Welcome to the Windshield Chronicles, a mental sequence of operation.
This episode brought to you by Rachel Kaiser and as part of her class,
taking the chemistry of combustion into your classroom so you can have a complete
understanding of the chemistry and the sequence of operation of combustion.
Hello, everyone. Thank you for joining.
Did you know the ESCO HVAC podcast?
So we are still here at the 2024 National HVACR Education Conference,
and I'm hanging out with Rachel Kaiser. How are you today?
I'm good, Clifton. This is an exciting event, and I'm really excited to join you this afternoon.
It has been crazy. It's starting to wind down. It's a little quieter out here.
I think everyone's going, all right, my brain's in meltdown mode.
Yeah, and it's always the figure out what session or how they can bounce between them.
And I mean, the next round of sessions just kicked off.
Yeah, and I think we had like a hundred and some sessions.
So there's so many different topics.
And your topic that you covered in your class, which I highly encourage everyone to sit in class
and go through the full length version of it.
Yours was very interesting. I was curious myself.
Yeah, it was an exciting opportunity to share some more information on how you take
the chemistry of combustion and take that into the classroom.
And so it was a nice combo of offering attendees insights and some deeper dives into the whys
and hows of the chemistry that was happening that you encounter in the field for combustion
and how to take that and take the step back and take that into the classroom in a way that distills
that chemistry into a relatable, digestible output for any kind of learning group and
ways to introduce them to the complex interactions at the molecular level that aren't relevant.
Thinking about them as molecules in that molecular level that I as a classically trained chemist
was taught to do. But why is that relevant to kind of troubleshooting and safety paradigms
and things that a technician and students learning to become that technician are going to care about?
Okay, now we're getting somewhere. As I know myself and all educators that are joining us,
I learn to fix things by understanding how they work. And it kind of goes back into education in
the same way. I can't deliver something if I don't truly understand it. So is there a short form
version that we can dive into? Oh yeah, I think so. I mean, yeah, I mean, essentially what I
am trying to come across is that the course is giving you the base scientific chemistry that's
happening before you go and take that next step of learning on how to leverage analyzers and take
them into the field. So it is exploring what so many textbooks and this is whether you're in a
chemistry class or utilizing HVAC training manuals. They start with a very basic and they always
highlight balanced reaction to explain what's happening with combustion. And I dive at and
explore if that basic reaction is actually relevant or helpful in the long run, because it gives a
simplify which makes it easier to talk about explanation of what you want to be happening
with combustion, but it is a non-achievable reaction. It is a situation in which it is saying,
so the three basic pieces for a reaction that you need for combustion is you need a fuel,
you need oxygen, and you need a heat source to move your chemical reaction forward. So what you
usually see is a CH4 molecule or methane. You add that to two O2 molecules. You have your heat
source, whatever that ignition source is. In my talk, I like to represent it initially as a match
because it's something both real world, no matter what level a learner's at, they see that and then
it's giving instructors, you build up on where that ignition source changes for those real world
applications. And each one of those, it's breaking down and taking that those three elements always
need to be there, but that reaction of where I started with that one methane, two oxygen, and an
ignition source then balances out and you only get CO2, water, and heat out. Sounds pretty simple.
And if that's what we actually got every time, we just have CO2 and water. And why would we ever see
these lawsuits around CO poisoning from combustion equipment? Absolutely. Why would we have degradation
of our venting and heat exchangers and things from acids that we encounter? Why would those types of
things, if that was the reaction and the reality of what's happening from that chemical standpoint,
then we wouldn't see those real world scenarios and the real world is never as clean or as easy to
navigate. Things aren't where we wanted them to be. And that basic equation is assuming that
everything is exactly where we want it to be for that chemical reaction. So a key piece of that that
dive into is, for instance, those two O2 that we expect in that balanced reaction, they come from
air. Yeah, exactly. We don't have an O2 cylinder sitting by everyone. We're not being straight oxygen, are we?
We are not. And so it was diving at, for instance, like real world, do we have any situation that
is pure oxygen? And in reality, there are some examples in which we have pure oxygen atmosphere.
