New Refrigeration System Plan

[garymcg]

THe R-values for spaceloft (cryogel without the vapor barrier) are located here:

http://www.aerogel.com/Aspen_Aerogels_Spaceloft.pdf

The water absorption data for Cryogel Z is at the bottom of this document.

http://www.aerogel.com/products/pdf/Cryogel_Z_DS.pdf

[garymcg]

Originally Posted by senormechanico

Aerogel for insulation.
We're going to use Cryogel pretty soon.

Cryogel™ : Pacor Inc., Insulation Specialists

Those prices are about double of what Anchor Insulation charges. I paid $192 + shipping for 10 feet of 60" wide 10mm thick spaceloft; 5 feet of the same at Pacor is $225.

[senormechanico]

Thanks for the suggestion, I'll check them out.

[Richard Kollmann]

Skipmac’s Questions and My Opinion answers:

• Does the capacity of the system as planned seem adequate for the planned use?
  
  

Answer, An 8 cu ft combination box can not maintained desired temperatures efficiently with a BD 35 Danfoss compressor in operation below Latitude 40N.

Extruded Polystyrene (Blue Board) is moisture resistant but Polyurethane controlled density foam board has a 30% higher R value although a complete moisture barrier must surround it. There are insulation materials used in heating industry with higher R values but may not work well without needed air space be hind it for dehydration control in marine environments. Your insulation plan of R 20 around refrigerator is pretty much standard on new production boats. R 30 surrounding Freezer is a good idea especially if box size is reduced. Experimenting with other types of refrigeration insulation based on product claims is too risky. It takes several years of continuous use to determine value of these new insulation claims.

Always use the largest evaporator recommended for compressor condensing unit’s size.

As to system usage profile it looks good except 600 amp-hour may not be large enough without alternative energy sources you listed. Another item gaining popularity among cruisers is a 100 amp smart battery charger that can be connected to Honda 2000 generator for much quicker battery charging.

• Would the Frigoboat keel cooler be recommended in addition to or instead of the air cooled system. Frigoboat tells me the keel cooler and air cooled units can be installed in series and the fan turned for higher efficiency.

Answer, I would recommend the Frigoboat Capri 50 and Danfoss’s AEO control module. I do not recommend water cooling these small 12 volt Danfoss compressor systems.

• I have read that after 4" of insulation you start reaching diminishing returns. Would you agree or should I go for 5" or 6"

Answer, I ran a two week test comparing a highly rated GB VIP panel with an additional one inch blue board around a 4 cubic ft box and could not confirm it preformed any better than 4 inches of Polyurethane board insulation.

• I have read that after 4" of insulation you start reaching diminishing returns. Would you agree or should I go for 5" or 6"

Answer, Yes I agree that after insulation of 6 R value that it is hard to see a difference. I have heard it said the improvement in heat loss from 3 to 6 inches of insulation is as low as 15%.

• Any recommendations on the thermostat?

Answer, Gadgets are for pleasure party boats and not cruising boats. If it is not repairable, if it will not tolerate salt air and parts are not available locally, stay with standard dependable snap action manual thermostats that come with system you bought.

[Cheechako]

"However, your box is way too big. You could do with half that and be better pleased."

I agree with this unless you are just living aboard at a dock or marina hopping. In the third world it's much more difficult to keep a box full. I had a hard time keeping less than 3 cu ft replenished. The other thing is boat refrigeration is often less than perfect. It has cold spots and warm spots from poor circulation. If you put too many veggies in the refrig, you're gonna find alot of them go bad from frozen/cold spots etc.

[SV Demeter]

Originally Posted by Cheechako

"However, your box is way too big. You could do with half that and be better pleased."

I agree with this unless you are just living aboard at a dock or marina hopping. In the third world it's much more difficult to keep a box full. I had a hard time keeping less than 3 cu ft replenished. The other thing is boat refrigeration is often less than perfect. It has cold spots and warm spots from poor circulation. If you put too many veggies in the refrig, you're gonna find alot of them go bad from frozen/cold spots etc.

Were you cruising with a family of 4 or was it just you and the Admiral? I face a similar dilemma in my fridge rebuilt project for this winter. Theres no way my family of 4 would be happy with a 3cu ft box.

