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 . <EOS>