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raw · papers · ingested 2026-06-19

A review on solar-powered cooling and air-conditioning systems for building applications

Source: https://doi.org/10.1016/j.egyr.2022.01.172

Read from local Zotero full-text PDF (group 5183627 / Joule Heist).

Key findings

  • Solar adsorption (SADS) basics: closed 4-phase cycle (heating/pressurization, desorption/condensation, cooling/depressurization, adsorption/evaporation) analogous to vapor compression; intermittent cooling requires 2+ adsorbers operating out of phase. Common adsorbents: activated carbon, silica gel, zeolite; refrigerants: water, methanol/ethanol, ammonia. SADS is more complex, heavier, more expensive and lower-COP than absorption (SABS).
  • Anyanwu & Ogueke max-possible cooling COP by pair: activated carbon/methanol 0.16, activated carbon/ammonia 0.19, zeolite/water 0.30; zeolite/water best for AC, activated carbon/ammonia best for deep freezing/ice making.
  • SADS performance table (pair | collector | capacity | COP): silica gel/water (ETSC) 220 kW/kg silica gel, COP 0.63 (best at 85 C driving); activated carbon/ethanol (PTSC) 500 W, COP 0.68; silica gel/water (PTSC) 11 kW, COP 0.5 (0.4-0.55 in daytime); activated carbon/methanol (ETSC) 35 kW, COP 0.403; zeolite SAPO-34/water (ETSC) 10 kW, COP 0.575 (best at 75 C, EER 5.8); activated carbon/ammonia 25-80 W/kg, COP 0.12-0.24.
  • Mass/heat recovery gains: heat recovery cycle raised SADS COP ~25% (Wang et al.); Tso et al. zeolite 13X/CaCl2/water heat+mass recovery improved COP ~125%, and mass recovery + pre-heating/pre-cooling gave 100% COP increase vs basic cycle. Khan three-bed silica gel-water mass recovery best at 65-75 C driving (range 55-80 C, 30 C coolant, 14 C chilled water).
  • Cascading double-effect adsorption (Marlinda Uyun): condenser heat of top cycle drives bottom cycle; double-effect COP exceeded single-effect at 100-150 C driving, COP doubled when driving reached 130 C.
  • Absorption (SABS) benchmark for comparison: single-effect FPSC ~85 C COP 0.7; double-effect FPSC/PTSC ~130 C COP 1.2; triple-effect ETSC/concentrating ~220 C COP 1.7. H2O/LiBr (high COP, low pressure, non-toxic, crystallization risk) vs NH3/H2O (sub-zero evaporation but toxic, needs rectifier, high pressure).
  • Solid desiccant (SDS, rotating silica-gel/LiCl wheel): SCOP ~2 (Spain), COP up to 0.728 (Iran), moisture removal up to ~14 kg/h; one hybrid SDS-IEC saved 46.8% vs direct-expansion, SCOP ~2.8.
  • Collector area per kW cooling (Henning): absorption 2.77 m2/kW, adsorption 3.49 m2/kW, rotor desiccant 1.73, liquid desiccant 1.26 (adsorption needs the largest collector area among closed cycles). Absorption is the most commercially installed (~59% of installed SCACSs, mainly Germany). SABS minimum driving temp ~80 C (FPSC).