【Mechanical Equipment Technology Edition】Daily Question 20180707: Refrigeration Systems — Refrigeration Parameters (17)
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This post was last edited by YORK Industrial Refrigeration on 2018-7-13 at 08:56. 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!) ) Those who comment 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 (17): The small temperature difference of the condenser = Condensation temperature – Outlet temperature of the cooling water. Explain the meaning of this formula (state your own understanding of it). Water is used to cool the refrigerant into a liquid state; as a result, the water temperature rises while the refrigerant’s temperature drops to its saturated level. The closer the temperature of the cooled water is to the saturated temperature, the better the heat exchange efficiency. For example, when a hot object comes into contact with a cold object, eventually both objects end up at the same temperature ； If there is copper tube heat exchange between two objects, their temperatures can never be identical; it can only be said that the better the heat exchange effect, the more similar their temperatures become after cooling. ============================== High-quality 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=
There are no fixed values for the condensation temperature and the outlet temperature of the cooling water; when the refrigeration unit does not emit any alarms, the temperature difference between the inlet and outlet water is generally below 5 degrees. As long as the high and low pressures of the machine are within normal ranges, there is no problem. The condensation temperature is the critical temperature at which a substance changes from a gaseous state to a liquid state. Different substances have different condensation temperatures. For the same substance, changes in external pressure also lead to changes in the condensation temperature. Generally, as external air pressure increases, the condensation temperature rises; conversely, it falls.
The condensation temperature is the critical temperature at which a substance changes from a gaseous state to a liquid state. Different substances have different condensation temperatures. For the same substance, changes in external pressure also lead to changes in the condensation temperature. Generally, as external air pressure increases, the condensation temperature rises; conversely, it falls.
The difference between the “saturation condensation temperature of the refrigerant” in the condenser and the “temperature of the cooled water at the outlet” is referred to as the “small temperature difference,” which is usually 1-2°C.
The small temperature difference in the condenser = condensation temperature – outlet temperature of the cooling water. In the condenser, the cooling water heats up as it exchanges heat with the refrigerant; at the same time, the refrigerant is cooled. The so-called condensation temperature is the saturated temperature of the refrigerant. Since the outlet temperature of the cooling water is lower than this condensation temperature, it is possible to cool the refrigerant. Due to the flow of water in the tube side and the refrigerant in the shell side, separated by the copper tubes, the two fluids do not reach exactly the same temperature; that is, the temperature difference is not zero, but it is very small. The smaller the temperature difference, the better the condensation effect.
The small temperature difference in the condenser = Condensation temperature – Cooling water outlet temperature. In the condenser, the cooling water heats up as it exchanges heat with the refrigerant; at the same time, the refrigerant is cooled. The so-called condensation temperature is the saturation temperature of the refrigerant. Since the cooling water outlet temperature is lower than the condensation temperature, this allows the refrigerant to be condensed. Due to the flow of water in the tube side and the refrigerant in the shell side, separated by the copper tubes, the two fluids do not reach exactly the same temperature; that is, the temperature difference is not zero, but it is very small. The smaller the temperature difference, the better the condensation effect.