Journal of Engineering Sciences

Author(s): Nogueira E.

Affiliation(s): Department of Mechanics and Energy, State University of Rio de Janeiro, R. São Francisco Xavier, 524 Maracanã, Rio de Janeiro, 20550-013 Brazil.

^*Corresponding Author’s Address: [email protected]

Issue: Volume 8, Issue 1 (2021)

Dates:
Received: December 9, 2020
The final version received: April 24, 2021
Accepted for publication: May 1, 2021

Citation:
Nogueira E. (2020). Applying the concepts of efficiency and effectiveness to analyze the influence of the number of passes in the shell and tubes condenser thermal performance. Journal of Engineering Sciences, Vol. 8(1), pp. F1–F10, doi: 10.21272/jes.2021.8(1).f1

DOI: 10.21272/jes.2021.8(1).f1

Research Area:  CHEMICAL ENGINEERING: Processes in Machines and Devices

Abstract. The work analyzes the influence of the number of passes in a shell and tubes condenser heat exchanger, with an inlet pressure of R134a refrigerant in the shell equal to 1.2 MPa. The fluid that circulates in the tubes is water or water-based nanofluid with a fraction of aluminum oxide nanoparticles (Al₂O₃), and the methodology used subdivides the heat exchanger into three distinct regions: the overheated region, the saturated region, and the subcooled region. The main parameters used to analyze the thermal performance of the heat exchanger were efficiency and effectiveness. Efficiency in the superheated steam region is close to 1.0. There is scope for increasing thermal effectiveness, which can be improved with more significant passes in the tube. The saturated steam region process is efficient for lower mass flow rates of the fluid in the tube, but it is ineffective. However, it is highly effective for high mass flow rates. There is ample scope for increasing effectiveness in the subcooled region. Still, the fluid inlet temperature in the pipe and the work refrigerant pressure are the limiting factors for greater heat exchange in the subcooled region.

Keywords: heat exchange, refrigerant, tube condenser, thermal performance.

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