原创 Power? Energy? Electronics?

 2013-12-30 14:22  3515 29 29 分类: 工程师职场

Electricity has brought numerous benefits to our daily life. But we should be aware of the energy consumption of different electrical appliances...

Recently I bought two drain meter from Taobao, for better understanding of the energy consumptions in my home.

Fig. The two drain meter, British Standard

Here are some basic measurement results:

Fig. Power of my Notebook (Dell V131, Intel i5-2450M, Intel Graphics 3000, Hitachi 1TB 5400rpm HDD)
Left: Idle in Windows 7, Right: Full-load by Fritz Chess Benchmark

When I use Notebook drain meter measure the power when powered by battery, it is 8-9W, the 2-3W difference should be due to the efficiency of conversion by the adaptor.

Fig. Power of my quite old Desktop Computer (MSI P35 Platimum, Intel Xeon X3210, Nvidia GeForce 210, WD 500GB Caviar Blue 7200rpm HDD, etc.)
Left: Idle in Windows 7, Right: Full-load by Fritz Chess Benchmark

Fig. Power of the Hisense 海信 26" LED TV - LTD26K16HK - in normal operation

In the TV's specification, the power consumption is 45W only... Why is the measured value larger?? I have not plugged in any hard drive or other USB devices... Due to error of the meter? Or else?

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I found that the power of power supplies varies much:

Fig. Power of a 12V4.0A Adaptor at NO LOAD
The above is an old adaptor, which was manufactured in year 2001.

Fig. Power of a 12V3.0A Adaptor at NO LOAD
Manufactured in year 2007. It consumes nearly no power under no load.

Fig. Power of a 12V2A+5V2A Adaptor at NO LOAD
The above is come with a hard disk enclosure.
Left: Power after just powered on, Right: After several minutes.

The increase in power consumption could be due to the heating effect inside. When semiconductors are being heated, the resistance decreases and current increases...

From the above, we can see that difference adaptors consume different amount of electricity even at NO LOAD. From my point of view, the difference was due to different designs, like when choosing switching controllers, there is a "minimum loading" requirement for older ones. Hence there will be a static power consumption.

->> Choose adaptors with higher efficiency level

Fig. Efficiency level marking on a Notebook adaptor

Newer adaptors have shown the efficiency level on their specifications.

For adaptors with higher efficiency level, not only the efficiency is garanteed, but also the power at no load (See figure below).

Fig. Source: http://electronicdesign.com/energy/understanding-efficiency-standards-external-power-supplies

***On the other hand, it is always better to unplug or switch off the adaptor / devices not in use, for reduced energy consumption, safety and longer adaptor lifetime (The capacitors inside usually dominate the lifetime).

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The development of new backlighting technology in LCD monitors also helps reducing energy consumption.

Fig. Both monitors have 1440x900 resolution
Left: BenQ 19" FP92W (fluorescent tube backlight) - 22W
Right: BenQ 19" G920WL (LED backlight) - 10.7W

I agree that when setting the monitors to different brightness will result in different power, but it would not vary much.

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Should we purchase new electrical appliances even if the old ones are working? (if money is not a concern) They are of higher energy-efficiency (also better functionaliy).

In my opinion, we have to strike a balance. It is because the process during manufacturing usually causes pollutions to the environment, and when we dump the old ones, if they are not well recycled, they will containimate our Earth and harm the people (and other living thins)...

More reading:

走进全国最大的废旧电子电器拆解基地：未来在哪里？
http://ee.ofweek.com/2013-07/ART-8120-2816-28700782.html