Don't bother designing green anymore?

Hi Cabe,

As a designer of switch mode power supplies i'm in the frontline of thing about ''green''. Green in our business means: boosting efficiency as high as possible, schrink standby power to as low as possible and simulating the power supply as an perfect resistor, by using a power factor corrector at the input stage. This last one also benefits the cashflow of the energy-supplier :-)

As far as looking to my designs i am able to deliver a 5W converter which has 0.25W losses when using at no load. In practice this will mean that the application has less than 500mW input losses at 250mW output power (250mW to keep a standby module alive). On the upper range in can deliver 500W peak power (350W nomimal) at an efficiency close to 90%.

These figures seem to be state-of-the-art and ''green'' but when you look at an application you must realize that the effiency of a application is close to 0% ! For example a TV will generate light an sound and an amplifier/speaker generates sound. Sound and light are really low power ouputs! ;-)

To give you a nice example of wasting power: A class AB amplifier can easily dissipate 50W in it's output stage at a delivered output power (to the speaker) of 1W. (the speaker itself will waste much of this energy in it's coil, and little is left to be converted into sound). Nowadays there are Class D amplifiers which are in general 'switch mode power supplier'-like circuits which have a very high efficiency. I think that Class D should be the standard and the other energy-wasters should be banned by law!

So the summarize. Yes, it is good to think green but it is almost useless as not everyone has to same intention/approach. The end-customer is responsible for the effective use of the device (turning off a TV when not used, things like that). I really think that goverments should make extra laws for pushing the industry to think green. For example, if a device is not green designed there should be an extra environment-tax which adds to the salesprice (this will make the competitor-position worse and is therefore self-regulating). 

I'm getting interested in alternative energy sources and smart grids. That is; generating (or converting energy) from wind, water, sun and converting this to grid voltage. If you generate more than you need for yourself you deliver the energy to the grid (and you get paid for the energy!) In the very near future i will start to design a grid converter with possibly a photo-voltaic front end. This converter will make maximum power tracking of the solar panel for highest efficiency.

Best regards,

Enrico Migchels

Power conversion design engineer

Heliox B.V.

Best, The Netherlands

www.heliox.nl

I agree with Enrico in that any new design should start with a specification and that would normally define the power consumption of the product. For battery powered devices efficiency is paramount because it determines the size and cost of the batteries and the run time.

I can't agree with Enrico about audio amplifiers -  he can listen to power supplies if he likes but I'm staying with linear power amplifiers. Of course with good design we can have a linear output stage AND high efficiency.

I certainly think we should avoid any more silly laws telling us what technology to use in a product. Now that incandescent light bulbs are being outlawed we have mercury being dumped in landfill or the atmosphere when CFL bulbs are disposed of.  We don't need taxes to make us choose product X or Y - the cost of energy will guide us perfectly well.

Is Enrico happy to be paid a commercial rate for his power fed back to the grid (in which case he will put his money into home insulation and nuclear power stations) or is he hoping for a subsidy from some one. (In the UK the recently announced feed in tarrif for home generated power is at least 10x its real commercial value and this is to be paid for by a levy (tax) on other electricity consumers.)

Hi Michael,

Personally i'm not a critical listener so i'm the one which can never tell what kind of technology is used within a power amplifier by listening. On the other side, my eyes can! On of the major benefits of Class D amplifiers is the power desity, so the volume of the device is significant less by using a cmbination of SMPS + Class D. I see Class D devices popping up everywhere, also in the upper segment of consumer electronics. The future will show that switched circuits will take over the market, as did the semiconductor took over the market of the vacuum tube. But on the other hand. there are still vacuum tube amplifiers being sold :-)

In general í'm not in favor of subsidy but this kind of economic stimulans is used in our society. If the total cost of nuclear and other installations was incorperated in the enery-rate, the alternative energy sources would be pretty much competitive. The aternative energy sources are not a real replacement for the big installations yet, as the energy infrastructure is not defined. I see them merely as an add-ons to the power grid, but as the power grid will be smarter in the future, the alternative energy sources will grow in importance.

Best regards,

Enrico Migchels

Power conversion design engineer

Heliox B.V.

Best - The Netherlands

www.heliox.nl

I dont really understand your point about "alternative" energy sources being competetive:

This is copied from  report produced by the Royal Academy for Engineering which you can find at

www.raeng.org.uk/news/publications/list/reports/Cost_of_Generating_Electricity.pdf

You must also take into account that homne generated electricity is less efficient to generate than in bulk and MUCH less valuable since it is power generated when the winf blows or the sun shines rather than when it might actually be needed.

