Experimental evaluation of internal heat exchanger influence on R-22 window air conditioner retrofitted with R-407C

Abstract

a De part ment of Me chan i cal En gi neer ing, Gov ern ment Col lege of En gi neer ing, Sa lem, In dia b KSR Col lege of Tech nol ogy, Thiruchengode, In dia Orig i nal sci en tific pa per UDC: 697.97:66.045.1The per for mance of one ton of re frig er a tion win dow air con di tioner work ing with R-22 and retro fit ted with eco friendly al ter na tive re frig er ant R-407C is ex per i mentally in ves ti gated An in ter nal heat exchanger is also added to the same air con ditioner to pro vide liq uid over feed ing op er a tion. When retro fit ting the R-22 sys tem with R-407C, the co ef fi cient of per for mance is found to drop by 7.28%, how ever when in ter nal heat exchanger is in cluded the per for mance is im proved. It is observed that the in clu sion of in ter nal heat exchanger has in creased the co ef fi cient of per for mance by 5.86% when run ning on R-22 and 6.18% when run ning on R-407C, un der the given con di tions In tro duc tionGlobal con cern over ozone de ple tion and global warm ing have re sulted Mon treal and Kyota pro to cols, re spec tively, ac cord ing to which , the use and pro duc tion of chloro fluorocarbons (CFC) and hy dro chloro fluoro carbons (HCFC) have to be ceased in all over the world by the year 2010 and 2030, re spec tively. The en vi ron men tal prob lems caused by CFC and HCFC have been en cour ag ing en gi neers and re search ers to de velop new al ter na tive re frig er ants with highly ef fi cient ma chines which have the ca pa bil ity to re duce en ergy con sump tion [1]. It has been re ported that R-407C is a close match to R-22 with re spect to en ergy ef fi ciency and other per for mance pa ram e ters such as com pres sor dis charge tem per a ture and pres sure [2,3]. R-407C is the blend of R-32, R-125, and R-134a that has prop er ties sim i lar to R-22 (tab. 1). New sys tems built with R-407C must have polyolester (POE) lu bri cants, and retro fit ted R-22 sys tems would need the re sid ual oil flushed with POE. Yang et al. [4] have used re frig er ant mix tures whose per for mance is close to that of R-22. Jabaraj et al. [5] have re ported that HCFC 407C/HC blends are su pe rior to R-22. The ex per i men tal in ves ti ga tion, on the per for mance of R-407C un -

Condensation Heat Transfer of R-407C in Helical Coiled Tube Heat Exchanger

“…Yousef et al [20] analyzed the comparative performance of the four refrigerants: R-22, R-134a, R-407C, and R-410A, as alternative cooling fluids in a condenser in a steam power plant. Vijayan and Srinivasan [21] experimentally investigated the performance of R-22 and R-407C in a window A/C system that was originally charged with R-22 but later charged with R-407C. They found that the coefficient of performance increased, and the power requirement and pressure ratio of the compressor were reduced.…”

Laminar convective heat transfer for in-plane spiral coils of noncircular cross sections ducts: A computational fluid dynamics study

“…This study revealed that circular tubes develop a secondary flow when the Dean number exceeds a critical value. Since then several experimental [4][5][6][7][8][9][10] and numerical [11- 16] studies have been conducted in attempts to examine the transport phenomena in the spiral tubes. Most of these studies deal with spiral ducts with the typical cross-sections being circular or rectangular.…”