is that from the lubrication system of an engine
i found a reference this weekend to the typical heat available from the hot oil in a diesel engine, being approx
2.5% of the btu value of the fuel burned
so in a typical changfa 195 where we are burning ~1 gallon per hour at rated load,
135000 btu/gal x 2.5% = 3375btu's
because of the design of the engine, the vast majority of this heat must be dissipated via radiation rather than
through the coolant, allowing us the ability to tap into and harvest this heat.
aside from the obvious benefits to oil cooling for this type of engine, the added 3375 btu's of recovered heat raises the
overall efficiency of a well designed cogenerator by nearly 4%. in a well shielded and insulated engine this number seems likely.
3375 btu's is a bit less than 1 kwatt of heat. (988watts) that alone equates to about 5-6 gallons of domestic hot water per hour
which is enough to wash dishes with, or take a quick shower... not bad for a heat source that is generally not considered by most
of us.
certainly seems like something that warrants investigation to me.
this is probably most appropriate for those engine's that make enough heat into the oil to even make it worthwhile, my thinking
is that most lister/oid types don't fit this catagory as the crankcase never really warms up much in service.
bob g
my 195 based trigen is going to also be fully enclosed, because it has a compressor
and i have the valving to covert it into a heat pump as well, in the winter months the enclosure
will be closed and all heat will be pulled out of that enclosure.
the heat in the lube oil is a high quality heat that for most of the year needs to be disposed of anyway
so the idea is "why not put it to good use"
because the changfa has an oil pump, and i will be incorporating a full flow and bypass filter system,
the ability to insert a small exchanger would be quite easy.
also it is fair to note that i plan on the reintroduction of the cooled oil to be fed directly into the gear train
in an effort to quiet those notoriously noisy gears that changfa type engines are known for.
bob g
Hi Bob,
IMHO.....
When a water cooled engine is running, the heat from the oil is already dissipating (and mostly captured) somewhere.
Typically the oil heat is conducted through the engine parts/block and ends up in the cooling system.
So in effect the heat from the oil is already being recovered by a water cooled engine.
If you add an oil cooler of sufficient size to capture the 3K btu's that you mentioned, you may actually reduce the btu's captured by your cooling system by that same amount.
Perhaps the only additional oil heat that one might capture is the heat that would have been dissipated from the none-cooled part of the engine block which normally heats the ambient air. I your case, a complete enclosure would capture that heat.
veggie
Veggie:
i would both agree, and respectfully disagree with your assessment
i would agree that a significant amount of heat is taken up by the cooling systems in most designs, however
the changfa or other chinese variants separate the oil from the cooling system fairly effectively, in that the oil is returned
via the drainback passages which does not allow for close contact to the water jacket.
also when you operate the engine up to near max rating, or in my case beyond that rating there is a large amount of heat
being transferred to the oil and the only way for it to be dissipated is largely through the castings and steel oil pan.
i don't think there would be much if any benefit of heat available at low or part load, but there is a significant amount of heat
a full load, and if we are to abate geartrain noise i for one will be fitting the engine with closely fitted insulated shields, effectively
cutting off most of the radiant heat transfer as well.
my little toyota 2 liter diesel pickup even has an oil cooler, it is non turbo and still the oem engineers figured it needed to have one
likely to remove heat from the oil under heavily loaded conditions.
i would also like to point out, the oil heat if it is to be transferred to the coolant, must have coolant with a lower temperature
if i am to try to get the oil down to 180 degree's F, i certainly cannot expect the cooling system that is running at 207-215 degree's F
to do anything toward that goal.
