Saving energy
#1
Posted 2009-February-24, 13:29
#2
Posted 2009-February-24, 13:34
#3
Posted 2009-February-24, 13:57
1h is too long, there will be a break even point, but after
1h you certainly have passed this point.
Assuming you have enery saving bulp, there is phase in the
beginning, when the bulb emmits more and more light.
I would say, that the enery efficiency at this point in time is
not very good, but I may of couse be wrong.
Assuming a classical bulb: The question is, what is the difference
between the beginning and the sitiuation after 1h.
The only difference I can see is the heat, and the heat of the
small wire should reach the max. temperature a lot earlier than
after an hour.
With kind regards
Marlowe
Uwe Gebhardt (P_Marlowe)
#4
Posted 2009-February-24, 14:01
Robert
#5
Posted 2009-February-24, 14:03
#6
Posted 2009-February-24, 14:12
"light bulb" "turning on" energy
The break-even Uwe talks about appears to be less than a second.
That is a little surprising since I would expect wolfram to have positive resistance-termerature coefficient and therefor use more energy until it has reached it equilibrium temperature.
But it appears to be an urban legend.
#7
Posted 2009-February-24, 14:18
Incandescent lights (or bulbs) should be turned off whenever they are not needed. Nearly all types of incandescent light bulbs are fairly inexpensive to produce and are relatively inefficient. Only about 10%–15% of the electricity that incandescent lights consume results in light—the rest is turned into heat. Turning the light(s) off will keep a room cooler, an extra benefit in the summer. Therefore, the value of the energy saved by not having the lights on will be far greater than the cost of having to replace the bulb.
The cost effectiveness of turning fluorescent lights off to conserve energy is a bit more complicated. For most areas of the United States, a general rule-of-thumb for when to turn off a fluorescent light is if you leave a room for more than 15 minutes, it is probably more cost effective to turn the light off. Or in other words, if you leave the room for only up to 15 minutes, it will generally be more cost effective to leave the light(s) on.
#8
Posted 2009-February-24, 14:27
A discussion (in german) you can find here.
http://www.gutefrage.net/frage/wie-hoch-is...ten-einer-lampe
Basically (short summary):
The power is linear depend from the time, only at the beginning there is short
time intervall, which leads to a higher power consumption because of higer
voltage.
This is basic physics, every college book will tell you this.
So turning of the light even for seconds saves energy, but may reduce the
lifetime of the bulb.
So if you take into account the enery needed for producing the bulb than it
makes sense to not turning of the light for a short period of time.
Of course this is not a official internet source, I searched the net, but could
not find a better side.
With kind regards
Marlowe
Uwe Gebhardt (P_Marlowe)
#9
Posted 2009-February-24, 14:50
helene_t, on Feb 24 2009, 03:12 PM, said:
"light bulb" "turning on" energy
The break-even Uwe talks about appears to be less than a second.
That is a little surprising since I would expect wolfram to have positive resistance-termerature coefficient and therefor use more energy until it has reached it equilibrium temperature.
But it appears to be an urban legend.
I found it hard to google since all I found were articles about energy efficient light bulbs. That's why I enlist the help of my googling minions on the forums.
Edit: Ok thanks Helene, your google let me find mythbusters episode 69
http://mythbustersre...s.com/episode69
#10
Posted 2009-February-24, 15:11
#11
Posted 2009-February-24, 15:12
#12
Posted 2009-February-24, 15:17
Echognome, on Feb 24 2009, 04:11 PM, said:
I just had the following enlightening conversation with one of the urban legend spreaders who prompted this thread.
ULS: But I know it's better to leave a heater on than to turn it off and on again in a short period of time.
JSD: Of course it uses more energy to heat a cold room than to keep a hot room hot. But it does not use more energy to lighten a dark room than to keep a light room light.
ULS: Huh?
#13
Posted 2009-February-24, 15:25
#14
Posted 2009-February-24, 22:26
jdonn, on Feb 24 2009, 02:29 PM, said:
I suppose one needs to also determine to what energy you are referring. For, it takes a bit of personal energy to actually turn off the lightbulb.
