Load Sizing for Air Conditioning

More information is needed:

What is the outdoor temperature?
What temperature do you want to maintain in the room?
How thick and what type of insulation is in the walls and ceiling?
Do the pumped fluids circulate entirely within the room, or do they go elsewhere?

1.outdoor temperature : 40 degree centigrate 2.temperature to maintain in room : 24 degree centigrate 3.walls thick: 20cm and ceiling: 20 cm 4.type of insulation :roof inulation fibre glass , wall : concrete , height of the room 6 meters the pump fluids go to a distance of 15 metre they not circulate within the room

150 tons should cover it

I'd like to hear that explanation.

How can you make a presentation to a paying customer on a subject about which you know nothing?

God forbid they should ask you a question.

How to Size an HVAC System | eHow

Room height is not given. Heat load calculation is the basic step top arrive the refrigeration load. Now days many software's are available. Or refer any basic air conditioning books to understand the heat load calculations. Sometimes thumb rules is used for checking purpose. It again depends upon many factors like outside & inside condition and type of ac system required etc. It is always better to seek assistance of HVAC consultant in your area and make your presentation in professional manner.

There is no simple answer to your question.That is why most countries require an examination and license to be able to install an air conditioning unit.

If you over size the unit, you will waste energy,because the unit will not run long enough to remove humidity from the room,requiring a lower set point to achieve comfort,and the temperature will oscillate needlessly.

If you undersize the unit,it will run constantly and never achieve set point.

It must be "just right' for comfort and economy.

Refer this problem to a qualified air conditioning expert in your local area.I say local, because there are local variables in climate that need to be taken into consideration,as well as the number of windows,site orientation,and number of cooling degree days,which are referenced from a chart.A local pro will have these memorized.

Good luck.

didnt you read any books for heating,ventilation, airconditioning and refrigeration?...please give some information how did you get job that need you have to explain to client about something that you dont know?

This, by the way, should have been posted in the MECHANICAL ENGINEERING forum, it is not an ELECTRICAL problem.

my condolences to your client.your outside air temp is 110F and you want to cool an industrial space with 20 foot high ceilings?, I hope you own a small power company. I suggest you you set up a ventilation system directly over some of your largest heat sources and scrub as much heat off of them as possible before paying huge money to have an air conditioner move that heat outside. the good news is if you double insulate the concrete walls with R-10 hard foam on each side with no air gaps you might get near an R-50 value on your walls.

I'm afraid I have to echo the sentiment of others...........get some pro help before you spend another dime on your heat calculation, you're over your head for the record, I'm a long time California licensed C-20 commercial air conditioning contractor, you're scaring me, you need to back off this job and let the big boys take over.