- Technology and Innovation
Sizing Frigomar Chilled-Water and Self-Contained AC Systems for Offshore Cruising
Calculating the Thermal Load
Marine air conditioning systems reject absorbed heat directly into the ocean through a dedicated seawater circuit comprising a through-hull, strainer, and pump. Determining the exact cooling requirement for a vessel relies on three primary metrics rather than simple hull length: specific cabin floor area, operational climate, and the extent of structural glass. Cruising in tropical or Gulf waters generates a significantly higher thermal load than Mediterranean navigation due to elevated air and sea temperatures. Furthermore, a deck saloon wrapped in expansive windows demands far more cooling capacity than a lower cabin outfitted only with standard port lights.
Self-Contained Versus Chilled Water
Selecting the correct mechanical architecture depends entirely on the number of isolated zones requiring climate control. Frigomar manufactures self-contained units ranging from 7,000 to 24,000 BTU, which house the compressor, condenser, and evaporator in a single footprint. These platforms are highly effective for one or two adjacent zones where cooled air is ducted short distances. For larger vessels requiring three or more independent zones, a chilled-water system provides superior thermal distribution. Operating between 50,000 and 180,000 BTU, these centralized chillers pump cold water through small-bore piping to individual fan coils, ensuring cold air travels efficiently as a liquid without losing pressure.
Generator Load and Alternating Current
Traditional air conditioning units generate massive electrical spikes during startup. Frigomar resolves this specific mechanical friction through variable-capacity units that draw a maximum of 2A upon activation, entirely avoiding the 20 to 30A inrush typical of conventional systems. This heavily reduced starting current allows owners to pair the cooling architecture directly with modern Paguro or Westerbeke alternating current generators without artificially oversizing the genset simply to absorb the initial electrical surge.
Direct Current and Lithium Integration
As the marine sector shifts toward advanced energy storage, climate control must adapt to direct current architecture. Frigomar produces specific DC models engineered to run on 12V, 24V, or 48V networks, aligning perfectly with high-capacity lithium battery banks. When operating in ECO mode, the smaller frames draw just 155W, while larger units require 230W. This remarkably low power draw allows operators to maintain overnight climate control directly from the batteries without running a generator, relying on solar arrays or brief shore power connections to recharge the bank.
Variable-Capacity Operations and Heating
Maintaining a stable cabin environment requires intelligent compressor management. Rather than constantly cycling fully on and off, Frigomar variable-capacity units ramp their output to match the precise thermal demand, keeping the cabin at a steady setpoint while operating quietly. This operational protocol yields an estimated 50 percent reduction in seasonal energy consumption compared to traditional hardware. For vessels operating in colder offshore climates, these units feature reverse-cycle capability, drawing ambient heat from the seawater to warm the cabin far more efficiently than resistive heating elements. Proper installation, including condensate routing and seawater flow management, is handled by the AYS approved installer network across the UK, Channel Islands, and Gibraltar.
