Effects of vapor injection modes on the heating performance of heat pumpsBin Liu, Lin Chai, Aiqiang Chen, Fuhui Tang, Khellil Sefiane and Georges E.I. AchkarEur. Phys. J. Appl. Phys., 86 3 (2019) 30902DOI: https://doi.org/10.1051/epjap/2019190126