Curiosity question.......I don't even knoe if it'd work
Has anyone tried to use infared heat for a bus? Something like the comfortzone 1500 type of unit? Energy costs are supposed to be extremely low and one is rated to heat 1000sq ft of space........so 2u should easily heat my bus..any ideas/concerns/opinions?
I am not (I repeat "NOT") one of the guys who happily shoots down every creative idea suggested...but in this one instance, I have to say I've personally done so much research on these types of heaters...and I know a couple of individuals who have them, and they are truly mostly glorified space heaters. Different approaches, maybe some good, maybe not, but they do do not actually provide more heat/btu's than any other 1500 watt electrical heater. That being said, we super insulated our coach when we built it. This includes 1.5 inch foam, and two layers of Reflectix in addition to the wood/plywood. We have so far used only a single 1500 watt space heater to keep our coach comfortable down into the upper 30's...true story. Consumer Reports has tested several models of the Edenpure heaters, infrared heaters, etc. Here's the most recent article (subscription required to pull it up):
Moderator Edit - Although very good information, the removed content was a copyrighted work posted in its entirety which was a violation of the Consumer Reports terms of use, resulting in a copyright complaint.
Scott,
Thank you for the info..........
the reason I bring it up is I was given two of these heaters by my father who simply doesn't need them.... so I figured it'd be worth a try... but maybe not??
Thank you
Noah and family
Can't beat the price Noah what do you have to lose lol it would be a no brainier for me
good luck
Hahaha faiir enough...... thankks clifford
One thing also to remember is that 1500 watts is still 1500 watts no matter what you try to do with it. It will still only produce a certain amount of heat no matter what the claim is. Just another mfg consumer rip off, especially at that price. Bob Vila should be hung for supporting a rip off like that. They must of used the other $400 of the $472 to pay him off to support it's claims.
Quote from: GMC5303Wonder on November 14, 2011, 07:05:32 PMScott, Thank you for the info.......... the reason I bring it up is I was given two of these heaters by my father who simply doesn't need them.... so I figured it'd be worth a try... but maybe not?? Thank you Noah and family
Well in that case, you were given a couple of 1500 watt heaters. I'd use them in a heartbeat :) I just couldn't justify paying $400 for each of them. We actually use this space heater in our coach. Also 1500 watts, takes up very little space. And it works. Still amazes me:
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Flh4.googleusercontent.com%2Fpublic%2FHfylb-dPO-1C1UzZbtGpSRArCLSwjdJPiFAkzZ0s1_nrUFYFlBXZll0IKA1XVBpi6AGCjrtmeYn2-XqfA2adhhpo0N70AuZzrFxf-bg0vWNL6Nev6ebKwP-9QIYYQFeBBPLlM0gj1X6CsNrhQiG9yizwOAvlV_s-rYDBdr_LaWODSceG&hash=1f4297e23ba3cd5fd92e2b798483703dad5bdfda)
Total ripoffs overpriced BS
Scott-does your bus still not have any windows cut out? That's why you're able to keep your bus warm easily. When you do cut windows, even using double pane windows will let in a lot of cold and heat. You can see by my picture of my bus both my wife and I REALLY like the big huge windows. After all-aren't we travelling to see things? Good Luck, TomC
Quote from: TomC on November 15, 2011, 07:40:11 AM
Scott-does your bus still not have any windows cut out? That's why you're able to keep your bus warm easily. When you do cut windows, even using double pane windows will let in a lot of cold and heat. You can see by my picture of my bus both my wife and I REALLY like the big huge windows. After all-aren't we travelling to see things? Good Luck, TomC
No doubt...and we're wanting windows...trust me. But when we're driving down the road, the windshield and drivers/passenger windows are amazingly panoramic. When we do cut our windows in (double pane as you said) I'll be sure to report the heating/cooling efforts needed at that time. Right now, our front cap isn't even paneled or insulated, neither is our front door (interior skin removed too) and we don't have a heavy curtain to block windshield heat/cooling effects, and we were previously (in Pennsylvania) using a single 1500 watt heater to keep warm down to 30 degree temps (we're in Florida now, so no contest) and a single 13,500 BTU a/c unit to cool the coach in 90 degree temps. Right now, outside (ambient) temp is 84 degrees. We have two thermometers in the coach front and back). I just timed it. To cool the temp from 78 degrees down to 68 degrees in the entire coach (both thermometers reading 68 or below) it takes 25 minutes. No ducting...just one unit at the front of the coach. Works for us.
