NOVELTY - The apparatus has a heat source (102) for energizing a boiler (101) to vaporize working fluid in high-temperature and high-pressure gaseous state. A direction controllable three-way valve (18) is provided between the boiler and an expansion turbine (111). Another direction controllable three-way valve (19) is provided between another expansion turbine (11) and an ejector (12). The three-way valves are operable to direct the working fluid along selected direction for executing a power generation and refrigeration mode, a refrigeration mode, a power generation mode or an idle mode.    USE - Apparatus for generating power and refrigeration from low-grade heat e.g. industrial waste heat, solar thermal heat and geothermal heat (all claimed).    ADVANTAGE - The apparatus changes flow directions of working fluid in the direction controllable three-way valves, so that one of the power generation and refrigeration mode, the refrigeration mode, the power generation mode or the idle mode is executed, thus using low-grade heat in multiple manners, and hence utilizing sufficiently energy, saving energy and reducing emission of green house gas. The apparatus includes subsonic mixed gaseous working fluid that leaves from the ejector into a hot channel of a heat exchanger, so that the residual heat is recovered by preheating the liquid working fluid out of a pressure pump, thus reducing loads on a heating module and a condenser module. The apparatus allows residual heat of medium-pressure gaseous working fluid at an outlet of the expansion turbine or ejector to preheat liquid working fluid at an inlet of a heating module, thus increasing thermal efficiency of the apparatus.    DETAILED DESCRIPTION - The heat source is industrial waste heat source, solar thermal heat source or geothermal heat source. The working fluid is an organic hydrocarbon, an inorganic small molecular compound such as such as carbon dioxide or ammonia, or a chlorofluorocarbon.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a power and refrigeration generating apparatus.    Expansion turbines (11, 111)    Ejector (12)    Direction controllable three-way valves (18, 19)    Boiler (101)    Heat source (102)