat of the material. The isothermal process allows the two-phase material to absorb heat generated by the integrated circuit without raising the temperature of the assembly.

Abstract: This cooling apparatus can improve a radiation performance by increasing the boiling area and make it difficult to cause the burnout on boiling faces by filling the boiling faces with a refrigerant necessary for the boiling. In refrigerant chambers for reserving a refrigerant, there are inserted corrugated fins for increasing the boiling area. These corrugated fins are composed of lower corrugated fins arranged to correspond to the lower sides of the boiling faces for receiving the heat of a heating body, and upper corrugated fins arranged to correspond to the upper sides of the boiling faces, and these lower and upper corrugated fins and are individually held in thermal contact with the boiling faces of the refrigerant chambers. The lower corrugated fins and the upper corrugated fins are given a common fin pitch P and are individually inserted vertically in the individual refrigerant chambers to define the individual passages further into a plurality of small passage portions.

Abstract: A heat dissipating device is used for dissipating heat generated by a heat source, and includes a fluid container made of a heat conductive material, at least one circulating pipe made of a heat conductive material, and a heat dissipating fin unit. The fluid container has a device contacting side adapted to be placed in contact with the heat source, and a pipe connecting side opposite to the device contacting side. The fluid container contains an amount of working fluid therein. The working fluid is capable of changing into fluid vapor when absorbing the heat from the heat source. The fluid vapor is capable of changing into fluid condensate when cooled. The circulating pipe has a vapor input portion, a condensate output portion, and a plurality of interconnected turns between the vapor input and condensate output portions.

Abstract: A thermosyphon system is employed in conjunction with compact and/or dense configurations of electrical and/or electronic components to provide cooling. The thermosyphon cooling system is particularly advantageous in those systems in which the compact arrangement of circuit modules precludes the use of direct air cooling. The thermosyphon cooling system repositions the air cooling aspect of its cooling function to an exterior cabinet location distant from the circuit modules which can therefore be placed more closely together to shorten signal paths.

Abstract: A notebook computer has a base housing with a heat-generating microprocessor therein, and a lid housing pivotally connected to the base housing. Operating heat from the microprocessor is transferred to the lid housing, for dissipation therefrom, via a specially designed thermosyphoning heat pipe structure formed from first and second heat pipes. The first heat pipe representatively has a rectangular cross-section, an evaporating portion thermally communicated with the microprocessor, and a coiled condensing portion centered about the lid hinge line and having a circularly cross-sectioned interior side surface portion defined by flat sides of the first heat pipe. The second heat pipe has a circular cross-section, an evaporating portion pivotally received within the coiled first heat pipe portion, and a condensing portion thermally communicated with the lid housing.

Abstract: The invention relates to a cooling apparatus (10) based on heat energy bound to working fluid in phase transition, the cooling apparatus comprising, for conducting elsewhere the heat energy generated by an electronic component (7), elongated cooling elements (1; 6a, 6b; 9a-9f) containing working fluid and extending in at least two different directions forming a matrix of cooling elements, and a heat conducting material (8; 15) binding the matrix of the cooling elements. The cooling elements (6a, 6b; 9a-9f) are arranged parallel to a circuit board level (A) and in at least one direction deviating from the circuit board level (A).

Abstract: A cooling assembly for an integrated circuit chip module wherein an evaporator-cooled IC module is enclosed within an insulated housing and attached to a printed circuit board through an interconnect including a heating element embedded therein.

Abstract: To realize a integrally constructed cooler of the heat pipe type which ensures the achievement of sufficient cooling capacity and the realization of a simple, compact and inexpensive cooler, that is especially low in height, employing and incorporating ingeniously a heat pipe, there is provided a heat pipe type cooler comprising: a heat receiving plate 3; a heat radiator having a configuration of a plurality of horizontally oriented heat radiation plates 5 extending vertically; and a heat pipe H having a generally U or V shaped profile, the middle portion of which is secured to the heat receiving plate 3: and wherein each end of the heat pipe H passes through the heat radiation plates 5.

