This photo shows the most recent and accurate dual-type calorimeter. The cell is surrounded by a jacket through which water flows at a constant, known rate. This assembly is placed within a vacuum dewar, thereby allowing any heat leaving through the lid to be captured by the flowing water. Stirring is used to reduce any temperature gradients within the cell. The open-circuit voltage can be measured either at a small spot using a Luggin capillary or an average value for the entire cathode can be obtained.
Temperature is measured at two levels within the electrolyte and at the cathode.
A recombiner is located within the cell so that no gas leaves the system except the orphaned oxygen. Shown is a more detailed view of the new calorimeter. Normally the vacuum dewar is raised and covered by an insulated lid. A box containing the thermistor reference resistors is on the left. Resistors for measuring current through the cell are on the right.