1. CPU Cooling Benjamin Crummett

2. Objective Reduce CPU operating temperature. Reduce CPU operating temperature. Over clock the CPU without over heating it. Over clock the CPU without over heating it.

3. Starting Conditions Stock heat sink and fan. Stock heat sink and fan. CPU operating temperature 45°C. CPU operating temperature 45°C. Ambient air temperature in computer case 28°C. Ambient air temperature in computer case 28°C.

4. Increasing Air Flow 20 CFM50 CFM 20 CFM50 CFM

5. Analytical T ∞ = 28°C T ∞ = 28°C A fan =.0049m 2 A fan =.0049m 2 A fin =.0028m 2 A fin =.0028m 2 N = 66 N = 66 L =.04m L =.04m R eL = VL/ R eL = VL/ Nu = hL/k =.664 R eL 1/2 Pr 1/3 Nu = hL/k =.664 R eL 1/2 Pr 1/3 q = NhA fin (T s – T ∞ ) q = NhA fin (T s – T ∞ )

6. New Fan Results Original temperature 45°C. Measured CPU temperature 39°C. CPU temperature 39°C.Calculated CPU temperature 38.8°C. CPU temperature 38.8°C.

7. Over Clocking Results Increasing CPU speed from 2 GHz to 2.4 GHz increased CPU temperature from 39°C to 45°C. Increasing CPU speed from 2 GHz to 2.4 GHz increased CPU temperature from 39°C to 45°C. The new fan allowed the CPU speed to be increased 20% without increasing the temperature from it’s original state. The new fan allowed the CPU speed to be increased 20% without increasing the temperature from it’s original state.

8. Conclusions Increasing air flow velocity increases convective heat transfer rate. Increasing air flow velocity increases convective heat transfer rate.

9. Questions?