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Could I get a "radio" check out of anyone?? over. Pages: 12

LJG on Sun February 15, 2004 4:19 PM User is offline

Country of Origin: United States

Yeah - so - anyway, new guy here, I've got a project, I need to build a new Ref. system and have lots of questions. I'm Kindof a gear head gone Commercial fisherman. I have a commercial fishing vessel in Alaska that is 32'x15' It is powered by three port fuel injected marine 454's coupled to three 10' Kodiak jet water pumps. The boat needs a refrigeration system and I am looking at A6 compressors and custom to the vesel chiller tubes (condensor and evaporator). Anyone interested in thinking outside the box????

TRB on Sun February 15, 2004 5:49 PM User is offlineView users profile

Do you have any specific questions?

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MrBillPro on Sun February 15, 2004 5:49 PM User is offlineView users profile

I have a buddy has the same size boat and we just split up a large window unit installed the evaporator section in the cabin "he built a special cabinet to install it in" and ran copper to the back of the boat from the evap. to the condensing part we also installed the condensing part close to some port holes with the condenser turned up and the discharge air is vented up through a grille in the floor in the rear of the boat. The unit is cycled off and on through a digital thermostat hooked up to a 220/24 volt transformer tied in to a regular double pole double throw 24 volt a/c contactor, and of course all this is powered by his 6000 watt 110/220 volt generator this setup has served him well and may give you some ideas if nothing else to get you starter.

I your trying to build a refer. your not going to do it with a a6 powered compressor running off you engines to much variation in temps you would be better off getting you a generator and buying you a big freezer, but then again i am not really sure of what your trying to do.
Take Care Mr. Bill

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Don't take life seriously... Its not permanent.

Edited: Sun February 15, 2004 at 5:54 PM by MrBillPro

NickD on Sun February 15, 2004 8:35 PM User is offline

LOL, maybe instead of thinking outside of the box, we should be thinking about inside the boat. Saw a Discovery show on Alaskan fishing, some of the meanest waters in the ocean so those guys say. What do you fish for? Do you really need a cooler in Alaska? How many cubic feet in your chiller, the peak ambient, the projected BTU loss, and what temperature do you want to maintain on the interior.

LOL, how long of an extension cord do you have, well you said to think outside of the box.

LJG on Mon February 16, 2004 1:13 AM User is offline

So I have had just enough engineering to be dangerous. Went through a GM sponsored ASEP progam about ten years ago and worked in the dealership for a few years to follow, I had ASE master certs at one time auto and medium/hevy duty truck. Ive spent the last while building and designing commercial fishing boats in my 10 month off season to my focus which is commercial salmon gillnetting in Bristol Bay.
Anyway there are places that sell RSW systems for about a bizzilion dollars. They come as modular units that are either hydraulic driven or diesel (small, 25 horse) driven. neither of theese I like. can anyone say HEAVY, BULKY, EXPENSIVE, But other fishermen buy them and are happy to have something that will do the job.
AN analogy : I think this would be like pruchasing a large portable boom box, or no wait beter yet, a home stereo then Placing it wherever it will fit - In your passenger seat - and runing the whole thing off a 12V to 120V power converter plugged into the cigarett lighter.
Dont get me wrong that will work --- Re-freaking-tarded. This is how I feel the marine industry has approached the refrigeration issue.
lets start with what little I do know. A 5 to7 ton system is adequet. Weight is critical. The boat runs in water about 45 degrees. The fish can come at up to 4000lbs an hour, but usually closer to 1000 lbs an hour. The fish are 45 degrees.
I have marine 454's. i could probably find bracketry stock to an old truck or somethin that will support an A6 compressor like it came stock. My bottom plate (Hull Skin) extends past the transom about 16 ", giving a nice protected place to install a grid of serpentine like bent stainless tube (high side - after compressor, before orafice valve/tube) "condensor". normally this is done on a boat by a chiller tube where sea water is pumped thru a heat exchanger to take the heat out of the "high side". The fish are put into bins that have some water added to them then the water is circulated thru a second chiller tube (another heat exchanger or evaporater) this low side heat exchanger cools the fish hole water which in turn cools the fish. I think that the fish need to be chilled to 36 degrees, to make grade for a higher pay scale. The fish hole water is sprayed onto the fish from spray rails (pipe with holes drilled in it), these spray rails are located arround the top perimeter of the fish bins. The bins have a suction in the bottom, water makes its way to the suction and then is pumped (recirculated over and over) through the low side heat exchanger and back to the fish.

