Research on Adsorption and Energy Storage of Refrigerants R1234yf and R32 in MOF-74
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摘要: 利用流体分子在纳米多孔材料固体表面吸附分离过程中热能与表面能的相互转化，可以提高循环工质吸热量。采用分子模拟（分子动力学和巨正则蒙特卡洛）方法并结合吸附理论开展了R1234yf和R32在MOF-74中的吸附储能研究。在纯工质吸附中，发现R32在MOF中的吸附量高于R1234yf的吸附量。制冷工质在Zn-MOF-74中的吸附量比在Co-MOF-74中的吸附量大，且R1234yf达到饱和吸附所需的压力低于R32在相应吸附剂内达到饱和所需压力值。而在混合工质吸附中，R1234yf的吸附量高于R32的吸附量，随着温度的增加，R1234yf的吸附量呈现逐步上升的趋势，而R32则逐渐减少。经储能计算表明，M-MOF-74（M=Co, Zn）颗粒质量分数越高，混合工质相变所需吸收热能越多。Abstract: The heat absorption of circulating working medium can be improved by using the mutual transformation of thermal energy and surface energy in the process of adsorption and separation of fluid molecules on the solid surface of nano-porous materials. In this paper, molecular simulation (molecular dynamics and Grand Canonical Monte Carlo) and adsorption theory are used to study the adsorption and energy storage of R1234yf and R32 in MOF-74. In the adsorption of pure working medium, it is found that the adsorption capacity of R32 in MOF is higher than that of R1234yf. The adsorption capacity of refrigerant in Zn-MOF-74 is larger than that in Co-MOF-74, and the pressure required for R1234yf to reach saturation adsorption is lower than that required for R32 to reach saturation in the corresponding adsorbent. In the mixed working medium adsorption, the adsorption capacity of R1234yf is higher than that of R32. With the increase of temperature, the adsorption capacity of R1234yf shows a gradually increasing trend, while that of R32 gradually decreases. The energy storage calculation shows that the higher the mass fraction of M-MOF-74 (M = Co, Zn) particles, the more heat energy needed to be absorbed for the phase transition of the mixed working medium.
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Key words:
- R1234yf /
- R32 /
- MOF-74 /
- Adsorption /
- Energy storage /
- Molecular simulation
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图 5 R1234yf与R32混合工质在M-MOF-74中的吸附
Figure 5. Adsorption of Mixed Working Medium of R1234yf and R32 in M-MOF-74
图 6 3.5 MPa和5 MPa时含不同M-MOF-74质量分数的混合工质的储能百分比与温度差关系
Figure 6. Relationship between Energy Storage Percentage and Temperature Difference of Mixed Working Medium with Different Mass Fractions of M-MOF-74 at 3.5 MPa and 5 MPa
表 1 MD方法模拟的MOF-74内能值
Table 1. Internal Energy of MOF-74 Simulated by MD
温度/K 内能值（M=Co）/（kJ·kg−1) 内能值（M=Zn）/（kJ·kg−1) 293 −375152 −473556 313 −375103 −473477 333 −375055 −473399 353 −375006 −473321 373 −374957 −473242 393 −374908 −473164 
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