为开发出一种适用于吸附制冷的高性能吸附剂,选择了3种不同孔径的商用硅胶,孔径分别是2～3、4～7、8～10 nm,利用浸泡的方法将氯化钙嵌入硅胶微孔内来制备复合吸附剂,并对吸附剂的吸附性能进行了实验测试.测试结果表明:对于2～3 nm的硅胶,由于孔径较小,氯化钙的浸入堵塞或者部分堵塞了水进入硅胶的传质通道,导致复合吸附剂不论是吸附量还是吸附速率与纯硅胶相比都没有提高；而对于4 ～7 nm和8～ 10 nm的硅胶,其复合吸附剂不论是吸附量还是吸附速率都较其相应的纯硅胶有大幅提高.复合吸附剂在20％湿度下吸附20 min和2h的吸附量分别是8.08 g/100 g和15.7 g/100 g,在同等工况下,纯硅胶的吸附量分别是1.96 g/100 g和2.0 g/100 g.用制备的复合吸附剂制作了一台小型吸附制冷机并进行了测试,当热源温度为90℃,冷却水温度为35℃时,在整个循环周期内(15 min),制冷功率为1.03 kW,单位质量吸附剂的制冷功率(SCP)为128.3 W/kg,性能系数(COP)为0.27.%To develop a high performance adsorbent for adsorption refrigeration, three kinds of commercial silica gel with pore sizes of 2 -3 nrn, 4-7 nra, and 8 ~10 nm, respectively, were used for preparing composite adsorbents by soaking them into the solution of calcium chloride. After that, the performances of composite adsorbents were tested by the experimental method. The testing results indicate that both the adsorption amount and adsorption rate of composite adsorbents for the 4 ~7nm and 8 ~ l0nm silica gel improve greatly compared to pure silica gel, but does not improve for the 2 ~ 3 nm silica gel due to the much smaller pore size which may block the inner channel when the pore is filled by CaCl2. The water uptake of the composite adsorbent is 8. 08 g/100 g and 15, 7 g/100 g, respectively, at a relative humidity of 20% and adsorption time of 20 min and 2 hours, but the water uptake of pure silica gel is 1.96 g/100 g and 2.0 g/100 g, respectively, under the same conditions. Furthermore, an adsorption chiller was produced by using composite adsorbents. The performance testing of the adsorption chiller shows that the cooling capacity, SCP, and COP are 1. 03 kW, 128- 3 W/kg, and 0. 27, respectively, when the hot water temperature, cooling water temperature, and circulation time are 90℃ , 35℃ , and 15 min, respectively.
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