Folks,
I know that forced air seems to be at the bottom of the preference list for heating solutions. But I’m hearing about these new systems that include a water coil that runs through the ducts and is supposed to improve the forced air solution. I think this is one of them:
http://www.woodboilers.com/forced-air.asp
Does anyone have any opinion on them and just how much they improve the forced air systems?
It almost seems as if I can combine this with regular baseboard heating and use this solution only where I can’t fit any baseboards. I wonder if that would make sense.
(I have a large area with not enough wall space for baseboard heat. I am considering radiant but am concerned about temp and humidity swings damaging the wood floor when I turn the heat down when I leave (vacation home). There is another thread going already on that topic).
Bill
Replies
Dunno where you get the idea that forced air is at the "bottom of the preference list".
happy?
Just from what I've read and people I've talked to. I don't have anything scientific (and I won't touch the "dry air" debate :-) ).
I guess I remember hearing that, since there is nothing to hold heat and radiate, it cycles on and off alot and that temps fluctuate more between cycles. I think I've also read that it less efficient to move heat around the house by pushing it around with air than with water. And also that there may be more loss when ducts pass through unheated spaces. But I guess that's a matter of insulating the ducts well?
Bill
In a properly designed installation the ducts don't move through unheated space, or are thoroughly insulated. And in an enclosed area heat is heat, it doesn't really matter where it comes from.
If ignorance is bliss why aren't more people
happy?
Bad forced air beats bad hot water. Good hot water beats good forced air.
With hot water, you can match the input to the heat loss. Can't do that with air.
Downside.... owners hate to pay for proper controls and installation.
"Bad forced air beats bad hot water. Good hot water beats good forced air."
Very well said. Also hot water can be much less intrusive. It takes an 8"x 14" air duct to carry the same BTU's of heat as can be carried in 3/4" of pipe. Which hole would you rather cut to run through your floor joists!
Comfort is derived from from having no air blowing on you, directly or otherwise. Air stratification is virtually eliminated. It can be zoned as much as your wallet wants. No blowing dust around. Doesn't dry out the air. Nice comfortable surface temps throughout your house. In fact my bare feet are nice and toasty as I sit here at my computer typing in my tiled four seasons room and the outdoor temp is at 18 degrees, room air temp is 68! You just don't get that with forced air.
"Doesn't dry out the air. "And how does FWA "dry out the air" more than radiant heat.Use a psychrometic chart to explain.http://ohioline.osu.edu/aex-fact/0120.html
Nice regurgitation from Siegenthaler's "The Hydronics Toolbox".
Based on these statements " No blowing dust around. Doesn't dry out the air." I have to assume that you really don't know anything about air or humidity, or for that matter, dust. Your feet may be warm, but your BS wethead vs "scorched" air mudslinging mantra is old and cold.
If some has dust bloweing around their house, cleaning is in order. Don't blame the furnace. Matter cannot be created or destroyed (ask anyone that passed a high school physics class) and that includes furnaces. Air that leaks into an occupied space that is at 100% rH at 18 degF has an rH of 10% at 68 degF, whether heated by means of hot water inside of tubes of by means of hot gas inside of tubes.
I am a proponent of hydronic heating systems, including radiant floor heating. I know both water systems and forced air systems very well. Both systems have their benefits and their drawbacks.
IT IS POSSIBLE for wetheads to promote the benefits of hydronics without making up bull$hip "examples" of how bad forced air systems are in comparison. However, you have to be a little smarter than your pipe wrench to do so. You discredit the real hydronics professionals by spouting such garbage.
But if you are going to have central air, then forced hot air makes a ton of sense.Jake Gulick
[email protected]
CarriageHouse Design
Black Rock, CT
Tim,
"If some has dust bloweing around their house, cleaning is in order. Don't blame the furnace. "
Every house, in fact every space in the universe, has dust "blowing around.
BUT.
Anywhere there is air movement, there is more "dust blowing around" than there would be without that air movement.
And you wanna blame the HO's wife because your FA unit moves air?
You discredit the real crtitical thinkers by spouting such garbage. (Ironic, ain't it?)
LOL
IT IS POSSIBLE for airheads to promote the benefits of FA without calling wetheads names. However, you have to be a little more curteous than your typical Sawzall user to do so.
SamT
Dust will be created and moving around in the air regardless. A significant proportion of it is human skin, and it gets generated any time the place is occupied. Without a fan to move it around it won't settle as uniformly, but it will still settle.A forced air system will actually help control the dust via its filter.
If ignorance is bliss why aren't more people
happy?
I am neither a wethead nor an airhead. I deal with HVAC systems and equipment of of all types. I was not promoting benefits of FA systems. I was deriding one poster for falsely listing detriments of a type of system he does not promote or understand. I did so discourteously, and I apologize if I have offended your sensibilities.
True, there is dust everywhere, but allowing it to accumulate to noticeable levels inside a house, I would consider that a problem. IF blowing dust is a problem, then in the same home, settled and unmoving dust would also be a problem. In either case, I would not assume that the wife of the HO is to blame. You made that backwards leap all by yourself, however, someone is not keeping a clean house.
Real critical thinkers? about dust in a house? We define critical in different ways, appearantly. This is just for S&G.
Does the humidity change? It depends. Check this out. It is from Heatinghelp.com
AKA the Wall.
Absolute and Relative Humidity by Professor Eugene Silberstein
December 8, 2005
View Image At a recent seminar a question was raised about the widely-accepted statement that forced air heating system dry out the air as it passes through the heat exchanger.
Is this, in fact, true?
Well, the answer is that it depends. On What? Glad you asked.
If, by drying out the air you are referring to an actual reduction in the moisture content of the air, the answer is no.
In a nutshell... When air is heated, the amount of moisture contained in an air sample (as water vapor) remains the same. After all, if water is heated, what do we get? WATER VAPOR! So, if water vapor turns to water vapor (no change) the amount of water vapor in the air as it enters the heat exchanger is the same as the amount of water vapor in the air being supplied to the occupied space. The actual amount of water vapor in an air sample is referred to as ABSOLUTE humidity, and is measured in grains per pound of air or as grains per some unit volume. It takes 7,000 grains of moisture to make 1 pound of water.
So far so good? Great!
So.... what does happen to the air and why do we get that feeling of dryness? Why does my furniture crack? Why do I get nosebleeds in my house?
Although the ABSOLUTE humidity does not change, the RELATIVE humidity does. Okay, time for some quick definitions. As we mentioned, the actual amount of moisture in an air sample is referred to as absolute humidity. Relative humidity is a little more involved.
Relative humidity is the ratio of the amount of moisture in an air sample (multiplied by 100) divided by the air sample's ability to hold moisture (at saturation). For example, if an air sample has the ability to hold 80 grains of moisture but is only holding 40 grains, the relative humidity is (40/80) x 100 = 50%.
Okay, okay... But what does this have to do with that dry feeling on my skin? Hold on... we're getting there.
Now, as an air sample is heated, the air's ability to hold moisure increases. Think of a kitchen sponge that is completely saturated with water. By saturated I mean that, if you placed one more drop of water on that sponge, it would drip from the bottom. Completely saturated. Now, the amount of water in the sponge is well, the amount of water in the sponge and the total amount of water the sponge can hold is the same as the amount of water in the sponge since we said that the sponge is completely saturated. The relative humidity is, therefore, 100%.
Now, wave your magic wand over the sponge to double its size. Now, the waving of the magic wand does not increase the amount of water in the sponge, but only the size (and water holding capability) of the sponge. Now the relative humidity in the sponge is only 50%, since the sponge's ability to hold water has doubled, but the amount of water in the sponge remained the same.
We proceed.
As air is heated in a forced air heating system, the air's ability to hold moisture increases while the actual amount of moisture in the air sample remains the same. This causes the relative humidity to drop. Since the air can now hold more moisture and our bodies contain a whole lot of moisture, the moisture from our bodies is released to the air. The same hold true with moisture in our furniture, floors, paintings, etc.
So, we use humidifiers on forced air heating systems NOT to replace the moisture that the heating system took away, but to increase the moisture content in an attempt to increase the relative humidity.
