Oceanic Thermal Energy Oceanic Thermal Energy ConversionsConversions

Group Members:Group Members:Brooks CollinsBrooks Collins

Kirby LittleKirby LittleChris PetysChris PetysCraig TestaCraig Testa

Problem Statement of ProjectProblem Statement of Project

• To create and design an operating To create and design an operating Oceanic Thermal Energy Conversion Oceanic Thermal Energy Conversion model that employs a closed Rankine model that employs a closed Rankine Cycle that utilizes ammonia or a Cycle that utilizes ammonia or a comparable refrigerant as the working fluid comparable refrigerant as the working fluid to illustrate the viability of OTEC power to illustrate the viability of OTEC power production.production.

Working Fluid DifficultiesWorking Fluid Difficulties

Our previous working fluid, ammonia (NHOur previous working fluid, ammonia (NH33) ) is poisonous at high concentrations and is is poisonous at high concentrations and is an irritant to the eyes, nose, and lungs.an irritant to the eyes, nose, and lungs.

Possible replacements for ammonia Possible replacements for ammonia include Propane (Cinclude Propane (C33HH88), Butane (C), Butane (C44HH1010), or ), or R-22.R-22.

When compared to the possible When compared to the possible replacements, ammonia is the most replacements, ammonia is the most thermally efficient.thermally efficient.

Turbine DifficultiesTurbine Difficulties

Sourcing a turbineSourcing a turbineFinding a reasonably sized turbine is difficult Finding a reasonably sized turbine is difficult

due to the fact that many industrial turbines due to the fact that many industrial turbines are for extremely large applications.are for extremely large applications.

Limited manufacturersLimited manufacturersWe could possibly use a reverse driven We could possibly use a reverse driven

centrifugal pump as a turbinecentrifugal pump as a turbineUsing the turbine side of a small turbocharger Using the turbine side of a small turbocharger

is also a possibilityis also a possibility

Budget DifficultiesBudget Difficulties

Expensive design with many specialized Expensive design with many specialized components and a very limited budget.components and a very limited budget.

Our contacts at Lockheed Martin have Our contacts at Lockheed Martin have expressed their willingness to extend our expressed their willingness to extend our budget to meet the system requirements.budget to meet the system requirements.

Due to this budget extension we have Due to this budget extension we have modified our design to a more robust and modified our design to a more robust and effective design. effective design.

Requires

• 1 pump• 2 heat exchangers• 2 water tanks cold/hot• 1 turbine• 1 generator

Benefits

• less pumps• less tubing• cheaper

Requires

• 3 pumps• 2 plate heat exchangers• 2 water tanks cold/hot• 1 turbine• 1 generator

Benefits

• much more advanced heat exchangers • will provide forced conduction• will provide more constant temperatures

Previous Design New Design

Working fluid is pumped into evaporator

Evaporator is placed in a heated tank to vaporize the working fluid

Vapor turns turbine and power is produced with a generator

Condenser is placed in a cold tank to cool vapor back into liquid

Cycle begins again

Previous Design

Working fluid is pumped into evaporator

Vapor turns turbine and power is produced with a generator

Condenser cools vapor into liquid using water from a cold tank pumped through it (forced conduction)

Cycle begins again

Evaporator turns the working fluid into vapor using water from a heated tank that is pumped through it (forced conduction)

New Design

New Design SchematicNew Design Schematic

Plate Heat Exchangers

Alfa Laval M6 Plated Alfa Laval M6 Plated Heat ExchangerHeat Exchanger

We must work with Alfa We must work with Alfa Laval to create a heat Laval to create a heat exchanger that fits our exchanger that fits our specific needs.specific needs.

We can custom order We can custom order number of plates and number of plates and heat exchanger size to heat exchanger size to our heat requirementsour heat requirements

Plate Heat Exchanger Fluid Flow

Calculations: Calculations: Ammonia (R-717)Ammonia (R-717)

Stage 1:Stage 1:      

EnthalpyEnthalpy hh11 18.912 kJ/kg18.912 kJ/kg

PressurePressure PP11 429.819 kPa429.819 kPa

DensityDensity ρρ11 638.56 kg/m^3638.56 kg/m^3

EntropyEntropy ss11 0.712 kJ/(kg*K)0.712 kJ/(kg*K)

Stage 2:Stage 2:      

PressurePressure PP22 827.37 kPa827.37 kPa

EnthalpyEnthalpy hh22 181.533 kJ/kg181.533 kJ/kg

WorkWork WWPUMPPUMP .623 kJ/kg.623 kJ/kgStage 3:Stage 3:      

EnthalpyEnthalpy hh33 1465.025 kJ/kg1465.025 kJ/kg

EntropyEntropy ss33 5.065 kJ/(kg*K)5.065 kJ/(kg*K)

Stage 4:Stage 4:      

EnthalpyEnthalpy hh44 1443.668 kJ/kg1443.668 kJ/kg

EntropyEntropy ss44 5.337 kJ/(kg*K)5.337 kJ/(kg*K)

TotalTotal Cycle Cycle HeatHeat qqinin 1283.49 kJ/kg1283.49 kJ/kg

Work Work WWinin .623 kJ/kg.623 kJ/kg

HeatHeat qqoutout 1262.756 kJ/kg1262.756 kJ/kg

Work Work WWoutout 21.357 kJ/kg21.357 kJ/kg

Thermal EfficiencyThermal Efficiency ηηthth 1.66%1.66%

Mass Flow Rate Mass Flow Rate mmdotdot .00468 kg/s.00468 kg/s

Future Fall & Spring ScheduleFuture Fall & Spring Schedule

NOVM|TU|W|TH|F

DECM|TU|W|TH|F

JANM|TU|W|TH|F

FEBM|TU|W|TH|F

MARM|TU|W|TH|F

APRM|TU|W|TH|F

ORDER PARTS, FINAL DESIGN PACKAGE, SPRING PROPOSALS

DIAGNOSE AND CORRECT PROBLEMS

BEGIN OPERATIONS MANUALS

OPEN HOUSEON TIME!

ASSEMBLE AND TEST EACH COMPONENT

PROGRESS REPORT

FINAL DESIGN REVIEW

MIDPOINT REPORT

BEGIN FINAL REPORT