Passive heat-dissipating fan system and electronic system containing the same

Abstract

A passive heat-dissipating fan system comprises an air-providing device, a cold-end passive heat-dissipating assembly, a hot-end passive heat-dissipating assembly, a separation device capable of guiding airflow to the cold-end and hot-end passive heat-dissipating assemblies, and a cooling device which is disposed in the separation device and has cold and hot ends. When the airflow from the air-providing device passes through the separation device and cooling device, airflow from the air-providing device is separated and then partially directed to the cold-end passive heat-dissipating assembly and partially directed to the hot-end passive heat-dissipating assembly respectively, expelling the heated airflow to an exterior of an electronic system. Because the temperature of the airflow passing through the cold-end passive heat-dissipating assembly is higher than that of dew point of air, the airflow passing through the cold-end passive heat-dissipating assembly can dissipate the heat generated by an electronic element without producing dew.

Description

BACKGROUND

The invention relates to a passive heat-dissipating fan system, and in particular to a passive heat-dissipating fan system having a cooling device with a cold end and a hot end, and using a separation device to direct airflow to the cold end and the hot end of the cooling device to dissipate heat from a heat source and expel waste heat in an electronic system.

In general, a fan comprises an impeller and a motor connected to the impeller. The motor is actuated by an electric power system to rotate the impeller to generate airflow to dissipate heat from a heat source. The number of the fans depends on the sites of heat sources located in an electronic system. Thus, when more heat sources are located at different sites in the electronic system, more motors and power are necessarily increased.

In FIG. 1, an electronic system 1 comprises an electronic element 2 (e.g. a processor), a cooling device 3 (e.g. a thermal electric cooler or a thermoacoustic cooler) disposed on the electronic element 2, and a fin structure 33 disposed on the cooling device 3. The cooling device 3 has two ends 31 and 32 contacting the electronic element 2 and the fin structure 33, respectively. When the cooling device 3 is actuated by an electric power system (not shown), the end 31 of the cooling device 3 becomes a cold end, absorbing heat from the heated electronic element 2 and transferring heat toward the end 32 of the cooling device 3, and the end 32 of the cooling device 3 becomes a hot end, transferring heat to the fin structure 33. When heat is dissipated from the fin structure 33, the waste heat still exists in the electronic system 1, which increases the working temperature and is easy to result in failure or malfunction of the electronic element 2 or other elements in the electronic system 1. On the other hand, when the temperature thereof decreases to the dew point or lower, water drops begin to condense on the cold end 31 of the cooling device 3; thus, the electronic element 2 and other elements may be damaged.

To overcome the described problem, the invention provides a passive heat-dissipating fan system to quickly dissipate heat from electronic components of the electronic system and expel waste heat to the exterior environment.

SUMMARY

The invention provides a passive heat-dissipating fan system for dissipating heat from electronic components to the exterior environment. The passive heat-dissipating fan system comprises an air-providing device, a cold-hot separation assembly connected to the air-providing device, at least one hot-end passive heat-dissipating assembly connected to the cold-hot separation assembly, and at least one cold-end passive heat-dissipating assembly connected to the cold-hot separation assembly. When the airflow from the air-providing device passes through the cold-hot separation assembly, airflow from the air-providing device is separated and partially directed to the cold-end passive heat-dissipating assembly and partially directed to the hot-end passive heat-dissipating assembly.

The air-providing device comprises an active fan and an air-providing pipe connected to the active fan. The cold-hot separation assembly comprises a separation device having a separation element therein and a cooling device with a cold end and a hot end. The cooling device is connected to the separation element and the cold and hot ends are respectively disposed on both sides of the separation element. A hot-end chamber and a cold-end chamber are defined in the separation device by the separation element and the cooling device, wherein the hot end of the cooling device is disposed in the hot-end chamber and the cold end of the cooling device is disposed in the cold-end chamber. The hot-end passive heat-dissipating assembly is connected to the hot-end chamber, and the cold-end passive heat-dissipating assembly is connected to the cold-end chamber. The hot-end passive heat-dissipating assembly comprises a hot-end pipe and a hot-end passive fan, and the hot-end pipe has two ends connected to the hot-end chamber and the hot-end passive fan, respectively. The cold-end passive heat-dissipating assembly comprises a cold-end pipe and a cold-end passive fan. The cold-end pipe has two ends connected to the cold-end chamber and the cold-end passive fan, respectively.

The heat dissipated from the cooling device is carried away by the airflow traveling to the hot-end dissipating assembly and is expelled to the exterior of the electronic system by the hot-end pipe. The high-temperature airflow can further rotate the hot-end passive fan; thus the airflow circulation in the electronic system can be increased.

The airflow passing through the cold-end chamber has lower temperature and travels to the cold-end dissipating assembly to dissipate heat from a heat source.

DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 is a schematic view of an electronic system equipped with a conventional dissipating device.

FIG. 2 is a schematic view of an electronic system equipped with a passive heat-dissipating fan system of the invention.

FIG. 3 is a partially enlarged perspective view of the passive heat-dissipating fan system of the invention.

