[Mechanical Equipment Technology Edition] Daily Question 20191121: Basics of Refrigeration – Refrigeration Pressure-Humidity Diagrams – Refrigeration Cycles (5)

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This post was last edited by Zhang Xinlin from Binglun Environment on 2019-11-25 at 12:56. [Daily Question] is divided into three sections: fundamentals of refrigeration, equipment selection options, and maintenance of refrigeration equipment. [Reward Rules] Those who comment on this post will receive 1–3 wealth points; those who provide accurate answers will get 10–15 points. The rewards are valid for two days, and the answers will be announced after that period. Fundamentals of Refrigeration section – Pressure-enthalpy diagram – Refrigeration cycle (5). I. Overview: Previously, we analyzed the changes in enthalpy during the four processes of a refrigeration cycle: compression, condensation, throttling, and evaporation. The diagram below shows the pressure-enthalpy diagram, with enthalpy on the horizontal axis and pressure on the vertical axis. As an example, in process 4–1, the pressure remains constant while the enthalpy increases; this rules out the possibility of it being a compression process, as pressure increases during compression. Evaporation absorbs heat, causing the enthalpy value to increase; moreover, evaporation is a process of latent heat, that is, a change in state while the pressure remains constant. So the 4–1 process is an evaporation process. Question: The process from 2 to 3 is ( ). The process from 1 to 2 is ( ). The process from 3 to 4 is ( ). ============================== Premium promotion: Daily questions on mechanical equipment -- refrigeration sector, covering their value and functions. https://bbs.hcbbs.com/thread-2848974-1-1.html Internal training materials for manufacturers of screw refrigeration compressors related to mechanical equipment. https://bbs.hcbbs.com/thread-2850090-1-1.html