Air cooled condenser and related methods
A vertical bundle air-cooled heat exchanger, a finned tube assembly for an air cooled condenser and method for forming the same, and a system for removing thermal energy generated by radioactive materials. In one aspect, an air cooled condenser sized for industrial and commercial application includes an inlet steam distribution header for conveying steam, a condensate outlet header for conveying condensate, an array of tube bundles each having a plurality of finned tube assemblies having a bare steel tube with an exposed outer surface and a set of aluminum fins brazed directly onto the tube by a brazing filler metal. The steel tubes may be spaced apart by the aluminum fins and have an inlet end fluidly coupled to the inlet steam distribution header and an outlet end fluidly coupled to the outlet header. A forced draft fan may be arranged to blow air through the tube bundles.
1. A system for removing thermal energy generated by radioactive materials comprising:
an air-cooled heat exchanger defining a vertical axis and comprising a vertically oriented shell defining a cavity containing a plurality of heat exchange tubes fluidly coupled between a top fluid inlet header and a bottom fluid outlet header;
the air-cooled heat exchanger comprising a heat rejection closed-loop fluid circuit comprising a tube-side fluid path, a coolant fluid flowing through the heat rejection closed-loop fluid circuit, the heat rejection closed-loop fluid circuit thermally coupled to the radioactive materials so that thermal energy generated by the radioactive materials is transferred to the coolant fluid; and
the air-cooled heat exchanger comprising a shell-side fluid path inside the shell having a first air inlet formed through the shell, a second air inlet formed through the shell, and an air outlet formed through the shell, the first air inlet located at a first elevation, the second air inlet located at a second elevation, and the air outlet located at a third elevation, the second elevation greater than the first elevation and the third elevation greater than the second elevation, the air-cooled heat exchanger transferring thermal energy from the coolant fluid flowing through the tube-side fluid path to air flowing through the shell-side fluid path.
2. The system of claim 1 , wherein the tube-side fluid path comprises internal cavities of the plurality of heat exchange tubes, the plurality of heat exchange tubes located within the shell-side fluid path.
3. The system of claim 2 , wherein the plurality of heat exchange tubes form a tube bundle having a vertical longitudinal axis, the heat exchange tubes being straight in configuration and extending along the vertical longitudinal axis.
4. The system of claim 3 , wherein the tube bundle comprises finned tube sections of heat exchange tubes and a non-finned tube sections of heat exchange tubes.
5. The system of claim 4 , wherein the finned tube sections and the non-finned tube sections alternate along the longitudinal axis.
6. The system of claim 5 , wherein the first air inlet, the second air inlet, and the air outlet are transversely aligned with one of the non-finned tube sections.
7. The system of claim 6 , wherein a first one of the finned tube sections is located between the first and second air inlets, and a second one of the finned tube sections is located between the second air inlet and the air outlet.
8. The system of claim 3 , further comprising a vertically-extending shroud forming a shroud cavity, a majority of a length of the shell of the air-cooled heat exchanger being positioned inside the shroud cavity.
9. The system of claim 8 , wherein the first air inlet and the second air inlet form passageways transverse to the longitudinal axis of the tube bundle from outside ambient air through the shroud and shell into the shell-side fluid path.
10. The system of claim 9 , wherein the first and second air inlets are formed by conduits so that all incoming ambient air flows into the shell-side fluid path and not into the shroud cavity.
11. The system of claim 8 , wherein an upper portion of the shroud cavity defines a shroud air outlet plenum circumferentially surrounding the air outlet located proximate to a top of the shell.
12. The system of claim 11 , wherein the shroud air outlet plenum is diametrically enlarged having a larger diameter than portions of the shroud immediately beneath the shroud air outlet plenum.
13. The system of claim 12 , further comprising a chimney disposed at top of the shroud, the chimney forming a passageway from the shroud outlet plenum to an ambient environment.
14. The system of claim 13 , further comprising a blower positioned in the chimney, the blower configured and operable to draw ambient air through the first and second air inlets into the shell cavity and upwards along the shell-side fluid path through the air outlet.
15. The system of claim 14 , wherein the blower discharged the ambient air to atmosphere through a top of the chimney.