A thermodynamic cycle apparatus, in particular an organic Rankine cycle apparatus, comprising: a working medium; an evaporator for evaporating and, optionally, additionally superheating the working medium; an expansion machine for generating mechanical energy while expanding the evaporated working medium; a condenser for condensing and, optionally, additionally subcooling the working medium, in particular the working medium expanded in the expansion machine; and a pump for pumping the condensed working medium to the condenser when the thermodynamic cycle apparatus is in operation; wherein the evaporator is located on a lower level than the condenser, such that, prior to starting the pump, the condensed working medium can flow from the condenser to the evaporator by force of gravity and the working medium can circulate in a closed circuit via the evaporator and the condenser, whereby at least a predetermined minimum head height of the liquid working medium can be provided at the pump; characterized in that the thermodynamic cycle apparatus is further configured to provide the predetermined minimum head of the liquid working medium at the pump by means of: a reduction of a pressure in the condenser by cooling the condenser, and thereafter increasing the pressure in the condenser by means of (i) lowering a speed of a fan of the condenser and/or by means of (ii) reducing a cooling water mass flow or an air mass flow through the condenser and/or by means of (iii) increasing a temperature of the cooling water mass flow or the air mass flow through the condenser. a working medium; an evaporator for evaporating and, optionally, additionally superheating the working medium; an expansion machine for generating mechanical energy while expanding the evaporated working medium; a condenser for condensing and, optionally, additionally subcooling the working medium, in particular the working medium expanded in the expansion machine; and a pump for pumping the condensed working medium to the condenser when the thermodynamic cycle apparatus is in operation; wherein the evaporator is located on a lower level than the condenser, such that, prior to starting the pump, the condensed working medium can flow from the condenser to the evaporator by force of gravity and the working medium can circulate in a closed circuit via the evaporator and the condenser, whereby at least a predetermined minimum head height of the liquid working medium can be provided at the pump; characterized in that the thermodynamic cycle apparatus is further configured to provide the predetermined minimum head of the liquid working medium at the pump by means of: a reduction of a pressure in the condenser by cooling the condenser, and thereafter increasing the pressure in the condenser by means of (i) lowering a speed of a fan of the condenser and/or by means of (ii) reducing a cooling water mass flow or an air mass flow through the condenser and/or by means of (iii) increasing a temperature of the cooling water mass flow or the air mass flow through the condenser. a reduction of a pressure in the condenser by cooling the condenser, and thereafter increasing the pressure in the condenser by means of (i) lowering a speed of a fan of the condenser and/or by means of (ii) reducing a cooling water mass flow or an air mass flow through the condenser and/or by means of (iii) increasing a temperature of the cooling water mass flow or the air mass flow through the condenser.