Patent Application
20170311485
The present invention relates to cooling devices used for cooling electronic appliances and methods of manufacturing the cooling devices and, in particular, to a cooling device with a natural-circulation type in which refrigerant vapor resulting from a phase change by receiving heat is transported without a driving source and condensed, and a method of manufacturing the cooling device.
In recent years, the required amount of information processing has increased with the improvement in information processing technologies and the rise of the Internet environment. Data centers (DCs) are installed and operated in various places in order to process huge volumes of data. Here, the data center (DC) means a specialized facility for installing and operating severs and data communication devices. In the data centers (DCs), the density of heat generation by electronic devices such as a server and a data communication device is extremely high; consequently, it is necessary to cool these electronic devices efficiently.
A natural-circulation type phase-change cooling system has been known as an example of efficient cooling systems for electronic devices and the like (see, Patent Literature 1, for example). In the natural-circulation type phase-change cooling system, the heat generated by a heat source such as an electronic device is received and released using the latent heat of refrigerant. This system makes it possible to drive the refrigerant circularly without power supply because of the buoyancy of refrigerant vapor and the gravity of refrigerant liquid. Accordingly, the natural-circulation type phase-change cooling system enables efficient and energy-saving cooling of electronic devices and the like.
An example of a natural-circulation type phase-change cooling device is described in Patent Literature 1. A related cooling system disclosed in Patent Literature 1 includes evaporators set respectively in a plurality of servers, a cooling tower installed on the roof of a building, a return pipe (refrigerant gas pipe), and a supply pipe (refrigerant liquid pipe). The return pipe and the supply pipe connect cooling coils set in the evaporators to a spiral pipe set in the cooling tower. The return pipe returns the refrigerant gas vaporized in the evaporators to the cooling tower. The supply pipe supplies the evaporators with the refrigerant liquid that is liquefied resulting from cooling and condensing the refrigerant gas in the cooling tower. This forms a circulation line through which the refrigerant circulates naturally, between the evaporators and the cooling tower.
Each evaporator is provided with a temperature sensor to measure the temperature of the air that results from cooling, in the evaporator, the high temperature air exhausted from a server. At the outlet of the cooling coil in each of the evaporators, a valve (flow adjustment means) is provided that adjusts the supply flow rate of the refrigerant supplied to the cooling coil (refrigerant flow). A controller automatically adjusts the degree of opening of each valve based on the temperature measured by the temperature sensor. This enables the supply flow rate of the refrigerant to decrease by narrowing the opening of the valve if the temperature of the air that has been cooled in the evaporators becomes too lower than a predetermined temperature.
It is said that, according to the related cooling system, the above-described configuration keeps the supply flow rate of the refrigerant in each evaporator from increasing more than necessary; accordingly, it is possible to reduce the cooling load of the refrigerant and achieve a sufficient cooling performance by using a cooling tower only.
[PTL 1] Japanese Unexamined Patent Application Publication No. 2009-194093 (paragraphs [0047]-[0055],
As mentioned above, the related cooling system disclosed in Patent Literature 1 is configured to include valves respectively to adjust the supply flow rate of the refrigerant supplied to the cooling coils that are disposed in the evaporators, and to adjust automatically the degree of opening of each valve based on the temperature of the air that has been cooled in the evaporators. That is to say, a computerized valve is disposed at the outlet of the evaporator and made to operate simultaneously with the temperature sensor, by which an appropriate amount of refrigerant liquid is supplied to the evaporator depending on the load of the server rack. The reason is that the phase change is inhibited due to the pressure of the refrigerant liquid if there is too much fluid volume of the refrigerant liquid in the evaporator, which results in conventional liquid cooling by sensible heat, not by latent heat with large amount of heat transfer. The reason is that it becomes difficult to perform the phase-change cooling efficiently because it is impossible to absorb the heat without the phase change arising if the fluid volume of the refrigerant liquid becomes insufficient in contrast.
However, because the related cooling system is configured to include a valve in each of the plurality of evaporators, there has been the problem that the related cooling system requires the cost not only of devices including a valve control system but also of the maintenance for stable operation.
Thus, there has been the problem that it is impossible to avoid the increase in device cost and maintenance cost in order to cool a heat source efficiently using a natural-circulation type phase-change cooling device.
The object of the present invention is to provide a cooling device and a method of manufacturing the cooling device that solve the above-mentioned problem that it is impossible to avoid the increase in device cost and maintenance cost in order to cool a heat source efficiently using a natural-circulation type phase-change cooling device.