FIG. 4 is a side view of FIG. 3.

DETAILED DESCRIPTION

In FIG. 2, an electronic system 1 of the invention comprises a housing 100 and a passive heat-dissipating fan system 4 disposed in the housing 100, at least one electronic element 2′ disposed in the housing 100, and at least one fin structure 21 disposed on one surface of the electronic element 2′. The passive heat-dissipating fan system 4 comprises an air-providing device 41 disposed on one side of the housing 100, a separation device 42 (shown by dotted circle) connected to the air-providing device 41, at least one cold-end passive heat-dissipating assembly 43 connected to one side of the separation device 42, at least one hot-end passive heat-dissipating assembly 44 connected to one side of the separation device 42, a cooling device 45 disposed in the separation device 42 (shown in FIG. 4). In this embodiment, two cold-end passive heat-dissipating assemblies 43 and one hot-end passive heat-dissipating assembly 44 are disclosed.

The air-providing device 41 comprises an active fan 411 and an air-providing pipe 412 connected to the active fan 411. The active fan 411, e.g. an axial fan or a centrifugal fan, can be driven to rotate by a power supplier. High pressure airflow generated by the active fan 411 is transmitted to the cooling device 45 disposed in the separation device 42 via the air-providing pipe 412.

In FIGS. 3 and 4, the separation device 42 comprises a separation element 421 therein. The cooling device 45 has a cold end 450c and a hot end 450h disposed on both sides of the separation element 421, respectively. In this embodiment, the cooling device 45 is a heat dissipation device, e.g., a thermal electric cooler or a thermoacoustic cooler, using the cold-hot separation technique to dissipate heat. A hot-end fin structure 451 and a cold-end fin structure 452 are disposed on the surfaces of the hot and cold ends 450h and 450c of the cooling device 45, respectively. By connecting the cooling device 45 to the separation element 421, the cold and hot ends 450c and 450h are respectively disposed on both sides of the separation element 421; thus, a hot-end chamber 422 and a cold-end chamber 423 can be defined in the separation device 42 by the separation element 421 and the cooling device 45.

In FIG. 2, the cold-end passive heat-dissipating assembly 43 comprises a cold-end pipe 431 and a cold-end passive fan 432. The cold-end pipe 431 has two ends connected to the cold-end chamber 423 and the cold-end passive fan 432, respectively. The cold-end passive fan 432 can be a motor-free axial fan or a motor-free centrifugal fan disposed on the fin structure 21. Alternatively, the cold-end passive fan 432 can directly blow the electronic element 2′.

The hot-end passive heat-dissipating assembly 44 comprises a hot-end pipe 441 and a hot-end passive fan 442. The hot-end pipe 441 has two ends connected to the hot-end chamber 422 and the hot-end passive fan 442, respectively. The hot-end passive fan 442 can be a motor-free axial fan or a motor-free centrifugal fan disposed on one side of the housing 100 to expel the waste heat from the hot-end chamber 422 to the exterior.

When the air-providing device 41 operates, air is drawn into the interior of the housing 100 by the air-providing device 41 and pressurized. The pressurized air is transmitted to the cooling device 45 disposed in the separation device 42 via the air-providing pipe 412. Because the hot-end chamber 422 and the cold-end chamber 423 defined in the separation device 42 are formed by the separation element 421 and the cooling device 45, the pressurized air is substantially divided into two parts: one part passes through the hot-end fin structure 451 disposed on the hot end 450h and enters the hot-end chamber 422, and the other part passes through the cold-end fin structure 452 disposed on the cold end 450c of the cooling device 45 and enters the cold-end chamber 423. The pressurized air passing through the hot-end chamber 422 has higher temperature and is transmitted via the hot-end pipe 441 to drive the hot-end passive fan 442. The pressurized air passing through the cold-end chamber 423 has lower temperature and is transmitted via the cold-end pipe 431 to drive the cold-end passive fan 432.

The waste heat from the cooling device 45 is carried away by the airflow which passes through the hot-end fin structure 451 and exhausted to the exterior of the electronic system 1 by the hot-end passive fan 442. Moreover, the high-temperature airflow can further rotate the hot-end passive fan 442, and thus the airflow circulation in the housing 100 can be increased. The low-temperature airflow passing through the cold-end fin structure 452 flows toward the fin structure 21 disposed on the electronic element 2′ via the cold-end passive fan 432; thus, heat from the electronic element 2′ can be rapidly dissipated. Due to the low temperature airflow passing through the dissipating fin structure 21 being higher than that of the cold end 450c of the cooling device 45, phenomenon such as dew accumulation can be prevented.

While the invention has been described with respect to preferred embodiment, it is to be understood that the invention is not limited thereto, but, on the contrary, is intended to accommodate various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A passive heat-dissipating fan system, comprising:

an air-providing device;

a cold-hot separation assembly connected to the air-providing device;

at least one hot-end passive heat-dissipating assembly connected to the cold-hot separation assembly; and

at least one cold-end passive heat-dissipating assembly connected to the cold-hot separation assembly, wherein when an airflow from the air-providing device passes through the cold-hot separation assembly, the airflow is separated, and directed to the cold-end passive heat-dissipating assembly and the hot-end passive heat-dissipating assembly, respectively.

