
Transcend (YC S15) Launches an Extra-Efficient LED Light for Indoor Farmers - tlb
http://techcrunch.com/2015/07/08/yc-backed-transcend-launches-an-extra-efficient-led-light-for-indoor-farmers/
======
Animats
Why are those lights so big?

Indoor farms, especially in Japan, have been using LED lights for a while.
Red/blue combos, in the pink/purple range, seem to work best.[1] The big
advantage of LED lighting is not the reduced power consumption, but the
reduced heat. The lamps can be closer to the plants without cooking them,
which means the trays can be stacked closer and the density of the operation
goes up. For most non-druggie applications, the plants aren't that tall. So
small, distributed lighting units are used, instead of huge ceiling lamps.

Some plants can be overclocked. They do need a light/dark cycle, but it can be
shorter than 24 hours. The life cycle of the plant is then sped up.

[1] [http://www.economist.com/news/science-and-
technology/2160219...](http://www.economist.com/news/science-and-
technology/21602194-indoor-farming-may-be-taking-root-light-fantastic)

~~~
TranscendL
I'm Brian, the founder of Transcend.

Each light is 19 pounds and is about 10"x8".

There are two reasons the light is the size that it is. First temperature. We
have a passive heat sink with fins and a plastic remote phosphor sheet. Both
have to stay relatively cool and more surface area makes this possible.

Its funny, the first fixture we built and sampled to growers was about 25x
smaller. We used an active heat sink and a glass phosphor sheet. A common
complaint was "why is this so small?" I want my lights to be "big and strong".
We took this feedback and decided to move to passive design.

Our original logic was that smaller is better, especially in a greenhouse. The
most efficient light is one that is off and the less shading of sunlight the
better.

~~~
mabbo
Thanks for coming here to reply to comments!

I think small lights could be a really good market for you, for all the
urbanites like me, living in condos. Make a tiny kit that can grow herbs or
lettuce at an accelerated rate using little power because of LEDs, and I'd buy
it in a second.

As it stands, I think a 1m strand of TL-RL20 will be a purchase for me soon,
and I'll build the kit myself.

------
Zak
_Trancend’s bulbs differ from typical LED lights because they only use blue
light. The company has developed a wavelength conversion system that uses
phosphorous to convert blue photons, which are the most efficient type of
photon, into any other color photon._

Typical LEDs used for illumination are blue LEDs with a phosphor coating to
produce white. Transcend is doing essentially the same thing, but the goal is
to produce wavelengths optimal for plant growth instead of a broad spectrum
for illumination. The biggest difference in implementation looks to be that
Transcend is separating the phosphor from the emitter while most LEDs used for
illumination bond the phosphor directly to the emitter.

------
Theodores
There are a lot of vegetables and fruits that I do not buy due to the air
miles. For instance those nice peas in pods from Kenya. Those things don't get
here (the UK) by boat whereas bananas from the Caribbean do get here by boat.
Boat is acceptable to me, good for trade and enough arrives by boat for a
decent meal to be made.

In theory these lights change everything, why grow peas in Kenya, put them on
a plane and send them 1/4 the way around the world when a greenhouse in the
Home Counties will do nicely?

The cannabis angle is pretty good too. As things stand growing those plants
takes a stupendous amount of energy with all the problems of ventilation,
mould growth, noise from the ventilation and the need to 'not get caught'.
With this technology those that can hold down a job can get growing their own
without having to have the huge 'leccy bill or having to be friends with
dealers.

I like the lateral thinking of tuning the light to suit photosynthesis by
using phosphors, I am surprised that has not been possible before. One day
this will seem so obvious yet it wasn't until this product came along.

~~~
ars
You have got to be kidding.

You are worried about air miles, but are willing to accept artificial light?

Do you just want to feel like you are being environmentally friendly, or do
you actually want to be environmentally friendly?

I've been surprised at how many people only want to feel that way, but don't
actually care about being environmentally friendly. (A good example of this is
locavores.)

> of tuning the light to suit photosynthesis by using phosphors, I am
> surprised that has not been possible before.

It has been thought of before, people have been doing it for decades. This is
just an incremental improvement.