A cooling device according to an exemplary aspect of the present invention includes a heat receiving unit for receiving heat; a condensing unit for releasing heat; and a refrigerant intermediary unit for connecting the heat receiving unit with the condensing unit, and transporting refrigerant circulating between the heat receiving unit and the condensing unit, wherein the refrigerant intermediary unit includes a refrigerant retaining unit for retaining the refrigerant, a primary tube connecting the refrigerant retaining unit with the condensing unit, and a secondary tube connecting the refrigerant retaining unit with the heat receiving unit and including a bendable tube.
A method of manufacturing a cooling device according to an exemplary aspect of the present invention includes disposing a heat receiving unit for receiving heat; disposing a condensing unit for releasing heat on a ceiling panel; disposing a refrigerant retaining unit for retaining refrigerant below the condensing unit and above the heat receiving unit; connecting the refrigerant retaining unit with the condensing unit by a primary tube; and connecting the refrigerant retaining unit with the heat receiving unit by a secondary tube including a bendable tube.
According to the cooling device and the method of manufacturing the cooling device of the present invention, it is possible to cool a heat source efficiently employing a natural-circulation type phase-change cooling system without the increase in device cost and maintenance cost.
Example embodiments of the present invention will be described with reference to drawings below.
The heat receiving unit 1010 contains refrigerant to receive heat from a heat source. The condensing unit 1020 condenses and liquefies refrigerant vapor of the refrigerant evaporated in the heat receiving unit 1010 and generates refrigerant liquid.
The refrigerant transporting structure (refrigerant intermediary unit) connects the heat receiving unit 1010 with the condensing unit 1020, and transports the refrigerant circulating between the heat receiving unit 1010 and the condensing unit 1020. More specifically, the refrigerant transporting structure transports and conveys the refrigerant evaporated in the heat receiving unit 1010 (refrigerant vapor) and the refrigerant condensed and liquefied in the condensing unit 1020 (refrigerant liquid), in the course of circulating between the heat receiving unit 1010 and the condensing unit 1020. The refrigerant transporting structure includes a refrigerant retaining unit 1300 for retaining the refrigerant, a primary tube 1110 connecting the refrigerant retaining unit 1300 with the condensing unit 1020, and a secondary tube 1120 connecting the refrigerant retaining unit 1300 with the heat receiving unit 1010 and including a bendable tube (flexible tube). As illustrated in
A part of the secondary tube (secondary liquid tube) 1120 is a bendable flexible tube 1122. The flexible tube 1122 connects the refrigerant liquid reservoir 1301 with the heat receiving unit 1010 in the electronic equipment rack 1011 by means of flanges 1121 and the like. The flexible tube 1122 can be disposed on a plane, for example, on a plane approximately level to the top board surface of the electronic equipment rack 1011. This arrangement frees the flexible tube 1122 from a twist around the rotation axis indicated by the dashed arrow in
The flexible tube 1122 can be configured such that the end portion of the flexible tube 1122 on the side where the secondary tube 1120 is connected with the refrigerant liquid reservoir 1301 is located above the other end portion of the flexible tube 1122 on the side where the secondary tube 1120 is connected with the heat receiving unit 1010. Sloping the secondary tube 1120 as described above facilitates the natural circulation of the refrigerant liquid by the effect of the force of gravity.
In
The above description has been made with respect to the configuration of the phase-change cooling device 1000 that includes single heat receiving unit 1010. Alternatively, as illustrated in
In the above description, the refrigerant retaining unit 1300 has been described as the refrigerant liquid reservoir 1301 to store the refrigerant liquid. Alternatively, the refrigerant retaining unit may be a vapor convergence unit in which the streams of the refrigerant vapor converge. In this case, the primary tube is a primary vapor tube through which the refrigerant vapor mainly flows, and the secondary tube is a secondary vapor tube through which the refrigerant vapor mainly flows.
Next, a method of manufacturing the phase-change cooling device according to the present example embodiment will be described.
In the method of manufacturing the phase-change cooling device according to the present example embodiment, first, a heat receiving unit configured to receive heat from a heat source and contain refrigerant is disposed, and a condensing unit configured to condense and liquefy refrigerant vapor of the refrigerant evaporated in the heat receiving unit and generate refrigerant liquid is disposed on the ceiling panel. A refrigerant retaining unit configured to retain the refrigerant is disposed below the condensing unit and above the heat receiving unit. The refrigerant retaining unit is connected with the condensing unit by a primary tube, and the refrigerant retaining unit is connected with the heat receiving unit by a secondary tube including a bendable flexible tube. Through the above processes, the phase-change cooling device according to the present example embodiment has been completed.
As mentioned above, the phase-change cooling device 1000 according to the present example embodiment is configured to include a refrigerant transporting structure connecting the heat receiving unit 1010 with the condensing unit 1020, the refrigerant transporting structure including the refrigerant retaining unit 1300 and the secondary tube 1120 including a flexible tube.
