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n:vision 23W (100W equivalent) compact fluorescent
New bill would mandate that light bulbs produce 120 lumens per watt by 2020

It looks as though energy efficiency is still a big priority for municipalities and countries across the globe. We've already detailed energy-efficient LED lighting efforts put forth by Raleigh, NC. We've also discussed how Australia and the European Union (EU) plan to get rid of incandescent light bulbs by 2009. The United States is also moving towards ushering out inefficient lighting with H.R. 1547, which was published on March 15, 2007.

The bill (PDF), which was submitted by California representative Jane Harman, indicates that light bulbs which have an overall luminous efficacy of 60 lumens per watt (lm/W) will be prohibited by January 1, 2012. The energy requirements get progressively steeper every four years. On January 1, 2016, the requirement will grow to 90 lm/W and will reach 120 lm/W by 2020.

A traditional 100W tungsten incandescent light has an overall luminous efficacy of 17.5 lm/W. A 23W compact fluorescent (100W equivalent) has an overall luminous efficacy of 60 lm/W.

Exemptions could be made by the Secretary of Energy for certain applications where it wouldn't be feasible to use energy-efficient lighting. These include applications related to military, medical or matters of public safety.

If an exception is made by the Secretary of Energy, that still doesn't give entitle the recipient to a free pass to continue using outdated technology. The exemption will only be in effect for two years after which the current enacted requirement will have to be adhered to.

The bill also notes that consumers and businesses will be given incentives to encourage the use of energy efficient light bulbs.



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By Mitch101 on 3/22/2007 12:42:42 PM , Rating: 3
We need to come up with a new lighting voltage and current. 120VAC is very inneficient when having to convert it. I would like to see a 12VDC light sockets. Might also help solar panels because you would no longer have to convert DC to AC back to possible DC again.


By MrBungle123 on 3/22/2007 12:46:17 PM , Rating: 4
AC is the most effective way to transfer power over long distances.


By BigT383 on 3/22/2007 1:18:01 PM , Rating: 4
Though, you could start seeing lighting transformers being built into, say, the house- right next to the breaker box in the basement or something.


By borismkv on 3/22/2007 1:44:01 PM , Rating: 2
That would result in even lower efficiency, since the power cables running from the transformer to the light sockets would work as a giant resistor. The longer the cables, the more power you lose. That's the main reason AC is more efficient over long distances, it doesn't lose nearly as much power from cable resistance. Ultimately, you'd need to include the transformers in the light sockets themselves, which would cost a lot more money than just having one transformer.


By repatch on 3/22/2007 2:34:36 PM , Rating: 2
Sorry but you are completely wrong there. Whether AC or DC, the power loss due to the "resistance" of the line is identical (for relatively low power levels).

In fact, if you want to get really technical, the effective resistance of a line is HIGHER for AC then for DC due to the skin effect, however at the power levels we are talking about (wires in a home) the skin effect can be ignored.

The ONLY benefit AC has over DC is you can use a transformer. This allows the power companies to step up and down the voltage very simply and efficiently, reducing the current flowing through the transmission lines.

Since power loss in a wire is I2R you can save alot of power and use much thinner cable by sending a high voltage.

The problems with AC are the skin effect (which, described in a simplistic way, results in AC current only flowing through the outer portion of the wire, giving an effective higher resistance, and higher power loss) and impedance coupling to ground. For VERY long high power lines DC is actually used, an example is the James Bay project transmission line in Quebec Canada.


By borismkv on 3/22/2007 3:17:40 PM , Rating: 2
Thanks for the correction. Now I get to add another thing to the list of reasons I'm glad that particular electronics professor retired :D


By Howard on 3/22/2007 4:01:46 PM , Rating: 2
Skin effect is negligible at 120Hz.


By Howard on 3/22/2007 4:05:54 PM , Rating: 2
Oops, meant to say 60Hz. Specifically, the skin depth at 60Hz is about 8.5 (IIRC) mm, meaning that skin effect only kicks in at a diameter of about 17mm. If 17mm wasn't enough for the current, it would probably be at a high voltage anyway.


By Hawkido on 3/22/2007 4:40:59 PM , Rating: 2
quote:
The ONLY benefit AC has over DC is you can use a transformer. This allows the power companies to step up and down the voltage very simply and efficiently, reducing the current flowing through the transmission lines.


I can think of another benefit or two:
1. You can easily convert AC to DC, the reverse is incredibly wasteful and complex.

2. When DC shorts out the whole line lightes up like a lightbulb filiment. Causing fires in houses along the entire trail all the way back to the power source. Ever seen a car's DC wiring fry? You gotta replace the entire wiring harness or else use a butt load of electrical tape. When AC shorts out heat is only generated at the short.

3. If you are planning on running DC to everyone's house, I suggest you pay their life/fire insurance for them as well.

Read Tesla's work, he wanted the Hz in the 200 range for Flourescent bulbs. The light emitted is far more solid and brighter and bulbs longer lasting at that Freq.

Also look up the number of technologies that require AC vs. DC. Generators generate AC electricity, you will loose half the generated amount of electricity when you convert it to DC. (Sine wave grounded at <0 vs. current flowing in the reverse direction <0)


By saratoga on 3/22/2007 7:17:10 PM , Rating: 2
quote:
When DC shorts out the whole line lightes up like a lightbulb filiment. Causing fires in houses along the entire trail all the way back to the power source. Ever seen a car's DC wiring fry? You gotta replace the entire wiring harness or else use a butt load of electrical tape. When AC shorts out heat is only generated at the short.


