Adding DPF to 350KW Generac

[LouNY]

As has been said adding a DPF will not improve the quality of any air the AC system is sucking in.
Just move the Generator or just run some suction duct for the AC to the other side of the building.
Someone wants to spend a bunch of tax dollars and pad someone elses wallet.
Any good tin knocker could fabricate some ductwork to draw the air from elsewhere or simply shut down the fresh air makeup air when the generator runs and use recirculated,
hopefully they are not using a system with 100% makeup air for AC.

 

[Chilliwack Murray]

May not even be a back room deal... Many government sites want to show they are ahead of the emission rules and going beyond because they are so progressive.

I think I mentioned that around here they spent almost as much on add on aftermarket after treatment systems on new generators as the generators themselves when it wasn’t required for their application. This on a site where they are extremely unlikely to run more than 14 hrs a year. On the operation and maintenance side they will add about 60% to the operating cost even if nothing fails. They keep about 750gal of DEF on site that has a shelf life of roughly a year and has to be disposed of and replaced.

After treatment is almost the new snake oil (only difference is the results can be tested and proven). It can be done right but should be properly integrated with the engine and will never have the reliability of the bare engine.

More and more small after treatment companies are popping up and putting the squeeze on public utilities and governments in particular since if they say no, they can go public and say “this or that public agency doesn’t care about your air”.

The same thing happened about 20 years ago with fuel polishing... A couple fuel polishing companies popped up and hit the government sites and large commercial buildings. If government sites said no, they wrote letters to the editor and contacted reporters who wrote newspaper articles, I remember one front page headline saying “80% of emergency generators may not start”. In 25 years I’ve seen two diesel gensets that wouldn’t start because of old fuel. Most actual fail to start conditions were and still are battery related for diesels. Nat gas and propane have more fuel related no start issues than battery.

I guess that’s another rant done.

To answer the actual question at hand, raise the exhaust above the roofline with sched 40 pipe is the proper solution and should have been done when it was installed. For 35’ there will need to be an expansion joint and hangers that allow movement but shouldn’t cost anywhere near $100k. I’d guess about $20k for a mechanical contractor, double that for a generator company to farm it out to the same mechanical contractor.

 

[Red Horse]

As has been said adding a DPF will not improve the quality of any air the AC system is sucking in.
Just move the Generator or just run some suction duct for the AC to the other side of the building.
Someone wants to spend a bunch of tax dollars and pad someone elses wallet.
Any good tin knocker could fabricate some ductwork to draw the air from elsewhere or simply shut down the fresh air makeup air when the generator runs and use recirculated,
hopefully they are not using a system with 100% makeup air for AC.

Guys-again thx for all the comments. Check these photos out. I found this installation in a neigboring town-looks like its on a 250 KW unit. Does this thinwall stainless look like it would cost 100G? Check the anchors on the brackets on brick work!

 

[Chilliwack Murray]

That’s not thinwall stainless, it’s most likely sched 40 with insulation. There stainless you see is a shell to protect the insulation.

 

[mrmikey]

That sure looks like a Selkirk chimney to me, if not it's a twin to it.
Looks like a fresh air intake beside it too LOL.........Mike

 

[Red Horse]

That’s not thinwall stainless, it’s most likely sched 40 with insulation. There stainless you see is a shell to protect the insulation.

Well you might be right...but if it is, I would not want to be underneath it some day when those 4 lags on the 3 brackets pull out of the brickwork. 6" 40 is like 19lbs a foot? I was thinking it was double wall stainless. Again, perhaps you are correct but I look at the way that thing is attached to the building and it says "lightweight" to me.

 

[Red Horse]

That sure looks like a Selkirk chimney to me, if not it's a twin to it.
Looks like a fresh air intake beside it too LOL.........MikeView attachment 665138

Mikey-Selkirk is a brand?

 

[Chilliwack Murray]

It shouldn’t be thinwall tube on a generator, it’s not designed for those temperatures.

Download the T-030 manual from
Cummins for everything there is to know about installing a generator.

 

[Red Horse]

It shouldn’t be thinwall tube on a generator, it’s not designed for those temperatures.

Download the T-030 manual from
Cummins for everything there is to know about installing a generator.

Ok CM-thx. I looked up Selkirk per MrMikey and I do believe that is what it is. The brackets in the photos I took match and they have a product line intended for generator installation. I'll check out the Cummins manual as you mentioned. This thing is powered b a Deere "big block"-like 13 or 14L.

 

[mrmikey]

Mikey-Selkirk is a brand?

Yup Canada ,. I do believe there are other brands but it is the most common around here. It's what I have on my woodstove, no complaints with it...other than the cost LOL. My next door neighbors had a chimney fire a couple years ago, turned the top foot or so a nice shade of purple, must have burned for 20-30 minutes until it was noticed and the FD showed up, no damage at all after it was inspected.

It shouldn’t be thinwall tube on a generator, it’s not designed for those temperatures.

Don't think it would get that hot would it? I'd think the problem to overcome would be lack of heat, especially on a long run, hense the insulated exhaust. Notice what appears to be a drain on the bottom of the vertical stack, bet that's for condensation...........Mike