The refrigerant vapor evaporated by receiving heat in the heat receiving unit 1010 is condensed and liquefied in the condensing unit 1020 into refrigerant liquid and flows back to the heat receiving unit 1010. Because the refrigerant retaining unit 1300 stores the refrigerant temporarily, it can compensate for the excess or deficiency of the refrigerant flowing back to the heat receiving unit 1010. Consequently, according to the phase-change cooling device of the present example embodiment, it is possible to cool a heat source efficiently employing a natural-circulation type phase-change cooling system without the increase in device cost and maintenance cost. In addition, because the phase-change cooling device 1000 according to the present example embodiment is configured to include the flexible tube, it is possible to increase the degree of freedom in installing the phase-change cooling device 1000; for example, it becomes possible to load the heat receiving unit in moving parts of the electronic equipment rack.
Next, a second example embodiment of the present invention will be described.
The phase-change cooling device 2000 according to the present example embodiment differs from the phase-change cooling device 1000 according to the first example embodiment in including a plurality of heat receiving units 1010, and including a refrigerant liquid reservoir 2301 configured to store refrigerant liquid and a vapor convergence unit 2302 in which streams of refrigerant vapor converge that serve as a refrigerant retaining unit. As illustrated in
The configuration of the phase-change cooling device 2000 according to the present example embodiment will be described further in detail. The phase-change cooling device 2000 according to the present example embodiment includes a plurality of heat receiving units 1010, a condensing unit 1020, and a refrigerant transporting structure connecting the heat receiving units 1010 with the condensing unit 1020. The refrigerant transporting structure includes a refrigerant liquid transporting structure 2100 configured to transport refrigerant liquid and a refrigerant vapor transporting structure 2200 configured to transport refrigerant vapor.
The refrigerant liquid transporting structure 2100 includes a refrigerant liquid reservoir 2301, a primary liquid tube 2110 connecting the refrigerant liquid reservoir 2301 with the condensing unit 1020, and a secondary liquid tube 2120 connecting the refrigerant liquid reservoir 2301 with each of the plurality of heat receiving units 1010 and including a bendable flexible tube. In the primary liquid tube 2110 and the secondary liquid tube 2120 flows mainly refrigerant liquid.
The refrigerant vapor transporting structure 2200 includes a vapor convergence unit 2302, a primary vapor tube 2210 connecting the vapor convergence unit 2302 with the condensing unit 1020, and a secondary vapor tube 2220 connecting the vapor convergence unit 2302 with each of the plurality of heat receiving units 1010 and including a bendable flexible tube. In the primary vapor tube 2210 and the secondary vapor tubes 2220 flows mainly refrigerant vapor.
Because the refrigerant liquid pools in the refrigerant liquid reservoir 2301, the refrigerant liquid is supplied from the refrigerant liquid reservoir 2301 to each of the heat receiving units 1010 in just proportion depending on the amount of the refrigerant liquid having decreased due to vaporization by receiving heat in each of the heat receiving units 1010. That is to say, it becomes possible to supply the refrigerant liquid with the quantity corresponding to the load of each heat receiving unit 1010 to each of the heat receiving units 1010 without using driving parts, sensing components, and the like.
Because the streams of the refrigerant vapor generated in the plurality of heat receiving units 1010 are converged in the vapor convergence unit 2302, it is possible to decrease the pressure loss due to branching. As a result, it is possible to achieve an efficient cooling by the natural-circulation type phase-change cooling system without degrading the cooling performance, even though the plurality of heat receiving units 1010 are included.
As mentioned above, the phase-change cooling device 2000 according to the present example embodiment is configured to include the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302. This makes it possible to cool a heat source efficiently employing a natural-circulation type phase-change cooling system without the increase in device cost and maintenance cost. In addition, the phase-change cooling device 2000 according to the present example embodiment is configured to include the secondary liquid tubes 2120 and the secondary vapor tubes 2220 that include the flexible tubes. This makes it possible to increase the degree of freedom in installing the phase-change cooling device 2000; for example, it becomes possible to load the heat receiving unit in moving parts of the electronic equipment rack.
Next, a specific configuration of the phase-change cooling device 2000 according to the present example embodiment will be described.
The heat receiving unit 1010 includes a plurality of evaporators thermally connected with heat sources and storing refrigerant, and constitutes a cooling unit in which the plurality of evaporators are disposed in a vertical direction. The cooling unit that serves as the heat receiving unit 1010 is loaded onto the rear door of the electronic equipment rack 1011. In addition, as illustrated in
More specifically, the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302 can be mounted on the top board of the electronic equipment rack 1011 using an attaching structure 2410. The refrigerant liquid reservoir 2301 and the vapor convergence unit 2302 are connected with the plurality of heat receiving units 1010 loaded in the plurality of electronic equipment racks 1011 by means of the secondary liquid tubes 2120 and the secondary vapor tubes 2220, respectively. The configuration makes it possible to use mechanism elements such as a screw hole included in the electronic equipment rack 1011. This makes it possible to mount easily the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302 with the electronic equipment racks 1011 having already been installed. Alternatively, the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302 may be disposed above the electronic equipment racks 1011 by fixing them to the ceiling panel 2001 using a ceiling-suspended structure or the like.
