Biosorptive efficacy of granular activated carbon in pressure swing adsorption based model cooling system:...

The notable environmental concerns of the halogen-containing obnoxious conventional refrigerants have grounded to devise the environmentally benign and efficient cooling system. In view of this alarming issue, an experimental model cooling system based on pressure swing adsorption-desorption (PSAD) mechanism has been contrived for its performance assessment and analysis of isotherm modeling. The physicochemical properties of the wood apple (Limonia acidissima) shell-derived carbonized char are enhanced by multi-stage activation to obtain two activated carbon granular adsorbents viz. PCACG and ACG towards their application in the proposed system. The performance indicative microporous characteristics of the adsorbents are investigated, and it is observed that the indigenously prepared activated carbon possesses high surface area, i.e., 1065 m² gm^-1 and 1023 m² gm ^-1 for PCACG and ACG, respectively. Carbon dioxide and bio-precursor-based adsorbents are used as adsorbent-adsorbate pair in the developed single-bed cooling system. The coefficient of performance (COP) of the cooling system are computed to be 4.93 and 2.79 utilizing PCACG and ACG, respectively while the cooling effects are quantified as 146.26 J s ^-1 and 128.48 J s^-1.Besides, the CO₂ gas adsorption mechanism onto solid adsorbent surfaces has been interpreted by Langmuir, Dubinin-Raduskevich (D-R), and Dubinin-Astakhov (D-A) isotherm models. Among them, D-A isotherm has accurately predicted the adsorption mechanism of carbon dioxide on to adsorbent. Importantly, the cost estimation of preparing PCACG and ACG exhibited the cost-effectiveness for their successful application. Based on their comparative characteristics, it is observed that the PCACG adsorbent is more energy efficient than ACG in the long run.