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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."
Microwaves kill various germs too, don't they? They should market this as both a water heater and a sanitizer.
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That's if you just count kw->BTUs, but that's not what they're talking about. They're talking about a complete system. You can't heat water efficiently for your showers with coils because they take time to heat up, they waste energy when they're cooling down and you're not in the shower, and because it just takes so darn long to do it without a huge amount of coil (which would use more energy in heatup / cooldown), you have to store it hot. And storing something hot is just about the least effecient thing you can do in this universe, and as such "the system" tends to be quite inefficient. With a magnetron it's not seeping heat into the air while it cools down (well not within an order of magnitude the same amount), it's more or less instant-on. So you're not leaking your power into the air in your heater cupboard and the frame of your house. The only thing newsworthy about this though is that it's taken so long for someone to think up and implement a viable microwave solution.
Of course, my ex housemate ben only knows to get out of the shower when it gets cold, so I apologize for my mate using up all the world's energy when he gets one of these. On the plus side he'll eventually wash down the sink and his missus will turn it off.
Yes, I understand the OP would definitely know all this, and was just trying to make a point, but I just thought I'd elaborate^W ramble a bit with my AU$0.02
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Maybe because it's not really a great idea. MW ovens are efficient because they just heat water, not the air etc in the oven. But an immersed electric element is already very efficient at heating water. If I want to boil more than one cup of water I use an electric heater, or a kettle on a stove. If there is a breakthrough, it would be in making high-powered (by comparison with domestic MW ovens)as cheap than an on-demand electric heater. That's assuming it really is as cheap, if it's not then it's just a novelty item for gadget geeks &/or Japanese.
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
Well ~30% of germany gets its hot water supply from
:-) more blackouts to you.
electric "on the run" heaters.
Most nowadays have "blankdraht" i.e uncoated wire
heaters giving short of 100% efficiency and a fantastic
lowlatency response.
Mine has 24kW, electronic temp control and heats
~10liters/minute from ~10C to 35C.
3phase 380V AC is a mandatory requirement and the
current draw is ~35Amps per phase.
Core advantages are no standby losses and low investment.
A Microwave heating system would use more energy
as the RF generation by Magnetron is 90% efficient.
US AC won't be up to it anyways
Here in East Texas we run the AC 7-8 months a year. We, typically, have the hot water heater in the garage so as not to run up the AC bill. What makes the most sense, here, is a solar hot water system. There would likely be only 10 to 15 days a year, if that, where the a solar hot water system would not be able to meet all hot water needs.
In by gone years a solar hot water system would pay for itself in about seven years. However, with the increase in natural gas prices over the past year I'd be willing to bet the time it would take to recover the cost of installation has dropped to about five to five and a half years.
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I didn't think that this was a problem anyway.
I have an electric shower. It is a small unit (about 8 inches tall, 5 inches wide and 3 inches deep, which has all the controls and houses the heater) and can adequately heat the water running through it to give a decent shower, and gets hot enough within seconds. It does draw around 10kW on full power, but for a microwave heater to heat the same volume of water would require much more than this (due to the inefficiencies noted).
So I really don't see what this microwave on-demand heater is solving here - we've had on-demand electric water heaters like my shower for decades.
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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.As the water flows the pressure would close a switch inside the showerhead and heat the water electrically as it sprayed out. Costa Ricas tend to be shorter than Americans so these pipes are invariably mounted about 5'10" off the ground, forcing many to squat down a little bit to get under the head. An accidental brush up against the showerhead with give you a quick reminder to squat back down again. The unfortunately arrival of a moderate earthquake (fairly common) could also bring about a zap.
In one apartment the occupants (Americans, actually - Costa Ricans aren't this stupid) had spliced the wiring (120V @ 50Hz IIRC +/- 10% to allow for the ever-changing conditions on the line) with masking tape. I happened to be in there at the moment the tape burst into flames making me one of the only people in the history of the world to have been using a shower that caught fire.
If the g'vt kept the data on you that google does you'd better believe you'd be calling it "doing evil"
This "article" is a press release being marketed as news by the Globe and Mail. Here is my letter to the editor.
Well, it's not improved. The microwave idea is *highly* inefficient and this article sounds like someone advertising for VC. When I was in Argentina over 20 years ago they had electric on-demand heated water (at the tap). It worked fine and I expect that they have better ones now. Getting heat to the water efficiently is a pretty simple matter. You have something to increase the surface are of the heating element relative to the water just like a CPU cooler does and as long as the surface area per volume is high enough, you're fine. It's not rocket science you know.
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.
If only that had been the only electric oddity I encountered.
I believe I saw circuit breakers a total of three times. I never saw a single glass fuse. What does this leave? Little pieces of aluminum that look like little wrenches. When the current gets too high they melt/vaporize. At one apartment the landlord never had spares, but would cross the two terminals in the fusebox with several turns of his solder. Who knows just how much current it would take to melt it.
Arc welding is very common - on/off switches or plugs for the welders are not. They would usually scrape off some insulation on the power line, cut off the plug on the end of the electric cord, bend the wires into a hook and set into place. To turn the machine off one swats in the general direction of the wires until they disconnect.
The electric showerheads never gave me any major problems - except for the time the americans spliced the wires with masking tape. Everybody said that they were perfectly safe (to reassume me, I suppose) but I never heard of anybody who had been electrocuted, nor did I ever meet anybody who had even heard of somebody getting zapped. Again, maybe they were just trying to reassume me.
By the way, I found a picture of the showerhead... something that most people in this country (or many other countries) have ever seen. (I didn't read the article there, just found the picture.)
If the g'vt kept the data on you that google does you'd better believe you'd be calling it "doing evil"