my opinion only
bob g
You would want the coolant returning from the radiator/heat exchanger to pass thru the oil cooler first. My coolant returns from my heatex at sub 100F temps. My only concern would be with not allowing the oil to get warm enough. On an engine that is ran daily, this is not a big issue. But on an engine that is in backup service, moisture drawn in thru the crankcase breathing is an issue. When ran, you need to maintain oil temp at a high enough point to allow that moisture to evaporate out of the oil and be exhausted from the case. In the case of my lister, it takes a lot of running to get all that oil down low up to temp. I have contemplated a small cappilary line off the end of the bearing oil feed pipe that runs up to the rocker arms and drips oil into those oil holes. this would be accompanied by a second small oil line drilled into the side of the head to take the dripped oil away from the head when it reaches the top of the valve spring cups. this oil could be returned to the camshaft end bearings. This would serve several purposes. One would be an easilly identifiable way to see that the oil is pumping. No drip drip into the rockers means the pump has quit. Another would be consistant a consistent rocker lube oil film. And last, but not least would be to add some heat from the head to the oil as it passes thru...
Even with an oil cooler in the loop, I think there is still a significant ammount of oil heat lost thru the pan and non cooled portions of the case as Veggie points out. An insulated enclosure with a radiant plate type loop or perhaps something like a A/C condenser or oil cooler panel in the vicinity of the oil pan might be an effective capture device. Cast Iron oil pan? Braze a copper coolant loop to the oil pan... Heat flows to cold. With an insulated enclosure, the coolest place for the heat to flow to then becomes the 195F coolant loop and the oil cooler being fed with lower temp return coolant, instead of 70F room air...
i have been considering soldering a copper tube loop to the oil pan and then cover it with the insulated shield
this particular application s195 trigen is slated to run a minimum of two one hour runs per day, it takes less than 5 minutes to be at full
operating temperature under full rated load, at which it will be running 90% of the time.
as for a lister/oid, i would concur re the issues of overcooling and not allowing the oil to heat up enough to boil off moisture, most of
those engine's don't generally run long enough or hot enough as it is to keep things dry down below, at least not enough so that i would
feel comfortable taking any btu's away from the oil.
bob g
There are a couple of people on this forum running their engines in an enclosed space (Jens is one). After a reasonable amount of running the engine vapours and general crud build up and coat everything with a dirty, oily film.
This is not a good environment for a heat exchanger. A radiator style system would clog up in no time. A coarse, coiled loop of tubing system might fare better but will still need frequent cleaning to keep the already reduced efficiency up (relative to higher surface area designs).
Consider maintenance too – an enclosure and other bits of kit in the vicinity of the engine just get in the way of servicing and repairs. If you do install heat reclamation from within the enclosure, think about how you can easily remove it for servicing and maintenance work. They also tend to be a little bit fragile (easy to bend / break) and so should be away from anything that might hit it.
Temperatures inside my acoustic hood are fairly consistent (no heat reclamation intended from inside the enclosure) at about 50 – 70 C. the oil runs at about 70 C so even without heat extraction, the oil will not evaporate off any water in the sump. The water thermostat operates at about 90 C and temperature measurement of the head shows the temperature does not go much above this – even at the end of a 48 hour continuous run.
I am not convinced there is much to be gained from enclosure (or oil) heat extraction but this is just my 2p worth and YMMV.
Regards,
Ian
Quote from: mobile_bob on January 22, 2010, 06:38:34 PM
i have been considering soldering a copper tube loop to the oil pan and then cover it with the insulated shield
this particular application s195 trigen is slated to run a minimum of two one hour runs per day, it takes less than 5 minutes to be at full
operating temperature under full rated load, at which it will be running 90% of the time.
as for a lister/oid, i would concur re the issues of overcooling and not allowing the oil to heat up enough to boil off moisture, most of
those engine's don't generally run long enough or hot enough as it is to keep things dry down below, at least not enough so that i would
feel comfortable taking any btu's away from the oil.
bob g
Hello Bob,
That idea would work. When the S195 is loaded it oil gets ot a pretty good temp. When I was doing some load tests on my gen-set a while back I did take some temp readings and I wish I recorded them. The oil temp was brought up very quickly. With my S195 being hopper cooled I did notice the oil temp rising much quicker much quicker than the water temp. I also know the oil does get hot enough to boil off moisture. Which is a good thing. It would not be that hard to wrap a coil around the S195 oil pan and have it soilered on. If people don't have the experiance to solder that much copper on steel I bet a good radiator shop could do it for a reasonable price.
