[Mechanical Equipment Technology Edition] Daily Question 20180706: Refrigeration Systems — Refrigeration Parameters (16)
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This post was last edited by YORK Industrial Refrigeration on 2018-7-9 at 09:35. This year’s 【Daily Question】is divided into three categories: screw refrigeration compressors, refrigeration systems, and oil circuit systems, aiming to provide a comprehensive understanding of refrigeration technology. (If you encounter something you don’t know or can’t answer, please actively look up information; as you do so, your skills will improve!) ) All participants in the comments on this post will receive 1-3 wealth points; those who give complete answers will receive 10-15 points, with the validity period being two days. ============================== Refrigeration system – Refrigeration parameters (16): What are the formulas for the small temperature difference/approaching temperature at the condenser and the evaporator? Evaporation approach temperature = Outlet temperature of chilled water – Evaporation temperature of refrigerant. Condensation approach temperature = Condensation temperature of refrigerant – Outlet temperature of chilled water. ============================== Premium promotions: Mechanical equipment——Videos on the repair and adjustment of York compressors: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1806833. Mechanical equipment——Maintenance procedures for York screw compressors: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1806833. Mechanical equipment——Upgrading of York Quinton control centers: https://bbs.hcbbs.com/thread-1804837-1-1.html. Mechanical equipment——Major repairs of GEA Grasox screw compressors: https://bbs.hcbbs.com/thread-1800467-1-1.html. Mechanical equipment——Disassembly and maintenance of British HOWDEN screw compressors: https://bbs.hcbbs.com/thread-1832529-1-1.html. Mechanical equipment——Disassembly and maintenance of Japanese Maekawa MYCOM screw compressors: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=
Evaporation approach temperature = Outlet temperature of chilled water – Evaporation temperature of refrigerant. Condensation approach temperature = Condensation temperature of refrigerant – Outlet temperature of chilled water
The small temperature difference in the evaporator refers to the difference between the saturated temperature of the refrigerant in the evaporator and the outlet temperature of the chilled water; the evaporation approach temperature = chilled water outlet temperature – refrigerant evaporation temperature； The small temperature difference in the condenser refers to the difference between the saturated temperature of the refrigerant in the condenser and the temperature of the cooling water at the outlet; the condensation approach temperature = refrigerant condensation temperature – cooling water outlet temperature ；
Evaporation approach temperature = chilled water outlet temperature - refrigerant evaporation temperature. Condensation approach temperature = Refrigerant condensation temperature - Cooling water outlet temperature.
The difference between the “saturation condensation temperature of the refrigerant” in the condenser and the “temperature of the cooled water exiting the system” is referred to as the “small temperature difference,” which is usually 1-2°C. Similarly, in an evaporator, the difference between the \"saturated evaporation temperature of the refrigerant\" and the \"temperature of the chilled water outlet\" is also referred to as the small temperature difference. For full-liquid evaporators, this value is around 1°C or a little over 1°C; for dry evaporators, it is higher, at around 5°C or more.
Evaporation approach temperature = Outlet temperature of chilled water – Evaporation temperature of refrigerant. Condensation approach temperature = Condensation temperature of refrigerant – Outlet temperature of chilled water
What is the significance of these two temperature differences? What practical value do they hold? :)
If you read more of the posts I’ve shared, you’ll understand