What I determined (and this may not be exact but it gets the job done) was that if you multiply the humidity ratio time 7000 then you get the grains/lb. So what I figured out was that the humidity ration (lb/lb) was proportional to the grains per pound. If I knew those then what I needed to determine was my % Relative Humidity using the charts. I also could use the same equation to find my mixed air temperature. That gave me my mixed air humidity in grains per pound. Here is what I did and the problem I needed to solve. RE: Relative humidity and humidity ratio question.
Is there any way to look at the humidity measured in grains/lb and use an equation and maybe a chart of values to convert it to a Relative Humidity Ratio measured in % ? This all makes sense cause if I draw a line on the psyh chart between the points and then use the 80% mark away from the outdoor point I get the point that corresponds with what I jsut found. I also know that I can use the humidity as measured in grains/lb to find humidity:
AIR HUMIDITY RATIO CALCULATOR HOW TO
I know how to find the mixed air temperature: My split is 80% return air and 20% outdoor air. I have a portion of mixed air that is entering my evaporator. In doing this I would liek to use equations and data fro mcharts as much as possiable so that I do nto need to reference the psychrometric chart - I want to keep the model I am building dynamic and easy to use. I am trying to set up a program on excel to look at air conditioning loads and what not.