Efficient fan assembly

1. A fan assembly, comprising:

an external housing;

a bell inlet positioned inside the external housing;

an internal housing positioned inside the external housing, the internal housing including:

an outer internal housing;

an inner internal housing at least partially disposed within the outer internal housing, the inner internal housing defining an internal cavity, and having:

a first diameter at a first end;

a second diameter at a second end; and

a maximum diameter between the first and second ends, the maximum diameter being greater than the first and second diameters, and having a curved exterior surface for defining an annulus between the inner internal housing and the external housing; and

stator blades extending between the inner internal housing and the outer internal housing, the stator blades having an air-foil shape;

wherein the outer internal housing, the inner internal housing, and the stator blades are produced as a single, integral component such that the internal housing is produced as a monolithic part without any welds or attachment features;

an electric motor housed inside the internal cavity defined by the inner internal housing, the electric motor having a motor shaft; and

a fan wheel having a hub coupled to the motor shaft, the fan wheel including fan blades extending from the hub to an inner surface of a wheel cone, the hub having a dome-shape with a diameter matching the first diameter of the inner internal housing.

2. The fan assembly of claim 1 , wherein the internal housing is produced by 3D printing.

3. The fan assembly of claim 1 , wherein the external housing is made of galvanized steel, and the internal housing is made of a material providing spark resistance.

4. The fan assembly of claim 1 , wherein the outer internal housing defines an inner surface that is continuous with the inner surface of the wheel cone.

5. The fan assembly of claim 4 , wherein the inner surface defined by the outer internal housing is inclined at an angle with respect to a central axis of the internal housing.

6. The fan assembly of claim 1 , wherein at least one of the stator blades includes a channel extending from the internal cavity to the outer internal housing.

7. The fan assembly of claim 1 , wherein the annulus increases in size from the maximum diameter of the inner internal housing to an end of the external housing.

8. The fan assembly of claim 1 , wherein the fan assembly is mounted in an array of fan assemblies configured for cooling a data center.

9. An internal housing for a fan assembly, comprising:

an outer internal housing;

an inner internal housing at least partially disposed within the outer internal housing, the inner internal housing defining an internal cavity, and having:

a first diameter at a first end;

a second diameter at a second end; and

a maximum diameter between the first and second ends, the maximum diameter being greater than the first and second diameters, and defining a curved exterior surface for the inner internal housing extending from the first end to the second end; and

stator blades extending between the inner internal housing and the outer internal housing;

wherein the internal housing is produced as a monolithic part without any welds or attachment features.

10. The internal housing of claim 9 , wherein the internal housing is produced by 3D printing.

11. The internal housing of claim 9 , wherein the internal housing is made of a copolymer material providing spark resistance.

12. The internal housing of claim 9 , wherein the outer internal housing defines an inner surface inclined at an angle with respect to a central axis of the internal housing.

13. The internal housing of claim 9 , wherein at least one of the stator blades includes a channel extending from the internal cavity to the outer internal housing.

14. A fan assembly, comprising:

an external housing;

a bell inlet positioned inside the external housing;

an internal housing positioned inside the external housing, the internal housing including:

an outer internal housing;

an inner internal housing at least partially disposed within the outer internal housing, the inner internal housing defining an internal cavity, and having a first diameter at a first end, a second diameter at a second end, and a maximum diameter between the first and second ends, the maximum diameter being greater than the first and second diameters, and having a curved exterior surface for defining an annulus between the inner internal housing and the external housing, the annulus increasing in size by 80% from the maximum diameter of the inner internal housing to an end of the external housing; and

stator blades extending between the inner and outer internal housings;

wherein the internal housing is produced as a monolithic part without any welds or attachment features;

an electric motor housed inside the internal cavity defined by the inner internal housing, the electric motor having a motor shaft; and

a fan wheel having a hub coupled to the motor shaft, the fan wheel including fan blades extending from the hub to an inner surface of a wheel cone.

15. The fan assembly of claim 14 , wherein the bell inlet defines an inlet diameter, the annulus defines an outer diameter, and the outer diameter of the annulus is 50% larger than the inlet diameter.

16. The fan assembly of claim 14 , wherein the internal housing is produced by 3D printing.

17. The fan assembly of claim 14 , wherein the outer internal housing defines an inner surface inclined at an angle with respect to a central axis of the internal housing.

18. A fan assembly, comprising:

an external housing;

a bell inlet positioned inside the external housing;

an internal housing positioned inside the external housing, the internal housing including:

an outer internal housing;

an inner internal housing at least partially disposed within the outer internal housing, the inner internal housing defining an internal cavity, and having:

a first diameter at a first end;

a second diameter at a second end; and

a maximum diameter between the first and second ends, the maximum diameter being greater than the first and second diameters, and having a curved exterior surface for defining an annulus between the inner internal housing and the external housing; and

stator blades extending between the inner internal housing and the outer internal housing, the stator blades having an air-foil shape;

an electric motor housed inside the internal cavity defined by the inner internal housing, the electric motor having a motor shaft; and

a fan wheel having a hub coupled to the motor shaft, the fan wheel including fan blades extending from the hub to an inner surface of a wheel cone, the hub having a dome-shape with a diameter matching the first diameter of the inner internal housing;

wherein the external housing is made of galvanized steel, and the internal housing is made of a material providing spark resistance.