Why bother? Passengers will not be in the elevator long enough to complain. Remember, that the elevator cab is open to conditioned spaces at each stop.. Just delete the cab AC unit as it is not worth it (unless the client calls for it).
Sorry, but your sketch of the parallel pumps is fundamentally incorrect. If p1=p2 =p3, the flow =0. No pressure difference = no flow, The same goes for the series pumps.
To do it properly, will require a system of 5 non-linear equations and 5 linear equations, where flows and pressure points...
The writer did not say it was a chilled water system. He mentioned an Outdoor Unit, which sounds like a DX split system.
Regardless there IS condensation as he stated, not maybe.
Did the technicians also check the condition of the cooling coil? If it is clogged with dirt, that would increase...
Replace the old pump and replace with new. The old (how old?) has already probably reached its service life.
Now, start with new pump that you can be sure of.
Forget the door opening idea. Instead use a wall mounted motorized louver or a roof intake unit with a motorized damper. Provide burglar bars also. Also, sound alarm if louver is opened or closed without the fan running.
Sounds like a good case for primary-secondary pumping system, You flow the chilled water that the chiller(s) require in the primary loop, then on the secondary loop, you flow the diversified flow rate.
This should work.
You must start out with a VALID test and balance report. Most of the T & B reports I saw over about 50 years of design, few were correct. Get a report that makes sense. Then, do your analysis of the system. Off the top of my head, 57 Deg.WB will NOT DO MUCH DEHUMIDIFATION.
Evaporative systems work only in dry climates, like Nevada, Saudi Arabia, Iraq, Death Valley, etc. Trying it in SE Asia is a joke. An evaporative system CANNOT, REPEAT CANNOT REDUCE THE AMBIENT AIR RELATIVE HUMIDITY. By definition, it ADDS to the RH.
I think you need to hire a competent HVAC...
This is more of a physics problem, but deals with gas.
According to Astro Physics Scientists, a star is made when a huge cloud of H2 starts coming together by gravity. The gas packs in tighter and tighter, creating higher and higher pressure and temperature, till pressure/temperature reaches...
I would treat it the same as a fireplace chimney. Bldg. codes dictate how high about the roof and how far away (horizontally) the muzzle of the stack must be from a flammable surface and add your choice of a safety factor.