I have decided to rebuild the existing box (7 cf) with better insulation. Plan to build it strickly as a fridge with no freezer compartment. Will use a U or L shaped evaporator and most likley the Capri 35 air cooled. We then intend to purchase a Dometic CF-35

Products - Dometic

portable fridge/freezer that will serve as a separate standalone freezer. We figure that during most of our cruising we dont need a freezer as access to food is good so no need to freeze. Then on passages we will probably use the freezer. This also gives us flexibility in energy useage as when we are amps poor we can shut down the freezer. I originally planned a set up like the OP is suggesting but it quickly got complicated with the whole spill over door and space requirements. I also wast sure I could fit a big enough evaporator in a 1.5 CF freezer to handle the fridge loads of a 6-7CF fridge. Our current plan with the Dometic unit alows for a back up fridge too in the event the main fridge fails.

Our energy plan consists of 800ah battery bank. 400 watts of solar on articulating mounts controlled with Outback Flexmaxx 60, a 100 amp alternator, and we hope to add a wind genny although Honda EU2000 may be a better alternative (bang for buck) for when we cant make solar.

I am very interested in this cryogel aerogel stuff but am reluctant to use it for the very reasons Herr Kollmann mentions. No one has used this stuff in a marine fridge for any length of time. If anyone out there can talk to me about their results with this insualtion I am all ears.

Also can anyone speak to R-Parts? Im going to need a good icebox lid solution and was hoping to buy one of their prefab lid assemblies. Are they back in business?

[bene505]

Why do we tolerate leaky fridges and freezers (thermal-wise) anyway? It's a bit like keeping a leak in the hull and relying on the bilge pump to keep ahead of it. Go for every single bit of insulation you can get. It will pay for itself in the long run, #1) in less used amps (which take a lot of money/noise/space/maintenance/hassle to make and store), and #2 in less food spoilage when something goes wrong.

If you can fit the extra insulation, go for it. 15% less amps is wonderful.

Regards,
Brad
P.S. If I was designing something from scratch, I'd use a cryogenic container - think of a giant thermos bottle. Or 2 of them - one for fridge and one for freezer. Then I'd run the whole thing for a fraction of the amps.

[cat man do]

Originally Posted by bene505

P.S. If I was designing something from scratch, I'd use a cryogenic container - think of a giant thermos bottle. Or 2 of them - one for fridge and one for freezer. Then I'd run the whole thing for a fraction of the amps.

Like these?
CT Cryogenics Semen Tanks and Liquid Nitrogen Containers for Sale

[skipmac]

Thanks Richard, Very helpful but of course answers bring more questions.

Originally Posted by Richard Kollmann

Skipmac’s Questions and My Opinion answers:

• Does the capacity of the system as planned seem adequate for the planned use?

Answer, An 8 cu ft combination box can not maintained desired temperatures efficiently with a BD 35 Danfoss compressor in operation below Latitude 40N.

I did the calculations using an example on your slide show that seemed to indicate the BD35 might work but seemed marginal. As your web site recommended, I didn't want to go bigger than necessary but would certainly rather have a bit too much cooling capacity than not enough.

Originally Posted by Richard Kollmann

Extruded Polystyrene (Blue Board) is moisture resistant but Polyurethane controlled density foam board has a 30% higher R value although a complete moisture barrier must surround it. There are insulation materials used in heating industry with higher R values but may not work well without needed air space be hind it for dehydration control in marine environments. Your insulation plan of R 20 around refrigerator is pretty much standard on new production boats. R 30 surrounding Freezer is a good idea especially if box size is reduced. Experimenting with other types of refrigeration insulation based on product claims is too risky. It takes several years of continuous use to determine value of these new insulation claims.

I have seen specs on other types of insulation with better R-values but the potential for moisture absorption over time makes me a bit nervous. Your web site recommends 3-4 mil plastic around the insulation to stop this. How effective is this over 5-10 year period?

I'm concerned that in the construction process I may not get a perfect, all around seal or possibly make a small hole or rip in the final assembly. Would that over time allow polyurethane insulation to saturate or would a very small leak have only negligible effect?