Something to think about for all of you chill heads to think about. When air passes over the evaporator coil, have you ever notices the condensate dripping from the coil? Of course you have! Well, as we mentioned before, as air is heated, its ability to hold moisture increases, right. Well, if that's true, when air is cooled, its ability to hold moisture decreases! This moisture is what you and I know to be condensate.
Have fun!
True,But that is not restricted to forced air heating.EXACTLY the same thing happens when he is introduced from radiators, radiant heat, or having the kid jump around enough to warm the air.
...or having the kid jump around enough to warm the air.Except that the kid sweats and adds a little bit of moisture that way.
Tim,
I would enjoy a discussion about the relative merits of FA vs RH, having had no experience with either.
A discussion about the stupidity of a BTer isn't my idea of educational.
I define vritical thinking as in Einstein , Da Vinci, and Hawking, not Bunker.
Edit: Oops, forgot. You're argument that if the FA is blowing dust around is a problem of housekeeping is an admission that FA does blow dust around. That's not critical thinking.
SamT
Edited 3/15/2006 10:36 pm by SamT
"A discussion about the stupidity of a BTer isn't my idea of educational."
I wasn't "discussing it" or trying to educate, simply making an observation. I sometimes challenge people posting incomplete or incorrect information as if they knew what they were talking about. My responses to such is usually inapproporiate, as any regular BT'er can attest. OK, so my bad. Nonetheless, if someone poses as if they are an expert and then dispells misinformation or complete bunk, a negative response is likely to follow.
My forced air system doesn't "blow dust around", at least not noticeably. That is the purpose of the large media filter in the return and my vacuum cleaners. The whole point is that the post I criticized is an exaggeration at best, but in my opinion, a shameful and intentional lie.
"I would enjoy a discussion about the relative merits of FA vs RH.."
I'll start a new thread for this one.
Tim,
I'm not always the most social of people myself, especially before coffee. Usually, a few hours to a few days after the fact, I appreciate it when someone calls me on my behavior.
"I would enjoy a discussion about the relative merits of FA vs RH.."
I'll start a new thread for this one.
That would be nice.
SamT
This might be a good document to start off your discussions on FA vs Radiant
Radiant Mythology, 22 Myths About Radiant Systems
ttp://www.healthyheating.com/downloads/22%20Myths%20about%20radiant%20heating.pdfRB
Mr. Bean,
I have to disagree with your "Myth #17". This is a collection of fallacies. Strawman, slippery slope and red herring, all rolled into one.
If we are to accept your "facts", that any and all furnaces have cracked heat exchangers and are moving around only "contaminated air". You futher go on to use the exaggeration of "excessive air movement" repeatedly. So IF we take the worst case scenario that you have constructed, which cannot exist (see below) then your very far fetched "myth" is still debunked by your own words.
You circle back around and explain that a "really talented" designer can take care of this problem with exhaust (which is by the way moving air) and by bringing in the fresh air slowly (which is also moving air).
The actual facts are that moving air is required for good air quality, though excessive air movement is not. Cracked heat exchangers are an uncommon failure of modern furnaces, as likely (or much less actually) to occur as a failed boiler draft hood. IF a heat exchanger were cracked it would leak clean air into it rather than products of combustion out because the hot gasses within a heat exchanger are always at a lower pressure than the discharge of the fan, which is the configuration in a typical gas furnace.
The true myth is that you can have good air quality WITHOUT moving air.
As one professional to another, I claim this type of propaganda is beneath you. I would advise you revise your misstatements to reflect some semblence of reality. If you need technical advise on the operation of the systems you wish to discredit, ask, it is available.
Regards,
Tim
Just one out of 22, that's not bad...(grin)If we are to accept your "facts", that any and all furnaces have cracked heat exchangers and are moving around only "contaminated air". I couldn't find where the article said, [your words - "all furnaces have cracked heat exchangers and are moving around contaminated air."] What it does say is,"... old furnace which unbeknownst to you - has a cracked heat exchanger and is sucking combustion gases into the air moving around your house..."
