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View Full Version : liquid overfeed system ***** R404a







Krpac
18-04-2010, 08:59 PM
Hi
I am interested in the experience of liquid overfeed system with ***** R404a . I have one tunnel - Q=440 kW @ -35 C / +35 C . What is optimum circulation rate?

Dacosta
19-04-2010, 04:11 PM
http://www.refrigeration-engineer.com/forums/showthread.php?p=179389#post179389

"Remember R-507(404A) is expensive, going 4-1 means you need to have a larger pipe to reduce the friction losses though the pipe. Also you will have a larger refrigerant charge. Your evaporator efficiency will go up with 4-1 but so will your costs. consider economizing on the liquid feed to say 2-1 or 3-1. This may save you money in the long run."

Remember just increasing the recirculation rate just mean your evaporator can be smaller. By reducing the recirculation rate your evaporator needs more surface area to maintain the same amount of cooling. Going higher than 4:1 will see very little improvment in the evaporator. (once all the tubes are "wet"-ed no additional benefit will occur with more liquid).