NASA makes it during the Apollo, Mercury and Gemini missions, those particular space modules
all had pure oxygen atmospheres. Well, Apollo 1 kind of used that pure oxygen atmosphere and had a
significant fire that cost the lives of those three astronauts. So we see that that pure oxygen
atmosphere definitely supports combustion. However, the cost and the control to put that pure
oxygen atmosphere in those situations and into that environment out of the gate is costly and
takes a lot of control that we are not going to have. Yeah, not going to be available for the
average homeowner. It is not. And I mean, we think we have air sealing issues right now in house
envelopes or building envelopes of any type. If you were trying to ramp that all the way up to
it being able to withstand and hold a pure oxygen atmosphere, that would be a whole new building
hurdle that would be not easy to cross. We're probably not going to encounter that. Yeah. So
I mean, it's achievable, but not realistic. So like you dive at those and look at that. So then
it's, we are going to have that combustion taking place in air. Is air all O2? Well, obviously not.
That's why we're talking about that. So it's exploring what the typical compositions of air
are, because what we first saw is that simple reaction. It always goes back to that simple
reaction that people get taught and exploring if that is truly what we would ever see happening.
Because never does it does combustion mean that we aren't getting CO2 in water, right? But what
else are we getting and why? Yeah. What other inputs did we feed into our reaction to be able
to see what our outputs are? Yeah. Correct. So now you got the brain. It's awfully late in the day
to be thinking this hard, but I love this conversation. So like if you look and just
taking basic numbers, again, continuing on that, just looking at the oxygen component needed for
combustion, roughing the percentages you're looking at so that it becomes an easy demonstration to
bring into your classroom. You can take, say, an example I give is balloons. So if you do one red
balloon as one of the oxygen molecules you need, and you do another balloon as another of the O2
molecules you need, then you can proceed to do the same for the nitrogens to represent that. So you
would have two red oxygen balloons that give your 20% and then you fill it out with the other 80%
nitrogen, which is an easy clean. That's not completely representative of everything. You have
an air, but it starts to give a super visualization for your students as well as for yourself.
I love that. On what that means because that fuel that you need has to find that oxygen or you won't
be having combustion. So if there's all those nitrogens around and even again stepping back to
that idea of keeping things simple, even if the nitrogens didn't react, just the fuel trying to
find those oxygen molecules or red balloons amongst a sea of blue, nitrogen balloons, you're
instantly in a space that you start to see where mixing and having the air available to
for the fuel source to mix with, to react with, however you want to term that, that best correlates
with the kind of program you already have in place. That's the, gives you the foundation to start to
visualize why that can be problematic. All I can see is color balloons right now. I'm looking out
into nothing and I'm seeing my colored balloons going, why isn't this hanging in every classroom
in the country? It's so interesting to think of it from that perspective and the amount of work that
has to happen in that reaction to be able to isolate those oxygen balloons out of there.
Correct. So I'm in, and I gave like as another tip was whether it was balloons or another super easy
and low cost way to do that is just get card stock from any of the box stores in the Kellers and the
those individual card stocks can represent the molecules as well. And you can do the same where
you start to set up that say the front of your classroom is your burner and that would be where
your fuel gets introduced. So you build card stock, use paper clips and just the four by six piece of
card stock in the different colors that represent the fuel or the oxygen, the nitrogen, any of the
components that you would typically encounter even again, keeping it more simplified and you can show
those issues with mixing because your fuel's coming in from one source. It's not coming from everywhere.
No. But your air and oxygen is coming from another part and so they are segregated.
Yes. That you can exemplify by using your learners as part of the environment to demonstrate where
a burn, a burner and that ignition and everything comes from and lay that out
at that interaction of what's happening for the combustion. I'm blown away. That makes so much sense
when you present it like that. Okay. So I mean, in my outline, it was those taking those each time of
breaking down. So where I just laid out for air and that complexity it brings, you add in things,
it's bringing, I've talked about oxygen and nitrogen, but there's water in that.
There's argon, there's, you know, you can just keep adding. Okay. So that's what the
makeup of just the air is. However, that's looking at it from a stratosphere of the globe kind of makeup.
Absolutely. Great. But we as humans are adding all kinds of chemicals into the air.
