SolaTubes for reef tanks - Page 23

barryhc · 12/01/2005, 08:59 AM

For a skylight applicaton, IF you are near a wall, two 4' x 8' sheets for "opposite walls" of mirrored acrylic could be curved in a nearly parabolic curve, from 4' wide at the top, to whatever tank width that you desire, with flat sheets at the sides, to make your "collector-amplifier". If you are 4' square wiyh the skylight, for instance, and run this into a 48" x 18" tank, you have captured 16' sq. ft. of light.

A 10" Sola Tube only delivers .55 sq. ft. per tube, so even if the skylight method was only half as effecient as the Sola Tube, 4 Sola Tubes offer a total of 2.2 sq. ft. of area, whereas the skylight version, even when rated at 50% would effectively deliver 8 sq. ft. of sunlight.

This mirrored acrylic sheet is readily available in 1/8" thick sheets, and is not that expensive. I think the relative effeciency would actually be better than 50%. It would require a bit of "boxing" in the rafters, but it wouldn't be that bad.

I just happened to have some of this for a diy hood I've been designing, and the skylight questions here got me to thinking.

Just some food for thought, this is a great thread by the way. Thanks for all the pictures Jim, and the best of luck, with corraling "Murphy".

> barryhc

Hef · 12/01/2005, 09:21 AM

Interesting thoughts. I've never heard of Mirrored Acrylic, I have worked with a lot of Mirrored Aluminum & Stainless. The Stainless is best, and this collector could be made with 1/32" thick material. I'm thinking a simple wooden frame could be constructed and a couple of screws would hold it in place.

Do you think you would need any type of special collector at the top, on the outside of the roof?

The numbers you are showing are staggering as far as amount of light that could be collected. I would like to hear others opinions on this.

Hef

barryhc · 12/01/2005, 11:51 AM

Hef, I have had a 4 x 8' sheet of it for several years, and it is just as reflective as your bathroom mirror.

The curves of the sheets would be inside the house, and it takes almost nothing but gravity to put these gradual bends into the acrylic sheet. The stuff that I bought is specificaly heat resistant for close proximity to the light hood design that got put on hold for a couple of years.

As far as collecting ouside the house goes, I think you might be better off without it, just to keep things maintanence free on the roof. The numbers should be pretty accurate, but I haven't tried it.

The large tank that I will be putting in soon is going to be in the basement, so I may not get the chance to try this myself any time soon.

Four times as much light as (4) 10" Sola tubes, is certianly a lot of light, and it may be more that you need to sheild some of it in the summer, more than trying to get more at the surface of the roof.

The 16 sq. ft. collection area is already taking care of this I would think. Just my two cents.

Happy Reef Keeping! > barryhc

salty joe · 12/01/2005, 01:24 PM

Barry,
That's a real interesting. I'm going to kick that one around a little bit.

Glad to see you on my other favorite thread. I love the direction this hobby is going.

Joe

Chihuahua6 · 12/03/2005, 04:39 PM

Hello again everyone. Sorry I haven't given an update but that's because nothing has changed. The 3 13" Suntunnels have been installed which I mentioned already. The hole for the inwall tank is done and trimmed out. I still need the tank! I will be placing my order soon but it will take up to 2 months to get it. You will hear from me as soon as the tank is here and running.

JMBoehling · 12/03/2005, 05:27 PM

Quote:

Originally posted by Chihuahua6
Hello again everyone. Sorry I haven't given an update but that's because nothing has changed. The 3 13" Suntunnels have been installed which I mentioned already. The hole for the inwall tank is done and trimmed out. I still need the tank! I will be placing my order soon but it will take up to 2 months to get it. You will hear from me as soon as the tank is here and running.

Thought you may have dropped the hobby and picked up something like GOLF instead

Look forwad to seeing your setup in the coming months.

Jim

Covey · 12/11/2005, 10:24 PM

Come guys updated pics!!

cwloo · 12/12/2005, 11:42 PM

Hi guys, nice tube there.