~~~
oldmanjay
Is it your contention that LED lighting uses as much energy as flight?

~~~
ars
Comparing light to grow plant, vs fuel to fly the fruits of that plant?

LED lighting use more, even without doing the calculations I feel quite
confidant in saying that it uses much more.

~~~
fineman
Wrong. There are distance and repetition factors you are failing to consider.

With a single trip 100m trip, the LEDs lose. With 10^7 100km trips, the LEDs
win. The question is where the line is, and the answer is that it's going down
all the time.

~~~
ars
> With 10^7 100km trips, the LEDs win.

Hu? You are planning on shipping a single tomato 621 million miles? That's
enough to ship it to Mars and then back.

Why in the world would you do that? Wouldn't it spoil?

You know you have to pay to power the LED, right? It's not just equipment
cost? It takes less energy to grow a tomato in the sun, then fly it somewhere
then it does it grow it indoors with artificial light.

And no, LED efficiency is not going up all that much anymore - there are
physical limits to that.

~~~
fineman
Yes, I'd still grow _just one single tomato_ and send it on many millions of
trips. I'll call it "travel-with-my-tomato.com" (Overnight charges may apply
for trips to mars.) /s

~~~
ars
So if your whole post about 10^7 100km trips was a joke, why did you post it?

~~~
fineman
Your point was that LEDs don't break even. My point is that there's a
threshold at which they would.

If you only ever grew one tomato then you probably could buy a cheap plane
ticket to deliver it, for less than the lights. So you'd be right, the LEDs
would use more energy (cost to make, ship, and use) vs the delivery charges
for the sun-grown (free energy) tomato from farther away - even if shipped
expensively.

But if you grew millions of tomatoes from the same LEDs then you'd be wrong -
now buying the grow lights is much more efficient than shipping in sun-grown
tomatoes from even a few kilometers away.

How many tomatoes are you going to grow?

~~~
ars
Is there some reason you keep ignoring the power it takes to run the lights?
It take FAR more power for the lights than it does for the airplane.

You keep focusing on _buying_ the lights, but I'm not talking about that. I'm
talking about _running_ the lights.

------
nkurz
The descriptions on Transcend's website make me feel uneasy. I presume they
have a solid product, but it feels like it's being oversold.

 _Each of our remote phosphor fixtures are rated to last for 96,000 hours to
90% output. That 's over 10 years of 24/7 use. _

How has this been tested? And if it is true, why is there a 5 year warranty
rather than a 10 year? And what level of decline in output is covered by the 5
year warranty?

 _Efficiency: >2.0 μmoles per watt_

Presuming you mean "per joule" rather than "per watt", this is very close to
the claimed efficiency of the underlying Royal Blue LED, and (I think) much
higher than any white LED. While I can believe there is some benefit from the
lower temperature of the remote phosphor, this would be a remarkably high
number for a full spectrum light. How has this been measured?

~~~
TranscendL
Yes, it has been tested. The industry standar LM-80 lifetime testing of the
LED shows an L70 lifetime of ~300,000 hours. We are operating the LEDs at a
lower temperature meaning they should theoretically last even longer. This is
how we specify the 96,000 hour operating time to 90%

The Royal Blue LEDs we use have a ~55% EQE (external quantum efficiency). This
gives a μmoles per joule a fair amount above 2.0. We lose a few photons during
the conversion process and that drops us down to about 2.0.

