| An integral part of the liquid desiccant air conditioning system is solution regeneration, and the performance of dehumidifier is directly affected by the regenerator. The essence of different regenerate methods is to improve the efficiency and reduce the energy cost. Vacuum technology is applied in regenerate process in this paper, intended to discuss the performance of the regenerator with this new regeneration method in vacuum conditions.This paper includes five chapters that can be reduced to three sections. The first section is about the research progress in related areas of solution regeneration and the theoretical analysis of boiling process, also the mathematical model of the regenerate process is build based on the principle of mass and energy conservation. In the second section, the test apparatus and experimental data are mainly discussed. Use the lithium chloride water solution as the liquid desiccant, the impact of the test conditions is including the temperature of heat source(64℃~76℃), initial temperature of solution(45℃~60℃), concentration of solution(28%~34%), pressure of regenerate process(4k Pa~10k Pa) and temperature of cold water(12℃~24℃). The distillation rate and thermal efficiency of the system are investigated, in this way to get the impact trends. Last the boiling characteristics are discussed such as the heat transfer coefficient. Optimization of the regeneration system is conducted in section three. In the last section, comparison between simulation and experimental results, energy-balance relationship of the apparatus and fitting correlations of the parameters are presented. And the optimal operating parameters are obtained.According to the above theoretical analysis and experimental research, the main conclusions are as follows:(1) The novel method of solution regeneration under vacuum conditions has high coefficient, combined with dehumidifier may built a liquid desiccant air conditioning system with compact structure, energy storage, environmental protection and has no effects by the outdoor air conditions, which has a great potential.(2) The distillation rate is increasing with the temperature of heat source in a certain range, and to improving the initial temperature of solution is also conducive to the regeneration. When the other parameters are constant, the higher of initial temperature, the more thermal energy can release in the process to promote the regeneration. The distillation rate is increasing with the decrease of concentration and pressure. Whereas the phenomenon of droplet entrainment should be noticed when the concentration is low and the security and stability of the system should be taken into account when the pressure is low.(3) Under the test conditions, the concentration has the maximum significance on the regeneration performance while the temperature of cold water minimum. Boiling heat source temperature increases with the raise of heat flux under certain pressure, but with the change of pressure is more complex.(4) When the concentration of desiccant is 30%, the optimum testing model for regeneration is temperature of heat source 70℃, initial temperature of solution 60℃, pressure 4k Pa and temperature of cold water 20℃. While the heating is 7.56 k W, the regeneration rate is 19.17 g/(m2·s) and the thermal efficiency is 84.2% in the optimal conditions. Also 87.1% of the efficiency of the catcher is obtained. |
