the class of components which produce work output.
the power output of the work producing component
(Forall (?Self ?Time)
(<=> (Active ?Time Work-Producing-Component ?Self)
(And (Work-Producing-Component ?Self)
(Active ?Time Thermal-Component ?Self))))
(=> (Work-Producing-Component ?Self)
(Quantity.Dimension (Power-Output ?Self) Power-Dimension))