We have just finished the installation of an oil fired boiler running on B100 for a small greenhouse and farm store. Each section has it's own independant loop back to the boiler head and are controlled by thermostat on solenoid switches.
What can we expect in teh way of fuel consumption ? Ball park will do,I can figure it out from other application's data.
Ball park should be close to the size of the nozzle in the burner. Since you are running bio, which is more viscous than hho, consumption will be a little lower than hho everything else being equal. You can adjust consumption a little by way of the pressure adjustment screw on the pump, but that is not the real purpose of that screw.
Can you give us some info on type of boiler, oil tank, etc.
I'll get the specifics and get back to you. I know the burner is a Beckett and the people who set it up used a 100Lt poly tank to feed it with. It is not doing hard duty, it is only being used for heat in a small greenhouse and store, but seems to have a thirst that I was not prepared for completely. I've put 1,000 Lt's aside for it, but at the rate it is now being consumed (.85 nozzle at 150PSI with a polished CAD refector) it won't last the winter.
Thanks for the comeback guys; always best to get information from those who've gone on before.
I would think that the only thing that matters is the amount of BTU,s per given equal volume of fuel.There are approx. 140,000 btu,s per gallon for No. 2 fuel versus 130,000 BTU,s per gallon of vegetable oil based biodiesel.
So as you can see you will burn approx. 9% more bio than dino No. 2 too make the same amount of BTU,s
Yup.. that's pretty much the story in a doggy bag...
How many BTU's is the boiler rated for?
Never underestimate the power of:
1. Insulation: Many people make the big mistake of not insulating pipes correctly. Especially underground or outdoor piping..
2. Lowering the thermostat a few degrees: Just 3 degree's can save 10% on energy costs.
Are you feeding it washed and dried fuel or just raw biodiesel ?
One more comment,
You mentioned nozzle size... I'm assuming that has an effect on the output power of the heater itself? Referencing the same unit with the same heat exchanger, as you lower the output power of the unit, the effeciency of the unit should increase.
You may also consider putting an air-to-air heat exchanger on the exhaust stack to scavange the wasted energy.
Hope that helps.
Oil consumption is going to be based on heat demand. An uninsulated greenhouse would probably have a pretty high heat demand. If the place has a store front with alot of customers coming and going through the front door, there would be alot of heat loss there too.
Really the only thing you could compare to would be other uninsulated structures like the greenhouse.
Thanks for the replies, mucho food for thought. I believe there was an error made in letting the heat go uncontrolled for a weekend (from what I am told) and it essentially warmed up the neighbourhood,so no wonder the fuel gauge dropped like lead in air eh?
If the farmer runs out of B100 it'll be dino time or the avocados learn to live with winter. Seriously though I think he just needs to be a little more careful with fuel use. I'm still going to get all the details the minute I can in case there is something one of you with experience at this stuff sees what will go right over my head in plain sight.
OK, I think I got it figured out; the burner is a Beckett AFG, but when it was tweaked the nozzle installed was a 1.5
It has now been swapped for a 1.0 and is on the way down to a .85. The CAD was moved up closer to the flame and the tube polished with an aluminium paint.
It cycles perfectly on B100, but due to the HUGE nozzle was doing a burn overkill. The saga continues.Will post more when I have more.
The huge output is probably causing a major drop in efficiency of the heat exchanger.
I would think its better and more energy efficient to run the burner longer and lower than short and hot.
If you are thinking of .85, I'd start thinking .5 or so.. (maybe but I'm not sure exactly how that goes)
Here is a table from the Beckett AFG manual showing the actual flow rates for nozzles. The rated flow rates are based upon 100psi.
At higher pressures, the flow rates are higher.
Hope this helps.
I don't have it in front of me and I have to run, so I may be missing something...
But I think I remember that (below .85?) nozzles require a (low fire rate head/baffle/?).
I read that in the manual some time ago, but old age is setting in and the terms might be off...
I used the .85 on mine because it was in the original kit as an option, along with a different retention head.
I filed it under, "Hmmm... I'll have to remember to look that up if I need to drop to .75"
Legal- if you were running dino at 1.5gph and 150psi, you were running at 1.84 *gallons* per hour!
You were probably inefficient and short cycling your burner...just like I was some time ago
Until I started digging into this stuff, I never thought about the flow differences at the higher Beckett pressures (default preset setting was 140psi on my AFG).
Let us know how you make out with this. I'll be testing CAD readings this weekend, per another request with B100.
Thanks for your help guys. By that handy chart JCB posted I can already see where a drop in nozzle sze will have a DRAMATIC effect on consumption. Serves 'em right to let a guy from a major oil company come and do the set up; he put in a nozzle that would suck up the juice like it was free or something.
I'll have to copy that and pass it it on.
Bringing the CAD in closer to the flame (it only moves a little) and polishing the grommet with silver paint has it cycling perfectly.
Now for a nozzle swap ...
Glad to hear you're getting that worked out.
A couple more tips just to help (maybe)
*Make sure your heat exchanger is clean! If soot builds up on it, it can act as an insulation and lower the efficiency.
*If you have duct work that moves the heat around, make sure it flows freely! Undersized blowers, closed duct vents, clogged filters, etc etc can all increase the amount of fuel you burn.
hope that helps but you probably already knew that stuff.
Thanks Murph; Don't assume I know much about boilers, I don't. Most of what I know comes from what people like you post. I am a fairly quick study though. And even if I do know it there might be someone coming up later that doesn't so any input is appreciated sooner or later.
The boiler is brand spankin' new as is all of it's components. I originally was under the impression that the nozzle swap was down from a 1.0 to a .85, but it went the other way to a 1.5 (like putting a beer IV into a vein, it just keeps right on sucking).
The greenhouse has been "bunkered" for heat retension but open enough for evacuation and air circulation and we are dumping the heated air from teh greenhouse into the farm store instead of outside getting full bang for the buck if you will; this has helped a lot. Nothing like heating the out of doors when it is cold .
I still have a little while before I will be shutting down for the winter so I'll have plenty of extra fuel for me and "the beast"; hopefully enough to last us through until the sun does it's thing again.
Thanks again for all the replies.
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