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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...
Most people in Japan have tankless water heaters, which makes sense in a country with a dearth of space and great surpluses of energy. It's just about the coolest thing ever; the element is heated in just a few seconds, and after that it's warm for as long as you care to shower. Combined with the automated bathtub courtesy of Osaka Gas, that fills itself and announces when it's ready in an attractive female voice, and I can't imagine ever going back.
"Give a man fire, and he'll be warm for a day; set a man on fire, and he'll be warm for the rest of his life
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.
Really? So none of the electric "tankless" water heaters on this page actually work then?
This is asinine.
A hot water heater's element - on demand or tanked - is submerged at all times. Therefore, almost 100% of the heat that it produces is coupled to the water - the only loss *NOT COUPLED* to the water is the heat which travels to the ends of the element where the terminals are. Electric heating of water by immersion heaters is close to 100% efficient. (We'll ignore the heat from the water which radiates through the heater; the energy loss from the hot water will occur with both conventional and microwave heaters.)
On the other hand, the magnetron, power supply transformer, rectifier diode and capacitor a microwave heater will require *all* dissipate energy, and unless they're all submerged themselves, the heat they produce will be lost.
How much heat is that? Consider, for a second, that most microwave ovens put out something on the order of 700W of RF power... and that most of their nameplates indicate they consume 1200W-1500W to do it.
So, watt for watt, will it elevate the temperature of the water more than a conventional resistance element? I can't see how, and I have more than a few University-level engineering courses in thermodynamics, chemistry and electrical engineering under my belt. It might respond faster than trying to heat up a relatively massive heating element, but... there's the magnetron.
Consider also that the magnetron is a vacuum tube which has a filament. Unless the filament is left on 24/7 (wasteful), it will take a moment to heat up before producing microwaves. A smaller and lighter filament would heat up faster, but would probably fail sooner during the repetitive on/off cycling this thing is going to experience.
Absolutely asinine. Finally the tankless water heater has one-upped itself in stupidity. Perfect for people with more money than physics knowledge.
(I come from a Northern climate where the thermostat is set to "HEAT" for 7-8 months of the year. The heat which radiates from the imperfect insulation of my water heater is simply lost *into my house* where it reduces the duty cycle of my furnace. Yet tankless water heaters are all the rage here, and I've installed dozens of them in the past year. They only make sense for compact homes in hot climates.)
Fire and Meat. Yummy.
I think the point was not that immersion heaters are inefficient in that way (i.e. in the true physical sense), but that because they cannot heat water quickly, they have to keep a large amount of water hot at all times in case it is needed. This is inefficient (not in physical sense) because the vast majority of the heat that is transferred to the water is lost to the atmosphere while the water sits around waiting to be used. Gas heaters, however, can heat water quickly (on demand), and thus no energy is being used to heat the water until it is required.
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.
This "article" is a press release being marketed as news by the Globe and Mail. Here is my letter to the editor.