PhD Defense Andrea Meroni

Design and Optimization of Turbomachinery for Thermodynamic Cycles Utilizing Low-Temperature Heat Sources

Organic Rankine cycle power systems and heat pump systems are considered as attractive technologies for the exploitation of excess heat into electricity and useful heat. However, the development of such mass-produced low-temperature thermodynamic cycles is hindered by the lack of cost-competitive solutions. In organic Rankine cycle power systems and heat pumps, the expander and the compressor are key components regarding cost and performance. In this respect, the use of reliable and accurate numerical models for these machines is currently one of the major challenges in the field.

This Ph.D. thesis investigates three turbomachinery technologies: axial and radial turbines for organic Rankine cycle power systems, and centrifugal compressors for heat pump systems. The objectives of the work are two. The first objective is to develop suitable numerical models for the preliminary design and performance prediction of such machines. The second objective is to develop and apply design optimization methodologies which allow combining the machine and the cycle designs to identify suitable solutions from the performance and technical viewpoints.

One-dimensional models were developed for the three turbomachinery technologies mentioned above, based on a review of the relevant literature in the field. The models were validated with different test cases, including working fluids used in the specific application. In the case of axial turbines and centrifugal compressors, methodologies for the combined design optimization of both the machine and the thermodynamic cycle were developed and were applied to case studies relevant in the Danish industry.

The use of the developed models and methodologies allows achieving accurate solutions for the cycle and the machines and avoids the selection of infeasible solutions from the technical and performance viewpoints. The methods and results are intended to be used as a basis for the identification and development of cost-competitive solutions for organic Rankine cycle and heat pump applications.


fre 23 nov 18
13:00 - 17:00


DTU Mekanik


DTU Lyngby Campus, Bygning 421, Auditorium 71