Engine driven Frige Yes/No

[Tjurd]

Hi Guys,

We bought a Beneteau Oceanis 430 a while back and in the process of fixing her up to become a blue water cruiser for extended cruising .

My question is;
The boats fridge has two evaporators, one for the traditional fridge compressor, and one for the engine driven (airco) pump. Both separate systems.

The engine driven (airco) pump is busted, I think I can replace it quite easy with a new one used on cars, but....

-Why would I want an engine driven fridge?
-Why did the previous owner fit her with one? (probably the same answer as above)
-Is it a plus for our intended cruising? (as much sailing as possible, solar for elec.)

Hope to hear from you guys.

[SV THIRD DAY]

Engine driven system were once our bread and butter...but once the efficient 12v compressors came onto the scene, they became obsolete for cruising boats. Why...because you will be having to run your engine once or twice a day (based on quality of insulation, box volume, etc) to keep your food cold. Take a day trip off the boat...loose your food. Having sold thousands of the engine driven systems, now when people call us with them, we don't rehab them, we replace them with a 12v system. There is already a lot to do on a cruising boat to keep it going...why add refrigeration to the list. Set it and forget it. So what we do now is rehab those old holding plates and use them with a 12v compressor running off batteries/solar.

[annsni]

We coastal cruise for a few weeks at a time and find the engine driven system to be wonderful. It's only not so great when we are at a dock but the number of times we stay more than 12 hours or so at a dock is so minimal that we don't worry about getting a 12v drive for it. We use the time both in the morning and the evening to do some cleaning up (usually right after breakfast before we do anything for the day and then after dinner as we clean up from dinner and prepare for the night). We can usually keep the fridge cold and freezer frozen on 30 minutes twice a day but many times we've been able to skip it just because the plates have held really well. We are usually on the move so we just run the fridge/freezer while we are underway and even if we stop the engines to sail, we usually have them on to start to get out of the harbor and to end the day coming in. I can see how if you lived on board it might be more of an issue because I've seen live boards stay at docks or in one place longer. When we have just 3 weeks, we want to try to hit up all of the places we love to go so we rarely stay in one place more than 3-4 days.

[Rob seadog]

Hi there,
we are sailing up East coast Australia and like our engine driven compressor fridge.It was on the boat when we bought it as well as a 240V inverter fridge. We find we use our engine a lot due to weather/sea conditions, as well as making barways in time for the tide/current. If we are in one place for a couple of weeks we can see the desireability of a 12V fridge run off solar/wind generator.We currently dont have enough solar/wind generating capacity to meet our electrical needs but these items our on our shopping list for when finances permit.
The engine driven compressor fridge can quickly cool or freeze and the eutectic tank/plate maintains the cold for up to 2 days on our boat.In the event of some electrical failure/lack of sun light or wind, it is good to have an alternative means of refrigeration.Hope this helps.
Cheers,
Robseadog.

[Sandero]

I installed an engine drive when I set off cruising. The reasons were:

I would use my engine at least a few hours on a typical day to charge batts, make hot water and... run the refer.

If I didn't need to charge with the engine... or need hot water which came from the engine heat exchanger... I would have rely on 12v refer and then need some some serious battery charging... from a noisy generator... a farm of solar panels.... and or a high out put wind gen and of course very large batts. I had a pair of 8Ds and a couple of panels to keep the batts topped up at anchor. This worked for me.... and continues to living on the mooring on the weekends a local cruising.

[RaymondR]

If you already have it I would fix it and keep it. There are a number of reasons for doing this.


Since 2001 I have permanently lived aboard and coastal cruised. My backup for my fridge/freezer is about two dozen Mason Jars and a pressure cooker. If the fridge/freezer goes down I madly start cooking and preserving rather than be without food supplies. Much easier to run the eutectic an hour or so a day until the cycling fridge is repaired.


I have about 900 amp hours of storage and 500 Watts of panels but with running all the nav equipment, lights and house gear if I get a few overcast days I have to run a gen set to charge batteries. The most consistently used heavy draw on the batteries is the cycling fridge and being able to switch it off and rely upon the eutectic would help. With getting in and out of anchorages and light winds I would pretty well always run the engine an hour or so a day anyway which would probably be enough to pull down a eutectic.


I am rebuilding my constant cycling system as a eutectic system but will retain the 12V Danfoss compressor in order to be able to carry over the refrigeration in the box during those periods of the day when there is no solar power available. A 24 hour 7 day timer switches the compressor on about 3 hours after sunrise and off again before sunset, this allows the batteries to top up in the mornings and afternoons whilst the sun is shining. I have found that this results in very little battery pull down which extends battery life and also provides a hold over period if the fridge quits - it's cheaper to store cold in a eutectic fluid than electricity in expensive deep cycle batteries.

[undercutter]

I,m with Third Day, however you can use the mounting plate to run a larger additional engine driven alternator in place of the compressor. This will more than make up for the energy consumption of the 12v compressor system when you are motoring.

