Winter on the Water. Part 2

In an enclosed space, of a home (domestic property), on in this case, my boat, there are essentially three ways to stop condensation forming on cold surfaces; and these are fairly straight forward.

1.      Raise the temperature of the cold surfaces above dewpoint.

2.      Remove water vapour from the air

3.      Prevent the water vapour getting into the air in the first instance.

The later, being the most obvious, was the area I tackled first.

Water vapour appears in the air for many, many reasons; here’s just a few

·        Drying washing on radiators

·        Drying bathroom towels

·        Cooking

·        Boiling the kettle

·        Ironing

·        Living and breathing

·        Bathing

·        Showering

Many of the above don’t apply to me and outside of the Royal Yacht Britannia and other super yachts, a little above my price range, baths aren’t a standard fitment so this can be disregarded too; obviously ironing is something I avoid with a passion so this is not a major contributor either, which leaves cooking, boiling the kettle and generally, living as the primary contributors.

Many houses have an extractor over the cooker but often, people only turn it on when the kitchen windows have steamed up. I didn’t have a cooker hood, but it became clear that I needed one.

In the confines of the galley, a household cooker hood was too big (and typically running on 240 volts too) so a yacht friendly one needed to be manufactured.

This turned out to be easier than I thought as a stainless-steel roasting dish was turned upside-down, had a 100mm hole cut through and was fitted with a 12-volt fan (the cooling fan from an old computer). The unit was then suspended from the galley deck head and the fan outlet ducted through a deck vent.

It was perfect; well, nearly.

The vapours from cooking and from the whistling kettle were extracted really easily but the electric kettle was difficult. In most domestic properties, the kettle is closer to the sink than it is to the cooker and my situation was similar. This was quickly resolved with a modified TV wall bracket which allowed to kettle to swing under the roasting tin hood when needed and swung away for cooking.

Condensation on the dehumidifying windows in the saloon and forward cabins reduced massively and the cooking smells virtually disappeared too but another significant producer of humidity was harder to deal with.

As a typical human, I lose approximately 700ml of water from my lungs and my skin and a further 200ml through sweating; that’s nearly a litre per day.

My girlfriend (also being human) must lose similar, so when she’s on board, that nearly two litres between us and during ‘quality time’ we probably lose some more.

Clearly a different from of water vapour extractor was needed and this was going to be a dehumidifier – and not just any old dehumidifier either. My dehumidifier needed to be small, as I don’t have a lot of space, and a desiccant (absorption) dehumidifier since refrigerants don’t work so well when the air is cold, and it is the cold which caused the bulk of the problems. It also had to be of a low capacity since my shore supply (power cable) is 16 amps max and 13 amps continuous.

Ecor make two superb desiccant dehumidifiers which fitted the bill perfectly; called DryFan 8 and DryFan 12, they are typically used for crawl spaces and boats, and since I have a boat, these are for me; thus, I now have the Ecor DryFan 8 which not only removed 8 litres per day, it is only 8” square (200 x 200mm) and its diminutive size lends itself perfectly to my application.

With some slight modifications onboard, the DryFan outlet was fed into the intake of the diesel fired blown air heater and the wet air exhaust fed out of the engine-room breather so I now have not just warm air, but warm and dry air circulating around the cabins. If I don’t need the heating but just the dehumidification, the DryFan pushes its air past the diesel blower and into the ductwork so the cabins still receive dry air anyway

At 8” square, the DryFan 8 is limited as its airflow is only 90 m3 per/h but its energy input is only 0.35 kw (1.5 amp) so using it in the way that I do, it works perfectly, and the net result is no condensation.

Thinking conventionally, many small terrace houses and flats aren’t much bigger than my boat so it would work equally well for general moisture extraction in a domestic property too.

Further information about the Ecor DryFan range can be found here: -

https://ecorpro.eu/product/dh800-dryfan-8-litre-desiccant-dehumidifier/

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