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Company Develops Microwave-powered Water Heater
dponce80 writes "Pulsar Advanced Technologies has announced that, starting next week, they will launch the MK4, a microwave-powered on-demand water heater. Why is this cool? Well, until now, you had two options: electric heaters that keep a large amount of water hot at all times, or natural gas heaters that heat up water on-demand. The first is very costly and wasteful, and the second is not available to everyone, especially those in rural areas. You can't heat water up quickly enough with conventional resistance-based electric elements, as it would require huge amount of electricity. Not so with microwaves. The Vulcanus MK4 can heat water from 35 degrees Fahrenheit to 140 degrees Fahrenheit in seconds and can source multiple applications at once: showers, dishwasher, sink usages and more. The Globe and Mail has an article with a little more information."
Another fine product from Wayne Enterprises Military Division...
Now I can have a long hot shower in 30 seconds.
-- I ignore anonymous replies to my comments and postings.
Microwaves kill various germs too, don't they? They should market this as both a water heater and a sanitizer.
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Will this power my Delorean?
I'M a conventional resistance-based electric element, you insensitive clod!
BTW, the article 'summary' contains wholesale copy/pasting from the article linked to, which itself is just a press release that offers no additional data.
Has anyone considered putting together a submission etiquette guide for the editors to use when greenlighting stuff? Something that includes a dupe check, a Ron P. filter, and perhaps a 'marketfluff' detector? Such a device would come in handy for things like this, "articles" that make Popular Science read like the freakin' Encyclopedia Brittanica in comparison.
The microwave could be useful with really hard water though. It might not get deposits as much, depending on how it was done.
From a company with "Pulsar" in its name, I would have expected them to use gamma radiation.
sigfault. core dumped.
We've been using microwaves to heat food for years now. How come no one came up with this idea before? Is there a technical limitation that has been overcome?
cat
You can't heat water up quickly enough with conventional resistance-based electric elements, as it would require huge amount of electricity. Not so with microwaves.
So, microwaves need less energy to heat up water the same amount? Strange... The heating with resistance-based methods is already close to 100%; the loss occurs with storage of the warm water. But you do need the same amount of energy (and thus electricity) to heat up water, whether you do it using resistance-based methods, or microwaves.
so we have a mature technology being applied to a new sector. this has the opportunity to save a lot of us money and also the effort required to keep a pilot going. the question is, will it be offered at a fair price?
When I tell an object to delete this, am I killing it or telling it to kill me?
You can't heat water up quickly enough with conventional resistance-based electric elements, as it would require huge amount of electricity
Were I lived (the real world) many people had on-demand heating with conventional gear in the seventies, and still do.
"When I first heard Daydream Nation it quite frankly scared the living shit out of me." -- Matthew Stearns
I'm fairly certain that SETS' tankless water heaters do in fact use a conventional electric element to provide heated water on demand. Check out their site for more information, but I've seriously been considering replacing my old water heater at home with one of their products.
Which isn't to say that on demand microwaved water isn't spiffy keen also!
The article, not the idea. It's two paragraphs, and the company that's developing this thing doesn't even have a website up, other than a big shiny logo.
This is the first time I've bitched about the editors here, but in this case, I think it's deserved. I'd honestly prefer a dupe or something a month old than a story with no substance at all.
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl
Well, until now, you had two options: electric heaters that keep a large amount of water hot at all times, or natural gas heaters that heat up water on-demand.
WRONG!!
it should be
Well, until now, you had two options: natural gas heaters that keep a large amount of water hot at all times, or electric heaters that heat up water on-demand.
Why in the world is a new product developed by anybody other than Google?
My mistake. I never thought I'd see Farenheit used on a technical message board, so I automatically thought 140 degrees was superheated water.
That'll learn me to pay attention.
Jesus saved me from my past. He can save you as well.
This device was first seen in the movie "Batman Begins"
Grundgesetz * 23. Mai 1949 - 30. November 2007 - http://www.vorratsdatenspeicherung.de/
Bummer. If you were thinking of having your own particle accelerator in Alaska, pick another city.
Here in Australia, many people use off-peak gas hot water. A gas burner runs at times of lower gas demand (when e.g. gas cooking for dinner is not happening) and a tank holds the hot water. Is this practice uncommon in the US or is the submitter just an idiot? (Note: both options may be valid)
Sick of WoW? Try the thinking man's MMORPG: EVE Online
Bzzzt. Thanks for playing.
-Ryan C.
We all expect it being "hot!"
Maybe Computers will never be as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]
Any time I am feeling cold, I just turn on my Pentium 4.
We don't have natural gas available where I live, but we still have hot water on demand. It's called 'oil heat', and as far as I know is available most anywhere in the US. Granted, oil has its downsides, but so does natural gas. At least your house won't blow up if you have an oil leak
I am placing you under arrest for violating the Second Law of Thermodynamics. You do not have to say anything. Anything you do say will be written down and sold to those guys who spam Usenet with ads for "friction free" bicycle lights.
When I am king, you will be first against the wall.
I want one! Around here, when someone wants to take a shower it'll be twenty minutes before anyone else can without getting frozen like a popsickle. ...and don't dare think about two people taking a shower at the same time, unless you're going for a thirty second rinse. We have three showers, but the hot water heater just doesn't cut it. It's electric by the way. Maybe I should skip my new computer upgrade to find a new water heater......... nah!
I was thinking the exact same thing. Microwave technology has been in our household for what has to be more than 20 years now. The potential of using it for other things than heating food should be in plain view.
If everyone swaps their conventional heater with a powersaving microwave heater though, the electricity companies will see a lot less demand for electricity since they obviously consume less power.
Maybe there's some fertile ground for a conspiracy theory here. Gentlemen - fetch your tinfoil hats.
OK, I'll buy the first part, you can't heat water quickly enough for on-demand use such as a shower, as it would require unreasonably high current, even if the electric water heater was 100% efficent. I've done the math on that. The thing is, that holds true for any way you try to heat water by electricity, including microwave, not just "resistance-based" heating. Assume 100% efficency; do the math. You don't get more than 100% efficency just because you use microwaves. You'll see that you can't heat water fast enough to maintain a flow rate in a shower. So unless you plan to have a tank of water at each point where you use hot water and heat it a few munutes before you need it, this just doesn't pass the math. And, of course, heating tanks of water all around the house isn't pratical either; if you heat a large tank and then just wash your hair you waste a lot of hot water that will cool down before it is needed; if the tank is not large enough then the flow turns cold long before the shower is over.
Yea, it would be really neat, and I'm sure that some people who really want this will mode me down because they don't like what I'm saying. But the math doesn't work. And I did read the links. Zilch on the official website. The linked article shows no power usage math and get as technical as saying the thing is the size of a "stereo speaker". I have had a lot of stereo equipment over the years but I have absolutely no idea how to translate that unit of measurement.
I'm an American. I love this country and the freedoms that we used to have.
The powder will be poured into the water system and then this device will be used to heat the streets of the city, allowing everyone to inhale said hallucinogenic powder for teh win.
We have secretly replaced these Slashdot mods' sense of humor with a rusty nail. Let's see if they notice!!
Since Joule we know that energy (e.g. electrical) and heat are equivalent. It doesn't matter how you convert it: bulb,resistor, microwaves...
Aerogel is an incredible substance made 99.8% air. It's a super insulator (my words). Loosely speaking,it's like Jello in a solid form with the water replaced with air.
Hot water on demand would require a smaller amount of surface area for the chamber, thus less aerogel needed..a cost improvement. Google aerogel--I see some recent articles in the google 'News' tab as well.
Nasa/JPL offers a description here:
http://stardust.jpl.nasa.gov/tech/aerogel.html
Stop invalid scientific research. Ask your local scientists to feed their lab rats with a phytoestrogen-free chow.
there are electrical tankless water heaters
I prefer the "u" in honour as it seems to be missing these days.
no longer will my 30 minute showers in the morning mean cold water for the rest of the family.
...and the second is not available to everyone
unless it costs less than a couple hundred bucks, it won't be available to anyone.
