Background: In Icepak there is only a 2D heat exchanger object available. On the other hand the thermal specification for the 3D Resistance object is limited to constant or spatial distributed (predefined) power. Solution: A combination of 3D Resitance and 2D Heat Exchanger objects is possible. The 3D Resistance (no thermal specification) gives maximum control of the pressure losses in different directions. A number of Heat Exchanger objects (no pressure loss specification), placed in the 3D Resistance zone, allows heat exchange controlled by the temperature difference between local Fluid and external (cooling/heating) Fluid. Obviously, the number of Heat Exchanger objects in the Resistance zone will define the temperature and heat exchange resolution.