Refrigeration - This is Cool

While we are working towards a goal of being as self-sufficient or "off the grid" as possible, we are not willing to deny ourselves some modern efficiencies.  While boat refrigeration has been available for a long time, in some applications having none may have been a much cooler idea!

On Poetry, our 1965 Pearson Vanguard, we attempted to benefit from refrigeration.  We had used blocks of ice and were less than enthused by the results.  Since we had remodeled the outward look of the galley, we didn't want to gut the whole thing to rebuild the icebox.  While having a better insulated box is KEY to the refrigeration thing, we felt that by rebuilding the box from the outside in would give us a box the size of a thimble.  We insulated the inside and installed a Grunert unit.  While it kept the box cool (read NOT cold), it ran 24 hours a day and never cycled.  The fault was the box, not the Grunert.

On Harmony, we had the perfect opportunity to rebuild the ice box area from scratch.  We had done all of the research about how to build a well insulated box.  However, we hadn't decided which unit to install for chilling the box.  There are many good companies, but we had to first choose whether to use an evaporate with a separate compressor or an engine driven cold plate.

OK, to set the stage, Harmony will have 2 cold boxes:  one will be a refrigerator, and the other will be a freezer.  However, we want to provide ourselves with an additional option of being able to use only one box while cruising for a long weekend or a week.  This will prevent us from having to fire up both boxes every time we sail and having to corral a separate cooler sliding around the sole.  So the refrigerator box will also be able to provide a small freezer compartment.

Now, our broader objective is to live on the boat sustainably without having to run the diesel to charge the batteries every day:  an ideal situation will find us using solar and wind to replenish the amps we use in a 24 hour period.  A vital necessity is to provide refrigeration with the lowest amperage draw as possible or the lowest need for engine hours as possible.

Since we only want to run the engine for propulsion in an ideal situation, we decided that an engine driven cold plate would not work for us.  Beyond the required engine hours to freeze the cold plate, the holding plate system would not work for us when we did short cruises over the weekend or for a week or so.

So, we narrowed our choice down to an evaporator plate with a separate compressor.  We would need two, one for the refrigerator and one for the freezer.  As I mentioned before there are many quality companies that provide this type of system:  Adler-Barbour, Sea Frost, Technautics, and Frigoboat, to name a few.  We needed an efficient compressor that came with a small footprint to enable us to mount it in a convenient enclosed space near the galley.

That narrowed the choice even further, actually down to two:  Sea Frost and Frigoboat.  We went to the 2012 Newport Boat Show to do our final evaluations and talk to the companies to get their perspective.  As so often happens at the boat shows, decisions are often finalized by those who are willing to actually discuss the subject with us.  I can still not fathom why vendors will not entertain a serious discussion with someone who is literally waving money in front of them!

We casually went to the Frigoboat booth, and a very pleasant person quickly gave the show spiel, but then did something unexpected.  She directed us to another booth where she said that we could get our more specific questions answered.  OK, nothing ventured nothing gained!  We journeyed over to the Great Water Marine Systems Booth and met Kathy Groh:  remember the hot water heater person!

Kathy was very helpful, as she listened to our prospective design ideas.  She offered her own perspectives and gave us a couple of options.  In a later discussion or what I can label as a design meeting, we finalized our choice.  We will use the Frigoboat keel cooler models for both boxes.
The refrigerator box will house a small bin shaped evaporator that will handle the chilling duties, but will also provide a small freezer for short cruises.  We will only have to fire this box up during our short cruises. 
The freezer box will house an evaporator panel and give us frozen food storage for the longer cruises.  The two compressors will fit perfectly under the salon berth just forward of the where the two boxes will be.
With between 3 to 4 inches of foam insulation, the reefer box will draw less than 1.0 amp an hour, while the freezer will less than 1.4 amps per hour.  As a combined system, the hourly amperage draw will be between 2.0 and 2.5.  Compared to what we have experienced before, this is miserly.  On top of that the compressors will be relatively quiet in operation.

Now, this is cool!  Even with giving ourselves the luxury of refrigeration, we will still be able to maintain a relatively small power usage footprint.  This should go a long way toward allowing the combined solar and wind power sources to supply the charging capacity we need in a 24 hour period.  More on this when we get near to building the boxes and installing the units!

Fair Winds and Following Seas!