Our Solution The first task that our team had to accomplish was designate the primary and secondary functional requirements, which are outlines in Table 1 below. Table 1: The primary and secondary functional requirements for the to be designed system From this the Human Harvester team was able to outline a basic cycle for our system to execute. The basic cycle of the system that converts human energy to usable electricity is below in Figure 1. Figure 1: The original cycle of our system, this is the system in it’s simplest form Background - Energy Crisis Fossil fuels currently supply more than 85% of the energy consumed by US citizens [1]. As oil supplies dwindle and become more unstable, we need to find alternate sources of sustainable energy. One, less commonly thought of, source of renewable energy is humans. Everyday thousands of people go to exercise gyms to get rid of their unwanted energy. By adding a few pieces of hardware to the equipment that people workout on, it is possible to capture this energy and convert it into usable electricity. Benefits of an energy capture system at the Intramural and Activities Center (IMA) case study include: -alternate source of energy to fossil fuels -reduced carbon footprint of the IMA -education of gym users about renewable energy, and on their daily energy consumption -empowerment of users to have an impact on energy production Primary Functional Requirements (Needs):Secondary Functional Requirements (Wants):  capture energy expelled by human  convert energy to electricity  transmit energy back to power grid  be compatible with existing exercise equipment  be at least 70% efficient  be relatively small in size  be able to resist moderate impact  be able to withstand moderate exposure to water.  cost less to manufacture than competing products  be aesthetically appealing  be made of recycled materials  allow user to clearly see inner workings of system  provide readout of user energy output  be adaptable to various rotationally driven machines System Specifications The previous design requirements and the basic cycle outline helped guide us in designing an energy capture/conversion system that can be retrofitted to up to 46 out of the 60 elliptical trainers currently at the IMA. The new cycle with a more detailed design description is shown below in Figure 2. Figure 2: The more detailed design for the system cycle. Takes out the heat sync that is currently in the system, and replaces it with the proper components for energy conversion and a much smaller heat sync so as not to allow the system to overheat. Our design, as seen above, accomplishes all of the primary FR’s (Functional Requirements), however, we won’t know how well our system meets the secondary FR’s until we design, manufacture, and test a prototype. Energy Savings Since not all of the IMA’s elliptical trainers are in use at all times, we’ve decided to only implement our system on 20 elliptical trainers. These ellipticals will produce about 11,284KWh per year. At the current price of a KWh, this is roughly $1000 worth of energy, ALL PRODUCED FROM HUMANS!!! The full cost analysis breakdown is shown below in Table 2. Table2: The cost analysis breakdown for the case study of the IMA installed on 20 elipticals. Number of Ellipticals20 Energy produced per elliptical100 Wh Hours IMA is open/week108.5 hrs Weeks/year52 weeks Total energy produced per year11, 284 kWh References: 1. “Fossil Fuels.” Department of Energy. (27 Nov. 2010) Capturing Energy from Workout Equipment By: Human Harvester Alice Anderegg, Charisse Lewis, Sepehr Mahksous, and Shota Pearce. Designed System Bridge Rectifier Voltage Regulator DC/AC Inverter AC Volts DC Volts12V DC120 V AC 60 Hz 12 V DC to 120V AC 60hz 31 input invertor. It takes up t o 31 ellipticals. Has a 20 year warranty Can take between 12 and 24 V. Future Work Progressing from our initial proposal, the next step is to implement the system on 20 ellipticals in the IMA and test the implementation to determine the actual cost of the system. If successful, this system can be expanded to other equipment that would allow for similar retrofitted system, as well as expand research in this area. System Implementation Costs In terms of implementing our system, the major costs of the project will come from the labor it takes to retrofits the ellipticals at the IMA. Because of the cost of the parts used, we believe it is possible to keep the total cost below $ The costs for each part is shown in Table 3 below: Table 3: Individual Part Costs Because the system will save about $1000 per year in energy costs, the system will pay itself off in about 10 years. This is ideal since the most expensive part, the invertor, has a 20-year warranty, and the equipment at the IMA is maintained regularly by staff. PartsPrices Bridge Rectifier$13.00 each Voltage Regulator$2.00 each 12V DC to 120V AC Invertor$1, Figure 3: An example of how elliptical energy can be converted to electrical energy.