High pressure calorimetry; application to phase change under pressure

Calorimetry is a very versatile technique used to study phase change or reactions of any material. This paper presents a calorimeter which has been designed for studying phase change at elevated pressure. Its originality lies in that a pressure scan is realised at constant temperature. A differential calorimeter head was used as a pressurisation fluid. A high pressure pump driven by a step motor permits to obtain constant pressurisation or depressurisation rates. Data on the latent heat of pure water at -5°C, -10°C and -15°C are proposed. Some statements on the behaviour of the sample of water during the peak are presented and are discussed. Results were within 3% of the existing data from the literature.