AU767843B2

AU767843B2 - System and method for temperature management in an electronic enclosure

Info

Publication number: AU767843B2
Application number: AU95145/01A
Authority: AU
Inventors: Jake J Han
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2000-11-28
Filing date: 2001-11-28
Publication date: 2003-11-27
Anticipated expiration: 2021-11-28
Also published as: AU9514501A; KR20020041734A; CN1356866A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): SAMSUNG ELECTRONICS CO., LTD.

Invention Title: SYSTEM AND METHOD FOR TEMPERATURE MANAGEMENT IN AN ELECTRONIC ENCLOSURE The following statement is a full description of this invention, including the best method of performing it known to me/us: SYSTEM AND METHOD FOR TEMPERATURE MANAGEMENT IN AN ELECTRONIC ENCLOSURE TECHNICAL FIELD OF THE INVENTION The present invention is directed, in general, to a telecommunications electronics enclosure and, more specifically, to a system for controlling temperature within the electronics enclosure.

BACKGROUND OF THE INVENTION o Wireless telecommunications systems often require high power ooooo electronics that are generally enclosed in a weather resistant is outdoor electronic cabinet which may be deployed remotely. Such a unit may be a base transceiver station (BTS) for a wireless communication network, such as a code division multiple access (CDMA) wireless network. A BTS includes different electronic modules that generate heat, including: power distribution panel, transmission 20 control unit, power amplifiers, etc. The power amplifiers usually generate quite a bit of heat. Even though the other electronic modules generate heat the power amplifiers are the major contributors to heat 1N rise in the BTS cabinet.

Forced air cooling is usually required in the BTS cabinet for warm weather operation to maintain an acceptable operating temperature. Since a power amplifier typically generates more heat than the other electronic modules, a heat sink is usually used in combination with ambient, forced air to cool the amplifier. Dust, debris, moisture and other contaminants accompany incoming ambient air and accumulate on the amplifier housing and heat sink. The accumulations reduce the efficiency of the forced air cooling and the heat sink. The fan that pulls the air, dust, debris and moisture into the cabinet, also generates electrical and mechanical noise that can c interfere with BTS operation. Even if filters are used, the filters S"require cleaning and maintenance and usually dust and moisture gets through the filter and fouls the equipment.

There is therefore a need in the art for a heat management system that will provide cooling for high heat generating devices in an enclosure. There is a further need for preventing dust and debris -fee.:.

r accumulations on electronic devices and controlling the temperature within the enclosure.

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S 2 3 SUMMARY OF THE INVENTION According to one aspect of the present invention, there is provided for use with a base station in a wireless network, a heat management system for controlling heat in one of said base stations, comprising: a cabinet comprising a plurality of heat generating modules; an air-to-air heat exchanger thermally coupled to said cabinet; and a liquid-to-air heat exchanger thermally coupled to said air-to-air heat exchanger and to at least one of said heat generating modules.

According to a further aspect of the present invention, there is provided a base transceiver station for transmitting and receiving wireless communications in a wireless communications network comprising: an electronics enclosure for said base transceiver station electronic and power components; and a heat management system for controlling heat in said electronics enclosure comprising: a cabinet comprising a plurality of heat generating modules; an air-to-air heat exchanger thermally coupled to said cabinet; and a liquid-to-air heat exchanger thermally coupled to V said air-to-air heat exchanger and to at least one of said heat generating modules.

According to a further aspect of the present invention, there is provided for use with a base station in a wireless network, a method of controlling heat in one of said base stations, comprising the steps of: H: \jolzik\keep\Speci\Samsung\95145-01.doc 07/10/03 4 thermally and mechanically coupling an air-to-air heat exchanger to a base station cabinet comprising a plurality of heat generating modules; and thermally coupling a liquid-to-air heat exchanger to said air-to-air heat exchanger and to at least one of said plurality of said heat generating modules.

According to a further aspect of the present invention, there is provided a wireless communications network comprising a plurality of base transceiver stations.

