Experiments of thermodynamics with a Peltier cell
Peltier cells, also called frigistors, consist of a series of junctions made of different metals which can either work as thermocouples (i.e. when the even junctions are thermally coupled to a cold reservoir and the odd junctions are anchored to a hot reservoir, the cell produces a voltage drop across the terminals), or as a heat pump (i.e. when a current flows through the junctions heat is transferrd from the face thermally anchored to the even junction to the face anchored to the odd junctions, or viceversa, depending on the direction of the current flow).
An educational kit,
study the behavior of a Peltier cell can also be used
several interesting thermodynamics processes:
liquid-vapor phase transitions, supercooling, freezing
and boiling point elevation (using simple binary
salt/water, alcohol/water), latent heat of fusion
of supercooling of water: at the time t=318 s there
is a discontinuity
in the the water temperature (black line)
phase transition which starts at T = -4.3
Celsius. Also the cup
temperature heats-up suddenly (grey line).
Peltier kit includes:
Peltier kit requires (not included):