FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 


any clever Ideas out there for preheating intake air?
Goto page 1, 2  Next
 
Post new topic   Reply to topic    The Smoke Ring Forum Index -> Cookers
View previous topic :: View next topic  
Author Message
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Thu Jan 27 11 11:03 am    Post subject: any clever Ideas out there for preheating intake air? Reply with quote

has anyone done this with success ,or is this just flat out unnecessary?
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
SoEzzy
Site Admin


Joined: 13 Oct 2006
Posts: 13183
Location: SLC, UT

PostPosted: Thu Jan 27 11 12:01 pm    Post subject: Reply with quote

If I was going to heat or cool intake air I would cool it to get more O2 into the fire, same way the intercooler works with a turbo!
_________________
Here's a change Robert.

I still work here!
Back to top
View user's profile Send private message Send e-mail
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Thu Jan 27 11 12:24 pm    Post subject: Reply with quote

Wow! SoEzzy its an honor sir!, I understand that cool air is denser that hot air but does it have less o2 just based on that hot air is slightly more expanded?

also do you think there is a real differences in fuel consumption, Thanks
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
Smokin Mike
BBQ Super Pro


Joined: 02 Dec 2008
Posts: 3142
Location: Winston-Salem, NC

PostPosted: Thu Jan 27 11 8:56 pm    Post subject: Reply with quote

I'm not exactly sure what your end goal is but I would make some sort of heat exchanger (a reclaimer) using the radiated heat from the firebox to pre-warm the air. If hotter temperature is what you're after then forced air would crank things up, just like a forge... but there goes your fuel consumption.
Back to top
View user's profile Send private message Send e-mail Visit poster's website
jess
BBQ Super Pro


Joined: 26 Sep 2007
Posts: 1831
Location: Fl.

PostPosted: Thu Jan 27 11 9:47 pm    Post subject: Reply with quote

SoEzzy wrote:
If I was going to heat or cool intake air I would cool it to get more O2 into the fire, same way the intercooler works with a turbo!
x2...
Back to top
View user's profile Send private message
day_trippr
BBQ Super Pro


Joined: 08 May 2009
Posts: 3206
Location: Stow, MA

PostPosted: Fri Jan 28 11 12:16 am    Post subject: Reply with quote

jigsnpigs wrote:
[...]I understand that cool air is denser that hot air but does it have less o2 just based on that hot air is slightly more expanded?


Yes.

Quote:
also do you think there is a real differences in fuel consumption, Thanks


That would depend on whether you actually changed anything with whatever it is you're thinking of doing - which, btw, you've yet to make clear.

So, what was your goal? Are you trying to achieve higher cooking temperatures, or are you trying to maximize fuel efficiency? I'm not sure you could do much to either, fwiw, but it would be helpful to know which one you're shooting for...

Cheers
_________________
Save the planet: it's the only one with beer!
FrankennBrinkmann ECB
Char-Broil Commercial Gasser
Back to top
View user's profile Send private message
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Fri Jan 28 11 8:50 am    Post subject: Reply with quote

I was just kicking around the idea and hoping for input, didn't know if there was any efficiency to be gained not trying to go super hot just looking to ease up on consumption. hope this clears the subject up a little.
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
Michael B
BBQ Pro


Joined: 31 Aug 2006
Posts: 789
Location: Amherst, New Hampshire

PostPosted: Fri Jan 28 11 6:22 pm    Post subject: Reply with quote

It is going to take the same BTUs to heat the air from ambient to cooking temps, whether you do it in one stage or multiple stages.
Depending on your cooker type, you could try ducting intake air through a heat exchanger in your exhaust stack. That would let you reclaim some of the BTUs that are going up with the smoke, but I'm not sure how many.
You could use something like this.
Only part of the fuel you are burning is making heat to cook your food, the rest is just heating the atmosphere around your cooker. If you are just looking for fuel efficiency, you might be better off isolating or insulating your cooker.
It has been a while since I was in your part of the country, but I do remember it gets plenty cold in the winter, AND that it was pretty breezy. Have you tried sheltering your cooker with wind blocks, or using thermal blankets?
Back to top
View user's profile Send private message
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Sat Jan 29 11 9:13 am    Post subject: Reply with quote