The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention

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in its broadest form.

Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation; the term is inclusive, meaning and/or; the phrases "associated with" and "associated therewith," as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, ooooo: io couple to or with, be communicable with, cooperate with, interleave, .juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term "controller" means any device, system or ooooo part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination eoeee 15 of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like numbers designate like objects, and in which: FIGURE 1A illustrates an exemplary block diagram of a telecommunications network according to one embodiment of the present invention; oooo FIGURE lB depicts, in greater detail, abase transceiver station in the exemplary block diagram according to one embodiment of the present invention; -FIGURE 2 illustrates a block diagram of a heat management system coupled to a base transceiver station cabinet according to one 15 embodiment of the present invention; and FIGURE 3 depicts a high-level block diagram of a low power amplifier and heat transfer plate according to an embodiment of the present invention.

FIGURE 4 is a flow diagram illustrating the operation of the exemplary heat management system according to one embodiment of the present invention.

6 DETAILED DESCRIPTION OF THE INVENTION FIGURES 1 through 4, discussed below, and the various embodiments used to describe the principles of the present invention s in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any suitably arranged heat management system.

ooooo FIGURE 1A illustrates a general overview of exemplary wireless network 100 according to an embodiment of the present invention.

Wireless network 100 comprises a plurality of cell sites 121-123, eeooe2 each containing one of the base stations, BS 101, BS 102, or BS 103.

Base stations 101-103 are operable to communicate with a plurality ooooo 15is of mobile stations (MS) 111-114. Mobile stations 111-114 may be any suitable wireless communication devices, including conventional cellular telephones, PCS handset devices, portable computers, telemetry devices, and the like.

Dotted lines show the approximate boundaries of the cell sites 121-123 in which base stations 101-103 are located. The cell sites are shown approximately circular for the purposes of illustration and explanation only. It should be clearly understood 7 that the cell sites also may have irregular shapes, depending on the cell configuration selected and both natural and man-made obstructions.

In one embodiment of the present invention, BS 101, BS 102, and BS 103 each may comprise a base station controller (BSC) and a base transceiver station (BTS). Base station controllers and base transceiver stations are well known to those skilled in the art.

base station controller is a device that manages wireless communications resources, including the base transceiver station, ooooo for specified cells within a wireless communications network. Abase transceiver station comprises the RF transceivers, antennas, and other electrical equipment located in each cell site. This equipment Smay include air conditioning units, heating units, electrical supplies, telephone line interfaces, and RF transmitters and RF oeooe 15 receivers, as well as call processing circuitry. For the purpose of simplicity and clarity in explaining the operation of the present invention, the base transceiver station in each of cells 121, 122, and 123 and the base station controller associated with each base transceiver station are collectively represented by BS 101, BS 102 and BS 103, respectively.

BS 101, BS 102 and BS 103 transfer voice and data signals between each other and the public telephone system (not shown) via 8 communications line 131 and mobile switching center (MSC) 140.

Mobile switching center 140 is well known to those skilled in the art.

Mobile switching center 140 is a switching device that provides services and coordination between the subscribers in a wireless network and external networks, such as the public telephone system and/or the Internet. Communications line 131 may be any suitable connection means, including a T1 line, a T3 line, a fiber optic link, a network backbone connection, and the like. In some embodiments of :the present invention, communications line 131 may be several 10 different data links, where each data link couples one of BS 101, BS 102, or BS 103 to MSC 140.

In the exemplary wireless network 100, MS 111 is located in cell site 121 and is in communication with BS 101, MS 113 is located in cell site 122 and is in communication with BS 102, and MS 114 is 15 located in cell site 123 and is in communication with BS 103. MS 112 o o. is also located in cell site 121, close to the edge of cell site 123.

0 a The direction arrow proximate MS 112 indicates the movement of MS 112 towards cell site 123. At some point, as MS 112 moves into cell site 123 and out of cell site 121, a "handoff" will occur.

