solar panel

[salty]

I don't even think the word "majority" belongs in that statement. That makes the whole statement FALSE.

One of the major reasons that commercial lighting is almost all florescent s that it turns a higher percentage of energy into light. They give off a little heat, but not really very much. It counts, but heat from bodies down at ground level probably does a lot more to keep things warm. Heat rises. A single 100 watt incandescent bulb, or a human, gives off a lot more heat than a 4 tube florescent fixture with an electronic ballast.

Basically, I think you can scrap the Wikipedia article as a cite. It contains too many problems.

[gfretwell]

That is why I said "on a square foot basis".

[gfretwell]

That is why you really need to look at their energy bill. Every watt of power going in ends up being 3.4 BTU. I also question your "100w" bulb theory. A regular old F40 4' fluorescent tube uses 40 watts, not counting the ballast. Even the newest F032T8 electronic ballast system still consumes 130w or so for four 8' tubes. The real power hogs will generally be window and showcase lighting in each store since this will be selected by an interior designer more interested in how it looks than how much power it uses. You see lots of high wattage quartz and halogen lighting. Those ubiquitous track lights are mini suns

[salty]

To do a fair comparison, it would have to be a very similar sized structure located in the same climate.

It's not a normal building with 12 foot ceilings.

The scale matters!

[gfretwell]

Maybe but the argument starts to fall apart if their average watt per square foot is the same as other large malls. You would think there would be an economy of scale. I know a lot of buildings that do not need "heat" per se. The National Geographic building north of DC generates so much waste heat that they pump the excess into the lake out front and it has never frozen. This is with virtually zero solar gain. The glazing is about the same as most big office buildings. They are more interested in rejecting the sun to lower A/C bills in the summer.

[salty]

The question is not how much power it consumes. The question is how much of that power gets exhaled as heat, rather than as light.

The amount of light from 4 - 8' tubes compared to a single 100 watt incandescent? Surely you can see what is wrong with that picture!

[krw]

Once again, it DOESN'T MATTER if it's light or heat. Except what leaks out the windows, is turned to useful heat *very* quickly.

It doesn't matter! Watts is watts.

[gfretwell]

The reality is that every watt is exhaled as heat eventually. When I was designing computer rooms we used the total electrical input as the sensible heat number we needed to take away along with the latent heat of the people. Even the kinetic energy of motors eventually gets converted as heat through friction.

[salty]

It matters greatly. See if you can figure out why you are wrong.

Start with: A 130 watt florescent fixture puts out as much light as (insert number)____ incandescent 100 watt light bulbs.

And the light emitted does not magically turn into heat, either. Put your hand on a florescent tube and tell us how badly you are burned by all that light "turning into heat *very* quickly"

[salty]

If you were going to use the lighting as primary source of heating, I think it's pretty obvious that you would want incandescents, not florescents.

Light does not magically convert to heat. Light that is not reflected, is absorbed. Florescent fixtures give off very little heat compared to the number of incandescents needed to provode the same amount of light.

[krw]

It is you who is wrong, dog.

Doesn't matter. We're talking about the *HEAT* output. 100W is 100W.

WRONG!

Clueless.

[krw]

You want watts. Doesn't matter how you get them.

You are *wrong*. Everything turns to heat. Entropy.

...and heats.

Irrelevant. We were discussing the heat output of 100W light. It is, by definition, 100W.

[gfretwell]

When it is absorbed, it heats the surface that absorbs it. That is just a fact, unless you have repealed the conservation of energy laws. The reality is, there is very little energy in light compared to the heat, even the most efficient lights generate.

They do not select lights to heat buildings, that is just a byproduct of the inefficiency. If you lit your average office building to the foot candles we expect these days with incandescent, they would have to open some windows in the winter. Florescent were the norm by the time air conditioning was universal.

[trader4]

I'm still waiting for any credible reference that says the stores in the mall do not have their own heating systems. I gave you a couple that say they do in fact have their own heating systems. Besides your own personal claim that these are limited to just small spot heating, where's the proof?

I'm also waiting for an explanation of how this great energy savings through solar heating via sunlights in the common mall area in winter is not reversed in the summer with the need for more AC. In fact, given the typical cost disparity between NG and electricity, it would seem the entire economic gain could or more could be lost in summer.

And note, I'm not saying that passive solar can not be of benefit. I'm must skeptical of many claims put forward as sound environmental fact, when they are exagerated or don;t tell the whole story. Like the "electric car" being put forth as some perfect green solution, ignoring that the electricity still has to come from somewhere.

[trader4]

Good grief is dog confused. gfretw's point was that to compare the amount of heat put into a building from lighting you need to compare the electricity usage. That means the Kwh of energy going into the building. It makes very little difference if you use incandescents or florescents to generate heat. To generate the same amount of heat, sure, you'd need a lot more florescents. But if building A which uses florescents has 1000Kwh a day in usage for lighting, and building B using incandescents has 1000 Kwh a day in usage, they are both receiving almost the same amount of heat from it. There are some second order effects I can think of to consider, but they aren't going to be significant and would only further add to the confusion.

And I agree with gfretw that malls have a mix of lighting types.

[salty]

And clueless you shall remain.

Obviously a building using florescent lighting will use far, far, fewer watts than the same one lit by incandescent lights.

It is not even close.

It is the height of stupidity to compare a 130 watt florescent fixture to a 100 watt incandescent.

Like comparing an 18 wheeler to a pickup truck.

[salty]

I guess you'll just have to visit and see for yourself. Obviously nothing I say will convince you.

[salty]

Religious beliefs such as yours are not based on facts or logic.

HAND

[krw]

You're the one who doesn't believe in the Law of Conservation of Energy. Clueless is your name.

That was *not* what you said. You claim that light does not turn into heat, which is *false*.

Moving the goalposts after being proven wrong. That is your style.

[krw]

When cornered, a dog can only attack wildly.