OK, I'm going to jump in here to clear up some misconceptions, on the part of advertisers and perhaps some folks here following along.
All electric space heaters are 100% efficient, it does not matter whether they are "infrared," "oil filled," "disc furnace," or "mil-spec laser guided." Any claims that one produces more heat than another are simply marketing hype, or outright lies. 1500 watts is 1500 watts is 1500 watts -- and watts is a measure of heat as well as electricity in SI units. In more common parlance, 1500 watts is 5120 BTU/hr (aka "BTU rating").
That being said, there are subjective differences between heaters, and this has to do with where the heat gets directed. So while in a pure sense, each produces the same heat, and a scientist measuring the incremental heat of the container (room) would see exactly the same change no matter which model, a human sitting in the room will experience each type of heater differently.
The "infrared" style of heater projects the heat in a relatively narrow cone in front of the unit. It will warm up whatever is in that cone at the expense of everything else in the room. So if what you want is to be warm while sitting in your easy chair reading a book, and you don't care about the temperature in the rest of the room, this type will be more effective for you. If, OTOH, what you want is to provide an even temperature increase throughout the space, then a type with a circulating fan is probably more effective.
Note also that, while any energy used to spin a fan does eventually become heat, moving warmer interior air around can have the effect of sending more of your precious interior heat right out of the coach, as warm air is moved past poorly insulated surfaces such as windows.
These are the sorts of factors you need to take into account when choosing electric space heaters for your coach, rather than anyone's marketing hype suggesting that one style is "better" than another.
While I am at it, I should probably also point out that you are unlikely to get 1500 watts (or 5120 BTU/h) out of any of these heaters, because they are rated at 125 volts, and your power supply is probably 120 volts or less. A "1500-watt" heater will provide only 1382 watts (4716 BTU/h) at 120 volts, and just 1162 watts (3965 BTU/h) at 110 volts.
Any why are heaters generally rated at 1500 watts? Because that's the largest heater that can be run continuously on a dedicated 15-amp circuit. Household circuit breakers, including the ones in your coach, are designed to carry their "handle rating" only for short periods of time. If you drew 15 amps continuously from a 15-amp breaker, it would eventually trip. Instead, breakers are designed to carry just 80% of their handle rating continuously. Above that, they are supposed to trip over time; the further above the 80% threshold, the sooner they will trip. Above the handle rating, they are supposed to trip "immediately," although a small time delay is permitted for breakers designed to support Heating, Air Conditioning, and Refrigeration equipment, thus designated type HACR.
So that means a 15-amp circuit can continuously support only 12 amps. The heater maker must allow for house voltage of 125 volts, which is the published standard for such things (if you look at the ratings on your receptacles you will see they are rated at 125 volts). 12 amps at 125 volts is 1500 watts, and so that's the largest heater you can make without assuming a larger dedicated electrical circuit.
And now, as Paul Harvey used to say, you know the rest of the story.
One final note: It is, indeed, possible to get more than 1500 watts of heat from 1500 watts of electricity, but not with a portable self-contained space heater. The device which can do this is a reverse-cycle air conditioner, also known as a heat pump. That's because it's not turning electricity directly into heat, but, rather, it is using the electricity to move the heat from one place to another, namely, from outside the coach to inside. They are very efficient, but only down to outside temperatures in the low 40s; below that, it is difficult for a system based on conventional refrigerant to extract enough heat from the outside environment.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Thanks Sean,
That pretty much explains every aspect of that. Good info ;)
My understanding is that these heaters consume 1500 watts, that they don't necessarily produce that much heat, especially if they have fans, but may.
Infra-red heat is like a flashlight beam, it only heats what it shines on. A simplification of what has already been posted.
They are great in large areas like shops when one is working in one spot for a while, that way the heat is not wasted.
The Eden things are ripoffs, they make claims that are scientifically impossible and the price is outrageous. Bob Villa has forever lost his credibility.
We got 2 cube heaters from an estate sale we went to for 6 bucks for the 2. They both work great. We use 1 and at 28 degrees on the river it heats very nicely and we have a back up too. We have a Atwood but haven't used it because it needs a new board but just haven't had time to get one. it eats gas at 35,000 BTU's. So we stick with the electric. We have all our windows still tinted some dual but mostly original slides and 3 inches of insulating foam with 3/8 ply over it, curtains with UV protection. Thick drapes in the front. FWIW
Dave
Quote from: gus on November 15, 2011, 05:28:25 PM
My understanding is that these heaters consume 1500 watts, that they don't necessarily produce that much heat, especially if they have fans, but may. ...
