An air-cooled condenser apparatus for condensing a steam flow from a steam turbine wherein the air-cooled condenser apparatus is erected along a vertical axis Z perpendicular to a floor level comprising two orthogonal axes X and Y perpendicular to the axis Z, said air-cooled condenser apparatus comprising a series of condenser modules ACCM(i) with i=1 to NMOD and 1≤NMOD, each condenser module ACCM(i) of said series of condenser modules comprising a series HEXU(j) of delta-type heat exchanger units with j = 1 to UN and UN = 2 or UN = 3, forming a row of UN delta-type heat exchanger units extending along a direction parallel with said axis X, and wherein each delta-type heat exchanger unit of said series HEXU(j) comprises, • a first set of parallel tubes and a second set of parallel tubes that are inclined with respect to said vertical axis Z and are positioned so as to have an opening angle δ between the first set and the second set of parallel tubes comprised in a range 45°≤δ≤65°, and wherein the tubes of said first set and second set of parallel tubes have a tube length TL comprised in a range of 1.5 m<TL<2.5 m, and said tubes comprise fins, • a top duct extending in a direction parallel to said axis Y and connected to an upper end of each tube of said first set of parallel tubes and connected to an upper end of each tube of said second set of parallel tubes, • a first steam/condensate manifold extending in a direction parallel to said axis Y and connected to a lower end of each tube of said first set of parallel tubes, • a second steam/condensate manifold extending in a direction parallel to said axis Y and connected to a lower end of each tube of said second set of parallel tubes, said first steam/condensate manifold and said second steam/condensate manifold have a length PL that is comprised in a range of 8.0 m<PL<13.7 m, characterized in that said air-cooled condenser apparatus further comprises: a series of fans FAN(k) with k=1 to FN and with 2 ≤ FN ≤ 4, and wherein the fans FAN(k) are aligned along an axis parallel with the Y axis and configured to generate an air flow through each delta-type heat exchanger unit of said series HEXU(j),and a support structure configured for positioning the delta-type heat exchanger units of each of the condenser modules ACCM(i) at a height H1, measured along the Z axis, that is equal or larger than four meter above said floor level. • a first set of parallel tubes and a second set of parallel tubes that are inclined with respect to said vertical axis Z and are positioned so as to have an opening angle δ between the first set and the second set of parallel tubes comprised in a range 45°≤δ≤65°, and wherein the tubes of said first set and second set of parallel tubes have a tube length TL comprised in a range of 1.5 m<TL<2.5 m, and said tubes comprise fins, • a top duct extending in a direction parallel to said axis Y and connected to an upper end of each tube of said first set of parallel tubes and connected to an upper end of each tube of said second set of parallel tubes, • a first steam/condensate manifold extending in a direction parallel to said axis Y and connected to a lower end of each tube of said first set of parallel tubes, • a second steam/condensate manifold extending in a direction parallel to said axis Y and connected to a lower end of each tube of said second set of parallel tubes, said first steam/condensate manifold and said second steam/condensate manifold have a length PL that is comprised in a range of 8.0 m<PL<13.7 m, a series of fans FAN(k) with k=1 to FN and with 2 ≤ FN ≤ 4, and wherein the fans FAN(k) are aligned along an axis parallel with the Y axis and configured to generate an air flow through each delta-type heat exchanger unit of said series HEXU(j),and a support structure configured for positioning the delta-type heat exchanger units of each of the condenser modules ACCM(i) at a height H1, measured along the Z axis, that is equal or larger than four meter above said floor level.