Ice box conversion to refrigeration

[Jim Walsh]

Fall projects.....about the only positive aspect of the end of another season. This is my first, and largest project this year.
Orion has a large and fairly well insulated ice box. I can easily fit seventy pounds of block ice and lots of pre-frozen and fresh food for those times when I’ll be away from any place I can find more ice, for 7 to 10 days. I’ve grown weary of shagging ice though.
This summer I decided to convert my icebox to a fridge with one of the Isotherm conversion kits. After reading and re-reading all the literature I could find I hoped to be able to make an informed decision as to what would be best for me.
I finally settled on the Isotherm 2050 SP water cooled component system. Before I made the actual purchase I downloaded their literature and built cardboard mockups of the compressor and the evaporator to allow me to decide exactly where I could fit the components and be certain I would not have to gut any of my cabinetry. I was not about to begin a demolition project.
I knew it would be advantageous to add additional insulation to my icebox but I was very open to suggestions on how best to accomplish this task. I considered purchasing a Isotherm insulation panel kit until I spoke to a friend who had converted his icebox to a fridge, and insulated his existing icebox, several years ago....albeit in a much larger boat....for a protracted Bahamas cruise. He explained he had used a sheet of closed cell foam, shaped to fit, and had used 3/16 fiberglass sheet stock for the new interior surface. He also managed the modification without altering his existing top loading icebox countertop access. This is what I thought best for my application.
He informed me of a local company which he has frequently used in his job supporting the USCG Academy sailing fleet...L.B.I.
https://www.lbifiberglass.com/
I purchased a sheet of 1” closed cell foam from Home Depot and spent a couple days lining the inside of my icebox, through the top loading hatch, and I had to resist any urge to bend any piece since the final fiberglass liner was essentially incapable of taking any bend at all unless I was going to introduce mechanical fastenings....which I wasn’t. It took a lot of finessing since the inside of the box had no straight flat surfaces. When I was done it was faceted....nothing but straight flat surfaces of foam awaiting the fiberglass outer layer. Any voids between the new closed cell foam and the curved surfaces of the ice box were filled (to the best of my ability) with pieces of closed cell foam shaped with a wood rasp and lots of cursing.
Now that the foam board was in place I made patterns out of rosin paper (the old hardwood floor underlayment) and I brought those to LBI to purchase a sheet of their 3/16 GPO1. I had heard that if I supplied the patterns they could water jet my material. It was a bit pricey but I had them water jet my material to the patterns I supplied and I only had to lightly trim two of eight pieces for an exact fit. In my case exact fit is a euphemism....I’m not skilled or talented enough to put “exact” to practical use.
I took my fiberglass pieces home and applied two coats of Interlux Brightside. Next I used a notched trowel to spread 4200 Fast Cure onto the pieces and pressed them into place. I wanted some squeeze-out between the pieces and it varies from “some” to “lots”. I cleaned up what I could but there is a point where you go from making something neater to making something worse....I was indeed pressing the envelope. I used odd scrap pieces of the foam as props while the 4200 cured overnight.
Now that this portion of the project was completed ( I have some high tech engine compartment insulation to insulate my icebox cover waiting to be installed) I purchased the fridge kit.
Upon opening the box the first thing I did was ensure my cardboard mockups reflected the proportions of the components, one never knows when an engineering change will be incorporated and I wanted to ensure my components fit my spaces precisely. No problems so far.
I also found my kit included a ball valve sea cock which had not been listed in the contents of the kit...but was available as an optional extra. Free stuff is always good.
Let me explain the kit I chose, the “2050 SP water cooled” kit. It includes a Danfoss compressor, an “L” shaped evaporator, a throughhull (which is designed to take the place of your galley sinks existing throughhull but incorporates a heat exchanger...since the unit I chose is water cooled, not air cooled, and a thermostat.
The water cooled version is said to be more efficient than the air cooled version so I figured that was the smart choice....who knows.
The actual installation was a bit daunting but went well....no broken parts and everything went together as advertised. I installed the compressor first. I found that it fit neatly under the sink in its included bracket and sits in what had been unused real estate....rare in a small boat. Next it was time to install the evaporator in the icebox.....excuse me....in my new fridge....which was a bit daunting since the refrigerant lines which run to the compressor are coiled up and permanently attached to the evaporator. Once the evaporator has been mounted the lines have to be (gingerly) uncoiled and routed to the compressor. In my case the only practical routing was from the evaporator, through a hole drilled from my fridge to the stove cutout, led beside and beneath the stove, through another bulkhead which led to the galley sink cabinet and the compressor. This meant I had to lift the stove out of the gimbal brackets and position it out of my way while running and anchoring the lines. I used a four part tackle to lift the stove and shift it around a few times before setting it back in place. It’s amazing what you can do yourself with a little mechanical advantage. Once that was done it was time to tackle removing my seacock and throughhull so I could install the new replacement throughhull which incorporates the heat exchanger.
The installation instructions said to drive a wooden bung into your existing throughhull and use that to center a hole saw. Drill the new 2 1/2” hole and draw your old seacock and throughhull out in one piece from the inside......very daunting to say the least. It worked like a charm....easiest part of the whole installation. Of course Cape Dory’s are built like tanks so I had to remove the two 1/4” flathead machine screws that anchor our excellent Spartan seacocks to the hull. It was very difficult at first, then I used my Dremel to cut them off from the inside and drove them out from inside. Nothing that’s been sitting for 35 years like to be removed using conventional means.
I used 4200 to bed the throughhull and tightened the inside retaining nut after using blue thread lock to ensure it behaves itself. The original backing plate was a piece of 1/2” ply that was in perfect shape. I sealed the surface with some old G-Flex I had just to make me feel like I was doing something useful before installing the new throughhull. Next I installed the gift ball valve seacock (yes, it pained me to have one ball valve in a Spartan seacock equipped Cape Dory) and also used blue threadlock on it. I replaced the drain hose from the galley sink to the new seacock....and double hose clamped it at both ends....just like the original.
Now I was ready to connect the three refrigeration lines from the compressor to the evaporator. They are all pre-loaded with refrigerant, you just have to seat the male and female connectors properly....no stress there.....yeah right. Apparently I did everything correctly because after I ran the power lines to the breaker panel and powered up .....it worked!
I have run the unit for about five hours and it works fine....out of the water. In the spring when I’m back in the water I will be able to set the thermostat and never have to shag a block of ice again.....fingers crossed....

