Not always is there complete freedom in where to place condensers, because the condensers should be close to the compressors that they serve, the walls of the machine room or other buildings may tend to obstruct air flow, and the condensers must be placed where their weight can be structurally supported. Within these limitations there are two major objectives to be kept in mind when siting the condensers. One is that the rate of air flow should not be restricted, or the reductions in capacity as discussed in Sec. 7.12 on capacity control will occur. The second precaution is to place the condensers so that there is a minimum of recirculation of discharge air from the same or other condensers entering a condenser. Recirculation results in a wet-bulb temperature of air entering the condenser that is higher than the ambient wet-bulb temperature.
Figure 7.19 shows several arrangements of condensers with Figs. 7.19a and 7.19b illustrating several problems while the placement in Fig. 7.19c offering a favorable placement. When the inlet of the condenser is close to a wall, as in Fig. 7.19a, the total air flow may be restricted. Furthermore some of the discharge air may be induced into the high-velocity air stream flowing down between the wall the condenser. In the arrangement of Fig.7.19b, the condensers appear too close to one another so that the condenser on the right draws some discharge air into its inlet. Manufacturers of evaporative condensers often recommended minimum spacing distances between condensers. The positioning shown in Fig. 7.19c provides ready access of ambient air to both condensers.