As illustrated in
In this case, switching mechanisms such as a valve can be provided for connecting ports that are connected with the secondary liquid tubes 2120 and the secondary vapor tubes 2220 and included in the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302 respectively. This eliminates the need for connecting the electronic equipment racks 1011 to all the connection ports, which enables the maintenance and replacement of the electronic equipment rack 1011.
In the above description, the phase-change cooling device 2000 is configured to have the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302 that serve as the refrigerant retaining units disposed above the plurality of electronic equipment racks 1011. Alternatively, as illustrated in
The combined refrigerant retaining unit 2303 retains both the refrigerant vapor and the refrigerant liquid, and mixed refrigerant liquid that is liquid-state refrigerant mixed in the refrigerant vapor flows out from the combined refrigerant retaining unit 2303 to the secondary liquid tubes 2120 together with the refrigerant liquid. This enables the mixed refrigerant liquid to be removed from the refrigerant vapor; therefore, it is possible to prevent an increase in fluid resistance to the refrigerant vapor that causes the degradation of the cooling performance.
Next, a third example embodiment of the present invention will be described.
The phase-change cooling device 3000 according to the present example embodiment includes a plurality of heat receiving units 1010, the refrigerant liquid reservoir 2301 configured to store the refrigerant liquid and the vapor convergence unit 2302 in which streams of the refrigerant vapor converge that serve as the refrigerant retaining units.
The heat receiving unit 1010 includes a plurality of evaporators thermally connected with heat sources and storing refrigerant, and constitutes a cooling unit in which the plurality of evaporators are disposed in a vertical direction. The cooling unit that serves as the heat receiving unit 1010 is loaded on the rear door of the electronic equipment rack 1011.
The above-described configuration is similar to that of the phase-change cooling device 2000 according to the second example embodiment. In the phase-change cooling device 3000 according to the present example embodiment, a plurality of electronic equipment racks 1011 are arranged so as to face each other across an inter-rack aisle 3100. The refrigerant liquid reservoir 2301 and the vapor convergence unit 2302 that serve as the refrigerant retaining units are disposed above the inter-rack aisle 3100. The inter-rack aisle 3100 includes an aisle through which the cooling air introduced from the front of the electronic equipment rack 1011 flows (a cold aisle) and an aisle through which the air with waste heat exhausted from the back side of the electronic equipment rack 1011 flows (a hot aisle).
More specifically, as illustrated in
As mentioned above, the phase-change cooling device 3000 according to the present example embodiment is configured to include the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302. This makes it possible to cool a heat source efficiently employing a natural-circulation type phase-change cooling system without the increase in device cost and maintenance cost. In addition, the phase-change cooling device 3000 according to the present example embodiment is configured to include the secondary liquid tubes 2120 and the secondary vapor tubes 2220 that include the flexible tubes. This makes it possible to increase the degree of freedom in installing the phase-change cooling device 3000; for example, it becomes possible to load the heat receiving unit in moving parts of the electronic equipment rack.
The partition wall 3310 includes an aisle capping or the like that is provided for the cold aisle or the hot aisle in order to prevent the cooling air introduced from the front of the electronic equipment rack 1011 from mixing with the warm air exhausted from the exhaust side of the electronic equipment racks 1011, for example. Since the aisle capping is configured to cover with a curtain made of vinyl or the like by the support pole 3320, it is possible to attach the top board 3330 to the support pole 3320 together with the curtain. This makes it possible to maintain strength to support the refrigerant liquid reservoir 2301 and the vapor convergence unit 2302.
The configuration makes it possible to achieve an efficient air flow in the building by means of the partition wall 3310 and promote efficient heat exhaust by using the phase-change cooling system. The synergistic effect of these advantages makes it possible to reduce drastically the power consumption for air conditioning of the building in which the electronic equipment rack 1011 is installed.
Hereinabove, the present invention has been described using the above-described example embodiments as exemplary examples. The present invention, however, is not limited to the above-described example embodiments. In other words, various aspects that can be recognized by those skilled in the art can be applied to the present invention within the scope of the invention.
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-196175, filed on Sep. 26, 2014, the disclosure of which is incorporated herein in its entirety by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-196175 | Sep 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/004700 | 9/15/2015 | WO | 00 |