I feel a fair amount of heat could be extracted from a setup you are desribing.
Henry
i think it gets lost in the verbiage that i am referring only to the changfa style engines, and not the lister/oid engine
as far as i can tell the difference's between the two are more numerous than are the similarities, very much
and apples to oranges thing when it comes to just about anything one wants to discuss.
on a changfa style engine one can control the vast majority of the fumes that would serve only to clog up air/air or air/water
exchangers that might be included in a containment system, however Ian makes a good point that accessibility should be
a forethought and not an afterthought with such a design.
maybe in order to mitigate confusion, i should move this topic to the changfa board?
bob g
From what I'm following, we want to keep the temp up on diesels using WVO & alternative oils.
So would pulling the heat out of the crankcase oil be counterproductive?
Quote from: Jens on January 23, 2010, 10:14:30 AM
Quote from: WGB on January 23, 2010, 10:08:18 AM
From what I'm following, we want to keep the temp up on diesels using WVO & alternative oils.
So would pulling the heat out of the crankcase oil be counterproductive?
I think you could pull all the heat you want out of the oil without affecting what happens in the combustion chamber.
You are only generating X amount of heat, the heat you are pulling out of the oil has to come from somewhere?
Oil coolers on other engines drop operating temps?
i got no problem making all the heat necessary to burn whatever fuel i want to burn
the engine has a closed and pressurized cooling system and runs over 207 degree's F, with the coolant in the
head being well over 220 degree's F, all the while with a radiator and fan to control the heat at this level.
and the fan runs with some consistency as well.
if there is 3000 btu's available in the oil, i suspect i could harvest 75% of it and not effect the fan cycling by much at all.
we have to remember the engine will be running at over 7kwatts electrical load continuously or a bit over 10kwatt mechanical
making heat is not an issue with a 195 working hard
bob g
Lloyd:
i am kicking around something along these lines
bob g
Bob, what's the agribed?
Ron
bob
Got to ask you about the particulate filter? Where would you find such an animal to match your changfa?
Could you please give a quick explaination of how it will be kept clean? Are you talking of the modern ones that burn them selves out when they get restrictive?
What kind of catalytic converter? what are they used for on diesels? are they for oxides of n or other?
So many questions so little time :( :( :( :(
Billswan
agribed = garden plot or green house plant bed
the particulate filter follows modern practice of a timed burnout based on restriction
the cat converter is optional at this time, mainly because of relative high cost
the idea was to improve the quality of heat more than trying to improve air quality
most of which i would find beneficial would take place with the particulate filter anyway.
bob g
the self cleaning exhaust exchanger continues to work as designed, there are other issues that i am considering
one of which is a provisional patent, and that is another story for another day.
the reason i am most interested in a particulate filter is not so much to clean anything but to recoup the lost btu's available in
the unburnt hydrocarbons that would otherwise pass on through the system. particulate matter being mostly carbon it would seem
prudent to regenerate and have at capturing those btu's as well.
going back to the heat exchanger
it is said everyone has one good idea in their life, and i am not saying this heat exchanger is mine, and i am not saying its not.
what i am saying is i don't know, and until i do know i will not be releasing any details as to its construction or theory of operation.
i figure my odds are only slightly better than those needed to win the lottery that this unit is something that is not only patentable
but of value to someone in industry. i know if i were to be in the diesel engine driven cogeneration manufacturing business i would
certainly be interested in an exchanger that did not require frequent cleaning, and i would be very interested in any auxilliary system
that improved upon the core unit.
maybe a pipe dream? who knows? i don't!
all i can say is in the last year of searching for a similar exchanger that operates on a similar theory of operation i haven't seen one yet.
