The application of air source heat pumps in cold regions is severely limited by frost accumulation during winter. The frost-free air source heat pump (FFASHP) employs antifreeze solution as an intermediate heat transfer medium between the refrigerant and air, effectively resolving the frosting issue in finned-tube heat exchangers. However, this approach introduces additional energy consumption for solution regeneration and concentration regulation. Conventional thermal regeneration methods require overcoming the latent heat of vaporization of water, whereas freezing concentration circumvents this by utilizing the latent heat of fusion. To investigate the applicability of this method, this study proposes a progressive freeze concentration model to simulate the regeneration dynamics of calcium chloride solution using a vapor-compression refrigeration cycle. Simulation results reveal that the regeneration process can be divided into two stages: an initial period dominated by sensible cooling, and a subsequent phase characterized by ice formation and latent heat removal. The coefficient of performance (COP) declines steadily throughout the process—from approximately 3.8 initially to below 1—mainly due to the increasing thermal resistance induced by ice accumulation. The average COP was found to be around 1.4. Additionally, the evaporation temperature has a significant influence on regeneration performance. Lower evaporation temperatures accelerate ice formation but also reduce energy efficiency. These findings demonstrate the trade-off between regeneration speed and system efficiency, highlighting the importance of staged or optimized operation strategies. The proposed model provides a theoretical foundation for the design and optimization of low-energy regeneration schemes in FFASHP systems.