PERFORMANCE ANALYSIS OF EAHE FOR DIFFERENT PIPE GEOMETRIES AND...
ABSTRACT
The study investigates the thermal performance of Earth air Heat Exchanger (EAHE) for heating and cooling modes
under Indian climatic conditions. A 3-dimensional, double precision computational fluid dynamics (CFD) model is developed
in Ansys FLUENT v15.0 under steady conditions for three different pipe materials and four different pipe geometries. The
pipe geometries considered for the study are round; square; triangle and triangular-corrugated and the pipe materials
considered are Aluminium and Steel. This paper aims to find the appropriate pipe geometry and pipe material to obtain
optimum temperature variation for thermal comfort. The impact of ambient temperature, mass flow rate, Reynolds Number,
Prandtl number and Nussult number were studied. Results show that as the length of the pipe increases the temperature at the
outlet decreases during cooling mode and vice versa. The maximum temperature drop observed is 12.05K during cooling mode
and 16.65K during heating mode for triangular-corrugated pipe. This was observed by varying the mass flow rate and without
considering the pipe material. Whereas Reynolds number decreases with increases in the temperature drop for corrugated
pipe irrespective of the modes and pipe material. The maximum temperature drops around 13.62K at Reynolds number
38.664. Furthermore, out of the two different pipe materials the maximum temperature drop was observed for corrugated pipe
in case of aluminum pipe material when compared with steel at 2m/s. It can be concluded that corrugated aluminum pipes can
be used to get optimum temperature drop for better thermal comfort. Moreover, as the mass flow rate increases, the outlet
temperature increases during cooling modes and vice versa during heating mode irrespective of the pipe materials and pipe
cross sections.
