If you purchase
a split system off the shelf system, it can be used while in a marina where you purchase
240 VAC power. It won't disturb anyone. If the condenser is on deck
, remember that it is prone to corrosion
as they often have both copper and alloy components. The sheet steel
"boxes" also have a limited life. However, if you run it from a genset, you need to ensure that the gen set will provide the large starter current
needed for the system. A frigie chap may suggest a bypass at start up to reduce the current
Using a water cooled condenser has some big advantages but cost isn't one. Copper nickel alloys are used and these alloy exchangers are expensive.
Also in the tropics, water temperatures can be very high particularly in shallow dirty river water which is a Cooktown feature. So when purchasing
a water cooled condenser, make sure you are aware of this so water flow rates adequate.
I use a home made water cooled condenser. You need a steel
pipe of about 10 cm outside diameter, a lathe and a coil of half inch copper pipe. You put the steel pipe (about 80 cm long) into the lathe and turn it at a very low speed. You feed the copper pipe onto the steel pipe making a close spaced helix from one end to the other. Turn the copper tube and return the spiral. You may build up possibly three layers of copper spiral wound tubing. (Mine use two layers.) Ensure that the two ends are protruding at the same end. Take the copper spiral off the steel mandrel. Some joining may be required, to retain the overall shape. Use plastic.This spiral arrangement is placed inside a 200 mm PVC tube with a glued on end cap at one end and a screw on end at the other. The two copper pipe ends come out the sealed end. You will need to work
out how this will seal. I used all plastic fittings. Some glued in with backing washers and threaded parts
on the outside to allow off the shelf fittings. The copper tube carries the refrigerant gas/liquid and will undergo expansion/contraction during use so the two end seals
need to be "flexible".
At the other end, I used a large screw on cap. This removable cap has the water inlet and outlets (the inlet is connected to a soft hose that transfers water internally to the other end). You will also need to install zinc anodes and this is best done on the flat surface of the screw on end cap. You need to run a wire from the external anode connection to the copper pipes at the other end to complete the protection circuit.
The two end copper pipes will need to be joined into the discharge and return refrigerant lines and I have used flexible car A/C hoses and fittings plus I also have installed close off valves to isolate the copper pipes and others to isolate the remaining refrigerant plumbing
If you mount this vertically with the water/anode end at the top, you can easily replace the zinc anode(s). Make sure the zinc anode does not touch the copper pipes. A drain at the closed end base allows the system to be flushed.
I also allow the system to be completely drained when A/C isn't needed which prolongs the life of the copper pipes. This system has been in place for over 30 years. The only drama occurred when I inadvertently connected the water supply up to mains pressure and it simply blew the end cap off! Embarrassing.
My system uses a dedicated Tecumseh 1000 engine driven compressor so I generally don't run it in marinas
, but it works well at sea.
The heat exchanger
described can be used for freezers or AC systems. I built the exchanger simply because it was more cost effective than the copper nickel alternatives. It is a mess of pipes, fittings and valves, but at least I can manage any repairs
. It is also bulky.