*3.3.1 Straight pipe heat exchanger for earth to air*

Heat exchanger for the earth to an air of straight pipe length, diameter, and velocity 20 m, 0.15 m and 2 m/s respectively have been used for analysis. The ambient temperature of the Bikaner region is 47.6°C is used for the analysis of heat exchanger for the earth to air. There are eight temperature sensors (Tinlet, T1, T2, T3, T4, T5, T6 and Toutlet) are inserted in a pipe at equal distance of 3.34 m to find out temperature at a different section. Straight pipe heat exchanger for the earth to air, air temperature falls from 47.60 C to 28.340 C.

**Figure 11** represents the contour plot of temperature distribution in the air. The fluid flow analysis of a straight pipe heat exchanger for the earth to air is evaluated by using the computational fluid dynamic fluent model for cooling mode for the hot and dry climate of the Bikaner region.