AC and DC both do this if theres enough current in the short. Its not like AC doesn't heat the lines too.

quote:

Generators generate AC electricity, you will loose half the generated amount of electricity when you convert it to DC. (Sine wave grounded at <0 vs. current flowing in the reverse direction <0)


Rectifiers like you're describing exist in textbooks only. Modern DC supplies are typically 65-90% efficient for consumer level applications.


By knowyourenemy on 3/23/2007 1:50:29 PM , Rating: 2
Thanks for clarifying. My grandfather was one of those electro engineer guys from ages past, and he has always told me those massive power lines that go cross-country are DC... I knew some information presented here wasn't straight when someone argued AC is better than DC for long distances.


By Scorpion on 3/22/2007 1:18:28 PM , Rating: 2
Yes, see the rivalry between Edison and Tesla. AC is far more efficient for transmission.


By mino on 3/22/2007 2:17:20 PM , Rating: 3
Well, actually not.

AC is the most efficient way for <1000km and <1000 distances, for longer distances the DC(at ~1000kV, mind you) is more efficient(even including required conversion at both ends of the line).

I read a paper on this some years ago. It was based on electromagnetic theory aplicated for these scenarious.

The real reason it is no widely used is that in developed countries one usually does not transfer electricity over such a large distance.
AFAIK Russians built some such line in the 60's and 70's when they had many coal plants concentrated in single location and needed to transport the energy for their cities which were across the whole country.


By mino on 3/22/2007 2:18:44 PM , Rating: 2
<1000km and <1000 kV distances


By mino on 3/22/2007 2:23:09 PM , Rating: 2
should have been:
<1000kV and <1000km distanc...


By kensiko on 3/22/2007 7:05:31 PM , Rating: 2
This is true, I did some research in the past about our line, in Quebec, that starts from the far north and goes to the US. DC is used for many good reasons.


By Oregonian2 on 3/22/2007 1:56:11 PM , Rating: 2
One wants to transport electricity at as high a voltage as possible. Losses are current times current times resistance, where resistance is that of the wire. So lowering the current by a factor of ten reduces the energy lost by a factor of one hundred. Increasing the voltage by a factor of ten reduces the current by ten fold -- for the same amount of energy. That's why the voltage is still pretty high going into the transformer that's usually installed for each very small group of homes and why one doesn't want it too low going into the home either. If anything the higher wall voltage (~220V) used in much of the world would be better (other than being a higher safety risk which is the primary tradeoff).


By repatch on 3/22/2007 2:38:33 PM , Rating: 2
Switching power supply technology reaches efficiencies in the 90%+ range, there is no longer a good reason to use lower voltages.

On top of this, 12V light sockets are foolish. Lower voltages mean higher current flows, higher current flows mean larger wires and higher losses in the wires. On top of this is the complexity of having multiple voltage busses in the home (people get confused enough with 120V and 240V sockets).

Why do you think the car manufacturers are slowly moving away from 12VDC systems in favour of 40V+ systems? Less copper, less weight, less cost.


By Mitch101 on 3/22/2007 2:58:32 PM , Rating: 3
I was thinking recessed 12v lighting with a single solar panel on the roof should collect enough solar energy to power all the lights in my home providing it didnt have to go through the whole DC-AC transformation. I would put up one nice solar panel to have free lighting. They should be able to do it after all they have those driveway lights that are solar panels and small solar panels in usually not direct sunlight do pretty good. When the 12v battery is filled you could then start doing DC-AC conversions selling the electric back to the grid or powering your 120VAC items if you choose.

The problems lie in the solar panels taking energy and doing the whole DC-AC conversion when we should be designing items that would work with the DC power supplied by solar panels collected at a battery point.

My 12V spec was taking FREE energy from sources like wind and sun into the home. Not getting it from the electrical companies 120vac and converting it to 12V.

I also read some time ago about a guy who ran fibre optics through his house and how a single light was lighting all the rooms in his home. Cool but impractical if you wanted to make changes to the home.

If using a source like solar then LED's might be the most practical light sources.


By Fritzr on 3/23/2007 5:24:34 AM , Rating: 3
12v DC appliances are readily available. Original purpose was to allow them to be powered from an automobile cigarette lighter. Solar systems standardized on 12v DC to take advantage of this existing tech base.

A fully solar electric home would use 12v appliances & lighting. A battery room stores excess power and supplies it to the house grid when the demand is above production.

Check back issues of Mother Earth news at http://www.motherearthnews.com to see examples of this in practice. There have been many other publications of this tech, Mother was simply easy to find while I was typing this :)

Here is the url for a quick search of the articles for "Solar Power"
http://www.motherearthnews.com/google-search.aspx?...


By frobizzle on 3/23/2007 8:17:58 AM , Rating: 1
quote:
A fully solar electric home would use 12v appliances & lighting. A battery room stores excess power and supplies it to the house grid when the demand is above production.

A battery room? Let's all hope the batteries are not manufactured by Sony!

(Let the mod downs begin!)


"A politician stumbles over himself... Then they pick it out. They edit it. He runs the clip, and then he makes a funny face, and the whole audience has a Pavlovian response." -- Joe Scarborough on John Stewart over Jim Cramer














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