April 23, 2009

CFL (Compact Fluorescent Bulbs) Pros and Cons

Speaking on April's 22 Earth Day about his energy plan, President Obama reportedly called on every American to replace one incandescent light bulb with one compact fluorescent (CFL).

Well, like all other devices CFL has pros and cons. For reference, compact fluorescent bulbs use up to 75 percent less energy then traditional incandescent lamps. However, they do present potential health and environmental hazards. I wonder if the president's advisers fully informed him of all the impacts of using these bulbs?

Last year a research by UK's Health Protection Agency has shown that CFL bulbs can emit unhealthy levels of ultraviolet radiation when they are in close proximity to people. They said that the UV levels can be equivalent to that experienced outside on a sunny day in the summer and some precaution is warranted. The Agency's chief has suggested: "We are advising people to avoid using the open light bulbs for prolonged close work until the problem is sorted out and to use encapsulated bulbs instead." Hmm... Maybe we should use at home sunscreen and sunglasses with UV protection to protect ourself from these "green" energy-efficient politically correct bulbs?

Of course, many of us are not concerned of prolong sunlight exposure and would spend long time under the sun. Nevertheless, this WHO's warning should be taken seriously: "Prolonged human exposure to solar UV radiation may result in acute and chronic health effects on the skin, eye and immune system... Over the longer term, UV radiation induces degenerative changes in cells of the skin, fibrous tissue and blood vessels leading to premature skin aging, photodermatoses and actinic keratoses. Another long-term effect is an inflammatory reaction of the eye. In the most serious cases, skin cancer and cataracts can occur."

And although the above HPA's report says that when the CFL is further then 1 foot, the UV level is less than being outside on a sunny day in winter, for me it is not good enough. I personally don't want to subject my family to UV radiation [even a low-level one] for the sake of saving a few bucks, or helping a utility company, or because of anyone's political agenda.

Besides being a source of UV radiation, all CFLs contain mercury, a toxin that can cause kidney and brain damage (how come the state of California is not requiring the appropriate warning label?) Based on a research by Stanford University, the amount of mercury in one CFL bulb can contaminate more than 1,000 gallons of water beyond safe drinking levels. Now, raise your hands: who will bother bringing a burnt bulb to a special recycling place [if you can find one in your area] rather then throwing it in the trash?

And what if you broke the CFL? The EPA has a whole page of the clean-up instructions, which include the following sections:
Before Clean-up: Air Out the Room;
Clean-Up Steps for Hard Surfaces;
Clean-up Steps for Carpeting or Rug;
Clean-up Steps for Clothing, Bedding and Other Soft Materials;
Disposal of Clean-up Materials;
Future Cleaning of Carpeting or Rug: Air Out the Room During and After Vacuuming.

Hey, how about just staying with good old incandescent bulbs until a safe alternative will be developed? By the way, today's CFLs have a lousy power factor. For now a PF doesn't affect the residential electricity bills, but it does affect the utilities. Speaking about a safe alternative. If you are interested in $10 million cash, the US Dept. of Energy is offering this prize to create a solid-state screw-in replacement for the 60W bulb. If you can develop sufficiently bright LEDs and handle the packaging, give me a buzz- I would handle the AC-DC part of it, and we'll split the prize :-)

April 4, 2009

How to Measure Efficiency of a Multiple-Output Power Supply

On March 27, 2009, the US Department of Energy (DOE) published an amendment to its test procedures for battery chargers and external power supplies (EPS). The amendment includes provisions for measuring standby mode and off mode energy consumption and adds a test procedure for testing switch-selectable external power supplies. Since the document basically clarifies existing test procedures, which DOE originally could not formulate clearly, it is mainly clerical and would not be worth noting if not for one funny thing. The amendment still does not include a test procedure for multi-output power supplies because of "the number of stakeholder comments and the limited timeframe for this rulemaking." OK, here is a little background. The Energy Independence and Security Act of 2007 (EISA 2007) set Federal efficiency standards for certain types of adapters and single-output EPS for consumer electronics. DOE has a test procedure to verify this efficiency. However, this procedure [which is basically: multiply output volts times amps and divide by the input power under various loading conditions] was written for single-output power supplies. It has therefore left out a significant group of products, powering applications such as radio transceivers, video game consoles, and printers. On August 15, 2008, DOE proposed a procedure for the testing of multiple-voltage external power supplies. On page 6 of the Proposed Rule we read: "DOE is not aware of any existing test procedure developed specifically to measure the efficiency or energy consumption of multiple-voltage external power supplies." Huh? Millions of multi-output power supplies both external and internal including PC PSUs are being built around the world and tested for Energy Star® and 80 PLUS® efficiency compliance. Folks, how about this: take a 5th grader, ask him/her to add up volt-amps of all outputs, divide by the input power, and you are done! Seriously, the main obstacle for DOE seems to be the loading profile. The PSU's nameplate power is often smaller than the sum of the nameplate power of each individual output. So what's the big deal? Derate (scale down) the loads of all the outputs proportionally, so that their sum does not exceed the limit for the entire power supply. Of course, it would not be the worst case efficiency (which you would probably encounter if you shift the bulk of the load onto the lowest voltage outputs), but it would be kind of typical efficiency. Back in 2006, at the APEC conference, EPRI Solutions and Ecos Consulting presented their Enhanced Proportional Allocation Method for Loading Power Supply. Their method is incorporated by Intel in its PC power supply guides. DOE did propose to adapt the ‘‘proportional allocation’’ method. Nevertheless, the DOE 2009 final rule still reads: "Due to the limited time provided by EISA 2007 and limited resources available prior to the publication of this final rule, DOE was unable to address the large number of stakeholder comments received and decided to defer action on multiple-voltage EPSs to a 2009 rulemaking." In a private sector usually a new power supply will be designed, built and tested in this timeframe or in a shorter one. It's entertaining to watch how long will it finally take for US DOE to make up their mind on how to test the efficiency and to move to something else.