Use of variable frequency drive technology in ships - Applications

Paisios, Martinos; Παΐσιος, Μαρτίνος

Master Thesis

Author

Paisios, Martinos

Παΐσιος, Μαρτίνος

Date

2025-11-20

Abstract

This thesis research examines the technical, operational and economic feasibility of the installation of Variable Frequency Drive (VFD) units on the ballast pumps of a Supramax bulk carrier. The paper focuses on the inefficiencies of traditional throttling-based pump control and the promise of VFD retrofits, with regards to energy savings, fuel saving, and greenhouse gas emissions. The study integrated pump performance modeling and the use of affinity laws together to lead to a comparative study of throttling and VFD control in various flow regimes. The results show that at partial loadings, energy savings of 50-70 percent are possible, which means that for typical ballast water throughput, savings of 10- 50 tonnes of CO2 can be achieved annually. The economic feasibility analysis revealed that although the investment is not attractive for vessels with low ballast demand and low fuel prices the investment is attractive under medium- to high- utilisation scenarios with payback periods of two to six years and strongly positive NPV horizons of 10 years. In addition to measurable savings, VFD integration also provides qualitative advantages such as smoother operation, reduced mechanical wear, longer pump life, and greater compliance with the new environmental regulations, such as the Energy Efficiency Existing Ship Index (EEXI) and Carbon Intensity Indicator (CII). In conclusion, the study shows that the VFD retrofits on ballast pumps are a viable and scalable energy efficiency measure, capable of reducing emissions and improving the sustainability profile of bulk carriers. The results not only provide technical justification, but also several economic reasons to favor the wider use of VFD technology in the maritime industry.

Postgraduate Studies Programme

ΔΠΜΣ στη Διοίκηση στη Ναυτική Επιστήμη και Τεχνολογία

Department

Σχολή Ναυτιλίας και Βιομηχανίας. Τμήμα Ναυτιλιακών Σπουδών

Corporate Department

Σχολή Ναυτικών Δοκίμων

Number of pages

Language

English

URI

https://dione.lib.unipi.gr/xmlui/handle/unipi/18715

Collections

Τμήμα Ναυτιλιακών Σπουδών

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Except where otherwise noted, this item's license is described as
Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα