Starch Particles, Energy Harvesting, and the “Goldilocks Effect”

• Published in: ACS omega Vol. 3; no. 4; pp. 3796 - 3803
• Main Authors: Hossain, Md. Amzad, Karoyo, Abdalla H, Dehabadi, Leila, Fathieh, Farhad, Simonson, Carey J, Wilson, Lee D
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 30.04.2018
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.8b00131

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 μm 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 μm, P w = 46 Å) and silica gel (SG13; SA = 478 m2/g, d p = 13 μm, 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.