Vapor-injection heat pump (VIHP) technology has become a research hotspot in the field of energy in recent years owing to its advantages of high efficiency

energy saving

and environmental protection under low-temperature conditions. The current research status of VIHP technology is stated based on the existing literature. The application type

compressor type

implementation method

and optimization research are discussed in depth. The advantages and disadvantages of improving the performance of VIHP systems are compared and analyzed. Finally

in combination with existing research problems

the development trend of VIHP is envisioned

thereby providing a reference for future research applications of VIHP technology.