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#11
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I guess that depends upon the lid configuration and how often it
is opened. I have a Coleman Extreme and find the ice lasts alot longer if you drain off the excess water. Perhaps leaving a little in bottom is a good idea. I tend to rely on the laws of physics rather than ad hype from vendors. Doug s/v Callista "Glenn Ashmore" wrote in message news:ZvqTc.28303$Jo1.5448@lakeread01... I used to think that but the Coleman cooler people did a lot of research on this controversy. The new Xtreme coole I bought for the trip came with a little booklet about how to stock a cooler. They are saying that as long as there is a little ice remaining before restocking to leave the water in the box. The other thing is that water does not escape when the lid is opened the way cold air will so the total heat gain will be less. BTW, the new Coleman Ultra Xtreme coolers do work. We used about 2/3rds the ice this year over 10 days in the BVI as we did last year in a week. As to whether they keep ice for 7 days as advertised, maybe in Minnesota but not in the Virgin Islands. :-) Doug Dotson wrote: If cooling the drinks fast is your goal thaen this approach will work. But once the ice has melted, then the refrigeration will be working much harder than usual to keep both the drinks and the large volume of water cold. Better to turn on the fridge, add the drinks and ice but let the water drain off as it melts. Doug s/v Callista -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#12
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I would not keep it completely full of melt and by making it relatively
narrow fore and aft the level can still be fairly high without spilling. auerbach wrote: Glenn, You say "It will need foot rests to keep braced in the seats on a heel." Won't melt-water in your cooler spill out on when your boat heels? Alex -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#13
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Doug Dotson wrote: I guess that depends upon the lid configuration and how often it is opened. I have a Coleman Extreme and find the ice lasts alot longer if you drain off the excess water. Perhaps leaving a little in bottom is a good idea. I tend to rely on the laws of physics rather than ad hype from vendors. Doug s/v Callista Coleman isn't the only source of that information. Hormel provides a camping tips booklet that says the same thing as did an article last year in Trailer Sailor. There is definitely some good physics behind the principle. As long as the water is close to the target temperature of the box, there are several advantages over a dry box, especially when the box is refrigerated. Basically the heat enters the box by adding warm drinks, allowing warm air in when the box is opened or through the outer surfaces. There is not much you can do about adding warm drinks except cut back on the beer consumption but by reducing the amount of warm air that can get in heat gained due to opening can be minimized. The speed heat comes through the sides is directly related to the difference between the inside surface of the box and the outside. It does not matter if the box is full of water or air. As long as the difference in temperature is the same. The evaporator coils are close to the inside surface and will operate at a temperature about 10-15º below the target temperature of the box. Water transfers the heat from warm drinks to the coils faster than air so the temperature is more even all over the box. If there is no water move the heat quickly the inside surfaces next to the coils will get much colder which increases the rate that the heat will come through the sides. The compressor WILL run longer with the box full of water to cool the box the same amount but it will run less often once it reaches the target temperature. Net result is an overall energy savings. Here is a pretty good explination using ice only but the effects described are magnified with a refrigerated box: http://www.madsci.org/posts/archives...3228.Ph.r.html -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#14
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Glenn, here's a solution complicated enough to appeal to you ;-):
Let the cold box drain into another insulated tank/box whose function is to pre-chill warm beers. You could get every last BTU out of that ice before it's drained. Don't some air heat exchangers work this way? |
#15
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Interesting. I'll have to read up on this some more. I suppose the same
principle won't work well in the freezer box Doug s/v Callista "Glenn Ashmore" wrote in message news:JVvTc.28578$Jo1.27533@lakeread01... Doug Dotson wrote: I guess that depends upon the lid configuration and how often it is opened. I have a Coleman Extreme and find the ice lasts alot longer if you drain off the excess water. Perhaps leaving a little in bottom is a good idea. I tend to rely on the laws of physics rather than ad hype from vendors. Doug s/v Callista Coleman isn't the only source of that information. Hormel provides a camping tips booklet that says the same thing as did an article last year in Trailer Sailor. There is definitely some good physics behind the principle. As long as the water is close to the target temperature of the box, there are several advantages over a dry box, especially when the box is refrigerated. Basically the heat enters the box by adding warm drinks, allowing warm air in when the box is opened or through the outer surfaces. There is not much you can do about adding warm drinks except cut back on the beer consumption but by reducing the amount of