What do the thermoelectric parameters Imax, Vmax, dTmax and Qmax mean?
As current flows through a material, heat is generated. Thermoelectric material is no different. There is a point where the heat generated internally offsets the TECs ability to pump heat. Each TEC has a limit on how much heat that it can pump. This limit is referred to as Qmax. The current associated with Qmax is referred to as Imax. The corresponding voltage across the coolers is referred to as Vmax. If a TEC is completely insulated and isolated from the environment and running at Imax, it will produce its maximum temperature difference, dTmax. At this point it will also be pumping no heat whatsoever. As heat is applied to the cold side of the TEC, the temperature differential is suppressed. Effectively, one trades temperature differential for heat pumping. As such, if the temperature differential is 0, the corresponding heat load is Qmax. The coefficient of performance (COP) is defined as the amount of heat pumping one gets for each unit of electrical power supplied.
