A boat is heading out onto the open water. Nestled in the passenger cabin, a marine air conditioning system is hissing gently. It’s discharging cool, refreshing air. How does it work? Everyone knows standard air conditioners are high load appliances. How is this compact piece of equipment keeping everything cool? Maybe there’s more to the device than meets the eye. Maybe this essential cabin cooler is operating on batteries.

Self-Contained Marine AC Units 

The key to happy cooling is to streamline the equipment, to incorporate only the bare essentials. Reduced in size and assembled as an extremely compact equipment package, the materials used here are lighter than average. The unit then slots into place within a reserved enclosure, with the lightweight form factor ensuring the hull’s balance isn’t compromised in any way. Tough though this design process obviously is, there are many examples of the principle in use, even on smaller boats. They fuse the drain pan into the design, employ low-noise moving parts, and add a much-desired water cooling feature to the equipment build.

Utilising Water-Cooled Architectures 

Here’s the biggest difference, the reason that smaller marine air conditioners can match their land-based peers. Back on land, that chemically-loaded unit uses air as a cooling medium. When the heat exchanging process reaches the condenser coil, it is air that passes over those hot coils. What if there was an alternative cooling medium? A boat, cruising over the waves, is sailing on top of millions of tonnes of cool water, which is why water-cooled appliances are a logical development. Raw or filtered, the water cools the condensers. Furthermore, the evaporator stage is equipped with a larger surface area than normal. Equipped with aluminium fins and copper tubes that are coated with a layer of protective polyester enamel, the heat exchanging process is greatly augmented. And, thanks to this water-cooling feature, the cooling power can come straight from the boat batteries. That’s 12-Volts of D.C. output, with a 30-Amp discharge. Granted, we’re talking about a 3000 to 4000 BTU cooling feature, but that’s more than enough for a small boat.

Larger ships are equipped with generators. These generators the power split-system air conditioners and ducts the cold air through several carefully concealed vents. Smaller boats don’t have that option. On those powerboats and sailing craft, a small cabin stands between the harsh midday sun and a nasty sunburn. Thankfully, inside the cabin, a self-contained marine air conditioning system is hard at work. It’s small, water-cooled, and cased in lightweight aluminium. It’s exactly what’s needed to bring comfort to that cabin cruiser.