The use of low-temperature heat (between 50 and 90degreesC) is studied to drive absorption systems in two different applications: refrigeration and heat pump cycles. Double- and triple-stage absorption systems are modelled and simulated, allowing a comparison between the absorbent-refrigerant solutions H2O-NH3, LiNO3-NH3 and NaSCN-NH3. The results obtained for the double-stage cycle show that in the refrigeration cycle the LiNO3-NH3 solution operates with a COP of 0.32, the H2O-NH3 pair with a COP of 0.29 and the NaSCN-NH3 solution with a COP of 0.27, when it evaporates at -15degreesC, condenses and absorbs refrigerant at 40degreesC and generates vapour at 90degreesC. The results are presented for double- and triple-stage absorption systems with evaporation temperatures ranging between -40 and 0degreesC and condensation temperatures ranging from 15degreesC to 45degreesC. The results obtained for the double-stage heat pump cycle show that the LiNO3-NH3 solution reaches a COP of 1.32, the NaSCN-NH3 pair a COP of 1.30 and the H2O-NH3 mixture a COP of 1.24, when it condenses and absorbs refrigerant at 50degreesC, evaporates at 0degreesC and generates vapour at 90degreesC. For the double- and triple-stage cycles, the results are presented for evaporation temperatures ranging between 0 and 15degreesC. The minimum temperature required in the generators to operate the refrigeration and heat pump cycles are also presented. Copyright (C) 2002 John Wiley Sons, Ltd.