A heat recovery system arranged to generate a thermal input to a first closed-loop system configured as a first closed-loop thermodynamic Rankine cycle system arranged to convert waste heat from a heat generating unit into electrical energy, said heat recovery system comprises a second closed-loop system configured as a second closed-loop thermodynamic Rankine cycle system arranged to convert heat in at least one first heat stream generated by exhaust gases produced in the heat generating unit's exhaust gas system into a first batch of electrical energy, the second closed-loop system comprises a circulating second system working medium and a first heat exchanger in which said second system working medium is arranged to vaporize to become a vapour by a transfer of heat from said at least one first heat stream to the second system working medium a turbine arranged to expand said second system working medium and produce energy to be extracted as the first batch of electrical energy, a second heat exchanger in which said second system working medium is arranged to pass through and to condensate to become a liquid, and a third closed-loop system comprising a circulating third system working medium arranged to circulate in said second heat exchanger, the third system working medium is in liquid phase and is not arranged to change phase during the circulation in the third closed-loop system and is arranged to act as a condensation medium of said second system working medium, wherein the condensation enthalpy of the vaporised second system working medium is transferred to said third system working medium and increasing its temperature, wherein the heat recovery system is characterized in that the third closed-loop system is arranged such that heat from said third system working medium is used as the thermal input to said first closed-loop thermodynamic Rankine cycle system, and wherein the third closed-loop system comprises an arrangement, defined as a second arrangement (11, 14), for controlling the circulation and/or pressurization of said third system working medium through the second heat exchanger, wherein the second closed-loop system further comprises a first control arrangement (8, 12) for controlling the circulation and/or pressurization of said second system working medium and wherein said first control arrangement (8, 12) is arranged to control the pressure of said second system working medium directly after said turbine to be above atmospheric pressure. a second closed-loop system configured as a second closed-loop thermodynamic Rankine cycle system arranged to convert heat in at least one first heat stream generated by exhaust gases produced in the heat generating unit's exhaust gas system into a first batch of electrical energy, the second closed-loop system comprises a circulating second system working medium and a first heat exchanger in which said second system working medium is arranged to vaporize to become a vapour by a transfer of heat from said at least one first heat stream to the second system working medium a turbine arranged to expand said second system working medium and produce energy to be extracted as the first batch of electrical energy, a second heat exchanger in which said second system working medium is arranged to pass through and to condensate to become a liquid, and a circulating second system working medium and a first heat exchanger in which said second system working medium is arranged to vaporize to become a vapour by a transfer of heat from said at least one first heat stream to the second system working medium a turbine arranged to expand said second system working medium and produce energy to be extracted as the first batch of electrical energy, a second heat exchanger in which said second system working medium is arranged to pass through and to condensate to become a liquid, a third closed-loop system comprising a circulating third system working medium arranged to circulate in said second heat exchanger,