Plastic Shipping Container For Hot Water Storage

[WStayton]

Ronmar:

   Something dpesn't add up in your numbers . . .

   You say:  " .125 gallons per KW/HR is a pretty close estimate for fuel consumption"   Diesel fuel is 6.7 lb/gal, more or less, and I kW-Hr is .746 HP-Hrs, so  that works out to a BSFC of 0.624775
lb/hp-hr, to put it into numbers that I mean something to me.  My Mercedes OM616918 has a published BSFC of 0.48 lb/hp-hr. Since the Listeroid truns slower than the Mercedes and fluid friction, which is most of the internal friction of a diesel engine - two surfaces moving relative to each other with a layer of oil in between, the Listeroid SHOULD have BSFC lower than the Mercedes, other things being more/less equal - they are both indirect injection, the Mercedcs has an OHC while the Listeroid is pushrods, but that should be only a small (2% max) differance . . .

  You seem to agree that 1/3 of the total fuel load goes into the cooling water and you seem to agree that another 1/3 goes into exhaust heat+engine jacket+oil+..., so I think that you are agreeing that i/3 of the heat in the fuel also goes into power output, no?  Well, if we have 12.33 hp made from 1/3 of the heat in the fuel, then we must be using 12.33 Hp-hr X 2545 BTU/hr = 313, 861 BTU going into the water each hour from the electricity.  If the HP is 1/3 of the total heat energy output of the engine, we must have 3 times that all together going somewhere - so the total heat energy out put of the engine is 941,583 BTU/Hr.  Using 140,000 BTU/gallon, we should thus have a fuel consomption of  140,000 / 941,583 = .67 gallons per hour.  So, Jens, what is the fuel consumption of your engine?  I'm betting it will be between the two numbers proffered above, but closer to mine - any takers on that bet?  <grin>

Crofter:

  I was thinking to bevel the mating edges at 45 degrees, and then apply my "scab" over that.  I realize that isn't a true scarf joint, which would be at more like 15 degrees, but it is BETTER THAN A BUTT joint, no? My table saw, and my table saw skill, limits my joints to something more than 15 degree angles, and rather than make it a 30/60 joint, which is about the limit of what "I" can cut, and then have all of the monkey-motion of trying to make it a good fit, I went simple and opted for 45 degrees.  Time will tell, whether this is a good, or a bad, decision!  <grin>

  About the joint being stronger than the materials - that is one of the reasons that I thought that I should use marine plywood, at something like three times the cost of exterior plywoood, since marine ply does have better gluing - both in technique and materials.

   I have seen some marine plywood that has been tested to failure, and it did NOT fail along the internal glue joints, FWIW.

  About drying/wetting making it weaker - that is why I was thinking to paint/prime the whole structure, interior and exterior and what kinda surprised me about Solar Gary's "tank" - it didn't look like he painted it at all, even though he was burying part of it in the ground.  Paint/primer won't COMPLETELY eliminate swelling/shrinking but I think it will diminish it by at least a factor of ten!

Thanx for the input guys - all contributions greatly appreciated!

Regardz,

Wayne

[Ronmar]

Ronmar:

   Something dpesn't add up in your numbers . . .

   You say:  " .125 gallons per KW/HR is a pretty close estimate for fuel consumption"   Diesel fuel is 6.7 lb/gal, more or less, and I kW-Hr is .746 HP-Hrs, so  that works out to a BSFC of 0.624775
lb/hp-hr, to put it into numbers that I mean something to me.  My Mercedes OM616918 has a published BSFC of 0.48 lb/hp-hr. Since the Listeroid truns slower than the Mercedes and fluid friction, which is most of the internal friction of a diesel engine - two surfaces moving relative to each other with a layer of oil in between, the Listeroid SHOULD have BSFC lower than the Mercedes, other things being more/less equal - they are both indirect injection, the Mercedcs has an OHC while the Listeroid is pushrods, but that should be only a small (2% max) differance

That is why I made an earlier comment about you applying the direct conversions to these equations, they do not take into account real world drive and generator efficiency losses.  Your BSFC numbers are for the ENGINE output in KW.  The real world fuel consumption figure I provided is for the generator electrical output in KW, not the engine.  It should be about 80% or so more than the engines raw BSFC.  When you get your generator on line, I am guessing you will encounter similar fuel consumption figures.  I have encountered comparable numbers with the few onan(kubota diesel engine) diesel gensets I work with.