And detergents. Yes. So anything, whether it's the people, the furniture, the cleaning supplies,
you've painted anything, exhaust from other activities, be it cooking, vehicles, all sorts of
activities that are in our world, which are next to where we have our combustion taking place with
these appliances, those all add additional chemicals into our air factor of our combustion reaction.
Wow. You know, I've always promoted the use of dual pipe installations for high efficiency gas
furnaces. I've always been a big proponent of that and been against using single pipe systems and
using your interior air for your combustion and for the efficiency of it. But typically I was
looking at that from the perspective of utilizing that oxygen rich, you know, outside air. Now that
I relook at it, it's like it even more importantly, it's to remove the combustion air from the
contaminations of the indoor environment. And that's a fascinating point Clifton, because
so we do that even in those direct vents situations where you have those two pipes and you're doing
the best that you can thinking, hey, I'm going out and I'm getting fresh air for this combustion
process. It's controlled in a much better way from not randomly pulling air from whatever room that
that appliance is in. However, and I demonstrate this in my talk was going through and going, you
know, that fresh air, that's not as fresh. It still doesn't meet what we just described of even only
having the oxygen nitrogen argon type of piece because you have to look at what that environment
is. As soon as you pipe outside, we have all these things happening now. Wildfires. Yeah.
Look at the chemicals and the particulates and all of that. Even if you have gone to the step of you
have exactly what you have supported of that pulling in your combustion air from outside in
its own pipe situation and setup, you're outside, you need to do some analysis and look to say,
what else am I going to pull in even from there? So there's no such thing as clean combustion air.
That's what there is no clean combustion air. It's more what else could be pulling in and it could
be very environmental yet may be fine for a while. And you have scenarios. I actually laid out one of
those hypotheticals sharing with the class is if you have that two pipe system and it's outside and
that house is along a busy road right by an interstate, you are automatically in an environment
that has a lot more exhaust particles in it. And that's going to instantly affect that fresh air
and add to the chemistry that's going to be happening within that combustion chamber.
I want to go to this class now. I love this. I love the idea of that. I think that would make
a very, very good show sometime to do some visual analysis of that to be able to bring that to life
because I completely sitting right here, I'm imagining all of this in the process and it helps
us truly understand that science, the chemistry behind that reaction. What are we actually doing
here? What are the byproducts of a reaction? Correct. And that's the piece because
just having, say a car come by that will go back to that direct vent and you have that pipe outside.
If just one car pulls up one day and has exhaust when that appliance kicks on and is pulling that
obviously not quite fresh, what we would like to think of, but pulls that air in with that car
exhaust near it, that will make the additional byproducts and create additional chemistry
experimentation within that combustion chamber for that day. But is that going to be what you're
going to see within the system as degradation or outputs on one day? The answer on that is that may
not be a critical factor. However, if it is a house with that vent where it's every day by a big
interstate where you have that constantly pulling through, then you're increasing your probability
of that additional chemistry happening at a level that then has an impact. Because from a theoretical
sense, we can draw on a piece of paper or on a computer screen all of the things that we're
doing, all kinds of possible chemistry that could be happening with the number of contaminants that
you can have in air, even alone and continuing to go with the idea you have a simple methane fuel.
But is it enough and at a high enough concentration to be impactful? And we know that from all the
experience of all the different instructors and technicians in the field that they encounter
things that there's definitely additional chemistry happening. Oh, yeah, they wouldn't
be out there trying to problem solve a number of the scenarios in which they walk in. And it's
about giving them some of that why so that they can not only be better problem solvers when they
encounter them in the field, but be safer for themselves and the occupants of the structure.
I love it. That is a fantastic topic for us to cover. I appreciate you joining us so much.
And I look forward to a in-depth version of this down the road. I see it as a possible webcast
because my brain just going that clean air is not as clean as I thought it was.
Yeah, that was only one part of the combustion we explored Clifton.
Oh my gosh. All right. I'm interested. Well, Rachel Kaiser, thank you so much for enlightening
us on combustion and helping us move that message forward and helping educators and
contractors and technicians and students all understand things by getting a deeper vision
of what all these different balloons look like floating around in the sky. Thank you so much,
Clifton.