Abstract: The present invention provides a two-phase thermosyphon (100) that includes a sealed housing (105). The housing (105) includes a first outer surface, a second outer surface opposite the first outer surface, a first inner surface, and a second inner surface. The housing (105) is preferably formed of a first housing piece and a second housing piece that are attached in such a way as to form a sealed housing. A porous structural material (101) is disposed within the housing (105). A plurality of slots (103) are disposed within the porous structural material (101). The slots (103) preferably run substantially perpendicular to the general direction of vapor flow through the porous structural material (101) and provide increased heat dissipation in the two-phase thermosyphon (100).

Abstract: A heat sink comprising: a body having an envelope including a flexible portion for thermal contact with a heat source, the envelope being filled with a thermally conductive liquid; and a thermosyphon having one end disposed at least partly within the liquid in the body to absorb heat from the heat source and another end disposed outside the envelope to dissipate heat.

Abstract: A cooling apparatus for cooling a heating body such as a CPU by boiling and condensing refrigerant has a tank having a heating body mounting portion on which the CPU is mounted; a porous metallic sintered body arranged in the tank; and refrigerant contained in the tank. The tank has a pair of faced walls including a heat-receiving wall and a radiation wall. The porous metallic sintered body is arranged along the heat-receiving wall, and transports the refrigerant collected at the bottom of the tank to an adjacent portion of the heating body mounting portion by using a capillary action. Since the refrigerant is boiled at such a wide adjacent portion, a superheat degree of the heating body mounting portion can decrease. Furthermore, since the refrigerant collected at the bottom of the tank is transported to the adjacent portion by the capillary action, an area of the radiation wall soaked in the refrigerant becomes small.

Abstract: A thermosyphon system is employed in conjunction with compact and/or dense configurations of electrical and/or electronic components to provide cooling. The thermosyphon cooling system is particularly advantageous in those systems in which the compact arrangement of circuit modules precludes the use of direct air cooling. The thermosyphon cooling system repositions the air cooling aspect of its cooling function to an exterior cabinet location distant from the circuit modules which can therefore be placed more closely together to shorten signal paths.

Abstract: A cooling device includes a boiling unit and a condensing unit. A diffusion plate having a plurality of holes is formed into a thin-long shape, and is disposed in an upper tank of the condensing unit at an approximate center in an up-down direction so that an inner space of the upper tank of the condensing unit is divided into upper and lower parts in the up-down direction. Each hole opened in the diffusion plate has an opening area smaller than a sectional surface area of an introduction port of a gas-refrigerant introduction pipe, opened in the upper tank of the condensing unit. Thus, gas refrigerant flowing into the upper tank of the condensing unit through the gas-refrigerant introduction pipe is diffused to all the upper part of the upper tank along the surface of the diffusion plate while passing through the holes of the diffusion plate downwardly.

Abstract: The apparatus is a heat spreader for attachment to a device to be cooled, with heat pipes attached within holes in the heat spreader. Each of several heat pipes is soldered into a long hole formed between the top and bottom surfaces of a typical heat spreader, which is essentially a thick plate. The heat pipes extend out of one edge of the plate and connect the heat spreader to a heat sink such as an assembly of fins. In order to limit the overflow of solder when the heat pipes are soldered into the heat spreader, a shallow basin is formed in the edge of the plate around all the heat pipe entry holes. The basin creates sufficient additional volume to retain any excess solder which flows out of the holes, and prevents the solder from spreading onto the heat input surface of the heat spreader where it would adversely affect the thermal contact.

Abstract: A low electro-magnetic radiation emissions heat sink that dissipates heat away from an integrated circuit package by means of conduction to the electronic chassis. The heat sink may also include a ferrite ring for reducing electro-magnetic radiation emissions from the integrated circuit package by increasing the electrical impedance of the EMI transmission path between the integrated circuit package and the electronic chassis, thus reducing the capacitive coupling and RFI concerns of conductive heat dissipation. The heat sink of the present invention may also include fins that are external to the electronic chassis for greater heat dissipation by means of external air convection.

Abstract: A cooling system for an electronic equipment enclosure employs a flat plate heat pipe to deliver heat from the interior of the enclosure through a connector to a removable external heat sink. The heat pipe includes a metallic bottom plate having a depression therein containing a set of rods evenly spaced from one another. A top plate covers the bottom plate with the rods compressed therebetween. Channels formed between adjacent rods are partially evacuated and injected with an evaporative fluid. The fluid and its vapor circulate in the channels to convey heat from a warm end of the heat pipe to a cool end. The heat sink is of similar construction.

