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i want to know duct size calculation of acmv installation. View All
Eg.Our capacity of CU(out door unit) is 67.8kw.we will use 8 fcu (indoor)units.fcu 1 is will use 2.2kw,fcu 2 is 7.1kw and fcu 3is 14kw and then fcu 4 is 14kw ,fcu 5 is 11.2,fcu6 is 5.6kw,fcu7 is 5.6 and fcu8 is 5.6.please give me answer duct size of each fcu unit.please give me general formula for duct calculation.can i need chart for calculation?if need say me chart name.

6 years ago - 7 months left to answer. - 2 responses - Report Abuse
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You need to get an A.S.H.R.A.E manual for the charts on this.

6 years ago


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rahul gopinath
BTUh = 1.08 CFM ( T2- T1 )
This is the basic sensible heat formula for determining cooling air flow to a space. One KW = 3415 BTUh or British Thermal Unit per hour.
Since nothing else was mentioned I will assume that the cooling load is all sensible, that is, there is no latent heat, or humidity to be considered.
A " CFM " is a cubic foot of standard air per minute.
Standard air is dry, has a density of 0.075 pounds/cu ft and a specific heat of 0.24 btu/lb/f change in temperature.
The temperatures are : T1 the cooling air entering the room, T2 the air returning from the room. These are Fahrenheit deg. and F = 1.8 C + 32
Often a temperature rise for the cooling air of about 18- 20 F deg is assumed.
You can use this information to calculate the total air flow and the flow needed to each of the eight rooms. We will suppose that the supply air ducts are well insulated.
You can start calculating the volumes now. I will return with an edit for information regarding sizing the ducts w

6 years ago


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