Just one question, will the newly introduce corals bleach b'cos the strong sunlight cause a light shock to them ?

gatohoser · 12/13/2005, 10:50 AM

I don't have a solatube but I would say the procedure is the same as for strong halides or any other strong light. You have to slowly bring them up to a spot where you want them from a darker area or else cover the tank with layers of a light reducing material like bird netting or whatever they use (have never gone that far with it but have seen it done) and slowly remove layers over a week or 2.

delnino · 12/13/2005, 11:34 PM

I could be a little off here but I would recommend against using mirrored acrylic for any light reflectors. I know that standard glass mirror is terrible for this purpose because it has a black backing that actually absorbs light. A room filled with mirrors appears very dark. A room painted white is very bright. Mirrors are designed to show an accurate reflection and I think the acrylic mirror is made for the same purpose. Polished aluminum, silver oxide coated aluminum, or even white metal will much better I think.

barryhc · 12/14/2005, 09:31 AM

Quote:

Originally posted by delnino
I could be a little off here but I would recommend against using mirrored acrylic for any light reflectors. I know that standard glass mirror is terrible for this purpose because it has a black backing that actually absorbs light. A room filled with mirrors appears very dark. A room painted white is very bright. Mirrors are designed to show an accurate reflection and I think the acrylic mirror is made for the same purpose. Polished aluminum, silver oxide coated aluminum, or even white metal will much better I think.

The light never gets to the "backing" because it is reflected from the mirror surface. ( and out of the "mirror filled room" for that matter )

Take a miirror and a white sheet of whatever, and lay them both flat outside on a bright sunny day. Now look into the mirror so that you can see the sun, try the same with the white sheet, if you can still figure out where it's at, and you are not on your way to the hospital.

Questions? > barryhc

hllywd · 12/15/2005, 03:43 PM

I wouldn't bet my life, but if I remember correctly delnino is right concerning the reflectivity of a mirror. The mylar over aluminum type materials are supposed to reflect much more light. The glass itself will absorb some light since it has to travel through the glass twice to go where you want it...

hllywd · 12/15/2005, 03:43 PM

I wouldn't bet my life, but if I remember correctly delnino is right concerning the reflectivity of a mirror. The mylar over aluminum type materials are supposed to reflect much more light. The glass itself will absorb some light since it has to travel through the glass twice to go where you want it...

gatohoser · 12/15/2005, 05:17 PM

I heard that too.

barryhc · 12/15/2005, 05:33 PM

Quote:

Originally posted by hllywd
I wouldn't bet my life, but if I remember correctly delnino is right concerning the reflectivity of a mirror. The mylar over aluminum type materials are supposed to reflect much more light. The glass itself will absorb some light since it has to travel through the glass twice to go where you want it...

I think you are getting confused about "dispersing" more light, and a white room will be very bright, in fact the brightest, by way of this "dispersion". Dispersion, however, is not what we are looking for when attempting to "direct" light to a "new location".

Also, the absorbtion of light through "mirror-grade-acrylic" is quite low.

Still, if this doesn't make any sense, then take the prospective materials outside on a sunny day, and look at the suns' reflection, and throw away the ones that don't blind you.

Did you ever notice how bright a white shirt looks under a "black light"? "Perception" is a "multi-edged" sword.

Happy Reef Keeping!!! > barryhc

barryhc · 12/15/2005, 08:06 PM

Quote:

Originally posted by hllywd
I wouldn't bet my life, but if I remember correctly delnino is right concerning the reflectivity of a mirror. The mylar over aluminum type materials are supposed to reflect much more light. The glass itself will absorb some light since it has to travel through the glass twice to go where you want it...

Good "mirror" is 97% reflective, so how much more reflective is 100%, or "perfect reflection"?

Are we making progress?