My Dad works at a place that sells these in Canada, and has been selling them for a while (not sure how long exactly, but well over a year). Not the microwave variety like the story talks about, but the electric variety like SETS. He says they work quite well, but it does take people some time to "accept" them.
There are a decent amount of this variety out now, it appears. And if they're being sold at Home Depot to your average Joe, then I'd say that at least the electric version of this technology is mature enough.
I would buy one if my water heater wasn't working so darn well right now (I hope I didn't just sentence my water heater to a premature death).
Todd
In a lot of countries (like Germany where I live) on demand electric waterheaters (called continous flow heaters) are very common, especially in apartments buildings where there is no central water heating. They work well, and from the (very old) model I have in my apartment you get hot water in less than 30 seconds. Modern units can be set to a fixed water temperature and hold this even with changes in the amount of water flowing.
Also, as another poster pointed out already, those units do not use up any more energy than other technologies would to heat the same amount of water.
This reeks of some marketing crap. There are plenty of on-demand electric heaters with very high flow rates. Yes they require massive amounts of electricity, but I don't know that a microwave based unit would require that much less. Since they don't quote any power rates or even seem to acknowledge their competition's existing and time tested products it leads me to believe that this is a bunch of marketing hoopla to drum up business for their products.
If you want to heat 2-3 gallons of water per minute from say 50F to 130F using electricity you need a SERIOUS load. These on demand electric heaters often require 100 or 200 amp breakers BY THEMSELVES which most often means that in order to use them you have to upgrade your home's entire main breaker panel AND you may have to pay the utility company to give you this type of service as they typically do not have not installed equipment and lines capable of providing this amount of power to a home.
I do se a bit of an advantage in that it's possible that an on demand microwave heater, although ideally less efficient than ceramic/resistance based heaters, could provide both a size and a maintenance advantage over a conventional heater.
On-demand water heaters have been around a very long time and it seems in the last year or two they have come back in vogue again. They work OK. They can save you money. But most people can also save money with a much less substantial outlay by upgrading their old water heater to a newer model that is better insulated and more thermal efficient. There are even dual gas/electric heaters that let you change fuels to suit whatever is currently cheaper. In many areas such as the one I live in electricity is much less expensive in the winter than in the summer and gas is the opposite.
Although the actual temperature needed for bath or shower water is only around 40-45C, running at that temperature with a conventional system is dangerous because it allows the growth of bacteria in the system, including legionella. Using microwaves will disrupt all the bacteria and mean that low temperature operation is possible, exactly like using a suspended UV lamp in a conventional cold water recirculating system. If the water has only to be heated to around 45C rather than the usual 60, there will be less energy loss and the volume of water that can be heated will be greater.
However, at the end of the day unless you have a renewables (wind,solar,water) generator, using electricity to heat water is a Bad Thing. By the time it reaches you, the generation efficiency is down to around 30-35% allowing for losses, which means it will always suck badly compared to gas, oil or solid fuel water heating. In terms of sheer efficiency nothing beats a thermo syphonic system running on anthracite - no electricity used, and no water vapor created by combustion to remove latent heat up the stack in steam. A condensing boiler is nearly as good but rarely installed properly. I personally feel the long term energy saving solution lies in more efficient tank heat exchangers with better insulation, and certainly there have been a lot of developments in recent years.
Pining for the fjords
NEWS FLASH: Heating water requires huge amounts of _power_ (since it has the highest specific heat of any liquid), regardless of the method used to do the actual heating.
Even if you use microwaves, you'll still need at least 4.19 J/(kg * K).
On demand electrical hot water heaters (known as tankless) have been around awhile.
Another interesting portable product which I use, and with which I am very happy, is the Coleman Hot Water on Demand; this one uses propane and is designed for camping.
Love many, trust a few, do harm to none.
It seems to me that it all boils down (no pun intended) to the different efficiencies between conventional electric water heaters and microwave water heaters.
If the efficiency of a resistor-based electric water heater is x and the efficiency of a microwave-based electric water heater is y, and y > x, then my math says that a microwave water heater is more cost-effective from an electricity point of view and can heat water faster. Neither of them have to be 100%, and in fact, that's impossible. All that matters is that one is better than the other.
One thing I know for sure is that there are existing on-demand water heaters, so I assume the press release means that the microwave technology is cheaper or otherwise better.
I have to admit that I lied about one thing, though: that pun was actually intended. Sorry about that, I promise I won't lie again in this post.
So ... the idea of having a power plant heat up water as well and sending it out to households as a sort of ... "central heating" ... and then having a heat exchanger heat the water locally wouldn't work? Say, send out really really hot water and use something like ... maybe a 2.5 liter exchanger?
... couldn't possibly work. I know we never see stuff like that in Denmark. </irony>
Nah
We do not live in the 21st century. We live in the 20 second century.
this is seriously cool, but not a scientific breakthrough.
i learnt that water was fine in the microwave years ago the first time i had a cup of coffee go cold because i got engrossed in what i was doing.
wicked product though, send me one and i'll test it for you
Gas on Off peak? Not the I have ever heard of. Electricity on off-peak. By-the by, storage heaters I believe are relatively efficient, the insulation of them is effective so they only lose some small amount of heat in 24 hours (which is why off peak works, because you only heat the water once a day and it stays hot for 24 hours) By-the-by-2 a calorie of energy is going to heat a gram of water 1 degree C whether it is inserted into the water by microwave or by elemnet. A 2 kw electic kettle will heat the same amount of water twice as much as a 1000 watt microwave. 2 kw (or 478 calories/sec) will heat .478 liters of water by 1 degree C per second, so in-line if your cold water needs heating by 30 degrees C to shower you get a flow of less than 1 liter per minute from a 2 kw element or microwave. At that flowrate I would take a book, or a friend because you will be in there a while.
The memories of a man in his old age are the deeds of a man in his prime - Floyd, Pink
The submitter, whose email address is under the domain name ohgizmo.com, lives at:
The company's contact:
Mount Royal is a borough of Montreal.
Now isn't that just a wild coincidence that the story submitter lives about 15 minutes away from Mr. Ponce? I confirmed Mr. Kottos's address via a Google search on his name.
PS: Here's another wild coincidence.
Please help metamoderate.
The Vulcanus MK4
Heh, heh. You said anus.
Slashdot editors seem to be taking money to run public relations press releases as stories. Here's a quote from the Slashdot story: "You can't heat water up quickly enough with conventional resistance-based electric elements, as it would require huge amount of electricity." ?????
... requires complex nutritional requirements such as high cysteine levels and low sodium levels to grow. "
The energy to heat water is fixed. Normal electric heaters, called "resistance-based electric elements" in this story, use 100% of the energy to make heat. They are 100% efficient.
A microwave device would waste energy in making microwaves. That wasted energy would be heat, but it might be difficult to put that heat into the water. And why spend more to get another kind of 100% efficiency?
In Brazil and New Zealand, for example, shower heaters are often 220 Volts at 25 Amps. They heat cold water instantly to shower temperature. The heating elements cost less than $10 local equivalent.
Disgusting nonsense quote from the referenced article: "The technology is designed to eliminate the deadly Legionella Pneumophila, since water will not stagnate, as it does with conventional hot water heaters."
Here is accurate information: "Legionella
You don't get Legionaire's disease from water heaters! The high heat in water heaters kills bacteria. The linked article about Legionella says that it can live in shower heads, but that is at a cool temperature, on the outside.
It's made by Sanyo, and it even has a clock on it...
Athy, athier, athiest.
Well, until now, you had two options: electric heaters that keep a large amount of water hot at all times, or natural gas heaters that heat up water on-demand.
:P ).
My parents have a bathroom with two "water-heaters", working in exactly opposite manner:
1. an electric one that heats up water on demand (but I admit the water's not too hot, which, btw, saves a lot of water cuz nobody wants to take long showers then
2. gas-based one that stores some hot water all the time (it's enough for a 5 minutes-long shower).
That's Cool!
Heating water with a resistance heater is essentially 100% efficient (with proper insulation and construction). Heating speed is limited only by heater/element contact area and available electrical power. Hasn't anyone ever seen an "insinkerator"? Instant hot water at the sink.