[Jim Walsh]

More pics.

[Jim Walsh]

More pics.

[Jim Walsh]

More pics.

[John Stone]

Nice work Jim. You made a hard project about as reasonable as possible.

I’ll be interested to know how well it works and how many ah per day it uses when you are in Bermuda (warmer water). The compressor looks very small. Is that because it’s water cooled?

Thanks for posting.

[Jim Walsh]

Nice work Jim. You made a hard project about as reasonable as possible.

I’ll be interested to know how well it works and how many ah per day to the u it uses when you are in Bermuda. The compressor looks very small. Is that because it’s water cooled?

Thanks for posting.

It’s the same compressor used on the air cooled models, just lacking a small fan. Testing it out of the water it hit 3.9 AH for short periods then it went to zero. Once the box has something in it and it’s in the water in use for a few weeks I’ll have some real info.

[Frenchy]

Great post, Jim. This is something I've been thinking about for a while. You've made it a bit less intimidating for
me. Your conversion looks clean and neat.
I'm also curious about power usage and whether you'll need to add a solar panel or wind generator. I only have
a 45 watt solar panel, so I would probably have to add a panel or run the engine once in a while.
Thanks for posting - nice pics! - Jean

[Keith]

great post Jim!

As always scanned the the pics before I read everything and had a bit of a cringe when I saw that you had to replace the Spartan seacock. So when I finally read you text I just smiled when I saw your comment on the seacock.

Keith

[Jim Walsh]

Finally got around to insulating the lid. I wanted to retain the original so a major modification was not considered. I thought of using the same closed cell material I’d used to insulate the box but covering it with fiberglass would have added too much weight. A friend had just added some insulation to his engine compartment with some very light sandwich type material that he said is very effective. I asked if he had any left over....I needed less than two square feet...and he said yes. He was kind enough to offer his remnants and the tape he had left.
It was a simple matter to cut a couple rectangles out and I used 4200 to glue them to the lid. The next day I taped the edges.
I’ll find out how they perform next summer. If nothing else, I’ll have the quietest fridge in the fleet

[fmueller]

nice Jim ... if I had your energy I would improve the r factor of my ice box ... maybe someday. I put a similar but smaller Isotherm water cooled unit into my 27.

https://www.defender.com/product.jsp?pa ... id=5579968

https://www.defender.com/expanded.jsp?p ... id=5579968

This is a smaller plate type system where the plate sort of freezes as if it were a block of ice. Things placed right by the plate which is mounted vertically on one side of the box, tend to stay frozen, including cubed ice, Items in the other half of the box or on the little wood shelves just stay cooled (ie beers, butter, eggs etc).

I posted pictures a while back ... what I can report is that the water cooled aspect seems to work just fine and my little unit is nearly silent sitting on a shelf in the starboard locker. Since I have shore power at the Yacht Club marina, I effectively have a little fridge now, and it really really works. Very happy with the outcome. I've done some multi day overnighters and don't seem to be running past my batteries if I motor for an hour or two per day but I think my next improvement should be a battery meter like you installed, because I'm flying blind with respect to power use.

Just seat of the pants, it seems to run about 10 min out of an hour, but in 5 minute bursts when I'm on shore power. Since it draws 6 amps - that rather conveniently works out to 24 amp hours a day. But I'd like to know for certain.

cheers

Fred

[Jim Walsh]

Good to hear from someone with experience with one of the water cooled units. I’m looking forward to putting the unit to full use next season. This is the first boat I’ve ever had which has had refrigeration so it’ll be quite a novelty.

[Jim Walsh]

Early AH figures are in. The sea water temp is currently 59.2° and I have averaged 15.8 AH consumed daily. I’ll report back, as the water warms, for those who may be interested. I’m very happy so far.

[John Stone]

Good info Jim. I’m interested. No doubt about it. 15 ah daily is ridiculously low. Be interested in how it performs when you are in Bermuda next time. Keep the info coming.