5. Adiabatic calorimeters

5.1 Measuring principle

Adiabatic methods, by definition, avoid any heat exchange between the sample and the environment. Therefore, all the energy released by the reaction whose thermal characteristics we want to determine is transformed into accumulation, i.e. temperature rise (we assume the reaction is exothermic). To achieve this condition, the exchange term in the heat balance must be zero. The equipment must therefore either provide perfect thermal insulation, or limit heat loss by means of a suitable compensation device. Here are two examples of such techniques:

• the Dewar vase as a representative of passive adiabatic calorimeters (thermal insulation), since the vase is double-walled in silver to prevent radiation losses, and the...