Refrigeration

[Auzzee]

I currently have two separate freezers, both are cooled by eutectic plates, driven from a tecomseh compressor, which in turn is belt driven from the diesel. I am considering disconnecting the smaller of the two (72 litres) and installing a 12/240 volt system, so that I do not need to run the engine on a daily basis when at anchor. I have 160 watts of solar panels, and may buy a wind turbine to augment charging capacity. I currently have 840Ah in storage capacity. I am considering buying a Danfoss BD50 compressor and a 'U' shaped evaporation plate. Any advice re this syetem, or indeed any other, will be welcomed. Thanks. David

[Gallivanters]

Ahoy David!

I'm certainly no expert, but...

There have been some great advances in recent years and you may get a large variety replies at to which is the best way to go for efficient refrigeration upgrades.

In my opinion, Richard Kollerman (sp?) has the most informative book on the subject and you can contact him personally at www.rparts.com for suggestions. Nigel Calder also has a good book, too.

It's all theoretical but all seem to agree that water absorbs heat much more efficiently than air.

I am about to throw away our eutectic plates & engine compressor and replace it with a pair of frigoboat 12 v dc units which will be powered by eight 80 watt solar panels feeding eight Trojan T-105 six volt deep cycle batteries. I also have a 100 amp smart alternator on our new engine to help augment the power whenever necessary.

The system I'm going to install have both air and keel cooling for increased tropical efficiency. I'm installing two for increased cruising flexibility. Hopefully - it'll work completely by the power of the sun. Hopefully - it'll work while the boat's hauled out. Hopefully - there'll be enough power left to run a blender.

I installed a smaller air cooled Danfoss unit with rectangular evaporator on our last boat. It kept things frozen when placed inside the evaporator "box". We used three 45 watt solar panels feeding six of the same batteries mentioned above. It worked okay but we needed to run the engine for an overnight recharge when the charge dropped to 12.2 volts - about every five days - depending on the climate. That fridge never let me down from Guam to the Caribbean.

Again - it's all theoretical... all I know is that I get great satisfaction from a cold beer while anchored in pristine, remote locations and the moment can be shattered by having to run my engine in order to make it happen.

Let me know how it all works out, okay.

Cheers,

Kirk

[Auzzee]

Thanks Kirk for the advice and i'net link. 8 x 80w solar panels, that's going to take a lot of room. Where will you mount them?

Cheers. David

[Gallivanters]

Hi David,

Half are going on the hard top over our centre cockpit and the other half will be mounted on a stern arch which is presently being completed.

The pannels are SHARP model NE-80EJE and each measure just under 2 x 4 ft (537 x 1200). We have a terrific rebate program going here and I aquired eight 80 watt panels for $1200 USD = $150 USD each.

I'm planning to use an OUTBACK controller.

Granted, it's going to be expensive when complete - biggest cost is fabrication of the arch & hard top, but I reckon it's not too uncommon for "dirt dwellers" spend this kind of dough on home additions, lawn mowers & roof tiles... all of which we've escaped by answering The Call...

I'm sure it's a wise investment in our future cruising pleasures.

WHERE are you heading in SE Asia? We spent a year meandering through the Philippines, Borneo & Malaca Straits back in 2000 - 01. We loved Kuching, Johor Baru, Penang, Langkawi and the Phuket region... ALL of it. Best part was the food! Chili Crab cooled with Tiger Beer! Yum!

Enjoy your adventure - we're not too far behind you.

Kirk

[Auzzee]

$150 each...That's amazing. As my boat has a canoe stern, the alternatives for placement of panels is not so clear, but I can exchange the 2 x 40 for 2 x 80. I am impressed with the Frigoboat system and will enquire further.

I am planning to sail from Darwin to Thailand, Malaysia, Philippines, Palau, Taiwan, Japan. I'm still deciding whteher I should leave with the trades in April, or wait for the Darwin to Ambon race in late June.

But then again, who cares? The wind blows, the boat goes, the beer is cold and liff is good!

David

[Gallivanters]

Ahoy David!

Log onto the CRUISERS & SAILING FORUM and go to FRIGABOAT topic to have a look at what some other users (and sellers) think about the fridge system I was thinking about purchasing!

I may need to re-think this.

Cheers!

Kirk

[Auzzee]

Thanks for that Kirk. It presents a perspective that is not appealing. My only experience with 12v systems was when I self installed a Waeco BD35F compressor and eutectic holding plate in a previous boat. I was super impressed, but as with all holding plate systems, the only thermostatic control is 'bloody cold' or 'bugger it'. I'll keep researching.

Cheers

David

[Gallivanters]

David,

How long did it take the 12V BD35 compressor to freeze the eutectic plates?

And... after the initial pull down - how long / often would the compressor cycle to keep them frozen??

I've been told by the "experts" that small 12V compressors will not work with eutectic holding plates... especially THREE of them, like I have.

I really wish to get away from the engine driven compressor. It's just such a shame to have to throw away the three holding plates and start all over.

Nigel Calder's book suggests using a 1/2 hp 12V compressor system provided one has the batteries and means to keep them charged... but this type compressor would cost me as much two complete Waeco based systems...

Hmmmmmmmmm...