bob g
Quote from: mobile_bob on January 28, 2010, 09:45:29 PM
agribed = garden plot or green house plant bed
the particulate filter follows modern practice of a timed burnout based on restriction
the cat converter is optional at this time, mainly because of relative high cost
the idea was to improve the quality of heat more than trying to improve air quality
most of which i would find beneficial would take place with the particulate filter anyway.
bob g
Ok bob I understand, I was also thinking kind of like you, but time time where to find the time to do the work :( :( :(
Billswan
Hi Bob,
I like the way you think, I am a pretty much off the shelf kinda guy, unless there is nothing on the shelf. The process of creating new from scratch is a long road, and efficiency demands the shortest rout to success.
Speaking of off the shelf: How To Order an Exhaust Scrubber; Removed at the request of the moderator
By the way Bob, my little perky/cat\volvo was going to get the leese triple nickel, but I'm now working with Niehoff on their 330, and a multistep reg, it's rated at 250 amp hot, with an efficiency factor well north of of the triple nickel.
For all you perky/cat owners..I added volvo to the name, because they marinize the same little shibrua, badged as the d-13 sail-drive, so that means that an off the shelf bolt on gear driven raw water pump, water cooled exhaust mani cooler, header tank, with tube bundle, and water injection exhaust elbo, are just down the street at your marine volvo dealer. I paid just south of $800. for all the above mentioned parts.
Lloyd
Bob,
I said before I like the way you think.
My project
(http://photos.imageevent.com/studio413/intheyard09/large/Copy%20_2_%20of%20IMGP0469.JPG)
http://imageevent.com/studio413/intheyard09;jsessionid=wtp3uvez92.panda_s (http://imageevent.com/studio413/intheyard09;jsessionid=wtp3uvez92.panda_s) More project photos here.
Started when we acquired a 1937 52 foot Grandy/Monk, that hadn't been under her own power in 20 years, she was completely gutted and stripped. The prior owner had decided to do a ground up restoration...he removed all the various bits and put them in dry storage on land...and didn't loose anything. So we started with the proverbial box job.
We did a major to both her 1962 vintage 6-354 perkins, borg warner gears, and walter v-drives. Every electrical, mechanical, and plumbing sys were replaced new.
I had to remairinize both perkins, I had SenDure build my tube bundles to spec, she is plumbed as I outlined above. I have a tank that has water coils for each engine, plus the future perky\cat/volvo, a 12 volt immersion coil(for dump loads), and a 120 volt immersion coil for dock side.
This is all plumbed through a radiant heating sys for the boat, that takes heat from my dickenson diesel fired galley stove as well. The system heats the domestic hot water(a separate tank), the boat, and will even pre-heat the perkins in cold weather. When dock side I can use the 120v coil to maintain low heat in the boat. We have also allowed to add a future diesel fired boiler...I'm not sure we will need it yet.
She cruises at 10-11 knots, and burns right at 3 gal per hour, My diesel stove burns more fuel that the engines do.
We been under way now since 2003, all elc/mec/plu sys are done, we are just finishing all her furniture and and interior rebuild..should be done for our annual trip north in August(750 mile round trip). We won the the best engine room award in 2004 at the Victoria Wooden Boat Festival, Bill Gardner(Gardener Diesel Engines) was chief judge, visiting from England...he said my marinization was better than the original perkns design.
Lloyd
WOW
Lloyd:
hats off to you buddy, that is a gorgeous boat!
bob g
Hey Bob,
Thanks,
That boat is our battery charger. Also our battery dis-charger, we started with what I call our 3-30 plan. 3 years restoration and 30 years annual maintenance. It's now something like 7-25, it's taken longer to restore but hopefully the quality of life will increase our longevity...not a science you know.
