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Design Priorities

Cost was prioritized over efficiency of the system. An increase of 83% to 84% efficiency resulted in a cost increase of $5,807.86 (determined to be reasonable) whereas an increase of 84% to 85% efficiency resulted in a cost increase of $58,516.04 (deemed unreasonable via decision matrix). Success was defined by creating a hydro-storage system under $500,000 with an efficiency over 75% (as outlined by team-generated engineering specifications), both of which were met by the optimized model.

Design Approach

A combination of decision matrices, engineering specifications, and test cases led to the determination of parts for optimal design. The zone choice was a major decision for optimizing the model as it determined numerous values that could not be changed. This zone was chosen for its minimal risk, cost, and high potential energy generation. Determining to value cost over efficiency related to the breakdown of price increase per 1% increase in efficiency as shown in test cases. The model’s ability to meet engneering specifications considered in all stages.

Design Illustration

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Model Description

Hardcored:

Height: 30 m

Bends & Bend Angles: 2 bends at 30 degrees each

Length of Pipe: ~67 m

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Most Efficient Inputs:

Pump Efficiency: 0.92

Turbine Efficiency: 0.94

Pipe Diameter: 3 m

Pipe Friction Factor: 0.002

Reservoir Depth: 5 m

Volumetric Flow Rate of Pump:

40 m^3/s

Volumetric Flow Rate of Turbine:

40 m^3/s

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Results

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Ratio of Total Cost/System Efficiency: $18,570.18/% Efficiency

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Summary of Design Function

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Description of Other Factors

Other factors besides cost and efficiency mostly came to attention when choosing the zone in which to build the reservoir. Risk encompasses environmental and cultural impact. The short and long term erosion concerns of Zone 3 and the potential cultural apathy of using Zone 2 lead to avoidance of those two zones, leaving Zone 1 for the building site.

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Acknowledgements

Team 49 would like to thank Seymour Crystals Incorporated for the opportunity to work with them on this design. They would also like to thank the ENGR 142 instructional team for their guidance, as well as the administrators of the engineering toolbox website for their clear explanation of relevant equations. FInally, we would like to acknowledge Purdue University.

Determining Optimal Efficiency and Cost of Hydro-Storage System

Adrienne Farr, Nicholas Finan, Dana Wang, Julia White

Purdue University Honors Engineering