Company Develops Microwave-powered Water Heater 505
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."
Kill germs too? (Score:3, Interesting)
Re:microwaves more than 100% efficient? (Score:5, Interesting)
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
Re:Why didn't someone think of it before (Score:3, Interesting)
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.
Possible alternative explanation (Score:3, Interesting)
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.
Significant energy savings from point of heating? (Score:1, Interesting)
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?
Re:microwaves more than 100% efficient? (Score:2, Interesting)
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
Re:that's more like it (Score:3, Interesting)
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.
Re:that's more like it (Score:3, Interesting)
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.
Re:that's more like it (Score:1, Interesting)
Mandatory Scotty quote (Score:3, Interesting)
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.Re:that's more like it (Score:5, Interesting)
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.
Re:Kill germs too? (Score:3, Interesting)
This is incorrect, but a common misconception. Microwave ovens work by dielectric heating of the material inside them. Certain materials are more efficiently heated than others, but there is no tuning to the water molecule involved. Look at the frequency response of the absorption coefficient of water to electromagnetic energy, there's an excellent one on page 291 of the second edition of Jackson's _Classical Electrodynamics_ (that graph is one of the most dramatic I've ever seen, just for so well answering the question "why have our eyes evolved to see light only on the range 400-700nm?"). On that graph, you'll see that the absorption coefficient is smoothly increasing between 100 MHz and 10 GHz, there's nothing magic about the frequency chosen for microwave ovens, it was an available frequency in a band not reserved for communication.
No, another example of cut and paste... (Score:5, Interesting)
This "article" is a press release being marketed as news by the Globe and Mail. Here is my letter to the editor.
Re:that's more like it (Score:3, Interesting)
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.
tankless in rural areas (Score:2, Interesting)
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.
Re:that's more like it (Score:4, Interesting)
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 [belizenorth.com] 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.)
Re:No, another example of cut and paste... (Score:1, Interesting)
Resistance-based heaters are slow. Thus they need to be always heating (to offset heat loss from the tank) just in case someone turns on the hot water somewhere (an alternative is to put them on a timer based on your water usage schedule). (Actually, I'm impressed by that 99.9% efficiency rating you've claimed, given that would require only
According to the press release the microwaves can heat water on demand, rather than maintaining a hot tank, so it comes on when the water starts running and stops when the water isn't needed. Even if it is a little less efficient in terms of energy->hot water, the fact that it only runs on demand should mean you use less electricity (lets pick random numbers and say to get the same temperature of water it runs at 1000kW instead of 500kW like a tank heater, but you've set a timer so your tank heater comes on at 5AM and runs until the end of your 30 minute shower at 6AM. That's 750 kilowatt hours for the tank heater, and 500 kW hours for the on-demand microwave heater.) It wouldn't be a good deal if you used hot water 24/7, but for most household uses, it would be great.