If you are not convinced I am completely mad yet, lets go deeper into the "rabbit hole"
Now Imagine that the low side heat exchanger was stretched out in lenght, but maintaining the same heat exchanging capacity, stretched to the point that the thing was nothing more than a tube (low side reffrigerant line) inside another tube (circulating fish hole water). As long as it has the propper heat exchange capacity, and volumetric capacity, its shape is nearly irrelavant. So rather than having a chiller bottle and spray rails and plumbing between - cost, weight, effort, occupied realestate I suggest -----building custom chiller spray rails . yup wrap the evaporator arround the top oppening of the fish hole and encapsulated it in a larger diameter pipe in which the fishhole water is circulated. this seems to make great sense to me, where the cold is brought to the air stream.
The same with the condensor, why bring the cold to the condensor when you can bring the high side (condensor) to the cold. Like what has been done with nearly every auto on earth.

What I dont know : How does a person find out any sort of ratting on an A6? I need something to do my thermal calculations to find out how many linear feet I need in the high and low side heat transfer units.
Volume output per minute at a specific working presure would equal volume passing thru the evaporator, with this i think one could calculate how many btu's per minute will need to be given to the system to fully evaporate the freon, by looking at how many btu' s per volume of freon transitionoing from liquid to a gas, (crossing the evaporation curve). with this I could then oveerkill the whole function by say 40 percent, to overcome all the heat loss issues and then It gives some room for balancing with water flow accross the low side. How balanced does the system need to be before problems will come back to haunt a guy like a bad ex-girlfriend? Should I try to make the thing a FOTCC or a VOVCC, how about a TXV system with the on off being the clutch? would half inch line for the high side and three quarter for the low side be adequet? If the High side heat exchanging grid is located about three feet lower than the rest of the system will this lead to oil pooling? I have heard that the A6 is about a 2.5 "ton" compressor then I have also heard that it ia only about a one "ton" compressor ? Where - Where Where oh Where does the truth lie? I am planning on purchasing a manifold and vacuum pump along with the other tools necessary to fill and work on the system as I will have absolutaly no support where the boat resides.
OH yeah I am looking into inch or inch and a half closed cell expanded polystyrene ridgid Insulation board that will offer an "R" value of about 5 per inch. The hull is constructed of Aluminum and has to be insullated. Plan on insulating the low side -- well scrap that thought not much low side before evaporator anyway.
I have scoured the web glad to have found someone (group) that knows more than part numbers and sales by application only. That world is so generic -- makes me want to start slapping people for their ignorance to the world they live in. Anything is possible.. you should see some of the other creations in the engine room of the boat, things you cant buy, things that dont exist anywhere else home made items.
Any way I cant wait to hear back and I dont really know how to use the chat room or much of my computer, I am learning, Its all new to me as of about a month ago.

Later Luke

k5guy on Mon February 16, 2004 2:33 AM User is offline

Having been a small, recreational boater, I know that outside of outer space, the marine environment is the harshest place on the planet. You are talking about compressors and evaps, but all that metal is fodder for the rust gods. You need a really good design, and support if at all possible. I understand the feasibility of what you suggest. Yes, I think it can be done. I also know that in 45 degree F water, you can just bolt your condenser to the hull and use convection to remove the heat. What concerns me is: the amount of metal exposed to saltwater, the possibility of electrolysis (electrical) setting up a current and destroying components, correctly sizing the system, and installing correct controls (thermostat) for your application.

