ABSTRACT
This chapter describes the psychrometric processes of heating, mixing, cooling, dehumidification and humidification. These processes are fundamental to air conditioning systems. The chapter details example calculations of conditions and complete processes. The properties of humid air are introduced and the use of the CIBSE psychrometric chart is thoroughly described in logical and manageable steps. Worked examples are used to demonstrate the calculations needed to find the physical properties of humid air. The use of sketch charts is introduced for explanatory purposes and for use during preliminary design. It is easier to use a freehand sketch than to be limited by the rigour of plotting exact locations. Precise data can be subsequently plotted onto a full size chart. There are computer programs to calculate and plot psychrometric states and lines. The chapter explains calculation and fined the dew point temperature of air and dry and wet bulb air temperatures, moisture content, percentage saturation, specific enthalpy, specific volume and density.
