new to forum, head pressure questions.

[dewax-chiller]

like the title says, new to forum. i have approx 3 years here so i'm still quite green.
i work in an oil refinery that has been converted to wax production.
that being said our nh3 system has approx 3000gal capacity of nh3.
we use fes screw compressors and 2 different types of condensers. fes evaporative condenser, and twin open tower condensers. well water is used in both. we do not use a pressurized nh3 feed loop (i know it has a name but i do not know much about them due to not having one). we use double pipe chillers 8" outside pipe 6" inside (nh3 on outside) with 5 accumulators fed from a central header and 2 different tube and sheet style chillers further down the line..

the first of millions of questions i have is this:
as far as head pressure on either type of condenser, what is too much and when is too little not enough? there is an ongoing speculation here that the higher the better because it is "pushing the nh3 to our furthest chillers better", others (like myself) believe that lower is better to let the compressors not have to work against the excess in pressure at the condenser.

[gregd1401]

What type of expansion device do you use? Some require a considerable head pressure to feed while others do not need anywhere near as much.

[Segei]

like the title says, new to forum. i have approx 3 years here so i'm still quite green.
i work in an oil refinery that has been converted to wax production.
that being said our nh3 system has approx 3000gal capacity of nh3.
we use fes screw compressors and 2 different types of condensers. fes evaporative condenser, and twin open tower condensers. well water is used in both. we do not use a pressurized nh3 feed loop (i know it has a name but i do not know much about them due to not having one). we use double pipe chillers 8" outside pipe 6" inside (nh3 on outside) with 5 accumulators fed from a central header and 2 different tube and sheet style chillers further down the line..

the first of millions of questions i have is this:
as far as head pressure on either type of condenser, what is too much and when is too little not enough? there is an ongoing speculation here that the higher the better because it is "pushing the nh3 to our furthest chillers better", others (like myself) believe that lower is better to let the compressors not have to work against the excess in pressure at the condenser.
Lower head pressure is better for compressors.

[dewax-chiller]

What type of expansion device do you use? Some require a considerable head pressure to feed while others do not need anywhere near as much.

expansion device? as in suction trap before compressors? sorry I'm not familiar with that terminology. our compressors are usually at a 13-15# suction pressure. and discharge, head, and receiver pressures are always equalized.

[lana]

Hi there,

You are talking about liquid circulation system not DX (Direct expansion) system, at least I think so.

Correct head pressure depends on the design and selection of the equipment.

If you are talking about liquid circulation system (you have ammonia liquid pump) then the ammonia guys would help you the best.
Cheers

[dewax-chiller]

no pump to move ammonia. the compressor is pulling and pushing the nh3 through the system. this is becoming the issue. no one uses a gravity flooded recirculation nh3 system with a shell and coil intercooler anymore. i suppose i should have described the system better in the thread intro.