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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."
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.
Really? So none of the electric "tankless" water heaters on this page actually work then?
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.
They work fine, we have got one. And it's certainly possible to get uncomfortably hot water from them.
Switch back to Slashdot's D1 system.
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 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.