Condensation Problem in Electric Room

Instead of air conditioning, try dehumidification instead.

We need to control temperature also because you know drives when running at full swing produces a lot of heat and at the same time out side atmospheric temperature is also mostly around 38 ~40'C.

Can we use both dehumidifier and air conditioners at the same time?

Don't the cool the room as cold and use a dehumidifier too.

<...out side atmospheric temperature is also mostly around 38 ~40'C...>

Are there any clues as to where in the world these postings originate from, please? It would be helpful and save a load of time!

There exists a spray on foam insulation that I used to prevent just the same kind of problems in a large corregated panel type steel building for public meetings. The building was actually designed for agricultural use. The product is a closed cell foam. It is sprayed on the inside of the building. There are also foam insulations that are sprayed on the roofs of mobile homes exterior.

TMF

I would first check for any water drains in or around the room. Then look for any openings that allow humidity to enter. Outside of that cooling the room too low will draw moisture.

also I would trace for any lines the may carry fluid thru the room that could be drawing moisture as the heat from the fluid lines transfers.

I once installed an old carpet pad in a room with part of it passing under a door and it acted as a wick to remove moisture. It worked had to replace it a few times but it worked.

I would suggets the following"-

1) Since the air is humid if you turn off AC, naturally water droplets will be formed. So it is qute natural.Also it seems your AC is insufficient for the room.

2) I also supect the leakages in the room.It has to be closed.

3) You can install normal 3-phase exhaust fans for ventilations and see teh effect. You can control temperature in this way.

4) Recheck the purpose of AC installation. your problem is humidity and not the temperature.

5) You can try to blow ghot air through steam coil heating and put an exhaust.

AC will also de-humidify at the same time.

Stop large quantities of outside air getting in (but be careful if people are working in there that they get enough oxygen....).

Correct any leaking pipes etc...

Pipe the water from the AC unit to outside of the compartment....

Only cool enough to allow equipment to function fully, do not over cool.

I HAVE CONSTRUCTED A LOT OF STEEL BUILDINGS SO I HAVE HAD TO ACCOUNT FOR THE CONDENSATION YOU ARE SPEAKING ABOUT. It only takes a 14 degree difference in ambient tempreature from one side of metal to the other to cause condensation to show up on the cool side. Significant air circulation, and the input of warm very dry air is the way climate control storage buildings handle that issue. Substantial air conditioning will also work but is more expensive unless you need to provide cooling anyway. No other way around this problem exist to my knowledge.

TMF

Pressurize the room to keep the humidity out; presently you have lot of penetration in the room to draw hot & humid air into the room. Do not put exhaust as it would throw out the cold air & draw in the hot air. Lastly, seal the room to ensure no openings to draw in the hot air and add insulation to your room (walls, floor, ceiling, etc). If there are pipes going through, insulate them.

There is no cheap solution; as somebody suggested earlier, pressurize the control cabinets with dry instrument air, make sure you have made the cabinets air tight.

Good luck

Your AC system is probably too powerful for those cooler damp days. A dehumidifier would help but would reject heat in the room. Install a smaller AC unit in addition to the larger one. Set its thermostat a few degrees lower than the larger unit. The small AC will run most of the time removing a lot of humidity and heat from the drives. When the very hot days or large loads will kick in, the larger AC will turn on to help. This will save you some electricity and improve the temperature regulation while doing a better job at reducing the humidity.

Also. Avoid blowing very cold air directly at the electrical cabinets.

Air conditioning is one of the best methods of removing moisture/humidity from the air in any location. Chilled air dryers are the most efficient means of removing entrained moisture from any gas.

The vapor will condensate heavily on the evaporator and if the AC is properly sized for the area being cooled, there should be little ambient humidity.

If the AC is verified to be of the correct size, you need to look at the economizer section control setting (if present) and adjust the fresh air inlet so as to restrict the "make-up" air to 10% or less (depending on human occupancy).

If there is not an economizer or "fresh-air" inlet on your AC unit, and you are recycling 100% of the air, then you need to seal the room to prevent outside moisture-laden air from entering the room and limit access (keep the doors & windows closed).

Also be sure that any and all moisture has adequate drainage so that it doesnot get trapped in the room. Vent all drains directly to the outside and not to an open drain inside the room.

How well is the room insulated? Perhaps better insulation could negate some of this condensation?

I don't think you can pressurize the electrical room unless the room is a separate room within the mechanical shelter on his crane. I presume Sved is talking about a container crane which usually has wire cables protruding from the ceiling for boom hoist and depending on the type, out the bottom for trolley and main hoist and may have diesels running in the space for power.

If the room is separate, dehumidifiers might be the answer providing the power is left on the crane. 24 degrees C is pretty low in this type of application and has been suggested by another poster that the temp is raised; surely the manufacturer has provided the optimal operating temp to protect the equipment from overheating.

If the power is certain to be turned off, how about solar powered cabinet fans?

He also mentioned that he has two AC in the control room; if the room has openings for cables etc, it is pretty wastefull to cool it. The other suggestion was to pressurize the control cabinets. Refer to ISC (company) for enclosures which are air conditioned or pressurized. This may be a good application for such encl.

Hope it helps.

JMSK

Good day Sir!

You are right we have container cranes commonly known as STS or QC. Machine room is separate which consists of motors, gearboxes, drums etc. Electrical room is adjacent to machine but completely isolated. There is no diesel as the input power is 11kV,1650kw coming from a separate power house via cable reel.

I agree with shockhiscan, look for anywhere water, or it's vapor can enter the room. An open drain, a conduit from another area, even an unsealed doorway. Nature seeks balance, so humidity will do all it can to enter a dry room. Consider a double entryway to control the air exchange when someone enters the room. Spray foam in conduits, run drain pipes outside, try to maintain positive pressure in the room. Cooler air is contracting and drawing moist air from outside, have it pass over the evaporator fins to dehydrate first. Check the drain from the evaporator, it should have a trap to keep moist air out. The drain from the evaporator must have enough drop to keep negative pressure in the evaporator area from pulling drain water back. A dusty filter can cause enough pressure drop in the evaporator area to actually pull water up the drain, and the pan under the evaporator will overflow.

I also agree that a little dehumidifying running all the time is much better than off-and-on large cooling, which just makes all your components cold plates.

You still need some AC in the space to keep your modern electronics happy. Also, it makes it a lot easier to troubleshoot the equipment when you don't have sweat rolling down your nose. Machinery houses get freaking hot, trust me I know. The ones I worked on in SC were not air conditioned and it was no fun in 100 degree plus heat. Plus back then, we troubleshot everything hot.