My Question is, what is the correct way to calculate outdoor air load from ventilation.
Problem 519 Givens: Qsens = 90,000 BTU/hr; Qlat = 40,000 BTU/hr; Supply air= 3,600 CFM @ 55 db. Room temp = 78degF db/ 45%rh; Outdoor air = 700cfm 92degF db/76degF wb.
The problem ask for total load. I know you need to find the load from ventilation and add it to the other given loads. However, is it 4.5XcfmX (houtdoor air -hsupply)? Or is it 4.5XcfmX(houtdoor air - hroom air)?
Problem 59 in the "Mechanical PE Sample Exam, 2nd Edition, by Michael Lindeburg says that OA from ventilation is equal to 4.5XcfmX (houtdoor air -hsupply). However problem 519 in the 2001 NCEES says it's the other.
Problem 519 Givens: Qsens = 90,000 BTU/hr; Qlat = 40,000 BTU/hr; Supply air= 3,600 CFM @ 55 db. Room temp = 78degF db/ 45%rh; Outdoor air = 700cfm 92degF db/76degF wb.
The problem ask for total load. I know you need to find the load from ventilation and add it to the other given loads. However, is it 4.5XcfmX (houtdoor air -hsupply)? Or is it 4.5XcfmX(houtdoor air - hroom air)?
Problem 59 in the "Mechanical PE Sample Exam, 2nd Edition, by Michael Lindeburg says that OA from ventilation is equal to 4.5XcfmX (houtdoor air -hsupply). However problem 519 in the 2001 NCEES says it's the other.