Solar Powered Pumping for Irrigation in

St. Kitts

Charles DauphineeHiltz Tanner

Michael CooksonStephen Cookson

Mechanical Engineering Department Dalhousie University

Design Group: Charles DauphineeHiltz TannerMichael CooksonStephen Cookson

Supervisors: Dr. Peter AllenDepartment of Mechanical EngineeringDr. Jack BurneyDepartment of Biological Engineering

Client: Dr. Vincent Audain Honorary Consul of St. KittsDepartment of Medicine

SolaVive Team

Design Problem

Irrigation• 2 Acres of fertile soil

(sandy loam)• Horticultural Crop

– Requiring: 35mm/week

• Existing tank : 85ft x 1000ft from 117358USG reservoir

• Social cost of present solution

Mission

• Solar powered machinery is ideal for agriculture in developing countries

• Rural communities far from power grids• Solar flux availability• Need for ecologically sustainable technologies• Design Criteria

– simple assembly / maintenance– ruggedness– transportability– efficiency

Impact on St. Kitts

• Expands minimal existing irrigation

• Lengthens growing season• Creates year-round

employment• Lowers price of produce• Crop export possibilities• Solar versus gas and grid

0100,000200,000300,000400,000500,000

Total Yield(lbs)

Net Return($)

Net Return and Yield for 2 Acres

Without

With SolaVive

Comparitive Feasibility Study

$20,000

$30,000

$40,000

$50,000

$60,000

0 5 10 15 20

Year

Cost

Solar

Deisel

Grid

Integrated System

• Subsurface Drip Irrigation• 4500 Gallon Water Storage

Tank• P-D Dankoff Solar Pumps

• Linear Current Booster• 1.44 kW Photovoltaic Array• Existing Open Reservoir

Component Choices

Irrigation• Subsurface Drip Irrigation

– Distribution efficiency

Pump-Motor• P-D Sliding Vane Pumps in

parallel– 15.8 USgpm @ 113 ft

• 12 volt PM DC motor– high efficiency at integral

hp

Component Choices

Photovoltaics• Architecture for Reliability• LCB for Maximum Power• RETScreen Analysis: 1.7kW

Installation & Maintenance

• Installation Manual– Connecting PV Modules– Pump inlet/outlet setup

• Maintenance Manual– General Maintenance– Preventative Maintenance– Troubleshooting– PV array– Pump & Motor– Irrigation System

Numerical Analysis

• Cybernet Simulations– Create nodes on irrigation CAD drawing– Pressures in junctions, pipes, valves

• As a tool for: – Design

• Change diameter of tubing, Height of reservoir

– Testing• Numerical Model

Sponsorship & Assembly

• Project Cost: $32K

• Testing Methods– Scaled Model– Numerical Analysis

• System Assembly– Challenges– Reynolds No– Modularity: Fittings,

Wires, Valves

Testing

• Day 1– Partially Cloudy– Not enough pressure head

• Expected flux, delivery

• Actual flux, delivery

• Efficiencies

Ht 11.0 MJ/m2

Vol H2O 3037 USG

Ht 16.6 MJ /m2

Vol H2O 1359 USG

PV 8%DC-DC 88%P-M 18%

Testing

• Day 2– Sunny and appropriate head

• Expected flux, delivery

• Actual flux, delivery

• Efficiencies

Ht 26.0 MJ/m2

Vol H2O 3986 USG

Ht 24.0 MJ/m2

Vol H2O 1556 USG

PV 8%DC-DC 93%P-M 29%

Interpreting Results

• Efficiencies Predicted Actual Average

PV 11%DC-DC 92%P-M 42%

PV Efficiency vs Voltage

0.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

14.00%

14.0 15.0 16.0 17.0 18.0 19.0

Voltage (V)

Eff

icie

nc

y (

%)

PV 8%DC-DC 93%P-M 29%

Testing Conclusions

• Importance of proper component sizing

• Supply chain management• Data acquisition system• Modularity is key• Intuitive understanding

Future of SolaVive

• More Testing• Implementation• Engineers in Development• Other Alternative Energy Projects

Thanks To:Dr. CaleyMech DeptAPENSAlumni AssociationCBCL Ltd Thermodynaics LtdDr. HamdullahperDr. Jerome ThomasFidel O’FlahartyDr. Linnell EdwardsGene Knight

Questions?