On the other hand, if you are generating microwave energy in a magnetron, the maximum efficiency of power in to microwave power out is no more than 50% or so. The rest of the input electrical power is removed as waste heat by a ventilation fan (for the magnetron), by conduction (for the loses in the high voltage power supply transformeter), etc.
If you don't mind the inefficiency of heating water with electricity (most expensive method by factor of two) and throwing away another 50% of the electrical power as waste hot air, go ahead and pay five times as much for your "microwave" water heater and spend a dollar per shower instead of $0.25.
I recently researched buying an electric on-demand water heater for my own home. Such heaters consume around 10-20kW and can demand 100 amps of current, they are however very efficient (as someone else noted) and so there is little waste to squeeze out of the system (a few percent at most I expect). Using microwave generating magnetrons is likely to be less efficient imo, so it is very hard to see how this company can live up to its claims. Whether by microwave or resistive heating, the same amount of energy needs to get into the water, it is not at all like a food stove where microwave ovens are genuinely more efficient (less heat loss and only the item being cooked is heated, not the stove walls too). The reason I didn't purchase an on-demand heater is that the electric service in my house would have to be upgraded, at a cost of around $3000. A new water tank, with heater, cost $700. The microwave heater would also have this cost issue. A better way to save power (nationally) would be to have dual-band power pricing (as is done in the UK) where power used in off peak hours costs less than in peak hours -- in this case a storage tank is potentially MORE efficient than on-demand since it can shift demand to off-peak hours when there is unused capacity. In any event, I doubt that a properly insulated water tank actually loses much heat, the main advantage of on-demand is that there is a never-ending supply of hot water. Andy
On one hand, it may not be much more useful than existing technology. On the other hand... microwaves! I don't know about the rest of you but when it comes to making my home absurdly futuristic, electric or gas heaters just don't cut it.
No kidding!!! What do you say at this point?
This isn't appropriate for Slashdot! Everybody knows geeks don't shower!!!
Check out my foes list to see who is so retarded that they can't use the signature line!!!
That should be Mr. Kottos. Mr. Ponce is the story submitter. Whoops!
Please help metamoderate.
does work really well, I am finding, now that I live in Moscow. :)
Patent: from Latin patere, to be open
.. it's the opposite actually.
Electric water heaters are those with water tanks (There's one at my place, it takes quite some space in my already small kitchen). They hold a limited water volume and keep it hot at all time. Gas heaters don't have reservoirs. They can heat water way faster than electric ones, therefore they do it on demand. (I wish i had one)
Anything you do can get you slashdotted, including nothing.
I've used on-demand electric hot water systems in both the UK and Japan.
I'll grant they're a bit like being piddled on by a cat.
'There is a Light that never goes out.'
Many heaters are slow, and are intended to heat up a large tank over many hours. This does not mean that all resistance-based heaters are slow and must have tanks. (indeed, fast tankless ones are available)
People often consider microwave ovens to be fast, mainly because food is heated deep inside instead of needing to first heat the outside. By association, microwaves must have some special magical property.
In reality, this new microwave water heater is going to be less efficient than normal. It will dissapate heat to cool the tube; this heat is unlikely to get into the water. A resistance-based water heater is fully immersed, and thus doesn't waste heat in this way.
So, how much water does this thing heat "In seconds"?
No smoking sigs indoors.
Not every coil-based system involves a big tank of hot water.
If you want fast heating, use low-mass coils with lots of surface area. Put then at the shower, eliminating the tank and the hot water plumbing.
If the microwave tube gets hot and is not fully submerged, it will be less efficient than a nice coil system. You could get a very good coil system for less money.
Welll... scientists found that after eating stuff that was heated in a microwave caused poeple to have the same blood values as someone who is short of getting cancer.
;P
I would not want such blood values every time i eat or dring somethign hot...
No thanks! I'll wait 'till global warming solves it for everyone...
(If you need it *now*, try aerogel!)
Any sufficiently advanced intelligence is indistinguishable from stupidity.
First, have the tank bring the temperature from 30 F (-1 C) to 68 F (20 C). Pipe that around the house. Use on-demand heaters for hot water.
B*gger this for showers and kitchens, BUT...
for years I have been dreaming of something like this for tea (I mean the real stuff: 1 big chipped mug, 1 english teabag, milk, 2 sugars, ta luv).
Instead of waiting 60-180 seconds for an electric kettle to boil (where you always make too much water), have something microwave-driven which will produce exactly 1 mug of boiling hot water in 2 seconds through microwave heating... heaven!
Additionally, I'm sure you could hack something like that into a wicked steam-driven repeater potato gun...
Not confused enough? http://translate.google.com/translate?u=www.slashdot.jp&hl=en&ie=UTF8&sl=ja&tl=en
"used by most households throughout Central and South America"
:-)
Uh huh. I'm sure it also works in Hawaii, southern California, and southern Florida.
It's not going to work when the incoming water is so cold that it will freeze if you let it stop moving. Northerners leave the faucets dripping at night so that the pipes don't freeze solid.
Believe me, the math just doesn't work.
Was that on the real planet earth people have had electric showers for decades.
Deleted
I have considered a few times the mechanisms involved in tapping hot water.
My water heater tank is a fair distance away from the kitchen sink - meaning, the wait from turning on the tap to the water getting hot represents quite a length of piping being filled with hot water. I'm just tapping off the very end of it, while possibly ten times more hot water remains in the pipes. Should I want to wash my hands again five minutes later, the water in the piping will have gotten cold and needs to be repiped.
Surely there could be significant energy savings if you had a very local point of heating (integrated in the sink) instead? Someone who could calculate the energy loss for x meters of tubing with y width?
I live in the rural parts of Thailand but, due to having a flowthrough type electrical water heating system enjoy hot water on demand without the risk of any potential radiations leaks. Why do people always re-invesnt the wheel and then fail to mention that better technology already exists.
With a natural gas fired water heater and an oil fired radiating heating system, the thing I'd like to see is a secondary hot water storage system which will heat water in a secondary standby tank while the heating system runs but the water tank remains unused. The oil heater used to heat water for hot water use on demand, but that meant that the oil heater was in use all year. And the quantity of water heated, along with the small holding tank in the oil heater wasn't sufficient for 1 family in this 2 family house. So we bypassed the oil burner for hot water and added a natural gas fired water heater. Ideally, the system I'm thinking of would use the water heating capability of the oil heating system (separate from the steam making capability for the steam radiators) to heat water that is stored in a larger (200 gallon, 250 gallon, larger) tank, and that water is then fed into the cold water intake of what would turn into the primary hot water tank, the original natural gas fired water heater. This would make heat loss from the secondary system irrelevant, as there wouldn't be a system to heat the secondary water due to heat loss, the only time the secondary tank would be heated would be during winter months when the oil heater ran to create steam for the heating system.
So the secondary tank would be heated water from the oil fired steam boiler, but wouldn't be kept at a constant 140+ degrees F., it would just be heated whenever the oil fired steam boiler ran, and the warmed/hot water would then feed the natural gas water heater's cold water intake, which would mean that the natural gas hot water heater would need to burn less natural gas because the water intake would already be warmer than the 40 degree F. that the cold water intake normally is. If the secondary holding tank lost heat from 140+ degrees to 100 degrees (due to the oil fired steam heater not running for several hours), then the water intake at the water heater would be 100 degrees, instead of the 40 degrees it would normally be if the intake came straight from the cold water main instead of the secondary heating system. Then the natural gas fired water heater would only need to heat the water 40 degrees from 100 degrees to 140, instead of heating the water 100 degrees, from 40 to 140 degrees.
This would capture heat for the hot water system that would otherwise go up the chimney. There would need to be some regulation that regulated when to switch from the secondary hot water intake to the primary hot water heater, to allow intake from the cold water main, or the cold water main could simply feed into the secondary holding tank instead of straight into the primary water heater intake. Or a better method could be figured out. This is what we have engineers for, right?
I work for a hardware/plumbing store, and we sell tankless water heaters. They do have the ability to heat up water in-line, but the difference between this and others is, at least with the ones that we have access to, ours can only serve the purpose of heating for a single application at a time. You can put one under the sink to heat that one line, or you can put it by the shower to only heat the shower, while these will be able to furnish heated water to multiple locations simultaneously. So that is a pretty nice advantage.
