Abstract:
A Microsoft FORTRAN 77 algorithm for calculation of the thermal absorptance and emittance of
materials for solar photothermal applications is presented. It replaces the Mathematica software
package used for an earlier paper and uses data from sample heating and cooling histories obtained in
an absorption calorimeter. The calorimeter is automated with a Z80 microprocessor system, which has
an operating system (OS) and control programs resident in a block of type 2716 EPROMs with a working
memory comprising Hitachi type 6116 static RAMs. The system acquires data from the sample
through thermocouples, filters, amplifiers and analogue-to-digital signal converters (ADCs) for temporary
storage in the on-board RAM. The raw data are uploaded to an IBM PS/2 microcomputer for display and
processing. Solutions of heat balance equations of the calorimeter are computed from the transient
temperature history data using analytical and numerical methods. Results obtained for commercial
copper and aluminium samples using a 60 W tungsten - halogen lamp are discussed. They compare well
with those from the Mathematica package
