Catalina 30 TRBS #2889 "Northern Light"

Isotherm Compact Model G150 refrigerator/icebox

The rest of the modifications.

The Isotherm Compact Model G150 (installed April 2017) can be a freezer or refrigerator. We decided, as with the previous Adler Barbour Cold Machine installation, to make it a freezer. With an insulated barrier between freezer space and refrigerator space, "spill over" air flow from the freezer compartment is what cools the refrigerator compartment.

This is the evaporator plate as shipped. It barely fits into the aft wall of the icebox compartment.

The evaporator plate is bendable (within limits). The lower right corner was angled to fit and was secured to the aft wall using nylon standoffs. Aluminum angle brackets were screwed into the sides and bottom of the icebox compartment to secure an insulating barrier in place.

An insulating barrier was fabricated with two-inch styrofoam. The process included making a cardboard template due to the complex curves and shape. The styrofoam was then wrapped in shrink wrap material from the boat yard and taped in place.

A top and hinged lid was fabricated from ABS plastic and lined on top and bottom with aluminized "bubble wrap" insulation held with contact cement. A two-inch hole was bored through the insulation near the bottom for the "spill over" air flow from the freezer compartment. There is enough leakage at the top to allow thermal convection to occur.

The compressor was mounted high in the port aft locker to keep it out of the way of the stuff that normally kicks around in an outside boat locker. I used the convenient Isotherm mounting bracket with two pieces of 1/4" aluminum strap to engage the screws coming through the underside of the deck track. Self-tapping screws at the bottom are drilled into the fiberglass liner.

The compressor/condensor/controller assembly drops onto the mounting bracket and is plumbed to the evaporator in the the icebox compartment. Quick disconnect fittings make installation easy.


You can see in the photos that this installation is not very refined and certainly not as nice looking as other custom icebox installations that are out there. The reason is this: We have limited solar power. It was sufficient for the previous Adler Barbour Cold Machine. Although it claims to be more efficient the Isotherm unit is new to us and we don't know how it will function in our particular freezer/refrigerator cubic footage. Using styrofoam, shrink wrap, and bubble wrap gives us the ability to experiment, find out what we need, and prototype it before committing time and energy to make it permanent.

I anticipate that a fan will be needed to circulate air between freezer and refrigerator. I also anticipate that I'll need to provide some airflow in the port aft locker so that the compressor gets properly cooled.