Starch Particles, Energy Harvesting, and the "Goldilocks Effect".

ABSTRACT: This study reports on the unique water vapor adsorption properties of biomass-derived starch particles (SPs). SPs offer an alternative desiccant for air-to-air energy exchangers in heating, ventilation, and air conditioning systems because of their remarkable adsorption-desorption performance. SP₁₅ has a particle diameter (d _p) of 15 ?m with a surface area (SA) of 2.89 m²/g and a pore width (P _w) of 80 Å. Microporous starch particles (SP₁₅) were compared with high amylose starch (HAS₁₅; SA = 0.56 m²/g, d _p = 15 ?m, P _w = 46 Å) and silica gel (SG₁₃; SA = 478 m²/g, d _p = 13 ?m, P _w = 62 Å). Transient water vapor tests were performed using a customized small-scale energy exchanger coated with SP₁₅, HAS₁₅, and SG₁₃. The water swelling (%) for SP₁₅ was ca. 2 orders of magnitude greater with markedly higher (ca. three- and six-fold) water vapor uptake compared to HAS₁₅ and SG₁₃, respectively. At similar desiccant coating levels on the energy exchanger, the latent effectiveness of the SP₁₅ system was much improved (4-31%) over the HAS₁₅ and SG₁₃ systems at controlled operating conditions. SP₁₅ is a unique desiccant material with high affinity for water vapor and superior adsorption properties where ca. 98% regeneration was achieved under mild conditions. Therefore, SPs display unique adsorption-desorption properties, herein referred to as the "Goldilocks effect". This contribution reports on the utility of SPs as promising desiccant coatings in air-to-air energy exchangers for ventilation systems or as advanced materials for potential water/energy harvesting applications.

SUBMITTER: Hossain MA 

PROVIDER: S-EPMC6641621 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature