TY - JOUR

T1 - Flow boiling of R134a and ammonia in a plate heat exchanger

AU - Djordjevic, E.

AU - Kabelac, S.

N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2008/12

Y1 - 2008/12

N2 - This paper presents experimental results on evaporation heat transfer for flow boiling of ammonia and of R134a in a chevron-pattern corrugated plate heat exchanger (PHE). The measurements enable the evaluation of a quasi-local heat transfer coefficient along the plate, which in turn allows discussing the two-phase distribution and the heat transfer mechanism during evaporation in a plate channel. The saturation temperature varied between 268 K < TNH 3s < 283 K (3.55 bar < pRs < 5.73 bar) for ammonia and 265 K < TR 134 as < 283 K (2.157 bar < pRs < 4.14 bar) for R134a. The heat transfer coefficient is discussed in relation to the vapor quality, mass flux, heat flux and the type of refrigerant. The secondary fluid is a water/ethylene glycol mixture flowing in counter flow or parallel flow arrangement within the PHE. It is shown that the parallel flow case yields better overall performance than the counterflow case, and that plates with low chevron angle corrugations increase the evaporation heat transfer. Comparison with the limited data available from the literature shows good agreement. The Danilova equation and the Steiner boiling correlation are adapted to PHEs and show the need for further theoretical development.

AB - This paper presents experimental results on evaporation heat transfer for flow boiling of ammonia and of R134a in a chevron-pattern corrugated plate heat exchanger (PHE). The measurements enable the evaluation of a quasi-local heat transfer coefficient along the plate, which in turn allows discussing the two-phase distribution and the heat transfer mechanism during evaporation in a plate channel. The saturation temperature varied between 268 K < TNH 3s < 283 K (3.55 bar < pRs < 5.73 bar) for ammonia and 265 K < TR 134 as < 283 K (2.157 bar < pRs < 4.14 bar) for R134a. The heat transfer coefficient is discussed in relation to the vapor quality, mass flux, heat flux and the type of refrigerant. The secondary fluid is a water/ethylene glycol mixture flowing in counter flow or parallel flow arrangement within the PHE. It is shown that the parallel flow case yields better overall performance than the counterflow case, and that plates with low chevron angle corrugations increase the evaporation heat transfer. Comparison with the limited data available from the literature shows good agreement. The Danilova equation and the Steiner boiling correlation are adapted to PHEs and show the need for further theoretical development.

KW - Ammonia

KW - Evaporation

KW - Heat transfer coefficient

KW - Plate heat exchanger

KW - R134a

UR - http://www.scopus.com/inward/record.url?scp=55649111358&partnerID=8YFLogxK

U2 - 10.1016/j.ijheatmasstransfer.2008.01.042

DO - 10.1016/j.ijheatmasstransfer.2008.01.042

M3 - Article

AN - SCOPUS:55649111358

VL - 51

SP - 6235

EP - 6242

JO - International Journal of Heat and Mass Transfer

JF - International Journal of Heat and Mass Transfer

SN - 0017-9310

IS - 25-26

ER -