Power Balance Equation of Membrane Transport System: A Basis for Network Thermodynamics.

Network thermodynamicsprovides a tool of analysis and synthesis of an open dynamic system.On an open dynamic system, processes of energy and entropy, that is, their transports and their changing rates are considered.The first law of thermodynamics can be expressed by a balance between the energy storage and the net energy transport.The second law of thermodynamics can be expressed by a balance between the entropy storage and sum of the entropy production and the net entropy transport.Both balance relations of energy and entropy can be unified when we define an availability function.Using the availability function and assuming local equilibrium, the thermodynamic basis for network thermodynamics is discussed.