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c.kvilums

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Reply with quote  #1 

recent research has indicated that HVAC systems (heating, ventilation and air conditioning) contributes to approximately 62% of the energy consumption of auxiliaries on board. 

I am currently investigating how solar and wind energy can be used to support these systems however, weight has a considerable role in the performance of vessels and I would like to ask the members of this forum as to whether they have investigated the use of lightweight solar collectors? Is this even possible? What sort of challenges may I face when considering light weight solar collectors?

I look forward to reading your opinions. 

Garage_Hermit

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Reply with quote  #2 

Hi, I am not a marine engineer or anything, but I would not necessarily look to *solar* energy for "supporting HVAC"

I mean, a ship has an enormous powerplant so space heating (by air or by water), and domestic hot water are not, in my layman's view a big problem... A ship probably WASTES more hot water from its steam turbine, than me and all my neighbours put together, could get through in five years !

Nonetheless,  everything is relative, and I supposed we *are* suppose to think green these days, and no doubt you are looking at downsizing ancillary equipments, in order to make lower demands on the prime mover in the 1st place, so that is good for the planet , I guess !

(Using the aircon on my car increases the fuel consumption by 10 percent !  but so does having underinflated tires !)
(Many cars in Europe now come with two batteries ! because one is not enough, there's so much electronics on vehicles !)

Since I have (apparently) a problem getting my head round our "classic" solar techniques of thermosiphon, I propose to ignore those approaches for onboard ship, and that just leaves you with PV (photovoltaic).

(By the way, I fail to see how WEIGHT is going to be an issue (except an academic one, that is...): designing a system for use aboard a 80,000 ton vessel, would make it a twenty-ninth order priority, in my view...)

Apart from PV, not many options, therefore... Well, YOU COULD install a solar furnace, but it would be tough - on land they require tens of hectares, and loads of computers to focus the mirrors on the lens (normally a very HIGH tower), so on a ship, that just does not bear wasting brainpower on !)

(at last for another 20 years I guess...)

I ought to state, I have zero experience with PV - try visiting the PV section of this site and brainstorming with some knowledgeable folx on there...

OK, you could install a square mile at least of PV panels on a good-sized container vessel, and in addition, drive around or across the tropics - wow !

However, the biggest problem wth PV would be SALT !  and atmospheric muck, not to mention CARBON from the ship's exhaust stack...
You *could* install electrostatic systems to help, but that is even *more* expense...  On land, cleaning of PV is a nightmare that nobody who buys them ever thinks of - most folks can't do this job themselves (safety, roofs ladders, accident insurance etc.) so cleaning of PV is becoming a GROWTH INDUSTRY... I would say, is the biggest problem with it -- if you DON'T clean, then efficiency drps off REAL quickly... At least in the industrial areas where most of us live - in the country, you might get away with it, but what about FARM DUST (after harvesting etc...).

So cleaning PV will be a genuine headache - you would need robot systems to do it - corrosion sensors, salt eliminators, water jetters, spray gear, you could not put deck hands up there, in their normal shoes, to clean a thousand square meters of PV panels while transiting Cape Horn on a bad day... 

Anyhow, I hope you find this amusing, if not informative !
Here's wishing you luck in your endeavors,
Garage_Hermit
Port du Légué


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netttech

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Reply with quote  #3 
On land I support Solar PV because you receive power everyday. However, if you are talking marine vehicle....wind may be the better choice. The ship moving thru the water should cause a turbine to generate power.

The reason they make BIG turbines with Long blades is to catch as much wind as possible. On a ship I think a smaller blade turbine would work fine since the wind is created as the ship moves.

I don't know how much power you are needing, but there should be some mid range turbines available.

Jeff
Central IL 
SolarInterested

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Reply with quote  #4 
Quote:
Originally Posted by c.kvilums
recent research has indicated that HVAC systems (heating, ventilation and air conditioning) contributes to approximately 62% of the energy consumption of auxiliaries on board.I am currently investigating how solar and wind energy can be used to support these systems however, weight has a considerable role in the performance of vessels and I would like to ask the members of this forum as to whether they have investigated the use of lightweight solar collectors? Is this even possible? What sort of challenges may I face when considering light weight solar collectors?

I look forward to reading your opinions.


I would think that windmills could induce extra drag and costs. Solar panels might work but shading could be a problem as the ship's direction of travel (and orientation with respect to the sun) changes. Where would they be mounted?

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c.kvilums

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Reply with quote  #5 
Hi guys! 

Thank you very much for your responses to this question. I have been able to identify that PV technology can in part support a conventional HVAC system. In short I am trying to develop a hybrid system which can in part be passivly supported. In particular solar cooling is of interest to me and from my research into passive design, I have been amazed and suprised by some of the results. Which in some cases completely eliminates the need for conventional HVAC systems. 