We have a ~30% efficiency improvement over standard white LEDs because the
phosphor is remote. The gain is 100% due to to the recycling cavity and
omnidirectional nature of phosphors.

~~~
nkurz
I'm still surprised at the level of efficiency, but glad to hear that you can
back it up. I wasn't doubting that an underdriven LED would last that long,
rather I was surprised that the remote phosphors would last that long without
decrease in output. But reading more elsewhere, I now see that the lifespan of
the remote phosphors can be excellent:
[http://www.digikey.com/en/articles/techzone/2014/apr/develop...](http://www.digikey.com/en/articles/techzone/2014/apr/developing-
a-standard-test-for-remote-phosphor-lifetime-and-color-maintenance)

For others who are interested, here's another interesting link on the remote
phosphor approach:

[http://www.ledsmagazine.com/articles/print/volume-9/issue-7/...](http://www.ledsmagazine.com/articles/print/volume-9/issue-7/features/fair-
comparison-of-white-leds-and-remote-phosphor-guides-design-choice-
magazine.html)

And a nice overview of the efficiencies of white LED's, and where the losses
usually are:
[http://www.sandia.gov/~jytsao/SSL_Trajectories_Proc_IEEE.pdf](http://www.sandia.gov/~jytsao/SSL_Trajectories_Proc_IEEE.pdf)

The exact figure in the last are already somewhat out of date, but if you plug
in the specs for the newer LED's, presumably the underlying physics hasn't
changed.

------
technotony
Congratulations on launching! We were in a previous YC batch (glowing plant,
S14) and grow lots of plants indoors. We are interested in lighting systems
which promote early flowering, as this shortens our product development cycle.
Can your lights be set to encourage this (ie can you balance vegetative growth
vs flowering?)

~~~
TranscendL
Thanks!

It is possible. We are coming out with a new LED T5 lamp where we can easily
customize the output spectrum. It would be fun to work together to find out
the ideal spectrum.

------
logfromblammo
" _...blue photons, which are the most efficient type of photon..._ "

Argh.

Plants require light at 450 nm (blue) and light at 650 nm (red) to experience
normal growth, and 730 nm (far-red) is also required to flower normally. (That
last one may be important to growers of _certain plants valued for their
flowers and /or fruits_.)

Phytochromes and photropins are the plant pigment-hormones that govern the
plant life cycle. They respond to those 3 critical wavelengths of light to
allow the plant to guess the time of day and the season of the year. Some
plants also need a dark phase to "sleep", but it doesn't have to be as long as
an actual night.

Blue light is likely most efficient _at forcing the increase in green plant
mass_. That is, it makes bigger leaves and longer stems. That isn't always
what you want for indoor farming.

The ideal indoor grow light would have a programmable, timed output of those
three critical wavelengths of light, with a different ideal program for each
type of plant. You may wish to start with red light, to germinate the seeds,
go to blue light for rapid growth, then manipulate the plant into flowering
out of season by switching between the two reds.

Transcend also needs a smaller, programmable 650/730nm light to offer a
complete indoor farming solution, particularly for plants that do not get
natural sunlight. It wouldn't need to use nearly as much energy, as it is
being used primarily for hormonal signaling rather than photosynthesis.

~~~
deckar01
Most efficient to produce not most efficient for plant growth.

Context: "The company has developed a wavelength conversion system that uses
phosphorous to convert blue photons, which are the most efficient type of
photon, into any other color photon."

~~~
logfromblammo
If you're using phosphors, you do want to make blue or UV. It's far easier to
step a photon down in energy than to absorb multiple lower energy photons and
emit one at higher energy.

But the highest efficiency color for LEDs to produce largely depends on what
Cree and Nichia are doing this year. Unfortunately, most of the readily
available numbers tout luminous efficiency rather than raw light power. That's
fine if you're looking for a reading light, but chlorophyll does not have the
same absorption spectrum as the opsins in the human eye. You have to look for
"wall-plug efficiency", which is less commonly reported.

So with respect to photons emitted per watt, I'm not sure which LED chemistry
takes the prize. It depends on the temperature and input power, too. You can
achieve 200% wall-plug efficiency, but only if you're converting picowatts of
electricity into picowatts of photons in a hot LED. This is not possible
(economically) for grow lights.

The benchmark for grow lights is the low-pressure sodium lamp, at about 38%
efficiency. LEDs maybe get 30-65%, considering transformers, internal
resistance, quantum efficiency, reflective losses at the die-capsule
interface, etc. Higher efficiency comes from more expensive components.

As for chemistry, InGaN efficiency drops at longer wavelengths, and AlInGaP
efficiency drops at shorter wavelengths, leaving a big efficiency trough in
the green range. (Fortunately for this, plants don't need green.) I suspect
that AlInGaP LEDs in the orange range are more efficient than visible blue
InGaN LEDs, but this is hard to show with a lazy web search.

So when you say "most efficient" you really have to be _very explicit_ about
the application. That was my implied complaint about that sentence in the
article.