  You seem to agree that 1/3 of the total fuel load goes into the cooling water and you seem to agree that another 1/3 goes into exhaust heat+engine jacket+oil+..., so I think that you are agreeing that i/3 of the heat in the fuel also goes into power output, no?  Well, if we have 12.33 hp made from 1/3 of the heat in the fuel, then we must be using 12.33 Hp-hr X 2545 BTU/hr = 313, 861 BTU going into the water each hour from the electricity.  If the HP is 1/3 of the total heat energy output of the engine, we must have 3 times that all together going somewhere - so the total heat energy out put of the engine is 941,583 BTU/Hr.  Using 140,000 BTU/gallon, we should thus have a fuel consomption of  140,000 / 941,583 = .67 gallons per hour.  So, Jens, what is the fuel consumption of your engine?  I'm betting it will be between the two numbers proffered above, but closer to mine - any takers on that bet?  <grin>

Wayne.
1. I think you have a math error in there.  12.33 X 2545 is 31,380, not 313,861.
2. I fully agree that 1/3 of the fuel/BTU consumed exits thru the cooling system, as I have carefully measured it on my system.  Where the other 2/3 go exactly I do not know as I have not built my exhaust heatex yet...
3. You can NOT possibly get more energy out than you put in, Sorry, I don't make the rules:(
4. And again, your use of these equations does not take into account real world efficiencies.  For example, a good well proven rule is 2HP per electrical KW for SUSTAINABLE power generation.  This rule takes into account real world drive and generation efficiencies.  With that in mind, using your numbers, that 12.33HP/HR equates to 6.17 KW/HR.  Now in this case since we are talking electric heating elements in water, which is a much more known conversion process, the standard conversion for KW to BTU is probably not far off the mark.  So 6.17KW/HR X 3414 BTU = 21,047 BTU/HR into the water from the electricity generated with 12.33 engine HP...

[LowGear]

I vote for one tote Mickey Moused to your engine and see where it thermosyphons to in 4 hours of loaded operation.

Casey

[WStayton]

Jens:

  I sort of disagree that it takes 2 HP to make 1000 watts of power - that would mean that your method of power generation is only getting about 2/3 of the power that the engine is generating turned into electricity.  If you are losing a third of the power your are making, something is WRONG!  I believe that the "2 HP = 1 kW' was dreamed up to cover the fact that if you have a spark ignition engine, in all probability you will be operating below the torque paek of the engine, so if you are at full throttle, i.e. 100% of available torque, adding .01 more HP to the requirement will cause the engine to slowly fold it's tent and quit! I also think that the rule of 2 HP per kW was introduced to allow some relief from running the engine at 100% and having it spit parts, though that is probably less of a problem with a Listeroid than with a more modern engine.

    I think that I will have some losses in my setup, that was the principal reason that I wrestled with whether or not I should put a transmission in the drive train.  Adding that transmission, takes about 5%(my guess- no known data that I could find) of the through power to overcome its internal fluid losses, etc, when it is in high gear at 1:1 gear ratio.  If I have to use it in 3rd gear, the loss will be more like 10%(again, my guess - no published data that I could find) of the trough power.  And, yes, there are some power losses in the lovejoy coupler that I intend to use, but those are more like 2% of through horsepower.  The only other losses I will have are the bearing friction and cooling losses in the generator.  Nobody publishes ANYTHING that even gives you a hint of what these losses are, but a rolling element bearing isn't going to be a real energy hog since you can walk up to a runing bearing and put your hand on it and NOT get FRIED, and if it is eating energy it must be getting changed into heat, there isn't any place else for it to go.  So, maybe another 2% for the bearings (generous I think but . . .)  The only other load is the cooling fan, and it doesn't appear to me to be a real hungry appendage - I would be very surprised if it was 5% of the rated power of the generator-head.  So, if I am operating in fourth gear, there is 5% + 2% + 5% = 12%, which is a far cry from 33%  Note: these are all predicated on operating at max power ie, the power loss is pretty constant - the bearings and the transmission and the fan don't care what power you are making, they have about the same load, no matter what.  So, if I am losing 12% of the rated generator capacity, I have a waste load of 24kW x .12 = 2.88 kW, so will need another apx 3.9 horsepower.  Since I don't think it is prudent to run at more than 85% of available hp from the standpoint of engine longevity, and I only have about 32 HP available, if I only use 85% of them, I only have 27 to play with.  If the "friction" losses are 4 HP, I only have 23 left to make electricity, or 17 kW.  If I am putting in 27 HP at   0.48 lb / hp hr (per the engine manufacturer), for a fuel consupmtion of 12.96 lb/hr. If I put in 12.96 lb/hr and get 23 hp in work, my "apparant" BSFC is .56, which is still substantially less than the apparent BSFC for your Listeroid, per Ronmar, which should be a more efficient engine than my OM616918.  Unless you have a fluid coupling between your engine and your generator, the energy must be going somewhere and it almost certainly must be heat if it isn't electricity, and it isn't 33% of the power that the engine makes!

