raw · papers · ingested 2026-06-19
A Review on Solar Adsorption Chiller using Silica gel water Mixtures
Source: https://doi.org/10.2139/ssrn.3498098
Read from local Zotero full-text PDF (group 5183627 / Joule Heist).
Key findings
- Working pair: silica gel-water chosen because silica gel regenerates at lower temperature than zeolite/activated carbon and water has high latent heat. Stated system envelope: generation/regeneration temperature ~70-80 C, chilled water ~10-20 C, condenser/evaporator pressure range 1-12 kPa, chiller COP 0.3-0.5 (paper later states optimum 0.1-0.3 for solar-driven cases).
- Cho et al. system: two adsorbers (110 kg silica gel, 2-3 mm dia, aluminum circular-fin tube HX, 46.9 m2), condenser 2.5 m2, evaporator 8.15 m2; hot water 85 C at 0.833 kg/s, cooling water 14 C at 1.111 kg/s, chilled water 8.4 C at 0.278 kg/s. Cold capacity 1.2 RT, chilled water 4-7 C, total cycle time ~350 s.
- Saha et al. cycle simulation (Tdes 50 C, Tads 30 C, 300 s cycle): cooling capacity 1.5-1.7 kW, COP 0.2-0.3, efficiency 0.25-0.45; performance strongly limited by thermal capacitance and adsorber/desorber conductance.
- Wang et al. four-bed vs two-bed: four-bed chiller delivers ~12% higher ultimate SCP at same HX inventory; two-bed COP enhanced 14% (long cycle) / 38% (short cycle), four-bed COP enhanced 25%. Operating points: cooling water 29.4 C, chilled water 12.2 C, hot water 85 C.
- Chang et al. solar compound system (Taiwan golf course, plate-fin tube HX): standard conditions 80 C hot / 30 C cold / 14 C chilled gave COP 0.37 and 9 kW cooling; SCP 72 W/kg; field test COP 0.403, SCP 7.79 kW. Solar-heating efficiency 28.4%, adsorption cooling 45.2%, solar cooling 12.8%.
- Rezk & Al-Dadah 450 kW empirical lumped model: raising generation temperature lift 40->65 K increased cooling capacity ~180->342 kW with small COP drop (0.63->0.60) and efficiency drop (0.68->0.52); GA-optimized cycle (ads/des 345 s, mass recovery 12 s, heat recovery 14 s) raised cooling capacity by 8.3%.
- El-Sharkawy et al. CPC solar two-bed Si-H2O (900 s cycle, 45 s switching): cycle/solar COP peaked at 0.50/0.30; cooling capacity ~14.8 kW (Cairo/Jeddah), 15.8 kW (Aswan); adding hot-water buffer storage raised daily average cooling capacity by up to 12% and average COP by up to 9%.
- General design levers identified: lower cooling-water temperature, higher chilled-water inlet temperature, mass-recovery (~60-180 s) and heat-recovery (hot water 65-85 C) steps, multi-bed operation, and buffer storage all improve COP/SCP.