Construction, calibration and testing of a decimeter-size heat-flow calorimeter

A heat-flow calorimeter was designed and built. Its measurements are 26 cm × 26 cm × 26 cm (17.6 dm3). 18,796 thermocouples are used to measure the heat-flow from the vessel walls to the outer walls, for which temperature is controlled within 0.01 °C from 0 to 100 °C by a refrigerating/heating circulator. Homogeneity of temperature in the measuring vessel is improved by a fan with constant power. The calibration was performed with an electric heater, with input power up to 50 W. The device constant is 5.8954 ± 0.0025 W V−1; the time constant is 501.7 ± 3.2 s; the uncertainty is 0.6% at 2 W to 0.06% at 50 W. Nonlinearity of this calorimeter is analyzed. The calorimeter can be utilized for studies of kinetics and thermodynamics of physical, chemical and biological systems of decimeter-size. A Sony 26650 Li-ion rechargeable battery was tested with this device during charging and discharging, and an electrolytic cell with Pd-D2O was also tested with this device.