Abstract: The invention relates to a single-stage ammonia-water absorption refrigeration machine in a batch process without solution pump and without rectification, consisting of a generator (1) with pressure reducer (29) and solution concentration optimization (3), absorber (14), condenser (25), evaporator (24), wherein the generator (1) together with a back-cooled input vessel (3) and the pressure reducer form a structural and pressure unit, in which the pressure reducer (29), at the start of each operating cycle, reduces the generator pressure below the absorber pressure, in such a way that from there via a check valve (69) solution flows in the back-cooled generator input vessel (3), fills it, and from there the solution gradually flows, following gravity, into a hot zone (1), which advantageously but not necessarily consists of a preheating zone (11) that is heated by the absorber (18) and an externally heated hot zone (12), where ammonia vapor is formed, which is directed by a siphon duct (8) from below through t