You futher go on to use the exaggeration of "excessive air movement" repeatedly. So IF we take the worst case scenario that you have constructed, which cannot exist (see below) then your very far fetched "myth" is still debunked by your own words. I did a word count and out of 5100 words, ‘excessive air” is used twice. Tim, you are entiltled to read into the Myth 17 whatever you like…based on ASHRAE research work what the majority of humans like is air velocities between 20 fpm at 70 deg F up to 60 fpm at 76 deg F. When air systems are designed without this in mind, the occupant will consider higher velocities in winter to be uncomfortable.
You circle back around and explain that a "really talented" designer can take care of this problem with exhaust (which is by the way moving air) and by bringing in the fresh air slowly (which is also moving air). Yes… “Really talented radiant based HVAC designers and installers can exhaust the bad air and bring in the fresh air just like a slow moving creek…calm, steady, silent - unnoticeable.” Those are my words…and your point?<!----><!---->
The actual facts are that moving air is required for good air quality, though excessive air movement is not. Yes…and where does it say that air movement is not required?
Cracked heat exchangers are an uncommon failure of modern furnaces, as likely (or much less actually) to occur as a failed boiler draft hood. Yes…which is why the word ‘old’ was used…
IF a heat exchanger were cracked it would leak clean air into it rather than products of combustion out because the hot gasses within a heat exchanger are always at a lower pressure than the discharge of the fan, which is the configuration in a typical gas furnace. If this were always true then there would be no need to replace cracked heat exchangers…from what I understand you are saying, you believe it’s not possible in a natural draft furnaces with a cracked heat exchanger to have higher pressure in the combustion chamber than in the air steam? Sorry Tim, we've measured negative pressure in homes with furnaces blowers operating. Bernoulli also defined conditions with air flow over an orfice creating a low pressure zone within a high pressure stream...Sorry Tim, there are too many variables to say that it can’t happen when it does happen.<!----> <!---->
The true myth is that you can have good air quality WITHOUT moving air. Tim…not sure where you’re going with this but it’s your journey have fun. <!----><!---->
As one professional to another, I claim this type of propaganda is beneath you. I would advise you revise your misstatements to reflect some semblence of reality. If you need technical advise on the operation of the systems you wish to discredit, ask, it is available. Thanks for your offer Tim…perhaps after you reread the entire text including this exceprt,
(IAQ) Indoor Air Quality + (ICQ) Indoor Comfort Quality = (IEQ) Indoor Environmental Quality,<!----><!---->
<!----> <!---->
Most who study the materials would conclude our position is not an air vs water debate…we integrated in our teachings both systems are required as a means of delivering on 'all' aspects of human comfort and health. See this link if you doubt.
(http://www.cmxciphexshow.com/seminars.cfm)
Radiant can’t deal with IAQ issues, (de) humidification, exhaust heat recovery or latent cooling. Air systems can’t effectively address radiant losses from the body, (a nominal 55%), cold floors, radiant asymmetry, or vertical temperature differences which water based systems or efficient construction is very good at. If you share this conclusion we would be happy to consider your offer…we’re always looking for professionals to volunteer their time, talents are writings.
RBeanhttp://www.healthyheating.com
Edited 3/20/2006 12:30 pm ET by RBean
"Just one out of 22, that's not bad..." The old wives' tales and other nonsense are not ineresting enough (to me) to go into. Don't mistake that as "not bad".
"Yes…and where does it say that air movement is not required?" The title of the myth is "You Need to Have Air Movement for Indoor Air Quality", is it not? Therefore, you made the statement, that the following "You Need to Have Air Movement for Indoor Air Quality", is a myth. This is a simple logical progression. Do you disagree that this is what you stated? Am I misinterpreting your "myth"?
By your response and defense of your myths, you are claiming that all of you statements are true, fair and representative of actual installations, and accurate to the best of your ability and/or knowledge? Or do you acknowledge that you have exagerated somewhat in your attempt to promote yourself and your business?
