Created: 10/24/95 Updated: 8/18/98

Application of Phase Change Materials to Thermal Control of Electronic Modules

Project Number : C95-15

Point of Contact:
Dr. Yogi Joshi
CALCE EPRC
email: yogi@calce.umd.edu
Phone: (301) 405-5428
Fax: (301) 314-9269
Objectives Background Work Accomplised

Objectives

 

Background

Computational results from the past year of research have demonstrated the potential of PCMs for passive cooling applications of SEM-E modules. An experimental investigation under controlled conditions is necessary in order to validate the model. There is also a need to determine suitable ways of incorporating the PCM in a variety of applications.
 
 

Work Accomplished

Experiments for horizontal configuration: Thermal performance tests for the SEM-E horizontal configuration for ten^M different power levels and two different PCM quantities were completed.
The experimental setup consisted of an Aluminum substrate of size representative of a standard electronic module (SEM-E) card, heated by a silicone rubber heater on one side. On the other side, a 14 mm thick Aluminum honeycomb filled with organic PCM n-Triacontane was attached. This assembly was contained within a plexiglass enclosure, which was kept insulated during the experiments. A constant power input was supplied to the heater and temperatures at various locations were recorded as a function of time by a data acquisition system. The experiments were carried out for various power levels ranging from a minimum of 15 W to a maximum of 60 W. The effect of PCM quantity on the thermal performance was also tested by reducing the PCM quantity by 50%, and repeating the experiments.

 Experiments for vertical configuration: For the vertical configuration, experiments were performed for various power levels, using only PCM, and also with Aluminum foams, saturated with PCM.
The test cell was a high aspect ratio enclosure fabricated using 1/4 inch thick lexan. One of the inner vertical wall has a nichrome foil heater mounted on it. The enclosure was filled with PCM (n-Triacontane). During the experiment, the enclosure was kept insulated. Experiments were done for the same power levels as for the horizontal configuration. The transparent Lexan construction also made it possible to view the process of melting. Images were recorded with a CCD camera, and were processed to obtain the instantaneous locations of solid-liquid interfaces. To study the effect of incorporating the PCM in a metallic foam, to augment it's thermal conductivity, tests were carried out with three different Aluminum foams saturated with PCM.

Computation: The computational model for PCM melting in a foam was developed, and tested against published data. Simulations of the present experiments using this model were carried out.
Computational models developed during the previous year, were augmented for computations of PCM saturated foam. This includes the effect of natural convection in the open spaces following melting. Numerical simulations were performed for various power levels, and with and without the effects of convection. These were compared with the experimental measurements.
 
 

Work Accomplished