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.
I would treat this as a chilled water system and use primary-secondary pumping. Have a pump for each item to be cooled, thermostatically controlled. The whole system should be at least equal to the entire load + a safety factor to account for fouling. That way, If a pump comes on, the other...
If I were the Sprinkler Contractor, I would be leery of accepting your sizing of the main. The Contractor is usually responsible for the entire piping system, from the tap on the water main to the last fire inspector connection.
You see if your main size is too small, the Sprinkler Contractor...
You had better inform the client (in writing) of your intention, so he/she/it cannot come back and bite you. Ask for confirmation that they received your letter.
In addition to problems pointed out by previous posters, the 10T unit will NOT BE ABLE to control humidity in the space due to short cycling. The WB temp in the space will rise well above 50% if the space is occupied.
You want the cooling coil to run longer, to wring out the moisture.
Sorry...
