Solar Array Area & Canopy Research  - MS16

Owned by Liam Ramlogan
Last updated: Nov 19, 2024
3 min read

Motivation:

With the end of the last competition the ASC has updated their regulations in terms of the sizing of the aerobody. To line up with WSC they have extended the max length and solar array size

Task Description:

What we have found in research is that ideally the length of our canopy should be 6x our height. This obviously isn’t possible but we need to find the ideal length of canopy and width of roof to accommodate for our solar while being as efficient as possible.

Requirements/goals:

  1. Roof space for solar panels must accommodate for 6m^2 while leaving 1 inch gap between the solar panel and any edge/curve

  2. Canopy width must accommodate for occupancy cell while minimizing the width

  3. Canopy has to be placed relative to the occupancy cell and any extensions to length should be made in the positive Z direction (forward/solidworks coordinates)

Fixed dimensions:

Max roof length: 5.7m

Solar array size: 6m^2

Single solar cell area: 125mmx125mm

Occupancy cell CAD will be provided to determine min canopy width and length

Strategy:

In order to save time and resources when optimizing the roof layout, we can make some assumptions:

Assumption 1: Increasing the width of the aerobody will not have an impact on the coefficient of drag (Cd) of the car.

  • It will increase the frontal area, which, along with the Cd, determines total drag force on the car.

  • We can use this assumption to approximate the change in drag force on the car as a result of increasing width.

Assumption 2: Increasing canopy length will reduce the Cd

  • This will have no effect on the frontal area

Assumption 3: Frontal area of the aerobody can be approximated using rectangles: 

Assumption 4: Drag force can be described using this equation:

 

Then, following these steps, we can obtain a model to analyze the optimal width of the aerobody and the resulting length of the canopy:

  1. Separate the canopy geometry from the aerobody geometry

  2. Determine Cd of canopy as a function of the ratio between canopy length & height (L/h)

    1. This doesn’t have to be determined experimentally, as we can approximate a curve given to us by an aero textbook (The Leading Edge by Goro Tamai)

  1. Determine drag force of canopy as a function of Cd (where Cd is a function of L/h, and A, p, V are all constant)

  2. Relate reduction in aerobody frontal area to a reduction in canopy length

    1. While keeping available area for solar cells > 6 m^2, shorten/lengthen width of aerobody and record/plot resultant length of canopy to acquire a function for aerobody width in terms of canopy length.

  3. Determine drag force of aerobody as a function of A ( Cd, p, V are all constant)

  4. Find total drag force equation as a sum of equations 3 and 4

    1. Drag force of the canopy should be around 2-5 N, and drag force of the aerobody should be around 22-28 N (in this ballpark)