> barryhc

hllywd · 12/15/2005, 09:38 PM

Sorry guys I hate to beat this to death but I went back and looked at some of my info on glass mirrors, acrylic mirrors are a little better reflectivity-wise at about 85% where a good glass "plane" mirror is about 80% reflective. A front surface mirror such as a telescope primary or secondary mirror, depending on the coatings and enhancements, can be up to about 98% reflective. Specular aluminum is from about 85% reflective to the high 90%s. Painted steel can be greater than 85% and can be enhanced to over 90%.
The confusion of appearances arises because of the way the light is reflected. A plane mirror reflects the light rays parallel and looks bright, a concave mirror's reflection converges at a focal point and if large enough won't blind you but will set your head on fire when you look at it, a convex mirrors reflection is divergent and will appear less bright. Specular aluminum, and painted surfaces can and usually are more reflective than a "regular" mirror. The difference is the light rays scatter or are more difuse.
Tim

BTW I agree white wouldn't be the way to channel light into a space but neither is a "regular" or "plane" mirror unless you're talking about reflecting the light once. Everytime the light changes direction you'll lose intensity. At 80% that will add up fast.

barryhc · 12/15/2005, 09:52 PM

If we look at "transferrence" of light, it is going to stack up a little bit differently. Firstly I will concede to Hollywood's numbers. And we can get into fine detail on reflectivity, but the "look at the sun" analogy, is going to remain. This redirects, or transfers the light to an "aimed" new location. We can get into exact energy absorption, and therefore supposed effeciencies, by reading the temperature on the back of the surface, but any "mirror surface is going to put many factors of "more" light to the new location relative to the alternative material that is not as "blinding".

Have a great day!! > barryhc

hllywd · 12/15/2005, 10:24 PM

I think there are different ways of resolving this issue to our goal. The manufacturers of the tube skylights as far as I know all use some kind of specular aluminum, I installed a couple 14" Velux "tubes" this past fall that had flexible tubes much like a dryer vent only 14" dia with a shiny aluminum coating. I don't think these deserve consideration for our purposes because my instinct tells me the rigid tube would direct more light where it's desired. I think my 10" rigid Solatube is brighter than the 14" flexible Velux unit. I don't have a light meter but that's what my eyes tell me.
I think these have promise for reducing dependance on artificial lighting but unless a way to implement a larger skylight and get most of the light onto the tank area they will remain suplimental.

barryhc · 12/16/2005, 12:03 AM

Quote:

Originally posted by barryhc
For a skylight applicaton, IF you are near a wall, two 4' x 8' sheets for "opposite walls" of mirrored acrylic could be curved in a nearly parabolic curve, from 4' wide at the top, to whatever tank width that you desire, with flat sheets at the sides, to make your "collector-amplifier". If you are 4' square wiyh the skylight, for instance, and run this into a 48" x 18" tank, you have captured 16' sq. ft. of light.

A 10" Sola Tube only delivers .55 sq. ft. per tube, so even if the skylight method was only half as effecient as the Sola Tube, 4 Sola Tubes offer a total of 2.2 sq. ft. of area, whereas the skylight version, even when rated at 50% would effectively deliver 8 sq. ft. of sunlight.

This mirrored acrylic sheet is readily available in 1/8" thick sheets, and is not that expensive. I think the relative effeciency would actually be better than 50%. It would require a bit of "boxing" in the rafters, but it wouldn't be that bad.

> barryhc

Selfexplanatory

goby1 · 12/16/2005, 04:21 AM

Actually, a good front-surface mirror can be pretty much 100% reflective. As long as the material is reasonably pure, and the roughness is less than the wavelength of light you want to reflect, you're good to go. Of course, that would be cost prohibitive for the casual solar collector. Edmund optics has cheap parabolic mirrors, FYI.
G1

salty joe · 12/16/2005, 07:57 AM

If your skylight measures 4' x 4', and your aquarium measures 4' x 18", what is the advantage of curving the reflective material in the light tunnel versus running flat panels?

Joe

hllywd · 12/16/2005, 08:10 AM

The idea is to "focus" the light onto a spot the size of the tank.

salty joe · 12/16/2005, 09:18 AM

But the sun does not stay in a fixed position. It seems that the light would be focused at different points in different times of the day. Maybe I'm being really dense here, but I still can't see the advantage of curved panels versus flat tapering panels.

Trickman2 · 12/16/2005, 09:54 AM

When I finally get a house and not a condo. I plan on doing the solatubes for my tank.

