Microsoft Word - Cengel and Boles TOC _2-03-05_.doc

Unlike energy, the value of exergy depends on the state of the environment as well as the state of the system. Therefore, exergy ...

when the direction of work is taken to be from the system (otherwise it would be P dV). The pressure Pin the P dVexpression is ...

or, on a unit mass basis, (8–18) For stationaryclosed systems, the kinetic and potential energy terms drop out. When the propert ...

The final expression is called flow(or stream) exergy,and is denoted by c (Fig. 8–23). Flow exergy: (8–22) Then the exergy chang ...

Chapter 8 | 439 P 1 = 0.14 MPa T 1 = –10°C T 2 = 50°C P 2 = 0.8 MPa T 0 = 20°C COMPRESSOR FIGURE 8–25 Schematic for Example 8–8. ...

8–5 ■ EXERGY TRANSFER BY HEAT, WORK, AND MASS Exergy, like energy, can be transferred to or from a system in three forms: heat, ...

Heat is a form of disorganized energy, and thus only a portion of it can be converted to work, which is a form of organized ener ...

Note that heat transfer through a finite temperature difference is irreversible, and some entropy is generated as a result. The ...

Exergy flow associated with a fluid stream when the fluid properties are variable can be determined by integration from (8–28) w ...

This equation can be expressed as the exergy of an isolated system during a process always decreases or, in the limiting case of ...

or (8–35) This relation is referred to as the exergy balanceand can be stated as the exergy change of a system during a process ...

where Qkis the heat transfer through the boundary at temperature Tkat loca- tion k.Dividing the previous equation by the time in ...

Chapter 8 | 447 Analysis We consider a general closed system (a fixed mass) that is free to exchange heat and work with its surr ...

448 | Thermodynamics this process since the state and thus the exergy of the wall do not change anywhere in the wall. 3 Heat tra ...

Chapter 8 | 449 determine (a) the exergy of the steam at the initial and the final states, (b) the exergy change of the steam, ( ...

450 | Thermodynamics That is, if the process between states 1 and 2 were executed in a reversible manner, the system would deliv ...

Chapter 8 | 451 (d) Noting that the decrease in the exergy of the steam is the exergy sup- plied and the useful work output is t ...

452 | Thermodynamics (b) The reversible work, which represents the minimum work input Wrev,inin this case, can be determined fro ...

Chapter 8 | 453 Thus, Integrating, we get The first term on the right-hand side of the final expression above is rec- ognized as ...

454 | Thermodynamics (a) Noting that no energy enters or leaves the system during the process, the application of the energy bal ...