Ice From the Sun

Did you know you can get ice from the sun? Amazing, but absolutely true. Thanks to some incredible technology, we can now make real ice cubes on Corroboree. “Well, of course you can,” I hear you say. “Just run your refrigerator, duh!” But that’s the point—we don’t have a refrigerator, and since I am extremely technologically challenged, I have brought in an expert, aka Eric, to explain how this new magic occurs.

Arliss: First of all, thank you, Eric, for joining me, since you know how hopeless I am at this stuff.

Eric: Yes, you are, but I love you anyway.

Arliss: So to start, please explain why Corroboree doesn’t have a refrigerator.

Eric: Well, she does, but it’s a 30-year-old system that isn’t very practical. The refrigeration compartment is deep and hard to access and its cooling element runs off the engine. We’d have to run the engine for almost an hour every day to keep the food cool, and that’s noisy and consumes diesel fuel. I blame the designer for this but it was standard at the time.

Arliss: I blame him, too, but I love him anyway. So, how have you been keeping vital foods like cheese and beer cold on your boat?

Eric: We use a plastic picnic cooler with bags of ice purchased onshore. In the 95-degree heat here in Puerto Rico, a six-pound bag of ice melts within 24 hours and the cold water lasts another 24, so we need a new bag of ice every other day.

Arliss: But now we have a new piece of equipment.

Eric: Yes, we just bought a countertop ice-cube maker. It measures 9.5” x 14” x 13” and it’s essentially a mini-refrigerator that works on the principle of expanding gas to withdraw heat from the water, thus freezing it.

Arliss: Say what?

Eric: In other words, you fill the well of the ice-cube maker with water and plug in the cord. The water freezes on a double row of prongs, and the cubes—they’re actually shaped like hollow bullets—drop off the prongs and into a basket. Then another batch begins.

Arliss: How come we didn’t have one of these before?

Eric: I didn’t know they existed.

Arliss: Aren’t you an engineer? Anyway, you plug the cord of the ice maker into one of Corroboree’s electrical outlets…

Eric: …which are wired to the inverter, a large, heavy unit that’s connected to the boat’s three marine batteries. The inverter draws 12-volt DC current from the batteries and converts it to 110-volt AC current at the electrical outlets. The batteries, in turn, get their power from the two solar panels tied on top of our bimini. Each panel measures 21” x 42” and delivers 100 watts, so we have 200 watts of solar power total. That’s enough to run everything on the boat—the cabin and exterior lights, the fans, our computers and iPad, my electric tools.

Arliss: But how does a solar panel itself work? To me, it just looks like a sheet of plastic.

Eric: It is a sheet of plastic, and it contains 32 photovoltaic cells that convert sunlight to DC electrical current.

Arliss: Okay, I won’t ask you to explain how photovoltaic cells work or my brain would scramble. But if we now trace it the other way, it goes like this: The sun shines on our solar panels, which convert the sunlight to electricity and send it to our marine batteries. From the batteries, the electricity goes through the inverter to the electrical outlets. We plug the ice-cube maker into the electrical outlet and voila! Ice from the sun.

Eric: Right, but the ice-cube maker draws a lot of current, 20 amps, and it has to run for several hours to make just one pound of ice. So we’ll use it in the mornings and turn it off at noon to give the batteries a chance to be topped back up by the solar panels. On the other hand, once the ice cubes have melted, we can filter and reuse that water to make more ice cubes. So not only do we have ice from the sun, the ice cubes themselves are recyclable and we don’t deplete our water supply.

Arliss: Pretty cool!

Eric: Yes, it is. Now where’s my beer?