Sorption Study of a Starch Biopolymer as an Alternative Desiccant for Energy Wheels

Abstract

The sorption of water vapor on high amylose starch was investigated as an alternative desiccant for air-to-air energy exchangers used in ventilation units. Sorption performance of micron-sized mesoporous high amylose starch (HAS15, d p = 15 μm, P w = 46 Å) and two mesoporous silica gel samples (SG13, d p = 13 μm, P w = 62 Å; P w = 62 Å; SG55, d p = 55 μm, P w = 77 Å) were studied and compared. Transient water vapor sorption tests were performed using small-scale energy exchangers coated with HAS15 and silica gel. Although N2 gas adsorption tests showed lower sorption capacity for HAS15 compared to the silica gel samples, higher sorption rates and uptake capacity were shown for HAS15 when measured by water vapor transient sorption results. In addition, the latent effectiveness, an indicator of moisture recovery efficiency for exchangers, was calculated for each exchanger. With the same amount of desiccant coated on the energy exchanger channels, the latent effectiveness of the HAS-coated material was 2%–13% greater than that of the silica gel materials, depending on the operating conditions.

Vapor Adsorption Transient Test Facility for Dehumidification and Desorption Studies

“…Our group has demonstrated a significant improvement in the latent effectiveness of the exchanger according to the nature of the desiccant coating, as shown by the significant differences between silica gel particles with variable textural properties and high-amylose starch biopolymers (Fathieh et al, 2015;Fathieh et al, 2016;Dehabadi et al, 2017;Hossain et al, 2018). The higher rate of sorption and the increased uptake capacity of high-amylose starch (HAS) per unit mass have been shown to exceed those of silica gel materials.…”

“…Then, the NTUm can be determined based on the effectiveness-NTUm relation of a PF heat exchanger using Equation 6 (Fathieh et al, 2016)…”

“…Third, a large degree of uncertainty results from multiple dehumidification and regeneration cycles, which leads to the narrowing of the valid test range of the experiment. Fathieh et al (2016) showed that the propagated uncertainty would be very high (ca. 30%) for selected operating conditions when seeking to predict the effectiveness of a CF energy wheel based on the small-scale PF test section.…”

“…By contrast, the small-scale transient test device circumvents these requirements. In particular, the transient dehumidification and regeneration measured using the small-scale test facility revealed that the latent effectiveness of large-scale energy wheels was accurately predicted with comparable geometry and coating (Fathieh et al, 2016). The latent effectiveness of the systems varied depending on the angular speeds, air flow rates, and the level/type of coating on the metal substrate of the exchanger.…”

Recyclable, shape‐memory, and self‐healing soy oil‐based polyurethane crosslinked by a thermoreversible Diels–Alder reaction

“…With an increase of worldwide environmental pollution caused by nonbiodegradable polymers and the impact of growing petroleum crisis, the research and development of biodegradable materials from renewable resources, including cellulose, starch, lignin, chitin, chitosan, vegetable oil, and protein have attracted much attention. Among those natural products, soy oil might be the most suitable one to be used in synthesizing polymers, especially polyurethane, because of its good solubility, excellent miscibility, low cost, high output, and easy to modify.…”