Project 3: High Performance Recuperators for Waste Heat Recovery Cycles

Background: Enhanced energy efficiency in ship service systems can be obtained by combining the existing gas Brayton cycle with a cycle that uses turbine exhaust waste heat. Several options exist for waste heat recovery in ship systems, for either additional electric power generation or for cooling/air conditioning. Among the various options available for power generation, supercritical carbon dioxide cycles (sCO2) has gained increasing attention in recent years due to its relatively high efficiencies (~50%) at moderate source temperatures (~550 C), small size, and simple controls. Other opportunities include useCrucial to either of the above mentioned energy efficiency methods is an efficient recuperator, which extracts heat from the gas turbine exhaust and transfers it to the secondary cycle working fluid. Key attributes of the recuperator are that it is compact and presents a low backpressure in the turbine exhaust (typically less than 5 inches of water), and that is able to withstand thermal cycling.

Given the important role of the recuperator in waste heat recovery applications, it is critical that its thermofluidic performance be optimized for the desired application.

Project Goal: The goal of this project is to develop an experimentally-validated design of a compact recuperator for sCO2 power cycles. The principles used in the recuperator design could also be used in the design of low backpressure heat recovery units for use in absorption/adsorption cycles and other applications.

Project Details: The project objectives are to:

  • Establish a simplified thermal, fluidic, and mechanical model to design the recuperator
  • Validate the mechanical integrity and thermofluidic performance of a chosen design from the model output based on laboratory-scale experiments
  • Optimize the design of the recuperator based on realistic constraints of system backpressure

Lead Research Unit: UC Davis Western Cooling Efficiency Center

Principal Investigator: Dr. Vinod Narayanan

Associated Staff/Researchers: Theresa Pistochini