Chapter 3: Air Conditioning Processes

AIR CONDITIONING PROCESSES

Introduction. The conservation of mass and energy is used in the study of air conditioning processes. Analysis of air conditioning processes is required for maintaining proper temperature and humidity in living space such as residential, commercial, and industrial facilities. The basic processes are as follows:

1. simple heating and cooling processes;

2. cooling with dehumidification;

3. heating with humidification;

4. adiabatic mixing of two air streams; and

5. evaporative cooling.

These air conditioning processes are represented in Fig. 3-1. Simple diagrams of the psychrometric chart are shown in Figs. 2-5 and 2-6.

Figure 3-1: Fundamental airconditioning processes

Simple Heating and Cooling ( W = constant). In some heating applications, air is heated without moisture being added. An example of this process is a heat pump with heating coil and no humidifier system. In the case of a simple cooling process, in some chilled water cooling applications air can be cooled without condensation. Figs. 3-2 and 3-4 shows schematics of simple heating process and a simple cooling process, respectively. The simple psychrometric diagrams of these processes are shown Figs. 3-3 and 3-5 respectively.

Figure 3-2: Schematic of simple cooling process (sensible cooling)

Figure 3-3: Psychrometric diagram of simple cooling process

Figure 3-4: Schematic of simple heating process

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