Modelling of cryocooler in COMSOL

Hi,

I would like to model a heat extractor/cold stage in cryocooler in COMSOL. The cold stage of the cryocooler extracts heat from the attached mass through conduction. The cold stage maintains cooling capacity vs temperature plot e.g. 40W at 45 K, 20W at 35 K etc. I would like to know the temperature distribution along the mass which are attached to the cold stage so that we can estimate the heat load of the attchment.
Kindly suggest how to model the cold stage with cooling capacity. Kindly suggest whether heat source with negative heat load will solve the purpose? In that case how will I incorporate various cooling capacity vs temperature data onto it.


Thanks and regards
Ananya Kundu