A hybrid heat sink concept which combines passive and active cooling approaches is proposed. The hybrid heat sink is essentially a plate ﬁn heat sink with the tip immersed in a phase change material (PCM). The exposed area of the ﬁns dissipates heat during periods when high convective cooling is available. When the air cooling is reduced, the heat is absorbed by the PCM. The governing conservation equations are solved using a ﬁnite-volume method on orthogonal, rectangular grids. An enthalpy method is used for modeling the melting/re-solidiﬁcation phenomena. Results from the analysis elucidate the thermal performance of these hybrid heat sinks. The improved performance of the hybrid heat sink compared to a ﬁnned heat sink (without a PCM) under identical conditions, is quantiﬁed. In order to reduce the computational time and aid in prelimi- nary design, a one-dimensional ﬁn equation is formulated which accounts for the simultaneous convective heat transfer from the ﬁnned surface and melting of the PCM at the tip. The inﬂuence of the location, amount, and type of PCM, as well as the ﬁn thickness on the thermal performance of the hybrid heat sink is investigated. Simple guidelines are developed for preliminary design of these heat sinks.
Electronics cooling, hybrid heat sinks, melting, phase change materials (PCMs), transient power dissipation
Date of this Version
S. Krishnan, S. V. Garimella, and S. S. Kang, “A Novel Hybrid Heat Sink using Phase Change Materials for Transient Thermal Management of Electronics,” IEEE Transactions on Components and Packaging Technologies, Vol. 28, No. 2, pp. 281-289, 2005.