warm air that can get in heat gained due to opening can be minimized. The speed heat comes through the sides is directly related to the difference between the inside surface of the box and the outside. It does not matter if the box is full of water or air. As long as the difference in temperature is the same. The evaporator coils are close to the inside surface and will operate at a temperature about 10-15º below the target temperature of the box. Water transfers the heat from warm drinks to the coils faster than air so the temperature is more even all over the box. If there is no water move the heat quickly the inside surfaces next to the coils will get much colder which increases the rate that the heat will come through the sides. The compressor WILL run longer with the box full of water to cool the box the same amount but it will run less often once it reaches the target temperature. Net result is an overall energy savings. Here is a pretty good explination using ice only but the effects described are magnified with a refrigerated box: http://www.madsci.org/posts/archives...3228.Ph.r.html -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#16
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Jim,
Really like that solution for ice boxes. Have always hated to discard ice cold water, and prechilling the beer will certainly help out ice life. All those who stayed awake during high-school physics will recognize that adding 4 cans of beer to an ice box will result in the melting of a beer can sized block of ice - even without any heat transmission through the walls or floor of the box. Cool your beer first, and you might be able to put a dozen in for the same ice use. Thats energy conservation where it counts! surfnturf "Jim Conlin" wrote in message ... Glenn, here's a solution complicated enough to appeal to you ;-): Let the cold box drain into another insulated tank/box whose function is to pre-chill warm beers. You could get every last BTU out of that ice before it's drained. Don't some air heat exchangers work this way? |
#17
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Another option would be the kiss aproach.
Maybe build a nice combing that is sized to contain an ice chest. You can buy a big cheap one like the 120 igloo that sells at sam's for under $40 or you could go for a really nice expensive ice chest, like the Icey-Tek, www.icey-tek.com . Friends tell me these are great.( I like the big and cheap). If you really hate using ice, you could put a 12V power plug in the combing and use a thermoelectric cooler, Igoo , Coleman ect . -- Ron White Boat building web address is www.concentric.net/~knotreel |
#18
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Glen, there are three proven way to build the system you are looking
for: 1. Install a full length stainless steel holding plate in an insulated box, it can be used as a dry box or a wet box. See picture on front page of my web site, this box's holding plate is connected to a Danfoss BD2.5 compressor. The purpose of the plate in this cooler is to act as a flywheel affect of energy when warm product is put in the box. 2. The same insulated box can be cooled by a plain copper tube coil attached to interior wall. When I did fish hold box designs I used stainless tubing with tubing above and below the water. 3. Either one of the above concepts can be used with an existing large refrigeration system by splitting the refrigerant flow. I have system #1 in one of my boats and system #3 in the other. Glen here is a concept using a Danfoss BD50 air cooled condensing unit, and 50 ft. of ¼ inch tubing as an evaporator coil, A receiver and expansion valve instead of a capillary tube. This combination in a drink cooler with a 30 degree evaporator temperature might deliver 790 btu. Per hour. ( Danfoss ASHRAE Capacity chart with compressor running at 3500 rpm ). I would also install a manual speed selector switch to adjust compressor speed for current box demand. From the author of books on boat refrigeration http://www.kollmann-marine.com Glenn Ashmore wrote in message news:07aTc.27910$Jo1.1742@lakeread01... On our recent BVI cruise I started thinking about cockpit drink coolers. The beneteau 505 has a very poorly insulated cooler in the cockpit table that is a total waste of ice. RUTU, being derived from a modern high performance design, has a very wide fairly shallow cockpit. It will need foot rests to keep braced in the seats on a heel. I am thinking about building a perminent heavily insulated box down the center. It could also be used as a seat at anchor when the table is folded up and the cushion would serve as additional insulation. Now the question is how to keep it cold. I am thinking that a small evaporator type system would work. Drinks cool fastest in water so stocking originally with drinks and ice would provide the water. Once the ice melts the evaporator would maintain the temperature and the water would serve as a heat sink. What I am worried about is that the aluminum evaporator would corrode rather quickly constantly submerged in water. I am wondering if several loops of copper tube might make a better evaporator. |
#19
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#2 is the idea I am leaning towards. I have room to mount an air cooled
