Performance analysis of a novel hybrid vapor injection cycle with subcooler and flash tank for air-source heat pumps

• Published in: International journal of refrigeration Vol. 74; pp. 540 - 549
• Main Authors: Qi, Hongjie, Liu, Fuya, Yu, Jianlin
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Ltd 01.02.2017; Elsevier Science Ltd
• Subjects: Ambient temperature; Amélioration; Ejection; Ejector; Energy efficiency; Enhancement; Exergy; Heat pump; Heat pumps; Heating; Injection; Performance enhancement; Pompe à chaleur; Pumps; Simulation; Thermodynamics; Vapors; Éjecteur; Pompe à chaleur; Heat pump; Ejector; Injection; Performance; Enhancement; Éjecteur; Amélioration
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2016.11.024

•A novel hybrid vapor injection cycle (HVIC) with subcooler and flash tank is proposed.•The performance of HVIC can be improved due to an application of an ejector.•The HVIC using R32 and R290 are evaluated with energy and exergy analysis methods.•COP and volumetric heating capacity of HVIC are promoted compared to baseline cycles. In this paper, a novel hybrid vapor injection cycle (HVIC) with subcooler and flash tank for air-source heat pumps is proposed. In the HVIC, an ejector is applied to realize the advantages of both the subcooler and flash tank vapor injection, which can efficiently reduce the irreversible thermodynamic loss and improve the system performance, especially at low ambient temperature conditions. The performance enhancement potential of HVIC is compared with conventional subcooler vapor injection cycle (SVIC) and flash tank vapor injection cycle (FTVC) using cycle simulations. The simulation results indicated that for the HVIC using R290 as refrigerant, the coefficient of performance (COP) and the volumetric heating capacity can be increased by 2.8–3.3% and 6.4–8.8% compared to the SVIC system, 1.1–2.0% and 3.2–6.0% compared to the FTVC system, respectively. In addition, improving the ejector efficiencies and adjusting the injection pressure could also enhance the performance of HVIC. Exergy analysis indicates that the total exergy destruction for the HVIC is lower than that of SVIC and FTVC due to the application of an ejector, and therefore resulting in higher exergy efficiency. Overall, the HVIC could be more effective to enhance heating capacity and system efficiency.