Back to the audio - decent speakers are always bigger than decent amplifiers for real lsitening. If you are listening to MP3s or DAB radio it probably doesn't matter too much about the power amplifier technology - the signal has been degraded beyond redemption already.

Hi Michael,

Trying the calculate the cost of a kWh being generating is really diffiult. I would guess that when you take all costs in consideration, meaning a nuclear plant plant and processing plant for depleted fuel and more of this the figures would be different. It is true that the value of solar and wind power is less but in a smarter grid the value can be increased.

I really like listening to MP3 :-)

Best regards,

Enrico Migchels

I'm glad to hear engineers are trying to protect the environment, even in small ways.

But let's go a bit deeper. Do you consider who makes the parts in your design? And is that company making the components with more or less of an impact on the ecosystem vs another manufacturer? If you are going to these lengths, energy used to create the parts of any one design must be considered.

Take Fiji water as an example. They have to ship the water via large container ships that spew waste into the ocean. Where one can pick up a local bottled water that doesn't have the brand name, but has a mere fraction of the impact on the environment that Fiji does. (As a side note; after learning this some years ago, I stopped drinking Fiji water.)

I have worked for several companies in the past that would have dumpsters full of electrical product fabrication waste every week. I raised concern over that a few times, but meeting the deadline or price point was more important. And the garbage pileup was never addressed. I don't like this style of development, and I hope to see a change in our sector.

Perhaps more software emulation packages? (ie: Multisim)

Cabe

Hi Cabe,

I worked at Philips, they had an active policy of RoHS-complaince. As everyone does nowadays, i guess? That's a start. Suppliers also had to sign a document stating there there shall be no child-labour involved with the products. There were events that we had to scrap suppliers because they were not willing to give this legal statements. These things are a start in moving towards taking responsibility towards other people and environment.

Best regards,

Enrico Migchels

Power conversion desgin engineer

Heliox B.V.

Best - The Netherlands

www.heliox.nl

Hello, all.

I realize I am several days behind the main flow of this thread, but I had to pipe up about RoHS compliance. Enrico, you mention that you suppose every industry has gone over to RoHS, but there is one notable exception: aerospace and defense. I work for a defense contractor and we regularly exempt our products from the lead-free requirements of RoHS policies. This is because of the tin whiskers (which cause shorts) and poor shock and vibe performance of lead-free solders.

In fact, there are several new mil specs (military specifications) that explicitly prohibit tin-only solders or solder finishes. Also, there's the "Airworthiness Advisory AA-05-01, Lead-Free Solder" document (by the US Air Force) that concludes: “Though there are many alternative solder alloys available to replace traditional tin-lead, none of them has passed the reliability testing required of aerospace-quality hardware.”

So, although the commercial Airbus plane you're riding may be lead-free and green, rest assured that American missles and airforce planes will last longer and have higher reliability.

Seriously, though, I fear that the leap to lead-free solder is going to be paid back in catastrophic failures before we learn that a little lead is a small price to pay for critical systems such as transportation, medicine, and others.

Hi juleigh,

I was aware of the 'special treatment' for the sectors you describe. Lead-free soldering is also not easy in a development stage. The transition from liquid to solid is too short. It results in bad solderjoints. I still use PbSn, but customers insist than even sample deliveries are lead-free. Sometimes this is checked.

I know about the tin-wiskers. Have you even head about zinc-wiskers? They cause also shorts and are found when cabinets are zinc plated (electro-plating). This is really nasty. The biggest problems occurs in computerrooms where the floors contain zinc plated frames. After opening the floor (for rerouting of cables) the computers are more likely to go defect because of air-born zinc parts sucked in by the blowers. The zinc needled are so small that the air filters can not prevent them from enthering the machine.

Best regards,

Enrico Migchels

Whoa  --  At least in the UK for over 1/2 the year all electronic stuff is 100% efficient. I.e. any "wasted" power is dumped into the room, where the central heating has thus to work less hard. Same goes for those old and good light bulbs.

And wait, since when was class D the most efficient audio amplifer topology? See eg http://www.audiumsemi.com/

And while we are at it - your proposed "non-green" tax - well how much energy do you think will be wasted by the quango setup to administer that one?

Plus, yes one can get paid for putting energy back into the grid, but is that green? The cost is subsidised and is not a real price, if it were real maybe it would be uneconomic for you to install power generating plant at home.

R