GentryDigital.com - A Digital Photography Education
Apparently, a similar competing microwave water-heating device is being offered by Electro-Silica: http://www.pmengineer.com/CDA/ArticleInformation/f eatures/BNP__Features__Item/0,2732,96706,00.html
I emailed this company and if you don't have at least 0.5" diameter copper water pipes running through your house the water heater will not work.
Poster above is correct, electricity coil is 100%, while wikiedia has magnetrons at 75% efficiency ref: http://en.wikipedia.org/wiki/Talk:Microwave_oven. Do the math.
Here is the rub, the magnetron must be sparked up to 4000 volts DC folks, with a whopping big capacitor. Many servicement have been killed from a microwave 'kick' .
Mixing water and HVDC electricity - copper pipes, steel sinks+ bathtubs. Nasty! Imagine the situation New Orleans could have had.
Those with a microwave, KNOW cockroaches are drawn to them like magnets, and cockroach urine forms a good conductor - you see where this is leading. Two dissimilar metals and electric current = electrocorrosion = radiation leaks. Nope , you keep it.
Microwave heating may sound cool, but so would a heater powered by a jet engine, or piped from natural geothermic springs. I've seen 100 year old hot water boilers working fine, whereas little used microwave ovens don't go the distance.
How many Tims have repaired their boiler, Vs Tim's replacing a hot 4000 volt blown fuse. Love to see the insurance angle.
what do you mean you can't heat water quickly with resistences ???
my grandmother's home had an on-demand resistence based heater on the kitchen since the 1970's... small electric showers that heat water on-demand are ubiquitous here in brasil, and has been like that since i remember.
i fail to see then what's the big deal about this microwave heater.
What ? Me, worry ?
They invented microwave oven?
My 1200Watt magnetron in my microwave oven can heat a cup of water boiling hot. In 40 Seconds!!!!!
Tell me how can this thing heat steady flowing water to 120C in seconds?
I've been scanning through these replies and I haven't seen ONE mention of district heating. That is, piping hot water from a central power station to the whole city.
Not only is it super efficient, it is reliable and cheap to operate once you get over the initial investment. Also, you can use heat generated by the generation of electricity -so double efficiency.
This is obviously not a system suited for rural or sub-urban living. But why live that inefficiently anyway?
The great thing about it is, during the summer, you can reverse the system and transport COLD water to homes to cool them off.
With all these benefits, I don't see why it isn't in broader use.
Some say he is made with ascii, others that he is eyeballed daily by millions. All we know is, he is known as the Sig
Some of the arguments here as to if you can/cannot do 'on-demand electric water heating' due to the power requirements are probably because people aren't taking into account 110V vs 230V countries.
The wiring in a house on the 110V system might not be able to handle the current but the wiring in a house on the 230V system definitely can.
This statement appears to be somewhat at odds with reality. The use of electricity to heat water on demand (and heat it VERY quickly) for showers is common. Which backward third-world shit-hole are you in that you've not seen them?
Damn, good idea, why didn't anyone think about that before??
You just got troll'd!
They were originally going to call it the HephaestusRectum MK4, but that moniker proved a bit unwieldy, so they settled on Vulcanus instead.
..more cancers!
The problem is interference. 2.45 GHz is smack in the middle of a band designated as a free-for-all, so anyone using it for communications has to accept whatever interference they get. Certifying a microwave to operate in a licensed band would cost far too much for no benefit.
Time is Nature's way of keeping everything from happening at once... the bitch.
- CowboyNeal is a science-illiterate and has no concept of conservation of energy (and should not be editting science stories).
- CowboyNeal is just stupid (ditto).
- CowboyNeal is taking payments to promote fraudulent products (and should be fired).
I can't think of any other possibilities here.Time is Nature's way of keeping everything from happening at once... the bitch.
35 deg F = 2 deg C = 275 K
140 deg F = 60 deg C = 333 K
So, if your source water is at 35, that's almost freezing, in which case heating on demand may not be quite as important as increasing the overall temperature of the cold water in your pipes. Just a thought.
Burns: We're building a casino!
McAllister: Arrr. Give me 5 minutes.
i mean seriously...how long has microwave technology been around? and just how much intense development would be needed to produce this? it's no wonder our place as technology 'king of the hill' is in jeopardy...
It takes just a moment and an action to destroy. It takes some time and thought to create.
Hot water is for women, children and gay men. Real men bathe in cold water.
Is it just me or is that Pulsar Advanced Technologies website the most sketchy corporate webpage you've ever seen?
Its stated in the article that there are two methods.
Method 1 is to heat water and store it and draw it off as needed. In the UK this is usually done with the aid of one massive tank in the roof, to store the cold water for the hot water store. And a second, to store the cold water for the working fluid, which is used to heat the water in the water store. And then of course, there is a third tank, in which the actual hot water itself is stored.
Are you with us so far?
Well, there is a variant on this method, which consists of having a mains fed hot water store. The advantage of this method is that you no longer need tanks in the roof. The disadvantage is that if this tank, which is under pressure, ever blows up, it takes the house with it. A very small chance however.
Method 2 is to heat it on the way through, either by gas fire in a heat exchanger, or by running it over a hot resistive electric heater. In this case you do not have all those hot and cold water stores in your roof space and closets.
British heating engineers have invented a third way. This interesting method has the great merit of being even more more complicated than the multiple tanks in your roof. In this method, you first circulate the working fluid through a tank of hot water, thus heating it up via a heat exchanger. But you do not bathe in this!
No, you draw cold water in a second heat exchanger through that hot water. In this way you have the benefits of both of the first two systems. You have a constant store of hot water in your closet, and two cold water storage tanks in your roof. And, you get to have hot water on demand heated up for you when needed. And as compared to the variant on method 1, you get to have mains pressure hot water, without having a pressurized tank anywhere in the house.
It is very surprising that this system has never been exported.
When travelling in Central America there were electrical heaters in the shower heads in many hotels. They worked very well, but the thought of what would happen if the ground wire was loose made me search for the fuses...
The statement that you cannot do on-demand heating with electricity is wrong. I had a "Vaillant" electrical water heater that had no problem at all doing this for a shower and a kitchen 15 years ago and it was not new then. Of course it requires something a bit more high-tech than dangeling a coil of wire into a water tank, but the problem is solved and has been for some time. Power consumption when no water is flowing is close to zero. This heater consumed 37kW of energy when running, but there is no way around that. Water takes a certain amount of energy to heat it and water heaters are close to 100% efficient, i.e. no matter what technology you use it will consume about this much power to heat flowing water.
Maybe the countries where this is news are a bit backwards?
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
Data:
Water : 4.18 kJ / kg * K
assumed:
flow : 12l/min ( ~standard tap) -> 12kg / min
dT : 35^K ( i.e 10C --> 45C )
gives:
P : 24.3kW continous
Doing the same with Microwaves would probalby
require
26-30kW
G!
MACC
Here in Sweden where I live we have "Fjärrevärme", which roughly translates as "remote heat". Basically there is a central point in a city that has a huge economical furnace (usually run of trash or sewage or burnable recycling). Water is heated from there and then piped around the city in very well insulated pipes. Seems to be a good way to get the economies of scale, and better efficiency. You don't need to worry about maintainining your own heating equipment either.
"Bergvärme" (mountain heat) is also very common here, which is using small geothermal heat differences and a heat exchanger to reduce the cost greatly (by up to 50% in alot of cases) to heat up houses.
I read all 4up posts and i have not seen this point mentionned:
Where I live (Switzerland) we have a double rate for the electricity. We pay less (about 50%) after 8pm and until 7am. I suppose other countries have this too. So I produce all my hot water during that period and store it in a thank.
If you produce your hot water on demand, you will not get the benefit of this lower rate, unless of course you take showers and do the dishes only during that time, which is not very practical, especially if you have kids.
That's big savings. And oh, yes there are some losses from the tank, althoug it's well insulated, but then these losses "leak" into the room where the heater is and I suppose I need less energy to keep that room warm. So altogether this new microwave system "on demand" would end up to be more expensive for me.
my 2 cents
As others have noted, this microwave heater is a really terrible idea, for many reasons:
- Your basic $69.95 resistance heater does the job with 99%+ efficiency.
