Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
A COMPARATIVE ANALYSIS OF THE THERMAL PERFORMANCE OF THE REFRIGERANTS R134a, R245fa, R407C AND R600a DURING FLOW BOILING IN A MICROCHANNELS HEAT SINK
Submission Author:
Hugo Leonardo Souza Lara Leão , GO , Brazil
Co-Authors:
Gherhardt Ribatski, Hugo Leonardo Souza Lara Leão
Presenter: Hugo Leonardo Souza Lara Leão
doi://10.26678/ABCM.COBEM2017.COB17-2631
Abstract
The present paper concerns a comparative study of the performances of the refrigerants R134a, R407C, R245fa and R600a during flow boiling in a 123x494 µm2 microchannels heat sink composed of 50 parallel rectangular channels. Experimental results for the heat transfer coefficient were obtained for footprint heat fluxes up to 310 kW m-2, mass velocities from 400 to 1000 kg m-2 s-1, liquid subcoolings at the test section inlet of 5 and 10 °C and saturation temperatures about 30ºC for R245fa and 26 °C for R134a, R407C and R600a. The experimental results for the refrigerants R134a, R407C and R245fa were extracted from previous studies performed by the group. From the analyses of the database, average effective heat transfer coefficients up to 10 kW m-2 °C-1 were found. The onset of nucleate boiling (ONB) was identified, in particular, the fluids R245fa and R407C presented the highest and lowest superheating necessary to trigger the boiling process, respectively. The refrigerants R600a and R407C presented the highest and the lowest heat transfer coefficients, respectively.
Keywords
Flow boiling, Heat transfer coefficient, Microchannels Heat sink
