Studies on High Efficiency Absorption System Using Ethylamine + Water + Lithium Bromide

研究乙胺+水+溴化锂体系（水：溴化锂= 2:1质量）是否适用于吸收式制冷机和热泵。测定了溴化锂+乙胺水溶液的物理性能（密度、粘度、表面张力、蒸汽压和汽液平衡）和热性能（热容量和混合积分焓）。在不同温度和乙胺浓度下测量了密度、粘度、表面张力、蒸汽压、汽液平衡和热容量。得到了乙胺浓度在10-70wt%范围内的溶液在278.15K时的混合积分焓。根据实验数据，得到了蒸汽压、热容和混合积分焓的经验公式。进行了性能系数的理论计算，考察了该系统的性能特性。利用不同温度、压力和乙胺浓度下的焓值计算吸收式制冷机和吸收式热泵的性能系数。将该体系的性能与乙胺+水体系进行了比较。该系统适用于风冷式单级吸收式制冷机和单级吸收式热变压器。

This investigation was undertaken to examine whether the ethylamine + water + lithium bromide system (water : lithium bromide=2 : 1 mass) is suited for absorption refrigerating machine and heat pump. The physical properties (density, viscosity, surface tension, vapor pressure and vapor-liquid equilibrium) and the thermal properties (heat capacity and integral enthalpy of mixing) of lithium bromide + ethylamine aqueous solutions were measured. Measurements of density, viscosity, surface tension, vapor pressure, vapor-liquid equilibrium and heat capacity were carried out at various temperatures and ethylamine concentrations. The integral enthalpies of mixing at 278.15K were obtained for solutions whose ethylamine concentrations ranged from 10-70wt%. The empirical formulae for vapor pressure, heat capacity and integral enthalpy of mixing were obtained from experimental data.Theoretical calculations of the coefficients of performance were undertaken to examine the performance characteristics of this system. The coefficients of performance for absorption refrigerating machines and absorption heat pump were calculated using the enthalpies at various temperatures, pressures and ethylamine concentrations. The performance characteristics of this system were compared with that of the ethylamine + water system. This system was found to be suitable for an air-cooled single-stage absorption refrigerating machine and a single-stage absorption heat transformer.