Tropical vs Temperate Marine Air Conditioning Sizing
The short answer
Use the warmest realistic cruising conditions in the design brief, including seawater temperature, humidity and solar load. The site’s tropical and temperate factors are planning assumptions, not manufacturer derating curves. Check the selected unit’s actual output at the intended conditions before ordering a larger capacity.
Tropical vs Temperate Boat AC Sizing — Requirements and Limitations
The condenser rejects heat to seawater. Changes in seawater temperature affect operation, but the amount depends on the equipment and conditions. Ask for rated performance at the design point rather than assuming every product loses the same percentage.
Humidity compounds it. Only a refrigeration cycle removes water from the air, which is why a fan does not substitute in the tropics no matter how big it is, and why a tropical system spends much of its capacity dehumidifying rather than cooling.
Related Sizing, Installation and Service Guides
Each of these answers a different part of the same problem.
- sizing for the tropicsthe factor, and every length worked through
- sizing for temperate waterthe same, for the south
- your own home porteight ports, each with its seawater temperature
- compare the three climatesthe curve, and where they diverge