关键词: 热力学第一定律, 热交换器, 能效评价, 传热系数, 传热效能, 努塞尔数, 功率因子, 质量因子

Abstract:

With the implementation of national policy on green and low-carbon development, the energy efficiency evaluation of heat exchangers is becoming more and more important. Based on the first law of thermodynamics, the typical methods and evaluation indicators for energy efficiency evaluation of heat exchangers are sorted out, and the characteristics of each evaluation method and indicator are analyzed. The evaluation methods mainly focus on factors such as heat transfer coefficient, pressure drop, heat load, and heat transfer area. For refrigeration, heating and liquid-liquid phaseless transformation heat exchange scenarios, fluid physical properties and heat exchanger types are relatively single, so the evaluation methods of energy efficiency indicator and energy efficiency have proposed clear energy efficiency grades. For the refining and chemical industry, it is difficult to use a single method for energy efficiency evaluation because of the complex physical properties of fluid and the diverse types of heat exchangers. In practical applications, it is suggested to conduct a comprehensive compare of heat transfer performance, pressure drop and heat exchange capacity per area based on the specific situation and similar structure type, and obtain energy efficiency evaluation results that have guiding significance for production and operation.

Key words: the first law of thermodynamics, heat exchanger, energy efficiency evaluation, heat transfer coefficient, heat transfer efficiency, Nu, power factor, quality factor