one A.H.U for several rooms?

[gladstone]

hi guys
i want select one A.H.U for 4 rooms get following cooling loads 4,6.5,7,8.5 ton respectively for this case i get 2 questions:
1-what is the capacity of A.H.U cooling coil in this case ,what should i do ?
1-capacity of fan ?
i am sorry i am new in hvac so i am facing this problem,
articles ,will be appreciate .
thanks for every one help.

[BaldLoonie]

That's 26 tons of cooling. What is the use of the space? Any kind of zoning or VAV? Condensing unit outside or chilled water? What kind of heat?

[gladstone]

thanks boldloonie for your quick reply.
how can u get this calculation ,is there possible show me the equatons u used ?
is there important for your questions ? zonning or vav system , condensing unit or chiller ?
please can u clarify to me?
thank u vvmuch .

[valdelocc]

Gladstone,is going to be very hard for anyone to help you here. you need to provide more info. about your hvac plan by that I mean detais about the equipment,ducting,area mesuraments,etc. If you have a plan we could help you to improved it.

[Carnak]

Originally posted by gladstone
hi guys
i want select one A.H.U for 4 rooms get following cooling loads 4,6.5,7,8.5 ton respectively for this case i get 2 questions:
1-what is the capacity of A.H.U cooling coil in this case ,what should i do ?
1-capacity of fan ?
i am sorry i am new in hvac so i am facing this problem,
articles ,will be appreciate .
thanks for every one help.

Well you need to decide if this is going to be a constant volume or a variable volume system.

Are these loads you give the peak loads of each room? These peaks would not occur at the same time.

For a VAV system, you should be able to calculate the peak cooling load and therefore the peak air flow for the system. You would then select the cooling coil and AHU fan capacity based on this.

For constant volume there are a several options.

Sounds like there may be a library of books where you are working, read through a few of them, maybe start with the ASHRAE handbook series.

[ac/dc]

I would strongly recommend you hire a reputable hvac
contractor to look at this project and give you some options.

[docholiday]

I very much doubt that the load in the individual rooms in constant so I would certainly consider zoning or seperate systems, then once zoned you need to look at peak demand times for each and see when each zone has a peak and size the system properly. Abitrarily installing one 25 or 30 ton system on one zone in this set-up will likely lead to complaints and neverending hassles.

[gladstone]

hi friends
thanks for every one vvvmuch for this valuable helps tips .
now u open to me new door. i have got carrier handbook 1968 edition .i read it about this subject .but i can not get clear idea how can analyze the peak and part load graphically during day , month ?i understand imust used storage factor and diversity factor depend on the application.
when i size cooling coil capacity i must size it according part or peak loads?
really i need your help ?is there techanical articles
i am appressiate for u.

[marauderx]

Originally posted by gladstone
hi friends
thanks for every one vvvmuch for this valuable helps tips .
now u open to me new door. i have got carrier handbook 1968 edition .i read it about this subject .but i can not get clear idea how can analyze the peak and part load graphically during day , month ?i understand imust used storage factor and diversity factor depend on the application.
when i size cooling coil capacity i must size it according part or peak loads?
really i need your help ?is there techanical articles
i am appressiate for u.

1968 is too old, no matter which country you are in. It's a good basis for understanding, but do not design around what's in it.

The cooling coil will be sized to the peak load, and the coils, fins per inch, gpm, etc. should be carefully selected by someone with experience. The fan should also be done by someone with experience, as the pressure across the coil and in the ductwork will need to be calculated. The CFM must also be determined from the space use, and will really need the hand of an expert to determine whether you should go with 400 CFM/ton or up to 550, or whatever.

Lastly, I am appressiate for u2.