Fridge planning

[GILow]

Hello Cruisers,

This is kind of a "how long is a piece of string?" question, but hopefully someone will be able to put some boundaries on things for me.

Quick backstory: Our boat was fitted with a new galley in the mid 90's and as part of the fitout scored a pretty well made top loading engine driven eutectic freezer of 136 litres capacity. The insulation was generous, and still appears to be dry and in good condition, though I concede that appearances can be deceiving. Alas, the engine bay components of the system were completely and totally buggered (due to raw water leaks) and are now at the scrap metal recyclers. So, in other words, I have what appears to be 136 litre top loading, well insulated box in a good spot in the galley.

The boat also has an upright, 120 litre Fischer & Paykel fridge, which had me REALLY confused until I realised it had been retro fitted with a 12 volt Danfoss compressor, rated for a 160 litre fridge. The upright fridge is in an inconvenient spot in the passage to the rear cabin, and is mounted so that on a starboard tack everything falls out if you open the door.

The Danfoss draws about 4.5 amps and has no trouble at all keeping the fridge cold, running for about 10 minutes per hour on average. So clearly it is in ok condition.

There's what we have.

So, bolt of lightening moment, I wonder, should I transfer the Danfoss to the chest freezer box, and I will have (hopefully) a decent 136 litre fridge that won't chew up every spare electron on the boat and I won't have to change tacks to make a sandwich.

Then, I asked myself, is 136 litres adequate for coastal cruising around Oz? If not, can I do something clever with the spot I have created, say fit an Isotherm unit suited for the 400 litre fridge to a well made and insulated chest like the one we already have, and there's enough space there to build a box up to 400 litres with good insulation, which may be more than I need. (FWIW, storage space on our boat is very generous, so building a big fridge in that spot is not a problem.) Then the 136 litre box becomes the freezer, and the bigger unit becomes the fridge. (not sure if the Danfoss will be able to freeze 136 litres, so I might have to shrink that box with a bit more insulation). In the interim, I feel like the 136 litre fridge should be adequate for weekending and the odd longer journey.

But I realise I have NO idea about how much fridge space we need on a boat.

What sort of volume should I be planning on for a couple who are serious cooks without being food snobs, who plan to coastal cruise around Oz?

Does my proposed dual cold storage solution make sense, or have I missed something important?

On the power side of the equation, we have a pretty decent old wind generator (Aerogen 6, just refurbished, up to 350 - 400 watts generating capacity, ) and I have just installed 280 watts of solar panels with a MPPT regulator, with capacity to install another 200 watts on the Bimini. There is also a Hitachi 100Amp dedicated house bank alternator on the engine. There are no other major drains on the battery, and we are planning to fit at least 200 USEABLE amp hours of SOME sort of battery technology, not sure if it will be lead acid, lithium or some other technology.


Ideas? Will this layout work? Is there a better approach? How much fridge volume do you think we will need? Is 136 litres of fridge likely to be adequate, in which case should I simply supplement it with a dedicated portable 12 volt freezer when needed, such as a Waeco, around 40 litres or so?

Matt

[GordMay]

136 litre (± 4.8 Cu Ft) isn't a very large fridge, especially if you sail over a week between fresh re-provisionings.

[GILow]

Originally Posted by GordMay

136 litre (± 4.8 Cu Ft) isn't a very large fridge, especially if you sail over a week between fresh re-provisionings.

What do you think... good for three or four days at best?

Matt

[s/v Moondancer]

I have just accomplished what you face by replacing an old chest freezer and a separate refrigerator with two new drawer type Isotherm 5.5 cf units. One a two drawer freezer and one a two drawer refrigerator

We took out the old freezer and spent a day cutting out the woodwork and digging out the insulation and 2 days doing carpentry for a new worktop to fit the 2 drawer freezer. The refrigerator required less work and only took a day of carpentry.

The Isotherm units are over $2,500 US each! and do not cool to sea water but put the waste heat out into the cabin which is not a problem but requires excellent ventilation out of the housing. This has the advantage in that they work on the hard.

Both systems are 12/110 v dual systems and ours are running on 12v. Your battery system and solar panels are marginal for such a energy guzzling system. As I write I am running the generator to replenish 250 amp hours into my 1200 amp/hr batteries as my 425 watts of solar did not get any sun yesterday.