   Energy is neither created or destroyed (unless you do nuclear fission/fusion, and then, e=mxcxc governs the energy flow) it must be going somewhere and it almost certainly is going there as heat - so, where is it?  I don't believe that it takes 2 HP to make 1 kW of electricity, sorry!

  I don't mean to be argumentative, but some things just don't stand engineering scrutiny(sp?). <grin>

  By the way, what IS your fuel consumption while you are making 9200 watts?

LowGear:

  Umm . . .there isn't really any way that I can do that, since the engine uses a pump for coolant flow through the engine, and there is another Jabsco pump to push raw water through the heat exchanger, so what you suggest isn't really possible without eliminating several parts in the system that SOMEBODY thought were necessary!  I don't think they put ANYTHING in/on the engine just because it was pretty!

  That's my story and I'm sticking to it! <smile>

Regardz,

Wayne Stayton

[Ronmar]

Wayne, if you do a little internet searching of generators up to say 50KW or so, you will find pretty consistently the 2HP per KW rule is applied.  Above 50-100 KW the ratio typically drops a bit bcause the ammounts being dealt with are so large. I have run a lot of powerplants, some propulsion sets up to 3000HP and even those held pretty close to that rule(1.5MW).  The 15KW onan sets I work with now at my remote sites have, you guessed it, a 30HP kubota diesel...  You might be able to get away with less for a little while, but for reliable/sustainable power, there is a reason 2hp is used.

How many of your own KW have you made?  I am guessing not many...  Like suggested, power up your genset, wire up some load(baseboard heaters from surplus center work great and are cheap) and plumb on a barrel or one of those totes, and start making power and measuring fuel, heat and load.  We can throw numbers back and forth and burn bandwidth till we are blue in the face, but untill you have done it yourself, it reaches a point where we who have, and have TAKEN DATA are just wasting our time...  Good luck with your project...

[Crofter]

"I don't mean to be argumentative, but some things just don't stand engineering scrutiny(sp?). <grin>"

Wayne, throw that calculator away; it is making you blind and deaf!

Raw data calculations are not a whole lot more worthy than astrological predictions if they ignore (or are ignorant of) field conditions that can often greatly modify the outcome. It is amazing how easy it is to get blindsided by some of them.

[mobile_bob]

been too the land of Oz (kansas) moving, thus i am late to this party

here is my .02 worth on the topic (er rather the discussion on hp vs generator output)

the 2hp per kw generated thing is a carry over from the gas engine days, and remarkably it seems to work
fairly well for most diesel engine's as well.

in my opinion the reason it works for diesels too is largely based on folks not running their engine right up against rated hp
for long periods of time, the differences in manufactures hp claims, or some combination (or all) of these and other factors.

it seems to hold fairly true as a rule for the listeroids, while it is not so clearly so with the S195 changfa

the changfa is rated at 12hp continuous and 13.2 hp for a one hour rating, which might indicated that it ought to only make
somewhere between 6 and 6.6kw electrical. the reality is it will comfortably make better than 7kwatts continuous and over 8 on
a one hour rating, however...

the limiting factor is the cooling system, if you stick with the hopper cooling you will likely be limited to 6-6.6kw electrical output
to assure proper cooling and not have excessive water use. on the other hand with a water pump, radiator, t/stat, pressure cap etc
the engine will have assured cooling and can make more kw output based on the factory rated hp.  but...

