H34 - What Type Of Refrigeration Do You Have?

[Joe Mullee]

I want to add refrigeration to my 1983 Hunter 34. Just tired of hauling ice. I've done some homework and because of price, ease of installation, and needed efficiency I'm thinking of an air cooled system for my 6 cubic foot ice box. If anyone has any insight into any of my questions I would appreciate any advice.

If you have an H34 with refrigeration did you have to add more insulation? If so what type did you use and how did you do it?

My house bank is 291 amps. My main energy draws are Raymarine ST60 depth finder and a Raymarine Smart Pilot. I'm very carefull with my DC power usage and over the winter replaced all lights, both interior & exterior with LED's. A few of the refrigeration systems I've looked at average less then 25 amps per day. I have a Yanmar 3GMF with the standard 35 amp altenator. Any advice on my power setup?

I'm looking primarily for a refirgerator and not neccassarily a freezer. I sail on the Chesapeake where I believe the summer time water temps reach the mid to high 70's F and the average summer air temps are between 85-95 F. I day sail every week and do an overnighter once or twice a month. I also take a 5-7 day trip twice per year. This year maybe I'll get that 2-3 week trip in.

So what advice can you give me? What type system do you think is best? Thanks in advance for any information you can share.

Joe Mullee

 

[Steve Dion]

Joe:

There was a recent post on this subject. These unit will only lower the box temp by 40 deg. based on the ambient air temp.

When you consider the energy draw you will probably need to add MORE batteries to your bank you are bettery off with a traditional cooling unit.

We ended up getting a Isotherm SP unit. It cools the coolant thru the sink discharge through hull fitting. Easy to install and very easy on the power consumption.

 

[Roy Page]

My 1983 Hunter 34 has a Norcold unit fitted in the ice box without additional insulation.
In the dock it runs off 110v shore power and switches automatically to 12v when shore power is disconnected.
The unit is a Norcold SCQT4407.
The compressor is under the cockpit rear lazerette and it is fed with a second pair of batteries charged by a Blueseas battery combiner.

Halfway through the season, I have needed to defrost it to keep the accumulated frost in check, so you know it is a very capable unit.

My beer is always very cold

 

[kloudie1]

When I bought my boat back in '91, it had an old (my estimate, '87 model) FROST FM-2.5 water cooled 12V unit. The battery bank was 200 amp hours (6V golf cart batts) .. The evaporator was a vertically mounted unit that had ice trays in it. Worked very well with the standard insulation in the box. A seal was added to the lid at the inside edge. The installer had installed the evaporator on the engine side wall inside the box and the engine vibrations caused the ice trays to wear a hole through the pressed evaporator, causing loss of refrigerant. I attempted repairs, but none would hold.. I have the unit in the garage here .. have not bought a new evaporator for repair, but that is on the list.. (??) The unit always worked very well until the Freon 12 leaked out. I have a buddy with an air cooled unit and it uses a little more power than the water cooled ones. It also heats the cabin from the condenser heat. It must be very well vented in hotter climates, but it works.

 

[Joe Mullee]

Conversion vs Stand Alone

Steve,

My understanding is that the conversion units will allow the existing ice box to run like a refrigerator/freezer. It's a permanaent installation. Some of the manufacturers I'm considering are Alder Barbour, Frigoboat, Norcold, & Sea Frost. I think what you're referring to (40 degree's below ambient temp) are the stand alone units that are shaped like an ice chest and are portable. I know Engel & Norcold sells them as well as others.

I will take a look at the type of set up you have as well.

Thanks,
Joe

 

[kloudie1]

Those that can only do 40 F under ambient are solid state devices .. thermoelectronic or "Peltier Effect" coolers.. The ones that Joe is talking about have compressors like a home fridge.. Some have air cooled condensers, like a home fridge, and some have water cooled condensers to make the compressor's job a little easier and make them more efficient with power use..

 

[Ed Schenck]

Here is a link to my simple A/B installation: http://hunter.sailboatowners.com/in...&cat_id=38&aid=7309&page=article&mn=37-cutter .

Just noticed the post is not dated. Did that in 2001 I think. Has peformed flawlessly.

