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Water vapor adsorption isotherms at 20, 30, 50, 70 and 80 °C for: a PS-I; and b PS-II. Symbol represents the experiment whereas lines represent the GAB model  

Water vapor adsorption isotherms at 20, 30, 50, 70 and 80 °C for: a PS-I; and b PS-II. Symbol represents the experiment whereas lines represent the GAB model  

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Two polymer based sorbents PS-I and PS-II are analyzed for water sorption applications. Adsorption/desorption isotherms of water vapor onto PS-I and PS-II have been experimentally measured using a magnetic suspension adsorption measurement unit for adsorber temperature ranges 20-80 °C and evaporator temperature ranges 2-73 °C. The equilibrium adsor...

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... vapor adsorption isotherms at 20, 30, 50, 70 and 80 °C for PS-I and PS-II are shown in Fig. 5a, b, respec- tively. The equilibrium water vapor uptake corresponding to saturation condition at 30 °C by conventional silica-gel (RD type) is almost 0.40 kg/kg ( Sultan et al. 2014). However, at the same conditions, polymer sorbents PS-I and PS-II are enabling nearly 2 and 2.5 times higher ad- sorption amount as compared to silica-gel, ...
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... at the same conditions, polymer sorbents PS-I and PS-II are enabling nearly 2 and 2.5 times higher ad- sorption amount as compared to silica-gel, respectively. Figure 5 shows that the both samples enable relatively linear trend of adsorption isotherms at lower adsorption temperatures whereas sigmoid shaped isotherms are ob- tained on higher adsorption temperatures. The fact can be more visible if the adsorption data (on Fig. 5) is plotted against relative pressure. ...
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... 2 and 2.5 times higher ad- sorption amount as compared to silica-gel, respectively. Figure 5 shows that the both samples enable relatively linear trend of adsorption isotherms at lower adsorption temperatures whereas sigmoid shaped isotherms are ob- tained on higher adsorption temperatures. The fact can be more visible if the adsorption data (on Fig. 5) is plotted against relative pressure. This kind of phenomena is promising for designing an open-cycle and/or close-cycle adsorption heat pump ...
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... of the corresponding equations (see Table 2). However, the Freundlich model and its results are not incorporated in the article because of the max- imum fitting error (E = 2-18 %). The fitting results of each adsorption model for PS-I and PS-II are given in Table 3 which clarifies the distinction of GAB model over the others. It can be seen from Fig. 5a, b that the GAB model gives the good fit for all adsorption temperatures of PS-I and PS-II, respectively. For the relative pressure range of 0.10-0.90, the mean relative percentage deviation modulus (E) is found 2.95 and 3.14 % for PS-I and PS-II, respectively. The both polymer sorbents presents sigmoid shaped adsorption isotherms ...
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... especially for polar adsorbents-refrigerants, and even for the non-polar adsorbate (nitrogen) it comes at P/P o = 0.10 ( Brunauer et al. 1938). The GAB model could not represent these extraordinary forces responsible to formation of concave region and hence the adsorption uptake at P/P o \ 0.10 is underestimated by the model as shown in Fig. ...

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