Refrigerant injection for heat pump systems in cold regions: advancements, challenges and future perspectives

• Published in: International journal of refrigeration Vol. 155; pp. 7 - 22
• Main Authors: Zhang, Zhenya, Cao, Haoning, Jin, Tingxiang, Lv, Zijian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2023
• Subjects: Compresseur; Compressor; Configuration du cycle; Control strategy; Cycle configuration; Injection de frigorigène; Injection port; Inter-stage structure; Port d'injection; Refrigerant injection; Stratégie de regulation; Structure inter-étage; Refrigerant injection; Injection port; Compresseur; Structure inter-étage; Port d'injection; Injection de frigorigène; Inter-stage structure; Compressor; Control strategy; Configuration du cycle; Cycle configuration; Stratégie de regulation
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2023.09.006

•Refrigerant injection (RI) at system and component level respectively.•RI type, cycle configuration, control strategies and new refrigerants are debated.•Compressor type, injection port and inter-stage structures of RI are reported.•New applications using RI, such as combining with green energy, will be explored. Refrigerant injection (RI) technique has been extensively used in heat pump systems to reduce the exhaust temperature and raise the heating capacity. Recently, there have been enormous advances in the refrigerant injection for heat pump systems. However, few existing studies have systematically summarized and evaluated the recent advancements in these related studies, as well as the challenges and future recommendations. This study presents a comprehensive review of the recent advances in refrigerant injection heat pump systems applied in cold regions. The related studies are mainly reviewed from two aspects: the system level and the component level. The advances at system level mainly include refrigerant injection type, cycle configurations, control strategies and alternative refrigerants. Subsequently, the advances at component level with respect to the compressor type, injection port, and inter-stage structures are discussed. Besides, the research direction for RI technique will explore the use of refrigerant injection in new applications as the HVAC industry continues to shift towards more sustainable and efficient practices.