Session: 09-01 Industrial Process Heat and Waste Heat

Paper Number: 114938

114938 - Comparison Between Organic Rankine Vapor Compression Configurations With Variable Operating Conditions 

Marine ships rely on large diesel engines, which are typically less than 50% efficient, for propulsion and auxiliary power generation. Waste heat recovery technologies have the potential to reduce fuel consumption and address increased electricity and cooling demands in shipboard applications. However, engine loads and cooling water temperatures are highly variable which makes relying on waste heat recovery technologies difficult. This study investigated the use of an organic Rankine vapor compression (ORVC) cooling system variant, termed the turbo-compression cooling system (TCCS), to provide comfort cooling on a large ship using low-grade waste heat in the engine’s jacket water and lubrication oil. Five working fluids were selected based on safety, environmental, and performance characteristics: R134a, R1234ze(E), R1234yf, R245fa, and R515a. Each fluid was thermodynamically modeled in three different system configurations over a range of waste heat and ambient conditions: using the TCCS to provide thermally driven supplemental cooling, pre-cooling seawater to improve the performance of an electric chiller, and providing a continuous cooling duty using a hybrid electrically and thermally driven system. Despite having lower thermally driven performance, the electrically boosted TCCS had higher annual fuel savings than a single-effect absorption chiller (81.8 mt yr^-1 vs. 70.5 mt yr^-1),  cost significantly less ($372,324 vs. $741,445) and had a lower simple payback period (5.90 years vs. 13.5 years). In addition, electrically boosting the TCCS enables continuous cooling to be provided with a single system and removes redundant cooling equipment required with alternative thermally driven cooling systems.

Presenting Author: Ben Platt Colorado State University

Presenting Author Biography: Ben Platt completed his B.S. at Colorado State University (2020) and is expected to complete his Ph.D. at Colorado State University in 2024. His dissertation research focuses on waste heat recovery technologies and industrial decarbonization. He is actively working on the development of a novel waste heat driven cooling technology and is working to integrate it into the next generation of resilient and sustainable energy systems.