Actually, every watt consumed by an electric space heater in an enclosed space becomes heat; it is impossible for it to be otherwise. It is know as the First Law of Thermodynamics.
For that matter, every watt consumed by a light bulb, electric stove top, or toy train set also becomes heat. In general, in fact, all the electric power going into your coach will become heat inside the coach with three exceptions. One is any motor-driven system that acts outside the coach, for example an air conditioner. To be sure, that energy ultimately becomes heat, too, but it is exhausted outside the coach. Another is any resistive load exhausted or directed outside the coach. Examples include a light which shines out through a window, or the electric element in an absorption fridge. And the third would be an energy storage system, such as a battery bank (where the power will likely still be expended as heat, but at a later time).
So let me reiterate: ALL electric space heaters are 100% efficient. It does not matter whether or not they have fans, or whether they are the infrared type or some other type. The only difference among them is how the heat is directed or dispersed.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Back in the 30's induction cooking would never work I don't own one of the heaters but I am not one to rate something from paper or the internet for me it's garages sales if it doesn't work they will pop up there LOL,people I know that have one love the heater
Noah has 2 that were given to him why not try it then he can tell us if they work hard to believe all this from 2 free heaters,there is more than 1 manufacture of that style heater
Quote from: luvrbus on November 16, 2011, 04:58:12 AM
Noah has 2 that were given to him why not try it then he can tell us if they work hard to believe all this from 2 free heaters,there is more than 1 manufacture of that style heater
i don't think anyone was suggesting he not use them. this was mostly about don't buy a $472 heater when an $80 will work, and a good explanation of why they're all about the same, so stick with the least expensive that suits your purpose. Free is the cheapest. ;D
and Sean, thanks for a better technical explanation of the good consumer information Scott provided. i did not think about the differences voltage would make and why 1500w.
That's not my point Tom everybody here says they don't work but yet Noah is the only person here with one LOL
I guess should read Sean's technical stuff but I don't it is to technical for me but I do read his about his mechanical problems
good luck
Quote from: luvrbus on November 16, 2011, 07:40:50 AMThat's not my point Tom everybody here says they don't work but yet Noah is the only person here with one LOL I guess should read Sean's technical stuff but I don't it is to technical for me but I do read his about his mechanical problems good luck
I vote "YES" on this too. Use them and tell us how you like them...it would be a real data point at least... :)
Just remember "two dogs" ad the electric radiator fans. got free fans and disappeared from the earth. Never did find out if they worked or not.
uncle Ned
Constantly amazed with the wealth of knowledge from everyone on here.
The wife threw one in the bus today...... ill let everyone know how they work...
As far as the price point..... I agree... spend almost 500 bucks on a "portable infared heater" id probablly never do it.... but as said "free is the best price"
Ill let everyone know how it works...... the iowa winter will definately be the test of tests... and if it works here it'l definately work in western washington where we plan on using the bus as a fulltime unit while we work and build our "dream home"
Thanks to everyone for the input I greatly appreciate it!
Noah and family
A minor point, but not all electric energy used in a coach is converted to heat. Per the previous example, a coach's fans and its model electric trains are converting electric energy to mechanical energy, or work, and not heat energy; same goes for many other loads. Granted, in the change to mechanical energy some minor heat losses are seen, but not all of the electrical energy is 100% converted to heat.
But yes, the simple old rugged $12.00 milkhouse heater is every bit, 100%, as efficient as heaters with tons of advertising energy packed in them.
Ted
Quote from: TedsBUSted on November 16, 2011, 06:15:49 PM
A minor point, but not all electric energy used in a coach is converted to heat. Per the previous example, a coach's fans and its model electric trains are converting electric energy to mechanical energy, or work, and not heat energy; same goes for many other loads. ...
Sorry, Ted, but that's not entirely correct.
Yes, a mechanical device such as a motor converts electrical energy into work. However, that work is then converted directly back into heat inside an enclosed space, which scientists would refer to as a "black box". The work only leaves as something other than heat if it can act outside of the black box, or, in this case, the coach.
For example, if you put a fan -- no heater, just a fan -- into an insulated box with a temperature probe in it, and measured the rate of rise of the air temperature inside, you would see that every watt-second of energy going into the fan becomes heat inside the box. In fact, you can not tell whether what is connected to the wire is a fan or a light bulb -- 1 kWh consumed by either will add 3412 BTU to the box.