BD50 directly below the box with plenty of ventilation. Couple of things still have me stalled. I would like to use .192" ID stainless tube which should stand up better to bumps with cans and corrosion but the thermal conductivity is a lot lower than copper. I could compensate by going to .335" ID but that might slow down the refrigerant to much to push the oil through. Think I will stick with ..192" and adjust the expansion valve and compressor speed. The other thing is probably that I am not reading the charts right but I can't figure out which orifice to use in the Danfoss expansion valve. They all look to large for the BD50. BTW, have you revised the DIY book? I have about worn my copy and the Calder book out. :-) Richard Kollmann wrote: Glen, there are three proven way to build the system you are looking for: 1. Install a full length stainless steel holding plate in an insulated box, it can be used as a dry box or a wet box. See picture on front page of my web site, this box's holding plate is connected to a Danfoss BD2.5 compressor. The purpose of the plate in this cooler is to act as a flywheel affect of energy when warm product is put in the box. 2. The same insulated box can be cooled by a plain copper tube coil attached to interior wall. When I did fish hold box designs I used stainless tubing with tubing above and below the water. 3. Either one of the above concepts can be used with an existing large refrigeration system by splitting the refrigerant flow. I have system #1 in one of my boats and system #3 in the other. Glen here is a concept using a Danfoss BD50 air cooled condensing unit, and 50 ft. of ¼ inch tubing as an evaporator coil, A receiver and expansion valve instead of a capillary tube. This combination in a drink cooler with a 30 degree evaporator temperature might deliver 790 btu. Per hour. ( Danfoss ASHRAE Capacity chart with compressor running at 3500 rpm ). I would also install a manual speed selector switch to adjust compressor speed for current box demand. From the author of books on boat refrigeration http://www.kollmann-marine.com -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
#20
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Refrigeration tubing is measured in OD and ¼ OD is .192 in. ID. Many
home built systems make the mistake of using tubing that is too large in their systems. All refrigeration compressors require a return suction gas temperature of from 60 to 90 degrees F. for compressor cooling. Compressors also rely on a reasonable gas velocity through the system to return the oil. You could get by with 5/16 OD tubing, but I would not run the system set to a very low temperatures. You are correct about tube damage in the box, there must be some type of a guard to protect it. I ounce did a system for a crab fisherman in Alaska and he put a live fish inside that punch a hole in the refrigerant tubing. When you want variable capacity with the BD50 in the case of your purposed system I would use a OX Danfoss orifice. Yes, I know the OX is a 1500 btu orifice but as soon as it sees the cool return gas it will adjust down. You should have my latest Do It Yourself Book revised in 2000. And the book you just ordered 12/24 volt Refrigeration Manual covers changes in DC refrigeration up to 2004. I believed that revising the original book every five years was good enough. Today with the changes in the industry and the high cost of service I felt I should find another way to communicate more often than five years. Book revisions, service bulletins and typical repairs would cost too much so I elected to use my web site as a way that book owners and others can keep up to date with what is new in boat refrigeration. Glen if you don't find all you need in the design section of the new book please use the new refrigeration forum on my web site to ask your questions. http://www.kollmann-marine.com. Glenn Ashmore wrote in message news:vW5Uc.29891$Jo1.23863@lakeread01... #2 is the idea I am leaning towards. I have room to mount an air cooled BD50 directly below the box with plenty of ventilation. Couple of things still have me stalled. I would like to use .192" ID stainless tube which should stand up better to bumps with cans and corrosion but the thermal conductivity is a lot lower than copper. I could compensate by going to .335" ID but that might slow down the refrigerant to much to push the oil through. Think I will stick with .192" and adjust the expansion valve and compressor speed. The other thing is probably that I am not reading the charts right but I can't figure out which orifice to use in the Danfoss expansion valve. They all look to large for the BD50. BTW, have you revised the DIY book? I have about worn my copy and the Calder book out. :-) Richard Kollmann wrote: Glen, there are three proven way to build the system you are looking for: 1. Install a full length stainless steel holding plate in an insulated box, it can be used as a dry box or a wet box. See picture on front page of my web site, this box's holding plate is connected to a Danfoss BD2.5 compressor. The purpose of the plate in this cooler is to act as a flywheel affect of energy when warm product is put in the box. 2. The same insulated box can be cooled by a plain copper tube coil attached to interior wall. When I did fish hold box designs I used stainless tubing with tubing above and below the water. 3. Either one of the above concepts can be used with an existing large refrigeration system by splitting the refrigerant flow. I have system #1 in one of my boats and system #3 in the other. Glen here is a concept using a Danfoss BD50 air cooled condensing unit, and 50 ft. of ¼ inch tubing as an evaporator coil, A receiver and expansion valve instead of a capillary tube. This combination in a drink cooler with a 30 degree evaporator temperature might deliver 790 btu. Per hour. ( Danfoss ASHRAE Capacity chart with compressor running at 3500 rpm ). I would also install a manual speed selector switch to adjust compressor speed for current box demand. From the author of books on boat refrigeration http://www.kollmann-marine.com |
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