Kirk

[Trim50]

Take a look at Technautics cool blue...we have been extremely pleased with its performance.

http://www.technauticsinc.com

[Auzzee]

The waeco/isotherm/danfoss system can be ordered with a compatable holding plate. It is relatively small, but freezes quickly. Used in conjunction with a heat exchange unit which replaces the galley sink through hull, the system worked very well in my 27' sloop. The freezer box was 60 litres. I understand a larger holding plate can be bought to suit the larger BD50 compressor.

I tested the unit with one 40 watt solar panel and a 120 ah deep cycle battery. Bearing in mind that in Darwin we have 400 hours of sunshine each day, the unit shut down through lack of power after six days. During that time the freezer was empty.There was a 20 litre 'spill over' box which had 12 beers in it on day one....but sadly was empty by day 5.

I really like my engine driven system, but it is a pain when at anchor. This is why I only want to put 12v refrigeration in one box.

Interestingly Cornell's ARC 2000 survey showed Isotherm to be the most popular 12v system (30%), followed by Frigoboat (13%) and Grunert (3%). It seems that the engine driven system, which just 15 years ago was the height of hi-tech sophistication, now brands us as ludites....Durn it.

[Trim50]

"Luddites"...now that is funny! I haven't heard that expression in years.

[Auzzee]

So named after a nut-case called Ned Lud who helped textle workers smash machinery at the start of the industrial revolution in England, because they thought technology would cost jobs. Now that could never happen, could it? I look at my telephone and think of the disturbed Ned every time an Indian bloke, who tells me he is called Steve or Barry (but never Patel) and claims to be calling from anywhere but Chennai, inquires into the state of my health and tries to sell me personal insurance, or a better cell phone deal.

[Trim50]

I once used "Luddite" as my radio handle when CB's where popular. No one understood the meaning and I was always having to explain...got old after a while. Good to see that there are a few out there with such insight.

[Gallivanters]

Trim,

Please... tell me more about your CoolBlue system. What is your box configuration? What sort of batteries? How are they re-charged?

The Technautics website makes them look attractive (as they ALL do)and I've inquired about what they can do for us.

We currently have two boxes w/ three holding plates and it sure would be nice if we can leave our plates as & where they are... but I hear they can't be satisfied with a 12 volt Waeco / Danfoss compressor.

Anyway - we installed a stern arch yesterday and can now mount our eight 80 watt solar panels. Now all I have do do is decide on which 12 volt fridge sysyem to commit to.

Have a great weekend,

Kirk

[Trim50]

The refrigeration that we replaced was a dual plate system that ran on AC and/or an engine driven compressor. It was 15 years old. Our freezer box is approximately 16ft^3 and the frig is approximately 32ft^3. It is a spill-over design.

We replaced both plates with a single 3.5” thick cool blue DC unit with the addition of a small DC circulation fan. We operate with approximately 1800Ahs from 8 house 6 volt batteries. At this time we recharge using our NextGen 3.5kW genset; however we plan to install solar before we go cruising. Nonetheless, if we run the Genset for an hour a day while making water and charging batteries, we have no problem keeping everything balanced. Solar would most likely eliminate the need to charge on a daily basis. The freezer stays at 5F while the fridge stays at 38-40F with the help of the circulation fan. The fan was key to being able to replace two plates with one. It is a simple DC computer fan that we installed at the top spill-over tube.

Also, when we installed the new system, we pulled the entire box out and replaced all the old insulation with aerogel vacuum insulation panels and injected Fomo insulation foam. This made an enormous difference.

The Cool Blue is a very simple system that you can install yourself. The owner of Technautics is an extremely friendly and helpful guy. He is a retired Ford Aerospace Cryogenics expert who started building refrigeration systems as a hobby…now he has a great little business. Give him a call and talk to him.

[Trim50]

Also, something that I found interesting is that the DC system at Technautics is actually an AC system with it's own inverter. Apparently this is the most efficient since an AC compressor is far more efficient, reliable and cost effective than a DC compressor. In addition, if you ever find yourself needing to replace a compressor 15 years from now off the coast of Africa, you can buy one at any hardware store.

Before I bought the Technautics system, I researched the cost of all the components from Grainger Industries and found that I couldn't build one myself for much less. Since he offers a 5 yr warranty, the dicision was easy.

[Auzzee]

Initially the system seems a little expensive. But if their claims about warranty returns and the five year warranty coverage are correct, it appears a good way to go.

[atavist]

Was digging around and came across this old thread... just wondering how the systems installed are holding up a year later?? Any changes you would make in retrospect?

J

[Gallivanters]

I ended-up installing two Danfoss BD-50 based units with digital thermostats. Both are air cooled by TWO computer fans on each condensor and power is supplied by the eight solar panels mentioned above feeding six Trojan 6 volt bateries.

I used a Waeco "forced air" evaporator in the freezer. The compressor is set to cut in at 14 deg f. and out at 7 deg f. and we can keep ice cream frozen when stored in the bottom of the box.

The fridge has an aluminum plate evaporator which I bent & mounted inside the box in a shape resembling the numeral 7. The compressor cuts in at 42 deg f and cuts out at 37 deg f.

I'm glad I went with digital controls and I can easily switch back to rotary thermostats should they ever fail.

The system works quite well in the tropics and has yet to need additional power input by either the battery charger or alternator in the six months since completing the installation.

Battery voltage rarely drops below 12.2 volts even while under the load of both compressors.

I'm totally happy with the results... and like to think of it as a Solar Powered Ice Maker.

To Life!

Kirk