how to cool a 2000kva transformer?

[al]

Hi all

need to provide a solution for a customer, they have the above trafo in an enclosed switchroom, there is currently no ventilation, the last trafo burnt out and now cooling has become imperitive

Has anyone any ideas on how to calculate the heat load for this?? was thinking of fresh air only but if the ambient goes to 25 or so will this still cool the room enough??

Thanks for the help
Al

[Brian_UK]

You need to get information relating to the design operating conditions of the transformer.

Personally I would have thought that providing a good air ventilation system should be sufficient - but don't take my word for it.

[C Bagtas]

For me you need to install an airconditioning unit. in my experiences in middle east, i maintained switch gear, even winter my my a/c unit is working so that nothing will trip in switch gear.

[al]

Thanks lads

Figure i need an a.c unit, but how big?? i fitted a 14kw temporarily and it just won't do it Any ideas??

Al

[eggs]

from memory you will also need a filtered fresh air supply to creat positive pressure in the switch room.
So that when you open the door no dust gets in.

cheers

eggs

[US Iceman]

There is probably a maximum temperature rise for the transformer. This data may be listed on the nameplate.

The cooling load required is based on the transformer capacity and the efficiency of the transformer.

If the transformer capacity is 2000 kva and it is 85% efficient, the 15% difference is generated as heat that must be removed. (this is for example only, don't use these numbers! The principle does apply though as it should be similar to motor heat load for ventilation purposes)

You need to get information relating to the design operating conditions of the transformer.

I agree completely. I would call the transformer manufacturer and ask them how much cooling is required to be safe.

Most of the switchgear rooms I have been in are just cooled by ambient air. However, if the ambient air temperature is too high then AC is the way to go.

It may be cheaper to install an AC system than the duct work and fan system? It all depends on where the room is.

[Renato RR]

The US Iceman have good logic on load calculation for the room.
I would recomed Hiross industrial air conditioner for such room.It have free coling and if the fresh air is enought for coling the compressor wouldnt start.Great seaving of energy and if compressor burn out or anithing go wrong you alvays have fresh air for security.

Renato

[al]

Thanks for the replies, plenty food for thought. i fancy the hiross concept while i wait for the trafo company to call me!!

Al

[Peter_1]

http://www.ecmweb.com/mag/electric_g..._transformers/

[rbartlett]

My old company used to do quite a few of these things

We just wacked in some big ceiling mounted splits as and when.....just the J.O.B

http://www.twyverswitchgear.co.uk/switchrooms.html

I believe they still do the work for them -so that must work as these containers go all round the world....

cheers

richard

[al]

Lads

Thanks for all the replies, got info from the factory that a 2mva trafo has a total heat loss of 23kw, so i reckon a 40kw rooftop should cover this and the rest of the switch gear, and can also positively pressurise the room and use free cooling.

Does this sound ok to y'all???

Al

[US Iceman]

Hi Al,

My only comment to this would be the difference in capacity for the AC system versus the transformer heat load.

Since the heat load from the transformer is about 57% of the AC system cooling capacity will the AC system have capacity control to modulate the required cooling?

Otherwise, the AC system may experience short cycling due to the smaller heat load form the transformer.

Are there other transformers in the vault that can contribute to the overall heat load. The heat off of the other switchgear should be minimal.

[al]

Hi iceman,

there is a power factor correction system also which is nearly as bad as the trafo, but i'm looking at a York rtu with two stage cooling, but for 70% of the time i hope to use fresh air only.

Al