Solar Micro-Grid

Each year, the Society of Women Engineers participates in a national design challenge in partnership with an engineering firm. Of the project options presented to our team, we elected to partner with S&C Electric to design a sustainable solar energy system for rural Africa. Our team of 12 was tasked with designing a proof of concept system using off-the-shelf components with a load management controller. We also worked to determine the optimal community in which to implement the system and conducted a cost analysis on the feasibility of our design. Throughout the year, I lead sub-teams in understanding the technical requirements for the system and in developing the microcontroller system.

The Hardware

Battery Technology

It was proposed that our system use car batteries as the energy storage bank. The benefit being the fact that car batteries were readily available. The battery sub-team set out to understand the different battery technologies available and what would be optimal for a solar energy system. Although car batteries would be easier to source in Tanzania, sealed deep cycle batteries were selected based on their life span, maintenance requirements, and ease of integrating them into a solar system.

Sizing the System

Tanzania was selected as the target market for our solar system due to its high solar radiance, low GDP, and low political instability. It was determined that the system would be used to support lighting, phone charging, fans, and a TV. These factors in mind, I put together a spread sheet to help balance the amount of expected solar energy stored per day with different scenarios of energy usage. A 4.8 kWh system was specified coupled with 2 x 110-Watt solar panels and 4 batteries. This would allow two outlets to be used as the same time by a household.

The Software

A Microcontroller for Micro-Grid

The teams programming efforts began with the development of pseudo code to meet the needs of the system use scenarios. At a site visit with S&C Electric, our advisors taught us how to use the Connected Components Workbench for programming the micro-controller. I then set about graphically programming our pseudo code and testing it. The program was successfully able to regulate power usage of four different outlets.

The Competition & Beyond

SWE National Conference

I was selected to give the presentation of our work to the panel of judges at the SWE National Conference. Our efforts throughout the year recognized by the judges and we took 2nd place in the event.

Passing the Torch

The work completed to establish the proof of concept design was passed on to the Electrical Engineering department. The following year, a senior design team was selected to pick up were the team left off in the design efforts.