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Narrowboat Aircon Using Canal/River Water?


jono2.0

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Whilst sitting in my narrowboat yesterday in the hot heat I thought about air conditioning.  There are basically two separate areas of air con.  A compressor that cools water and air passed through the cold water, in turn creating cooler air.

We all know a fridge compressor works pretty full on when the inside of the boat is especially hot. Air con would also be very power hungry.  But the boat is surrounded by water that is significantly cooler than the air, just putting your hand in it shows that.  Could I use water from the canal/river to circulate through some sort of radiator mechanism just like an air con unit would use and then push air through it?

I could have a small low power pump circulating the water and a fan pushing the air.  I realise it wouldn't be as cool as a dedicated air con unit but surely it could be achieved?  What are your thoughts?

   

Edited by jono2.0
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In this country it would only be useful for two or three days in a typical summer. I reckon a small bilge pump sucking water from the cut and a spray nozzle to coat the roof would work well and be very cheap. Many boaters have a spare bilge pump anyway. Lots of heat removed as the water evaporates. It would encourage algae growth, but I could cope with that. Must admit weekends like this I start planning to repaint the boat white!

Jen

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23 minutes ago, jono2.0 said:

A compressor that cools water and air passed through the cold water, in turn creating cooler air.

There is 'nothing new' in this world - your suggestion has been the 'standard' method of air-conditioning for boats for 40+years.

Dometic are now the market leaders.

Quote :

Air-Conditioning systems reject heat from the space to be cooled into the surrounding seawater via the refrigerant flow in the sea-water cooled condenser

 

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I think your quote is talking about a 'refrigerant' being cooled by the river or canal water. I've worked on boat air con like this, with the condenser having sea water forced over it. The OP is asking about using the colder canal water to cool the air directly.

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4 minutes ago, pearley said:

I think your quote is talking about a 'refrigerant' being cooled by the river or canal water. I've worked on boat air con like this, with the condenser having sea water forced over it. The OP is asking about using the colder canal water to cool the air directly.

Could well be - all I know is you connect 'cold water' to a 'box' and cold air comes out of the vents - its all magic in between.

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Just a thought - As the entire base plate of your boat will be close to canal temperature, you have a good supply of cold air in the bilges which you could pull into the boat with a fan, however in a shallow canal with lots of sun, I can see the water temperature rising to 15c or more (just a guess - it could be more around a hot boat) but the bilge air will be cooler than the cabin air, but I am not sure it will be cool enough to make a significant difference to the entire boat, but you may be able to cool down a comfy corner in your cabin.

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The concept is fine - execution is quite another matter.

I installed air to air conditioning into a computer room in the 70's. There were three units each rated at 3Kw and I think the effective cooling was about 1Kw each.

To make the idea work you need a "heat pump" to pump the heat from within the -whatever- to the outside. You'd need a lot of 'leccy to power that.

Pouring water over the roof doesn't work either - been there - it just made the cabin more humid. Now if not cruising, we use a number of large computer fans and sit near them... 

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Marine AC units work exactly the same as air cooled units but via a water cooled condenser, very much like the difference between an air cooled and water cooled engine. The are however very power hungry. I have never installed one on a narrowboat but have installed the Webasto ones on sea going craft that have generators and or shore power in the marina.

 

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I have a computer fan over a hole in the floor behind the fridge.  It is connected to the fridge so only runs when the fridge is running.  The air around the fridge is noticeably cooler than when the fan is not running.

It might be worth trying.  Although the canal water can feel quite warm, it is much cooler 60 cm down so the base plate stays cool.

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2 hours ago, NMEA said:

Marine AC units work exactly the same as air cooled units but via a water cooled condenser, very much like the difference between an air cooled and water cooled engine. The are however very power hungry. I have never installed one on a narrowboat but have installed the Webasto ones on sea going craft that have generators and or shore power in the marina.

 

always surprises me when a substantial American organisation calling itself the National Marine Electronics Association manages to post in a forum like this, using the first person 'I', and claims to be based in London and Fambridge, and has 2 boats to its name.

how does that work exactly?

 

.............  or to put it another way: are you (whoever you are) actually authorised by the NMEA to post on their behalf?  I would never dream of posting on behalf of, or using the name of, the Institution of Civil Engineers.

Edited by Murflynn
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1 hour ago, Murflynn said:

always surprises me when a substantial American organisation calling itself the National Marine Electronics Association manages to post in a forum like this, using the first person 'I', and claims to be based in London and Fambridge, and has 2 boats to its name.

how does that work exactly?

 

.............  or to put it another way: are you (whoever you are) actually authorised by the NMEA to post on their behalf?  I would never dream of posting on behalf of, or using the name of, the Institution of Civil Engineers.

....that seems a bit OTT.

Just 'cos you call yourself NMEA, doesnt mean you are NMEA....I mean, I'm no Muppet .....oh..maybe I am...let's not go there then!

It is useful to get some informed opinion from someone who has installed kit for a living (and says so in the post). Air con units in boats (lots in use in the Med) use big amounts of power.

For the OP, I think the idea of using the colder air in the bilge has legs.