As is well known, the "handoff" procedure transfers control of a call from a first cell to a second cell. For example, if MS 112 is in communication with BS 101 and senses that the signal from BS 101 is 9

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becoming unacceptably weak, MS 112 may then switch to a BS that has a stronger signal, such as the signal transmitted byBS 103. MS 112 and BS 103 establish a new communication link and a signal is sent to BS 101 and the public telephone network to transfer the on-going voice, data, or control signals through BS 103. The call is thereby seamlessly transferred from BS 101 to BS 103. An "idle" handoff is a handoff between cells of a mobile device that is communicating in the control or paging channel, rather than transmitting voice and/or data signals in the regular traffic channels.

ooooe 10 FIGURE lB depicts, in greater detail, exemplary base station 101 in accordance with one embodiment of the present invention. Base station 101 comprises base station controller (not ooooo *shown) and base transceiver station (BTS) 150. Base station controllers and base transceiver stations were described previously oeooe 15 in connection with FIGURE 1. As described above, BTS 150 includes electronics modules such as RF transceivers, antennas, RF transmitters and RF receivers. Most of the electronics modules are contained in outdoor electronic cabinet 152. Cabinet 152 is required to protect the electronics modules against the environment and to maintain an internal operating temperature within a specified range.

MS 111 transmits and receives from antenna 154 and the signals may be sent to MSC 140 and on to the public service telephone network 10 (not shown) via communications line 131.

FIGURE 2 illustrates, in greater detail, a high-level block diagram of a heat management system coupled to a base transceiver cabinet, according to one embodiment of the present invention.

Electronics cabinet 152 includes electronics modules described in FIGURE lA-lB. Some of the specific modules include front end unit (FEU) 230, transmission control unit 232, channel cards (CEB) 234 and power distribution panel 236. Additionally, power amplifiers are included within the cabinet and are represented by low power amplifier ooooo o 10 (LPA) 245. Power amplifiers are generally the largest heat generators in BTS cabinet 152. Heat is a major problem with the electronics modules and external temperature control systems are utilized to control the temperature within cabinet 152.

Air flow within cabinet 152 is depicted by arrow 240 and arrow 225.

ooooo 15 Arrow 225 illustrates air flow that has passed over electronics modules 230-238 absorbing heat generated by the modules. Air

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circulates through plenum 215 of heat management system 205, in a closed loop, so as to limit ambient air and the accompanying contaminants from entering cabinet 152. Fan 207 provides forced air circulation through plenum 215. Hot air 225 is forced through plenum 215 and recuperator 222. Recuperator 222 is a heat transfer device that provides (in this instance) two fluid (in this instance air) flow 11 paths; one for the outside air flow and one for the inside air flow.

As heated inside air flows through plenum 215, outside cooler air 220 flows through plenum 210 and the second air flow path through recuperator 222. Heat transfer is accomplished by outside air 220 absorbing heat from inside air 225 via recuperator 222 by conduction.

Outside air 220 is forced through plenum 210, through the outside air path in recuperator 222 and exhausted as heated outside air 265.

At the same time, inside air 225, having passed through plenum 215 and recuperator 222, becomes cooled air 240 as a result of transferring a 10 heat via recuperator 222 to outside air 220.

Inside air 240, now cooled, passes over electronic modules and repeats the cycle. Heat generated by the amplifiers in cabinet 152 is a .considerably higher than the cumulative heat generated by the other electronic modules, including modules 230-238. Consequently, the 15 temperature of the air passing over the other electronic modules is already increased. Heat management system 205 utilizes a separate liquid-to-air heat exchanger (heat exchange plate) 250 for cooling LPA 245.

Heat exchange plate 250 is mechanically and thermally coupled to LPA 245. Low temperature liquid 255 is circulated through heat exchange plate 250 and heat is transferred from LPA 245 via heat exchange plate 250 to low temperature liquid 255. High temperature 12 liquid 260, having received heat from heat exchange plate 250, is exhausted and circulates through a liquid-to-air heat exchanger 263 in the outer loop 210 exhaust 265. Even though the air being passed from plenum 215 is already a higher temperature than the air at intake 220, the liquid-to-air heat exchanger 263 is at a much higher temperature Heat transfer takes place from liquid-to-air heat exchanger 263 to outer loop exhaust 265.

