(火积)损失是热力学过程中系统(火积)的减少量,它等于流入系统的(火积)流与流出系统的(火积)流之差,也等于(火积)耗散和功(火积)之和。对于传热过程,(火积)损失即为(火积)耗散,为(火积)损失的不可逆部分,反映了热力学第二定律。对于卡诺循环,(火积)损失即为功(火积),具有可逆特性,体现了热力学第一定律。对于包括传热过程和热功转换过程的系统,(火积)损失即包括(火积)耗散也包含功(火积)。(火积)损失的各个组成部分可以通过以热流和温度为横、纵坐标的T-q图上的面积描述。(火积)损失可应用于包含热功转换的过程以优化系统输出功,算例表明在一定条件下最大输出功率和最大(火积)损失率相对应。
Entransy loss is the entransy reduction of the system in the thermodynamic process, which is the difference between the total entransy flow into and out of the system. It includes entransy dissipation and work entransy. For heat transfer processes, it is entransy dissipation, which is the irreversible section, and demonstrates the second law of thermodynamics. For the Carnot cycle, entransy loss is work entransy, which is reversible and reflects the first law of thermodynamics. For the system that includes both heat transfer processes and heat-work conversion process, entransy loss is the sum of entransy dissipation and work entransy. The constitution of entransy loss can be expressed by T - q diagram that uses heat flux as the horizontal axis and temperature as the vertical one. Entransy loss can be used for optimizing output work, and the numerical example indicates that the maximum entransy loss rate corresponds to the maximum output power under certain preconditions.