Kubota D905 direct drive Co-gen build.

[RJ]

Well work has started as I have dismantled my former generator setup which was a Kubota D905 direct coupled to a ST-12 head. When I built that unit it was on a trailer so I could move it around when building my house.



I have now direct coupled it to the same 7.8kw head that Henry had on his D1005. I just finished building the frame and should have it all painted and mounted up by this weekend. This unit will be semi-stationary. I can pick it up with the lift points with my tractor, so if I need to load it on a trailer for remote work it can be done, while in the shed it will be connected to my heating system.

Goals of the build:

• Prime power of about 6kw for the home
  
• Provide at least supplemental heat for the home during extended ice snow storms.
  
• utilize a marine engine heat exchanger to pull 20-40kbtu from the engine depending on load.
• eventually automate the system in the future.

I still have to secure a heat exchanger for both the HVAC duct work, and the engine itself. Looking for idea's. Also need to decide on a circ pump, will this closed loop need an expansion bladder? Plan is to use RV glycol in the loop as parts of it will be exposed to zub zero temps.

This is the basic gist of the setup in a diagram.

[Lloyd]

Look for a new/used Mani Cooler/tube bundle. That will also capture part of the exhaust heat, it will provide for quicker engine warm up.

Then set up a temp controlled bypass to an external radiator, that way you won't lose any heat to the rad unless it's needed.

Lloyd

http://www.orcamarine.com/news.html

20 November 2006
ORCA introduces Manifold Cooling System for Kubota D905, D1005 and D1105 Diesel Engines
Orca Marine Cooling Systems announced today that it has introduced a newly designed closed freshwater cooling system for the Kubota D905, D1005 and D1105 diesel engines.  An aluminum manifold is the heart of the system, with a removable "core" with copper shell and copper-nickel tubes.  Other parts include brass end caps and a new thermostat housing with an additional NPTF fitting for a temperature sensor.

The system is designed to accommodate propulsion, generator and auxiliary uses A 316 stainless steel exhaust elbow with integral injection quill is available for wet exhaust systems. A modified manifold without the engine cooling components is also available for keel cooled, dry exhaust systems to provide for exhaust manifold cooling.

[RJ]

Alright, well I finally got some time into putting this unit together. I made a call to Marathon to clarify a few things with this generator head. The unit has a total of 8 leads coming out of the generator. I could figure out 6 of them. T1-T4 are used for power and then there is a Field plus and field negative. I also had a E1 and an E4 that had me miffed. After speaking with marathon all was figured out. The generator is designed to run with a couple options for AVR's. Some AVR's such as the SE350 require ~240v for power. The unit that was shipped with the generator I purchased ONLY uses 120v for power, but it will sense 240v. Marathon said I could cap the leads and wrap them up. Since I wanted the option of running the engine but not produce power I installed an On/Off switch to turn the regulator on and off,  instead of capping E1 and E4 I opted to use it to power a 250v neon indicator light to tell me when the generator is on.

The frame is 4" channel stock and the entire unit is mounted on 4 isolation mounts. I can pick the unit up with my tractor back hoe no problem with the lift hooks.

You will notice I opted to install a power out put panel instead of hard wiring the unit into my xfer switch. This was done so I could still use it as a portable unit as well. I purchased the generic panel at Surplus Center for 10 bucks. It includes a 30 AMP twist lock and two 20 amp 120v sockets. It came equipped with 20 amp breakers, since I was looking for the full 30 amps I replaced them with new 30 amp breakers, I also upgraded the wiring from 12 AWG to 10 AWG inside just to be safe.

I also decided to include the engine control and hour meter in the box instead of the stand alone box that I used to have.

Things to do,

-An actual test. This should come the end of next week. I'm headed to Maine for a little R&R.
-Heat exchanger hookup and mount. I have my eye on a few.
-Larger 55 gal fuel tank.
-Find some 1.25" exhaust for additional exhaust venting.

So here are some pictures of how the units sits now, taken this evening

[RJ]

Couple more

[RJ]

Last but not least...

[Henry W]

RJ,

It looks good! Very neat wiring. I am looking to read more about your setup.

Henry

[RJ]

Okay, after some R&R in Maine, then some stone wall building back at home on Saturday I was able to take a swing at this on Sunday. I pulled the unit out and hooked her up to a temporary fuel tank primed the system and gave it a whirl. After a few cranks the Kubota started right up. I then set the frequency and voltage, both are a bit high right now as I set it under no load. I have yet to hook it up to the house and try it with a load, once I do that I will set the fine adjustments. The regulator on off switch works like a champ. For some reason I tried to talk a couple times in this video and you can't hear a thing I say, so just ignore it! I did end up running it in the shed, I got the thumbs up from my wife regarding noise levels in the house, you really have to listen for it.  

Things to do still:
- plumb exhaust in the shed
- work on co-gen application details and parts.
- install switch to flip the xfer switch until it gets automated.
- Load test

You can see my 3 year old daughter wave to everyone at the end of the video

[Mo]

Greetings, hoping for developments.  Thanks Mo.