In the heat exchange calorimetry, heat evolved in the sample vessel placed in a water bath was exchanged freely with the ambient water. The thermal process was expressed by a simple differential equation. In practice, the temperature observed as an electric signal via a thermistor includes delay of response which was also expressed by a differential equation. Calorimeter systems of batch and titration types were constructed for estimation of total heat involving on-line and real time data processing of analog and digital computations. Appropriateness of the calorimetry proposed was examined by estimating total heat of reaction of THAM with 0.1mol dm-3 HCl for exothermic reaction and heat of solution of solid KCl to water for endothermic reaction. In both of batch and titration experiments, satisfactory results were obtained in comparison with those recommended by Montgomery et al. in 1977. In addition, instantaneous heat effect evolved electrically as a step function was followed with sufficiently speedy response.