------
bastijn
Interesting, philips (nl) launched the exact same somewhere last week.
[http://www.lighting.philips.nl/application_areas/horticultur...](http://www.lighting.philips.nl/application_areas/horticultural/cityfarming.wpd)
sorry for the Dutch link, you can switch at the top to English.

------
wnkrshm
Don't you lose a lot of usable energy by not having any optics to shape the
radiation? The phosphor surfaces will just diffusely glow. Of course, with an
emitting area that big, you also need huge optics to control it properly

~~~
TranscendL
Phosphors are interesting in that they emit in 360 degrees. We have a
"recycling cavity" behind the phosphor plates that reflects "backward"
emitting photons. The design of this cavity is key to an efficient remote
phosphor system.

As far as forward throw, the plate is a lambertian emitter. This means ~80% of
the light is in a 60 degree beam angle and nearly >95% within 70 degrees.

~~~
wnkrshm
If you already have a light-recycling setup for the phosphor - maybe you could
additionally use brightness-enhancement films to use for light recycling in
angular space. Just like in liquid crystal screens, BEFs could refract light
rays with high exit angles back towards the phosphor, giving you a collimation
of about 45° for rectangular, linear prism films.

But of course, conservation of optical étendue ('optical entropy' so to say)
can't be cheated and absorption and scattering losses will be the trade-off
for better collimation.

~~~
TranscendL
That's a great idea.

Etendue shouldn't be too much of a concern because we are emitting onto a
relatively large space. We hadn't considered using a BEF but will certainly
look into it.

Someone else mentioned using a holographic printed film for the same purpose
of a BEF. Have you every used something like this?

~~~
wnkrshm
Not personally - I've read about holographic films but they were rather for
screen backlighting - you won't need that precision, I think. There are some
advanced materials that are basically very advanced diffusers with a defined
scattering distribution.

But BEFs are dirt cheap and do a very good job for this, your run-of the mill
backlighting setup for screens is a very simple, effective system. Also: Using
two linear BEFs (rotated relative to each other at a right angle) is more
efficient than one pyramidal film.

The losses I mentioned are because of the light-recycling: You get lots more
back reflections into the system - every ray that doesn't have the right exit
angle gets reflected/refracted back into the system, the phosphor will
absorb/re-emit/scatter, randomizing the ray's direction again and the ray
'retries' to get out of the system with a different angle.

These processes naturally induce losses (non-radiative decay in the phosphor,
Fresnel losses at one of the BEFs, no perfect reflection on the back mirror).
Even if you only lose a fraction of a percent, you lose that fraction lots of
times before a ray may make it out of the system. It adds up - still, the
collimation is very good for such a simple system (i.e. slap two films for a
few dollars per sqm over your emitting area) it should be very easy to test.

Edit: You'll get the best collimation for 90°-angle prism films - there are
other BEF types that'll smooth the angular distribution of the light recycling
for wide viewing-angle displays.

------
ernestipark
If you're interested in indoor growing, Grove Labs is building an entire home
aquaponics appliance. [https://grovelabs.io/](https://grovelabs.io/)

------
roel_v
The rope lights are especially cool for indoor hydro pole installations.
Still, $1000 + 1$/day in electricity, it could grow let's say 100 kg of
strawberries / year with that much light (that's an optimistic estimate),
which would cost say 500$ to buy in a supermarket. That's not counting the
cost of the rest of the installation, fertilizer etc. Could make sense at huge
scale, but not for home sized installations, I think.

~~~
jws
Yeah, the numbers are funny. They claim they will pay for themselves in energy
savings in a year, but that seems to be against some unnamed alternative in
their "up to 70% more efficient" claim.

High pressure sodium lamps (apparently the norm for indoor commercial food
growing) look to be about 1.8µmoles/watt, compared against the ">2
µmoles/watt" of these lights, well, its going to take a long time to save
$1000 in energy on a 250 watt lamp.

Lamp lifetime may tip the scales in favor of these LED lamps. Lamp size may
also help, I used a 600 watt high pressure sodium lamp in my calculation
against the 250 watt LED.

(µmoles are new units to me. I think I got through the lumens-lux-µmoles
calculation correctly, but maybe not.)

