Digital computer simulation of complex radiant heat load.
Abstract The exchange of radiant heat between an absorber and a variety of radiators in its surroundings is capable of calculation by digital computer. When the absorber is characterized as a black body, the calculated results may represent the maximum potential radiant heat load upon a man occupying the absorber location. Calculations of heat exchange for a matrix of absorber locations within a work space permits the construction of isopleths of heat load in that work space; this may be done for any elevation of interest. The contribution made by each individual radiator to the heat load on absorbers at the various locations may be obtained. Repeated computer runs using simple changes in input data may be used to simulate various alternatives for control of radiant heat exposures. Use of a digital computer permits mathematical assessment of radiant heat exchange problems for which manual calculations would be prohibitively time consuming and costly.
Calculation of Complex Radiant Heat Load From Surrounding Radiator Surface Temperatures
Abstract A method for calculating the radiant heat exchange between an absorber and individual radiating components in its surroundings is reported. Radiator surface temperatures, ambient and absorber temperatures, and configuration factors for radiating components in the surroundings are used in the customary radiant heat exchange formulae. Simplified methods for calculating or estimating configuration factors for radiators of various shapes solely from angles, subtended at the absorber by the radiators are presented. The method has been verified in the laboratory under controlled conditions and has been used to advantage in the field studies. The method has advantages over the globe therometer method in certain applications.
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.