PTBU v1.0: Polar Thermal Breakwater Unit
Year: 2026
Type: preprint
Abstract: The Polar Thermal Breakwater Unit (PTBU) is a hybrid coastal-protection concept that combines mechanical coastal protection with a sealed internal freshwater or low-salinity water core intended to undergo seasonal freezing and melting. The external form follows the logic of interlocking concrete armor units used in breakwaters, while the internal cavity provides a passive phase-change thermal function. The base configuration requires no continuous electrical power, pumps, moving valves, thermosyphon systems, or heat-pipe devices. The mechanical function is intended to address waves, currents, ice movement, uplift, overturning, and displacement through self-weight, inter-unit interlocking, and seabed interaction. The thermal function is treated separately and conservatively: the concept asks whether seasonal freezing and melting of the sealed core can produce a measurable local modification of heat flux, local ice conditions, or melt behavior relative to an appropriate control. The paper develops the concept using sensible heat transfer, latent heat of fusion, transient conduction through the concrete shell, seasonal thermal forcing, expansion allowance during freezing, hydrodynamic stability requirements, environmental constraints, measurable success indicators, staged testing, and explicit failure criteria. A first simplified transient calculation is reported using an effective water volume of 80 m³, a baseline concrete wall thickness of 0.45 m, concrete thermal conductivity of 1.6 W·m⁻¹·K⁻¹, an effective heat-transfer area of 95 m², and simplified polar seasonal forcing. Under the stated lumped-model assumptions, all tested sensitivity cases reach full freezing and return to full freezing by the end of the annual cycle. These results are explicitly treated as preliminary and optimistic because the model does not yet resolve the progressive growth of the internal ice layer as a moving thermal boundary. A Stefan-type moving-boundary formulation is identified as the next required thermal validation step, together with structural, hydrodynamic, laboratory, wave-basin, and staged field testing. The PTBU concept is presented as a falsifiable engineering hypothesis rather than as a demonstrated technology.
Author: Alhawarat M, Ali
Language: English
Topic: Coastal and Marine Dynamics
Subfield: Earth-Surface Processes
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214516949
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