what is the % of visable light to uv light coming from a tanning lamp? - Page 2

Don Smith · 04-24-2002, 06:04 PM

John:

As the "wattage" (or "voltage") increases, we do not increase the strength of any of the UVR "photons" (packets of energy); rather, what we do is to create more photons.

Although it is not quite the same, you can "visualize" this phenomenon by turning up the rheostat on your dining room ceiling light. As the "intensity" of the light increases (making it easier to see), the "change" is in the number of photons, not increasing the "strength" of the existing photons.

A 365 nm "photon" has a quantitatable "strength" that doesn't change as the power is increased. FYI, we "weight" a 280 - 302 nm "photon" 2000 times "heavier" ("stronger") than we do a 365 nm photon. That is because the 280 - 320 nm "photons" are more energetic and, thus, have more sunburning power.

What we must learn more about is the "tanning power" of our lamps which means that we have to "weight" the longer wavelengths "heavier" ("stronger") than they are in the EAS (erythemal action spectrum). This is what we have done with our TAS (tanning action spectrum) and what Wolff is looking at with their TAS.

Steve is correct when he says the best that can be done today is to use the MED/hour meter to evaluate the EAS and the A & B meter to "estimate" the TAS.

Hope this helps.

Don

PS: IMHO, Cosmedico is wrong! Their calculations "devalue" the efficiency of THEIR sunlamps! Does is make sense that we "lose" 60% of the output? If we did, our electrical costs would skyrocket!

Philips · 09-05-2002, 05:52 PM

In general flourescent lamps use power in the following %
37% heat radiated
20% heat in discharge
18% heat at electrodes

25% usable energy for conversion to UV

This is based on a 32 W T8 lamp.
So to answer your question in regard to tanning lamps, most of the energy is heat, then UV, then Visible light. The visible light can be eliminated with a woods glass filter (Black - light - Blue) but that is very expensive and also restricts some of the UV.

solarmeter · 09-05-2002, 06:54 PM

So... a whopping 75% "wasted" as heat. That's about what I've always heard too.

Lots of nasty mid-range IR? Too bad lumens and heat aren't (or can't be) measured in mW/cm^2 per nm or per selective bandwidth. Would be easier to comprehend.

None of this jives with prior post based on Optronics spectroradiometer. Maybe it goes out of range at higher bandwidths... or it's silicon detector isn't accurate up above UVR.

Don Smith · 09-05-2002, 08:30 PM

Steve/Phillips:

Sorry, but I'm not buying the numbers presented above.

If that much energy was given off as heat, you wouldn't be able to stand being in a tanning bed. In addition, if tanning lamps were that inefficient, we wouldn't be able to afford the electricity.

Go back and read my earlier post regarding our testing of a Cosmedico ESP sunlamp. We only had 0.25% in the near IR range and about 13% in the visible range. Is Phillips saying that ALL of this "heat" is coming in the mid and far IR range?

I don't buy the numbers. Sorry.

Don

solarmeter · 09-05-2002, 09:23 PM

At least please define the "37% heat radiated", because that should be able to be detected by SOME kind of radiometer. What wavelengths?

Can you post a test report showing all this in absolute quantifyable units?

Unfortunately, I believe it is true. "Efficiency" of HID/HP is probably even lower. I learned all that stuff a hundred years ago in physics class, but forgot most of it. I do remember efficiency of an internal combustion engine is really bad. Bring on fuel cells!

Brian Oshman · 09-06-2002, 11:33 PM

You would be suprised how much heat is developed. If you cut off the cooling system of the bed it would melt down pretty quickly. The top acrylic would zilch* onto the bottom acyrlic in several minutes.

*(anybody that took a lawn garbage bag, tied a knot in it, hung it off the ground, lit the knot on fire and heard the noise of the spiraling, molten plastic plummeting to the ground knows what a zilch is.)

Philips · 09-13-2002, 02:48 PM

In general flourescent lamps use power in the following %
37% heat radiated
20% heat in discharge
18% heat at electrodes

25% usable energy for conversion to UV

This is based on a 32 W T8 lamp.

This is based on a visible light lamp, probably what is in your ceiling right now. I do not have the energy diagrams for a tanning lamp. Since all Flourescent lamps are 254nm radiators it would stand to reason that it would be more efficent to closer 254 you get. However, for the lamp given these are real numbers. I do not have the spectral nm for the heat. I can send the diagram to any who want it.