First, you have the simple manual task of actually flipping the switch. Depending on the location of the lightbulb, you might also need to walk to the lightbulb. Those physical actions consume energy, which you must replace by consuming food. That food was grown, packaged, cooked, and consumed, all of which consumed energy that would not need to be replaced if you did not go about the added task of turning off the lightbulb. But, against that is the energy consumed doing whatever you would be doing instead of going about the task of turning out the lightbulb. Maybe that would have been spending ever-so-little extra time consuming beer. But, that slight increment might mean that you actually sleep longer when you get home. Or, you might have just enough extra to get drunk and forget to turn off the light when you pass out, which really throws everything off. There must be some minor impact on your likelihood of getting drunk enough to leave the lights on, and this should be considered.
Second, actually remembering to turn off the light consumes brain energy. That also must be fed, with all of the aforementioned costs. Moreover, by dedicating a portion of your thought processes to turning off lights when you leave, you may find that you forget other things, like protection for the evening festivities. Then, on that rare occasion where the alcohol does not lead to passing out at home but rather passing out in some strange person's home, and perhaps leaving their lights on, you might actually have the misfortune of adding to the carbon footprints of the community by addition of a screaming new consumer. This would be very bad, as these critters leave lights on all over the place, further consuming energy.
Third, by turning off the lights, you increase the likelihood that the screaming new consumers resulting from last generation's failed energy conservation efforts might find better cause to enter your abode while you are away at the aforementioned bar. The result of this, although not actually involving lights in your house at that moment, may be the incurring of many colored lights outside of your home, lights that are supplied with power generated by crusiers of our local finest. That light, and those bulbs, run off of the most inefficient of power sources, gasoline, and are undoubtedly much more costly than the initial light bulb and its energy consumption. All of this leads you, undoubtedly, to then leave your lights on even more than before, perhaps even with massive high-power lights that are triggered by motion occurring in your yard, which could be from benign sources like squirrels, raccoons, and the frolicking of the aforementioned screaming new consumers.
In light of all of this, my suggestion is to just leave the lights on.
-P.J. Painter.
#15
Posted 2009-February-25, 01:37
jdonn, on Feb 24 2009, 04:17 PM, said:
Echognome, on Feb 24 2009, 04:11 PM, said:
I just had the following enlightening conversation with one of the urban legend spreaders who prompted this thread.
ULS: But I know it's better to leave a heater on than to turn it off and on again in a short period of time.
JSD: Of course it uses more energy to heat a cold room than to keep a hot room hot. But it does not use more energy to lighten a dark room than to keep a light room light.
ULS: Huh?
hmmm
unless of course you're using the light bulb to heat the room
#16
Posted 2009-February-25, 01:45
kenrexford, on Feb 24 2009, 11:26 PM, said:
did you miss the XXth century? there is this device, called a CLAPPER.
and this...
Quote
...this is really bad.
#17
Posted 2009-February-25, 02:29
I only vote for using more energy...MUCH more energy compared to the option using less.
I vote Kenberg to honest count.
edit: side note
I vote for thinking of communication, broadband in all phases(BBO) as an unlimited resource. I resource where the monetary value is close to zero/free.
#18
Posted 2009-February-25, 05:31
jdonn, on Feb 24 2009, 10:17 PM, said:
This is more obviously wrong that the lightbulb UL. An electric heater needs one joule of electricity to provide one joule of heat. It is as simple as that. Moreover, the amount of energy required to keep a house T degrees warmer than the surroundings is proportional to T. But of course it could be that turning it off and on reduces its lifespan.
#19
Posted 2009-February-25, 05:36
helene_t, on Feb 25 2009, 06:31 AM, said:
jdonn, on Feb 24 2009, 10:17 PM, said:
This is more obviously wrong that the lightbulb UL. An electric heater needs one joule of electricity to provide one joule of heat. It is as simple as that. Moreover, the amount of energy required to keep a house T degrees warmer than the surroundings is proportional to T. But of course it could be that turning it off and on reduces its lifespan.
Yes, I think some are saying one joule of heat from a home heater unit requires more than one joule of energy. think about it.
#20
Posted 2009-February-25, 06:51
Whatever it cost you in more frequent replacement of light bulbs and extra personal energy consumed, you didn't want to know.
Oct 2006: Mission impossible
Soon: Mission illegal