12/01/2005, 08:59 AM	#551
barryhc Registered Member Join Date: Jun 2005 Location: Illinois Posts: 932	For a skylight applicaton, IF you are near a wall, two 4' x 8' sheets for "opposite walls" of mirrored acrylic could be curved in a nearly parabolic curve, from 4' wide at the top, to whatever tank width that you desire, with flat sheets at the sides, to make your "collector-amplifier". If you are 4' square wiyh the skylight, for instance, and run this into a 48" x 18" tank, you have captured 16' sq. ft. of light. A 10" Sola Tube only delivers .55 sq. ft. per tube, so even if the skylight method was only half as effecient as the Sola Tube, 4 Sola Tubes offer a total of 2.2 sq. ft. of area, whereas the skylight version, even when rated at 50% would effectively deliver 8 sq. ft. of sunlight. This mirrored acrylic sheet is readily available in 1/8" thick sheets, and is not that expensive. I think the relative effeciency would actually be better than 50%. It would require a bit of "boxing" in the rafters, but it wouldn't be that bad. I just happened to have some of this for a diy hood I've been designing, and the skylight questions here got me to thinking. Just some food for thought, this is a great thread by the way. Thanks for all the pictures Jim, and the best of luck, with corraling "Murphy". > barryhc __________________ The average person has only one breast, one testicle, and one brain. Most people who enter the reefkeeping hobby aren't average. Black and white don't exist, only "shades of gray"! Current Tank Info: 27gal. hex "plenum" +16 gal. "fuge"

12/01/2005, 11:51 AM	#553
barryhc Registered Member Join Date: Jun 2005 Location: Illinois Posts: 932	Hef, I have had a 4 x 8' sheet of it for several years, and it is just as reflective as your bathroom mirror. The curves of the sheets would be inside the house, and it takes almost nothing but gravity to put these gradual bends into the acrylic sheet. The stuff that I bought is specificaly heat resistant for close proximity to the light hood design that got put on hold for a couple of years. As far as collecting ouside the house goes, I think you might be better off without it, just to keep things maintanence free on the roof. The numbers should be pretty accurate, but I haven't tried it. The large tank that I will be putting in soon is going to be in the basement, so I may not get the chance to try this myself any time soon. Four times as much light as (4) 10" Sola tubes, is certianly a lot of light, and it may be more that you need to sheild some of it in the summer, more than trying to get more at the surface of the roof. The 16 sq. ft. collection area is already taking care of this I would think. Just my two cents. Happy Reef Keeping! > barryhc __________________ The average person has only one breast, one testicle, and one brain. Most people who enter the reefkeeping hobby aren't average. Black and white don't exist, only "shades of gray"! Current Tank Info: 27gal. hex "plenum" +16 gal. "fuge"

12/01/2005, 01:24 PM	#554
salty joe Registered Member Join Date: Oct 2002 Location: medina, ohio Posts: 2,419	Barry, That's a real interesting. I'm going to kick that one around a little bit. Glad to see you on my other favorite thread. I love the direction this hobby is going. Joe __________________ Time to roll the dice.

12/03/2005, 04:39 PM	#555
Chihuahua6 Premium Member Join Date: Jun 2004 Location: West Hempstead, NY Posts: 2,124	Hello again everyone. Sorry I haven't given an update but that's because nothing has changed. The 3 13" Suntunnels have been installed which I mentioned already. The hole for the inwall tank is done and trimmed out. I still need the tank! I will be placing my order soon but it will take up to 2 months to get it. You will hear from me as soon as the tank is here and running. __________________ Leah Amanda Current Tank Info: First salt tank 1985, current tank 150 g acrylic

12/15/2005, 03:43 PM	#562
hllywd Premier World Traveler Join Date: Nov 2000 Location: Ohio Posts: 4,293	I wouldn't bet my life, but if I remember correctly delnino is right concerning the reflectivity of a mirror. The mylar over aluminum type materials are supposed to reflect much more light. The glass itself will absorb some light since it has to travel through the glass twice to go where you want it... __________________ "The moment you doubt whether you can fly, you cease forever to be able to do it..." J.M. Barrie Current Tank Info: 210 AGA RR, Apex, 3x Kessil A360W & 2x 80W T5s, GEO 618 Ca Rx, BM220 CS2 skimmer, Tunze 6100s, 42" ETSS/AE Tech refugium/sump

