A Simple Design Approach of Two-Phase Ejectors for CO2 Transcritical Heat Pumps

Integrating a two-phase ejector in mechanical vapor compression heat pumps is practical and low-cost solution for improving performance reducing energy consumption. Typically, using an to recover part of the important pressure expansion losses CO2 systems may improve operating conditions compressor. One prerequisites success such application proper design ejector. This study mainly dedicated developing simple approach design. The advantage as expander transcritical pump first introduced. Compressor operation particularly improved. development model expanding from presented. Validation thermodynamic with experimental results literature shows predictions be within acceptable range discrepancy. primary nozzle throat diameter calculations do not exceed ±8% error conditions. predicted at outlet limit -15% +3%. A example estimating ejectors geometry integrated show decrease diameters drop Tevap, especially throat. Dmix also occurs Tevap optimal obtained each condition considered. diffuser based on compromise between velocity length diffuser. detailed procedure proposed model, complemented data literature, valuable tool rapidly generating useful obtaining preliminary designs