flow rate

[Rajkumar]

How we can increase the ammonia flow rate without using overfeed pump

[keepitcool]

What are you feeding? What is the current method? High pressure feed, Pumper drum?

[Rajkumar]

now the feeding through surge drum. I want to increase the flow rate by 1.5 :1

[keepitcool]

How high is the surge drum above the coil? Is the coil not performing properly or have your needs changed?

[Rajkumar]

surge drum bottom is 500 mm above the wet return connection on coil.

[US Iceman]

now the feeding through surge drum. I want to increase the flow rate by 1.5 :1

If the evaporator is gravity flooded via a surge drum, why do you need to increase the ammonia flow rate by 50%???

[Magoo]

Are you feeding sub-cooled liquid into surge drum, and what is the dry suction outlet relationship ? you are asking for trouble by changing levels in surge drum. Hopefully you have a spare compressor in stock, because you are bound to break something sooner than later. You change system balance and the system will bite you. Generally in the wallet. Iceman chime in around-a-bout now, with your wise and extended experience.
magoo

[US Iceman]

Iceman chime in around-a-bout now, with your wise and extended experience.

Thanks for the vote of confidence!!

I was hoping to draw out some more comments before I jumped into the fray. There seems to be a misunderstanding of how these systems work.

If this is indeed a gravity flooded evaporator with a surge drum the flow rate is already greater than 1.5:1. At full load the circulating rate is probably around 8 or 10! The higher load creates a lot more gas, so the circulation rate actually increase as the load on the coil increases. It decreases as the load is reduced.