A/C condenser location

SS MAYFLOAT · Feb 23, 2005

Yep, I'm out of the cellar! Its confirmed now, I have a dock with shore power. Its been 3 years on the list and now I'm there. Here is the scoop. Boat is a cabin cruiser (make/year unimportant) I'm installing the compressor in the bilge, evaporator/air handler in the head. and I want to put the condenser coil under the swim deck. I will only be using the A/C while on shore power. I was thinking that with the coil submerged that I would get enough thermal transfer into the water. Of course while I'm underway the coil would then be out of the flow of water. This way I won't need to mount the coil with fans running making noise. With the air handler in the head, all the condesate water can go into the holding tank. So what do you think? BTW I'm certified in the field. Thanks....

Reel Poor · Feb 23, 2005

Re: A/C condenser location

Is this a marine system? !!!!!!!BTW Im "CERTIFIABLE" in the field!!!!!!!

Dunaruna · Feb 23, 2005

Re: A/C condenser location

I can see that submerging the condensor might seem like a good idea but I'd be concerned with how the alloy would react to - 1. Being submerged. (it probably isn't marine grade alloy) 2. Galvanic corrosion, the soft alloy will become a sacraficial anode. I'm also certifiable.

Aldo

ob · Feb 23, 2005

Re: A/C condenser location

Is a window unit out of the question?What tonage are you contemplating?I agree with Dunaruna on the problems with condenser coils submerged. I am also certified btw.

Concievably by submerging the entire condenser coil you could exceed the necessary 30 degrees of sub-cooling necessary for condensing the discharged refrigerant vapor and cause liquid migration to compressor.Not good.The fins would also not be needed for conduction on a submerged type condenser.Sort of like a tube and shell condenser.

SS MAYFLOAT · Feb 23, 2005

Re: A/C condenser location

Thanks ob, gee I didn't know our Aussie friends were governed by the EPA? Like I said, these are ideas that I'm wanting. Keep in mind this boat only sees water about 3 or 4 months out of the year. Fresh water not salt. I would like to get one of those units that fit in the bow hatch, but I need that access frequently to tend to the anchor. Plus also the cost of the unit to the amount of time it is used is not feesible. ob, You saying that the condeser coil will flood with liquid. I always thought that the condeneser coil was to convert hot gas to liquid.

Now if the evap coil was lower than the compressor and condenser coil, I know I would have problems with oil/liquid entrapment. This system will be a TXV system not a cap tube. I figure that I have about 180 square feet. Not a big area, but with no insulation I'm figuring about a small 6500 btu unit should do fine. The windows are tented with screens that also cut down on sunlight about 70%. I thought about a window unit, but I don't want to do any hacking. Plus to me it looks tacky. Another option would be to install a water cooled condenser. I have several of those on the shelf. I was just trying to elimate moving parts. With a water cooled coil, I would then need to install a water pump. Reelpoor, to respond to a post to insult me is totally wrong. I've been around here for quiet awhile and I feel that I'm respected by others. I do hold a universal EPA certificate. If I had all the answers, I wouldn't be posting. Others on this board have excellent ideas and pass them on to those that are asking for help. I'm just wanting ideas to come up with a system. If I worked on boat A/C's I wouldn't be asking for help now would I?

Dunaruna · Feb 24, 2005

Re: A/C condenser location

SS, I don't know about reelpoors comments but my comment about being certifiable was just a bit of fun - I'm certifiable as in I should be in a nuthouse

Sorry for the mix up. BTW, EPA (in Australia) does control the aircon industry. Aldo

ob · Feb 24, 2005

Re: A/C condenser location

Actually ,I'm not sure that a submerged fin type condenser coil would cause a liquid backup problem.Just a conscience concern I would bare in mind.The change of state from hot refrigerant gas to liquid takes place in the final few passes of the coils in an air cooled condenser by design.If you insure that the entire charge would be able to be pumped down or stored in the condenser volume ,I think my concerns would diminish.If you choose to use a watercooled condenser(tube and shell)and the refigerant is passed thru the shell side,you may be able to just run it submerged without a media pump,and the end bells removed.Sorta using it as a static condenser with an endless supply of cool water. I guess beauty is in the eye of the beholder,but they make some pretty steamline camouflagable window or deck units that would handle that square footage on 115 volts.In any case ,your project sounds interesting.

Reel Poor · Feb 24, 2005

Re: A/C condenser location

SS the exclamation I posted was not ment to insult you. If youll reread it, its actually a poke at myself as being certifiable. Sorry for the mix-up.

waterone1@aol.com · Feb 24, 2005

Re: A/C condenser location

While I may be certified....as a nut, I am not certified in HVAC, however, just wanted to remind you that few marine or otherwise compressors are explosion proof. You said that the boat and set-up were unimportant....if it is not gasoline powered...that is correct, otherwise, that is an issue. While I cannot comment on all of the details of a hvac installation, I can say that unless you are running diesel fuel, anything of your installation that is in the same compartment as the engines and fuel tanks must be ignition protected or explosion proof.