The same thing is true for the electric train -- all the "work" done by the train is against friction on the track, and work expended against friction becomes heat, plain and simple. In the case of the fan, the air movement itself represents some heat (remember that heat is nothing more than molecular motion), and the air then moving against all of the surfaces of the box becomes heat through friction.
This is why I wrote earlier that any motor must act outside the coach for that energy not to become heat inside the coach. I also said that energy going into a storage system, such as a battery bank, will not become heat, so you could also have a motor that, say, wound a clockspring, or pumped water from a lower tank to a higher one, and that work would not become heat either -- but that's not what happens with the fan inside a heater.
Hope that clears it up.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Sean, I respectfully disagree with your take on the heater's fan load. Although we're getting into a hypothetical that really doesn't matter, I will cover a bit of it. I think our difference lies in the fact that I don't believe that a bus is a "tight" enough enclosed space to have "black box" status and thus to apply the "captured" energy theory.
Once the hypothetical fan would be removed from the black box and put to work blowing air around the coach, the same fan's motor will show a higher amp draw. This increased amp draw represents electrical energy being converted to "work" moving air, and is not electrical energy simply being converted to heat through frictional losses or otherwise. An ammeter and a cardboard to slip over almost any fan's air intake side would quickly demonstrate this.
Anyway, for all practical purposes I can't find any logic in considering a bus to be an "island" of energy any different from, or separate from, the rest of the universe. Actually I wish I hadn't mentioned it and I'd just as soon forget about it. ;)
Ted
Quote from: TedsBUSted on November 16, 2011, 10:10:09 PM
... Actually I wish I hadn't mentioned it and I'd just as soon forget about it. ;) ...
That's fine, and if you and I had had this conversation privately in email or PM, I suppose we both could. But there are already 23 people following along, and there may be hundreds more who visit this topic in the archives over the years, and at least some of those folks want to know the right answer. My purpose here is not to beat you up -- your mistake is a common one and I've heard it many times. Rather I am simply trying to shed light on a rather esoteric subject that, it turns out, affects coach converters in several ways.
Quote
... Although we're getting into a hypothetical that really doesn't matter,
Well, actually, it does matter. It bears on the original discussion, wherein a manufacturer has asserted that his product is somehow more efficient than someone else's, which is a physical impossibility (my original assertion), and which was then also challenged by a respected consumer watchdog publication. But it also has a bearing on other facets of coach conversion; for example, folks here ought to know that every electrical device in their coach adds its total wattage to the coach's heat load (with the exceptions I already noted). That becomes important when planning for air conditioning, for instance.
Quote
I will cover a bit of it. I think our difference lies in the fact that I don't believe that a bus is a "tight" enough enclosed space to have "black box" status and thus to apply the "captured" energy theory.
Well, first off, it's not a "theory." As I said, it is the First Law of Thermodynamics, a law which has been around for much longer than you and I and is immutable. We call them Laws for exactly this reason. By contrast, Gravity, like Evolution, is a theory and we can debate it (although I don't expect to fly off the Earth any time soon) :)
With regard to the "tightness" of the coach, please note that I already mentioned this. In fact I explicitly said that units with fans were subject to actually moving the warm air past cold (or leaky) surfaces. So, no, it is not the same as the black-box experiment, but that does not change the fact that every watt still becomes heat first, even if later it finds its way outside through a leak.
Quote
Once the hypothetical fan would be removed from the black box and put to work blowing air around the coach, the same fan's motor will show a higher amp draw.
Actually, no. The black-box experiment is not dependent on the box being small, it can be any size -- as large as a bus. Blocking the fan's air flow, in fact, will not lower the current, but rather it will raise it as the fan struggles to move air against constraints. Anyone who works with HVAC systems can tell you that the load on the fans increases as the filters become more restricted, for example. But the point behind the black-box though experiment is not to equate a coach with the black box, but rather to illustrate that all the energy becomes heat -- true even if you take the black box away completely.
Quote
This increased amp draw represents electrical energy being converted to "work" moving air, and is not electrical energy simply being converted to heat through frictional losses or otherwise.
Let me say it again: The electrical energy is not all being converted to heat directly -- you are correct, much of it is first converted to work. But 100% of that "work" MUST then become something else, according to the First Law. There are not a lot of choices for the something else: it can be stored, such as in a battery, spring, raised weight, etc. as I already said; it can leave the coach as "work" but only through some mechanism to do so such as a shaft protruding outside of the coach to drive something external (pretty far afield from a space heater), or it can become heat. In practice, it ALL becomes heat.
