infra red filter

[salty joe]

Is there an IR filter that can be installed on a skylight on a temporary basis? I am going to light my reef with skylights and would like to use the sun's heat in the winter, but not in the summer. I googled infra red filter, but only got a zillion hits on photographic equipment.

 

[hahnmeister]

LoE filters UV as well as IR.

 

[salty joe]

Thanks, but based on the light coming through my windows, my guess is that LoE also would diminish PAR significantly. Also, if coral acclimated to very little UV were suddenly exposed to a higher level of UV, I'd expect problems.

I'm looking for a filter that is exclusive only for IR, if such a thing exists.

 

[Zimster]

an IR filter won't just reduce the amount of IR getting to your tank...but it can also reduce the amount of the visible spectrum that gets to your tank.

i did find something that will block all but visible light (mostly) and it is at:

http://www.anapro.com/english/product/product4.asp

they don't have the price listed so i assume its pretty spendy

here's another site i found:

http://www.photonics.com/content/spectra/2002/August/products/73801.aspx

 

[salty joe]

Thanks Zimster. That's a lot more than I could find. But yeah, it looks like they block a lot of visible light too. Which is my problem with LoE. I guess I'll look into how much better insulated a triple pane skylight is compared to double insulation. Thanks again.

Joe

 

[Zimster]

yup np

 

[dots]

Without fully understanding how IR radation effects corals and specific specie, the results could be detrimental.

Even though a large portion of the heat would be from IR, rather than filtering it out, changing the lighting parameters from one season to another, already effected by our nothern latitude and the suns change from summer to winter......

I would concentrate on more traditional means of cooling durring the summer like evaporative cooling, increasing your water volume, or chiller/AC useage.

 

[tatkinson]

Just an FYI, each pane of glass basically equals an R value increase of 1. Inert gasses and vacs between the panes help to increase that number, but marginally. Considering your attic may be insulated to R-45, the $$ for that additional pane (1 to 1.5 R Value) may be better spent on something fun for your tank. Also, Low-E coatings in general do serve to reflect IR radiation.

 

[salty joe]

Thanks tatkinson. Do you know where that kind of info can be found?

 

[tatkinson]

No Prob,

Where what info exactly can be found? Sorry, I sometimes miss the obvious. Just an aside, Low-E coatings do not inherently block light (at least noticeable to the eye, par values may be something else entirely) so if you are noticing a difference in light I would say the coating also has some tint as an adjunct.

-T-

 

[salty joe]

U valuae or R value comparing a single pane to a double pane to a triple pane. Also if you know where to find the optimum distance between panes. How much difference does argon make? Is it true that after 5 years or so the argon is gone?

I need to make these skylights as energy efficient as possible. The two of them will add up to 32 sq. ft. in a 75 sq. ft fishroom.

 

[tatkinson]

I don't know exactly where you would find the information other than construction books and the like, I'm sure it's out there on the interweb somewhere. Distance between panes is 1/4 to 3/4 max and 1/2 optimum (a little less for Krypton). Years ago 5 years on the Argon would have been optimistic and even today it is almost a certainty that the seal will degrade at some point and the gas charge will dissipate... but well beyond five years assuming a top quality product. Some of the gas can be absorbed by some of the desiccants used to mitigate moisture between panes but most quality manufacturers are using alternative desiccants that absorb little/less of the gas. This is one of those topics that the angle / supporting data is going to depend on who is trying to sell you what. Catastrophic loss only really occurs via catastrophic seal failure.
Real-world, gas fill with Low-E gives an additional .5 to 1 R for a total of three with Krypton being the better choice among the two. All manufacturers should be able to provide test results for their products but remember you are never going to actually see the numbers claimed (which will prob. be about R6 claimed). With that much glass make sure you get a really good HVAC guy and that he actually does the load calc. No matter what it's going to be tough to minimize wild temp swings, especially with all that glass above.

Have you considered going with solar tubes instead of traditional skylights. They def help minimize the heat loss/gain and are overall more efficient. Just some food for thought but something I would definitely take a look at.