As a novel generation of thermal separators, the Wave rotor refrigerator (WRR) has replaced the traditional pressure-wave thermal separator. However, the isentropic refrigeration efficiency still needs to be improved compared with expander. A novel WRR system cycle was built and the system performance was thermal analyzed under various parameters, such as expansion efficiency or compression efficiency of wave rotor. The results are used to compare with the traditional WRR system. It is shown that the advantage provided by this novel cycle over the traditional WRR is an expansion process and a compression process is integrated into one unit, with a higher energy transfer efficiency and simple structure. The isentropic refrigeration efficiency of this novel cycle can be more than twice of the traditional WRR under the pressure ratio of 1.1. The experimental works are carrying out.
Three binary solutions composed of ionic liquid (IL), 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM] [DEP]), and selected refrigerants (water, ethanol or methanol) were proposed as new working pairs for absorption heat pumps or absorption refrigerators. The vapor–liquid equilibrium (VLE) data were measured by a static method at different temperatures and at different ILs mole factions and correlated by the None-Random Two Liquids (NRTL) activity coefficient models, and the average relative deviation were less than 3.3%. The solutions showed strong negative deviation from the Raoult's Law and were able to absorb vapor of water, ethanol or methanol. The excess enthalpies were measured and correlated at 298.15 K and atmospheric pressure. The results indicated that the mixing of [EMIM] [DEP] with water, ethanol or methanol were exothermal. The proposed solutions were proved to possess one of the fundamental features that a working pair must have in absorption cycle.
A study on the flow and separation performance of supersonic gas separator is carried out through numerical simulation and experimentation. The effect of area ratio on the separation performance under low pressure ratio has been researched. The simulation results indicate that with an increase of the area ratio AR, the intensity of the shockwave increases and the location approaches the throat; Shockwaves are absent in the diverging section of the nozzle when area ratio is 1.063 and the pressure ratio is within 1.25-1.75, which reaches the highest separation performance. The calculated and experimental results also show that the separation performance is the highest and can reach 40.82% when pressure ratio is 1.75. The calculated values are in agreement with the experimental results.
In present research ionic liquid, 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP]) and water were taken as the new working pair for absorption heat transformer (AHT). The thermodynamic cycle performance for this working pair was simulated based on its thermodynamic data, mass and energy balance for each component in a AHT. The effects of absorption and condensing temperature on the coefficient of performance (COP), exergy efficiency (ECOP), concentration deference between dense and dilution solutions and flow rate ratio were analyzed. The cycle performance comparison for AHT using two working pairs, H2O + [MMIM][DMP] and H2O + LiBr was carried out. The results indicate that the COP and ECOP of AHT for H2O+ [MMIM][DMP] are all lower than those for H2O + LiBr, but they can still reach 0.4 and 0.5 respectively when condensing and generation temperatures are 35 and 90 °C respectively. The excellent physical and chemical properties of ionic liquid mentioned above together with suitable cycle performance make this new working pair to have the potential application in absorption heat pump or absorption heat transformer.
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