"…from what I understand you are saying, you believe it’s not possible in a natural draft furnaces with a cracked heat exchanger to have higher pressure in the combustion chamber than in the air steam?"What I said is that the pressure in the clean (i.e.supply) air stream is greater than the pressure inside the heat exchanger, while the furnace is opearing in an acceptable manner. This is a true statement weather the HX is cracked or not. A natural draft or induced draft furnace operates on a negative pressure in the combustion area. This is the only way to have flow through the heat exchanger. Atmospheric pressure at the inlet where the fuel and air are mixed, negative pressure throughout until either the discharge of the flue or the discharge of the draft inducer.
" ...we've measured negative pressure in homes with furnaces blowers operating. " Having measured negative pressures in homes has nothing to do with the relative pressures inside and outside of the heat exchanger while a furnace is operating. IF what you were trying to say, is that you have measured the two pressures as I have described, (the pressure inside of the heat exchanger and the air pressure immediately adjacent to the heat exchange during furnace operation) both of which are completely and entirely within the furnace cabinet, then I have misunderstood your statement. You further go on to again construct an unlikely (though I will admit possible within the laws of physics) scenario in which a "low pressure zone" would exist in a furnace heat exhanger. Do you know the average velocity of air through a furnace? Do you know how much flow area reduction is affected in the heat exchanger region of an old inefficient, natural draft furnace?
"Bernoulli also defined conditions with air flow over an orfice creating a low pressure zone within a high pressure stream...there are too many variables to say that it can’t happen when it does happen." Flow is through, not over an orifce. Maybe an "insignificant" detail, but one you missed. There is no "low pressure zone" in a high pressure stream. When a fluid flows though an orifice, some of the pressure energy is converted to kineteic energy and is related in a simple formula. Your statements indicate that you do not understand this very well.
"Air systems can’t effectively address radiant losses from the body, (a nominal 55%),.." Were this a true statement, every single forced air heating system on the planet would be ineffective at providing comfort heating, which is incoorect. You can easily cite examples of poor installations in which FA systems are drafty, ineffective and uncomfortable. However, effective comfortable forced air systems are installed every day.
"Most who study the materials would conclude our position is not an air vs water debate…" With the exception of Myth #17, I would concur with that. However, all must be taken into account to make that assessment, not just select materials.
PART 1 OF 2
The old wives' tales and other nonsense are not ineresting enough (to me) to go into. Don't mistake that as "not bad". Good…as it should be - we all get to choose what is important and interesting. You’ve decided to pick something that you are passionate about…I’m looking forward to learning from you.<!----><!----><!---->
Am I misinterpreting your "myth"? Yes and no…I’ll give some thought to your observations and consider rewriting the title to reflect what we hear consumers often say after talking with a sales person…here are our favorites: “We want to have (a furnace, fan/coil) so we can have good indoor air quality.” “We heard that without a forced air system the IAQ will be poor.” “We heard you have to move the air around to have good air quality”<!----><!---->
For what ever the reason, many consumers, who live in areas of the country without ventilation codes, assume circulating air improves IAQ. That is just wrong. Since IAQ is such a large topic it’s too simple to conclude that have air moving around the house will address all the issues. Along the same lines would be the installation of fresh air intakes located next to a source of contaminated air...the consumer makes the assumption that since air is being exhausted and outside air being brought in that it must be good…<!----><!---->
If you can see where we’re coming from on this then hopefully with a rewrite of the title the unsuspecting consumer will think twice about the sales pitch for air flow and IAQ which are both independent and integrated topics.<!----><!---->
“By your response…” I appreciate your candor but you have only taken issue with one myth and as suggested above we will consider your comments on that specific one. Thank you. If you wish to challenge the others for their truth, fairness and representation then we’ll address each on its own merit and because we value your comments will consider revising if there is merit in your observations. As far as the promotion and business comment you’ll have to provide an example of the benefit since the content and materials are developed by volunteers and made available free to anyone who chooses to benefit from its exisitance. As to the tone of the entire article, it is meant to poke fun at the information, which floats around the industry. If you’re looking for more serious peer reviewed technical materials which caters strictly to engineering applications then you can download those from the site as well. Again, we always welcome challenges from any visitor to the content since ultimately it improves the materials. <!----><!---->
