Análise do conforto térmico do Museu do Universo (Planetário da cidade do Rio de Janeiro)

Abstract

This work aims to obtaining the velocity and temperature fields inside the Museum of the Universe (Planetarium of the Rio de Janeiro city) by Computational Fluid Dynamics with the commercial software Ansys Fluent, and then calculate the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) indexes of termal comfort at 10:28 am, 12:08 am and 3:33 pm on May 12, 2014. The computational domain was generated by extracting the indoor air from the building geometry generated in SolidWorks@2017. The boundary conditions were no slip on all walls and prescribed velocity on air conditioning diffusers. Data for temperature boundary conditions came from previous experimental work. The entire envelope received a prescribed temperature except for the north face of the glass cover with prescribed heat flow. The prescribed heat ow was also inserted on the ground and first floors, assuming a uniform distribution of heat produced by the visitors. The Fluent default meshing assisted to generate the polyhedral mesh with 1,444,195 elements, refined in the regions of interest. The mesh test was performed for the temperature in a vertical line in a central position. The incompressible steady ow was modeled by the Reynolds-Averaged Navier-Stokes equations (RANS) with the turbulence model SST k-w, by the Finite Volume Method with the pressure-based solution and coupled algorithm. Numerical convergence was assured through the mass balance residual analysis. Comparing the numerical results with the experimental ones from previous work, for the worst-case, the average of temperature absolute differences at 13 points was 0.87 ºC with a root mean square error of 4.75%. The average temperatures in the horizontal planes at 1.5, 4.5, 8, and 12 m at 12:08 h were respectively at 22.1, 22.2, 24.1, and 43.9ºC, very close at other times, except at 12 m at 10:28 h at 33.2ºC. The results demonstrated the ability of the air conditioning system to develop termal comfort between the ground floor and the ceiling of the 2nd floor, even when the later is turned off, aided in this condition by the thermal stratification of the air observed in the dome region, caused by local stagnation. The operation of the air conditioning on the 2nd floor provided a reduction of 1.5 and 3ºC in the average temperature, respectively at 8 and 12 m, but that also did not prevent air stagnation in the domus.