I'm sure NickD can add to this list.

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NickD on Mon February 16, 2004 7:25 AM User is offline

The closest application I can think of is our diary cooling industry such as used for cooling milk in barns, diaries, and in tanker trucks where a stainless steel tube is immersed in the milk as opposed to a finned evaporator. Finned condensers are used, but you have a different situation since you have an ocean filled with 45*F water. The compressors do exist that are electrically driven in the barns and diaries, and separately engine driven in the tankers. We have a number of stainless steel fabricators in the area.

All I can do is suggest you look into this area, and perhaps Detroit_AC can give you some idea as to the specifications of the A-6 compressor or recommend different types. I feel that any automotive grade compressor won't do the job as opposed to the commercial compressors that last for years in the milk cooling industry, but this really isn't my area. I help a friend some 25 years ago with the electrical control of these compressors, but really never dug into them. I would be tempted to look more toward the compressors used in tanker trucks, they can take a bit of bouncing around. You could do a goggle.com search on this subject.

Unfortunately, a main contributor to this board, Mitch recently passed away, he spent his life dealing with ships and had an incredible amount of knowledge in the AC field for marine applications.

LJG on Mon February 16, 2004 11:39 AM User is offline

you say to research detriot ac?, I have been searching "harrison". The Harrison A6 is about the most rugged compressor that can still be belt driven isnt it? As for the corrosion factor, oh yeah stainless is a must, 300 series preferably 304, some oxidation and repaceing or constant maintenance to keep paint on things is a normal thing I do. Having cast steel engine blocks nearly in the bilge making horse power, salt water loves those, but untill someone builts a stainless or titanium engine for unber a bizilion dollars I'll stick with the good old Fe, (iron). sorry to hear about the fallen member. any other sources for compressor sizing or data sheets?
Luke

NickD on Mon February 16, 2004 12:23 PM User is offline

Detroit_AC is a contributing member of this board and that is the handle he uses, a real AC engineer, maybe he will catch this thread or you can post a new thread directing your question to him in the Subject line. "Detroit_AC, need Tech data on an A6 compressor" for example.

Transportation refrigeration is certaining not a new subject, perhaps looking into other fields will help you, just doing a very bried google search on the subject I found this site:



http://www.thermoking.com/thermoking/products/sb_classic_details.asp

You want specifications? Look at this site. Wonder what they want for this unit? Hopefully less than a zillion dollars.

LJG on Mon February 16, 2004 12:54 PM User is offline

Thanks NickD,
will post a new thread toward Detroit_AC. I checked out the thermal king website, did you see the dimensions? - HUUUUUGE Im looking to build a "fillet knife" not a "meat cleaver". Im thinking to try with one A6 pump on one engine to service two fish hatches. then next year if it is successful building two more systems to be installed on the two other engines. Each fish bin holds about a thousand pounds, if I can successfully chill six thousand pounds to grade in four to six hours this will be adequate.
I didn't brief, above deck is a work area that needs to stay open and free from obstruction. Below deck the aft nine feet of the boat is stuffed with machinery already, engines, exhaust, fuel filters and systems, hydraulic pumps, hydraulic tanks, coolant day tanks(overflow bottles), steering systems, wet exhaust mufflers, transmissions, oil coolers, oil filters, three 10 inch kodiak jets, electrical switches and panel, lighting, water- sand separators, three big blocks, hydraulic driven 3-inch pacer water pump, batteries. Its been called the neba-coneza before, the hovercraft from the matrix. All new machinery must integrate and find a happy home amongst the twisted braid.
Luke

NickD on Wed February 18, 2004 6:08 AM User is offline

I guess I didn't look long nor hard enough for one of these self-contained mobile refrigeration units, but they do come in all sizes. Are you saying you need some room left over for the fish?

Detroit_AC rarely visits the off topic section of this site, maybe you should post in the main AC section of this site, you can also do a search for compressors and AC components at:

http://www.thomasregister.com/

Contact the manufacturer and request and engineering catalog.