12/01/2005, 09:21 AM	#552
Hef Premium Member Join Date: Feb 2002 Location: Fair Haven NJ Posts: 2,291	Interesting thoughts. I've never heard of Mirrored Acrylic, I have worked with a lot of Mirrored Aluminum & Stainless. The Stainless is best, and this collector could be made with 1/32" thick material. I'm thinking a simple wooden frame could be constructed and a couple of screws would hold it in place. Do you think you would need any type of special collector at the top, on the outside of the roof? The numbers you are showing are staggering as far as amount of light that could be collected. I would like to hear others opinions on this. Hef

12/11/2005, 10:24 PM	#557
Covey Registered Member Join Date: Jun 2005 Location: Davenport IA Posts: 2,018	Come guys updated pics!!

12/12/2005, 11:42 PM	#558
cwloo Registered Member Join Date: May 2004 Posts: 22	Hi guys, nice tube there. Just one question, will the newly introduce corals bleach b'cos the strong sunlight cause a light shock to them ?

12/13/2005, 10:50 AM	#559
gatohoser Registered Member Join Date: Sep 2003 Location: Monterey, CA Posts: 1,490	I don't have a solatube but I would say the procedure is the same as for strong halides or any other strong light. You have to slowly bring them up to a spot where you want them from a darker area or else cover the tank with layers of a light reducing material like bird netting or whatever they use (have never gone that far with it but have seen it done) and slowly remove layers over a week or 2.

12/13/2005, 11:34 PM	#560
delnino Registered Member Join Date: Mar 2004 Posts: 15	I could be a little off here but I would recommend against using mirrored acrylic for any light reflectors. I know that standard glass mirror is terrible for this purpose because it has a black backing that actually absorbs light. A room filled with mirrors appears very dark. A room painted white is very bright. Mirrors are designed to show an accurate reflection and I think the acrylic mirror is made for the same purpose. Polished aluminum, silver oxide coated aluminum, or even white metal will much better I think.

12/15/2005, 03:43 PM	#563
hllywd Premier World Traveler Join Date: Nov 2000 Location: Ohio Posts: 4,293	I wouldn't bet my life, but if I remember correctly delnino is right concerning the reflectivity of a mirror. The mylar over aluminum type materials are supposed to reflect much more light. The glass itself will absorb some light since it has to travel through the glass twice to go where you want it... __________________ "The moment you doubt whether you can fly, you cease forever to be able to do it..." J.M. Barrie Current Tank Info: 210 AGA RR, Apex, 3x Kessil A360W & 2x 80W T5s, GEO 618 Ca Rx, BM220 CS2 skimmer, Tunze 6100s, 42" ETSS/AE Tech refugium/sump

12/15/2005, 05:17 PM	#564
gatohoser Registered Member Join Date: Sep 2003 Location: Monterey, CA Posts: 1,490	I heard that too.

12/15/2005, 09:38 PM	#567
hllywd Premier World Traveler Join Date: Nov 2000 Location: Ohio Posts: 4,293	Sorry guys I hate to beat this to death but I went back and looked at some of my info on glass mirrors, acrylic mirrors are a little better reflectivity-wise at about 85% where a good glass "plane" mirror is about 80% reflective. A front surface mirror such as a telescope primary or secondary mirror, depending on the coatings and enhancements, can be up to about 98% reflective. Specular aluminum is from about 85% reflective to the high 90%s. Painted steel can be greater than 85% and can be enhanced to over 90%. The confusion of appearances arises because of the way the light is reflected. A plane mirror reflects the light rays parallel and looks bright, a concave mirror's reflection converges at a focal point and if large enough won't blind you but will set your head on fire when you look at it, a convex mirrors reflection is divergent and will appear less bright. Specular aluminum, and painted surfaces can and usually are more reflective than a "regular" mirror. The difference is the light rays scatter or are more difuse. Tim BTW I agree white wouldn't be the way to channel light into a space but neither is a "regular" or "plane" mirror unless you're talking about reflecting the light once. Everytime the light changes direction you'll lose intensity. At 80% that will add up fast. __________________ "The moment you doubt whether you can fly, you cease forever to be able to do it..." J.M. Barrie Current Tank Info: 210 AGA RR, Apex, 3x Kessil A360W & 2x 80W T5s, GEO 618 Ca Rx, BM220 CS2 skimmer, Tunze 6100s, 42" ETSS/AE Tech refugium/sump