the bottom line is knowing for sure what the hp rating really is, therein is the problem
too many factors have a marked effect on hp, everything from differences in manufactures rating (from conservative to optimistic), differences in fuels, elevation, timing, intake and exhaust, injection quality, and other factors including the cooling systems ability to
maintain stable engine operating temps.

the following is from many hours of testing a number crunching

the s195 is about 31% efficient at converting diesel btu's to kwatt output
the st7.5 single phase head is about 78% efficient at taking this mechanical power and converting it to electrical power
about 32% of the waste heat exits the cooling system
about 28% of the waste heat exits the exhaust
the balance goes out with convection, radiation, production of noise (lots of noise) and via the lube oil
Vbelt drives are about 2% loss if designed properly, serp about half that if done right
all of the coolant rejected heat can be harvested and used if done right with a t/stat and pump, while only about
75% of the available waste heat from the exhaust should be harvested and used, otherwise the exhaust gasses will condense
and create other issues.
the s195 direct driving an st7.5 can produce right at 10kwatt/hrs of power for each gallon of pump diesel consumed, this only if the cooling system is such as described and the engine is ran at max output

for whatever it is worth, and your mileage may vary

bob g

ps. i have also found reference in a couple of places to the use of another formula for calculating generator output
for a diesel engine,
take the amount of power needed in KWe and divide by 700, the result will be the amount of engine hp needed to produce this
amount of power. 
while it comes closer to explaining the changfa it is not quite right either, so perhaps divisor shifts from maybe 600-700 depending on
engine type?

[WStayton]

One brief comment and then we'll leave this issue!  <smile>

 One loss that I have been stumbling over and had my eyes too focused on other things to see, and I am surprised that nobody else said something, is the heat loss of the generator proper.  It is, I am sure, proportional to how much electricity you are making and I'm also pretty sure isn't accounted for in the horsepower requirements.  I've got no idea what the amount truly is, and the "scientific" way to measure it, sticking the generator in a calorimeter full of water, will make MANY more problems than it will solve.  Any generator that I have ever put my hand on has been at least warm and some were actually "hot", so I am sure that it is a significant heat loss, and the big dummy ("ME"! <grin>) was so busy beating on everybody for "looking the other way", that I completely missed/ignored it.

  As to the beating on everybody to do things the "scientific" way:  If sort of bothers me, being of a more less, orderly and thoughtful frame of mind, to see folks who estimate things by looking at the entrails of sheep, or the direction that the moss is leaniong on the side of a tgree where a dog has just pee'ed (sp?), but if you guys want to do things that way, far be it for me to try to introduce order and methodology into your world.  I am curious, in fact some would say obsessed, to know the how, where, why . . . of things mechanical, but I do realize that some people prefer to just view the world as a set of "black boxes" that they twist dial "A" and result "B" occers, and they couldn't care less about why!  So, I apologize foir trying to impose MY way of looking at things on everybody else - not everybody sees the world the way that I do, and I guess that is a good thing - if everybody looked at everything the same way, we would all drive the same autumobile in the same shade of gray with the same powertrain, etc., etc.

 So, if I offended anybody, I am sorry, and I will make an effort to keep my "everything has to have a measureable, and accountable "reason for being" way of looking at things out fo everybody's face.

On that note, how about we close this thread out - we've learned all that we need to about using shipping containers for hot water storage!

Again, thaks for your input - whether I agreed with it or not!

Regardz,

Wayne Stayton

[Ronmar]

  As to the beating on everybody to do things the "scientific" way:  If sort of bothers me, being of a more less, orderly and thoughtful frame of mind, to see folks who estimate things by looking at the entrails of sheep, or the direction that the moss is leaniong on the side of a tgree where a dog has just pee'ed (sp?), but if you guys want to do things that way, far be it for me to try to introduce order and methodology into your world.  I am curious, in fact some would say obsessed, to know the how, where, why . . . of things mechanical, but I do realize that some people prefer to just view the world as a set of "black boxes" that they twist dial "A" and result "B" occers, and they couldn't care less about why!

Wayne,  I am very much the same way, and I have used many of those very same formulas to properly size components, or determine if my hairbrained scheme of the day is even feasable(never have found entrails or dog pee very usefull).  But over the years I only continue to use the ones that I have proven thru experience to reasonably reflect reality...   Get yours running, convert/transfer some energy and you will see what we are talking about...