 

[Bill1565]

I've had Adler Barbours on 3 boats. No problems. Energy use depended on isulation. Units draw 5-6 amps when running. Run 25 to 50 % of the time .

 

[Steve Dion]

Joe: Okay! When you mentioned Air Cooled, I assumed (big mistake) that you were referring to one of the thermoelectric models.

The reason I was mention the Isotherm SP units was a friend of mine was able to run his refrigeration unit during the summer while moored on a mooring with just solar panels. This was on a Hunter 33 (Cherubini).

One of the big advantages of these units is the fact that the coolant runs through a hull fitting and there is virtually no heat or noise generated by these units. They are moderately priced and use quality parts.

http://www.emarineinc.com/categories/Refrigeration/Ref{47}Frez-Build%2dIn-Isotherm/

 

[Dan Johnson]

Joe...

I've been considering a Honda 2000 to power my dorm-style fridge that replaced the oven portion of my stove and support my thermo-electric cooler. Almost a dollar trade-off. Has other power source advantages as well.

From the boat business service experience, stay with A/B or Norcold.

Nice job in going all LED! Something to consider. Don't forget that the VHF and any tunes machine will draw at least 2 amps each too.

 

[Paul and Judy]

I am seriously considering installing the Isotherm ASP, SP unit that releases the heat from the ice chest via a coil in the galley sink seacock. Following is some information on the unit.

The Water Cooled, Self Pumping (SP**) ASU (Automatic Start Up*) Model 3751 Refrigeration System can cool as a refrigerator or as a freezer. The maximum freezer capacity is 2.3 Cubic Feet and the maximum refrigerator capacity is 7.1 cubic feet. This model is cooled directly by the surrounding water because it includes a Self-Pumping, Sea Water Pump that eliminates the fan and electric pump for quiet operation and offers very low power consumption. Isotherm's ASU Models are equipped with the optional, patented Automatic Start Up System that senses when surplus power is available and stores refrigeration energy in holding plates mounted near freezer compartment. The ASU system can dramatically reduce the drain on your battery.
* Isotherm ASU Systems are designed for installations in existing cool boxes and mainly for use in sailing yachts where battery power is at a premium. The ASU system dramatically reduces power consumption while supplying refrigeration in abundance. It senses when surplus power is available from the engine alternator and speeds up the compressor to rapidly freeze the holding plate. When surplus power is no longer available it reduces its energy-use accordingly. The stainless-steel holding plate can be fitted at any suitable angel high up in the box before being connected to the compressor unit by the three meter long six mm diameter flexible copper piping fitted with quick-couplings. The compressor unit is small enough to be fitted in a stowage within connecting distance from the holding plate. Extremely quiet when running, it can even be fitted under a bunk if needed. After connecting the leads to the battery, the pre-filled system is ready to go.
Sea Water Cooled (SP) Features:

• Fridge or Freezer use
• Sea Water-Cooled / Self Pumping
• Patented SP System eliminates the fan and electric pump for quiet operation and very low power consumption.
• 12/24 Volt DC Danfross Compressor
• Easy installation with pre-charged system, "Click-on" bracket and quick connect lines

Specifications
Isotherm ASU 3751Type

3751​

Max Box Volume cu.ft.

7.1​

Evaporator

Medium holding plate​

Dimensions evaporator
A x B x C inches

14x11x2.38​

Dimensions compressor
L x W x H inches

8.25x5.31x6.13​

Power Consumption (Amp)
Average A/hour/
Max by 12 V

0.55/6.0​

Weight (lbs.)

37​

Danfoss Compressor Model

BD50F​

Temp Range

Fridge​

** Sea Water-Cooled / Self Pumping: The Isotherm SP unit is a totally new system that is cooled directly by the surrounding water. This means that refrigeration efficiency is completely independent of the air temperature inside the boat. Even on the hottest days of summer - just when a refrigerator is needed most - the sea water cooled Isotherm SP operates consistently at an extremely high level of efficiency insensitive to high ambient temperatures. It also consumes much less battery power as no fans or pumps are required to dissipate the heat generated by the refrigeration compressor.
Self Pumping Features:

• Sea water cooling for even higher efficiency
• Heat removed by water means cooler boat
• This means that warm water is continuously pumped out and cold water in, movement which also prevents fouling.
• Lower power consumption.
• Silent - no fans or pumps
• No extra holes required in hull and nothing protrudes.
• Simple to fit
• The included through-hull fitting is of salt-water resistant brass and the full-flow coil heat exchanger is of copper-nickel alloy
  • Replaces the through-hull fitting for galley sink
  • The one meter long pipe connecting it to the compressor and the 3 meter one from the cold-holding plate are both prefilled and fitted with quick-fit connectors.
• A zinc anode comes with the kit

Although heat always rises if left to the laws of nature, the Isotherm SP unit leads the heat downwards and out through the boat's hull by utilising the natural pumping action inside the hull fitting for the galley sink drain hose. As this hose is not restricted by pumps or non-return valves, the flow inside is completely free. Each movement of the water surrounding the boat reproduces a similar change of the water level inside the hose resulting in the pumping of a similar quantity of water in and out through the hull fitting.
By designing a special hull fitting containing a non-restricting, full-flow spiral heat exchanger for cooling the heated refrigeration agent, an extremely efficient cooling system is created.
As the hull fitting is always situated some distance from the boat's centre of gravity, even the smallest movement of the hull or mast of a sailing boat is sufficient to create a pumping action even in the calmest of waters.

 

[Steve Dion]

P & J:

I have an Isotherm SP and have been extremely pleased with it. I actually purchased this unit with input from Steve Weinstein. He has one on his Cherubini H33. It was on a mooring and he was able to keep his batteries charged with just solar panels and perodic engine charging.

I really like the unit. It does not discharge much heat to the interior of the boat is nearly silent.

We went with an evaporator plate instead of a holding plate but I do not think that there is much different in power consumption. I believe that we purchased a model SP 2553. I do not think you will be disappointed .

 

[Joe Mullee]

Hey Steve Dion,

Can you give us an idea of the average amps per day your system uses? I do like how your system works but am interesred in the power requirements.One of the units I'm looking at is Frigoboat Capri 35F. They were written up in Practical Sailor in June 2009 and compared with Alder Barbour Cold Machine (CU 100) and the Sea Frost BD. The main reason I like them is they are an air cooled system (easily installed) and they advertise that their average daily consumption is 22 amps for a 6 cf ice box to refrigerator conversion. I've seen nothing that low. Practical Sailor gave them the nod compared to the other two (though they said all were good systems) and did not dispute their 22 amp per day claim.

I'm curious what other sytems require when it comes to their amps daily draw. I'm willing to pay a little more as you have for a system that will work best with my boat.

Let me know.

Joe Mullee

 

[Steve Dion]

Joe:

I really do not have the actual power consumption. If you look at the Isotherm website they have some stats, but like any unit it depends on the ambient air temp, insulation etc. The Cool Blue units are also rated as very low consumption, but the amount of energy is based on all the above, if you have a good seal around the lid, how much you open the box etc. These things are all going to effect how well the units function.

 

[Brad Hoff]

I put on a Sea Freeze unit about 3 years ago and am very happy with it. It only runs off of 12v but my shorepower battery charger handles it fine. It comes with the icebox evaporator, which makes ice fine and will keep ice cream, although it is somewhat soft. All other food items seem to stay frozen ok. Main box stays steady at 43 degrees F year round as the unit is always on. I did not add any insulation yet and may do it this summer. Runs about 30-40% of the time during warmer weather. I put the compressor unit in the far starboard corner of the rear cockpit locker. The lines that came with the unit fit perfectly from the icebox running along the hull to the rear corner. Easy run for electrical from the panel, although I had to add a subpanel with more breakers. I like having the unit exposed to the ambient temperatures. If it gets really hot in the summer, I open up the cockpit seat to let in more air circulation. Having the compressor in this outside area also seems to keep the locker dryer. Complete installation took about 1/2 day. I do hear a little noise when the unit turns on because I usually sleep in the rear berth. I've gotten use to it and actually like knowing how much the unit is really running. I put in the SF-910 unit. Looks like prices have risen from when I installed my unit.

http://www.seafreezeinc.com/price.shtml

 

[Brad Hoff]

I need to correct my last post. The compressor is on the far port corner, not the starboard. Sometimes I don't know my right from my left!