2. The passive heat-dissipating fan system as claimed in claim 1, wherein the air-providing device comprises an active fan and an air-providing pipe connected to the active fan, and the active fan comprises an axial fan or a centrifugal fan.

3. The passive heat-dissipating fan system as claimed in claim 1, wherein the cold-hot separation assembly comprises a separation device having a separation element therein and a cooling device having a cold end and a hot end, wherein the cooling device is connected to the separation element and the cold and hot ends are respectively disposed on both sides of the separation element, and a hot-end chamber and a cold-end chamber are defined in the separation device by the separation element and the cooling device, wherein the hot end of the cooling device is disposed in the hot-end chamber and the cold end of the cooling device is disposed in the cold-end chamber.

4. The passive heat-dissipating fan system as claimed in claim 3, wherein the cooling device comprises a thermal electric cooler or a thermoacoustic cooler.

5. The passive heat-dissipating fan system as claimed in claim 3, wherein the hot-end passive heat-dissipating assembly is connected to the hot-end chamber, and the cold-end passive heat-dissipating assembly is connected to the cold-end chamber.

6. The passive heat-dissipating fan system as claimed in claim 5, wherein the hot-end passive heat-dissipating assembly comprises a hot-end pipe and a hot-end passive fan, and the hot-end pipe has two ends connected to the hot-end chamber and the hot-end passive fan, respectively.

7. The passive heat-dissipating fan system as claimed in claim 6, wherein the hot-end passive fan comprises a motor-free axial fan or a motor-free centrifugal fan.

8. The passive heat-dissipating fan system as claimed in claim 5, wherein the cold-end passive heat-dissipating assembly comprises a cold-end pipe and a cold-end passive fan, wherein the cold-end pipe has two ends connected to the cold-end chamber and the cold-end passive fan, respectively.

9. The passive heat-dissipating fan system as claimed in claim 8, wherein the cold-end passive fan comprises a motor-free axial fan or a motor-free centrifugal fan.

10. The passive heat-dissipating fan system as claimed in claim 3 further comprising a hot-end fin structure disposed on a surface of the hot end of the cooling device.

11. The passive heat-dissipating fan system as claimed in claim 3 further comprising a cold-end fin structure disposed on a surface of the cold end of the cooling device.

12. An electronic system with a passive heat-dissipating fan system, comprising:

a housing;

an air-providing device disposed in the housing;

a cold-hot separation assembly connected to the air-providing device;

at least one hot-end passive heat-dissipating assembly connected to the cold-hot separation assembly; and

at least one cold-end passive heat-dissipating assembly connected to the cold-hot separation assembly; and

at least one electronic element corresponding to the cold-end passive heat-dissipating assembly, wherein when an airflow from the air-providing device passes through the cold-hot separation assembly, the airflow is separated, and then partially directed to the cold-end passive heat-dissipating assembly and partially directed to the hot-end passive heat-dissipating assembly.

13. The electronic system as claimed in claim 12, wherein the hot-end passive heat-dissipating assembly comprises a hot-end pipe and a hot-end passive fan, wherein the hot-end pipe has two ends connected to the cold-hot separation assembly and the hot-end passive fan, respectively; and the cold-end passive heat-dissipating assembly comprises a cold-end pipe and a cold-end passive fan, wherein the cold-end pipe has two ends connected to the cold-hot separation assembly and the cold-end passive fan, respectively.

14. The electronic system as claimed in claim 13, wherein the hot-end passive fan comprises a motor-free axial fan or a motor-free centrifugal fan, and the cold-end passive fan comprises a motor-free axial fan or a motor-free centrifugal fan.

15. The electronic system as claimed in claim 12, wherein the air-providing device comprises an active fan and an air-providing pipe connected to the active fan, and the active fan comprises an axial fan or a centrifugal fan.

16. The electronic system as claimed in claim 12, wherein the cold-hot separation assembly comprises a separation device having a separation element therein and a cooling device having a cold end and a hot end, wherein the cooling device is connected to the separation element and the cold and hot ends are respectively disposed on both sides of the separation element, and a hot-end chamber and a cold-end chamber are defined in the separation device by the separation element and the cooling device, wherein the hot end of the cooling device is disposed in the hot-end chamber and the cold end of the cooling device is disposed in the cold-end chamber.

17. The electronic system as claimed in claim 16, wherein the cooling device comprises a thermal electric cooler or a thermoacoustic cooler.

18. The electronic system as claimed in claim 16, wherein the hot-end passive heat-dissipating assembly is connected to the hot-end chamber, and the cold-end passive heat-dissipating assembly is connected to the cold-end chamber.

19. The electronic system as claimed in claim 16 further comprising a hot-end fin structure disposed on a surface of the hot end of the cooling device, and a cold-end fin structure disposed on a surface of the cold end of the cooling device.

20. The electronic system as claimed in claim 12 further comprising a fin structure disposed on a surface of the electronic element.