To evaluate the thermal-hydraulic characteristics and mechanism of the bubble absorption process inside a solution in a vacuum environment, we design an experimental device for measuring the bubble absorption and transport characteristics of solutions in a pressurized vertical tube and introduce the structure and work of the device. Its reliability is verified by system vacuum pressure experiments, and its accuracy is verified by bubble flow and energy conservation experiments. The results show that pressurization technology achieves bubble absorption in a vacuum environment. The vacuum increase rate of the system is only 2.33% after 12 h of idling, corresponding to a gas leakage rate of 2.4 mL/h. The device exhibited good reliability. The behavior of bubble generation, rising, collision, coalescence, and rupture during the experiment was consistent with the bubble flow behavior reported in the literature. The maximum relative deviations in the outlet temperature and outlet concentration of the solution and cooling water were 0.08%, 0.02%, and 0.01%, respectively. The maximum errors of the energy calibration experiment of the different solution inlet temperatures and solution flow rates are 10.4 J and 12.5 J, respectively, and thereby the device has good accuracy. The experimental device provides a good experimental foundation for evaluating the transport characteristics of bubble absorption and the heat transfer characteristics of bubble absorption in a vacuum environment and revealing its transfer mechanism.

Solution absorption energy storage is a new energy storage and release technology characterized by high energy storage density, low heat loss, good mobility, and long-term energy storage. Energy storage density and energy storage efficiency are the key indexes for measuring the energy storage capacity of absorption energy storage systems and the key parameters for evaluating the energy conversion efficiency of absorption energy storage systems, respectively. Based on thermodynamic principles, the energy storage characteristics and applicability of absorption energy storage systems were investigated using six types of absorption solutions under different conditions. The results show that both energy storage density and energy storage efficiency increase with an increase in heat source temperature and cooling water temperature and decrease with solution concentration. At a heat source temperature of 70-120 ℃ and condensing temperature of 24-36 ℃, NaOH-H₂O has the largest energy storage density and efficiency, CaCl₂-H₂O has the smallest energy storage density and efficiency, and LiBr-H₂O has the widest applicability of temperature range.