New water maker thoughts?

[geem]

Another thought for the OP: this forum has several members who have constructed - and full marks to them for effort, ingenuity and parsimony - a water maker which uses two pumps: a low-pressure one followed by an old-fashioned, noisy and inefficient high-pressure pump, few, if any, of which were designed for use in salt water. These often are sourced from pressure washers.

On the other hand most modern water-makers (Spectra, EcoHydro etc) use a purely mechanical device to make the high pressures from the low pressure feed pump alone. This is energetically possible for water makers as they all need a fairly high bypass ratio (although tbh I don't understand the full physics of the limits, high and low, of this factor). It's called a Clark Pump, and makes for quieter, more energetically efficient and more reliable operation.

The trade-off is home made, and so money saving (and - a real plus point this - you fully understand it) versus a bought but higher tech product. I can't say which will appeal to the OP more. For me, although I have made several things for the boat myself so was tempted to go for the home-brew version of the water-maker, energetic efficiency was the deciding factor. Hence the Spectra.

You only need an energy efficient watermaker if you are going to run it from your batteries. You have to consider that batteries have quite a lot of demand from fridges/freezers and other devices. Using solar you can recharge you batteries during the day but this becomes less efficient if you are running a 12v watermaker for several hours a day because the output is poor. The OP has already stated that he has a new generator so he doesnt need to stress his batteries. A high output generator run watermaker will allow his batteries to fully charge each day and he will have plenty of water. A simple low efficiency (no Clarke pump) watermaker is a simple device with less to go wrong. You need a generator to be reliable but with a new one you would hope that wouldnt be an issue. By the way, Echotec dont use Clarke pumps. My home built watermaker is almost identical to the Echotec units. Very few people use pressure washer HP pumps. There are stainless pumps and bronze versions designed specifically for use in salt water. My Cat 247 pump is one such unit

 

[Neeves]

You could include in the mix Rainman who produce an almost complete range of desal units.

Rainman Watermakers & Saltwater Desalinators. Portable or Installed.

I've used their portable original unit that ran of the small Honda engine but they now produce other units.

I know of them as they are local - our unit is a Spectra.

Jonathan

 

[Tanqueray]

Wow!

I have to say that when I posted I was half expecting no replies at all - seriously impressed with the responses even down to building your own water maker. Very much appreciated, thank you all.