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【Daily Question】Divided into three sections: Basics of Refrigeration, Equipment Selection Solutions, and Maintenance of Refrigeration Equipment. 【Reward Rules】All users 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 correct answers will be announced after that period. Basics of Refrigeration section – Pressure-enthalpy diagrams – Refrigeration calculations (5). I. Overview In refrigeration calculations, pressure-enthalpy diagrams are used; for example, when selecting a throttle valve, it is necessary to know the flow rate of the refrigerant, and when choosing an evaporative cooler, it is necessary to know the heat rejection capacity, among other things. Here are several basic terms used in pressure-enthalpy diagram calculations: 1. Cooling capacity per unit mass, KJ/KG; 2. Cooling capacity per unit volume, KJ/m3; 3. Mass flow rate of the refrigerant, KG/h; 4. Volume flow rate of the refrigerant, m3/h; 5. Condensation heat load per unit mass, KJ/KG; 6. Theoretical compression work per unit mass, KJ/KG; 7. Coefficient of Performance, COP. These 7 parameters will be discussed in the daily questions to follow when it comes to cooling calculations. Question 1: The cooling process can be simply understood as a process of heat absorption and heat release. The area where heat is absorbed is the cooling section, located in the evaporator, where the refrigerant evaporates and absorbs heat. The area where heat is released is the condenser, where the gaseous refrigerant turns into a liquid state, releasing heat in the process. The compressor does work on the refrigerant, increasing its pressure and temperature and thus raising its internal energy; this process can also be considered as heat absorption. According to the law of conservation of energy, heat absorbed equals heat released. So what is the relationship between the heat released during condensation, the compression work, and the cooling capacity? https://attach01.hcbbs.com/forum/201912/21/003130zr7178e81nj764yd.png ============================== High-quality promotion: Daily questions on mechanical equipment – refrigeration sector; 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