HVAC design for high altitude with standard psych chart
HVAC design for high altitude with standard psych chart
(OP)
Hello,
I am trying to determine how to use the standard psych chart in calculating the sensible and latent loads for a space. It is located in Salt Lake City, UT and will be a once through system.
I know that there will be a factor applied for the difference in air density ratios. If so I am assuming you read the numbers from the chart as if you were at standard conditions and apply it only to the following equations:
RSH = 1.08*Factor*CFM*Delta T
RLH = .68*Factor*CFM*Humidity Ratio
I would appreciate a little help with this.
Thanks in advance,
aumechengr
I am trying to determine how to use the standard psych chart in calculating the sensible and latent loads for a space. It is located in Salt Lake City, UT and will be a once through system.
I know that there will be a factor applied for the difference in air density ratios. If so I am assuming you read the numbers from the chart as if you were at standard conditions and apply it only to the following equations:
RSH = 1.08*Factor*CFM*Delta T
RLH = .68*Factor*CFM*Humidity Ratio
I would appreciate a little help with this.
Thanks in advance,
aumechengr





RE: HVAC design for high altitude with standard psych chart
RE: HVAC design for high altitude with standard psych chart
In the '90's I found many installations with incorrectly sized fan motors and coils from the old approach used in the '70's.
RE: HVAC design for high altitude with standard psych chart
SH = 1.1 x cfm x dT
LH = 4840 x cfm x dW
Now the correction for altitude is the constant x (P1/Pa)
(Page 30.13)
P1/Pa can be calculated as (1-((6.8754x10^-6)*Z))^5.2559
Z is altitude in ft.
This correction is only for altitude. If you use the sensible heat corresponding to the temperature, you can have precise factors.