Lumped Model with Cycle-Averaged Heating

The simplest lumped model for estimating PSII target temperatures is one which assumes that the targets and base are all at a single temperature. This allows use of the following equation:

where is the total mass of the base and targets, is the mass-averaged heat capacity, is the total heated area, is the cycle-averaged heat flux applied to that area, is the total radiating area, is the radiation heat flux lost from that area, and is the total heat lost due to conduction. Note that the emissivity used in the calculation of the radiative heat flux must be a surface-averaged value, since the targets and base may have different emissivities.