~~~
TranscendL
The numbers are heavily influenced by cost of electricity and time of use.
Payback ranges from 1-5 years with an average user seeing payback in about 3.

Average 600W HPS lamps are 1.0-1.3 µmoles/watt. A complete fixture consumes
660 watts with ballast losses. They generally lose about 20% of their light
due to reflectors (omni-directional lamp in a directional application).

This means that our 2.0 µmoles/watt fixture at 230 watt consumption can
replace a 660 watt HPS fixture, provide the same amount of light, and have a
nice payback.

~~~
roel_v
Here's what I didn't get from your website: there are typically two
wavelengths you're interested in for growing plants, depending on the
phenological stage: a red and a blue (I can't remember the exact numbers, but
the band is quite narrow). How can it be that your lamps have higher
efficiency despite providing a complete spectrum? I don't know anything about
light physics, hence my question; intuitively, I'd say you could have higher
'yield' by focusing all energy you put in to one wavelength (or at least, a
narrow band).

~~~
TranscendL
It turns out that plants use more than just red/blue for photosynthesis. They
do indeed absorb narrow bands of red/blue more strongly than other colors like
green (this is why plants are green) but only absorb about 10% more
efficiently.

The green light not absorbed is reflected. This gives the opportunity for
green photons to reflect their way down to the bottom leaves for a more
distributed growth.

We have built a number of lights with "focused" spectrum but haven't seen a
benefit. In many plants, like "red" lettuces the leaves only turn red with a
full spectrum (I have no idea why, a botanist might know the answer...)

We do see a benefit to skew the spectrum for many flowering/fruiting plants in
later growth cycles and have a plan to come out with a "fruiting spectrum" in
the future. This will part of our August Indiegogo campaign.

~~~
roel_v
Interesting. I do admit that much of what I know comes from books written for
growing marijuana, since until a few years ago those were almost the only
(large scale) applications of indoor growing, and that most of that knowledge
isn't very scientific (for example until a few years ago the mainstream
technique to force bloom on mj plants was to vary the light cycle only).
Research is frantic in the field, a fascinating development.

One last question if you don't mind: do you see a market for this in small
scale operations, or do market pressures force your customers to grow always
bigger like in the rest of agriculture? It seems that the only (sustainable)
way to make a profit on growing food (plants and animals) is by scaling up.

(OK I lied, I have another question actually: with the pressure on lighting
system vendors in Europe to screen their customers for illegal operations, and
increasing pressure to hold vendors accountable for such use, are you
experiencing that American vendors actually have a market advantage on this?
Do you export to Europe? (meta: who would have thought just 10 years ago that
in 2015 the US would become the world's leader on high tech marijuana
production!) also sorry for focusing on mj, your industry suffers from its
association with it, I know - it's just that that market was the only non-
academic source of knowledge on it for so long)

~~~
TranscendL
It will be interesting to see how the market scales. There are certainly
advantages to large commercial greenhouses etc... but there is a quickly
growing trend for small local producers that grow a few hundred or couple
thousands plants at a time. They might service a grocery or a few restaurants.
There is also a trend for people to grow at home, grove labs was already
mentioned in this thread as an example. My guess, ultra-efficient, nearly
fully automated indoor production facilities will be a major player. Labor and
energy are the two biggest costs to production and there are emerging
technologies to address both of these.

Regarding Europe, it hasn't been a primary focus for us but we have exported a
few orders to the UK, Germany and Netherlands. I hadn't heard of pressure on
vendors to screen their customers. I'll have to look into this.

Our orders so far have split about 50:50 between veggies and marijuana. The
marijuana side of the business does certainly seem to overshadow the veggie
side as far as general public interest goes!

~~~
roel_v
Thanks for your answers, and best of luck with your business.

------
Someone1234
It doesn't matter so much now with legalisation, but I cannot help but wonder
what impact these high efficiency LED lights would have had on the illegal
weed business. A lot of police forces did things like use infrared cameras and
electricity usage to find people growing such things, but with these LEDs they
could remain more undetected for longer.

But on a more broad note: Indoor farming has real potential, in particular for
certain types of crops. Not only do indoor farms use less water (which takes
energy to produce and transport), but requires less or no pesticides, can be
grown out of season, and you're less subject of good/bad weather patterns.

I don't think we'll see this type of thing for inexpensive crops that use up a
lot of land (e.g. corn) but we might be more expensive crops that are fairly
land efficient (e.g. nuts, fruits, etc).

