OPTIMIZATION OF THE GEOMETRIC PARAMETERS OF A TWISTED TAPE FOR THE INTENSIFICATION OF HEAT TRANSFER IN SOLAR COLLECTOR

Resumo

Large is the amount of thermal energy that needs to be supplied for the heating of water in
domestic or industrial environments, whether by burning gas, biomass or by direct use of electricity.
Today, these traditional methods have been resisted in their expansion in response to the inexorable
increase in demand. In this sense, solar energy has emerged as one of the most attractive renewable
sources for this type of application, requiring, in this way, the continuous technological development
of solar collectors more efficient thermally that meet the application requirements. Thus, the objective
of this paper is to perform the numerical simulation of the process of intensification of heat transfer in
a flat plate solar collector with active system and indirect circulation of single-phase working fluid,
through the device known as Twisted Tape, down Reynolds number 600. The geometric parameters of
the twisted tape subjected to the Direct Optimization approach are: Twisting tape pitch (P), length (L),
Translate (T) and twisted tape radius (R1 and R2). The analysis of the optimization process associated
to the heat transfer intensification performance and the associated pressure loss were analyzed through
computational modeling in ANSYS and ESTECO ModeFrontier software. The main results of this
project indicate that the optimization process using the Genetic Algorithm method led to a geometry
with asymmetric radius for both the Reynolds number evaluated, yielding significant results
corresponding to a global heat transfer increase of approximately 170 %, while the symmetric tape
with twist ratio 4 (R4) increased by 52 %. Evaluating the flow loss, the optimized tapes again showed
better performance as they increased the pressure loss by about 248 %, while the symmetrical (R4)
tapes increased by 268 % for Reynolds 600.