A co-fired generator for use in a continuous-cycle absorption heating and cooling system may provide heat to the interior of an annulus chamber from a first heat exchanger, such as a firetube heat exchanger, supplemented by heat to the exterior of the annulus chamber from a second heat exchanger containing fluid heated by an external source. Some embodiments may circulate fluid heated in a solar-heated collector through the second heat exchanger. Other embodiments may route exhaust gas from a combustion engine through the second heat exchanger. The second heat exchanger may be provided with a plurality of fins to increase the surface area available for thermal transfer between the heated fluid and the annulus chamber.

A refrigeration cycle apparatus (50) includes: a main refrigerant circuit (21) having a compressor (1), a radiator (2), a first expansion mechanism (5), a second expansion mechanism (6), and an evaporator (4); an injection passage (22) for supplying an intermediate-pressure refrigerant to an injection port 1c of the compressor 1; and a water circuit (30) through which water to be heated in the radiator (2) flows. The refrigeration cycle apparatus (50) includes a sub heat exchanger (3) for cooling the water in the water circuit (30) by exchanging heat between the refrigerant in the injection passage (22) and the water to be heated in the radiator (2).