Friday, October 17, 2008

When "green" isn't

I recently attended (and presented at) an open source conference. One of the presentations was fascinating, covering all kinds of automation devices for home lighting, security, and automation. The presentation is here:

http://2008.utosc.com/presentation/51/

He uses Control4 wall-mounted dimmers to control the lights throughout his house, and motion detectors dim the lights on (gently) when you walk into a room or down a hall. The part I found fascinating, however, is that if you try to use his system to save energy, there isn't too much to be saved, because each wall box dimmer consumes a few watts of power, even when off. With a house full of these, that could be over 100 watts of standby power, added to whatever the central controller requires (maybe a few hundred watts if it's a PC). This means that you're burning between 3 and 10 kWh every day just to run the automation systems. He specifically pointed this out during the presentation so we would not try to save energy by burning just as much energy.

Referring back to the system in my kitchen that I described in my first post, since I'm using older generation Watt Stoppers, only one of them is drawing power, and it provides the DC supply to the illumra room controller and the other relays. If all the Watt Stoppers were powered by 120VAC, there would be a lot more standby power being used. I think it's only 2 or 3 watts, so it would probably be a wash to swap it out for 120VAC powered illumra single-channel room controllers, as they draw about 1 watt each. If I had single switches rather than three in one spot, then the power savings of the single-channel illumra receivers would be more compelling, compared to watt stoppers and the 3-channel room controller. Maybe I'll try out a one-channel unit somewhere else in the house.

Thursday, October 16, 2008

Introduction

Green Solutions - Why should you care?

Full disclosure first: I work for a company making energy saving devices, so of course I'm interested in you saving energy, money, and everything else that goes along with it.

I'm writing this blog to share some of my thoughts on green technologies that I have purchased, designed, or thought about building. I'm sure I'll figure out some other interesting things to include later as well.
To answer the title question of this post, there are many angles to "green" technologies. A few of them, in intentionally random order, are:
  1. You want to do your part to "save the planet."
  2. You want to save money on your energy bills.
  3. You want everyone else to know you're trying to save the planet.
  4. You think it's cool to try out new things.
  5. Energy independence sounds nice in case there's a disaster (solar panels on your roof?).
  6. You don't think our way of life is sustainable (we'll run out of "stuff").
In future posts, I plan to discuss a lot of these points, but for now, I'm going to start with a few projects I have set up around my house.

First off, my three children are ages 9, 7, and 4, so while they're pretty well trained at turning off the lights, they forget to do so at least once a day.
I decided to set up one of the devices I worked on at the office to try to save a little energy. It's a "room controller" from illumra. It connects to Watt Stopper power packs to control the lights in the room.

I use a wireless switch, mounted on the wall, to turn on the lights, and a motion detector mounted in the opposite corner of the room. The motion detector connects to another room controller, which transmits the status of the motion detector back to the main room controller. If no motion is detected in the room for 15 minutes, the lights turn off. If you move during the 15 second period after the lights turn off, they will come back on.

I bought a batch of Honeywell motion detectors off of ebay for a good price, but I had to set them to the highest sensitivity (and I installed the non-"pet-immune" lenses) so even small motion will be detected. If I were building a security system, I probably wouldn't want the occupancy detection to be so sensitive, because it would cause false alarms, but in "vacancy" detection, it's better to err on the side of falsely detecting someone in the room, rather than the other way around.

I haven't calculated the energy savings, but the main light fixtures in the kitchen (there are two) each have 4 fluorescent tubes (high-efficiency T8) with electronic ballasts. That's about 256 watts, I guess, so if the sensors turn off the lights for an extra 1 hour a day, that's about 1.8 kWh of savings per week, or about 21 cents a week in electrical savings. If the other can lights are on, and perhaps the ceiling fan, too, the savings could exceed that. If I used incandescents the savings would be higher, too. That's not a very compelling savings by itself, though, even with the longer lifetime of the bulbs factored in. I guess in a commercial building or a warehouse, the savings could be a lot more.