Attached is a picture of a concept design, where a rigid wing provides the chimney for heated air inside of the solar chimney you can see on the roof of the catamaran. 

In addition to this I have changed the internal general arrangement so that all major heat gain sources flow towards this roof and constitutes to the stack effect which pulls air from the interior and inducing a ventilative effect. The incoming air is preconditioned thus creating a more comfortable thermal interior. 

I understand that this would only do in certain climates. But the idea of using solar energy to heat, cool, ventilate and provide electricity for auxiliaries intrigues me. 

What are your thoughts?


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jpeg Demonstration_Schematic_copy_4.jpg (1.06 MB, 122 views)

Garage_Hermit

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Reply with quote  #6 
Hi, I think I see (partially) what you are getting at !

Using heat to evaporate water, thus inducing a ventilation effect due to evaporation...

The first time I saw this was years ago, on vacation in Greece.... In the heat of the afternnon, the old lady I stayed with used to chuck a jug of water from time to time, onto the stone terrace in front of her door, to induce cooling and ventilation in the house, and it really worked ! 

In fact, it was so amazing, I never forgot about it, and I still do it at home here, to the bemusement of my wife when the weather is really too hot in the summer !  I axed around but my neighbours never saw this before, so I guess I am an oddball after all...

The quantity of water does not need to be too great, one has to experiment !  I open the patio window wide, and chuck a few liters of COLD water onto my front (downstairs) porch, it hangs around in the grooves of the deck for a while... thie evaporation effect pulls heavy air out of the house, to replace the "rising bubble of low pressure", air literally swoops out of my basement !  Then more air from my upper floors flows down the stairwell, (however the flow effect is not at all noticeable in this part of the flow path...). I guess it is on its way to fill in the other partial vacuum created in the lobby !   The most noticeable effect occurs at the kitchen door, where a GALE of incoming wind is produced ! I'd say (from memory) that the effect at the lower (puddle) door is LESS than at the upstream (passive) door...

Was never much good at physics, but this effect is really remarkble (-:

To give you some idea, the kitchen door is around ten linear meters off-axis from the water puddle creation point, and one floor higher, = 2.8 meters approx.
The volume of air involved would be pretty remarkable, I reckon, without calculating it - probably, guestimating, 10 X 2.5 X 4 = 100 cubic meters.  Guessing again, I would say that the incoming wind effect at the kitchen door is probably more than 150 liters a second (because I have a fan that generates this flow, and I'd guess that my "terrasse effect" is three times that of the fan... and the passage space at the door would generally be a lot smaller that at the patio door (about 3 X smaller...) (I have a technique !) The kitchen door is 2 meters something tall, by 0.7m wide (a narrow door, in fact) (must have been a strange architect...)

Obviously these are just rough guides to let U know the scale of the phenomenon.

There is another technique I have read about, but don't really understand, it is associated with the Trombe Wall, you could read this up on the web, it was invented by a Felix Trombe, a French solar engineer. Basically it is a passive heat store.
So what I am talking about, is using a Trombe Wall to *cool* a house, no doubt by some evaporative effect like what U are looking for - perhaps this could give you an idea to explore.  I am going to have to read this up myself, in fact !

By the way, Felix Trombe was also a very famous "spéléonaute" (speleologist / spelunker) , and this reminds me of ANOTHER phenomen of ventilation...  Which has not got much to do with marine, but with geology -- that is, the way that air rushes out of a cave-mouth.
Way back in my caving days, I was always amazed at the phenomen of WIND EFFECT generated in the mouths of (certain) caves - sometimes enough wind to extinguish one's carbide lamp flame !

Yet it dwindles down to nothing after a few metres !  In Italy I descended one cave in partiocular (over 500 meters deep) and I can assure you the wind velocity was astounding at the entrance !  Idem in England, with very little caves.  The effect does not occur in ALL caves, I guess it depends on there being a constriction of the right size and orientation, at a certain distance from the actual mouth, and that air conditions must be adequate (density, humidity etc.).  Bear in mind that air temperatures remain VERY constant in most underground caves...  (water temps also...).

That's enough for to day !
Bye,
Garage_Hermit

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Garage_Hermit

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Reply with quote  #7 
AIR CONDITIONING UNIT FOR CRUISE LINER - CONCEPTUALIZED DESIGN
=====================================================

I thought up a model to represent what I was describing in my earlier post about evaporation.

If interested, see enclosed PDF file.

Solar Regards to All,

Garage_Hermit

 
Attached Files
pdf SOLAR_AIR-CONDITIONER_CONCEPT_FOR_CRUISE_LINER.pdf (913.37 KB, 17 views)


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(1)  "Heat goes from hot to cold, there is no directional bias"
(2) It's wrote, "voilà" unless talking musical instruments...

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