Abstract: The present invention provides a two-phase thermosyphon (100) and a method for forming the two-phase thermosyphon (100). The two-phase thermosyphon (100) includes a hermetically sealed housing (101) including a first outer surface (107), a second outer surface (109) opposite the first outer surface (107), a first inner surface (111), and a second inner surface (113). The two-phase thermosyphon (100) also includes a finned area (114) thermally coupled to the hermetically sealed housing (101), the finned area (114) including a plurality of fins (115) disposed on a part of the first outer surface (107). The two-phase thermosyphon (100) also includes a plurality of air feed through slots (105) disposed in the housing (101). The air feed through slots (105) underlie the fins(115) and provide increased heat dissipation by increasing the air flow about the fins (115). The present invention is particularly useful in applications that require a two-phase thermosyphon utilized in a generally horizontal orientation.

Abstract: A power module or other circuit is formed with transistor assemblies, each having one or more semiconductor slices electrically connected to one another and fixed to a supporting system. The supporting system includes a tubular element suited to allow the flood of a refrigerating and insulating fluid in the inside and which has the semiconductor slices directly welded on its external surface.

Abstract: A winding chain dissipating unit suitable for an electronic device is disclosed. The winding chain dissipating unit has a winding chain outer tube, a winding chain inner tube, and heat pipe within the winding chain inner tube. The inner diameter of the winding chain outer tube is matched with the outer diameter of the winding chain inner tube so as to have a smaller front end and a larger rear end. Moreover, an elastic element is installed at a position between the front end of the winding chain inner tube and the front wall of the winding chain outer tube so that the winding chain inner tube generates a continuously front pulling force to the winding chain outer tube. Once a wear from rotation friction therebetween is formed, the winding chain inner tube will move forwards gradually so as to automatically adjust and compensate the gap from the wear.

Abstract: A cooling assembly for an integrated circuit chip module wherein an evaporator-cooled IC module is enclosed within an insulated housing which features a moisture barrier on its outer wall surface.

Abstract: According to the present invention, a cooling apparatus using boiling and condensing refrigerant, includes a fluid separating plate for separating a high-temperature fluid from a low-temperature fluid, a refrigerant tank disposed on the side of the high-temperature fluid from the fluid separating plate, a refrigerant sealed into the refrigerant tank, a pair of communication pipes, one end of which is communicated with the refrigerant tank hermetically, a condensing portion communicated with the other end of the communication pipes and disposed on the side of the low-temperature fluid from the fluid separating plate, and a heat insulating material as a high-temperature portion-side heat insulating material coated on the outer periphery of the high-temperature-side communication pipe. In this way, it is possible to suppress a heat conduction from a high-temperature portion (high-temperature air) to the high-temperature-side communication pipe.

Abstract: A heat sink device for use in an electronic device for dissipating into the atmosphere outside a housing of the electronic device the heat generated by an electronic component disposed within the housing. The housing has a peripheral wall formed with a heat removal opening. A heat sink disposed within the housing comprises a metal body having a heat pipe portion, and a radiation fin attached to the body in the vicinity of the heat removal opening and opposed to the opening. The heat-generating electronic component, such as CPU, is held in contact with the metal body at a location away from the fin attached portion thereof.

Abstract: A method and apparatus for cooling electronic devices is suggested comprising of a thermally conductive, flexible, non-jointed cooling conduit able to house a coolant. The conduit is passed or pulled through apertures provided on two or more cold plates. The conduit and plates are then placed in thermal communication with the electronic device or assembly to be cooled. The flexibility of the conduit allows the conduit with plates to be rearranged as to conform to the contours of the device to be cooled.

Abstract: A low electromagnetic radiation emissions heat sink that dissipates heat away from an integrated circuit package by means of conduction to the electronic chassis. The heat sink may also include a ferrite ring for reducing electromagnetic radiation emissions from the integrated circuit package by increasing the electrical impedance of the EMI transmission path between the integrated circuit package and the electronic chassis, thus reducing the capacitive coupling and RFI concerns of conductive heat dissipation. The heat sink of the present invention may also include fins that are external to the electronic chassis for greater heat dissipation by means of external air convection.

