Dear all,
We designed a NH3 thermosiphon oil cooler, shell and tube heat exchanger, ammonia boiling in tubeside, duty:300KW, tube counts:717, circulation ratio:3:1, oil inlet/outlet temperature:80/40 Deg C, ammonia: 38/39 Deg C.
But after running some days, we found that it didn't work well, the ammonia liquid has 2 Deg C sub-cooling, we measured some parameters as follows: duty:251KW, oil:87.7/49, ammonia:33.3/35.4, and if the entironment temperature becomes higher ,the oil cooler performance will become much worse.
We think the area we designed is less than the aera required.
could anyone help me to figure out this problem?? and give some advice on thermosiphon oil cooler designing?

thank you very much!


cygbob