Quote
An ammeter and a cardboard to slip over almost any fan's air intake side would quickly demonstrate this.
Challenge accepted :) Come to my next seminar, and I will bring the appropriate tools -- a fan, a lamp, a pyrometer, an ammeter, and an ice chest, and I will demonstrate to you experimentally that the First Law can not be violated. Note that you need the entire setup -- having just the fan and the cardboard is not a closed system and will not give accurate results.
Quote
Anyway, for all practical purposes I can't find any logic in considering a bus to be an "island" of energy any different from, or separate from, the rest of the universe.
Nobody said it was an "island" or that it was "separate from ... the universe." I merely said it was a closed system. And, though you can find no logic in it, it is the engineering basis for many things, such as computing the required amount of cooling to deal with internal heat loads. But the reason I made the statement in the first place was to clear up the marketing-generated misconception that any one 1500-watt electric space heater can be more efficient than any other 1500-watt electric space heater -- it simply can not: each will produce precisely 1500 watts of heat.
This is very definitely a real-world concept. One of the things that I did back when I was working was to design large-scale computing facilities. Lots of fans and other motors in such places -- every computer and every cabinet has fans, and every disk array has lots of motors. All of those fans and motors are doing "work" -- and every joule (or, if you prefer, foot-pound or maybe horsepower-hour) of that work ultimately added directly to the heat load. If we put 200kW of electricity into the room, we knew we had to take 682,500 BTU/hr of heat out (or about 57 tons of cooling) before we even factored in any other loads such as personnel.
This concept is every bit as relevant in a bus. If you put 3kW of power into your coach, no matter what it's running -- microwave, fans, lights, television, water pumps, coffee maker, household fridge, or even a toy train set. -- you'll be adding over 10,000 BTU/h of heat to the coach, with the exceptions I already noted (air conditioners, exhaust fans, externally-vented heating elements, etc.) If you happen to be doing this in the summer, that's another 10,000 BTU/h of air conditioning you'll need just to break even.
Again, I hope that clears it up.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Quote from: TedsBUSted on November 16, 2011, 10:10:09 PM
... Actually I wish I hadn't mentioned it and I'd just as soon forget about it. ;) ...
Quote from: Sean on November 16, 2011, 11:53:02 PM. . .there are already 23 people following along, and there may be hundreds more who visit this topic in the archives over the years, and at least some of those folks want to know the right answer. My purpose here is not to beat you up -- your mistake is a common one and I've heard it many times. Rather I am simply trying to shed light on a rather esoteric subject that, it turns out, affects coach converters in several ways.
Sean, First off I'm not afraid of being wrong and am more than willing to admit a mistake. However, on the other hand I don't want you to feel like I'm beating you up by carrying on. The reason I said I'd like to drop it is not because I'm afraid of being wrong, but because a rather minor point is getting blown out of proportion. So with that out of the way, if you insist, let's get this hair split.
We are in agreement on almost everything, but what originally raised my eyebrow was your contention that the current drawn by a fan motor is being converted to heat, rather than work. You asserted that view again with the "black box" analogy and now you've underscored it with a restricted filter scenario.
QuoteBlocking the fan's air flow, in fact, will not lower the current, but rather it will raise it as the fan struggles to move air against constraints. Anyone who works with HVAC systems can tell you that the load on the fans increases as the filters become more restricted, for example. But the point behind the black-box though experiment is not to equate a coach with the black box, but rather to illustrate that all the energy becomes heat -- true even if you take the black box away completely.
My point is that a fan motor converts energy to actual work and not simply to heat. It's a misconception to think that a "choked" fan's motor draws more current. (
Until you can run an actual experiment to prove it to yourself, please humor me and play along.) In fact the exact opposite is true. A fan with a restricted flow path draws less current, because it is doing less work. Less work because the electrical energy a fan motor draws is normally being converted to work, and not to heat. A "choked" fan can not convert electrical energy to make any appreciable amount of heat, or to do its usual work, and thus the motor's current draw drops.
In summary, my minor, simple, concise point is that the portion of an electric unit heater's current draw which feeds the fan motor is NOT converted to heat energy, but to work, in the form of moving air. Yes, someday when the universe implodes maybe the fan's work will become heat again. In the meantime, with a real-world practical application I'll say that a typical fan motor located aboard a coach is not adding appreciably to the coach's heat load, (very minor inefficiency loses aside) while adding greatly to the interior's comfort level.
Ted
Be aware that when heating your bus with an electric heater, it can get expensive.