- A microwave heater is going to be at best 60% efficient.
- A 20KW magnetron is going to cost serious money!
- A 20KW power transformer is $$$ and heavy too!
- Many houses don't have the extra 40% power available to waste.
Silly, counterproductive, expensive, ridiculously bad idea. Scotty would cry.Most people get their hot water heated by their central heating system. The most common types are: (1) a cistern-fed cylinder, with a coil of copper pipe in which water from the boiler is circulated {so the two water streams, from the boiler and to the taps, never mix, and the water in the boiler's heat exchanger is not being continually replaced} -- a three-way valve downstream of the boiler and pump selects whether to heat the radiators, cylinder or both; and (2) a combi boiler, an all-in-one system which uses a plate-to-plate heat exchanger to heat water from the mains as it is used {a flow sensor in the hot water piping triggers the divertor valve and fan/ignition cycle}. In homes without central heating, either cistern-fed cylinders with just an electric immersion heater {3kW}, or gas flow-heaters are used.
The cistern-fed system has the disadvantage that hot water pressure is limited. So showers in the UK are most often heated by an electric flow-heater, usually 7-10kW -- unless you have a gas flow-heater or combi boiler, or the shower is on the ground floor and the piping is mostly 22mm and mostly straight down.
It's a law of nature that it takes 70 watts of power to heat one litre of water one degree hotter per minute. If the water is coming in at 10 degrees and you want to heat it to, say, 40 degrees, then you will need to put in 2.1kW just to get a flow rate of one litre per minute! An 8.4kW shower will give you 4 litres a minute at 30 deg. differential, but it will require a 35 ampere supply.
Je fume. Tu fumes. Nous fûmes!
I'm hearing lots of technical reasons why this thing is a bad idea, however is the efficiency of this process so bad that it is worse than running an electric element 12 hours a day? Or keeping the natural gas fire going half the day to maintain tank temperature as well? It seems that if the magnatron is only running on water demands that overall it WOULD cost less to use this device.
The thing is, that holds true for any way you try to heat water by electricity, including microwave, not just "resistance-based" heating.
No, no, no, you don't understand. Heat from microwaves is *more efficient heat*. It's like the difference between LEDs and incandescent light bulbs. The LEDs output almost all their energy as light, whereas the incandescent bulbs output light, but they also waste a lot of energy output generating heat.
Water heaters are just the opposite. The resistance based ones are basically just big light bulbs. They heat the water, but they also output tremendous amounts of light, which is completely wasted. (You can't see the light because you don't use transparent pipes, do you?)
The microwave water heaters only output heat (and a little bit of interference with your Wifi network). That's why they're more efficient.
I've always liked the pointsource water heaters and, in fact, in the next house we build I'm planning on doing inline ones just as you described. There will also be a cost savings because you're only using half the plumbing. FWIW, quiet a few office buildings use this method as well, since they need rapid-flowing hot water but cannot predict usage - and would need a huge tank for peak times like after lunch, which would be wasted most of the day.
You're special forces then? That's great! I just love your olympics!
This "article" is a press release being marketed as news by the Globe and Mail. Here is my letter to the editor.
Why do they call it a hot water heater and who would want to heat hot water?
-M
when you see the word 'Linux', drink!
Hmm, so the heat capacity of water must be less when using microwaves to heat it.
Sigh...
Nuff sed.
Oh well, what the hell...
Company Develops Microwave-powered Water Heater
You mean, like a microwave?
Sig Appended to the end of comments you post. 120 chars.
You can get propane fired tankless water heaters, it is not necessary to have piped in natural gas. Go to most any rural hardware store to see them.
As for other alternatives, rooftop solar thermal water pre heaters are also very common, relatively cheap,the payback period is more rapid than about any other alternative energy devices on the market.(I used to sell them, they work great and it is quite possible to build your own at home, as opposed to building your own PV panels which is sort of difficult) And being modular, they can be piggybacked and give you all the hot water you might reasonable want. Basically just big tanks in insulated boxes with glass coverings. They work well in a lot of areas. And you can also get external to the home wood furnaces that produce simply huge amounts of hot water for direct use bathing or washing or for heating the home, using a renewable fuel, or fuels actually, some burn not only wood but corn or entire large custom hay bales, etc.
I once built a small hot water demonstrator that used coils of hose inside of a big woodchip pile in a closed loop cycle using thermosiphoning to transfer the heat. Once it initially heated up due to normal composting action, I got a nice constant flow of hot water out of it.
Plummers make a lot of money for not much work. sounds like he's a smart guy.
Some drink at the fountain of knowledge. Others just gargle.
Once it has been out for a year, and all the BS/Hype/Biz Mktg 101 has died down, the facts will become more clear...including ALL the Costs!
Consumer Reports will be the first top notch independent testing labs to report on all the cost comparison points between the units and we will actually see who comes out on top.
A bit more important is the service life and repair costs and what warranty is in effect and who will stand behind the warranty.
As a mechanical engineer, I like new gadgets, but I take a long time before I jump into new household appliances.
Perhaps from an engineers perspective this makes sense. But heat isn't some universal currency passed between materials; it's an expression of energy contained in the degrees of freedom of a given material. So no, the submerged portion of the heating element is not perfectly coupled to the water. It is producing radiation at frequencies that do not have corresponding water modes. If you look at the absorption spectrum of water you will see it is a poor absorber in the frequencies that are maximal for a perfect blackbody, not that any heating element is a perfect blackbody. A better strategy would be to work at efficiently producing those frequencies most absorbed by water, in the microwave region for example. I don't know how well current elements fit the absorption spectrum of water or how efficiently/economically microwaves can be produced. So this new method may in fact suck. But your reasoning is too simplistic and misses critical nuance.
46 & 2
"...[U]ntil now, you had two options: electric heaters that keep a large amount of water hot at all times, or natural gas heaters that heat up water on-demand. The first is very costly and wasteful, and the second is not available to everyone, especially those in rural areas."
This makes utterly no sense. Here in the US, and I assume in a fair number of places, we have oil or natural gas water heaters that are hot all the time, and I believe I've read (in the Whole Earth Catalog) of oil on-demand heaters. In either case, drive around outside the big cities, and you'll see house after house with 550 gal. propane tanks, like the one we had in our immobile home 19 years ago.
"Natural gas not available outside cities"?
mark
I see one thing that people are forgetting. Transferance of energy. In gas amd electric basically your vibrating a piece of metal and that energy transfers to the water, propogating outward. With microwaves one can cause the water molcules to vibrate directly. There is some distance from source effects, but not as extreme. There is also another advantage of this microwave over "vibrating metal" water heaters. Resistance to the sediment effect, which eventually reduces the efficiency and kills all water heaters.
> Well, until now, you had two options: electric heaters
> that keep a large amount of water hot at all times, or
> natural gas heaters that heat up water on-demand.
Um, that's the other way around, chief. NG heaters heat and keep a large amount of hot water, electric heaters heat up water on demand.
I've used on-demand electric hot water in Europe, and it's only really practical in low flow situations. "Showers" should be more accurately called "mild sprinklings". I'd be interested in a combination system that had both a electric on demand heater and a small NG tank heater. The smaller tank would mean a lower ongoing waste due to the hot water just sitting around plus it would be able to keep up with peak demand usage.
Tom
"natural gas heaters that heat up water on-demand... [are] not available to everyone, especially those in rural areas."
That's BS.
People in rural areas use PROPANE rather than natural gas. And our propane powered Takagi tankless water heater does JUST FINE.
Neat!
How long did you keep it running, and if it was long enough to see, how often did you have to replace the compost? Also, how hot did the water get?
-FL
You can't heat water up quickly enough with conventional resistance-based electric elements, as it would require huge amount of electricity.
/. editors use for a brain, huh?
Christ people, what do you think the microwave thingayamajig will use to heat the water? Will it take Free Energy from the Tachyon Field Of The Earth or something? What do you
A resistive electric heater converts the whole electric energy it takes in into heat. No losses at all! You cannot put out the same amount of heat using less electricity, no matter what Rube Goldberg device you concoct to do it.