12/15/2005, 09:52 PM	#568
barryhc Registered Member Join Date: Jun 2005 Location: Illinois Posts: 932	If we look at "transferrence" of light, it is going to stack up a little bit differently. Firstly I will concede to Hollywood's numbers. And we can get into fine detail on reflectivity, but the "look at the sun" analogy, is going to remain. This redirects, or transfers the light to an "aimed" new location. We can get into exact energy absorption, and therefore supposed effeciencies, by reading the temperature on the back of the surface, but any "mirror surface is going to put many factors of "more" light to the new location relative to the alternative material that is not as "blinding". Have a great day!! > barryhc __________________ The average person has only one breast, one testicle, and one brain. Most people who enter the reefkeeping hobby aren't average. Black and white don't exist, only "shades of gray"! Current Tank Info: 27gal. hex "plenum" +16 gal. "fuge"

12/15/2005, 10:24 PM	#569
hllywd Premier World Traveler Join Date: Nov 2000 Location: Ohio Posts: 4,293	I think there are different ways of resolving this issue to our goal. The manufacturers of the tube skylights as far as I know all use some kind of specular aluminum, I installed a couple 14" Velux "tubes" this past fall that had flexible tubes much like a dryer vent only 14" dia with a shiny aluminum coating. I don't think these deserve consideration for our purposes because my instinct tells me the rigid tube would direct more light where it's desired. I think my 10" rigid Solatube is brighter than the 14" flexible Velux unit. I don't have a light meter but that's what my eyes tell me. I think these have promise for reducing dependance on artificial lighting but unless a way to implement a larger skylight and get most of the light onto the tank area they will remain suplimental. __________________ "The moment you doubt whether you can fly, you cease forever to be able to do it..." J.M. Barrie Current Tank Info: 210 AGA RR, Apex, 3x Kessil A360W & 2x 80W T5s, GEO 618 Ca Rx, BM220 CS2 skimmer, Tunze 6100s, 42" ETSS/AE Tech refugium/sump

12/16/2005, 04:21 AM	#571
goby1 Premium Member Join Date: Feb 2004 Location: san francisco Posts: 364	Actually, a good front-surface mirror can be pretty much 100% reflective. As long as the material is reasonably pure, and the roughness is less than the wavelength of light you want to reflect, you're good to go. Of course, that would be cost prohibitive for the casual solar collector. Edmund optics has cheap parabolic mirrors, FYI. G1

12/16/2005, 07:57 AM	#572
salty joe Registered Member Join Date: Oct 2002 Location: medina, ohio Posts: 2,419	If your skylight measures 4' x 4', and your aquarium measures 4' x 18", what is the advantage of curving the reflective material in the light tunnel versus running flat panels? Joe __________________ Time to roll the dice.

12/16/2005, 08:10 AM	#573
hllywd Premier World Traveler Join Date: Nov 2000 Location: Ohio Posts: 4,293	The idea is to "focus" the light onto a spot the size of the tank. __________________ "The moment you doubt whether you can fly, you cease forever to be able to do it..." J.M. Barrie Current Tank Info: 210 AGA RR, Apex, 3x Kessil A360W & 2x 80W T5s, GEO 618 Ca Rx, BM220 CS2 skimmer, Tunze 6100s, 42" ETSS/AE Tech refugium/sump

12/16/2005, 09:18 AM	#574
salty joe Registered Member Join Date: Oct 2002 Location: medina, ohio Posts: 2,419	But the sun does not stay in a fixed position. It seems that the light would be focused at different points in different times of the day. Maybe I'm being really dense here, but I still can't see the advantage of curved panels versus flat tapering panels. __________________ Time to roll the dice.

12/16/2005, 09:54 AM	#575
Trickman2 Registered Member Join Date: Feb 2003 Location: San Diego Posts: 446	When I finally get a house and not a condo. I plan on doing the solatubes for my tank.