Yanmar 2tnv Micro CHP

[mr.fixit]

Here is the latest version on my cogenerator.It's a surplus center Yanmar 2tnv belt coupled to a HF 7200 watt gen head.
I ended up remounting the engine and gen head on a more stable platform.Actually it's a old electric ride on pallet jack that i originally bought just for the battery.So it isn't the prettiest but very stable.
I also mounted both the engine and gen head solidly and used a belt tensioner.The engine does sit on 4- threaded stud transmission mounts to isolate some vibration.
One mistake I made was I put the tensioner on the tension side of the belts instead of the slack side,but it seems to work fine as is.

I used a stainless steel swimming pool HX for the exhaust HX.Same one SPS used on their system.It really works well. It and the engine cooling system are plumbed in parallel thru a flat plate HX with the other side of the HX plumbed into the boiler storage tank that heats the house.

I think the best improvement I've made is isolating the exhaust HX with flexible couplings between it ,the engine and rest of the exhaust system.

The HF gen head has worked ok.When I received it the plastic on the end cap and the voltage regulation capacitor was damaged but they sent me new ones.I finally figured out that the capacitor has to be in the exact mounting place as it is located by the air intake vents to keep it cool I suppose.

Although I don't have any numbers yet,I believe I am getting considerable btu's from the system when running 4500-5000 watts into the inverter-charger.

It's been a fun project but always more fine tuning to do yet. http://youtu.be/yhG_h8LF1q4
Can't get the video loaded so I will add some pictures

[DRJensen]

Are you running the engine at 3600 rpm? I have mine set to 2800 +/- and a 7.5 kw ST head for 1800 rpm. I can only produce about 4500 watts at that engine speed. I know it makes more horse power at 3600 rpm but wanted longevity from the engine. Could you show a picture of your plate heat exchanger as I want to heat my domestic hot water off the coolant side of the engine. I live in florida so the heating load here isn't much so there is really no need for capturing all the btu's the engine puts out. I built mine as a back up for outages but since found a steady supply of used ATF. I filter it and mix it 90/10 with diesel fuel and supplement my grid power in the evenings when at home. I run it for 4 to 5 hours a night and 20 gallons of the mixed fuel last more than a month. I posted a write up and pictures in the memebers project section. Here is the link:

http://www.microcogen.info/index.php?topic=3085.0

[mr.fixit]

I run it at 2650 rpm. It handles 4500-5000watts with ease.
Tried to post a picture of the plumbing but it won't allow a jpeg?Worked last post so don't know whats up.
Did a 6 hour run today and here are results;
Hours run-6hrs
KWH's produced-27kwh's (measured with utility type meter)
Water storage tank mixed temp start  122F  ending mixed temp 162F rise of40F  tank is 500gallons so 500x8.3lbs gallon =4150lbs X 40=166,000btus/6hrs=27,666btu/hr
I am keeping track of total fuel use over a longer period of time so I have no numbers on that right now.

The flateplate HX I am using is a 40 plate,but I believe a 30 plate would work ok but doesn't hurt to oversize it.

[DRJensen]

Thanks for the reply. I see it took six hours to raise the 500 gallon tank 40 degress to 162 with a 40 plate heat exchanger. Right now I am only trying to heat a 50 gallon domestic tank. I run mine about 4 hours a day in the evening so a 40 plate heat exchanger might be to larger. I am afraid I might have to add a bypass around the exchanger because my tank will rise to max temp longer before my 4 hour run is over. If I use you formula, I would need 6225 btu/hr to raise 50 gallons from 100 degrees to 160. I need to look at a data sheet for the heat exchagers to find the right size. Thanks again, Dave

[mr.fixit]

Update on the Yanmar.

So I have some not so scientific,but long term operation fuel consumption and BTU output numbers for review.
Almost a year ago I ran it out of fuel (not on purpose) so I thought it would be a good time to keep track of the amount of fuel I use. I put exactly 5 gallons in my transport containers every time I filled them. Now I know that this is not as accurate as weighing consumption,but I buy it by the gallon so this is close enough for me to get a good idea of my operating cost.

So on the 21st- 5 gallon fill I ran it out of fuel again, on purpose this time. It used 105gallons and ran 198 hours, which comes to .53gal/hr.

Now naturally my kwh meter died,and it took me awhile to replace it.But since replacing it I average 4.8kwh per hr. This also is really close to what the Combox(monitoring system for the solar system)reports. As of lately I have been loading it down to more like 5000-5500 watts.

On the heat output,I did a btu test a couple times,when the storage tank was down around 100F. The generator cooling system and exhaust HX are tied into the 500gal. water storage tank via a flatplate HX.  EGT at head was 730F and temperature after exhaust HX was 335F ,with 5500watt load.
Both times the total  btu/hr came to 29000-30000 btu/hour.

I did end up removing the spring loaded belt tensioner ,and just tighten the belts with sliding the gen head in slots. I found that the XW6048 inverter qualifies the generator input better this way,I suppose less belt deflection and more stable frequency.

Any ways it keeps purring along nicely,making me heat and electricity. The little yanmar has 625 hours on it now,still uses no oil to speak of between changes.

Addition; Should note that 90% of the fuel I used was 70-30 mix winter blend. Slightly less btu/gal.

[mr.fixit]

Recently replaced the generator head with a 160 amp leese-neville alternator to directly charge the 48 volt battery bank instead of going thru the inverters charger.
Its a 7700 series alternator with external field brush connections so wiring up an external regulator was a snap. The regulator is a DC power systems regulator similar to balmar but with less adjustments available.
Running it @6400rpm puts out 85-95 amps @50 volts.
Eliminates all issues of the inverter syncing with the generator and then dropping it when hit with a big surge load.
Have run it about 25-30 hours,guess we'll see how long it goes.

[veggie]

Nice project. Well done !

Good to see that the system is giving you reliable power and heat.
I'm surprised you can get 5kw from that engine at 2650 rpm. Is she blowing a bit of black smoke at that point?

When you state that the fuel is a 70/30 winter blend, are you referring to 70-Diesel/30-kero ?
or maybe 70% WVO and 30% RUG ?

Veggie

[mr.fixit]

Thanks,yes in the winter here they sell the winter blend #1 & #2 red off road diesel.
That engine doesn't hardly smoke at all.
I have over 1000hrs on it now and it is usually down half a quart of oil when I change the oil every 200 hrs.

[Tom Reed]

Will the voltage go to 60 for equalizing batteries with this alternator?

[mr.fixit]

Think it would with no problem.
This regulator has pre set charging profiles,but you can choose FLA ,AGM .
The absorb setting is 14.7V so 58.8V on 48 volt system and it does that easily.
The balmar regulator with all of its adjustability would really be the way to go.