能量贬值论——热力学定律教学改革的思考(Ⅱ)

On the energy devaluing -Thoughts about the instructional reform of thermodynamics law (Ⅱ)

能量不仅在数量上具有守恒性,在质量上具有品位性,而且在转换与传递过程中具有贬值性.指出过程的不可逆性必然导致能量品位的降级,过程的推动力愈大,不可逆性程度愈大,导致能量的贬值就越大;通过典型过程能量贬值的分析,阐明了加大推动力来加快过程速率的传统观念是欠科学的;引进有效能损失与有效能效率,建立统一损失尺度与完善性尺度,有利于评价各种热工设备与生产过程的优劣;大力开展有效能衡算法,有利于研究能量的无形损失,全面地反映出用能过程中存在的问题;提出了减轻能量贬值的技术措施,科学地指出了节能的重点与方向.

Energy is not only characterized by conservation in quantity and grade in the quality but alsoby devaluing nature in conservation and its transmission process.This paper dealt with the foundation of energy grade theory and made further inquiry into the devaluing nature of energy.It pointed out that the procedural irreversibility leads inevitably to the reduction of system energy grade.With the growth of the driving force of process,the irreversibility level of process increases,hence a greater energy devaluing.Through the analysis of the typical process energy devaluing,this paper expounded that it is unscientific of the traditional concept to quicken the process speed by increasing the driving force;that it is significant for assessing various heat facilities and production process to introduce exergy loss and exergy efficiency as well as to build unified loss scale and unified perfect nature scale;and that vigorous development of the exergy balance is helpful in studying invisible exergy loss and adequately reflecting the problems existing in the process of energy utilization.The paper also put forward the technological measures of reducing energy devaluing and advisably proposed the energysaving keys and orientation.