Narrowboat Aircon Using Canal/River Water?

[Drayke]

How about going to a scrap yard (yah I know not PC) and buy a radiator with fan attached, along with a circulating pump and some hose piping, plumb all that in. That should work and it would all run off of 12v.

[Jess--]

not boat aircon but recently fitted home aircon.

we have a 2.5kw unit that we have just fitted which in the recent hot weather just managed to hold the temperature in the office at 22 degrees
the air coming out of the unit varied between 6 and 8 degrees (internal temps were at or below freezing, external unit temps were above 40 degrees).

I think that if you were using canal water (which would probably be somewhere around 18-20 degrees in hot weather) you would get very little cooling from it and almost certainly not enough to combat the heat being collected by the steelwork of a narrowboat.

condensation would be a real concern, our unit has a drain to outside (so no drips inside), out of interest I put a bucket under it to see how much water it was condensing out of the air in the office, from 3PM to 10PM (7 hours) it filled a 5 gallon bucket 1 1/2 times.

I think you would be better off (in terms of efficiency) by using a pump to spray water over the roof of your boat (lawn sprinkler) and getting the cooling effect from evaporation.

Edited June 23, 2017 by Jess--

[system 4-50]

Conjecture: If you spray water over the boat then the air will be saturated and evaporation from the surface will be severely reduced. Ideally pour the water thinly over the surface with a strong breeze (however obtained) for maximum cooling. It's the latent heat of evaporation that you're after, not the simple transfer of heat from the metal to the water? Or am I way off the mark here?

Edited June 24, 2017 by system 4-50

[Chewbacka]

59 minutes ago, system 4-50 said:

Conjecture: If you spray water over the boat then the air will be saturated and evaporation from the surface will be severely reduced. Ideally pour the water thinly over the surface with a strong breeze (however obtained) for maximum cooling. It's the latent heat of evaporation that you're after, not the simple transfer of heat from the metal to the water? Or am I way off the mark here?

I agree with you that it is the latent heat that will cool the boat, however there is usually some breeze, but even on a completely still day I would expect the sun to warm the steel work such that the air in contact will get warm/hot and will naturally rise taking the water vapour with it.  I doubt a fan would help much unless it was massive, and then you would have to run the engine to power it and that would make the boat warmer......  However if using canal water you are going to end up with some interesting drying stains all over your steel work.

[mrsmelly]

On 6/19/2017 at 15:50, Machpoint005 said:

All we need now is a fridge that operates on the energy it extracts from the food it is cooling.

All these things have long been possible. We all know the proven fact ( By those who have bought one ) that Eco fans even when stood on a cold solid fuel stove will produce and distribute evenly enough heat to completely warm a seventy foot narrowboat inside around eight minutes.

[Murflynn]

27 minutes ago, Chewbacka said:

I agree with you that it is the latent heat that will cool the boat, however there is usually some breeze, but even on a completely still day I would expect the sun to warm the steel work such that the air in contact will get warm/hot and will naturally rise taking the water vapour with it.  

agree 100%; you will never affect the humidity of the air surrounding the boat to any significant degree; to prevent evaporation it needs to be in the order of 100% which will never happen on a sunny day.  On a hot day the effect of water spray alone will be enormous.

I recall my kids on the beach when we lived in Oman.  On a typical sunny day with temperatures in the 40's, when they came out of the water we had to wrap them up in beach towels because they were seriously shivering as the water on their bodies evaporated.  The effect is immediate and very significant.

[cuthound]

2 hours ago, system 4-50 said:

Conjecture: If you spray water over the boat then the air will be saturated and evaporation from the surface will be severely reduced. Ideally pour the water thinly over the surface with a strong breeze (however obtained) for maximum cooling. It's the latent heat of evaporation that you're after, not the simple transfer of heat from the metal to the water? Or am I way off the mark here?

In extremely hot weather,  when the air conditioning installed in data centres cold not cope, as an emergency measure we used to spray water from a hose onto the condensor coils. Used to bring the temperature in side the data centre down,  so yes it will work.

[nb Innisfree]

Several years ago during a very hot spell we were moored next to a white painted  steel narrowboat,  The difference in roof surface temp between the two boats was remarkable, our dark green surface was unbearable to touch, literally hot enough to fry an egg on whereas the white boat actually felt cool. 

[Profzarkov]

Hmm, I was pondering this question too - during that heat wave but it wasn't just a one off - last year we had weeks of "a bit too hot to sleep".

A simpler system would be two car radiators (used), some plastic piping and a water pump - stick one in the canal - prob horizontal and t'other in the boat with maybe a fan behind it. Wouldn't cause freezingly cool air but it would cool things down and with no compressor, probably cheap-ish to run?

[Dave_P]

On 6/18/2017 at 10:27, Chewbacka said:

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.

Canal water temp in the summer is usually in the low 20s. Much warmer than you'd think. 

[rusty69]

11 minutes ago, Dave_P said:

Canal water temp in the summer is usually in the low 20s. Much warmer than you'd think. 