I broached this issue in this thread:
http://www.busconversions.com/bbs/index.php?topic=22056 (http://www.busconversions.com/bbs/index.php?topic=22056)
My calculations suggest it cost me around $60 a month in the cold months. In that thread, I suggest getting a thermally controlled outlet that will control a switch only electric heater so that it turns on at 35* and off at something like 45*.
I did order the outlet, but have not hooked it up yet. The electric heater that we have been using is thermostatically controlled and will not work with that outlet. However, we have a unit that is a simple switch (on/off) and it should work fine.
Jim
Quote from: TedsBUSted on November 17, 2011, 04:18:02 AM
...
My point is that a fan motor converts energy to actual work and not simply to heat. ...
In summary, my minor, simple, concise point is that the portion of an electric unit heater's current draw which feeds the fan motor is NOT converted to heat energy, but to work, in the form of moving air.
Yes, this is correct ...
Quote
... Yes, someday when the universe implodes maybe the fan's work will become heat again....
... but this is the part that's wrong.
It's not "someday" a long time from now -- it is almost immediate. Where do you think the joules of work are going?
Forget about moving air for a moment, and let's instead consider the work done to push a heavy box along the shop floor. Whether you use an electric motor or you push it yourself, a certain amount of "work" is done to move the box. The First Law says that that work can't just disappear, but when you stop pushing the box, where did it go? The answer is every bit of it, 100%, was converted to heat by the friction of the box against the floor.
This is, in fact, where most work goes. Now if, instead of moving it along the floor, you lifted the box onto a table, most of that work would have been converted to "potential energy," which is released when the box again moves from the table to the floor. You could connect the box to a pulley and a generator and get some of the work back in the form of electricity. But moving laterally along the floor, 100% becomes heat from friction.
Now back to the fan: 100% of the energy imparted to the air by the fan, which is work, becomes heat through friction. Not "someday," but by the time the air stops moving. What stops the air from moving is damping, and damping is friction, plain and simple.
Same is true for the toy train -- yes, the motor performs work, to move the train. But when you turn off the power, the train stops almost immediately, and 100% of the work used to move the train immediately becomes heat.
So, ultimately, having some of the electricity go to a motor rather than a resistive load causes, at best, a slight delay -- on the order of seconds, or maybe at most a minute --in heating the interior, as the electricity is first converted to work, and then the work is converted back to heat. But in a steady-state, that delay is irrelevant. There is no getting around it -- in a closed system like the inside of a coach (or a house, or a computer room), absolutely every watt-hour that goes in becomes heat, unless it first comes out in some other form as I discussed originally.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Just to throw another thought out here on these infrared heaters. I was foolish enough to buy one several years ago. I agree that most of the claims the manufactures made are lies. However, I loved sitting in front of the heater every morning before I got fully dressed and let the infrared heat absorb in my back and my knees. It is my opinion that there might be something therapeutic about the infrared heat. As for any other claims of these heaters they are bogus and certainly not worth 3-4 hundred dollars or so.
I happen to have a 1025 sq ft house and there is no way this heater could heat my house but the heat it did put out felt good. Could it heat a bus? Very likely. However, not any better than any other $1500 watt heater... but the heat may feel better.
It's never too late to pick nits on and on and on!
I've used Presto parabolic dish infared heaters for years. They work great heating the guy in the chair, though the overtemp sensor always goes bad after a couple of years.
OBTW: Sean's right.
There's a lot of abstract theory that just doesn't come into play in the real world. I tried to underscore that from my entrance into this discussion. For example, when that box is being pushed around the shop floor, if 100% of the work is being converted to heat at the friction point with the floor, then what's happening with the energy being used to displace air? Never mind, I don't want to know, but I think it underscores my point.
Back to the coach heater. IF hypothetically 100% of fan energy that is dispersed in air handling and parasitic heat loss could be immediately collected and added as heat input to a coach, it would amount to something close to a whopping additional 3/100ths of the heater's output. Basically that'd be about the same amount of resistive heating that goes on within a turn signal flasher.
I realize that some probably don't want to believe that a fan's mechanical energy doesn't quickly revert to added heat within a coach. Just as it's tough to believe without seeing that a "choked" fan draws less current. Therefore I propose that we conduct a real experiment, very relevant to bus heating. So some cold night, in my coach, give me a blanket and a measly 1500 Watts and a heating element. No fan at all, I'll just rely on convection in still air. In your coach, use whatever size fan you desire. Let the fan hurl and ricochet air molecules throughout the coach until they're in a heated frenzy. Shoot, go ahead and add another fan or two. In fact, go ahead and use as many fans and Watts as practical, and I'll even throw in the heat from the fan motors, which we haven't factored yet.