The frequency of the microwave will affect different molecules in different ways. Water is just one 'tuning'. There are others, and it can cause some atoms to heat up and change their relationships to other atoms in weird ways. When I first started looking at the simple microwave oven with a skeptical eye, I was surprised by what I found. For instance, certain beneficial compounds in milk are destroyed by microwave heating which otherwise remain intact with conventional heating methods. Some even apparently turn toxic.
http://www.geocities.com/newlibertyvillage/earths
There are multiple sources on this, but they take a bit of work to dig up. The overwhelming belief that microwave food is safe is the major stumbling block. I didn't even bother looking until I randomly found an article on it last year.
-FL
In this house, we obey the laws of thermodynamics!
Can you post some links and technical information? I would really like to learn more!
I would like to see some engineering designs and performance measurements and I would like to try building some of the things you have worked on.
Excellent post - unfortunately the story is fraught with errors. Perhaps this the the new slashdot strategy - post absolutely innane "stories" in hope that we readers do all the corrections.
"You can't heat water up quickly enough with conventional resistance-based electric elements, as it would require huge amount of electricity"
Did you even bother to try to validate that claim at all?
http://www.tanklesswaterheater.com/
Titan 120 model is 60Amp 240VAC, 5 gallons per minute whole house tankless electric, using dual SCRs (silicon controlled rectifiers) for heat exchange. $250 on ebay. Many other manufactures out there as well.
There are some interesting arguments behind that to be certain, but the area which stunned me, (and I'm a confirmed skeptic of microwave products), was that microwave ovens can actually damage food in ways which conventional heating does not. I did some reading, and then realized that, once again, I'd fallen prey to letting the general populace think for me. --I'd bought the corporate/government line without batting an eyelash. "Microwave ovens just cause water molecules to vibrate and thus heat up. Perfectly safe." This is a lie, and the research has been done to back it up.
Essentially. . ,
The frequency of the microwave will affect different molecules in different ways. Water is just one 'tuning'. There are others, and it can cause some atoms to heat up and change their relationships to other atoms in weird ways. When I first started looking at the simple microwave oven with a skeptical eye, I was surprised by what I found. Numerous complex compounds found in various foods, enzymes, vitamins, proteins, etc., are destroyed by microwave heating which otherwise remain intact with conventional heating methods. Some even apparently turn toxic.
http://www.geocities.com/newlibertyvillage/earths
http://chetday.com/microwave.html
There are multiple sources on this, but they take a bit of work to dig up. The overwhelming belief that microwave food is safe is the major stumbling block. I didn't even bother looking until I randomly found an article on it last year.
-FL
Sounds like a lot of hype with no real basis in fact.
Given their figures of 35 degrees in, 140 degrees out, lets do a little simply math.
We're raising the temperature of the water by 105 degrees. A gallon of water weights about 8 lbs. So in order to heat just 1 gallon of water takes 8 * 105 = 840 BTUs.
Finally, lets assume that you need the 1 gallon over a 1 minute period.
840 BTU/min = 14770 watts.
Hmm.
14770 watts is equal to 67 amps at 220 volts. Quite a large load.
What can we do with a gallon per minute of hot water? Not much. In fact a typical shower takes about 2.5 to 3 gallons per minute. Guess we need to triple the power consumption.
Now nothing that I've ever heard about Microwave heating implies that they manage to produce more heating than the power being supplied to them. Also considering that I've seen the specs for a tankless electric hot water heater (which just happens to have 3 stages where each stage happens to be supplied by an independent 60 amp breaker). I have to call into question the reason for even adding the complexity and expense of using microwaves for a tankless hot water heater. The simple fact is that there already exist tankless units (both gas and electric). However, gas is far more commonly used simply because of the much higher energy density. However, there are electric tankless unit if you happen to have a high enough capacity service. I really don't see microwaves managing to reduce the numbers in way, shape, or form.
Ummm I've seen electric on demand units too. Oh, and there are gas tank heaters too, not just electric.
---- Booth was a patriot ----
Why would one need to heat hot water?
It's a water heater.
I can confirm, in my little town most houses have Propane (LP) tanks. A lot of houses use it for everything, we just use it for cooking and drying clothes. The propane dryer is a lot faster than an electric dryer, and is cheaper to run. I just prefer gas for cooking.
For hot water, we have a tankless hot water coil in our oil-fired furnace. It probably uses less than 50 gallons of oil for the whole non-heating season and the furnace man tells me the unit will last longer because it doesn't sit idle every summer to get gummed up.
Water: specific heat capacity is 4.2kJ/ degreeK / kg.
So to heat 1kg 1degreeK takes 4.2kJ
1litre of water is 1kg
To heat 100l (approx bathtub) of water up by 50C takes 50*100*4.2kJ = 21MJ (mega-Joules)
So to heat that up in 21 seconds requires one megawatt.
A 200V supply would have to run at 5kA. That's a heck of a lot more than the supply to my heater, which is probably 30A @ 220V. I dont think the electricity company are going to be putting fat cables in yet. And think of the size of the fuse...
Not sure if my numbers are right... its Friday afternoon, my mind is elsewhere..
Baz
Sorry, I'm an order of magnitude off in the above post. Decent microwave ovens are 1000-1500W, not mW.
Same theory applies though, just much higher power levels.
A 20dBi antenna would put out 3000W from a 30W source.
You can't heat water up quickly enough with conventional resistance-based electric elements, as it would require huge amount of electricity. Not so with microwaves
A resistance-based heater system has very very close to 100% efficiency. Except for the loss in the wires to the heater element (this loss is negligable and in any case better wires mean even less loss - this is just not a problem), a resistance-based heater converts *all* energy sent to it into heat. No light, no movement, just heat. This is as ideal as it gets. One joule of electrical energy becomes one joule of heat energy. No loss. Really.
So, eh, the microwave heater can do the same job with less "electricity" ?
It has, what, a rod of plutonium inside?
Come on.
In the US, a 10kW water heater would use exactly the same size wire as an electric stove.
t ml or http://en.wikipedia.org/wiki/Split_phase
Electric water heaters are used in a great many homes in the US and Canada. A typical residential American electic water heater holds between 30 and 50 gallons and is connected to either a 240V 30A or 240V 40A circuit. 120V residential water heaters are extremely rare. A 10kW tankless water heater in the US or Canada would be provided with it's own 240V 50A circuit, the same as a kitchen range would use.
Note that almost all homes in the US and Canada have split phase electrical service with two hot wires and a neutral wire (neutral is usually at earth/ground potential). In the US and Canada most wall outlets are ~117V and most large residential electrical appliances are supplied with ~240V. See http://www.allaboutcircuits.com/vol_2/chpt_10/1.h
"Instant" electric immersion heaters are nearly 100% efficient. The only reason that they are not commonplace is that it takes a lot of amps at 240V to heat water. That falls back to the service entrance rating and the overall system capacity in a typical residence. Microwaves are a difficult and complex way to heat water that could otherwise use an immersion heater. I suggest you google Eemax if you want to see some instant water heaters. They are electric, but raising the temperature of a 3 gallons a minute from line temp to shower temp is going to take about 16 to 20 kW - about 80 amps at 240v (US typ max residential line voltage +/-120V).
;-)
I have two Eemax 9.5kW models under my kitchen sink, in line with my hot water line. The first heats about 1.5g/m from 70F to 135F for kitchen faucet use, the second heats to 195 for (unlimited) instant hot water. As soon as the slug of cold water is out of the pipes, the first unit shuts off. I can start with near boiling water for pasta as fast as I can fill the pot. While each unit is about $225, it means I waste less water (and time) waiting for the hot water to make it to the kitchen. The down side - I had to upgrade the electric in my house (c1962) to have the power to do it. The best part? If the element ever fails, it's less than $40 for a new one. Oh, as as for not using them as my primary HW source, having a tank means having hot water when the power goes out. Since the power is rarely out for longer than it takes me to use 60 gallons of hot water, it provides a nice "cushion," and my sensitive American tushy never has to suffer through a cold shower
As for cost - I get electricity at about 4.5-6c/kWh and - as of last year's natural gas rates - electric resistance heat is about 10% more than gas heating at a 92% AFUE rate for gas (electric is, by definition, 100% efficient, as all the energy ends up as heat). This year, it will be cheaper to heat with electric resistance than gas. Heck, my oil furnace is costing me twice what it would be for electric resistance, which is why I'm going to a heat pump w/ staged booster coils. I get >100% efficiency on the HP, plus 105F+ register temps all the time. It may not be perfectly efficient, but its the lowest cost, always-comfy solution.
