Abstract: A power plant comprising combustion means for generating heat for use in a power plant with at least two hot gas engines, comprising first and second working fluid spaces, reciprocating means for varying the volume of working fluid spaces, heating means adjacent said first working fluid space, a source of cooling fluid, first conduit means connecting said source of cooling fluid and said cooling means to convey cooling fluid from said source of cooling fluid to said cooling means to cool working fluid in said second working fluid space and means for conveying the products of combustion from said combustion means to the heating means to heat working fluid in said first working fluid space; second conduit means in communication with the cooling means one said hot gas engine and the combustion means to convey cooling fluid from the cooling means of said one hot gas engine to the combustion means for participation in combustion therein, the cooling means of said second hot gas engine being independent of the comb