The Globe Thermometer in Studies of Heating and Ventilation

The effects of radiation and convection on the globe thermometer have been studied. Equations have been obtained, and alignment charts constructed, for the calculation of mean radiation intensity and of equivalent temperature from readings of the globe thermometer, air temperature and air velocity. The accuracy of these methods has been tested on observations made under industrial conditions. Taking direct thermopile observations as the standard, the mean radiation intensity values calculated from globe thermometer readings had an average error of 1·2 B.Th.U. per sq. ft. per hour. With eupatheoscope readings as standard, equivalent temperature estimates had a mean error of 1·2°. It is concluded that, while globe thermometer readings alone are unreliable as indications of the effects of the thermal environment, valuable results can be obtained by using the instrument along with an ordinary thermometer and a silvered kata-thermometer.