Is it just my observation, or are there way too many stupid people in the world?
Rural areas may not have access to natural gas; but, they do have propane. The same burners work with propane if you adjust the burner's air intake or change the gas orifice size.
Microwave heaters are less efficient than a simple resistance coil. The immersed resistance coil will transfer nearly 100% of the energy to the water. A microwave tube and other circuitry will disipate some energy as heat, which will be lost. The microwave in my kitchen uses 1.6kW input power to make 1.1kW of microwave energy, that's only 69% efficiency.
Besides, electric point of use hot water heaters have been available for decades.
If you have gas as your energy source, you can burn the gas, generate electricity, and use the "waste" heat to heat your water. Then you'd have an appliance which used a negative amount of electricity and could claim it was more than 100% efficient ;)
Gee, I guess that using heating oil to heat your house and your domestic hot water doesn't exist. In the Northeast part of the USA, a "tankless" hot water heater is very common. It is an oil fired unit or gas fires, that uses a separate zone for domestic hot water. You can increase teh volume of hot water by having a seprate thermos bottle like tank attached. In the winter your furnace is running to heat the house and your water is warm with no real extra effort. of course in the summer, your furnace must run occasionally, but it is far more efficient than electric anyways.
The specific heat of water is 4.186 J/g/degC. That means it takes 4186 Joules to raise the temperature of 1 litre of water by 1 degree Celsius.
If you have incoming water at 5C, outgoing at 30C, and you use 1 litre every ten seconds, that's 4186*25 Joules per second, or around 10kW. Note that at 220VAC, you'd need some whopping 50A breakers to do this.
I can absolutely guarantee you that if you take a 5 ohm element (which at 220VAC gives you 10kW), put it in a stream of water of 1 litre per 10 seconds, then the water will be 25C hotter coming out than going in once the system has stabilized.
The only difference with using a microwave system is that it won't take as long for the system to stabilize: it'll take several seconds for the heating element to reach its terminal temperature.
We started a war because we were so sure that it was trivial to come by.
=====
Well, until now, you had two options: electric heaters that keep a large amount of water hot at all times, or natural gas heaters that heat up water on-demand.
=====
What about gas heaters that keep a large amount of water hot at all times or electric heaters that heat on demand?
...that conventional storage water heaters are a religion. I have rarely seen so much energy and emotion expended as their adherent do to fight the evil that is tankless water heaters.
I think you ought to research your claims before posting here. Instantaneous electric water heaters have been around for years. My mother uses a SETS instantaneous electric water heater to supply water to her entire home. Other examples of tankless electric units include remote washrooms to save on the piping, etc.
Please note that I didn't claim that electric water heaters were 99.9% efficient, I just claimed that 99.9% of the energy consumed by one would actually end up inside it. Obviously, any water heater that incorporates a buffer tank will have some standby losses. Please also note that some instantaneous water heaters have standby losses due to their use of standing gas pilots (common on older systems).
Most significantly, I urge you to research the minimum flow requirements that all instant units impose. If you have a whole house instantaneous water heater, it may be very beneficial to have a small buffer tank to cover low loads like a single faucet being cracked open enough to cause flow, but not enough to allow the water heater to fire.
What you're also missing is that the energy distribution companies are gearing up to disincentivize instantaneous gas and electric water heaters, whereever they are attached to their networks (i.e. methane and electric, LP is a different animal). That's because many distribution networks (gas or electric) cannot handle huge spikes in demand, and instantaneous water heating units do exactly that, creating predictable spikes in the morning and in the evening. How will they kill instantaneous units? Simple, peak demand metering.
Utilities and their distributors prefer the slow,steady demand that a low-recovery, buffer-tank water heater imposes on their systems. As meters get upgraded (and ours just did), the utility company not only knows how much you consume, but when you consume it. Demand metering is already standard practice in the Commercial arena (with VERY heavy-handed penalities) and it's only a matter of time before the distribution companies will try to impose the same kind of demand-control on the residential side of the business.
He's English.
They use "faggot" as a term for firewood.
Since this is a discussion about energy conversion, he's calling us North Americans faggots, meaning a low-efficiency type of fuel. It's like saying "Ha, your computer runs at 4 megs!"
Either that or he's stuck in a time or country where it's big deal to be gay. I pity his country's education system.
---
ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
...I would much prefer people to consider innovative ways to reduce their energy footprint. One device that I decided to install my my home is a GFX Heat exchanger from GFX Technology. It preheats the water coming into the water heater with the wastewater coming down the drain. Perfect for showers and other water uses where the make-up water is flowing into the home as the waste water is flowing out (i.e. not much help with bath-tubs).
Solar DWH also makes a lot of sense in warmer areas of the country since they have ample insolation and external storage tanks are not as problematic as in the cold North. The Chinese have allegedly figured this out a while ago with 75+% of the worlds solar DHW installation going on in that country (as of 2002, IIRC).
Another great way to improve the efficiency of an AC while harvesting "free" energy is to install a desuperator like the Aquefier from Trevor Martin or AC OEMs. Use it as a pre-heater with an indirect water heater if you already have a regular water heater.
I have no affiliation with any of the manufacturers I have listed, other than being a very happy customer of GFX's.
Kinda obvious, I suppose, but the submitter made it sound like he was the authority on the subject. There are also natural gas water heaters that work just like the electric ones: keeping a tank of water hot all the time. These are very common in the U.S. Gas is not synonymous with "on demand."
"The thing I worked on I am the most proud of is, I was one of the first guys to have a working protype of what is now called "the mountain bike". I won't claim I was the first, but I will claim one of the firsts and it was developed without me even knowing about anyone elses efforts along those lines. It worked great! Man did I think it was cool, able to get way back in the woods where the dirt bikers went easily. I never commercialised it, but I know that one large manufacturer saw my working bike and very soon thereafter had one on the market. Very coincidental...."
And we thank you for not taking out any patents on it.
Well, I can see that microwaves will act on a volume of water, as compared to surface contact with a heating coil. Actually, what if you had a long length of pipe and had the magnetron positioned at one end, shooting upstream as the water moved past it? Theoretically, those microwaves could heat the water travelling down the entire length of the pipe span. Would this be more efficient than a helicon-style microwave coil? It would allow for more duration of microwave-on-water contact, don't you think?
There are various solar ovens you can purchase or build. One interesting one I saw was built into the south wall of the kitchen. Basically a large insulated box that had glass on the southside and the oven door on the kitchen side. It was only good for one quick cook from around 11 am to 1 pm, but still enough to toast a chicken or whatnot. The stand alone ones work well ( I have a commercial model you just set oputside on the picnic table or whatever), you just have to go turn them to face the sun occassionaly, but that could be somewhat easily automated with some photocells and a small turntable, or just a mechanical timer and some good maths for that matter if you wanted to. a lot of times I just default to "biodrive"-me_ to do simple tasks if it's feasible and easy, the K.I.S.S. principle.
One bit of advice, you just cannot beat insulation on payback and useability. Look into the "superinsulating" concept of structure design. It's very googleable. You shoot for R-55 floors walls and ceiling, and you can almost eliminate much in the way of heating or cooling, you can get it down to a ridiculous small level to maintain a decent comfort zone. The one house I worked on, back during the OPEC oil shocks, as a serious retrofit, we built interior walls around 6 inches away from the existing walls, then used blow in insulation to fill it up, then normal drywall to finish it. The old windows got replaced with triple panes, and much work on the various cracks, etc to make it tight. It's an *amazing* difference. In a lot of cases, just normal lightbulbs and inside cooking and whatnot is sufficient "heat" in the winter, with the furnace only turning on occassionally. similar with the cooling, the AC just won't run that much. dollar for dollar no other technique can touch it. Insulation is not sexy, but man it works! It's a serious "silver bullet" alternative energy technique that isn't being explored much. People "get it" woith high MPG cars, they can understand that, but with their homes they will pop for a long term mortgage for some place that is the energy gashog equivalent of an SUV with fouled plugs running on flat tires uphill. I have no idea why this is so but it sure is. And the banks will give them a note for it! R-18 maybe cut the mustard back when oil was a few dollars a barrel, but not now.
