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Adsorption cooling and desalination (ACD) system powered by renewable energy has been considered as a promising solution to solve interconnected global problems such as freshwater scarcity, high-cost air conditioning, CO2 emission, and global warming. In this work, a new nanoporous silica was synthesized through a self-assembly process using a combination of ionic and non-ionic surfactants. The silica has shown unique pore structures, including high surface area and large pore volume, as well as ideal pore size distribution. The new silica was deposited (coated) over the ligaments of aluminum foam for use as a sorption bed. An uncoated aluminum foam packed with conventional silica RD (regular density) particles serves as a baseline sorption bed. The freshwater production rate and cooling power produced using the two sorbents were compared. Silica RD outperforms the new silica for cooling while the new silica is far better for desalination application. Insights for such results are provided.

Eighteen polycyclic aromatic hydrocarbons (PAHs), 24 n-alkanes, 7 hopanes, 2 cholestanes, inorganic ions, elements and carbon fractions were analyzed in real-world source samples of PM

Eighteen polycyclic aromatic hydrocarbons (PAHs), 24 n-alkanes, 7 hopanes, 2 cholestanes, inorganic ions, elements and carbon fractions were analyzed in real-world source samples of PM2.5 (fine particulate matter) from traffic emissions (gasoline vehicles-TGV, diesel vehicles-TDV, diesel ship-TDS, and heavy oil ships-THOS), coal combustion (coal-fired industrial boilers-CIB, power plants-CPP, and residential stoves-CRS), industrial process emissions (cement industry-IPCI, and steel industry-IPSI), and dust (soil dust-DSD, road dust-DRD, and construction dust-DCD). High molecular weight (sum of five to seven rings) PAHs accounted for higher fractions for TGV (80%) and THS (61%) than for TDV, TDS and coal combustion sources (31%–47%). Hopane ratios (C29αβ/C30αβ) in coal related sources were mostly higher than 1, whereas that of traffic emissions was lower than 1. The homohopane index [S/(S + R)], which is a useful index for identifying the maturity of fuels, ranked as TGV > THS > TDV and TDS > coal combustion. For n-alkane profiles, coal related sources showed peaks at C16–C19, TDV, TDS and THS showed similar peaks at C17–C25, but peaks for DSD (C30–C32), DRD (C17–C20, C24–25 and C30–C31), CRS (C16–C18 and C28–C29) and TGV (C24–C26) are different. Organic markers were selected which can best differentiate the subtypes within source categories by considering the component levels and variations. Through a comprehensive review, we showed that it is inadvisable to directly use diagnostic ratios for source attribution, although their trends can assist in identifying influential sources.

Performance of two types of desiccant silica gel aluminum foam heat exchangers - desiccant coated heat exchanger (DCHE) and desiccant packed heat exchanger (DPHE) are evaluated experimentally and numerically. The DCHE is fabricated by coating silica gel over the ligaments of an aluminum foam, while the DPHE is built by packing an aluminum foam with silica particles. Equilibrium isotherms of the two heat exchangers are measured using the gravimetric approach. An open flow loop test rig is designed and built to measure the dry bulb temperature and humidity ratio of air upstream and downstream of the desiccant heat exchangers during the humidification and dehumidification process. In addition, a mathematical model is developed to investigate the heat and mass transfer process in the two desiccant heat exchangers. The experimental data obtained are used to validate the numerical results, and good agreement is established. The effects of heat exchanger length and inlet operating conditions on the performance of DPHE and DCHE are investigated. Experimental and numerical results indicate that the DPHE outperforms the DCHE in terms of cooling capacity and moisture removal capacity. It is observed that the performance of the DPHE is close to that of the DCHE in handling sensible heat loads but exceeds the latter in removing latent heat loads. The DPHE can provide dehumidified air for a longer time due to its higher moisture removal ability and higher density of the desiccant material compared to the DCHE.

Commonly used thermal analysis tools such as calorimeter and thermal conductivity meter are separated instruments and limited by low throughput, where only one sample is examined each time. This work reports an infrared based optical calorimetry with its theoretical foundation, which is able to provide an integrated solution to characterize thermal properties of materials with high throughput. By taking time domain temperature information of spatially distributed samples, this method allows a single device (infrared camera) to determine the thermal properties of both phase change systems (melting temperature and latent heat of fusion) and non-phase change systems (thermal conductivity and heat capacity). This method further allows these thermal properties of multiple samples to be determined rapidly, remotely, and simultaneously. In this proof-of-concept experiment, the thermal properties of a panel of 16 samples including melting temperatures, latent heats of fusion, heat capacities, and thermal conductivities have been determined in 2 min with high accuracy. Given the high thermal, spatial, and temporal resolutions of the advanced infrared camera, this method has the potential to revolutionize the thermal characterization of materials by providing an integrated solution with high throughput, high sensitivity, and short analysis time.