Then, do you have any brand names or sources for the polyurethane? I tried to google it but found mostly technical papers and manufacturer's spec sheets. Since I'm in an area with limited resources I'm hoping to find something I can pick up at the local home store or building supplies warehouse.

Appreciate your position on experimental types of insulation. This is an area where I would not want to be a guinea pig as a failed experiment would result in tearing out the box to start over again.

Originally Posted by Richard Kollmann

Another item gaining popularity among cruisers is a 100 amp smart battery charger that can be connected to Honda 2000 generator for much quicker battery charging.

Forgot to put on my list that I will have two 75 amp multi-stage battery chargers.

Originally Posted by Richard Kollmann

Would the Frigoboat keel cooler be recommended in addition to or instead of the air cooled system. Frigoboat tells me the keel cooler and air cooled units can be installed in series and the fan turned for higher efficiency.

Answer, I would recommend the Frigoboat Capri 50 and Danfoss’s AEO control module. I do not recommend water cooling these small 12 volt Danfoss compressor systems.

Good. The keel cooler, though Frigoboat claims it is not an issue, seems to be a potential for galvanic corrosion and total system failure.

Frigoboat doesn't seem to offer the Danfoss AEO controller but does list the Merlin mini smart speed controller. Would that work as well or can I buy the Danfoss AEO elsewhere and use it with the Frigoboat system?

Originally Posted by Richard Kollmann

Answer, Gadgets are for pleasure party boats and not cruising boats. If it is not repairable, if it will not tolerate salt air and parts are not available locally, stay with standard dependable snap action manual thermostats that come with system you bought.

I take it that the fancy digital thermostats do not offer any significant advantage to justify the additional complexity and cost.

Again, thanks for the help.

[GordMay]

Originally Posted by skipmac

... So far I can find nowhere on the Aerogel website a spec on the R-value. The only statement I see is a claim of 2-8 times the thermal performance of the "competition" with no information on what they consider the competition...

... a typical aerogel insulation blanket has a thermal conductivity of 0.091 BTU-in/hr-sq.ft.-F at an ambient temperature of 32 degrees Fahrenheit, corresponding to an R-value of more than R-10 per inch...
➥ Ultra-Thin Super Insulation with Aerogel

[bartonman]

Originally Posted by skipmac

Dow blue board, about $25 for 4' x 8' x 2" (50 mm) thick. A fraction of the cost of the aerogel and a lot less work installing 4-6" in a box.

Max thickness I saw for the Aerogel was 10 mm ( less than 1/2").

So Aerogel for the same quantity of insulation will be 50-80 times more expensive than Dow polystyrene but totally would depend on how much Aerogel one would use to match the same R-value of Dow foam.

So far I can find nowhere on the Aerogel website a spec on the R-value. The only statement I see is a claim of 2-8 times the thermal performance of the "competition" with no information on what they consider the competition.

I also would like some information on the long term resistance to moisture absorption. If the stuff gets wet after a few years then it has pretty much lost its insulation value.

Generally I get very suspicious when a producer doesn't publish specs or data on their product.

Aerogel Spaceloft has an R-Value of 10 per inch. Though it comes in a maximum thickness of 10mm (0.4"), 3" will give you an R30 Value ( ASPEN AEROGELS | Building & Construction Insulation ). Where as the Blueboard would require approx 6" to get R30 value. So space vs. cost is the battle. Aerogel is hydrophobic, so it will not absorb water. Spaceloft will not loose its insulation value, even under compression. Aspen has been creating industry specific marketable types of Aerogel mat. I guess, so they have more than one product to sell. When NASA helped them develope the usable version of Aerogel mat, it was basically all purpose. Now they appear to be refining the ingredients and manipulating the capabilities of each model, or are they. However, Aerogel is Aerogel and the insulating property of it, is what it is, no matter what color you make it. I am certainly a fan of the material touted as the best insulation on the market today. I have done extensive research on it prior to purchasing a large quanity of Spaceloft. I am going to be installing it on my boat in every way I can.

[robert sailor]

When your installing this new insulation, can you simply butt it together in areas that are being insulated??? I'm working on a fridge project right now and would appreciate any feedback, thanks