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10 minutes ago, Dr Bob said:

....that seems a bit OTT.

Just 'cos you call yourself NMEA, doesnt mean you are NMEA....I mean, I'm no Muppet .....oh..maybe I am...let's not go there then!

It is useful to get some informed opinion from someone who has installed kit for a living (and says so in the post). Air con units in boats (lots in use in the Med) use big amounts of power.

For the OP, I think the idea of using the colder air in the bilge has legs.

Second that. Having struggled to find an appropriate name for some time.... 'NMEA' to me, is concise and explains his interest and a guide to his knowledge. There's no equivalent UK body - the US has a huge market for boats; ours is tiny by comparison.

 

 

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Air conditioners are heat pumps.  They should be able to transfer 4kW of heat per kW of input energy.  The term used is coefficient of performance. CoP is about 4

Solar panels on the roof will help to keep the roof cool.  Solar thermal panels could help and provide hot water.  You could always dump the hot water when you cylinder was hot.  I think the cooling water inlet would need to be in or close to the base plate.

 

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1 hour ago, Dr Bob said:

....that seems a bit OTT.

Just 'cos you call yourself NMEA, doesnt mean you are NMEA....I mean, I'm no Muppet .....oh..maybe I am...let's not go there then!

It is useful to get some informed opinion from someone who has installed kit for a living (and says so in the post). Air con units in boats (lots in use in the Med) use big amounts of power.

 

if the gent involved called himself "NMEA member" or such-like, then that would be fine.

but his username and avatar imply that he IS the NMEA (i.e. everything he says is the official and considered view of the NMEA) which he definitely isn't.

if you think about the possible ramifications of this apparent deception you may decide to revise your opinion.

 

as I said earlier, if my username was I.C.E. and I used the Institution's heraldic crest as my avatar, then if I expressed an opinion on a civil engineering matter (of which I have 50 years' experience) then it could reasonably be mistaken for the Institution's considered opinion.   I would never be so arrogant as to imply any such thing.  I would be very surprised if the Association involved has authorised his use of their name and avatar in this way, and consequently it would appear (to me at least) that he is acting unprofessionally.  

This is not a new issue, I raised it several months ago.

Edited by Murflynn
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9 minutes ago, Murflynn said:

if the gent involved called himself "NMEA member" or such-like, then that would be fine.

but his username and avatar imply that he IS the NMEA (i.e. everything he says is the official and considered view of the NMEA) which he definitely isn't.

if you think about the possible ramifications of this apparent deception you may decide to revise your opinion.

 

as I said earlier, if my username was I.C.E. and I used the Institution's heraldic crest as my avatar, then if I expressed an opinion on a civil engineering matter (of which I have 50 years' experience) then it could reasonably be mistaken for the Institution's considered opinion.   I would never be so arrogant as to imply any such thing.  I would be very surprised if the Association involved has authorised his use of their name and avatar in this way, and consequently it would appear (to me at least) that he is acting unprofessionally.  

This is not a new issue, I raised it several months ago.

Do see your point,I possess a Boatmaster's Licence BUT would not head any Letters with M.C.A

CT

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27 minutes ago, Murflynn said:

if the gent involved called himself "NMEA member" or such-like, then that would be fine.

but his username and avatar imply that he IS the NMEA (i.e. everything he says is the official and considered view of the NMEA) which he definitely isn't.

if you think about the possible ramifications of this apparent deception you may decide to revise your opinion.

 

as I said earlier, if my username was I.C.E. and I used the Institution's heraldic crest as my avatar, then if I expressed an opinion on a civil engineering matter (of which I have 50 years' experience) then it could reasonably be mistaken for the Institution's considered opinion.   I would never be so arrogant as to imply any such thing.  I would be very surprised if the Association involved has authorised his use of their name and avatar in this way, and consequently it would appear (to me at least) that he is acting unprofessionally.  

This is not a new issue, I raised it several months ago.

Yes you did raise it and its a very quick and easy way to p1$$ off (as it did last time) one of our valued technical contributors.

Tell me Muffin what have you contributed technically to this forum that could be of use to fellow members?

ETA we use a portable aircon unit just inside the stern doors, cools the sleeping area and as we are outside in the shade we don't really care that the front is at 33deg

Edited by Loddon
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In the 1980's some telephone exchanges were cooled by circulating chilled water through ceiling mounted radiators and raining the cold air between the equipment racks, so you idea is viable. 

However most telephone exchanges, and and an increasing number of data centres now use "free cooling",  which is basically big fans forcing air at ambient tempersture from outside the building past the equipment at a high velocity.

Both systems cool well, but it is much cheaper to buy a big fan and force lost of air through your boat than installing heat exchangers, pumps, pipes and radiators. It also has the advantage that air leaks are less messy  than water leaks. :P

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To this I can only add a feeling of envy. I have had to stop work on my sailaway as I can only liken it to poor Alec Guinness incarcerated in the corrugated "shed" in Bridge on the River Kwai. No matter how much I drank I just dripped all over the work in progress. Nothing seemed to fit or would stay in place. A cold one is now to hand and my mood improving.

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