“opearing in an acceptable manner.” Yes, we understand that, but we are not addressing perfectly operating equipment. We were addressing the operation of imperfect equipment and assuming it was delivering good IAQ. <!----><!---->
“ within the laws of physics…” We would welcome an article on this topic if you wish to address the conditions of when its possible and when it is not possible.<!----><!---->
“Flow is through, not over an orifce.” From my recollection a steam jet vaccum pump has flow through a nozzle not an orfice with the motive flow discharging over an orifice into the venturi …. and isn’t air flow over a pitot tube (an orfice) used to measure air speed…I could be wrong or maybe we’re using terms to describe the same thing…it sounds like you have some expertise in this matter. Again, always looking to learn…<!----><!---->RBean
web: http://www.healthyheating.com
Part 2 of 2
“ which is incoorect.” That’s the point Tim, comfort is not a piece of equipment. It’s a physiological experience expressed in a psychological construct. All any mechanical systems can do is try to create a set of conditions allowing the body to exchange heat to maintain an equilibrium in heating or cooling. When the body experiences discomfort its because of the method and quantity of transfer. You’ll have to take up your cause with the research work which documents data with over 50% of occupants being dissatisfied with their environments, which are conditioned, by some form of HVAC system. In <!----><!---->North America<!---->, air systems represent a nominal 85% marketshare. There are other solutions to conditioning people such as improving building efficiency. The more efficient the building the less influence it has on the body’s radiant gains and losses so in effect a warm air system can create the conditions for occupant comfort within these parameters.
Not sure where you see us taking a stance against air based systems. We discuss the relationship between building efficiency, mechanical efficiency and the role they have on comfort ad nasueum in the materials. <!----><!----><!---->
"Most who study the materials would conclude our position is not an air vs water debate…" With the exception of Myth #17, I would concur with that. However, all must be taken into account to make that assessment, not just select materials. <!----><!---->
Yes, of course. That’s why there is 22 Myths and not one. There are many others listed and we’re adding more as they come about. RBean
web: http://www.healthyheating.com
"For what ever the reason, many consumers, who live in areas of the country without ventilation codes, assume circulating air improves IAQ. That is just wrong. "
I agree completely. As I suggested in my original post to you on this myth, some clarification and/or rewording would make you point more clearly, as you have done here. Had I not done so in such a confrontational tone, you probably woudl have seen that.
I believe that you are in a great position to inform people of some facts and to dispell some misconceptions. I believe for the most part that you are doing so. This is why the one myth I noted stood out from the others as distinct (although practical applications on a residential scale of radiant cooling is a stretch as well). I believe that you could make your point about the fact that simply circulating air does not improve IAQ without going, what I consider "out of bounds". No need to comeup with the leaking heat exchanger scenario. The simple fact of recirculating would make the point, with some realistic and common examples of indoor contaminants.
I am a proponent of hyronic systems, and radiant heating systems, as well as of forced air systems. I see and hear terms like "scorched air" frequently from otherwise seemingly intellegent individuals and that level of ignorance will get me spun up most times.
"From my recollection a steam jet vaccum pump has flow through a nozzle not an orfice with the motive flow discharging over an orifice into the venturi …. and isn’t air flow over a pitot tube (an orfice) used to measure air speed…"
A steam jet vacuum pump does pass low pressure steam through a nozzle, which is nothing more than a very smooth orifice, ans creates a low enough pressure to remove the "non-condensables" from an large condenser, such as in a steam electric power station. These nozzles, however, are specifically designed to create the greatest velocity at the throat for the express purpose of being a vacuum pump. This condition is not going to occur in other circumstances by accident. There may be an orifice in the steam supply line to act as a flow limiter (flow through an orifce or nozzle is limited to the sonic velocity of the fluid at the pressure and temperature upstream of the device). A pitot tube immersed in a moving fluid is actually two devices in one. The first part is a tube, the opening of which is directed into the stream parallel to the flow and measures the static and kinetic pressure of the moving fluid. The kinetic pressure of a fluid is the pressure required to stop the fluid from moving and is expressed as the v^2/2g part of Bernoulli's equation. The second part of the device is another tube, usually concentric to the former, in which the opening in the tube is perpendicular to the direction of flow, and measures only the static pressure of the fluid. Given the fluid density, temperature and compressability, you can calculate the flow velocity based on the difference between the two parameters measures. Flow is "past" a pitot, is the best way that I can describe it, though until the stagnation pressure is reached, flow is also "into" the pitot tube.
