Packaging system for thermally controlling the temperature of electronic equipment

• US 6,104,611 A
• Filed: 10/04/1996
• Issued: 08/15/2000
• Est. Priority Date: 10/05/1995
• Status: Expired due to Term

• Current Assignee: Ciena Corporation
• Original Assignee: Nortel Networks Corporation
• Inventors: Tencer, Michal Stefan, Bishop, Michael Reginald, Glover, Richard John
• Primary Examiner(s): TOLIN, GERALD P
• Application Number:
  US08/725,778
• Time in Patent Office: 1,411 Days
• Field of Search: 361/688, 361/698-700, 361/703, 361/704, 361/707, 361/708, 361/717-719, 174/15.2, 174/16.3, 174/252, 257/712-715, 165/104.21, 165/104.27, 165/104.33, 165/80.2, 165/80.3, 165/80.4, 165/80.5, 165/185, 165/10, 165/104.14
• US Class Current: 361/700
• CPC Class Codes: F28D 15/0275 Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
• CPC Class Codes: F28D 15/06 Control arrangements therefor
• CPC Class Codes: F28D 20/02 using latent heat
• CPC Class Codes: H05K 7/20336 Heat pipes, e.g. wicks or capillary pumps
• CPC Class Codes: Y02E 60/14 Thermal energy storage

Abstract

A passive method and packaging system for thermally controlling the temperature of electronic equipment within a housing are disclosed. The packaging system provides for two cooling steps, each of which uses a different passive cooling technology. Cooling by changing the phase of Phase Change Material, assists in controlling internal ambient temperatures by limiting the effects of short term localized thermal phenomena which would otherwise further increase internal temperatures. Cooling is also provided for by switching on a second passive cooling means, preferably a heat pipe, as the internal temperature of the housing increases above a predetermined temperature and to switch it off as the internal temperature drops below the predetermined temperature. Turning the second passive cooling means on and off provides respectively, a low or high thermal resistance path between the interior and exterior of the housing. The second passive cooling means allows for cooling of the housing above the predetermined temperature as well as heating of the housing below the predetermined temperature by preserving heat generated by the equipment. The two cooling steps in combination, co-operate to limit both maximum and minimum temperatures within the housing and of components. The combination of cooling steps also allows control over the temperature delta between the maximum and minimum temperatures during internal temperature swings.

Claims

1. A packaging system, comprising:

a substantially sealed and insulated housing;

support means disposed internally of the housing for supporting equipment;

first passive cooling means comprising phase change material disposed internal of the housing for absorbing heat above a first predetermined temperature thereby limiting further increases in temperature internal of the housing;

second passive cooling means comprising;

heat sink means disposed externally of the housing; and

passive switch means for providing a low thermal resistance path between the interior of the housing and the heat sink means above a second predetermined temperature to effect cooling of the equipment and for providing a high thermal resistance between the interior of the housing and the heat sink means below the second predetermined temperature to thereby preserve heat internal of the housing;

an electronic equipment supported by the support means, the electronic equipment having electrical components thermally conductively attached to a substrate, the substrate being thermally conductively attached to a thermally conductive member to form a module and wherein the module is removably thermally conductively attached to the switch means.

2. A packaging system as claimed in claim 1 wherein the phase change material is a paraffin wax.

3. A packaging system as claimed in claim 1 wherein the phase change material is thermally conductively attached to at least one interior wall surface.

4. A packaging system as claimed in claim 1 and further comprising a heat distributing structure disposed throughout the phase change material to more evenly subject the whole of the phase change material to local ambient temperatures.

5. A packaging system as claimed in claim 4 wherein the heat distributing structure comprises a metal substantially honey comb structure.

6. A packaging system as claimed in claim 5 wherein the metal is aluminum.

7. A packaging system as claimed in claim 4 wherein the heat distributing structure comprises a metal filamentary material substantially randomly disposed throughout the phase change material.

8. A packaging system as claimed in claim 1 wherein the heat sink means comprises a convection heat sink.

13. A packaging system as claimed in claim 1 or any one of claims 9-12 wherein the switch means includes a heat pipe.

14. A packaging system as claimed in claim 13 wherein the heat pipe is a variable conductance heat pipe.

15. A packaging system as claimed in claim 1 or 9 wherein the second predetermined temperature at which the switch means provides a low thermal resistance path is higher than the first predetermined temperature at which the phase change material starts to change phase.

9. A packaging system, comprising:

a substantially sealed and insulated housing;

support means disposed internally of the housing for supporting equipment;

first passive cooling means comprising phase change material disposed internal of the housing for absorbing heat above a first predetermined temperature, thereby limiting further increases in temperature internal of the housing;

second passive cooling means comprising;

heat sink means, disposed externally of the housing; and

passive switch means for providing a low thermal resistance path between the interior of the housing and the heat sink means above a second predetermined temperature to effect cooling of the equipment and for providing a high thermal resistance between the interior of the housing and the heat sink means below the second predetermined temperature to thereby preserve heat internal of the housing; and

a thermally conductive heat spreading means disposed internally of the housing and being thermally conductively attached to the switch means for efficiently passing heat internally of the housing to the switch means.

10. A packaging system as claimed in claim 9, further comprising electronic equipment having electrical components thermally conductively attached to a substrate, the substrate being thermally conductively attached to a thermally conductive member to form a module and wherein the module is removably thermally conductively attached to the heat spreading means.

11. A packaging system as claimed in claim 10, comprising a plurality of modules each of which is removably thermally conductively attached to the heat spreading means whereby individual module heat is combined and efficiently conducted to the switch means.

12. A packaging system as claimed in claim 10, wherein the phase change material is disposed adjacent the substrate and in thermal contact with the conductive member of the module to thereby be capable of limiting short term temperature increases local to the substrate.