Atmospheric boilers

Ban

I have always been intrigued by the wet-based boilers with the gas gun. Unfortunately I have never seen any installed or functioning in our area. Everyone seems to go with standard atmospheric.



There are two things I don't like about standard atmospheric boilers: (1) The make-up air comes from the heated space and (2) there is lost heat to the floor. I once was visiting a friend in an old part of town and I saw he had attached a sheet metal sleeve around the perimeter of the boiler jacket and used duct work to bring fresh-air in from a basement window. How do you feel about this? Have you ever seen it done? Do you think it is safe or efficient?



Something else I was thinking about was the heat lost to the floor. What if when you poured your concrete pad you installed piping to help remove some of that lost heat? You could pipe it into your water heater(?) or add a circulating pump and heat one room with it(?)



Just thinking out loud... Thoughts? Comments?

nicholas bonham-carter

Waste heat

What about putting some stainless steel sheets under the burner area to reflect back the heat?

As far as piping in combustion air, I would be a little afraid of a freeze up when the boiler was off for a period of time. Maybe bring the combustion air closer to the flame would help.

Alternatively, we Midwesterners will have to buy and learn how to use an analyzer. Using a power burner has the advantage of dialing in the burn rate to match the system more exactly I would think.--NBC

Ban

Steel plate, Midwest, Damper

The steel plate Is an interesting idea! The way he had the duct work set up it had a one-way flap on the window so that when the burners came on the door opened similar to that of a dryer vent but the opposite way. I don't know if I would feel comfortable with his set up though. I think I would use a power damper in line with the flue so they both opened at the same time.



Agreed on the analyzer. Midwesterner's and atmospherics: I think it's due to a disconnect with oil for so long.

KC_Jones

I was just thinking about this!

I had the thought of putting a flat copper coil under the burners and picking up some of the waste heat as a DHW pre-heater of sorts.  I was thinking an experiment could be done with a cheap pump a coil of copper pipe and a 5 gallon bucket.  Would be interesting to see how much heat is indeed lost under the burners.  I doubt it's an overwhelming amount, but who knows?!  I think there are plenty of people on here that like to tinker maybe one of us will try it.  The metal plate under the burners could help, but it would need insulated from the concrete or that would suck up a lot of the heat itself.  There always seems to be some kind of off the wall discussion going on here.  Keeps the brain working!

ChrisJ

Cost

Something I've wondered about is the cost difference between a wet based boiler + power burner vs an atmospheric as well as the electric usage of the power burner.



Would you ever even make the money you spent on the install back.

What additional servicing if any does a power burner require over an atmospheric?

KC_Jones

Interesting thought

I don't think the price differential is so great that you couldn't make the money back in energy savings.  It probably takes years, but I would think you could get it back.  Besides that most average homeowners are probably paying someone to service their boiler yearly no matter what the type....well I hope they are lol.  My parents had their oil furnace (I know evil in this section) serviced every year and it lasted for 35 years.You do have a good thought though.  I often get into these types of discussions with people since I live in an old house (100+ years).  Everyone says replace windows do this do that etc.  It doesn't always pay in the end.  I insulate when I remodel a room that is a no brainer, but some of the other things I will never recoup my investment.  If people want to do it just for general energy savings for society more power to you, but don't sell it to me like I will make my money back because on some things I never will.  I do what makes the most sense for my investment.  Instead of new windows I rebuild my existing ones and use a modern weatherstrip kit and they come out quite nice and fairly tight.  For example all the work I did remodeling my kids bedroom their radiator is turned completely off and even on the coldest day this winter it never dropped below 65°.  Don't get me wrong when I build a new house...many years down the road I will spend the money and make it as energy efficient as I can because for that it makes sense.  The price difference on new construction is relatively small. Think I veered off course on my post?!  lol

BoBoBoB

You still have to heat the make up air

Regardless of where the air comes from, I suspect you still have about the same energy requirements.



If you're using outside air ducted directly to the boiler as the oxygen source, that air is cold, so you either expend more energy to heat it to the same flue temp or you get a lower flue temp and less heat transferred to the water/steam.



The main benefit, I think, would be that you control where that make up air enters the house. If you have a drafty house and you suck in make up air via the living space instead of directly into the boiler room, the living space will feel cold and drafty.



Since everyone here is concerned with the efficiency of making steam (as opposed to AFUE, which as I understand it doesn't subtract jacket losses), maybe someone could do the following measurement on a wet base and an atmospheric:



Isolate the boiler from the wet returns and drain the returns. This way no water returns to the boiler and the condensate has a place to collect. Run the boiler until the LWCO trips. Note how many gallons of water of water are lost from the boiler. Note how much gas was used. That should give you a pretty accurate measurement how efficiently the boiler throws steam into the pipes. You could get fancy and add water to the boilers to keep the water line at the "normal" level during the test if you want. You could also put a flow meter on the return if closing that valve gives you the heebie-jeebies. Since the amount of energy in steam is well defined, you can easily calculate how much heat went into the pipes.