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FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2005 - 10:18 am: | |
There are many differences between the refrigeration needs of the cruising boaters , and the bus campers, mostly the availability of power.
While at the Power Post a constant cycling house takeout will easily work for the camper , and as well for the boats large enough to accept a house sized fridge.
Underway or boondockin refrigeration is the bigger hassle.
The bus folks usually select propane for extended camping , but the location of most fridges inside the boat removes that opportunity for SILENT,simple and cheap cold food.
The boat folks ARE easily convinced of what the "off grid" folks have been preaching for years ,
a dollar spent NOT needing power is worth $5.00 in generating and storing power savings.
First the boaters are usually willing to construct a really efficient box for fridge & freezer.
Most common is 4 in of insulation on the fridge side and at least 6 in on the freezer.
The custom boxes used to be mostly top opening , but today many are front opening as the food retrieval is faster.
For cooling there are many common methods.
1.With a huge battery bank and lots of gen set time an inverter and house fridge can be made to work.
2.Better for the folks with lots of daily genset time is an AC + holdover system.
Here a cold plate (eutectic plate) is frozen as much as available power will allow , and the unit should hold all night , during genset Quiet Times.
3 For the real cruisers a compressor is driven from the main engine or genset by belt to feed 2 or more holding plates.
This is a very powerful setup and usually only needs an hour a day of engine time.
4. The latest in DC cooling will either use std evaporator plates or feed cold plates.
Danfoss offers the DB 35 and DB 50 compressors with an option called Adaptive Energy Optimization (AOE)
that can vary the speed of the compressor to the load and reduce energy use dramatically , compared to the older single speed units.
Frigiboat Smart Speed Controller (SSC) is similar and attempts to run the compressor 50 min an hour at the slowest speed.
The slower speeds uses less electric and is more efficient.
The Frigiboat has an added advantage of switching ON at full speed any time the V is over 13.2 (for 12V systems) so any engine time or other source of power goes as rapidly as possible into the fridge.
Danfloss, 410.931.8250
Frigoboat www.frigoboat.com
Glacier Bay (great site) www.glacierbay.com
Isotherm www.isotherm.com
Norcold www.norcold.com
Technautics www.technautics.com
Sea Frost www.seafrost.com
Waeco Usa
www.waeco.com and www.waecousa.com
I dont think that even 5 of the 5000 bus RV campers will ever actually build a super efficient box and go to the trouble of a real marine style unit (since propane works so great) However someone asked, for marine style info.
FAST FRED |
Edward J. Sommers (Sommersed)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2005 - 11:16 am: | |
Before I decided to start RV'ing, I spent years investigating and/or planning on a remote, off-the-grid retirement.
Part of that plan was to make my own 12/24 volt, highly efficient, frig with an available kit.
The kit is harder to find nowdays due to the efficiency of off the shelf units, but which can be brought even more efficient with the addition of hard foam panel to the sides and front.
For examples of these units go to a good solar site. I like backwoodssolar.com myself.
No, I'm not affilitated, and I use propane as I boondock 10 to 11 months/year.
Ed
1967 MCI5A
Fulltiming |
Jim (Jim_in_california)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2005 - 4:21 pm: | |
Well here's something quite interesting:
http://www.go-rv.com/coast/do/catalog/page?dealerId=333&pageNum=292&productId=65324
If you punch in the part numbers, you see that the bigger (53quart) version ($519) is just about the same price as the 33quart variant ($525) - I assume the smaller is better insulated or something.
In any case, these are Danfoss-based DC variable compressors and they can be a fridge or a freezer as they're "settable" between 5degF and 51degF.
A pair of these would be less than most of the Danfoss-based vertical combo units. You'd also have a lot of flexibility and reduncancy in case of failure of one. |
joe padberg (Joemc7ab)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 13, 2005 - 10:23 pm: | |
Thank you FRED for digging up those links. I especally appreciated the essay found on the glacier bay site regarding the transmission of heat between various materials. I have sceptical regarding some claims made by some commercial products in the market place. I am not yet at the stage of coach insulation, but am very much looking at the options that I have for insulating the busbarn. Wasconsiderg the use of standard pink fibreglass, but when pricing it out, the cost for the ceiling alone is almost a grand to insulate to R36. BTW it is cold here in winter at times, even though most of our nat gas is exported south we pay almost as high a price as our southern neighbours. tnx to nafta. I think I will go with the traditional that was commonly used 30 years ago Wood shavings. R value is .8 times value of fibreglas but the cost is only 180 Canpesos to get the equivalent insulation level.Will have to conscript the kids one Saterday for payback time. I framed the walls with 2x6's so that will likely end up with batts. Joe |
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