Compact heat exchanger designs for difluoromethane-activated carbon composites based adsorption cooling systems

Sai Yagnamurthy, Dibakar Rakshit, Sanjeev Jain, Bidyut Baran Saha

Research output: Contribution to journalArticlepeer-review

Abstract

To further the deployment of adsorption cooling systems for various applications, the cooling potential assessment of novel activated carbon-based pairs with R32 refrigerant is carried out in this work. The compositions of Maxsorb-III activated carbon with H25 Graphene nanoplatelets (GNP), 1-Hexyl-3-methylimidazolium bis(trifluormethylsulfonyl)imide ([HMIM][Tf2N]) ionic liquid, and polyvinyl alcohol (PVA), that have yielded the highest volumetric cooling energy (80:0:10:10) and thermal conductivity (40:40:10:10) respectively are considered for performance evaluation. The present study focuses on the under-explored aspect of heat exchanger optimization for HFC-based adsorbents through numerical analysis of two finned tube heat exchanger design configurations, viz., annular and longitudinal. A computationally less expensive numerical modeling is adopted, enabled by a scaling analysis. The impact of fin aspect ratios is analyzed for the composites with both the finned tube design configurations, and the significance of the adsorbent's thermal conductivity in realizing compact lightweight heat exchangers is highlighted. Further, an impact assessment of the adsorbent's orientation within the heat exchanger is presented for its anisotropic thermal conductivity characteristics. While it is observed that the annular fin configuration yields higher cooling performance for the composition 80:0:10:10, the longitudinal fin configuration yields a higher coefficient of performance for the composition 40:40:10:10 with a minimal decrement in the volumetric cooling power (<4.9%) over the annular fin configuration. The higher thermal conductivity of the composition 40:40:10:10 is seen to yield savings in the heat exchanger mass of up to 40.9% over that of the composition 80:0:10:10, for the same cooling capacity. The results indicate that present working pairs offer better cooling capacities and compact designs over other HFC-based studies in the literature.

Original languageEnglish
Article number106549
JournalInternational Communications in Heat and Mass Transfer
Volume140
DOIs
Publication statusPublished - Jan 2023

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Chemical Engineering(all)
  • Condensed Matter Physics

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