D2 Meeting 11/8

Background info:

• you mentioned last time

• we are still in the process of designing our aeroshell. The goal is to have the shell finalized enough such that we could send out the CNC instructions for the foam mold we will use to layup the shell in january. In the meantime, there will be a lot of design changes. In the past, the array layout was sort of an after thought, and it was basically done by the aeroshell lead as they made the top shell. Since we have y’all working with us on the layout, we are wanting to know how this process can go, and how parallelizable it is.

Questions from Array

• what info do you need from us in order to start helping us with layout?

• what do we need to consider while designing the top shell with the array?

• dimensions for cells: distance between cells + distance between modules (margin of each module)

  • 2mm string-to-string +-0.5 mm

  • parameters of a pannel (sub-arrays): 2-3 mm between edge of cell to edge of panel

    • usually 10 mm for cheaper

• what diodes?

  • follow up with them on that

  • laminated diode

  • 3.5 V drop from schottkey that they have

• if we want custom sensors (RTDs), how can we add it inside the module?

  • thermocouplers from them - thin - need to follow up with them

• can we have our own bypass diodes embedded in the modules?

  • yup

  • but can also have leads stick out from modules for active bypass diodes (w/ mosfets)

• are you sending us modules or whole sub arrays?

  • flexible

• past examples of modules?

  • 200W/kg

  • 1kg/m^2

  • ETFE Polyonofen

  • figerglass sheets or carbon fiberhsheets

• How we should optimize wiring?

• expense of more array area?

  • table has prices

• array cooling + mounting?

  • laminate cells on carbonfiber or fiberglass to support on areas with cells

• example cells & modules for comp?

  • just gotta order extra

• heat sinks?

  • 80*C for the didoes and they’d be fine

Aeroshell:

• What file format should we send you the top shell as?

• As we go through iterations, would it be possible for preliminary layouts to be planned in parallel such that the top-shell design and array layout are finalized around the same time? This would allow us to have feedback between both system in case something changes, such as roll cage position, top shell width, etc.

• How does a curved top-shell change the workflow/cost?

Wot do they need?

• DXF/drawing of Vechicle/topshell

  • can be flexible

• Voltages, num cells, string length

Modeling cells and modules

• current cells as solar cells + diodes

• diff currents for diff levels of shading

• can be used for bypass diodes modeling

• more tutorials online

Curvature of Topshell

• curvature of topshell isn’t a big deal

• but curve means more area → should give them the curve length (more important than not dimensions

• Send Step file, with annotated DXF file, perhaps slides presentation

Action steps from aaray

• ask abt diodes, thermocouplers, strain sensors, ask about table of weights & power

• sudo square for sensors -

• build the irradiance sensors

• send data sheet for sensors

• try out LTSpice sims (https://www.youtube.com/watch?v=0v1lKnc9n8Q)

Top shell holes and mounting

• maybe we drill the shell, but they could laminate the panels onto fiberglassor carbon fiber so we get them as a sheet, so we can bond it onto our composite. In this case, makes it so you don't put your hand through it as we mount it

• Could get test coupons to test heat retention of the shell

12” bend radius max possible, perhaps even tighter. This gets into issue of angle of incidence to the sun

Cells at different angles in series could limit performance

cell: 125mm, gap 2mm, at 62 inches about 12 cells across.

Take gap between cell to edge to half an inch

budgeting

• send them our budget + how we plan to split payment dates