In addition we recently purchased a stand alone chest fridge/freezer that amazingly only draws 5 amps @12v when running. That thing is a beauty with fantastic insulation. And it is portable as well so you can actually take it with you if required and plugs into either AC or DC power supply though at 90l it may be a little big to lug around.

[sailorboy1]

My boat is out on it's mooring all week with the 12V refrigeration running. You can't do this with an engine driven system (unless you have a start system). A single 290W solar panel keeps the batteries charged and has been doing so for 4 years. And before someone goes "yeah but what if there isn't sun", it has been overcast an rainy for the last 6 days and when I went to the boat the batteries were down 2 AH.

[SV THIRD DAY]

Engine driven refrigeration has some of the same "Siren Song" allure to cruisers looking for "free power" as an engine driven water maker. But as someone who is on year 9 of full time living aboard at anchor or on a mooring, I can tell you running your main engine (the most expensive piece of equipment on your boat) to make power, water, hot water, refrigeration or to relax you with the rumble certainly ain't free anything!

[wsmurdoch]

We have both engine drive (which we use away from the marina for 5 months of the year) and 120v (which we use when we are in our marina when we are not cruising). The two systems are completely separate except that each has its own evaporator coil in a single holding plate. The engine drive system also has a short finned tube and fan evaporator in the freezer section.

If you plan to work on the engine drive system, get Richard Kollman's book "Do It Yourself Boat Refrigeration". Kollmann Marine

We run the engine one to one and a half hours a day in the Bahamas keeping meat frozen, making ice, and chilling the beer. Many times the engine run time occurs when we are moving the boat and would be running the engine anyway. The cooling capacity of our engine drive system is quite large allowing us to quickly freeze ice, chill fish, etc... things that would take much longer with a smaller BD-35 system. The system is a Kollmann Marine Products system from perhaps 1988. We are in the Bahamas now on our ninth trip.

Irish Eyes to the Bahamas

[jeremiason]

I am wondering what this does to your fuel mileage and horsepower?

Running an AC Compressor effects larger engines significantly, so I would assume it does the same thing using a Refrigerator Compressor...

I think the Oceanis only has only 45 gallons of usable fuel... Are you cruising?

[jstevens]

I installed an engine drive system on my boat about 15 years ago as a second compressor. It works great for day-hop cruising as the engine time in the morning leaving the anchorage and in the evening entering an anchorage are all that is needed. When living on the hook for more than a few days a 12v system is preferred.
That said, if the newer 12v systems had been available when I made my system configuration I would likely not have gone with the engine-drive.

John

[barnaclejim]

We also have both engine driven and 12 volt Sea Frost system. The advantage of the engine driven one is that it is a much bigger compressor and makes everything cold very fast. The 12V system is small and slower. I have not noticed any significant power loss from the engine and as we have been in the Med for the last 5 years we do a lot of motoring. We only use it when we need the engine. It is more mechanical stuff to maintain but such is our shared curse/ burden/ fetish.

[JPA Cate]

Tjurd,

What you're reading here, has not taken into account where you are, and you live somewhere colder than many of us. This will affect your needs for cold. For example, in San Francisco, we used to cool beer in the bilge, because the water's pretty cool there. Then when you go to the tropics, all of a sudden you need far more refrigerative capacity.

My own sense of it is that, as you said, it would be inexpensive to replace the pump, and that would give you a backup. Perhaps, as Rich Boren suggested, the holding plates might need re-habbing, and maybe he will come back and say why, and what they do to re-hab them. I certainly agree with him in that I wouldn't want to have to use my main engine to run refrigeration, but a backup for when the battery bank is down, that is already in place, might be convenient some time. [Our system is only 12 v., with all the solar panels on the radar arch. Jim added a semi-flexible panel on top the dodger, and it still is not quite enough when it is overcast. In short daylight times, we have to use our engine to charge the batteries, so some of its work is refrigerative, via charging the batteries. Compromises, compromises, eh?]

Ann

[SV THIRD DAY]

Originally Posted by Ann T. Cate

Perhaps, as Rich Boren suggested, the holding plates might need re-habbing, and maybe he will come back and say why, and what they do to re-hab them.

Re-habbing a holding plate is pretty easy if the system is already using R134a, as a refrigerant. You would just leave the plate alone and change the lines going to your old compressor to a new 12v compressor unit. Recharge and off you go. Since holding plates rarely if ever go bad, there are 30yr old and even older holding plates cruising around out there just like they did when brand new.

The reality however, is that most older engine and 120v systems are R12, so you have a little work to use them on the R134a system.
1. You will need to remove and replace the R12 expansion valve for a R134a valve.
2. Since the R12 oil is not compatible with the R134a refrigerant, you will need to blow acetone through your refrigerant lines and holding plate to clean it out. Then vacuum it down and off you go.

The same holding plate used on an engine or 120v AC system will work with a 12v compressor BUT...as it has been said above. The engine driven or 120v AC compressor is HUGE in BTU removal rate compared to the 12v compressor. So the bad is that you will not have a fast holding plate start up time from a warm box/plate start-up. The good is that it will turn itself on/off based on the thermostat so it is a set-it and forget it with more stable box temps.