MrBillPro on Wed February 18, 2004 9:56 AM User is offlineView users profile

I am sure water offers some sort of chill factor like wind does, how cold is the water your in maybe build your some sort of stainless box and drag it along side of the boat lets see if your in 45 degree water and your going 25 knots hm! would that be a water factor of about 28 degrees?

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Don't take life seriously... Its not permanent.

LJG on Wed February 18, 2004 12:23 PM User is offline

In robot voice " can - not - search - any- more - ,system - frustration - reaching -maximum"
maybee Im wrong, but it looks like Delfi or whatever, took over or bought out Harrison they are all electronics now, I don't know. There will be no dragging of condensors through the water especially at 35 knots which is cruising speed. It will be located on the transom under the water line with a spray device to keep it wet when running as that whole area has no standing water after about 15 knots. oh yeah, wet is always better than dry.
I wish it were as easy as it sounds "call up harrison" I may be being retarded, but for the life of me I cant get a number to call and ask for specs, I have heard everything from .5 ton to 2.5 ton rating for the A6.
Ill try DETRIOT_AC with the genral questions post?

I know nothing you know all
Luke Gardner

MrBillPro on Wed February 18, 2004 1:04 PM User is offlineView users profile

There will be no dragging of condenser through the water especially at 35 knots which is cruising speed


No did not mean drag a condenser i meant drag a stainless refer box the fish are in to freeze them. I can see by you reading my post wrong, you are frustrated so i will leave you alone just thought i would try and cheer you up a bit so you did not shoot yourself while searching.

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Don't take life seriously... Its not permanent.

NickD on Wed February 18, 2004 1:54 PM User is offline

Check these out Luke.for some ideas.

http://www.richbeersmarine.com/comlenginedriven.htm

and a bunch of others at:





http://www.google.com/search?sourceid=navclient&q=engine+driven+refrigeration+compressor

Edited: Wed February 18, 2004 at 9:39 PM by NickD

LJG on Wed February 18, 2004 3:28 PM User is offline

You sir, are correct sir, my sense of wit has been greatly dimminished by screen glare, thanks guys, I will check out the links.

LJG on Thu February 19, 2004 1:11 PM User is offline

Yeah the Beers boys are doing things like I have imagined, I sent them some info, and will find out soon on what they can recomend and offer for purchace. looking today on spec sheets for thermal transmission through various metals, boy stainless really sucks. anyone ever dealt with copernickel, or titanium? Titanium is about 25$ a foot but if a guy didn't need much of it and it transfers heat well, it might be worth the investment?
I Know nothing you Know all
Luke Gardner

NickD on Thu February 19, 2004 8:59 PM User is offline

Making some progress Luke. Titanium certainly sounds bulletproof, just have to watch out for galvanic projection if hooking it up to copper.

I wonder if the thermoconductivity would really make that much of a difference, you have basically two junctions to deal with, that between the refrigerant and the tubing and between the tubing and the outside that I believe in your case will be salt water. Each junction has a degree of thermal resistance in so many degrees heat rise per watt of energy transfer, and it's these junctions where most of the loss occurs even more so than the thermoconductivity of the materials used. In a zero resistant system all fluid and medium temperatures woud be identical for a perfect heat transfer, course that would kill the superheat idea in say an evaporator if such was the case.

Auminum can have 5-10 times the thermal conductivity of stainless steel, but both a magnitudes above say the thermal conductivity of air or any gas for that matter. So I would select the tubing material that is most likely to survive in your salt water enviroment. So what are the other guys using?

My salmon fishing is restricted to Lake Michigan where I am luck to catch maybe one or two, and they are eaten before they have a chance to warm up, so I haven't really faced your problem.

