Energy Conservation
Does this blog have any physics/engineering types?
I have the following question: We are always being lectured to buy low energy appliances - fluorescent lights vs. incandescent lights and so forth. But what ever happened to conservation of energy, as a rule of physics rather than a pseudo-religious obligation? That is, suppose I use a "wasteful" incandescent bulb. Doesn't this "wasted" energy that isn't turned into light instead turned into heat. Assuming that it's winter, isn't that not waste at all since now I don't need as much energy to heat my house directly? I'm coming to the conclusion that as long as it's winter, it's impossible to "waste" energy by using the wrong appliances or light bulbs. Is there an error in this reasoning?
I have the following question: We are always being lectured to buy low energy appliances - fluorescent lights vs. incandescent lights and so forth. But what ever happened to conservation of energy, as a rule of physics rather than a pseudo-religious obligation? That is, suppose I use a "wasteful" incandescent bulb. Doesn't this "wasted" energy that isn't turned into light instead turned into heat. Assuming that it's winter, isn't that not waste at all since now I don't need as much energy to heat my house directly? I'm coming to the conclusion that as long as it's winter, it's impossible to "waste" energy by using the wrong appliances or light bulbs. Is there an error in this reasoning?
posted by Harsh Pencil | 1/15/2007 09:15:00 PM
My college major was Physics Engineering. But that was during my young, irresponsible years. (I was 17, had an apartment off-campus, and was out from under my father’s strict thumb.) So no actual expertise accompanies this explanation. It’s just my logical take.
95% of the energy going through incandescent light bulbs turns into heat. This is not a good thing in the summer, obviously. Nor is it a great idea for outdoor lighting. But even indoors during the winter, electric heat is two to three times more expensive to produce than gas, and the heat generated by the light bulbs is not pushed around via forced air, but hovers near the ceiling, so virtually none of it is actually enjoyed before it seeps out through the windowpane.
In short, use electricity via fluorescent bulbs to produce light, and more efficient gas heat, forced in near the floor where it can then rise, for heat.
I concede that Air Marshall knows more about hot air than I do. After all, I hear him dissimulate -- I mean, speak frequently, which is more than can be said about me.
I'll back up Scribbler (my education is in Electrical Engineering rather than physics). While it certainly possible to heat your home completely with incandescent bulbs, I wouldn't wanna be around when your wife opens the electric bill. It's a simple matter of using the right tool for the right job.
I guess using an analogy that you might related to better: I could certainly use that Federal paper with Ben Franklin's likeness to wallpaper my house, but traditional wallpaper might be more cost effective and easier to apply. It likely cleans up better too.
You might instead consider the Venezuelan bolivar, but I haven't done the math to figure out the cost effectiveness. No matter -just wait until Chavez nationalizes another industry, and we'll likely find that Venezuelan currency wallpaper is within reach economically.
I used to be a lighting engineer, perhaps I can help. Most modern commercial flourescent light fixtures are built to be part of the building's heating and cooling system. Air is ducted through the fixtures and the heat expelled in summer, or circulated in winter. Some computerized "building management systems" will turn on the lights at night rather than the furnace. These fixtures are more efficient in producing light than the compact flourescents you use in your house, but still less than 25% efficient. That means there isn't a lot of difference between incandescents and flourescents as "heaters." There is a huge difference-- between 3 and 5 TIMES the light per watt-- in what you buy the light bulbs to do, which is produce light.
The pseudo-science you should be concerned with is the notion that your motor-driven appliances should be energy efficient, although you have little choice anymore thanks to government regulation. The manufacturing of the additional material to make a small motor (like your washer, dryer, fan) more efficient consumes more energy than you will ever save using the appliance.
J. Ewing
The real "physics" answer of course is that it doesn't matter. All of the heat produced by the light bulb goes into the room, of course, but all of the energy that's turned into light ALSO gets absorbed in the room and turned into heat. The only difference is that with fluorescents, I'm using less total wattage to get the amount of light I need, and thus less total heating.
J. Ewing
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