FIGURE 3 depicts a high-level block diagram of a low power fee amplifier and heat transfer plate according to an embodiment of the f 0 io present invention. Electronics cabinet 152 is illustrated with only the power amplifier portion showing, for clarity and to more clearly explain the function of liquid-to-air heat exchanger 263. Generally, r o •electronic modules other than power amplifiers are located in a different section of electronics cabinet 152 because of the different OS e g 15 cooling requirements. The power amplifiers may be located in the bottom section of electronics cabinet 152 to receive the coolest air.

go 0..S* In this embodiment, LPA 245 is mechanically and thermally coupled to heat exchange plate 250. Temperature controller 320 senses the temperature in the cabinet and operates a pump (not shown) to begin circulation of liquid as a predetermined temperature is reached.

Valve 325 controls the input of liquid to heat transfer plate 250 13 through supply line 305 based on the sensed temperature. As shown in Front View, liquid flows into liquid intake 305 and circulates through heat exchange plate 250 via embedded conduit 310. Heat exchange plate 250 extracts heat from LPA 245 and transfers that heat to the liquid flowing through embedded conduit 310. The heat is rejected from cabinet 152 by transporting the high temperature liquid to liquidto-air heat exchanger 263 in the heat management system 205.

FIGURE 4 depicts a high-level flow diagram 300, which illustrates the operation of the exemplary temperature management o o 10 system according to one embodiment of the present invention. The

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process begins when the temperature in the interior of the BTS cabinet rises to an upper, predetermined limit (process step 400) The heat oooee management system senses the temperature and activates the system (process step 402). Next, the fans governing the air flow in the inner S 15 and outer air flow loops are turned on (process step 404) IOO o The outer air flow loop intakes lower temperature ambient air and begins circulating through the outside plenum. The inner air flow loop begins circulating the air, in a closed loop, from inside the cabinet through the inside plenum through the recuperator. Heat is transferred from the inner air flow to the outer air flow via the recuperator (process step 406) After a period of time the power amplifiers begin to generate 14 more heat, due to their operating characteristics (process step 408) As the power amplifiers reach an upper temperature limit, the heat management system sends a signal to the temperature controller to start liquid flow through the heat transfer plate that is connected to the power amplifiers (process step 410). The outer air flow loop includes the liquid-to-air heat exchanger and the air flow is routed through the heat exchanger regularly. However, when the temperature sensed at the power amplifiers reaches a predetermined limit, the liquid flow begins and the outer flow air drops the temperature of the io liquid (process step 412) Heat is transferred to the cooled liquid from the heat exchange plate that is thermally and mechanically coupled to a power amplifier.

ooooo The liquid is pumped from the heat exchange plate to the liquidto-air heat exchanger, where the lower temperature outside air loop eeeoe 15 transfers heat in the liquid to the outside air (process step 414) eeee.

Though the power amplifiers are in the same cabinet as the other electronic modules, the liquid-to-air heat exchange plate transfers heat energy from the power amplifiers to the outside air via the liquid flow through the liquid-to-air heat exchanger. This action reduces the contribution of heat to the cabinet interior by the power amplifiers.

Although the present invention has been described in detail, 15 those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.

For the purposes of this specification it will be clearly understood that the word "comprising" means "including but not limited to", and that the word "comprises" has a corresponding meaning.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

e.e e *ee.