Abstract: A two-phase or mono-phase heat-exchanger for at least one electronic power component wherein the heat-exchanger supports a plurality of heat exchange tubes, each having a heat exchange fluid therein, and wherein said heat-exchanger includes at least one rigid plate provided with zones for receiving portions of the heat exchange tubes and wherein the heat-exchanger includes opposite edges which are formed so as to be secured to edges of adjacent heat-exchangers in such a manner that front and rear surfaces of the at least one rigid plate of each heat exchange unit are coplanar when one heat-exchanger is secured to an adjacent heat-exchanger.

Abstract: A cooling device includes a refrigerant tank in which liquid refrigerant is boiled, and a radiator in which gas refrigerant is condensed. A connection pipe is formed in the radiator so that refrigerant communicates between the refrigerant tank and the radiator. An interior of the connection pipe is partitioned into a first communication passage and a second communication passage, and a restriction plate is provided between the first communication passage and a refrigerant-condensing passage of the radiator to prevent liquid refrigerant from flowing into the refrigerant-condensing passage. Thus, when heat-generating amount of a heat-generating member becomes larger so that liquid refrigerant is vehemently boiled in the refrigerant tank and a part of liquid refrigerant is blown upwardly together with refrigerant vapor, the restriction plate prevents the liquid refrigerant from flowing into the refrigerant-condensing passage of the radiator while gas refrigerant readily passes through the restriction plate.

Abstract: An assembly of N laser diode arrays. Each diode is fitted to the end of a base which forms the anode and is traversed by a hole. The holes of all the bases define a channel for the circulation of fluid for cooling the assembly of diode arrays. Each module includes an array, a base and a corresponding cathode. The modules are separated from each other by a flat joint or gasket.

Abstract: The invention provides a cooling device with a heat pipe, which is capable of effectively radiating heat from electronic equipment such as a small-sized computer. The cooling device with the heat pipe comprises a plate-like container made of heat transferring metal for containing a working fluid, and having a heat absorbing surface larger than that of the body to be cooled, a heat transferring metal column, and a hollow portion in which the working fluid exists. An alternating embodiment of the cooling device with the heat pipe comprises a plate-like container made of heat transferring metal, a heat absorbing wall having a large heat absorbing surface, and a plurality of protrusion portions.

Abstract: A cooling apparatus includes a refrigerant tank having a surface to which heating devices are attached and containing liquid refrigerant which is boiled and evaporated by heat transferred from the heating devices, and a radiator for radiating heat of the boiled and vaporized refrigerant in a radiating passage thereof. In the radiating passage, a inner fin and a projection to position and fix the inner fin are provided, and a predetermined gap is provided between the projection and a bottom surface of the radiating passage. Thus the refrigerant condensed and liquefied in the radiating passage can reach an outflow communicating portion while flowing through the fluid passage formed as the gap.

Abstract: Disclosed is a casing for an electronic device which includes a heat dissipation layer, inner and outer insulative layers along either side of the heat dissipation layer, and a heat pipe which has a portion in thermal-transfer contact with the heat dissipation layer. The heat dissipation layer has a thermal conductivity in a first range whereas the insulative layers have a thermal conductivity in a different, lower range. Preferably, the inner layer is either thicker than the outer layer, has a lower thermal conductivity than the outer layer, or both. Vent holes can be provided through the heat dissipation layer, and, if so, the holes are preferably covered by either the inner or outer layers. Only a portion of the casing need have the foregoing heat dissipation layer, inner and outer insulative layers, and heat pipe.

Abstract: A cooling apparatus using boiling and condensing refrigerant for cooling a heat generating unit, includes a refrigerant tank having a wall surface, for containing the refrigerant therein, a heat generating unit boiling the refrigerant in the refrigerant tank by heating, and a radiator disposed in communication with the refrigerant tank for condensing and liquefying the boiling refrigerant in the tank. An interior of the refrigerant tank is partitioned into a vapor passage for leading the boiling refrigerant to the radiator, a condensed liquid passage in which the condensed and liquefied refrigerant flows downwardly, and a communication path formed at a lower side thereof for communicating between the vapor passage and the condensed liquid passage. The condensed liquid passage is defined by a part of the wall surface.