Wednesday, February 10, 2016

We Have Refrigeration! -- Installing our Frigoboat Keel Cooled System

The older AC/DC Norcold refrigerator/freezer that came with Phoenix gave up the ghost when Bill motored Phoenix home from Detroit several years ago. Since then we've been relying on well insulated coolers with frozen jugs and/or block ice to keep our food and beverages cold while sailing. This was fine for 5-7 day trips on the Bay, but after that the search for marinas or grocery stores with block ice was a bit of a pain. As part of our galley redesign, it was time to finish our custom refrigerator box, install the Frigoboat refrigerator system, and say goodbye to the ice chests under the salon table.

We kept both of the doors and the framing from our old Norcold refrigerator/freezer so that we could re-purpose them with our new boxes.
Our old Norcold refrigerator/freezer that came with Phoenix

The plan was to have an under-the-counter refrigerator using the old refrigerator door, and we'll use the freezer door for the freezer box that will come later. Bill designed a 6 cubic foot stainless box to fit in the galley, and our friend/local metal fabricator made it to spec.

My Dad and Uncle David helped build the lower cabinet that houses the refrigerator during one of their visits, which we then faced with teak ply. Next, it was time for the insulation. We toyed with purchasing vacuum insulation panels (VIPs) in order to maximize the amount of insulation around the box, but we've heard from many people who were disappointed in their performance, and it seems that many of their R-values are overstated. Plus, they're expensive. We didn't want to invest a ton of money into VIPs only to be disappointed with them down the road, and we had enough room for 3+ inches of foam, so we opted for R5 polystyrene foam boards that are readily available at local hardware stores. Bill cut the panels to size, then staggered and sealed all of the seams so that the box was well insulated.
Polystyrene foam in our new refrigerator box housing

Once the foam was in place, we slid in the stainless steel refrigerator box.
Stainless steel refrigerator box in place, just starting to remove the protective film from the metal
We purchased a Frigoboat Keel Cooled K50 system for the refrigeration. If you're not familiar with the keel coolers, they are similar to water cooled systems, but instead of pumping water into and out of the boat, the refrigerant is pumped outside the boat to a heat exchanging plate mounted on the keel (or well under the waterline). It's a completely closed system, and the only moving part is the Danfoss compressor. The heat exchange is very efficient, the system is extremely quiet, and best of all, it does not blow warm air into the cabin like air cooled systems.
Frigoboat Keel Cooled System
The downside, of course, is that you have to haul the boat in order to install the keel cooler. This was done when we pulled the boat for new bottom paint and installed our Max-prop feathering propeller.

The evaporator plate was bent to fit our box dimensions at the factory before it was shipped to us, so with the box and keel cooler in place, it was time to mount the evaporator plate. Bill mounted it to the upper portion of the box, and drilled a hole through the side of the box for the copper tube to fit through (this hole was later filled with insulation around the copper tubing).

With such a large box, we had to figure out how to mount shelves to maximize our usable space. We purchased aluminum L brackets from our local hardware store, and riveted them to the sides of the box to hold the shelves in place.
Refrigerator box with evaporator plate and lower shelf supports installed

We opted to mount the temperature control module (thermostat) outside of the refrigerator box (inside the cabinet just outboard of our refrigerator) in the hopes that the drier environment would extend its lifespan. To maximize airflow to the compressor, it was mounted outside of the cabinets and under our gimbaled stove.
Frigoboat K50 Compressor

We purchased 20" deep Rubbermaid TightMesh coated wire shelving that we cut to size to give us two shelves. We found that we could fit 2 3-gallon Rubbermaid Roughneck Storage Boxes at the base of our refrigerator to serve as our "crisper" drawers. Bill cut a scrap piece of Lexan to fit on the lower shelf to protect the food in our "crisper" from getting too cold.
Our custom refrigerator shelves and "crisper" drawers

We gave our old refrigerator door a face lift by installing a stainless steel front, and we were finally ready to install the door, fire up the compressor, and see how our system worked.
Our "new" refrigerator door
At first pass, the compressor fired up but the evaporator plate didn't frost over and the incoming capillary tube was freezing -- something that's not supposed to happen. We did some troubleshooting online and contacted Coastal Climate Control for technical support. They suggested that we needed to buy a Filter-Drier Tube to remove moisture from the system and address capillary tube blockage caused by the moisture. Lucky for us, they're located in Annapolis, so we drove over, picked up the drier and came home to install it between the keel cooler and the evaporator plate. We were careful to ensure that the drier tube was vertically mounted, as instructed.  [Not sure why it's not included as part of the kit, but that's another story].
Frigoboat Filter-Drier installed between the keel cooler and the evaporator plate
Hopeful that the drier would do the trick, we fired up the compressor and tried again. It certainly helped prevent the incoming capillary tube before the evaporator from completely icing over, but the system was still not working correctly. Frigoboat systems come pre-charged with R134A refrigerant, but apparently our charge was low.

We purchased an air conditioning R134A manifold gauge set and some R134A refrigerant to charge the system. Unlike a car where you actually use the gauges to determine when you've added enough refrigerant, Frigoboats require a bit more "finesse." The system is charged when the evaporator plate
just starts to frost over the whole evaporator plate, regardless of the gauge reading.

After Bill charged the system, we finally had a wonderful, efficient, working refrigeration system on Phoenix! The compressor is super quiet, draws very little power, and allows ample space for provisioning!

Building and installing our refrigerator was quite a process, but it was worth the wait! Our endless search for block ice is over and no more races to drain the coolers before our floating Ziploc bags filled with water and spoiled our food!

Another successful upgrade!

1 comment:

  1. Very impressive. Good work. Its been a long time coming. I'm glad that the box that David and I built worked out for you.