Vacuum spray boiler
A heat exchanger system, in particular a vacuum spray boiler, cools a hot fluid by spraying a coolant onto chambers carrying the hot fluid. This process may be performed in i) a vacuum, as in space, ii) atmospheric pressure, as on a launch pad of a space vehicle, or iii) any pressure therebetween. The heat exchanger system may incorporate a plate-fin heat exchanger. A coolant spray apparatus, used for spraying the coolant, and the heat exchanger are integrated within a vacuum chamber. The coolant, subsequent to changing to a vapor state after being sprayed onto the heat exchanger, may be exhausted to outside the system.
1 . A vacuum spray boiler cooling system for cooling a fluid, the system comprising:
a vacuum tank having an enclosed space at least partially surrounded by a casing;
components integrated within the vacuum tank, the components comprising:
a fluid inlet and a fluid outlet penetrating the casing, the fluid inlet and the fluid outlet for carrying the fluid through the casing;
a heat exchanger in the enclosed space;
a coolant spray apparatus including one or more spray nozzles in the enclosed space, the coolant spray apparatus for spraying coolant onto the heat exchanger; and
a coolant inlet and a coolant exhaust port at least partially penetrating the casing, the coolant inlet for carrying the coolant to the coolant spray apparatus and the coolant exhaust port for carrying vaporized coolant away from the enclosed space; and
an exhaust vent connected to the coolant exhaust port and in thermal contact with a portion of the components, the exhaust vent to release the vaporized coolant from the system.
2 . The vacuum spray boiler cooling system of claim 1 , wherein the casing includes a lid and sides, and wherein the lid includes the coolant inlet.
3 . The vacuum spray boiler cooling system of claim 2 , wherein the lid includes the coolant spray apparatus.
4 . The vacuum spray boiler cooling system of claim 3 , wherein the coolant spray apparatus protrudes from the lid.
5 . The vacuum spray boiler cooling system of claim 1 , wherein the heat exchanger is a plate-fin heat exchanger.
6 . The vacuum spray boiler cooling system of claim 5 , wherein the plate-fin heat exchanger comprises serpentine-shaped chambers to carry the fluid.
7 . The vacuum spray boiler cooling system of claim 1 , wherein the components further comprise inlet tubing connected to the fluid inlet, wherein the thermal contact of the exhaust vent with the portion of the components is based on ambient conditions surrounding the system, from the fluid in the inlet tubing to the exhaust vent.
8 . The vacuum spray boiler cooling system of claim 1 , wherein the thermal contact of the exhaust vent with the portion of the components comprises conduction heating from the heat exchanger to the exhaust vent.
9 . The vacuum spray boiler cooling system of claim 1 , wherein the casing is aluminum.
10 . The vacuum spray boiler cooling system of claim 1 , wherein the fluid is hydraulic fluid and the coolant is water.
11 . The vacuum spray boiler cooling system of claim 1 , wherein the coolant spray apparatus is in thermal contact with the heat exchanger so as to prevent coolant freezing at the nozzles of the spray apparatus.
12 . A vacuum spray boiler cooling system comprising:
a vacuum tank having a casing that encloses an internal space;
a plate-fin heat exchanger disposed in the internal space and configured to carry a working fluid through finned chambers;
a coolant spray apparatus mounted to a portion of the casing and configured to deliver a coolant through nozzles into the internal space;
a coolant inlet for supplying the coolant to the coolant spray apparatus;
a coolant exhaust port configured to remove vaporized coolant from the internal space; and
one or more thermally conductive fins or members configured to conduct heat from the working fluid or the heat exchanger to the nozzles to inhibit coolant freezing at the nozzles.
13 . The system of claim 12 , wherein the nozzles are mounted to protrude into the internal space and are connected to the coolant inlet via a coolant channel integrated within the portion of the casing.
14 . The system of claim 12 , wherein the casing includes one or more sight glasses configured to permit visual inspection of spray and boiling inside the internal space.
15 . The system of claim 12 , wherein the one or more thermally conductive fins are configured to provide thermal coupling between the heat exchanger and the nozzles.
16 . The system of claim 12 , wherein the coolant spray apparatus comprises nozzles oriented to direct coolant onto the finned chambers of the heat exchanger.
17 . The system of claim 12 , wherein the coolant exhaust port is thermally coupled to both the heat exchanger and a flow path carrying the working fluid via conduction, convection, or radiation, depending on ambient pressure.
18 . The system of claim 12 , wherein the plate-fin heat exchanger comprises herringbone or serrated fins to enhance surface area for heat exchange.
19 . The system of claim 12 , wherein the coolant comprises a water-based mixture stored in a tank external to the system and introduced under residual tank pressure.
20 . The system of claim 12 , wherein the heat exchanger, the coolant spray apparatus, the coolant inlet, the coolant exhaust port, and the nozzles are integrated into a single monolithic structure.