Edited 3/20/2006 6:16 pm by Tim
No doubt the practical applications of residential radiant cooling is disturbed by the impractical human element (read kids) which like to leave windows and doors open…grin.<!----><!----><!---->
“…will get me spun up most times.”
It gets me going as well…I’ve never been in a truly comfortable hydronic heated home that didn’t have some element of air…even in our own home, we have both. The air system is dedicated to humidity, filtration, and make up air. Both fan/coils are equipped with constant discharge temperature controllers (72 deg F) and parallel override controls for second stage heat (120 deg F) for times when the radiant floor/wall have reached their peak operating temperature at maximum load. Steam is used to maintain constant humidity year round. With constant discharge temperature on the make up air we can humidify without heating and when we need the supplemental heat (7% of the heating season) the secondary stage is engaged.<!----><!---->
“A steam jet vacuum pump …”
What seems like eons ago I participated in a company which handled the S & K line (aka AMETEK/ aka Ketema / aka as the new S & K) of <!----><!----><!---->Bensalem<!---->, <!---->PA.<!----><!----> With your knowledge of jets perhaps you know the history - it makes for fascinating reading involving sons and daughters of the founders (Shutte and Koerting) , the Fisher family (Fisher controls) and military contracts…AMETEK spelled backwards is KETEMA – that story in of itself makes for intriguing materials. Somewhere in my archives is a copy of an old steam jet design which was used to feed water into steam locomotives…this was Koertings first commercial contribution for the ejector / eductor / thermocompressor….if I recall the date was 1886 or 1906 something like that…its been years since I’ve looked at it. It was given to me as a gift from one of the old application engineers who has since passed away. I always loved the simplicity and complexity of these devices.
Thanks for your comments Tim...we'll reword the title and text shortly.<!----><!---->RBean
web: http://www.healthyheating.com
My experience with "jets" was as a system engineer at the Byron Nuclear Power Plant in northern IL. I was the Condensate System Engineer and aslo had the Air Inleakage program. The steam jet air ejectors (SJAE), as they were called there, were responsible for removing air and other non-condensable gases from the main condensers. Every refueling outage, I was afforded the opportunity to inspect these devices in detail to assure they remained within the manufacturer's specifications. The manufacturer of the system, including the SJAEs was Westinghouse.
Will try to find the drawing and will post when I get back in April.
The biggest ones our guys worked on were 12 ft long...they were so noisy ( can't remember the estimated speed of the process steam leaving the nozzle) we had to add mufflers and bird screens...they were used for drawing in mass amounts of air into some process...don't recall the details only the bill for the mufflers and screens!
RBean
web: http://www.healthyheating.com
blog: http://wonderfulwombs.typepad.com
On old Lennox counterflow furnaces, there was a length of angle iron welded just above the heat exchanger creating a negative pressure zone. When a pinhole occured at the very top of the hx, flue gases get sucked out of the hx and into the airstream. Whatever that effect is called, it is possible for a natural draft furnace to leak flue gases into the airstream.
"...it is possible for a natural draft furnace to leak flue gases into the airstream."
I realize that is possible, though in most furnaces made and sold today, very unlikely. The added angle is obviously a poorly done band-aid for a poor product.
I find forced air extremely comfortable. It has a number of advantages besides comfort, as well. If installed poorly it can be as uncomfortable as poorly installed radiant floor or baseboard heat.
BINGO!!!!
"If installed poorly it can be as uncomfortable as poorly installed radiant floor or baseboard heat."
A properly installed forced air system should radiate heat out of the registers. NOT, blow the curtains up to the ceiling.
I had forced hot air until two years ago. We did a complete overhaul of the heating system. Went with Burnhams Radiant Radiators on 4 zones. Each radiator is independently fed and can be throttled down and fine tuned. There is no comparison in my experience. "Don't take life too seriously, you are not getting out of it alive"