If one is running a genset on propane AND generating electricity from solar panels at the same time, one could put the propane tank in a bath of water, with the chilled water pumped up to cool the solar panels (which would raise the water temperature) and return the water to the propane tank bath. This would help the propane tank and lines keep from freezing while delivering power and at the same time help keep the solar panels cool to maximize their efficiency.
But how often would one be both generating power from burning propane and generating power from solar.
A story: hobby steamboaters who use propane as fuel for their boilers often place their propane tanks in a water bath to keep from freezing and choking off the energy flow. Sometimes they also run a steam line to the water tank. And often that’s as far as they go---a manually operated steam line going to this tank to help warm that water. Unfortunately, in at least a couple cases, that manual control was forgotten about and the water temperature not monitored until the propane tank “vented” due to overpressure. And in each of those cases, the vent was not piped overboard and so the propane vented into the bilge and into the boiler fire leading to fire/explosion and man overboard. A solar/propane bath recirculating system wouldn’t likely run that same risk, but regardless, do please direct any propane vents overboard if using propane.
-mt
From: electricboats@
Sent: Sunday, August 08, 2010 11:12 AM
To: electricboats@
Subject: Re: [Electric Boats] Water Temperature
Bob,
I guess the silence is loud and clear, Ned gave an answer that while correct, only confirms that efficency is extremly low and this is based on the use of water at a certain temperature as both the source and sink. The phrase "slow boat to china" comes to mind :)
My idea of a waterfall thrugh the keel didn't seem to go very well, but then most questions and answers have been revolving around small amounts of generation or recovery.
My thoughts about recovery of waste heat, or preventing overheating, involve the use of liquid propane as a sink (-44 degrees @ 0 psi) and if using a water surface temperature of 70 degrees, pressure will build to 110 psi.
Having a temperature delta of -50 > +1200 F is easy to set up and such a wide range will only assist in speed of cycle and not so much about how much energy is taken in.
The simple fact is, heat builds pressure and pressure produces work potential and mass flow equates to power.
With those comments I'll withdraw the subject and carry on with my work as best I can.
Cheers
Ron
--- In electricboats@
>
> Ron,
>
> One of my concerns has been how to utilize the excess heat generated under
> solar panels. Solar panels are very inefficient converting only 20 - 30
> percent of the energy falling on them to electricity and the balance is
> waste heat. Would love to find some way of capturing that waste heat and
> using it to generate more electricity.
>
> Bob Wilson
> Backpacker 38
> Building in Richmond, BC
>
> On Sat, Aug 7, 2010 at 9:13 AM, Ron <rlgravel@...> wrote:
>
> >
> >
> > I had hoped for a higher figure, but it is what it is :)
> > For me the line of thought started in the 60's watching Cousteau and
> > thinking about how neat to have a submarine and not need a surface support
> > team along with all the expenses and dependence on good weather.
> > Lack of funds and a dedication to family has held it to only dreams, but
> > along the way (I'm a slow learner) I have picked up thoughts based on what I
> > have used (physically and mechanically) in several different lines of work,
> > but almost always my focus of thinking was how to save wasted heat or make
> > use of it.
> > The results of all those years of thinking has led to many possibilities
> > about picking up crumbs of wasted energy and recovering mechanically or
> > generating small amounts of electricity, this has been the focus of so many
> > post by this group (battery charging and regen methods) which all goes to
> > one basic word "Heat".
> >
> > Heat is all around us in many areas and the intensity varies quite a bit
> > from the water a boat floats in, to the hot exhaust pipes of an IC engine,
> > collecting heat is not a big problem but designing a machine to utilize the
> > heat collected, represents a challenge that most people will shy away from
> > for many reasons. I think charging batteries can be a 24 hours action and of
> > course always better when the sun is shining
> >
> > Before I go into any depth of conversation, I need to ask if anyone wants
> > me to continue or is this a taboo topic ? I will share a few thoughts but I
> > generally have a very hard time conveying my thoughts in a manor that is
> > easy for others to see and I do have some design work on-going, but have run
> > low on enthusiasm.
> >
> > Ron
> >
> > --- In electricboats@
> > Samuel Shallard <sshallard@> wrote:
> > >
> > > Not quite sure where this line of thought started but here goes.
> > > I line in ME
> > > Surface water temp in the ocean currently varies for 55-65 deg.
> > > I winter that will drop to the mid to low 30's. We may get freezing
> > > close to land.
> > > Water down deeper is 50 degrees.
> > > One thing that happens with tides is that on incoming tides the
> > > deeper water will upwell around anomolies such as ledge and bring the
> > > cold water to the surface.
> > > Interestingly if you get offshore into the Gulfstream the water temp
> > > jumps into the 70's
> > > There are web sites with the information on buoys that giver surface
> > > water temps and temps at depth for the gulf of ME and probably most
> > > of the US.
> > > Most changes in temp in lake water occurs in the top 20 ft. Out lakes
> > > vary a lot depending on depth and whether they are spring fed.
> > > Groundwater is usually 55-60 degrees so spring fed lakes may stay on
> > > the 60's while surface water fed may be up to 80 degrees. Around here
> > > they all freeze in the winter.
> > > On Aug 6, 2010, at 4:48 PM, Ron wrote:
> > >
> > > > In general I think there is an average temperature of surface
> > > > water, but I'm wondering what kind of difference there is from warm
> > > > to cold represented by the members of this group in their different
> > > > locations ?
> > > > Also how much of a change with the seasons ?
> > > >
> > > > Thanks for any feed back.
> > > >
> > > > Ron
> > > >
> > > >
> > >
> >
> >
> >
>
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