SS MAYFLOAT · Feb 24, 2005

Re: A/C condenser location

Reelpoor, no problem. I get a little aggrivated when I'm coming up with a plan. Hope I wasn't too hard on ya. Thanks waterone1, I'm very aware of the use of explosion proof requirements for the bilge. As for the compressor, if it would explode, the refrigerant gas would deplinish the oxygen that is needed for fire. The wiring connections to the compressor would be in its sealed juction box that is on the compressor. So if there would be a problem, it would be contained in the j-box. ob, I got on ebay an checked out some units. Glad I did, it gave me some answers and ideas. I talked to my wholesalers engineer. He said if I could find some 5/16" stainless tubing and make a coil to be submerged would work excellent. All the electronic controls will be mounted in the cabin to meet USCG requirements. It would be great if I could find a unit that has a bad compressor or coil. If I don't use the submerged coil idea, I have a water cooled condesner that I can use. I have a volvo 280 outdrive, I could "T" into the raw water line (before the pump) to install my circulating pump. Of course I would intall a backcheck valve going into the circ pump. Then the raw water pump won't cavitate due to pulling water back through the circ pump. Thanks for the help.

ob · Feb 25, 2005

Re: A/C condenser location

Sounds like a plan SS.Keep us updated on your project.

tommays · Feb 25, 2005

Re: A/C condenser location

SS As for the compressor, if it would explode, the refrigerant gas would deplinish the oxygen that is needed for fire. the problem is not the compressor explodeing its with the gas fumes the compressor motor will explode. if the motor is not rated as well as the whole unit theres nothing you can DIY to make it rated tommays

SS MAYFLOAT · Feb 25, 2005

Re: A/C condenser location

tommays, thanks for your concern. The compesors used in marine air is the same as you would find in a window unit. There are several types of compresors. Belt driven, semi hermetic and hermetic. I would be using the hermetic. I have been in this profession for more than 20 years. To this date I have never ever seen a hermetic compressor explode or blow up. I have seen one that threw a rod out of the case. All that happened was the refrigerant and oil blew out of the hole that was poked in the side. Keep in mind that these compresors have ratings of 400 to 500 pound test pressure. During normal usage on a hot day, the high side maybe from 250 to 300 psi. High pressure cut out would be 325 lbs head pressure. If a compresor would short out, all it would do is blow the breaker. There is no way it can start a fire. To satisfy those who is not sure what the USCG requires on air conditioning systems, I will try to get some info and post reference to it. Geesh. If you don't know much about refrigeration, then don't post.

tommays · Feb 25, 2005

Re: A/C condenser location

SS i no a thing or two about air conditioning but would never assume to have your knowledge about AC BUT i do no a lot about ratings for hazardous locations as I work in them on a daily basis and you cant use a standard AC unit in a location that requires a rating like a boat bilge Even a simple 15000 btu window mount cost about 1600 dollars retail about 3 times the price of a standard one I guess they would not make them if a standard unit would be safe enough I can only say that just like your starter ,alternator ,and other special marine electric parts this falls in to the same area and requires a rating to be used in the bilge Your in the AC trade look up the price of a compressor with a explosion proof rating

SS MAYFLOAT · Feb 25, 2005

Re: A/C condenser location

Tom, I understand what you are saying about window units vs marine units. You are talking about the whole complete unit. I am only talking about the compressor only. No blower, no contactors, and nothing that would be an ignition source. A hermetic compressor has all the components encased in a steel jacket. It cannot leak at all. If it did, the refrigerant would leak out and the system would not work. My wholesaler looked at me funny when I asked him if there was a difference between marine and non-marine. There is no listings for marine apps. This includes Techumseh and Copeland. There is not any listings for explosion proof compressors either. I don't know how to explain it any better. The only thing I would put into my bilge is the compressor. It would actually be safer than any other item in the bilge. The starter is arc proof but not water tight, the alternator is arc proof but not water tight, the distributer is arc proof but not water tight, and a refrigerant compressor is arc proof and is definetly water tight! The air handler that has the blower in it would be in the cabin. The cabin has a sealed bulkhead to the bilge. The cabin can use normal appliances UL approved, which all componets of the air handler has. Sorry for getting long winded, plus I was asking about the conderser location under the swim deck. Which I have found out through an engineer the length of tubing that I need. Thanks.

tommays · Feb 25, 2005

Re: A/C condenser location

ss maybe i am worng but they make them and they cost a lot more just the fact that they have had the tests to get the rating cost a lot more and the high and low pressure switches are not the same a standard unit units are not ignition protected and must not be installed in an area where flammable vapors may be present. http://www.google.com/search?hl=en&q=explosion+proof+air+conditioners&spell=1 http://www.google.com/search?hl=en&q=marine+air+conditioners&spell=1 Air Cooled & Explosion Proof Marine A/C Systems i am only trying to make you aware that there are differences that may not be apparent because its not a normal AC job to do an area that has a exp rating tommays

SS MAYFLOAT · Feb 25, 2005

Re: A/C condenser location

Okay, Okay you got me on the EXP rating. However according to the USCG the bilge in my boat does not require EXP rating. If it was, I wouldn't be able to use my engine, bilge pump, blower, water pump, and any other accessory that is down there. All the USCG requires is for a spark, ignition protected. This isn't for a big yacht, heck if it was, I wouldn't even be here. If it is that big of a deal I can put the compressor behind the fridge in the cabin. You learn something every day. Guess I did today. Thanks Tom.

tommays · Feb 25, 2005

Re: A/C condenser location

ss good luck with the install the spark/protected rating is the marine verison of the EXP rating on land they are different but both have the same goal to be safe which is a big reason are fun costs so much money tommays

A/C condenser location

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