Various uses for heating ducting

[waterboy]

With all that tubing taking up so much space set my mind ticking. Why only use it for the Eber? How about, when connected to shore power, having a AC powered heating element somewhere in the tubing? Using the fan in the Eber, hot air is efficiently distributed around the boat, far more efficiently than any stand alone fan heater can do and probably quieter.
Secondly, again when on AC, how about linking the tubes to a dehumidifier? I'm not sure whether the tubes should be used for dry air exhaust or moist air intake but we could be certain of better distribution.
Finally, my current 5 port Eber has no cool air setting for the summer. Could I fit Air Con in somewhere?

 

[Talbot]

your eber should have a fan only setting - read the manual again.

 

[sailorman]

& buy a fan heater /forums/images/graemlins/wink.gif

 

[ytd0]

you generally need to double heater duct diameter for cooling. Built in air con is expensive and needs a big genset to run it. Cheapest option is a caravan roof mounted air con fitted to the companionway hatch - for marina stays only.

 

[DaveS]

Leaving aside the aircon idea, I think that in principle fitting an electric heating element for running off shore power is not at all daft. If you're contemplating the DIY route it will require a little thinking about to ensure safety, however. The situation to consider is your electric heater drawing power but with no airflow: fan failure, physical blockage, whatever. Solving this is not trivial: e.g. a conventional thermostat is of little use. Ideas to consider:

1. a thermostat fixed at the top of the duct directly above the heater element and set to respond to a temperature which would only be reached under these conditions: not intrinsically fail safe, however, so maybe two wired in series to improve the odds?

2. self-limiting elements: these do exist commercially and are fail safe; the 55 degC hot water services tracing tape is probably the best known, and something could probably be arranged using this, but it would require a long length (expensive and difficult to find room for: too much folding up would over fill the duct).

3. semi-conducting silicon elements: similar to 2. but with a higher temperature so smaller and used commercially on a number of miniature fan heaters usually sold mail order with lots of hype and silly prices. If you could locate a source of these elements that might be best of all.

It would of course be much simpler if a suitable duct heater module was available off the shelf. Such things certainly exist in bigger sizes, but I don't know of anything suitable for a boat. Does anyone else know better?