[LowGear]

Brainstorm alert on the EDPM thread concerning containers.  Stay tuned and we'll reveal the truth right after these messages.

Casey

[mobile_bob]

the problem with trying to do everything with formula and calculations is mainly with the fact that most folks eyes glass over long before
you get far into the weeds.

i am as guilty as anyone when it comes to trying to use scientific method and math to explain what i am either planning or observing with
experimentation.

what i have found to be most useful is the use of established methods and formula as a starting point to try and size components as close as i can to start with, then follow with carefully controlled experimentation with good instrumentation to see how close the reality is to what the math predicted.

once i get a sufficiently large body of data certain patterns emerge and replication of results start to also become apparent.

then i can go back and recrunch all the numbers, rerun all the calculations and tweak the constants to get an accurate set of formula that will allow me to predict with some degree of accuracy the performance of a specific engine/generator package under a specific set of parameters, using a specific fuel , at a specific set of load points etc. etc. etc.

what is key is coming to an understanding of what is happening, and being able to then lay out all the details so that someone elsewhere can replicate the same results using the same equipment under the same conditions.

you know you have it right when you can take the data and develop a logic problem to prove the results you are seeing.

as an example you know you are correct when you can prove through logic that your genhead is for instance 78% efficient and the engine is 31% efficient at a specific load when altering either efficiency would skew the other far outside what is likely for the opposing unit.

Ronmar and I have discussed and developed formula to predict the BSFC of a 6/1 driving an st5 across its output range to a high degree of accuracy a couple years back on another venue/forum.  it takes a bit to get there and was only developed after we got a few data points established by careful observation/experimentation using good instrumentation.

in my opinion there are only a handful of folks that are really interested in working out detailed testing/ developing formulas and all that, however there are a few that are quite passionate about it, and once the formula is developed there are many more that will use it.

so in the end the result is generally always worth the effort.

also for what it is worth, there are at least a few published sets of data on commercially available generator sets and some cogen's
in the 4, 7 and ~12KWe class,
those sets of data are very useful as bench marks to compare to, you know you are doing well when you start to get close to the BSFC numbers the big boys get on their units, and really starts to get exciting when you can achieve better numbers than some of them
who's units can cost from 12k bucks to well over 30 grand.

also for whatever it is worth

it is a very good genhead (single phase) that can achieve 80% efficiency in the <10kva class, generally only the most expensive heads
can even come close and only at or near rated load.  for an ST head the 78% number is likely very close to reality for most of them.
single phase heads don't get over 80% until you get up to or over 50kva or so, or spend over 2 grand for one.  the losses seem to manifest mainly in heat, although there are some windage losses as well.

the rule of thirds is close enough for rough discussion when it comes to diesel engine's however the reality is likely quite different

the S195 changfa idi is about 31% efficient at best, while the 6/1 listeroid is in most cases no more than 28-29% efficient as generally deployed (but can be improved with better coolant temp control and a few other mods)

it is also very likely that either engine as used is likely much less efficient due to shifting, things like timing, leaky valves, slobbering injectors etc will reduce efficiency significantly over time, and this can be aggravated by alternate fuels and lack of proper setup and/or maintenance.

i mentioned earlier (and it might also have been noted by others) that the drive efficiency of a V belt can be about 98% (2%loss), but can be much worse if you don't follow good engineering and use quality components (pulleys and belts) losses over 5% can result.
generally serp drives do better if only because the engineering is generally worked out by someone else, the lack of cheap options also helps to keep the efficiency higher,,, generally speaking.

at the end of the day, if one is to get into serious testing, following scientific method, he will need some good instrumentation that is easy to use and interpret. things like a gram scale to measure fuel consumed, a watt/hr meter, a good thermometer, stop watch, load bank,  volt, amp meters to name a few.

there are good electronic gram scales that won't break the bank, quality thermometers are also fairly inexpensive, and those electronic
kwatt meter heads can be programmed to read watt/hrs with very good and repeatable accuracy, they too can be found very inexpensively on ebay from time to time.  load banks can be made up of surplus kitchen range heating elements, space heaters or any number of other methods.

an insulated coolant tank to measure recovered heat from the coolant system is also useful as is another for the exhaust if one is going to
try and recover exhaust heat and use it.

this is a topic i really like, even though it is getting astray of the OP topic a bit

bob g