A new trend for the development of extremely low-potential thermal energy recovery systems is discovered, based on the chemisorption heat pumps with heterogeneous exoergic chemical semi-cycle. Some notes upon the endogeneous compensatory process of the large-scale chemisorption heat pump systems and its comparative efficiency to the exogenous one are included. A mathematical model based on the thermodynamic efficiency coefficients is used. Chemisorption heat pump systems allow thermal energy recovery up to 100 % and more. The study gives some phenomenal advantages of the chemisorption heat pump systems.