Oceanic Thermal Energy Conversions Group Members: Brooks Collins Kirby Little Chris Petys Craig Testa

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

Working Fluid Difficulties Our previous working fluid, ammonia (NH 3 ) is poisonous at high concentrations and is an irritant to the eyes, nose, and lungs. Our previous working fluid, ammonia (NH 3 ) is poisonous at high concentrations and is an irritant to the eyes, nose, and lungs. Possible replacements for ammonia include Propane (C 3 H 8 ), Butane (C 4 H 10 ), or R-22. Possible replacements for ammonia include Propane (C 3 H 8 ), Butane (C 4 H 10 ), or R-22. When compared to the possible replacements, ammonia is the most thermally efficient. When compared to the possible replacements, ammonia is the most thermally efficient.

Turbine Difficulties Sourcing a turbine Sourcing a turbine Finding a reasonably sized turbine is difficult due to the fact that many industrial turbines are for extremely large applications. Finding a reasonably sized turbine is difficult due to the fact that many industrial turbines are for extremely large applications. Limited manufacturers Limited manufacturers We could possibly use a reverse driven centrifugal pump as a turbine We could possibly use a reverse driven centrifugal pump as a turbine Using the turbine side of a small turbocharger is also a possibility Using the turbine side of a small turbocharger is also a possibility

Budget Difficulties Expensive design with many specialized components and a very limited budget. Expensive design with many specialized components and a very limited budget. Our contacts at Lockheed Martin have expressed their willingness to extend our budget to meet the system requirements. Our contacts at Lockheed Martin have expressed their willingness to extend our budget to meet the system requirements. Due to this budget extension we have modified our design to a more robust and effective design. Due to this budget extension we have modified our design to a more robust and 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 DesignNew 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 Schematic

Plate Heat Exchangers Alfa Laval M6 Plated Heat Exchanger Alfa Laval M6 Plated Heat Exchanger We must work with Alfa Laval to create a heat exchanger that fits our specific needs. We must work with Alfa Laval to create a heat exchanger that fits our specific needs. We can custom order number of plates and heat exchanger size to our heat requirements We can custom order number of plates and heat exchanger size to our heat requirements

Plate Heat Exchanger Fluid Flow

Calculations: Ammonia (R-717) Stage 1: Enthalpy h1h1h1h kJ/kg Pressure P1P1P1P kPa Density ρ1ρ1ρ1ρ kg/m^3 Entropy s1s1s1s kJ/(kg*K) Stage 2: Pressure P2P2P2P kPa Enthalpy h2h2h2h kJ/kg Work W PUMP.623 kJ/kg Stage 3: Enthalpy h3h3h3h kJ/kg Entropy s3s3s3s kJ/(kg*K) Stage 4: Enthalpy h4h4h4h kJ/kg Entropy s4s4s4s kJ/(kg*K) Total Cycle Heat q in kJ/kg Work W in.623 kJ/kg Heat q out kJ/kg Work W out kJ/kg Thermal Efficiency η th 1.66% Mass Flow Rate m dot kg/s

Future Fall & Spring Schedule NOV M|TU|W|TH|F DEC M|TU|W|TH|F JAN M|TU|W|TH|F FEB M|TU|W|TH|F MAR M|TU|W|TH|F APR M|TU|W|TH|F ORDER PARTS, FINAL DESIGN PACKAGE, SPRING PROPOSALS DIAGNOSE AND CORRECT PROBLEMS BEGIN OPERATIONS MANUALS OPEN HOUSE ON TIME! ASSEMBLE AND TEST EACH COMPONENT PROGRESS REPORT FINAL DESIGN REVIEW MIDPOINT REPORT BEGIN FINAL REPORT