Baltimore (NH3) Hybrid condenser HXC

[virk]

Hello!

We are going to install 3 hybrid condensers HXV for condensing NH3. These are equipped with one (dry) finned tubes section at the top and with a (normally wetted) tube section below. During cold periods main load shall be covered by the dry section. During hot periods the normal wetted section shall take the total load.

The connection of both sections is not done by supplier but will be done by ourselves. Supplier suggests to connect both sections in serial; NH3 gas enters at the top, outlet of this finned tube section is connected to wet tube section gas inlet and outlet of this is connected to vessel.

I prefer to connect both sections in parallel. (BTW: We know about principal routing of refrigerant pipes especially at parallel condensers)

What do you think of it? Parallel or serial and why?

Kind regards

virk

 

[TXiceman]

Pipe them in series as suggested by BAC. Enter the dry coil first and run it as a desuperheater and then the wet coil. When running the wet coil, you will use the top coil to help with plumb abatement (ie. the vapor cloud which many cities are finding to be objectionable.

One company I worked for designed several evaporative cooled units with the top abatement coil.

Ken

Ken
KE5DFR

 

[sterl]

Top abatement interesting term; Niagara's standard was this, which they termed Desuperheater coils....We used them frequently in Cold Climates piped just as TXi indicates. They were notorious for collecting dirt, dust etc. and growing stuff in the summer time: Warm dirt plus warm moist air and a few loose seeds, and the foliage was far ahead of the "natural" stuff....

We eventually reworked some of these so a select portion of the finned section, over just the center 25% of the wet coil, was incorporated into a "low flow" distribution pan, which kept the water warm and let it trickle down the center-only of the wet coil...These were the only condensers we could apply any water to at outdoor temperatures of -10 F. and the scale scenario was not as bad as you might anticipate.

 

[virk]

Thank you both for your comments!

Main problem was a total pressure drop of 300 mbars of the condenser if it was connected in series. BAC now has connected the top coil in parallel, total pressure drop now is now said to be less than 100 mbars. I think we can connect them in series now, so as BAC advises.
BTW: We do not need the top coil for desuperheating purposes: ammonia gas already enters with about 40°C into the condenser.

Thanks to all who have helped!

Kind regards

virk