Greenbuild Tradeshow - Phoenix

If you're in Phoenix this week, come by the Greenbuild trade show at the convention center.  I'll be in the EnOcean booth with the Illumra guys all day Wednesday helping to show the sustainable energy harvesting wireless technologies.  While not every installation makes sense for wireless equipment, many do, saving time, wiring, minimizing out-of-service time for hotels, commercial and/or residential energy management systems.

It looks like it's going to be a very busy show this year, with a lot of great events.  I'd love to stay an extra day and walk the show floor, as there are many amazing products being shown.

When less (energy) is more

Here's one risk to upgrading your lighting to higher efficiency fluorescent (or CFL, or LED): People don't worry as much about turning off the lights any more. See this blog posting for a comment from an actual user of a Cree LED fixture - "I don’t worry about turning them off all the time." I think it's a lot like the "sugar-free" syndrome. If you get a "sugar-free" or "low-calorie" food, I think people tend to eat more of it.
I think automated control systems help keep unused loads off any time they are not needed, but I'm rather biased, since that's what I design.

We need a fundamental shift in lighting

The title of this post may not mean what you think it means. At first, you may think I mean "we need to change all lights to LEDs," but in fact, it's really "we have to completely change how we build light fixtures before we can change all lights to LEDs."
The US Department of Energy has a contest going to award $10 million to the company that builds a 60-W lightbulb replacement using LEDs. There are several important stipulations that make this tricky, including dimmability using standard phase-cut wall dimmers, efficacy (luminous efficiency), color temperature and so on. Philips has produced the first entry, and certainly others are on the way.
The problem with this whole concept (while valid) is that everyone still seems to think that a lightbulb should look like the screw-in Edison base incandescent bulb. CFLs are the same way -- trying to fit a new technology into an old socket. Because of this, many CFL bulbs don't last very long because they get too hot in standard fixtures.
What we need to do is redesign the fixtures from the ground up. LEDs produce light and heat, and the heat they produce must be removed or the LED will fail quickly. The 20,000 hour (or longer) life of an LED presupposes that the LED is kept reasonably cool. Here's where the fundamental shift needs to happen.
Light bulbs, as a concept, need to be completely changed. Most luminaries (fixtures) are designed to take light from a point source (a light bulb) and spread that light evenly over a certain area. One notable exception is the linear fluorescent fixture. It takes light from a linear (long line) source and spreads it out. Take the same concept and apply it to LEDs, and we will be getting somewhere. Spread the LEDs out across the entire surface of the fixture, and the heat will be spread out and the light can still be focused nicely into the living/work space.
The "bulbs" can be individually replaced and certainly don't have to be replaced all at once. When one or two LEDs fail, the fixture can keep working (wire the LEDs in parallel, not series).
To make it even more fun, mount each LED on a metal-based circuit board (they are used a lot in high-power electronics) and include a small permanent magnet at each LED mounting location in the fixture, and now the LED elements are held in place magnetically. The electrical contacts can just be spring metal, and no real connector is required.
Part of the reason I'm posting this idea, rather than patenting it and keeping it to myself, is that now it can't be patented, because this is "prior art." I'd like many manufacturers to take the idea, build compatible fixtures and LED elements, and sell them to everyone.
If we want to accelerate the LED lighting revolution, I believe that a completely new paradigm is required.

Open Source Software Conference October 2009

I'm presenting two classes at the Utah Open Source Conference this year. I've had some ties to that group (and other open-source projects) for quite some time now. The cost is quite low, and as far as training goes, there are some great presentations on everything from virtual machines to advanced image editing with GIMP.

If you can make it, I highly recommend it. I'll be talking about securing your data over the internet with OpenVPN and filtering your home or office web traffic with Dansguardian and transparent proxying. There are some big names in the open source community presenting as well, including one guy who literally wrote the book on open-source telephony.

Nice to see more solid data on LED efficacy

Interesting blog post on one of the industry publication websites. They have some nice data on efficacy (power to light conversion efficiency) of several white LEDs used in light fixtures. Remember the efficiency numbers stated don't include power loss in the power conversion circuitry (in fluorescents, this circuitry is called the ballast) nor the losses due to the optical system (lenses, reflectors, etc). It's interesting anyway.

Zigbee, EnOcean, and Energy Harvesting

I won't take a lot of space for this one, as interest in this topic is probably narrower than what I usually discuss. This article about Zigbee vs. EnOcean in energy harvesting sensors for building management and energy savings presents some interesting points. Interestingly enough, illumra makes systems with both technologies, and even uses them together in a hybrid (or bridged) configuration. We use Zigbee for the backhaul, and EnOcean for the energy harvesting controls. As always, a disclaimer - I do work for/with illumra, so I'm not a completely objective third party relating to those products.

Expensive LEDs - why?

One contributing factor to the high cost of LEDs - they have to be kept relatively cool to preserve their long lifetimes. This means the "bulbs" require expensive metal heat sinks and ways to get the heat from the LED into the heat sink. There are lots of great innovations in this area, but it still adds a lot of cost.
A separate but related issue is that the efficacy (luminous efficiency) of the LED drops off when you turn the brightness up. There's a great article in the latest edition of the IEEE Spectrum magazine that starts from a nice high-level overview, then digs down to some very technical information.
What it boils down to is, we can have very bright LED lights, but they'll be less efficient than they could be, or very efficient LED lights, but they will be less bright (or more costly, assuming we just put more LEDs in each bulb/fixture).
Engineering is always about making the right tradeoffs - there's a lot of research going into LEDs right now, and over time we'll see the benefits.