David Tyler wrote:

I fear that at this late stage in the build of Fánshì, a fridge must be very much an afterthought. It was for Tystie, and when we got down to warmer climes and were in need of a beer that was cooler than lukewarm, I bought an Indel Webasto BI29 (I think it was, or something similar, anyway). It fitted underneath the chart table, the only feasible space (I don't know where on Fánshì there would be room). It has the Danfoss compressor, which is good, but has little insulation, and is un-repairable if the copper capillary tubing gets salt water on it and corrodes through (guess how I know?). It really needs to be installed with extra slabs of foam around the sides and bottom. Failing that, it can still be run at 10˚ less than ambient temperature to save on power - when the air and water temperatures outside are 30˚, a beer at 20˚, while not ideal, feels cool, and markedly better than a beer at 30˚.

That Indel fridge looks to be not nearly as well designed as the Waeco units with the exposed compressor etc. The Waeco units have everything contained within the casing, and although insulation is probably minimum they still seem to work very efficiently keeping the temperature down at a safe 4 degrees Celsius, and cooler if desired. I am sure that if keeping the champers cool was a priority for Annie then she would find space to fit a small fridge. Of course it needs to be powered which requires sufficient solar panels, regulator, and battery capacity, all of which can equal the cost of the fridge. For those interested in the costs in this part of the world; 2 x 60 watt solar panels $140, 20 amp MPPT solar controller and remote meter $240, 130AH deep cycle AGM battery $347. Add in about $50 of wiring and consumables. Interesting that the solar panels now cost a lot less than a good quality solar controller. I made my solar panel mounts out of material I had lying around at home so there was no cost there apart from my own time, but my mounts were based on the design of a tracking solar panel mount which costs $850 for the kit. I saved some money there! The fridge compressor kit cost $750 which was a trade price, they cost a lot more retail in NZ.

What price cold beer?! 

On our 40 cat I built a fridge and a freezer. 

Both used Danfoss BD35F compressors with keel coolers which is the absolute minimum power consumption configuration for these units. It does not require a radiator or radiator cooling fan. 

We used electronic thermostat controls which allowed for moving both start and stop set points and had a nice LED display in the galley so you could keep an eye on things.

4 inches insulation for the fridge and 6 for the freezer - except where we could fit more. Took it all the way to the hull. Most insulation required on the underneath of the boxes of course.

This gave us some redundancy although neither unit ever gave any trouble.

We had a fridge tech from Southampton gas it up. He had been running a business in the caribbean but came back to run his dads business when his dad got ill. He knew his stuff. Said to use the BD35 because they are super reliable but parts are available everywhere. You pay a premium for the "self assembly" pre-charged pipes with self assembly unions. Better to just get a fridge tech to plumb it up - you need smaller holes in the bulkheads and teh pipes can be correct length.

We had plates that wrapped around the full perimeter of the boxes by sizing our boxes to what was available.

We used double seals (i.e. two rows) on the box lids and positive pressure latches (like teh old 1930s fridges had) 

All worked like a charm even when water and air temps were high.

Sadly I followed the designers positioning of the boxes without thinking and put them on the outside of the hull. It would have been much smarter to have them on the inside where they would have been shaded. doh ! 

The box building is no more difficult than things Annie has already done, but it does involve sticky stuff and closed cell foam which tends towards friable which can be a bit dusty until sealed up.

Just remember that if the box is not completely filled it will require baffles or the champers will be over-excited on opening. And do refill teh fridge promptly - you don't want to be trying to cool air.

Annie Hill Wrote:

If you find out anything that you feel is worth sharing, would you mind starting a new thread about it?  I haven't entirely dismissed the idea of a small fridge - the bubbly tends to be too excitable when it's really warm ;-)

Annie is still considering some form of refrigeration in her 'soon to be completed' (!), build, and I like to keep my tonic water cold, not to mention other food items which are best kept chilled. I have cruised without refrigeration but I certainly enjoy the convenience of being able to keep perishable food items chilled, and of course there is the luxury of cold beverages. Over the years and with various boats I have had complete success with 12 volt refrigeration so in order to benefit those who are thinking about refrigeration here is a summary of my experiences.

Many vessels are still fitted with eutectic refrigeration systems where cooling is provided by an engine driven air conditioning compressor. These systems are complicated to install, expensive, and based on my years of operation boat charter fleets, require constant ongoing maintenance. An electric refrigeration system is far better in terms of initial cost, ease of installation, performance, and maintenance free operation. Of the four different 12 volt refrigeration systems I have had over an actual 20 year usage time I never experienced and failures or maintenance issues with 12 volt refrigeration. Each of these fridges utilised a Danfoss 12 volt refrigeration compressor and evaporator plate, the last 3 fridges being a Danfoss BD 35 compressor.

The first of the four fridges, over 25 years ago was a front opening unit of about 50 liters capacity with an ice maker compartment. This unit did seem to consume a lot of power, but probably being front opening most of the cold was lost each time the door was opened. Nevertheless I had five years of successful use out of this fridge before I sold the boat. The next two boats were fitted with 'off the shelf' Waeco chest fridges, one of 18 liters capacity, and the second 35 liters capacity. These Waeco fridges come complete as a plug-in and go system, all that is needed is space to put the fridge and a nearby 12 volt power source. Both of these Waeco fridges were powered via solar panels and AGM batteries, and have provided years of trouble-free performance. For a family of three the 35 liter fridge provided just enough space for a week to 10 days of cruising, and even over the three months of our cruise to New Caledonia in 2014 provided sufficient space to meet our provisioning needs.

When we purchased our current pointy rig boat a few months ago the boat came with a well constructed ice-box of about 90 liters capacity. The previous owners of 30 years had made this work by freezing large blocks of ice. The idea of simple refrigeration appealed but we could not make it work that well. There was a large temperature variation between the top and bottom of the very deep ice-box, and the ice only lasted several days. So, based on the success of my previous fridges I decided to fit a kit set refrigeration unit. I chose the basic Isotherm air cooled unit suitable for fridges of up to 80 liters and using the same Danfoss BD 35 compressor. I reduced the capacity of the ice-box by installing a false floor with insulation under so the capacity is now 72 liters. There is 80mm of insulation on the sides and top of the ice box. Installation of the compressor unit took about a day including the electrical connection. It was fairly fiddly work including having to mount the compressor in a very narrow space at the back of the icebox. A little bit of cursing happened from time to time! Fortunately Isotherm provide a very handy mounting bracket for the compressor which makes mounting in a tight space a little easier because once the bracket is installed the compressor unit simply clips onto the bracket. To power the fridge compressor I installed two 60 watt solar panels, an MPPT solar controller, and a new 130 amp hour AGM deep cycle battery. We have now had several months of usage out of this installation and so far it is a complete success. I don't know what the actual power consumption is but it is negligible with the battery usually being back up to fully charged by about the middle of each day provided we have some sun through the morning.

For my little catamaran which is currently under build I will go back to a Waeco fridge, probably either the 11 or 18 liter unit due to a lack of internal space, and I will install the same solar power system to run the fridge and other electrical requirements of the boat. Engel fridges utilise a different type of compressor unit which apparently uses less power than the Danfoss compressors, but based on the low usage of the Danfoss compressors I don't know that it is worth the extra cost of the Engel units. 

The attached photo shows a view of the Icebox which sits under the chart table, and the fridge compressor sits in the locker to the right of and below the chart table, but around at the back of the ice box,so it was rather tight getting the compressor in there and doing all the connections, but worth the effort for a tidy installation.