Novel ORC technology offers efficiency savings
A group of researchers have proposed a novel auxiliary trigeneration waste heat recovery system that produces electricity, cooling, and freshwater. The system is expected to improve engine efficiency by around 11% under optimal conditions.
The system consists of a regenerative organic Rankine cycle with R600 working fluid, a lithium-bromide/water single-effect absorption chiller, and a humidification dehumidification desalination unit.
The researchers, from China, Iran, Saudi Arabia, Egypt, Turkey, Taiwan, Malaysia and Thailand conducted energy, exergy, and exergoeconomic analysis of the design. The temperature drop associated with the transfer of the waste heat from the engine to the generator is used as a heat source for desalination. The exhaust of the ORC turbine is used as a single-effect absorption chiller.
Under optimal conditions it produced 783.9kW of power, 949.8kW of cooling, and 98.1 m3/day of freshwater. Overall, the system improved engine efficiency by 11.3% at a total cost per unit of exergy of 0.1494 $/kWh.
The study is available here.