NDEngineer
Mechanical
- May 25, 2004
- 12
Forgive me for my ingnorance, but I have what may be a elementary question regarding heat gain and DX cooling. I am cooling a telephone equipment room with the following loads:
Transmition and Solar Loads: 5500 BTU/hr
Equipment Loads: 20500 BTU/hr
~300 CFM F.A.: 9200 BTU/hr (sensible) 6000 BTU/hr (latent)
Total sensible cooling: 38000 BTU/hr (w/ supply fan load)
Total coil load: 44800 BTU/hr
OK, the problem is that the space is to be maintained at 65 deg F (O.A. design - 95 db, 74 wb). To keep the space at this temperature, the required CFM (~2500 assuming a leaving db temp of 55 db) is substantially higher than the rated CFM on the unit the owner INSISTS on using (1500 CFM for the 4 TON unit).
I'm not sure if the fan is direct or belt drive (I'm meaning to find out). IF it is a belt drive, can I just increase speed of the fan until it is able to give an output of 2500 CFM? Will the coil be able to keep up with this?
IF the fan is direct drive, would it be OK to oversize the unit (say a 5 TON w/ 1700 CFM)? Any other ideas?
Sorry for the long post, but I'm pretty lost as to what to do in this situation. Thanks in advance for any input.
Transmition and Solar Loads: 5500 BTU/hr
Equipment Loads: 20500 BTU/hr
~300 CFM F.A.: 9200 BTU/hr (sensible) 6000 BTU/hr (latent)
Total sensible cooling: 38000 BTU/hr (w/ supply fan load)
Total coil load: 44800 BTU/hr
OK, the problem is that the space is to be maintained at 65 deg F (O.A. design - 95 db, 74 wb). To keep the space at this temperature, the required CFM (~2500 assuming a leaving db temp of 55 db) is substantially higher than the rated CFM on the unit the owner INSISTS on using (1500 CFM for the 4 TON unit).
I'm not sure if the fan is direct or belt drive (I'm meaning to find out). IF it is a belt drive, can I just increase speed of the fan until it is able to give an output of 2500 CFM? Will the coil be able to keep up with this?
IF the fan is direct drive, would it be OK to oversize the unit (say a 5 TON w/ 1700 CFM)? Any other ideas?
Sorry for the long post, but I'm pretty lost as to what to do in this situation. Thanks in advance for any input.