Two-phase refrigerant maldistribution in the vertical header and its effect on the heat exchanger performance as evaporator in heat pump mode

Yang Zou, Hanfei Tuo, Predrag Stojan Hrnjak

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The vertical header is a usual feature of outdoor heat exchanger of the residential air-conditioning system, typically a multipass microchannel heat exchanger. When operating in heat pump mode, it functions as an evaporator. In such a system, refrigerant maldistribution in the header can deteriorate the performance of the heat exchanger. The objective of study in this paper is the adiabatic upward flow of the refrigerant in the second pass vertical header of microchannel heat exchanger and its effect on distribution. R410A is circulated into the header through the microchannel tubes (5 or 10 tubes) in the bottom pass and exits through tubes (5 or 10 tubes) in the top pass. Three circular headers were explored, each with the microchannel tubes inserted to half depth. The best distribution is found at high flow rate and low quality. The distribution is affected by the flow patterns in the header as well as axial momentum. A distribution correlation, obtained based on the flow rate measurement in each tube, was then incorporated with a microchannel heat exchanger model. The simulation results quantified the capacity reduction of the 2-pass microchannel condenser due to the refrigerant maldistribution.

Original languageEnglish (US)
Title of host publicationASME 2012 International Mechanical Engineering Congress and Exposition, IMECE 2012
Pages1823-1832
Number of pages10
EditionPARTS A, B, C, D
DOIs
StatePublished - Dec 1 2012
EventASME 2012 International Mechanical Engineering Congress and Exposition, IMECE 2012 - Houston, TX, United States
Duration: Nov 9 2012Nov 15 2012

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
NumberPARTS A, B, C, D
Volume7

Other

OtherASME 2012 International Mechanical Engineering Congress and Exposition, IMECE 2012
CountryUnited States
CityHouston, TX
Period11/9/1211/15/12

ASJC Scopus subject areas

  • Mechanical Engineering

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