I would think smaller and drink less cold beer but like you I used to have to go on the starboard tack to get a cold beer out of refrigerator.

Good luck!

[GILow]

Originally Posted by s/v Moondancer

I have just accomplished what you face by replacing an old chest freezer and a separate refrigerator with two new drawer type Isotherm 5.5 cf units. One a two drawer freezer and one a two drawer refrigerator

We took out the old freezer and spent a day cutting out the woodwork and digging out the insulation and 2 days doing carpentry for a new worktop to fit the 2 drawer freezer. The refrigerator required less work and only took a day of carpentry.

The Isotherm units are over $2,500 US each! and do not cool to sea water but put the waste heat out into the cabin which is not a problem but requires excellent ventilation out of the housing. This has the advantage in that they work on the hard.

Both systems are 12/110 v dual systems and ours are running on 12v. Your battery system and solar panels are marginal for such a energy guzzling system. As I write I am running the generator to replenish 250 amp hours into my 1200 amp/hr batteries as my 425 watts of solar did not get any sun yesterday.

I would think smaller and drink less cold beer but like you I used to have to go on the starboard tack to get a cold beer out of refrigerator.

Good luck!

Hmmm.... your comment about the battery capacity being marginal has me worried. Which Isotherm kit did you install? The one I am looking at may be smaller as it is only AU$1200.

Matt

[s/v Moondancer]

Ours are medium ones, DR160 and we are close to the equator. It has only been running for 2 days so I am not sure how often it cycles. I will let you know the consumption when all is stable.

Phil

[JPA Cate]

Matt,

FWIW, we've been getting by all these years with about 70 l. total refrigeration capacity. You'll get a lot of different advice here, and we learned a lot about what needs to be refrigerated and what doesn't during the year we cruised without refrigeration. That said, we'd rather have more cold space, but there are sound reasons to continue as we are.

Part of how you make it work is that you purchase with limited space in mind, as in buying chicken breasts or thigh fillets instead of a whole chicken (unless for a special purpose). Density packing is the order of the day. Cryovac meats are your friend, keep extremely well, do NOT freeze. [We do not usually have ice, and so, would pre-chill tonic water if we wanted gin and tonics.] So, for us, it has been learning to work with what we have. Cabbage does not require refrigeration, so cabbage based salads help with the craving for fresh and crunchy, and lettuce is for sandwiches. Also, we eat very simply. Fruit, yoghurt, and toast for most breakfasts, a sandwich only for most lunches, and dinner is our main meal. We like green vegs. Brussels sprouts keep quite well, carrots, celery, zucchini. We do not refrigerate eggs, mayonnaise, onions, potatoes, or jams. (Yes, sometimes the jam ferments a little, but it doesn't hurt us.) Rough distribution is bottom third is meat -including the rare fish we catch-, remaining two thirds dairy and green veg. Most stuff keeps way longer than suggested use by dates. Those are for retailers, not cruising sailors, IMO.

You guys might find our way too constraining, but my point is that your 136 l. fridge MIGHT do just fine for you, if you try to make it work. Then the upright fridge could become dry storage or a pantry.

Ann

[GILow]

Originally Posted by s/v Moondancer

Ours are medium ones, DR160 and we are close to the equator. It has only been running for 2 days so I am not sure how often it cycles. I will let you know the consumption when all is stable.

Phil

I assume you are talking of the two drawer unit? Interesting figures given for those.

I don't completely understand the way they describe the power consumption... W/24hrs... I am used to measuring power consumed in Watt hours, but either way the variation between fridge mode and freezer mode is pretty big.

530 W/24hrs for fridge mode only
1100 W/24hrs for freezer mode or fridge plus freezer mode.

If those are watt hours then they are certainly too many for our humble system. The fridge would use up all of our solar power, even on a good day.

Matt

[GILow]

Originally Posted by Ann T. Cate

Matt,

FWIW, we've been getting by all these years with about 70 l. total refrigeration capacity....

Ann

Thank you Ann, terrific advice as usual.

I am not sure I can sell Sally on the idea of a G & T on the afterdeck without ice... but the Danfoss kit in the upright fridge does have a little freezer "box" that can do ice cubes, so we might be ok if we freeze nothing else.

I was actually wondering about laying the F & P fridge on it's back to make the other icebox/fridge, but maybe a pantry is also an option... Mind you, I've still got the same problem of needing to tack to use it.

Matt