Thermal Radiation Calorimeter for Measuring the Specific Heat Capacity of Liquid Samples

A new thermal radiation calorimeter for measuring the specific heat capacity of liquid samples continuously in the temperature range from 280 to 360 K is described. The heat input to the sample cell from the heater by thermal radiation is estimated using the effective emissivity, which is the apparatus constant. The heat capacity of a sample can be calculated from the temperatures of the sample and the heater, and the temperature change rate of the sample. The present sample cell was made of Pyrex glass; therefore most liquid samples do not react with the sample cell, and blackening of the surface of the sample cell is not necessary in the present temperature range. The specific heat capacities for ethanol, ethylene glycol, n-heptane, n-valeric acid, and water+ethanol mixtures were measured to confirm the reliability of the present calorimeter.