This module includes the parts list, design specification, and build description for a rapid build Hello Hub structure, using (readily available) 4-post server racks(link is external) as the primary structural component.
Many of these racks have high strength specifications, offer modular mounting options, and can be shipped flat-packed (will be great for multiple-hub builds). They are generally a slightly smaller footprint than our current spec (3' x 2' instead of 3' x 3'), but this should be ok as we have been working hard to reduce the power consumption of the system and the result is that we have a reduced number of PV panels to hold up.
Additional specs on this 4-post rack: http://goo.gl/bXlzmR(link is external)
|Rack||1||Heavy Duty 4-post standard server rack|
|Beam||2||1.5” x 4” x 9' Steel Square tube, with 1/8” wall thickness|
|Purlin||5||1.5 x 3” x 6' Steel Square tube, with 1/8” wall thickness|
|Panel||3||6' x 3' Metal Roof panels (ribbed or corrugated, high gauge preferred)|
|Fastener||5lb||Self-tapping metal screw 3/4” #12|
|Fastener||5lb||Self-tapping metal screw 1 1/2” #12|
|Rock||100LB||Clean 1” Gravel|
|Concrete||1.5 QY||1.5 QY of Concrete Mix|
|Rebar||100LF||3/8th rebar, 24" grid reinforcement.|
|Bolt||4||Concrete 1/2" bolt or similar, to secure rack to slab.|
|Water||as needed||Water for concrete mixing|
|Paint||1 gallon||Exterior waterproofing paint for rack and bare metal.|
|Braces||4||10' wood 2x4, or bambo or similar. For temporary bracing while concrete sets.|
|Screws||1||1lb wood screws|
|Strapping||1||roll of metal strapping, to secure braces to metal posts|
- Cordless drill or impact driver 18v+ with drill and driver bits
- Hand Level
- Drill bits
- Shovels & Tamper
- Concrete floating tool (diy ok)
- Forming material (scrap wood 4" wide) and stakes.
- Slab Foundation. Prepare Foundation by exavating 4 inches of soil. Fill with gravel to grade and tamp down with tampers. Add forms, rebar grid, and position j-bolts in proper positions to secure rack. Mix and pour concrete into formed area. Float as needed. Let concrete cure, make sure to keep damp if very hot.
- Install rack via securing to set j-bolts.
- Roof pieces is attached to set frame with brackets and self-tapping screws.
- Roof panels are attached to roof pieces with self-tapping screws.
- Equipment panels will be attached to frame as needed with self-tapping screws.
Here's a render of the completed Hello Hub, using the 4-post rapid build structure.