We can then continue this discussion in earnest the morning after the experiment. Meanwhile we can consider this to be just a friendly splitting of hypothetical hairs.
Ted
Quote from: TedsBUSted on November 18, 2011, 05:23:12 AM
There's a lot of abstract theory that just doesn't come into play in the real world.
Ted, the First Law of Thermodynamics is neither abstract, nor a theory. And it comes into play in the real world every single day -- this is precisely how engineers such as myself calculate things like how much air conditioning is required to cool a room.
Quote
I tried to underscore that from my entrance into this discussion. For example, when that box is being pushed around the shop floor, if 100% of the work is being converted to heat at the friction point with the floor, then what's happening with the energy being used to displace air?
It's negligible, and I omitted it from the example, but if you insist, it also becomes HEAT because moving air against itself or the walls is no different from moving cardboard against the floor -- friction is what damps the air and that causes it to heat up.
Quote
Back to the coach heater. IF hypothetically 100% of fan energy that is dispersed in air handling and parasitic heat loss could be immediately collected and added as heat input to a coach, it would amount to something close to a whopping additional 3/100ths of the heater's output. Basically that'd be about the same amount of resistive heating that goes on within a turn signal flasher.
Well, true, but you were the one who brought it up in the first place, insisting that the work done by the fan became something other than heat, which is incorrect. The discussion then grew to incorporate the concept that lots of things in a coach that consume electricity turn it into heat, not just heaters.
Quote
I realize that some probably don't want to believe that a fan's mechanical energy doesn't quickly revert to added heat within a coach.
Some don't want to believe? You mean, just because you say it, we should believe it, even though it's wrong? Ted, this is basic, freshman-year physics. The First Law often runs counter to people's intuition, which is why it is drummed into the brains of scientists and engineers early on. You are continuing to argue from an intuitive position -- your sense is that a fan consuming 100 watts of power makes less heat than a light bulb consuming 100 watts of power. But unless the fan is blowing on a windmill, it does exactly that -- 100 watts of electricity becomes 100 watts of heat, whether it's a fan, a lamp, or a toy train running in circles.
Quote
... Therefore I propose that we conduct a real experiment, very relevant to bus heating. So some cold night, in my coach, give me a blanket and a measly 1500 Watts and a heating element. No fan at all, I'll just rely on convection in still air. In your coach, use whatever size fan you desire. Let the fan hurl and ricochet air molecules throughout the coach until they're in a heated frenzy. Shoot, go ahead and add another fan or two. In fact, go ahead and use as many fans and Watts as practical, and I'll even throw in the heat from the fan motors, which we haven't factored yet.
OK, but I want the bus insulated by a perfect vacuum. Look, we all know these will produce two different results -- but NOT because the fan generates less heat. As I said way up at the beginning, it is because the fan will move whatever heat is already in the coach past leaky or poorly insulated windows and other heat sinks. IOTW, the same heat will be generated, but one of these methods will end up moving more of it from inside the bus to outside -- again, I said this in my very first post. That has nothing to do with your assertion that "work" does not become heat.
Quote
... Meanwhile we can consider this to be just a friendly splitting of hypothetical hairs.
Well, again, it's not hypothetical, and I want to make sure that the folks reading this discussion have the right answer. I'd like for you, too, to come away from this with a better understanding of thermodynamics, but that requires an open mind.
The "thought experiments" that I have described, such as the "black box" concept, or the example of the box on the floor, are standard pedagogical constructs used to teach these concepts. The idea is to look at the very limited, non-real-world circumstance and develop an understanding of where the energy is going, since the First Law says it can not disappear, only change form. Then take that understanding and apply it to larger, more complex scenarios in the real world. Students who look at the thought experiments and disbelieve them because they are somehow "unrealistic" or can not apply the concepts to the broader world are generally not cut out for science.
In the black box experiment we saw that, inside a perfectly insulated box, a fan drawing a certain amount of energy can not be distinguished from a lamp drawing the same energy -- each will heat the box exactly the same amount. Now, if you don't believe this part, you can do the actual experiment and see that it is true.
The box itself is merely a learning construct -- when you take the box away, the energy involved still does the same thing it did when the box was there -- it's just a lot harder to measure.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Something that occurred to me while reading this thread (that I'm sure was obvious to many of you - I apologize for being slow)... is that the movement to LED-based interior lighting will result in a lower A/C load, and a higher heating load. Maybe the delta is nominal, but for me, it's an interesting thing to think about.