The whole subject is fascinating, it's quite possible nowadays to not only have a totally energy self sufficient home, but also get a check back from the electric company every month, or at least bank kilowatt hour credits.
If you are going for active solar, now is a good time as you can combine a lot of tax breaks with tying the installation into your home note long term. Most folks go for a hybrid system, solar PV, thermal, wind charger, fuel generator, then a grid tie. It just depends on your location what is practical or not. You are about covered for juice then with any mixture of the systems, and combine that with a good sized battery bank. having a whole house UPS system is quite spiffy...... And greenhouses are just *neat*. I was just up in ours looking at the tomatoes and peppers and cabbages and whatnot..... while the outside garden is now mostly gone by for the winter. We even have some roses blooming in there and some tropicals, but I don't know if the heavy tropicals will make it this is the first winter and we don't really want to artifically heat it, just cost too much and I don't have that other composter heater built yet, just too many back burned projects behind now. What some guys have done is combine raising meat animals inside the greenhouse with plants, like chickens or rabbits. The animals throw off good heat 24/7 and can eat a lot of the vegetable scraps. You can put tanks for fish as well and use the water for thermal storage. Lotsa neat stuff you can do. If you go the small meat critter route, you can use their, uhhh, how do you put it, their "exhaust", heh, in a methane digester to get burnable gas.
good website for you (dead tree magazine as well)
http://www.homepower.com/
you'll go nuts there, double heh
Somebodys spend million dollars to make water pass trough his microwave oven
I think many people here have a misconception that resistive heating is 100% efficient. IT IS NOT! - Yes, it does convert 99.99% of the energy into heat, but there are more efficient ways to generate heat - the HEAT PUMP. If you were to hook up a huge peltier to the bottom of a hot water tank and place a giant heatsink rod into the ground, the pelter would PUMP heat from the ground into the water in addition to all the extra heat that is generated by the peltier.
A 20 kW microwave radiator in every home?! And people were worried about the effects of cell phones and overhead transmission wires.
"Consensus" in science is _always_ a political construct.
If the water temperature goes above a safe limit or the pressure exceeds a certain value the valve opens and dumps the hot water to the drain.
This prevents the water from ever reaching the boiling point and prevents the tank or plumbing from rupturing due to an overpressure situation.
No need for any open tanks in the attic or any other Rube Goldberg solutions. The valves are extremely reliable and inexpensive (about $10 US).
Putting moderation advice in your
Actually microwave cookers/heaters generate microwaves! The microwaves in turn vibrate water molecules to the point where they heat up due to friction. As a result microwaves are something like at most 65% efficient at heating if I remember correctly because of the wasted microwaves that don't make contact with the water.
I can't believe how many posts on this forum are completely wrong.
The goal of computer science is to build something that will last at least until we've finished building it.
I have lived in houses with electric storage and instant, and gas storage and instant water heaters, in metro and rural areas. Gas is better because of cost, but there are some current electric systems which given the right circumstances are very efficient. When overall purchase and running costs are factored in, I doubt, based on my experience, that using microwaves would be cheaper/better then resistive electric heaters.
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This has been around for quite some time. Here is one example I first found well over a year ago:
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http://www.electrosilicagroup.com/heat/technology
The water flows through a ceramic pipe inside a tuned resonant cavity where it is heated and flows out to it's destination. Nothing at all new about this at all. Someone just got hold of some marketing hype.
Way back in University, I created a mobile microwave emitter (well, battery powered) that I carried around on a shoulder-strap.
There was about 30 minutes of power for a sustained emission - which I used to "plow" my driveway every once in a while at my Northern Ontario home. So much faster than shovelling..
It was fun for a while, but extremely dangerous. I stopped using it when neighbours starting coming over to see what I was doing - I had to tell them that was a simple chemical reaction that was causing my snow to melt which was triggered by my "sound emitter".
Loser-
Fuck off. Get a life.
Heat pumps, are the only thing capable of getting over the 100% efficiency of electric coils. France has had buried heat coils and heat exchangers for a while now. Air conditioning is the way to go with pre-heating.
Many countries use the excess heat/hot water from nuclear power plants for office heating, and hot water/ water heaters for the local schools, then prawn/fish aquaculture in the middle of winter.
The British are innovate, like the Americans a few balmy scientists have made their own plutonium batteries to ease their electricity bills - just like space satellites are powered.
Then there is the Russian/Hungarian way, a 5*7ft brick +tile stove on the sunny side of the house (huge thermal mass) and run copper pipes through it for the shower.
The moral of this, is just how hideously inefficient and uninsulated modern house are, relative to all those nice hobbit burrows in New Zealand.
(You can't see the light because you don't use transparent pipes, do you?)
I know you're joking, but a lot of newer houses around here actually do use transparent tubing for plumbing instead of copper. It's much quicker to install, quieter and more efficient.
"...or natural gas heaters that heat up water on-demand...and the second is not available to everyone, especially those in rural areas" WTF!!! I'm pretty sure i've seen propane models, and trust me, there is a lot of propane in rural areas. Ahh there we go, Froogle to the rescue. I realize that the summary said natural gas, but I feel it was cheap of them to not mention propane.
-+-=-+-=-+-=-+-=-+-=-+ *** http://www.mountainfort.com *** +-=-+-=-+-=-+-=-+-=-+-
Bush has more than a smartcar to be thinking about: http://tinyurl.com/exp99 / http://www.newpath4.com/enginewow.htm . Then there's the End of the World Engine: http://www.newpath4.com/millenialdawnpowerandlight secure21.htm . The first runs on water & air & the 2nd doesn't use any fuel at all. Looks like going to be a Jerry lee Lewis moment coming soon, a whole lot of shaking going on, is all I have to say about that. mailto:Good7Riddance7toAll7Creosote7Engines777@new path4.com for autoresponder.
Propane if you like. In rural areas we need to harness methane emmissions - think of it ! Free power frfom the cow-house ! (Not to mention the local truck stop).
How many beans make five, anyhow ?
Yours seems to me to be a very good analysis.
We keep our water heater at almost boiling temperature. It's like learning to use a stove. We need to know that the hot water is HOT. In any case, there is no need to buy a special device; just turn up the thermostat on the water heater.
There is nothing special about Legionella bacteria. There are millions of kinds of bacteria, and they are everywhere.
The electric shower head water heaters, available everywhere in some countries for the equivalent of $10 U.S., boil the water next to the element, so I doubt that they harbor bacteria in the interior. Certainly there is always bacteria on the outside of anything moist.
Time is Nature's way of keeping everything from happening at once... the bitch.
Here's where you can do something good. Find that absorption spectrum, if you can. Take it, mail it, whatever... get it to your old teacher. Make sure that s/he doesn't repeat that particular bit of misinformation ever again.
Time is Nature's way of keeping everything from happening at once... the bitch.
I wonder how much a gas storage tank setup would cost to implement? If the peak/offpeak price differential was significant enough, it might become ecconomical to buffer one's gas usage by "filling the tank" at off-peak rates. I seem to recall residentail filling systems for natural gas automobiles - this would seem to be a similar set of technical issues.
These folk seem to have such a system available - and they claim 40+% efficiencies:
http://gfxtechnology.com/
http://www.gfxstar.ca/
Why is this cool? Well, until now, you had two options: electric heaters that keep a large amount of water hot at all times, or natural gas heaters that heat up water on-demand.
I guess my "natural gas heater that keeps a large amounts of water hot at all times" that I installed last month must be imaginary.
...the above comment wasn't by me.
No, really.
Christian R. Conrad
mail me at iki.fi ; same user ID as here