Quote:
It is going to take the same BTUs to heat the air from ambient to cooking temps, whether you do it in one stage or multiple stages.
Depending on your cooker type, you could try ducting intake air through a heat exchanger in your exhaust stack. That would let you reclaim some of the BTUs that are going up with the smoke, but I'm not sure how many.
You could use something like this.
Only part of the fuel you are burning is making heat to cook your food, the rest is just heating the atmosphere around your cooker. If you are just looking for fuel efficiency, you might be better off isolating or insulating your cooker.
It has been a while since I was in your part of the country, but I do remember it gets plenty cold in the winter, AND that it was pretty breezy. Have you tried sheltering your cooker with wind blocks, or using thermal blankets?

I use a wind break and a shelter, I'm just going to insulate my next smoker and drop this Idea all together, I have read somewhere a guy made a hollow fire grate and ducted some air thru that IDK, seems like a cool idea!
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
Michael B
BBQ Pro


Joined: 31 Aug 2006
Posts: 789
Location: Amherst, New Hampshire

PostPosted: Sat Jan 29 11 12:33 pm    Post subject: Reply with quote

jigsnpigs wrote:
I have read somewhere a guy made a hollow fire grate and ducted some air thru that IDK, seems like a cool idea!

Not sure exactly what you are saying, but I can think of three setups that would fit your description. Each sounds workable, until you think about what is going on.
1. Intake air is brought in through the tubes and heated by the fire before being released into the firebox. He is still using the same fire to heat the same volume of air, sufficiently to maintain the desired temperature to cook his food. He might as well put a divider in his firebox and build a small fire on each side of it. One fire near the intake can heat the air as it comes into the ..... warming chamber, which then goes around the divider to feed the cook fire, which will clearly be a smaller fire than he used to need. Net gain is zero, but it is better than the other two designs.
2. He is bleeding off energy through the ducts that would have been going to the main chamber to cook his food, and using it to preheat air that would have been heated directly by the same fire to cook the food or be recycled to preheat more intake air. Kind of like the tubular fire grates you can get for your home fireplace.
2.a. If he is ducting the warming air overboard, he is dumping heat from the fire before it gets to the cooking chamber, and is going to have to build a bigger fire (more fuel) to compensate.
2.b. If he is not dumping it overboard, then he is feeding the fire, in part, with air that has already fed the fire once, thereby lowering the oxygen level in the firebox. His fire will be burning less efficiently, and again he will have to compensate with more fuel.
To make the smaller fire idea workable, you are going to have to come up with a way to loose less radiant heat, or reclaim exhaust heat.

On the side of loosing less radiant heat:
Have you considered a RF design with the firebox moved into and under the air path under the cook chamber. I don’t know if I am saying that right to be understandable.
If you are making a RF cooker, with a two foot square firebox on the left side of the cooker, move the fire box two feet to the right, placing the top of the firebox a few inches below the diverter plates. The radiant heat that would have been lost out of the top of the firebox to the atmosphere will now be used to heat the air in the cooking chamber. You might even be able to duct ambient air across the top of the fire box to combine with the hot smokey air coming out of the other side of the firebox. That would reduce the hotspot above the relocated firebox within the cook chamber, and KIND OF do what you were asking when you started this thread.
Okay, now my head hurts.
Back to top
View user's profile Send private message
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Tue Feb 01 11 10:43 am    Post subject: Reply with quote

thanks Michael B, I bet your head does hurt! lots of good input! I think if you can reclaim heat loss from radiant loss only gain will happen, like you said its a use it or loose it situation.

What if you duct air around the fire box using a double wall construction? , the heat you would gather would have been lost otherwise , also my 24x24 firebox is tucked way under my tank just for these reasons.

Check out my build "200 gal RF taking shape" you might get a better Idea of whats going on with this build.
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
Smokin Mike
BBQ Super Pro


Joined: 02 Dec 2008
Posts: 3142
Location: Winston-Salem, NC

PostPosted: Wed Feb 02 11 6:45 am    Post subject: Reply with quote

Here's a pre-heater for ya....