~~~
Turing_Machine
A guy is setting up a large-scale LED vegetable farm in Alaska, where getting
fresh produce in the winter is quite expensive, since of course it has to be
shipped in by a fairly fast (= costly) method. See:

[http://www.adn.com/article/20150315/vertical-farm-poised-
ris...](http://www.adn.com/article/20150315/vertical-farm-poised-rise-inside-
old-mat-maid-building)

------
themgt
Interesting tech, but quite expensive. I'm looking to do some indoor
herbs/greens in my office, but these lights look maybe 5x more expensive than
the multi-color diode competitors.

I'd be curious to see comparison with PAR spectrum and plant grow results
against similar wattage multi-color LED.

~~~
roel_v
But their claim is 5x longer lifespan, too. And where do you buy 250w led grow
lights for 200$?

~~~
themgt
Here's a 300w for $135: [http://www.amazon.com/GalaxyhydroTM-Spectrum-
Greenhouse-Flow...](http://www.amazon.com/GalaxyhydroTM-Spectrum-Greenhouse-
Flowering-Growing/dp/B00INM0750/)

Or a 1200w for $369: [http://www.amazon.com/KingTM-Spectrum-360-860nm-10bands-
Flow...](http://www.amazon.com/KingTM-Spectrum-360-860nm-10bands-
Flower/dp/B00WHF830K/)

I actually have free electricity at my office, otherwise I'd run the numbers
to see the cost savings. 5x longer lifespan ... I'd want an independent
review.

~~~
roel_v
Oh wow those are very good prices. If they perform well (or even half of what
they promise), then yes these will give the upmarkets ones a run for their
money. Of course the same can be said for almost all goods. I'd love to have
time to experiment with an indoor aquaponics garden in my basement, and try
out various lights.

------
eonw
considering that not all plants need the same spectrums throughout growth, i
wonder if they have any plans to allow tuning of such things. if you are
trying to grow the best, energy efficiency doesn't matter as much as top
quality product at any cost. I think heliospectra lights allows you to change
their output via an open API.

with the legalization of marijuana already happening in some states and
pending in many others, the lighting industry is full of fluff right now and
too many players... will be interesting to see who stands, who falls and who
M&A. I think many growers will stick to HIDs until someone can prove LEDs,
Plasma or induction not only delivery the same quality product, but can
actually do it cycle after cycle, these 50k hour guarantees are suspicious at
best.

~~~
TranscendL
We don't have spectral tuning functionality at the moment but it's something
we are working on. A number of customers growing fruiting/flowering plants
have asked for this sort of spectral control. For non-fruiting plants there
seems to be less of a demand. We plan on having a next gen remote phosphor
design with spectral control within the next 12 months.

~~~
eonw
thanks for your response.

i would imagine spectral controls to be less useful for leafy greens. will the
spectral controls be remote controllable? ie; an api over some type of wifi
connection?

------
drfritznunkie
I've been spending some time myself designing remote phosphor lighting and I'm
wondering if they've really developed a new remote phosphor technology, or if
they're sourcing a custom phosphor blend and substrate from someone like
Intematix.

Also curious if they're using a film (like WhiteOptics White97) or having the
cavities coated (I forget the product name). None of the coatings were cheap
when I was researching them, but a % or two better than the films.

I'd love see the LED driver board on these...

But anyhow:

It's incredibly cool stuff, especially when you show someone the raw blue leds
(blindingly bright), then drop a remote phosphor over it.

Kudos for going for it, and good luck. I wish I had your fortitude!

~~~
TranscendL
We build our own remote phosphor components and in some cases source
components from companies like Intematix. We have a solid "side business"
where we formulate and produce custom remote phosphor components for non
general lighting applications.

For the recycling cavity we do indeed use WhiteOptics. We used Furakawa in our
last design and have had success with both.