LJG on Fri February 20, 2004 3:20 AM User is offline

Holy schniikies, after reading that pondered, on a molecular level, is it very outer edge molecules, having affinity for thier own type (lack of attention toward others) which creates this thermal barrier between the two substances that is higher than in the substance itself? A surface tenision of thermal transfer? deep thoughts - head hurts
I have never examined it at a level that breaks heat transfer down to a heat+heat through+heat out of = heat transfered. for example, when I Installed two motors in the boat at first I welded on keel coolers to cool the coolant, no research,just shot from the hip and made them way bigger than I felt adequet. A few years later when I added a third engine I had to crop a big section of the bottom plate and transom out for the retrofit. The bottom was then refit with a piece of 3/8" 5052 aluminum plate that was trangular, 11 feet long and four feet wide at the aft end. this provided a flat spot to mount the third jet unit in the center of the boat. While the Bottom plate triangle was still new and on the work bench I welded a "keel cooler circut" to it. This was 2 1/2" pipe cut (ripped) in half, and stubbed up custom 2" nipples to conect the coolant lines, but I knew that the contact area wasnt going to be adequet to pass as many btu's as the engine would produce, so I cut 4" pipe in half and welded this over the 2 1/2" and I now rob jet pressure water and circulate it over the 2 1/2" inside the 4" . with this added surface area I could on paper mathmatically barely get rid of all of the potential engine heat. I used these specs with no regard to anything other than how thick the metal was, and how many btu's per unit of time perunit of area. Like say 3/8 aluminum will transfer "X" number of Btu's per hour per square foot. Long story short the unit works, the engine never overheats , except when the boat is out of the water, then the temp climbs very fast and soon over heats. with the engine cooler in the water I am dealing with an unlimited heat sink 45 degree water. I would think that for my condensor I could size it in a similar fashion. the unknown here is the compressor output- If I knew how many cfm output the compressor had at a working pressure say a high head pressure to be safe then I would Know how much matter (freon) is going to at least need to be changed from a gas into a liquid, crossing a condensation curve is a very calculable math problem, times units of mass per unit of time by btu's per unit of mass . Or in other words "X" much freon per minute being pumped should be changed from gas to liquid this will take a certain amount of btu's per unit of freon being changed.
at any rate one could figure that this would yeild btu's per unit of time that will need to be removed to successfully convert all the freon to a liquid. with that I could calculate how many square inches of a certain thickness metal will be required to transfer that many btu's per whatever the unit of time.
My big stumbling stone is the compressor, dont know what an A6 will do? This is my start point for all the math to follow. beings as a properly running system would have a steady low side temperature and pressure this would lead me to believe that the evaporator could mirrror the condensor in heat transfer capacities, this would ensure full evaporation , thus completeing the refrigertaions zero sum circut.

Am I out in left field?

I know nothing you know all
Luke Gardner

NickD on Fri February 20, 2004 7:42 AM User is offline

This paper deals more with head pressure spikes during acceleration, but also has some good general information with it.

http://www.delphi.com/pdf/techpapers/2000-01-0973.pdf

At the very end of the paper are the e-mail addresses of the engineers that wrote it, and perhaps maybe they can answer some of your more basic questions.

I know in the diary refrigeration industry, it's common to see motor driven compressors just like an air compressor set up, but I haven't been able to find these on the web yet.

This site lists some of the Delphi components, note the HT-6 compressor has a 164 cm^3 displacement, so we are getting close to what you are looking for.

http://www.delphi.com/products/commercial/thermal/

The SP compressors even have more data than the HT-6 compressors, since these are both commercial grade, I wonder if they would last longer then what you find under the hood of a Caddy. On the pfd. sheets, you will find contact information for more information. Hope this helps.

Bigchris on Fri February 20, 2004 9:14 AM User is offline

To quote an old friend, "Most A6s are 12.6 cu.in except for corvette and corvair which used 10.8 models."
A6 Displacement

LJG on Sat February 21, 2004 3:00 AM User is offline

long day pouring concrete today, big party tomorrow , will get a look at those link later thanks guys, over, out
Luke Gardner,

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