The device consists of a test plate and a comparator plate, typically a black surface. When all physical parameters such as dimensions and temperature are kept identical for both plates, the heat losses from each are nearly the same except for radiation losses. The difference in power input between the plates is therefore attributed to their emissivity. Both plates are mounted within a panel enclosure with a Perspex front, and they receive input through separate dimmer stats, allowing their temperatures to be precisely controlled and maintained at the same level. This setup enables the emissivity of the test surface to be determined at various temperatures.

Experimental Objective 

measure the emissivity of the test surface in comparison to black surface

determine the emissivity of the gray surface using emissivity apparatus.

Specifications

·        Test and black aluminum plates, 160 mm diameter, mounted on a panel with internal mica heaters.

·        Voltmeter and ammeter with selector switch to measure power input to each heater.

·        Separate dimmer controls for individual plates.

·        Multichannel digital temperature indicator included.

Utilities required other than above supply

Space area of 1.5meters x 1meters at working height.

230V 15A, AC supply with earthing connection.