Wednesday, July 16, 2008

Saving private power

Something a little detached from the normal theme, this is about saving energy.

Using nothing else, but just your CRT monitors. Here is a very interesting (although a bit long :) ) article talking about power savings and CRT monitors. This post is about is the impact of such power saving.

By the way, a CRT monitor is the big, boxy old display that used to come with older PCs. And sometimes with newer ones as well.

We, in India, (at least in our part of the country, that is) are faced with constant power shortages. In fact, barring major cities, it's been quite a few years since we had electricity 24x7. As a result, small businesses, students studying for exams and people critically dependent on electricity are at a huge loss. That's why I urge you to reconsider your electrical usage. But without being too preaching, here are some suggestions you can very easily act upon. And, as promised, just by using (or not using), your CRT monitors.

It doesn't take a lot to save electricity through correct use of monitors. Just keep in mind these simple steps to avoid wastage of electricity and their effects:
  1. Switch Off all your monitors before going home every evening without fail. You might be ensuring every night that one household receives evening light for one week.[1]
  2. Switch Off all your monitors if you are going away from your seat for more than 10 minutes. Better still, have the operating system do it for you through the power saving options. Every day, you could ensure that a medium shop stays open for an hour more.[2]
  3. Keep your brightness and contrast levels to an optimum level. The less bright your display, the less power it will use.[3] You would be helping your own eyes see better for longer.
Some important points to be noted also, are:
  • Switching the monitors Off manually is the best option. Even if the monitors have an auto-off feature, that is like switching the TV off using a remote control. They still require about 2 watt of power.[4]
  • Screensavers save screen pixels. They don't save power. The monitor is still On. They may only save some power if a screensaver has a black background, causing the monitor to use less power. But not as less as when it's switched Off.
  • LCD screens are much more power-friendly. They use up about 20-30 watt of power. But they still should be switched Off when not in use. 20 is not equal to 0.
  • LCD screens are indifferent to brightness levels. They use up almost the same amount of power at the most bright and least bright settings.[3] Even then, the less bright screen uses less power.
These steps are simple enough if we make a habit of these things. Is forming a habit of switching Off your monitor whenever you get up to leave the room that tedious? I don't think so; what do you say?

  1. Simple calculations again. A sensible home in areas outside Pune will use about 75-80 W for evening lights (two tubes / 4 CFLs). A 150-160 W monitor burning for 12 hours every night translates to the evening lights burning for 24 hours, which is about 7 days with 3.5 hours of evening lighting every day. That's how much the average load-shedding in the evenings is.
  2. Lunchtime, tea-times, calls and meetings and some other gaps in between mean we're don't use our monitors for about 2 hours everyday during the daytime. For a medium sized shop requiring power for lighting mainly (e.g. a barber, grocer, medical shop), the consumption may be around 300-320 W (8 tubes / 16 CFLs).
  3. Here is an excellent blog entry giving details of an informal study by a person named Kedar Soman. He gives graphs of power consumption measurements as well.
  4. In the same blog entry, Kedar mentions this 2 W usage. He mentions also an interesting observation that some models of TVs consume up to 20 W in this idle state. So be careful next time when you touch that red button on the remote. :-)

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