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Claims

7. The heat management system as set forth in claim 6, further comprising a temperature controller for controlling liquid flow through said heat transfer plate.
8. A base transceiver station for transmitting and receiving wireless communications in a wireless communications network comprising: an electronics enclosure for said base transceiver station electronic and power components; and a heat management system for controlling heat in said electronics enclosure comprising: a cabinet comprising a plurality of heat generating modules; an air-to-air heat exchanger thermally coupled to said cabinet; and a liquid-to-air heat exchanger thermally coupled to said air-to-air heat exchanger and to at least one of said heat generating modules. o H: \jolzik\keep\Speci\Sarsung\95145-O.doc 07/10/03 20
9. The base transceiver station as set forth in claim 8 wherein said air to air heat exchanger, further comprises: an inner air flow loop for transferring heat to a recuperator from said heat generating modules; and an outer air flow loop for transferring heat from said recuperator to ambient air. The base transceiver station as set forth in claim 9 wherein said liquid to air heat exchanger is thermally connected to the exhaust of said outer air flow loop for transferring heat from said at least one of said high heat generating modules.
11. The base transceiver station as set forth in claim 8 wherein said heat management system further comprises: a heat transfer plate comprising mounting hardware for mechanically and thermally coupling said heat transfer plate to said at least one of said high heat generating modules. :20 12. The base transceiver station as set forth in claim 11 S wherein said heat management system further comprises: a continuous conduit embedded in said heat transfer plate, with an intake and an exhaust, for circulating a liquid. H:\jolzik\keep\Speci\Samsung\95145-Ol.doc 07/10/03 21
13. The base transceiver station as set forth in claim 12 wherein said heat management system further comprises a temperature controller for controlling liquid flow to said heat transfer plate.
14. The base transceiver station as set forth in claim 13 wherein said heat management system further comprises: a liquid-to-air recuperator for transferring heat from said liquid to the exhaust of said air-to-air heat exchanger. For use with a base station in a wireless network, a method of controlling heat in one of said base stations, comprising the steps of: thermally and mechanically coupling an air-to-air heat exchanger to a base station cabinet comprising a plurality of heat generating modules; and thermally coupling a liquid-to-air heat exchanger to said air-to-air heat exchanger and to at least one of said :i20 plurality of said heat generating modules. *S e oo o o .00 H:\jolzik\keep\Speci\Samsung\95145-01.doc 07/10/03 1 16. The method for controlling heat as set forth in Claim 2 wherein said air-to-air heat exchanger, further comprises the steps 3 of: 4 transferring heat to a recuperator from said heat generating modules via an inner air flow loop; and 6 transferring heat from said recuperator to ambient air via 7 an outer air flow loop for. 1 17. The method for controlling heat as set forth in Claim 16, 2 further comprising the step of transferring heat from said at least 3 one of said high heat generating modules, wherein said liquid-to-air 4 heat exchanger is thermally connected to the exhaust of said outer air 5 flow loop. 1 18. The method for controlling heat as set forth in Claim 2 further comprising the step of coupling said heat transfer plate, 3 mechanically and thermally, to said at least one of said high heat S.. 4 generating modules. ee 1 19. The method for controlling heat as set forth in Claim 2 further comprising the step of circulating a liquid through a 3 continuous conduit, with an intake and an exhaust, embedded in said 4 heat transfer plate. 22 23 The method for controlling heat as set forth in claim further comprising the step of controlling liquid flow to said heat transfer plate utilizing a temperature controller.
21. The method for controlling heat as set forth in claim further comprising the step of transferring heat from said liquid to the exhaust of said air-to-air heat exchanger utilizing a liquid-to-air recuperator.
22. A wireless communications network comprising a plurality of base transceiver stations as claimed in claim 8.
23. A heat management system as claimed in any one of claims 1 to 7, and substantially as herein described with reference to the accompanying drawings.
24. A base transceiver station as claimed in any one of claims 8 to 14, and substantially as herein described with reference to the accompanying drawings.
25. A method as claimed in any one of claims 15 to 21, and substantially as herein described with reference to the accompanying drawings.
26. A wireless communications network as claimed in claim 22, and substantially as herein described with reference to the accompanying drawings. Dated this 7th day of October 2003 39 SAMSUNG ELECTRONICS CO., LTD By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia H:\jolzik\keep\Speci\Samsung\95145-01.doc 07/10/03