The processes can now be plotted on a psychrometric chart as shown below.
1. Points O, M, P and R can be shown on the chart.
2. Join points O and P and P and R.
3. Find the mix point M
The line measures 81mm long.
81 x 0.8 = 65 mm , the distance from point M to R is 65mm.
4. The room ratio is 0.76 from previous calculation. Draw RRL.
5. Find the supply air dry bulb temperature by calculation