This paper is focused on the cascade refrigeration cycle using natural refrigerant CO 2-NH 3. The properties of refrigerants CO 2 and NH 3 are introduced and analyzed.CO 2 has the advantage in low stage of cascade ref...This paper is focused on the cascade refrigeration cycle using natural refrigerant CO 2-NH 3. The properties of refrigerants CO 2 and NH 3 are introduced and analyzed.CO 2 has the advantage in low stage of cascade refrigeration cycle due to its good characteristics and properties. The thermodynamic analysis results of the CO 2-NH 3 cascade refrigeration cycle demonstrates that the cycle has an optimum condensation temperature of low stage and also has an optimum flow rate ratio.By comparing with the R13-R22 and NH 3-NH 3 cascade refrigeration cycles, the mass flow rate ratio of CO 2-NH 3 is larger than those of R13-R22 and NH 3-NH 3, the theoretical COP of CO 2-NH 3 cascade refrigeration cycle is larger than that of the R13-R22 cascade cycle and smaller than that of the NH 3-NH 3 cascade cycle. But the real COP of CO 2-NH 3 cascade cycle will be higher than those of R13-R22 and NH 3-NH 3 because the specific volume of CO 2 at low temperature does not change much and its dynamic viscosity is also small.展开更多
Chengdu Branch,Chinese Science Academy,Chengdu610041)abstract:[Mn(ECZ)abstract: 3 ](NO 3 )abstract: 2 is newly prepared by the aqueous solutions of Mn(NO 3 )abstract: 2 and ethyl carbazate(ECZ)abstract:.The crystal st...Chengdu Branch,Chinese Science Academy,Chengdu610041)abstract:[Mn(ECZ)abstract: 3 ](NO 3 )abstract: 2 is newly prepared by the aqueous solutions of Mn(NO 3 )abstract: 2 and ethyl carbazate(ECZ)abstract:.The crystal structure has been determined by X-ray crystal diffraction analysis.It belongs to monoclinic with space group of P2 1 /n.The crystal parameters are:a=1.3974(2)abstract:nm,b=0.8796(2)abstract:nm,c=3.4322(7)abstract:nm,β=9 1.25(1)abstract:°,V=4.2175(1)abstract:nm 3 ,Z=8.Its molecular weight is491.30.Mn 2+ is located on the center of the molecular structure.Ethyl carbazate serves a s a bidentate ligand which coordinates to the metal cations with its carbonyl ox ygen atom and the terminal hydrazine nitrogen atom,forming five-member chelatin g rings,and three such rings are formed in each molecule.The coordination number of the metal ion is six and the coordination configuration of the cen-tral ion is octahedral.Specially,antimer configuration phenomenon is found in the molecu le.The complex is fur-ther characterized by element analysis and IR measurement s.The thermal decomposition mechanism is studied by using TG-DTG and DSC techni ques.CCDC:215675.展开更多
文摘This paper is focused on the cascade refrigeration cycle using natural refrigerant CO 2-NH 3. The properties of refrigerants CO 2 and NH 3 are introduced and analyzed.CO 2 has the advantage in low stage of cascade refrigeration cycle due to its good characteristics and properties. The thermodynamic analysis results of the CO 2-NH 3 cascade refrigeration cycle demonstrates that the cycle has an optimum condensation temperature of low stage and also has an optimum flow rate ratio.By comparing with the R13-R22 and NH 3-NH 3 cascade refrigeration cycles, the mass flow rate ratio of CO 2-NH 3 is larger than those of R13-R22 and NH 3-NH 3, the theoretical COP of CO 2-NH 3 cascade refrigeration cycle is larger than that of the R13-R22 cascade cycle and smaller than that of the NH 3-NH 3 cascade cycle. But the real COP of CO 2-NH 3 cascade cycle will be higher than those of R13-R22 and NH 3-NH 3 because the specific volume of CO 2 at low temperature does not change much and its dynamic viscosity is also small.
文摘Chengdu Branch,Chinese Science Academy,Chengdu610041)abstract:[Mn(ECZ)abstract: 3 ](NO 3 )abstract: 2 is newly prepared by the aqueous solutions of Mn(NO 3 )abstract: 2 and ethyl carbazate(ECZ)abstract:.The crystal structure has been determined by X-ray crystal diffraction analysis.It belongs to monoclinic with space group of P2 1 /n.The crystal parameters are:a=1.3974(2)abstract:nm,b=0.8796(2)abstract:nm,c=3.4322(7)abstract:nm,β=9 1.25(1)abstract:°,V=4.2175(1)abstract:nm 3 ,Z=8.Its molecular weight is491.30.Mn 2+ is located on the center of the molecular structure.Ethyl carbazate serves a s a bidentate ligand which coordinates to the metal cations with its carbonyl ox ygen atom and the terminal hydrazine nitrogen atom,forming five-member chelatin g rings,and three such rings are formed in each molecule.The coordination number of the metal ion is six and the coordination configuration of the cen-tral ion is octahedral.Specially,antimer configuration phenomenon is found in the molecu le.The complex is fur-ther characterized by element analysis and IR measurement s.The thermal decomposition mechanism is studied by using TG-DTG and DSC techni ques.CCDC:215675.