Actually this guy built it to warm up his swimming pool.
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Rockpyle
BBQ Fan


Joined: 15 Jun 2010
Posts: 141
Location: Canton, MI

PostPosted: Wed Feb 02 11 6:57 am    Post subject: Re: any clever Ideas out there for preheating intake air? Reply with quote

jigsnpigs wrote:
has anyone done this with success ,or is this just flat out unnecessary?


I think I see where you are going. If your draw is strong enough, I think you could set an intake tube under the firebox that would seal to the stock air intake. The tube would be heated by the waste heat of the firebox and would warm the air prior to its entry to the firebox, reducing the thermal work required to heat that air to cooking temps.

I essence, you would reclaim some of the waste heat. It would also potentially prevent wind from impacting the intake (either positively or negatively).


Rock
_________________
**************
Brinkmann Square Vertical
Refurbed Charbroil Silver Offset

Homebrewing and Barbecue Extraordinaire!
Back to top
View user's profile Send private message
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Wed Feb 02 11 7:53 am    Post subject: Reply with quote

Rockpyle, you're dead on brother reclaim is the name of the game, also like you said wind is no longer a concern. And when you live in western Oklahoma this is a concern, more like a consistent evil Mad

My plan is to double wall my fire box just like you were gonna insulate it but instead pull your intake thought this space, I suppose you can reclaim well over 50% of the heat that normally would have been lost into the atmosphere.

Just thoughts...Wink
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
Teleking
BBQ Super Pro


Joined: 26 Sep 2007
Posts: 4139
Location: Maine

PostPosted: Wed Feb 02 11 9:51 am    Post subject: Reply with quote

However, is it a wash with preheating and expanding the air that has less oxygen for combustion compared to cooler air with more oxygen for efficiency?

As stated think “intercooler”
_________________
“Franken Smoker”

“The Bride of Franken Smoker”
Back to top
View user's profile Send private message
Get Your Rub On BBQ
BBQ Fan


Joined: 12 Oct 2008
Posts: 333
Location: Cordova, TN

PostPosted: Wed Feb 02 11 10:19 am    Post subject: Reply with quote

I am actually doing this as a feature in our new smoker. Still working on the design/details but will post more as we get things wrapped up.
_________________
James Stephens
Extreme BBQ Trailers
www.extremebbqtrailers.com
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Teleking
BBQ Super Pro


Joined: 26 Sep 2007
Posts: 4139
Location: Maine

PostPosted: Wed Feb 02 11 10:22 am    Post subject: Reply with quote

Get Your Rub On BBQ wrote:
I am actually doing this as a feature in our new smoker. Still working on the design/details but will post more as we get things wrapped up.


Really! Even after considering the laws of physics?
_________________
“Franken Smoker”

“The Bride of Franken Smoker”
Back to top
View user's profile Send private message
Get Your Rub On BBQ
BBQ Fan


Joined: 12 Oct 2008
Posts: 333
Location: Cordova, TN

PostPosted: Wed Feb 02 11 10:28 am    Post subject: Reply with quote

Teleking wrote:
Get Your Rub On BBQ wrote:
I am actually doing this as a feature in our new smoker. Still working on the design/details but will post more as we get things wrapped up.


Really! Even after considering the laws of physics?


I'm not doing it to fuel the fire, that's taken care of already. I'm doing something similar to act as a "convection" style feature without the use of internal fans.
_________________
James Stephens
Extreme BBQ Trailers
www.extremebbqtrailers.com
Back to top
View user's profile Send private message Send e-mail Visit poster's website
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Wed Feb 02 11 11:05 am    Post subject: Reply with quote

Get Your Rub On BBQ, I'm glad my ideas could inspire you! JK
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
jigsnpigs
Newbie


Joined: 17 Jan 2011
Posts: 86
Location: Elk City, Oklahoma

PostPosted: Wed Feb 02 11 11:15 am    Post subject: Reply with quote

I believe that slightly heating/expanding the air in an indirect manner does not depreciate the oxygen level at all in fact might even create a supercharging effect.
_________________
http://www.thesmokering.com/forum/viewtopic.php?t=47471
http://www.thesmokering.com/forum/viewtopic.php?t=47306
Life is too short to eat bad BBQ
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    The Smoke Ring Forum Index -> Cookers All times are GMT + 8 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2002 phpBB Group