Study on operation performance and application potential of the piston-type thermally-driven pump

Abstract

To eliminate the high-quality energy consumption of the existing thermally-driven pump and then make it replace the mechanical pump, the piston-type thermally-driven pump with a similar structure to the linear compressor was proposed and studied in the paper. The coupling mechanism of working fluid flow and element dimension was analysed based on the force analysis of the piston assembly. In experimental data analysis, the variation of working fluid condition is used to determine the pump operation stroke. The experimental result shows variation tendencies of the vapor-phase fluid pressure and flow rate are greatly affected by its compressibility. The throttle valve has a major effect on the liquid-phase fluid pressure and flow rate besides the vapor-phase fluid flow rate. And the pump operation period decreases by 0.05 s ∼ 0.1 s as the vapor-phase fluid pressure and the throttle valve opening change under the testing condition. Meanwhile, the correlation mechanism of the action force, displacement and velocity of the piston assembly was analysed through a theoretical simulation. It can be discovered that the piston assembly velocity increases by 7.1 %∼12.6 % and the pump operation cycle decreases by 1.9 %∼6.8 % with increasing vapor-phase fluid pressure. In addition, the improvement direction of the pump structure was proposed based on a comparison between the experimental research and the theoretical analysis. Compared with the mechanical pump, the simulating result shows the thermally-driven pump can in theory reduce the relative power consumption by about 82 %. Finally, an alternative strategy was presented for substituting the mechanical pump with the piston-type thermally-driven pump in the absorption and ejector refrigeration systems, to verify its application potential in the industrial field.