PURPOSE: A rectifier, a one-stage compression-absorption type heat pump system, and a two-stage compression-absorption type heat pump system are provided to control the number of unit modules of a second rectification module, thereby manufacturing a gaseous refrigerant with high purity and refrigerant-absorbent mixed solution at a low concentration by using the refrigerant-gas mixture at a high concentration. CONSTITUTION: A rectifier comprises a first rectification module(10) and a second rectification module(20). The first rectification module includes a first heating member(11), a first cooling member(12), and a first heat transmitting member(130). The first heating member heats a refrigerant-absorbent mixture, thereby evaporating refrigerant from the mixture. The first cooling member cools and condenses the absorbent included in the evaporated refrigerant, thereby removing the absorbent from the evaporated refrigerant. The first heat transmitting member heat exchanges the condensed absorbent and the evaporated refrigerant and evaporates the refrigerant included in the condensed absorbent, thereby making the evaporated refrigerant flow to the first cooling member. [Reference numerals] (AA) Compressor; (BB) High-purity gaseous refrigerant; (CC,FF,KK) Hot water; (DD,GG) Cooling water; (EE,HH) Absorbent; (II) High-density refrigerant-absorbent mixture; (JJ) Expansion device; (LL) Absorber; (MM) Weak solution of refrigerant-absorbent mixture |