Lloyd
Mobile Bob
As someone who has spent years designing emissions systems, I would recommend that you switch the position of catalyst and DPF. The reason is that the catalyst will combust SOF (tar like hydrocarbons that otherwise plug up a DPF) as well as oxidize NO to NO2. The NO2 will in turn passively regenerate (burn off) the soot in the DPF without requiring active measures. In 2005 we put a SiC DPF on a cummins engined Dodge Ram and did more than 25k miles without the DPF needing to have any active regeneration. Just be sure that the catalyst you use is not one that is originally designed for a gasoline engine. The cells are often too small and can plug rapidly with diesel exhaust. Worst case scenario, you can buy an aftermarket catalyst in Europe since they have many popular small engine diesels.
The reason that this process couldn't be used in 2007 or later was the simultaneous requirement for reduced NOx. If the engine is made to produce less NOx (primarily by increased EGR in 2007) there is simply not enough left to have a meaningful effect on passively regenerating soot in the DPF. Since 2010, NOx can be reduced very efficiently by using Selective Catalytic Reduction, so most manufacturers (except International) have scaled back on EGR for better engine life and reduced maintenance. SCR systems have their own problems, but at least it is not the engine and the SCR catalyst has no platinum in it so nobody is going to cut it off in the parking lot in the middle of the night...
Welcome aboard Westcliffe01
Gad to see a diesel engine emissions designer on board, I am sure there will be lots of questions for you!
Sure hope you stop back often!
Good luck when you move to the Rockies!
Billswan
Westcliffe, welcome to our forum
its really cool getting someone with your background to come around and be part of our group.
the cat con i am going to use is supposed to be made for diesel engines, i was concerned with clogging it
with PM so that is why i had considered using a PM filter of sorts to capture and burn off the carbon before
admission to the cat/con.
my thinking is that my application where the engine is running at a specific rpm, specific load and temperatures
are very stable the issues of emissions should be easier to deal with than an application where the operation is
very dynamic, such as variable speed and load of a vehicle application or even the fixed speed but variable load
of a typical generator application.
when i get a bit further with my testing, i still have to completely dismantle the unit so that i can go back and complete
all welding, modes to the lubrication system of the engine, improvements to the ST head and a few other things.
then i will do the final assembly and start working on the control systems, and the emission control systems.
i am also very anxious to do some work with dual fuel mode, i am now quite interested in the use of gasoline in a pilot
injected dual fuel engine that is otherwise originally made to run diesel exclusively.
thanks for you input
bob g
Up to 30% of particulate is burnt in the oxidation catalyst before it ever gets to the DPF.
For stationary applications, the best thing that can be done to improve the performance of the emissions system is to heavily insulate it externally. Commercially made emissions components are regarded as "commodity" product, so there will be never ending negotiations between customer/supplier to get the last cent of cost out. Since the precious metal is under control of the OE customer and typically is by far the largest contributer to cost, everything else is wanted for free.... So the second most expensive item (the support mat that retains and insulated the catalyst) is made as thin as it can possibly be.
Adding a 1/2" of silica type insulation over the outside of the catalyst and exhaust and then wrapping it with soft annealed stainless foil from Mc Master Carr will reduce heat loss and help the catalyst work as effectively as it possibly can. In the case of a DPF this is even more important, since one wants the temperature of the filter as uniform as it can be.
Besides anything else, adding insulation reduces needless heat loss, which will make heat recovery systems more effective too. Heat exchangers, hoses, all need to be effectively insulated, particularly if the engine is in a cold environment.
mobile_bob:
If you go to: http://www.ejbowman.co.uk/products/EngineOilCoolers.htm
and download their webpage they have a yellow blurb in the middle of the page to download their .pdf file on exhaust gas heat exchangers. In there, somewhere, is a chart that shows what they expect that you could recover in heat from various function of a generic engine-generator (presumed, by me, to be diesel).
They think that you can recover 2 kW from the oil in a generator that is producing 16 kW, YMMV since their numbers are for a generic engine-generator, and I think that the 16 kW is a bit (??) bigger than yours and of who knows how much different in oil-path, block-cooling-of-lube-oil, etc., etc. But, the important part is, they think you can get 2 kW BACK, not what is introduced, but rather what you can recover. That's 12%, which ain't chicken feed since its almost for free!
