Waste Heat Recovery

PROJECTED CMMC LEVEL REQUIREMENT
Level 2 (Self)
TECHNOLOGY AREAS
None
MODERNIZATION PRIORITIES
Sustainment & Logistics
KEYWORDS
Energy Recovery; Fuel Efficiency; Heat Recovery; Gas Turbine Generators; Electricity; LM 2500 Turbine Engine
OBJECTIVE
Develop a low-cost waste heat recovery system capable of converting the heat energy within DDG 51 main engine exhaust into electrical power.
DESCRIPTION
LM 2500 gas turbine engines' maximum thermal efficiency is approximately 38%. This means at least 62% of the energy in every drop of fuel consumed by the process of propelling a DDG 51 Class ship is unused and available for harvesting as it is being expelled in the form of heat via engine exhaust. Significant energy that is currently wasted could be recovered from exhaust to save on fuel costs and increase the range of surface combatants. To effectively utilize all resources, the Navy seeks to capture this waste heat as usable energy source.
In the past, the Navy recovered this heat energy via the Rankin cycle to heat galley appliances with steam. However, there has never been a durable, effective, weight- and space-economizing system that utilizes waste heat to produce electrical power on a Navy ship. Within the context of enhancing the environmental record of the Navy, this initiative would productively tap an alternative energy source to reduce fuel consumption and subsequent emissions.
The Navy seeks a solution that provides an innovative system for waste heat collection and utilization that maximizes capture and use of thermal energy while minimizing impacts on any other ship system or prominent feature (especially the main engines). Also important to the Navy is an emphasis on moderating use of or impacts to the ship's profile and/or Radar Cross Section, available onboard space, and any serious impacts to weight and stability characteristics. Keeping these difficult limitations in mind, it is the Navy's goal to produce the greatest possible amount of electrical power from harvesting the abundant thermal energy from every ship's main engine exhaust. While the DDG 51 Class Gas Turbine Generators (GTGs) also have similar thermal efficiencies and the scope of this STTR topic may become inclusive of GTGs in the future, the immediate focus of the topic is on the waste heat from the LM 2500 main engines.
The proposer should quantify the level of stress the material can incur while in an operational environment, and provide a preliminary concept design and validation plan and an in-depth examination in scalability and the potential for miniaturizing any technologies highlighted within the feasibility study, as these proposed technologies will need to create a system able to fit and effectively/safely operate within the DDG 51 Class footprint(s) and meet weight and stability requirements.
PHASE I
Develop a concept for waste heat recovery of the LM 2500 engine that accomplishes the requirements listed in the Description. Demonstrate the feasibility of the concept with a development plan and proposed test plan that will include testing to failure and compliance with environmental standards. Accompany the feasibility study with a recommendation of how the technology could be best incorporated into DDG 51 Class ships. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II. Prepare a Phase II plan.
PHASE II
Develop and deliver a prototype and/or a comparable simulation able to demonstrate the conformance with power-generation industry standards and according to actual operating specifications, conditions, and DDG 51 Class footprints. A high-fidelity industry-standard computerized predictive model/simulation of the system displaying all significant data points of the system while in operation is needed and/or a high-fidelity (to no less than 1/32 scale) working prototype of the system. The simulation must validate the functionality/effectiveness of the system. A comprehensive installation plan, itemizing any required materials and their sources, recommending the safest and most cost and time-effective installation techniques will also accompany all Phase II documentation as a deliverable. Conduct a thorough examination and estimate of potential electrical output across the range of ship speeds and engine conditions to include idle.
PHASE III DUAL USE APPLICATIONS
Support the Navy in transitioning the technology to Navy use. The product will be validated, tested, qualified, and certified for Navy use.
There are any number of industries that utilize gas turbines, and this technology will likely be applicable to many of those industries where abundant spare electrical power can and would be fully utilized.
REFERENCES
Reddy, Chirla Chandra Sekhara and Rangaiah, Gade Pandu. "Waste Heat Recovery: Principles and Industrial Applications." National University of Sinapore, Singapore, June 2022, ISBN: 978-981-12-4839-9. https://www.worldscientific.com/worldscibooks/10.1142/12588?srsltid=AfmBOophN-SvmkZUVPtqBBxYi_aHBE32uuWedRz8Sdy0omI94usKlHan#t=aboutBook
Borge-Diez, David and Rosales-Asensio, Enrique. "Heat Energy Recovery for Industrial Processes and Wastes." Green Energy and Technology Book Series, 2023. https://link.springer.com/book/10.1007/978-3-031-24374-5
Srinivas, Tangellapalli. "Thermal Cycles of Heat Recovery Power Plants." Bentham Science Publishers, March 31, 2021, ISBN 9789811803765. https://benthambooks.com/ebook-files/sample-files/9789811803772-sample.pdf
Reina, Denzel. "Waste Heat Recovery Analysis Of A Gas Turbine Heat Exchanger." Naval Postgraduate School Monterey, California Thesis, March 2021. https://apps.dtic.mil/sti/trecms/pdf/AD1150770.pdf