Oct 22, 2009 #1 waerdamageman Structural Oct 22, 2009 1 how do i get the grains per pound out of tempiture and relative humidity. i need it to create a excell spread sheet. i use it for structural drying.
how do i get the grains per pound out of tempiture and relative humidity. i need it to create a excell spread sheet. i use it for structural drying.
Oct 22, 2009 #2 IRstuff Aerospace Jun 3, 2002 44,504 grains of what per pound of what? I assume that's water, and air? The RH tells you the percentage of water relative to the saturation level at the temperature stipulated. There are equations and articles all over the internet about this. TTFN FAQ731-376 Upvote 0 Downvote
grains of what per pound of what? I assume that's water, and air? The RH tells you the percentage of water relative to the saturation level at the temperature stipulated. There are equations and articles all over the internet about this. TTFN FAQ731-376
Oct 23, 2009 #3 trashcanman Mechanical Jan 4, 2002 470 See ASHRAE Handbook of Fundamentals, Psychrometrics. There are equations in there to calculate what you need. Upvote 0 Downvote
See ASHRAE Handbook of Fundamentals, Psychrometrics. There are equations in there to calculate what you need.
Oct 24, 2009 #4 KiwiMace Mechanical Feb 2, 2006 1,012 In ASHRAE fundamentals there is an empirical formula for water vapor pressure as a function of temperature only (2009 IP version Chap 1.2 Eqn.6). Then you need to use the following and be consistent with your units: W = 0.62198.RH/100.PVsat ____________________ Patm - RH/100.PVsat Multiply by 7000 for grains. This appears to rely on the assumption that the RH is the same as degree of saturation, which is a minimal error for most applications. Should do the trick. Upvote 0 Downvote
In ASHRAE fundamentals there is an empirical formula for water vapor pressure as a function of temperature only (2009 IP version Chap 1.2 Eqn.6). Then you need to use the following and be consistent with your units: W = 0.62198.RH/100.PVsat ____________________ Patm - RH/100.PVsat Multiply by 7000 for grains. This appears to rely on the assumption that the RH is the same as degree of saturation, which is a minimal error for most applications. Should do the trick.
Nov 4, 2009 #5 sridhar1312 Mechanical Jun 1, 2009 58 You can get the details from psychrometric chart. Upvote 0 Downvote