Take a look when you get a chance!
i would have to go back and do some digging, most of my notes and all my books are now 1850 miles from me
so i likely won't know for a while, but from memory i think i figured on being able to get about 1kwatt heat recovered
from the oil system which would be about what is expected seeing how my unit is about half that alluded to in the article.
my cooling system radiator has the built in auto trans cooler that i will obviously not be using for that purpose, however
i figure to use it for recovery of waste heat from the lube oil system.
two things would be accomplished,
1. the lube oil heat would be lowered and recovered, and
2. the lube oil temp would be kept at about 180 degree's F at a minimum, due to the cold oil being heated by the radiator return
water heat which in my system is controlled to about 190 degree's F
yes a kwatt of heat harvested from the lube oil equates to about 3415 btu's, which is nice to add to the heat recovery of the system.
which in turn increases the overall system efficiency.
lastly i am seriously considering shielding the engine case with isulated panels, so that the radiant heat is contained and the cooling system
has a bit more to harvest from. the primary concern is noise abatement which is always important to chinese horizontal diesel owners, but
in the process more heat is recoverable, it too will only add to the overall efficiency of the system.
bob g
mobile_bob:
I am a fan of having a big tank of hot water available so that warm-up is a non-issue. When I was working at Ford, they tried to do a study to figure out when engine-surface (think: cylinder wall) and bearing-wear occurred. They found that the problem was so interconnected that it was almost imossible to address on a parametric level but they did conclude that 80% of the bearing wear in a spark-ignition engine occurs in the first 10 seconds after start. That sort of shocked me, until I looked at some numbers that they had for a couple of taxi fleets, where the engines practically never got shut off, and, lo and behold, the bearings in engines torn down after 150,000 miles looked and measured as nearly new. Cylinder walls, on the other hand, didn't seem to track - they looked as bad as ones from aunt tilly that spent their lives commuting 10 minutes back and forth to the store.
They later tried to do a dynomometer study, to try to weed out some of the extraneous variables, but they were just getting started when sales took a once in a decade dive and everything not directly connected to producing cars was cancelled!
I have thought that, based on that study, it would probably be a good idea to get a little gear type electric pump and pressurizize the oil gallery before start up, especially when you are talking about only doing it once a week, and there is lots of time for the oil to drain away.
About temp containment:
Every engine is, of course, different in its thermal characteristics, but for the Mercedes OM616 engine, in a vehicle they use a pretty small, mickey-mouse'ish air to oil cooler that doesn't look like a lot of capacity to me - maybe just basically something to protect, for a minute or two, when selecting maximum effort. The same engine, in a marine configuration, has a tube and shell heat exchanger that is about 3" diameter and 18" long, exchanging oil heat to cooling water, before the cooling water goes anywhere else, so it MUST be capable of extracting a substantial amount of heat from the oil. I'm sure part of that is the duty cycle, in that a marine engine usually operates at a higher BMEP than a road engine, but some of has to also be that the oil pan in an automobile with 50 MPH forced convection is shedding lots of oil carried heat and in the marine engine, sitting in the bilge, the heat rejection through convection has got to be an order of magnitude less than for a road engine. The Mercedes does have some sort of GEE-WHIZ gadget that samples the temperature of the cooled oil before it puts it back in the base and regulates it so they don't freeze anything.
About noise containment:
I just sort of figured that if you have a diesel (except maybe a lister/oid) running you better be wearing hearing protection, otherwise, in a little while there isn't going to be any hearing to protect!
Not sure, yet, how objectionable the noise from mine is going to be, in that it will be contained in an attached sort-of garage. I may be enquireing, later, for your design for noise containment! <grin> I would guess that it is a sure thing that I will not forget it and go to bed and leave it running! <smile>
Regardz,
Wayne Stayton