ENGINEERING A MICRO HYDROELECTRIC

ENGINEERING A MICRO HYDROELECTRIC

GENERATOR FOR USE IN GRAYWATER PIPES

ENGINEERING PROBLEM Clean energy has the potential to reduce carbon emissions. However, small-scale hydropower in household pipes is inefficient because existing devices are not optimal, so the potential energy of water flow inside graywater pipes is not fully utilized.

ENGINEERING GOALS The goal of this project is to engineer a micro hydroelectric generator for use in graywater pipes that is low cost, can generate low voltages of power, and does not negatively impact outlet velocity.

BACKGROUND Fossil fuels and greenhouse gases are major causes of climate change, which is negatively impacting the environment. Clean energy resources, such as hydro, solar, nuclear, and wind power, are helping to reduce carbon emissions, and have the power to eliminate the need of fossil fuels completely. Hydropower is a reliable way to obtain clean energy, depending solely on the energy of water to spin an impeller and generate electricity.

DECISION MATRIX Project Idea Generator from Bicycle Generator From Graywater Pipes App to Help with Education Cost (1 = low, 3 = high) Time (1 = low, 3 = moderate) Interest (1 = low, 3 = high) Total Score 1 1 2 4 1 3 3 7 1 3 1 5 This decision matrix was used to decide which of the 3 projects to pursue. These 3 criteria had equal weight.

PROCEDURE Computer Aided Design (CAD) will be used to design a variety of impellers. The optimum design for the impeller with be determined using a both digital Computational Fluid Dynamics (CFD) analyses and real-world testing of 3D printed models. Maximum water flow rate and maximum voltage output will be measured and used to analyze the effectiveness of the generator. The impellers impact on theoretical outlet velocity will be evaluated using CFD and used to determine the best model.

MATERIALS Tubing Ball Valve Arduino Mega 2560 Hall Effect Water Flow Sensor (1/2 ) Multimeter Mini DC Motor Adaptive Holder For Impellers (3D Printed) Impellers (3D Printed) 2 Ball Bearings

PROCESS A testing model was assembled that includes a water flow sensor, a ball valve, tubing, and the adaptive holder for the impellers. The impeller was slid into the adaptive holder through an access panel and the DC motor was adhered. The water flow sensor was attached to an Arduino Mega 2560, and the DC motor was secured to a multimeter. For each trial, the valve was shut and water was filled up to a line marked in the topmost tube. A serial monitor was opened to display flow rate. The valve was opened, and the maximum voltage produced by the system was recorded, along with the maximum flow rate.

Max Voltage (V) Max Voltage (V) RESULTS 0.30 0.25 0.20 0.15 0.10 0.05 12/03/2017 0.31 0.29 0.27 0.25 0.23 0.21 0.19 0.17 12/10/2017 0.00 40 60 80 100 120 140 160 180 Max Waterflow (ml/s) 0.15 140 145 150 155 160 165 170 Max Waterflow (ml/s) Figure 4: First Round of Preliminary Data Collection. Valve open varying amounts. Figure 5: Second Round of Preliminary Data Collection. Valve completely open.

Figure 2: Baseline Impeller Designed in Onshape Figure 3: Adaptive Impeller Holder V1 Figure 1: Image of Data Collection Set Up

Table 1: Preliminary Data Round 1 Table 2: Preliminary Data Round 2 Table 3: Round 2 Summary Table 12/3/2017 Waterflow Voltage Trial q max (ml/s) V max (V) 1 155 0.23 2 159 0.23 3 151 0.27 4 155 0.24 5 159 0.24 6 159 0.20 7 151 0.23 8 155 0.27 9 155 0.22 10 159 0.25 11 66 0.00 12 99 0.27 13 70 0.24 14 77 0.21 15 55 0.07 16 111 0.22 17 88 0.03 18 48 0.00 19 88 0.17 20 122 0.09 21 103 0.01 12/10/2017 Waterflow Voltage Trial q max (ml/s) V max (V) 1 155 0.23 2 159 0.20 3 155 0.17 4 151 0.16 5 155 0.28 6 151 0.28 7 166 0.28 8 159 0.29 9 159 0.28 10 155 0.28 11 155 0.29 12 159 0.28 13 159 0.27 14 155 0.29 15 151 0.30 16 155 0.25 17 144 0.22 18 155 0.28 19 162 0.25 20 159 0.28 12/10/2017 Waterflow Voltage Trial q max (ml/s) V max (V) Avg 156 0.26 STDEV 4.68 0.04 %RSD 3.00 16

DATA ANALYSIS In the first preliminary data collection (December 3 rd ), the ranges of the model were explored. For the first ten trials the valve was opened completely, and the data points were relatively similar to each other so they clumped together, as seen in Figure 4. When the valve was not opened fully, there were large variations in both flow rates and voltages. It was concluded that in order to have a proper baseline for comparisons, the valve should be completely opened for every trial.

In the second preliminary data collection (December 10 th ), the valve was opened completely for every trial, in order to collect higher quality baseline data. The data collected shows an average water flow rate of 156 ml per second allowed the baseline impeller model to produce an average of 0.26 volts.

DESIGN CRITERIA Low Cost Does Not Highly Impact Outlet Velocity Generates Low Voltages Of Power

FUTURE WORK To increase the voltage output of the generator, the impeller design will be modified significantly, with edits including curved blades, and more surface area covered inside the tube. Gears will also be added in order to increase the number of times the motor rotates for each turn of the impeller. To analyze effects of the impellers on output velocity, each design will be run through a Computational Fluid Dynamics (CFD) simulation is and results will be examined.

TIMELINE December: Create and print an improved, version 2 of the adaptive impeller holder. Design, print, and test different gears. Make in CAD all impeller designs and run all designs through flow simulations. January: Print and test the best designs. Choose the best design based on the criteria chosen.