Molecular fan cooling monitor

A.Background

Heat transfer usually occurs by three modes: Conduction, Convection and Radiation. Under the same conditions for conduction and convection, radiation from a hot body can help dissipate heat effectively and hence enhance the cooling effect.

The radiation property of a material is characterized by the surface emissivity (ε) which is dependent on the surface condition. Emissivity of a surface is defined as the ratio of energy radiated by the surface to the energy radiated by a black body at the same temperature. A perfect black body emits all radiation absorbed by it and has εvalue of 1. Regular surfaces have εvalues between 0 and 1.

The radiant power emitted per unit surface area is calculated by Stefan’s Boltzmann law:

, where

ε: emissivity of radiant surface,

T: surface temperature (K),

A: surface area (m2),

κ: Stefan-Boltzmann constant (5.67 x 10-8 W/(m2K4))

The Raditive cooling Monitor can estimate the emissivity and radiative power (heat dissipated by radiation) of a surface.

Operating Procedure

1. Load a sample on the heater disk.

2. Slowly rotate the up-down wheel until upper sponge is slightly squeezed.

3. Connect the heater plug to heater tower. Check heater and temperature sensor are in place.

4. Check power cable and USB interface between computer and Cooling Monitor controller. Set front power dial at lowest position (zero).

5. Pull triger button of IR thermometer. Press lock button to keep it on. If no ‘lock’ is displayed on LCD, then thermometer will turn off after a minute.

6. Power on switch on back panel of Cooling Monitor Controller. The green light will be on after self reset.

7. Start computer.

8. Start CoolMon program. Check for any error messages. If error message is shown, check interface and power cable.

9. After self test, the channel values are displayed on the screen.

10. Increase power dial slowly to 30%, watch the Volt and Ampere changes on the CoolMon screen. Temperature will begin to rise within few minutes and shown on the RTD reader, IR meter and CoolMon screen. You may begin to record temperature by Start button. A steady-state of temperature will take about 30 min. The number at lower part of RTD reader indicates maximum temperature that is allowed for system (150 °C).