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04-24-2002, 06:04 PM	#11 (permalink)
Don Smith Join Date: Feb 25 2000 Location: Tucson, AZ Posts: 1,578 Rep Power: 10	John: As the "wattage" (or "voltage") increases, we do not increase the strength of any of the UVR "photons" (packets of energy); rather, what we do is to create more photons. Although it is not quite the same, you can "visualize" this phenomenon by turning up the rheostat on your dining room ceiling light. As the "intensity" of the light increases (making it easier to see), the "change" is in the number of photons, not increasing the "strength" of the existing photons. A 365 nm "photon" has a quantitatable "strength" that doesn't change as the power is increased. FYI, we "weight" a 280 - 302 nm "photon" 2000 times "heavier" ("stronger") than we do a 365 nm photon. That is because the 280 - 320 nm "photons" are more energetic and, thus, have more sunburning power. What we must learn more about is the "tanning power" of our lamps which means that we have to "weight" the longer wavelengths "heavier" ("stronger") than they are in the EAS (erythemal action spectrum). This is what we have done with our TAS (tanning action spectrum) and what Wolff is looking at with their TAS. Steve is correct when he says the best that can be done today is to use the MED/hour meter to evaluate the EAS and the A & B meter to "estimate" the TAS. Hope this helps. Don PS: IMHO, Cosmedico is wrong! Their calculations "devalue" the efficiency of THEIR sunlamps! Does is make sense that we "lose" 60% of the output? If we did, our electrical costs would skyrocket!

09-05-2002, 05:52 PM	#12 (permalink)
Philips Join Date: Aug 16 2002 Location: Chicago IL Posts: 41 Rep Power: 0	In general flourescent lamps use power in the following % 37% heat radiated 20% heat in discharge 18% heat at electrodes 25% usable energy for conversion to UV This is based on a 32 W T8 lamp. So to answer your question in regard to tanning lamps, most of the energy is heat, then UV, then Visible light. The visible light can be eliminated with a woods glass filter (Black - light - Blue) but that is very expensive and also restricts some of the UV.

09-05-2002, 06:54 PM	#13 (permalink)
solarmeter Join Date: Nov 13 2001 Location: MI Posts: 534 Rep Power: 7	So... a whopping 75% "wasted" as heat. That's about what I've always heard too. Lots of nasty mid-range IR? Too bad lumens and heat aren't (or can't be) measured in mW/cm^2 per nm or per selective bandwidth. Would be easier to comprehend. None of this jives with prior post based on Optronics spectroradiometer. Maybe it goes out of range at higher bandwidths... or it's silicon detector isn't accurate up above UVR.

09-05-2002, 08:30 PM	#14 (permalink)
Don Smith Join Date: Feb 25 2000 Location: Tucson, AZ Posts: 1,578 Rep Power: 10	Steve/Phillips: Sorry, but I'm not buying the numbers presented above. If that much energy was given off as heat, you wouldn't be able to stand being in a tanning bed. In addition, if tanning lamps were that inefficient, we wouldn't be able to afford the electricity. Go back and read my earlier post regarding our testing of a Cosmedico ESP sunlamp. We only had 0.25% in the near IR range and about 13% in the visible range. Is Phillips saying that ALL of this "heat" is coming in the mid and far IR range? I don't buy the numbers. Sorry. Don

09-05-2002, 09:23 PM	#15 (permalink)
solarmeter Join Date: Nov 13 2001 Location: MI Posts: 534 Rep Power: 7	At least please define the "37% heat radiated", because that should be able to be detected by SOME kind of radiometer. What wavelengths? Can you post a test report showing all this in absolute quantifyable units? Unfortunately, I believe it is true. "Efficiency" of HID/HP is probably even lower. I learned all that stuff a hundred years ago in physics class, but forgot most of it. I do remember efficiency of an internal combustion engine is really bad. Bring on fuel cells!

09-06-2002, 11:33 PM	#16 (permalink)
Brian Oshman Brian Oshman Join Date: Apr 29 2001 Location: High Bridge, NJ Age: 39 Posts: 856 Rep Power: 12	You would be suprised how much heat is developed. If you cut off the cooling system of the bed it would melt down pretty quickly. The top acrylic would zilch* onto the bottom acyrlic in several minutes. *(anybody that took a lawn garbage bag, tied a knot in it, hung it off the ground, lit the knot on fire and heard the noise of the spiraling, molten plastic plummeting to the ground knows what a zilch is.)

09-13-2002, 02:48 PM	#17 (permalink)
Philips Join Date: Aug 16 2002 Location: Chicago IL Posts: 41 Rep Power: 0	In general flourescent lamps use power in the following % 37% heat radiated 20% heat in discharge 18% heat at electrodes 25% usable energy for conversion to UV This is based on a 32 W T8 lamp. This is based on a visible light lamp, probably what is in your ceiling right now. I do not have the energy diagrams for a tanning lamp. Since all Flourescent lamps are 254nm radiators it would stand to reason that it would be more efficent to closer 254 you get. However, for the lamp given these are real numbers. I do not have the spectral nm for the heat. I can send the diagram to any who want it.

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