Lost work maximum power

Exergy losses are Erl0SS( = 7i l,S pri id,. Table 4.12d shows the distribution of lost work in various units of the power plant. The maximum lost work occurs in the boiler/fumace unit, while the minimum lost work occurs in the pump. 

That is to say, if the heat energy Qi enters into a process involving a decrease of temperature, and the maximum work is not developed and stored in available form, there has been decrease of the power of the amount of energy originally represented by Q to do work, which is another way of stating that the entropy has increased. If, however, all of the processes are reversible no such power of doing work is lost and the entropy remains constant. Equations (10) and (11) contain the essentials of the Second Lazo of Thermodynamics,... 

The concept of overpotential is a powerful means for quantifying the performance of an electrochemical system. It applies at multiple levels the overall cell, the individual electrodes, and the processes occurring at those electrodes. All components of overpotential can be measured, so the method is of value in any electrochemical application. In most cases, component overpotentials may be considered independently. This simplification greatly aids the development of an electrochemical system as it enables isolated study of a part of the overall process. Since overpotentials are a deviation from ideality, which is the condition of maximum work, they quantitatively express the work lost in a system that results from a particular electrode process. In so doing, they express the inefficiency of electrochemical systems. 

The necessary condition of the maximum (work) is, that in the bodies employed to realize the motive power of heat there should not occur any change of temperature which may not be due to a change of volume. Reciprocally, every time that this condition is fulfilled the maximum will be attained. This principle should never be lost sight of in the construction of a heat engine it is its fundamental basis. If it cannot be strictly observed, it should at least be departed from as little as possible. ... 

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