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Team Members: Ben Steffes Dan Neumann Brandon Jackson Nate Weber Chris Chapman Faculty Advisor: Dr. Chris Damm. Design and Modeling of Combined Heat and Power Systems for Sustainable Urban Agriculture and Aquaculture.
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Team Members: Ben Steffes Dan Neumann Brandon Jackson Nate Weber Chris Chapman Faculty Advisor:Dr. Chris Damm Design and Modeling of Combined Heat and Power Systems for Sustainable Urban Agriculture and Aquaculture Collaboration for aquaponicssustainableEnergy Milwaukee School of Engineering
Aquaponics overview Borrowed from: http://www.photosbysc.com/Aquaponics/Saras_Aquaponic_Blog/Entries/2008/4/13_What_is_Aquaponics_files/droppedImage_1.png
CHP overview • CHP Combined Heat and Power • One fuel source for multiple types of output power • Electricity • Thermal Energy • High overall efficiency CHP System Thermal Fuel Electrical
Our Goals… • Develop models to guide in the development of an advanced energy system for aquaponics • System level design of an environmentally responsible and economical system capable of reducing carbon emissions through higher efficiency • Create a simulation tool to aid in the designing and selection of aquaponics energy systems
Greenhouse Environment between 45-60% relative humidity and 55°F-85°F Rearing Tank sizes ranging from 1,000-20,000 gallons Maintain Tank Temperature Between 75°F-85°F Consider both natural and artificial lighting Design Constraints: Aquaponics
Provide power to aerate, heat, and pump tank water Provide power for artificial lighting Operate on Natural Gas Continuous Operation With Exception for Maintenance Less CO2 emissions than Milwaukee Emission Statistic Lowest Cost/Least Environmental Impact Design Constraints: Power Production
Mechanical • Natural Gas Engine with Heat Exchangers • Supply mechanical demand for: • Pumps • Blowers • Heat exchangers to Provide heat for aquaponics tank(s) • Electrical • Commercial CHP generator set • Supply electricity for: • Pumps • Lighting • Provide heat for aquaponics tank(s) Initial Plans
Engine Trouble • Introducing lubrication (2-stroke) • Maintenance cycle • Space requirements • Efficiency of Heat Exchangers Electrical vs. Mechanical
Took system level approach to pairing CHP and aquaponics using commercially available CHP generators Selected Marathon ecopower Moving Forward with Electrical System Borrowed from: mathonengine.com
Marathon Ecopower • Estimated installed system cost approximately $35,000 • 4000 hour maintenance interval
CHP system sized for thermal load • Point of most efficient operation • Model used to approximate thermal loading • Surface convection and evaporation, wall convection, base conduction, and hydroponic tank losses Thermal Modeling
Evaporation (Two Models) • (R.V. Dunkle 1961) Based on model of distillation pond evaporation • (W.S. Carrier 1918) Empirical model based on indoor swimming pools • Surface Convection • Related to surface evaporation (I.S. Bowen 1926)
Wall Convection • Based on non-dimensionalized analysis of flat plate convection • Hydroponics Tank Losses
University of Virgin Islands (UVI) • Raft Style Commercial System • Proportioning Hydroponic Tank to Rearing Tank • Hydraulic Loading Rate • Retention Time • Feed Rate Aquaponic System Proportioning
Power Requirements • Pumping • Centrifugal Pump • 45% Efficiency (elec.-water) • Rearing Tank Aeration • Greater Stocking Density • Regenerative Blower • 64% Efficiency (elec.-water) • Artificial Lighting • Implemented in few cases • 18 Hr daylight grow period • Faster Plant Growth
Sized System For Marathon EcoPOWER (11000 gallon) University of Virgin Islands System Using developed procedure (8240 Gallon) System Calculated Power: Pumping: 0.64 Hp (460 W) Aeration: 1.44 Hp (1.06 kW) Lighting: 43.8 Hp (32.7 kW) Thermal: 39000 Btu/hr (11.43 kW) Calculated Power: Pumping: 0.50 Hp (370 W) Aeration: 1.1 Hp (800 W) Lighting: None Thermal: None UVI System: Pumping: 0.50 Hp Fish Tank Aeration: 1.5 Hp System Heat & Power Requirements
Results of economic analysis Conditions: • $35,000 installed system cost • Analysis uses current utility pricing • CHP system run using thermal load following • Net metering 1:1 • Replaces 75% efficient natural gas water heater Results: • 31,000 kWh Electricity Generated Annually • 83,000 kWh Water Heating • Using 462,000 cu.ft natural gas ($4,300) • $3,000 Annual Benefit • 12 year simple payback • 10 year payback with 3% inflation • No incentives applied
Results of Environmental Analysis Results: • 16.4 tCO2 avoided annually based on Milwaukee emissions profile • 14.5 tCO2 avoided annually based on National emissions profile • Equivalent to approximately 2.8 cars and light trucks not used • 20.4 MPG • 11,720 Miles
Future Plans • To provide a selection tool to farmers to assist in incorporating CHP into efficient aquaponics operations