Specific heat measurement

The specific heat of a sample is the energy that must be supplied to this sample in the form of heat to vary its temperature. It is also called heat capacity or thermal capacity.

Specific heat values ​​are usually expressed in J/g/°C, but other units are sometimes used: J/mol/K, etc.

Measurement method

At Calnesis, the specific heat of your samples is measured by calorimetry, by precisely measuring the heat flux exchanged by the sample with the outside during a precise controlled evolution of the temperature.

Temperature range

Commonly, Calnesis performs specific heat measurements between -80 and over 600°C. For this purpose, Calnesis has several calorimeters, each with different characteristics: DSC, microcalorimeter, Calvet calorimeter, etc. For measurements beyond this temperature range, solutions exist. It is possible in particular to use devices of the thermobalance type equipped with a heat flow sensor. Do not hesitate to consult us if necessary!

Sample size and type

Calnesis adapts the choice of instrument and its cells used to your desired temperature range, but also to the shape of your samples: powders, pastes, liquids, solids, etc.

The calorimeter used for specific heat measurement depends on the desired temperature range, but also on the characteristics of your samples: shape, physical state, heterogeneity, etc.

Jean-Claude Neyt, COO and Lab Manager, Calnesis

Thermal stability

The samples analyzed must be thermally stable over the entire temperature range explored. No change of state, evaporation of solvents, thermal degradation, must take place during the temperature ramps carried out. Indeed, the heat flux corresponding to these additional effects would be added to the measured heat flux which is used to calculate the specific heat.

Accuracy

Most often, Calnesis performs specific heat measurements with an accuracy better than 3%. This precision varies according to the type of calorimeter used, the temperature, but also and above all your samples (heterogeneity of the latter, their physical state, etc.).

Bibliography

Experimental Data and Modeling of Solution Density and Heat Capacity in the Na–K–Ca–Mg–Cl–H2O System up to 353.15 K and 5 mol·kg–1 Ionic Strength
J. Chem. Eng. Data
DOI: 10.1021/acs.jced.7b00553