Thats much warmer than i thought. 

[cuthound]

13 minutes ago, Dave_P said:

Canal water temp in the summer is usually in the low 20s. Much warmer than you'd think. 

The temperature will depend on the depth. I expect it to be a fair bit colder near the canal bed in the deepest part.

[Dave_P]

15 hours ago, cuthound said:

The temperature will depend on the depth. I expect it to be a fair bit colder near the canal bed in the deepest part.

You'll get a thin layer of warmer water at the surface on a sunny day but the rest is pretty consistent in my experience. 

[blackrose]

On 18/06/2017 at 09:25, Jen-in-Wellies said:

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

I know a bloke who made loads of small holes in a couple of hoses and laid them on his roof to constantly spray his boat with water. The hoses were fed from the mains water supply at his mooring. Wasteful yes, and he soon discovered it made absolutely no difference to the temperature inside the boat.

[Phil Ambrose]

On ‎24‎/‎06‎/‎2017 at 08:16, mrsmelly said:

All these things have long been possible. We all know the proven fact ( By those who have bought one ) that Eco fans even when stood on a cold solid fuel stove will produce and distribute evenly enough heat to completely warm a seventy foot narrowboat inside around eight minutes.

Rather random, introducing ECO fans into the discussion 

Phil

[mrsmelly]

2 minutes ago, Phil Ambrose said:

Rather random, introducing ECO fans into the discussion 

Phil

Composting bogs next 

[Phil Ambrose]

On ‎24‎/‎06‎/‎2017 at 10:11, nb Innisfree said:

Several years ago during a very hot spell we were moored next to a white painted  steel narrowboat,  The difference in roof surface temp between the two boats was remarkable, our dark green surface was unbearable to touch, literally hot enough to fry an egg on whereas the white boat actually felt cool. 

And that's why I changed my roof colour from Raddle Red to Dove Grey, a huge difference 

Phil

1 minute ago, mrsmelly said:

Composting bogs next 

Looking forward to that

Phil

[RD1]

In the days before aircon, Land Rover had a white safari roof on their vehicles for warmer climates. 

Basically it was a white aluminium roof that sat with an air gap on spacers an inch or so above the original. 

A white tight tarp placed over the canal boat roof could have a similar effect.

When we used to camp, we had fresh milk, so a bowl with an inch of water in, and a "T" towel draped over the milk bottles, meant the towel was always wet, and when placed in the windiest place, in the shade, say under the car or caravan, dropped the milk temperature a fair few degrees. Basic Physics, more efficient with more airflow though.

In the 60's there was also a water evaporative fridge you could buy, pour a pint of water into a hollow on the top and a cool fridge ... sorted. 

 

Last week, when the heat was too hot to stand... we came home lol. Drove home in an air-conned car, switched on the portable aircon unit in the bedroom... bliss.

Edited July 2, 2017 by RD1

[Phil Ambrose]

7 minutes ago, RD1 said:

In the days before aircon, Land Rover had a white safari roof on their vehicles for warmer climates. 

Basically it was a white aluminium roof that sat with an air gap on spacers an inch or so above the original. 

A white tight tarp placed over the canal boat roof could have a similar effect.

When we used to camp, we had fresh milk, so a bowl with an inch of water in, and a "T" towel draped over the milk bottles, meant the towel was always wet, and when placed in the windiest place, in the shade, say under the car or caravan, dropped the milk temperature a fair few degrees. Basic Physics, more efficient with more airflow though.

In the 60's there was also a water evaporative fridge you could buy, pour a pint of water into a hollow on the top and a cool fridge ... sorted. 

 

Last week, when the heat was too hot to stand... we came home lol. Drove home in an air-conned car, switched on the portable aircon unit in the bedroom... bliss.

The idea of the white tarp reminded me of some advice that I read pertaining to cruising the French canals, the advice was to have a white sheet of some sort that could be tied to the hand rails and to the bank to provide shade. Never tried it but assume it would work.

Phil

[mross]

Evaporative cooling works OK when the humidity is low.  Does not work at all when humidity is high.

[Giant]

Someone over on the DBA forums was reporting good results in France from using a small water pump to bring water up from the canal/river and running it over the roof of their barge.

I would be tempted to try it on ours, but the water here is dirty and brackish. On a cleaner inland river I'd try it. Maybe with a long pipe down the centreline and holes drilled in the sides at intervals.

[cuthound]

10 hours ago, blackrose said:

I know a bloke who made loads of small holes in a couple of hoses and laid them on his roof to constantly spray his boat with water. The hoses were fed from the mains water supply at his mooring. Wasteful yes, and he soon discovered it made absolutely no difference to the temperature inside the boat.

I'm surprised, evaporating any liquid will increase cooling and is how conventional fridges work. Think of the cooling effect of spaying a deodorant onto you. Also as I said in an earlier post,  in exceptionally hot weather spraying the condenser of fridge plant was the difference between losing the building due to overheating and keeping it on air.