[Mechanical Equipment Technology Edition] Daily Question 20170808: Refrigeration Principles (4)
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This post was last edited by YORK Industrial Refrigeration on 2017-8-8 at 12:57. Starting from now, in order to enhance communication among members, a 【Daily Question】 campaign has been launched on the Mechanical Equipment Technology forum; we hope everyone will participate actively to progress and improve together! ! ! Rewards: 3 wealth for active participation, 10 wealth for correct answers. This question is valid for two days; no scoring will be given after that. Title: The figure below shows the pressure-enthalpy diagram most widely used in refrigeration. Please analyze the thermodynamic process of throttling based on this diagram: http://p1.so.qhimgs1.com/t01e5e56369de0b6c61.jpg Answer: Content hidden in this post Content hidden in this post Content hidden in this post Content hidden in this post Content hidden in this post Isentropic pressure reduction ================================ Promotion: Petrochemical sector – “Creative Ideas for Energy Savings” campaign (the second phase is currently in progress): http://bbs.hcbbs.com/thread-1666758-1-1.html (Source: Haichuan Chemical Industry Forum) 2017 Coal Chemical Industry – “My Technical Upgrades”: http://bbs.hcbbs.com/thread-1786290-1-1.html (Source: Haichuan Chemical Industry Forum)
In the system, the compressor is responsible for compressing and transporting the refrigerant vapor, which results in low pressure in the evaporator and high pressure in the condenser. It is the heart of the entire system ； The expansion valve (throttle valve) thins and reduces the pressure of the high-pressure liquid refrigerant, while also regulating the flow rate of it into the evaporator ； The function of the evaporator is to produce cold air; the refrigerant absorbs heat from the medium to be cooled within the evaporator, thereby achieving the purpose of generating cold air ； The condenser is responsible for outputting
During the throttling process, the pressure of the refrigerant drops from the condensing pressure to the evaporating pressure, and its temperature drops from the condensing temperature to the evaporating temperature, entering the two-phase region.
1-2 Adiabatic compression process 2-3 Isobaric heat release process 3-4 Constant h 4—1: The refrigerant absorbs heat at constant pressure in the evaporator
1-2 Adiabatic compression process 2-3 Isobaric heat release process 3-4 Constant h 4—1: The refrigerant absorbs heat at constant pressure in the evaporator
The high-pressure liquid is depressurized in the expansion valve, turning into a superheated liquid medium that then enters the evaporator, thus restarting the initial cycle.