An experimental investigation of performance and instabilities of the R744 vapour compression rack equipped with a two-phase ejector based on short-term, long-term and unsteady operations

In the case of R744 refrigeration technology, system equipped with a two-phase ejector is one most efficient systems, allowing utilisation an R744-based unit in hot and tropical climates. However, experimental analyses ejector-based have only been performed for performance evaluation, mapping ejectors or validation numerical simulation. Therefore, main goal/scope this paper to enhance knowledge state-of-the-art vapour compression rack ejector, relationship between other components, influence unsteady work on cooling demand. The test campaign was carried out rig capacity 50 kW, high-side pressures from 60 bar 100 temperatures 15 °C 40 °C. analysis conducted three different operating conditions, namely, short-term, long-term, unsteady-state air-conditioning applications. Utilisation influenced instability, especially at internal heat exchanger control. addition, low-pressure lift below 4 allowed control strategy demand operation critical point. For transcritical operation, obtained defined pressure 6 bar.