THERMAL EVALUATION
ALUMINUM DESKTOP STAND
Submitted March 29, 2007
E.M. Gates, Professor Mechanical Engineering
W.C. Hauser, Professor Mechanical Engineering
California Polytechnic University at Pomona
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Executive Summary from LapWorks
This thermal study concluded that the Aluminum Desktop Stand reduces heat build-up by up to 23% by virtue of its heat-absorbing aluminum as well as the incline which allows heat to escape. As an example, a laptop placed on the Aluminum Desktop Stand on its steep, 37° incline that raises the screen by 6 inches ran 27 degrees cooler (88 compared to 115 degrees at maximum temperature) than the same laptop set flat on a desk.
Aluminum has a unique ability to absorb and then dissipate heat into the air. This is why most heatsinks which are attached to microprocessors to keep them from overheating are made of aluminum. The thinner the aluminum the better the absorption/dissipation process works.
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Title Page
Table of Contents
Computer Bottom Surface Thermal Maps
A. The computer resting on a flat rigid insulated surface to simulate a desk (Insulfoam, R = 4.17/inch) - Case 1.
B. Computer
resting on a soft
insulated surface, similar to a blanket - Case 2.
C. Computer
resting on the Aluminum Desktop Stand in its fully-collapsed position (0° incline) - Case 3.
D. Computer
resting on the Aluminum Desktop Stand at 21° - the short incline that raises the screen by 3 ½ inches - Case 4.
E. Computer
resting on the Aluminum Desktop Stand at 37° - the steep incline that raises the screen by 6 inches - Case 5.
Appendix 1. Thermocouple Locations and test data.
Appendix 2. Color map generation data.
The Aluminum Desktop Stand laptop computer support has been evaluated for effectiveness as a heat sink to reduce the bottom surface temperature of a Dell Inspiron 8000 laptop computer. The temperatures on the bottom surface of the computer were measured at twelve locations for five computer support cases with and without the Aluminum Desktop Stand.
Case 1. The computer resting on a flat rigid insulated surface to simulate a desk (Insulfoam, R = 4.17/inch).
Case 2. The computer resting on a folded cloth towel 1 inch thick to simulate the computer resting on a pillow or blanket - a common practice among laptop users when no table is available for support;
Case 3. Computer resting on the Aluminum Desktop Stand in its fully-collapsed position (0° incline).
Case 4. Computer resting on the Aluminum Desktop Stand at 21° - the short incline that raises the screen by 3 ½ inches.
Case 5. Computer resting on the Aluminum Desktop Stand at 37° - the steep incline that raises the screen by 6 inches.
The results of these measurements are summarized in Table I in which the average and peak surface temperatures of the computer bottom are summarized. In Figures 1 through 5 color maps and contours of constant temperature are plotted for the computer bottom surface.
Observations and Conclusions:
1. The effectiveness of the Aluminum Desktop Stand is influenced by the high thermal conductivity of the material from which the laptop is fabricated - aluminum. On an insulated flat surface (Cases 1 and 2) the maximum temperatures are 115°F and 124°F whereas on the Stand in the horizontal position (case 3) the maximum temperature has been reduced to 104°F.
2. Additionally, the aluminum conducts heat laterally reducing the difference between the maximum and average temperatures - from 12°F and 15°F in cases 1 and 2 to 5° in case 3.
3. The effectiveness of the Aluminum Desktop Stand as a heat sink also depends strongly on the configuration chosen by the user. Comparing cases 3, 4 and 5 the average temperature decreases with increasing inclination: 99°F at 0°; 88°F at 21°; 84°F at 37°.
4. The primary mechanism for cooling of the computer is free convection and the cooling rate increases with the angle between the horizontal and the plane of the computer keyboard. The Stand provides the angle for enhanced free convection and additionally leaves the area under the computer bottom unobstructed to maximize the area available for heat transfer.