Numerical assessment of the dynamic behavior of a solar-driven jet-ejector refrigeration system equipped with an adjustable jet-ejector

• Published in: International journal of refrigeration 2021-01, Vol.121, p.168-182
• Main Authors: Galindo, José, Dolz, Vicente, Tiseira, Andrés, Ponce-Mora, Alberto
• Format: Article
• Language: English
• Subjects: Adjustable jet-ejector; Boundary conditions; Comportement dynamique; Computational fluid dynamics; Dynamic behavior; Dynamic response; Efficacité énergétique; Energy efficiency; Environmentally friendly refrigerants; Fluid dynamics; Frigorigènes respectueux de l’environnement; Froid solaire; Froid à éjecteur à jet; Heat transfer; Jet-ejector refrigeration; Numerical analysis; Performance enhancement; Refrigeration; Solar collectors; Solar energy; Solar refrigeration; Storage tanks; Temperature; Thermal storage; Éjecteur à jet réglable
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2020.10.019

•The dynamic behavior of an adjustable jet-ejector refrigeration system is assessed.•A thermal storage system is considered to cope with variable solar irradiation.•The influence of two different jet-ejector architectures is evaluated using R1234yf.•The transient response is computed under real climatic conditions. In the present paper, the mid-term performance of two different architectures of a solar-driven jet-ejector refrigeration system is numerically compared: the first one is fitted with a fixed-geometry jet-ejector while the second one is equipped with an adjustable spindle that modifies the jet-ejector area ratio. The jet-ejector behavior has been predicted with a validated computational fluid dynamics approach and the dynamic response of the overall system accounts for transient effects in a small parabolic trough collector and a hot thermal storage tank. The investigation shows that the adjustable jet-ejector allows for continuous and smooth operation in a much wider range of outdoor conditions. Additionally, it enables more efficient management of the thermal level in the hot storage system. As a result, the adjustable refrigeration system improves the performance indicators in all the warm months of the typical meteorological year under evaluation. The maximum improvement potential is found in May; the fixed-geometry system provides an average COPthof 0.34 while the adjustable system reaches an average COPthof 0.48 considering the same boundary conditions in both cases.