Heating systems with unhoused centrifugal fan and wraparound heat exchanger
A heating system with wraparound heat exchanger is disclosed. The system includes a centrifugal fan that expels air radially into a plenum space. A heat exchanger tube is placed in the plenum space, thereby heating the air in the plenum space before it exits an assembly cabinet. The heat exchanger tube can have various configurations, including non-horizontal configurations so as to allow condensate to drain from the heat exchanger tubes.
1. A heat exchanger assembly comprising:
an outer housing comprising an upstream section and a lower section, wherein the upstream section comprises an evaporator, and wherein the lower section comprises a condenser unit;
a burner assembly;
a heat exchanger tube comprising a first section positioned at a first distance from the burner assembly comprising an ingress disposed adjacent to a first side of the heat exchanger assembly, a second section positioned at a second distance from the burner assembly comprising an egress disposed adjacent to the first side of the heat exchanger assembly, and a curved section disposed between the first section and the second section, wherein a first end of the first section connects to a first end of the curved section, wherein a first end of the second section connects to a second end of the curved section, wherein the first section, the second section, and the curved section form a U-shape extending from the ingress to the egress, and wherein the second distance is greater than the first distance; and
a centrifugal fan positioned between the first section and the second section and configured to pull in air from a fan inlet and disperse air across the first section, the second section, and the curved section;
wherein the heat exchanger tube loops around the centrifugal fan; and
wherein a center portion of the centrifugal fan is positioned at a third distance from the first section and at a fourth distance from the second section, wherein the fourth distance is greater than the third distance.
2. The heat exchanger assembly of claim 1 , wherein the centrifugal fan is a plenum fan and the heat exchanger tube is disposed within a plenum space of the plenum fan.
3. The heat exchanger assembly of claim 2 , wherein the plenum fan is a direct drive single inlet unhoused plenum fan.
4. The heat exchanger assembly of claim 1 , further comprising a cabinet that contains the heat exchanger tube and the centrifugal fan, the cabinet comprising at least one cabinet inlet positioned proximate the fan inlet and one or more cabinet outlets.
5. The heat exchanger assembly of claim 1 , wherein the first section and the second section are parallel with respect to one another.
6. The heat exchanger assembly of claim 5 , wherein the first section and the second section have a non-zero angle with respect to horizontal when viewed from a side of the heat exchanger tube.
7. The heat exchanger assembly of claim 1 , wherein:
the first section has a first angle with respect to horizontal when viewed from a side of the heat exchanger tube; and
the second section has a second angle with respect to horizontal when viewed from a side of the heat exchanger tube, the second angle being a different angle than the first angle.
8. The heat exchanger assembly of claim 7 , wherein the first angle is 0°.
9. The heat exchanger assembly of claim 7 , wherein the second angle is a decline angle, wherein a first portion of the second section proximate the curved section is higher with respect to horizontal than a second portion of the second section proximate an ingress portion of the heat exchanger tube.
10. The heat exchanger assembly of claim 1 , wherein the first section and the second section are substantially straight.
11. The heat exchanger assembly of claim 10 , wherein the curved section forms an angle of less than 180°.
12. The heat exchanger assembly of claim 1 , wherein the curved section forms an angle of less than 180°.
13. A heating system comprising:
a burner assembly;
a centrifugal fan comprising a fan inlet;
a heat exchanger tube positioned at least partially around the centrifugal fan, the heat exchanger tube comprising a first section positioned at a first distance from the burner assembly comprising an ingress disposed adjacent to a first side of the heating system, a second section positioned at a second distance from the burner assembly comprising an egress disposed adjacent to the first side of the heating system, and a curved section disposed between the first section and the second section, wherein a first end of the first section connects to a first end of the curved section, wherein a first end of the second section connects to a second end of the curved section, wherein the first section, the second section, and the curved section form a U-shape extending from the ingress to the egress, and wherein the second distance is greater than the first distance;
wherein a center portion of the centrifugal fan is positioned at a third distance from the first section and at a fourth distance from the second section, wherein the fourth distance is greater than the third distance;
a cabinet that contains the centrifugal fan and at least a portion of the heat exchanger tube, the cabinet comprising an air inlet positioned proximate the fan inlet and an air outlet, wherein the centrifugal fan is configured to disperse air radially from the center portion of the centrifugal fan and across at least a portion of the heat exchanger tube;
wherein a flow path through the heat exchanger tube loops around the centrifugal fan; and
an outer housing comprising an upstream section and a lower section, wherein the upstream section comprises an evaporator, and wherein the lower section comprises a condenser unit.
14. The heating system of claim 13 , wherein the first section and the second section each extend perpendicular to the first side of the heating system.
15. The heating system of claim 13 , wherein the first section and the second section are parallel with respect to one another.
16. The heating system of claim 13 , wherein the first section and the second section have a non-zero angle with respect to horizontal when viewed from a side of the heat exchanger tube.
17. The heating system of claim 13 , wherein:
the first section has a first angle with respect to horizontal when viewed from a side of the heat exchanger tube; and
the second section has a second angle with respect to horizontal when viewed from a side of the heat exchanger tube, the second angle being a different angle than the first angle.
18. The heating system of claim 17 , wherein the second angle is a decline angle, wherein a first portion of the second section proximate the curved section is higher with respect to horizontal than a second portion of the second section proximate an ingress portion of the heat exchanger tube.
19. The heating system of claim 13 , wherein:
the centrifugal fan is a plenum fan;
the cabinet defines a plenum space around the centrifugal fan; and
the heat exchanger tube is disposed within the plenum space.