While lots of people think about the heating/cooling load impact of stoves (as well as microwaves and ovens), the impacts aren't limited to these items. In fact, all of the decisions we make about energy consumers of any kind (including lighting, toilet fans, etc.) have an impact on the heating and cooling loads.
-jbn
Quote from: jbnewman on November 18, 2011, 08:45:30 AM
Something that occurred to me while reading this thread (that I'm sure was obvious to many of you - I apologize for being slow)... is that the movement to LED-based interior lighting will result in a lower A/C load, and a higher heating load. Maybe the delta is nominal, but for me, it's an interesting thing to think about.
While lots of people think about the heating/cooling load impact of stoves (as well as microwaves and ovens), the impacts aren't limited to these items. In fact, all of the decisions we make about energy consumers of any kind (including lighting, toilet fans, etc.) have an impact on the heating and cooling loads.
Yes, which is why I thought it was important to clarify the concepts. Good to see that someone is getting something out of it -- otherwise it's just so much arguing for no reason.
FWIW, heating a bus is much easier and less expensive, generally, than cooling it, which is one reason why LED lighting is such a boon, even if you are not running strictly from batteries. Even fluorescent lighting adds less heat to the coach for a given amount of light than incandescents.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Question If a fan draws less Power when air is blocked off. Would the dampers and shutters on the MCI cooling system draw less hp when blocked off thus increasing my MPG.
Rick 74Mci
To add just a tidbit to the discussion.....
If you agree that an impeller type pump moving water is very similar to a fan moving air then I had an experience that might be of interest.
I had a self priming irrigation pump that lost it's intake. It ran for hours just churning the water in the pump housing until it boiled and melted the PVC pipes connected to it. It wasn't the motor that overheated but the pump just from the friction of the impeller in the water.
So, I think that a fan in an enclosed box would continue to get hotter and hotter, just from the friction of the blades against the air, not even counting the heat from the motor.
I have a better understanding of the dynamics of heat in a coach due to this thread. Please continue post like this.
Big John
arguing for no reason
I like to think of it as informational banter... :)
Um. So in baby terms what's being discussed is:
Any electric device that uses 100 watts, will produce 100 watts of heat regardless of device?
Thanks in advance.
Quote from: Scott Bennett on November 18, 2011, 12:10:38 PM
...
Any electric device that uses 100 watts, will produce 100 watts of heat regardless of device?
Not quite. As I described in earlier posts, if the energy has someplace else to go, it does not become heat, or at least not right away.
An example would be a battery charger. While chargers do produce plenty of heat, which, BTW, is a waste byproduct of the charging process, and why no charger is 100% efficient, at least some of the energy going into them ends up being stored in a battery.
If you measure the amount of energy that ends up in the battery, and the amount of energy consumed by the charger, the difference between these two numbers is the amount of energy that must be dissipated as heat (either in the charger itself, or the heat given off by the battery as it charges).
Likewise, if you have a pump which pumps a fluid from a low place (lower potential energy) to a higher place (higher potential energy), the difference in energy potential of the fluid does not become heat; you can think of this as "gravitationally stored energy." BTW, such systems exist, on a very large scale; where large electric pumps take river water and pump it uphill to a reservoir, then, later, the water is let out through those same pumps, now operating in reverse as electric generators. One such example is the San Luis Reservoir near Los Banos, CA, which stores water from the Central Valley Project.
An electric fan in a closed box (such as a bus) will dissipate all its energy as heat, because the air that it is moving will heat up from friction, with no place else for the energy to go. But if you put a windmill in front of that fan, and connected the blades to a generator, and then ran the output someplace else, then all the energy produced by the windmill will not end up as heat -- at least not until it gets to its point of use. But again, that process would be very inefficient, and frankly, most of the fan's work would still end up as heat.
On a bus, for all intents and purposes, you can assume that every watt that goes in becomes heat, with only a few exceptions, which I listed in my very first post.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
So update on the infared heat.........
Here in iowa where it has been droppiiing into the teens at night and about 35the during the day...... and my fish has all the original windows and really no added insulation to speak of........
the heaters keep it about 55......not "warm" but better then 3
13h degrees!
I think with some insulation added and sealing her up a bit that it really should be quite good....I will repost after we make those upgrades.....
Thank you again for everyone's knowledge and help!
Noah and family