From: Adam Scriven (scurvy_at_yahoo.com)
Date: 10/03/02
Message-ID: <20021003132327.68930.qmail@web9908.mail.yahoo.com> Date: Thu, 3 Oct 2002 06:23:27 -0700 (PDT) From: Adam Scriven <scurvy_at_yahoo.com> Subject: Re: Omega Garden - High-density gardening for small spaces/urban farming
--- c.knight_at_juno.com wrote:
> > > Light pipes are relatively easy to design.
> >
> > That is an awesome idea... and it brings to mind other things, like
> > a network of light tubes, that you can plug a new unit into when
you
> > get
>
> A while back someone designed a sulfur based light bulb that
> worked inside a microwave cavity -- supposed to be super efficient,
> but it put out SO much light that it would have been used only for
> commercial installations. They would put a tiny bulb at the end of
> a light pipe (made from 3M material -- a photomicrograph shows
> that it looks like a bunch of prisms, and it allows emission only out
> the "out" side of the tube) and then run a single pipe to the other
> end of the parking garage.
What kind of light spectrum did this light provide?
Was it like an HPS, suitable for using indoors for growing?
> Much like a fiber, the source of the light is irrelevant -- it
> matters only that it is coupled to the system, and then distributed.
[snippage]
> Fiber is the same basic principle as a light pipe. Ever seen a
> Sola-Tube? It's a type of skylight sold here in the States, with an
> output that looks very much like a circular light fixture on the
> ceiling.
Yup, I've seen those. THat was actually the thing I had in mind, but I
wasn't sure how flexible a system it could be.
With fibre you can go around corners and stuff (albeit not very sharp
ones yet), but I wasn't sure about the limitations for the larger
scale.
> Even on a cloudy day, in the shade, the sun is still a LOT brighter
> than that. On the off chance that we need more light, we could just
> use an optical concentrator -- think of it like a big magnifying
> glass, or satellite dish.
Yeah, so you have a huge collector on the roof, feeding into one tube
leading to your distribution node, or directly to where you need it.
Or as you mentioned below, heliostats (I'm not exactly sure what this
is, I'll do some searches on google), reflectors and that kind of
stuff.
> LOTS of choices. Engineering can be so much fun!
Absolutely!
> > What about combining the natural light tube with supplemental
> > artificial light?
>
> Why? Plants require darkness as much as they do light...they have
> different biological processes that happen at night. Other than just
> using it to balance out day and night into ~12 hour periods, I can't
> imagine requiring more light than is naturally available, especially
> with the easy availability of optical concentrators.
Well... not all plants need darkness all the time, and the ability to
control the light cycle indoors, even if it's only getting real
sunlight part of the time, would be very desirable. Some plants do
different things under different light regimes, so having them under
12/12 light isn't always desirable.
In fact, it is sometimes desirable to have plants under 24 hours of
strong light, so in that case some sort of supplemental light would be
necessary.
Mind you... you could always have collect both kinds of light with the
same system: some on the roof, connected together to collect the
natural sunlight, and another in the basement (or other place that can
be suitable controlled for heat, since lights do give off lots of heat)
that can source the artificial light. Join them all together as the
"source", but have the artificial light "source" be dark when it's not
needed, and on a timer (or have a light sensor on the roof, and when it
goes below a certain threshold it turns on the supplemental lighting.).
This would bring the added benefits that, with an indoor garden, you
wouldn't need to worry about cooling the grow area as much, because the
heat source for the lights could be anywhere. Would make it easier to
grow indoors in small areas.
I love thinking about this stuff... gets my juices flowing. :)
What's the feasibility of something like this? Does anyone have any
websites or books I could read about light tunnels?
One thing I've been wondering too, now that I'm thinking about
it...with fibre (and a Sola-Tube too, I would think), you'd only want
the light to come out the END... but if you were using as a source for
an Omega Garden you'd want it to radiate from the sides, for the entire
length of the garden only, to evenly distribute the light. Is this
kind of thing possible, perhaps with a change in materials, or a change
in covering?
If it were just a change in covering there probably wouldn't be any
losses, but if you had to have end pieces of different material,
wouldn't there also be losses transmitting between the two materials?
This probably wouldn't be a big deal for natural light, but it may be
for the artificial supplemental light?
Also, what about UV, would it be possible to convey that kind of light
too, as it too has it's uses in growing?
All these questions!
Adam
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