raw · papers · ingested 2026-06-19
Ultralow-temperature-driven water-based sorption refrigeration enabled by low-cost zeolite-like porous aluminophosphate
Source: https://doi.org/10.1038/s41467-021-27883-4
Read from local Zotero full-text PDF (group 5183627 / Joule Heist).
Key findings
- Working material: EMM-8, an aluminophosphate (AlPO) with SFO topology and 12-membered-ring channels (~0.7 nm window, larger than the 8-ring openings ~0.4 nm of SAPO-34 / AlPO-LTA), giving weaker hydrophilicity and easier low-temperature water desorption. Built from cheap raw materials (pseudo-boehmite, phosphoric acid, 4-DMAPy SDA).
- Texture: BET surface area 879.63 m2/g, total pore volume 0.59 cm3/g (porosity 0.45, micropore volume 0.30 cm3/g), average micropore diameter ~0.7 nm; nitrogen-derived mesopore volume 0.29 cm3/g. Pellet packing density 0.93 g/mL, thermal conductivity 0.082-0.37 W/(m.K) at 25-100 C, dry specific heat 0.63-0.93 J/(g.K).
- Water-adsorption isotherm is S-shaped with a step in a narrow window P/P0 = 0.15-0.17; water-adsorption capacity 0.283 g/g at 25 C and P/P0 = 0.2, comparable to SAPO-34, AlPO-Tric, MOF-801, CAU-10, COF-TpPa, Co-CUK-1.
- Average isosteric enthalpy of water adsorption = 46.76 kJ/mol (Clausius-Clapeyron), only slightly above water’s evaporation enthalpy (44 kJ/mol), indicating low energy for desorption and thus high COP; attributed to a hydrogen-bonded water-cluster mechanism (vs strong electrostatic interaction in conventional zeolites).
- Cycling stability: no significant loss of water uptake over 30 adsorption/desorption cycles (adsorption 30 C / 30% RH, desorption 110 C under vacuum); hydrothermally stable in boiling water for 24 h and thermally stable up to 700 C.
- ADC performance: maximum cooling COP_C of 0.85 at an ultralow driving (desorption) temperature of 63 C (T_ev = 5 C, T_con = 30 C, T_des), exceeding state-of-the-art AlPO-LTA (0.75), MIP-200 (0.78), KMF-1 (0.75), Co-CUK-1 (0.83).
- Heat-pump performance: COP_H of 1.75 at driving temperature 82 C (T_ev = 15 C, T_con = 45 C), as high as best adsorbents Co-CUK-1 (1.77) and KMF-1 (1.74); required driving temperatures are 5-15 C lower than reference materials. Scaled-up to ~100 g batches in a 2 L reactor.