final blog in a series of 5

There is still quite a bit of detective work to be done. A cursory look at our graphs shows we are using on average 40kWatts (the equivalent of 400, 100 Watt, light bulbs) during nights/weekends and about 120kWatts peak during normal business hours.

From the below graph we can see that during business hours something is causing large spikes. Since this only happens during typical work hours we could probably attribute this behavior to the power hungry tools in our awesome Models Shop, or maybe the elevator. The spikes are probably due to the inductive load introduced when a motor such as a saw or compressor is turned on.

The chart below is a display of power use over a ten day period. You can see the reduced power consumption over the weekends and holidays. I would gather that since there is a small amount of power consumption on Monday May 25th (Memorial Day) some Continuumites are workaholics!

What’s Next

Possible improvements
Migrate data server applications to a proper web server
Add multi client capabilities so we can host data from other users.
Tie in real time power cost metrics
Carbon footprint tie in
Tie in weather parameters such as outside temperature and humidity.

Contribute
If you find this design intriguing and would like to contribute in some way, or if you have any questions feel free to email me at mcosta@dcontinuum.com

Design Overview

The electricity monitoring system consists of two major components. The first component is the utility meter reading device, the second is the data server. The utility meter reader monitors electricity usage and sends the latest value to the data server via TCP/IP sockets. The data server stores this value and serves the historical data through custom Perl scripts for web page display or RSS feed.

Utility meter reading in the electrical closet.

Overview

The Elster A3 Alpha utility meter has a blinking box (called Kh in the manual) on the LCD display with a blink frequency proportional to the instantaneous power use (marked by A in the above image). Every time the box changes state, this indicates .9kWh have been used. This will be our method of monitoring instantaneous power use. 

 In short this is an Embedded Linux device centered upon a Freescale iMx21 processor. It optically reads power usage from the utility meter and feeds the latest power consumption data to the server through a custom TCP/IP socket.

 The main requirement for the meter reader was flexibility. Some other requirements are video input/output and Ethernet. As a result I decided to use an ARM based processor that could run embedded Linux. This would allow me to develop software in a flexible Linux setting using GNU libraries and I would have a greater array of compatible hardware peripherals should I need them. 

Freescale iMX

We have worked with Freescale iMX processors on a few previous projects before so I knew they would be sufficient for my needs.  The iMX21 micro has an Enhanced Multi-Media Acceleration (EMMA) peripheral built in which frees the ARM processor from some of the intensive video manipulation tasks. The M9328MX21ADS development board from Freescale comes with an Embedded Linux BSP making it a very attractive platform for its “out of the box” quality.  Plus Gerry Vahe the FAE at Freescale is an Embedded Linux buff and he is a great resource because if you have ever built an embedded Linux development environment you know it can be a headache at times!

Freescale M9328MX21ADS development board, some notable features: 

·     IMX21 Arm Processor

·      Video Camera

·     3.5″ TGT QVGA LCD module 

·        Ethernet Interface, RS232

·     Hardware based RS232 bootloader ensuring I can never “brick” my device. 

Freescale Linux BSP with LTIB

·     Powerful kernel containing drivers for hardware included with the ADS dev. board

·      Blob TCP/IP bootloader featuring NFS capabilities & RS232 shell terminal

·      Includes GNU arm compilers and libraries

·      Includes a large array of demonstration applications and utilities.

I especially like the flexibility of deleloping an embedded device using NFS (Network File System). With NFS I don’t need to flash the device with new firmware for each build, I just recompile and reboot the device. The bootloader is setup with the proper IPs to fetch the kernel and file system image from my Linux development machine.

Tune in next week for a description of the software.  

2 of a 5 part series

Option 1

There are many options to monitoring power use.  One such way is to attach inductive coils around the main power lines to monitor Voltage and Current.  There are lots of products on the market that can be used in a residential setting.  These products require direct access to the mains power lines, but our commercial electrical closet has a main circuit breaker indicating 4000 Amps.  There is no way we were going anywhere near that!  Since we did not want to professionally install any expensive equipment for this initial experimentation stage we opted not to go this route.

from Elster Alpha Plus manual

Option 2

The Elster utility meter has an ANSI C12 Infrared data port on the front (marked by B in the above image) offering the ability to read power measurements from the meter.  The hardware protocol is a simple RS232 like-Infrared serial protocol.  We initially considered using this data port to read data from the meter but upon talking to NStar about it they told us we were not permitted to attach anything to the meter itself as this would be a violation of the meter lease agreement.

Option 3

The Elster meter has a numerical LCD display of the total watt/hours accumulated by the meter over a finite period of time.  We considered implementing an Optical Character Recognition system that would read the values on the LCD with a webcam and convert that to power use.  Unfortunately the values seemed to only update on a daily basis.  We wanted at least up to the minute resolution so this method was out of the question.

Option 4

After some research on the Elster A3 Alpha utility meter I found that there is a blinking box on the LCD display that has a frequency proportional to the instantaneous power use (marked by A in the above image).  Every time the box changes state, this indicates .9kWh (kilo Watt hours) have been used.  Finally a feature we can work with!  We will watch the blinking box with a web cam on an embedded Linux device and determine the energy use by monitoring the blink rate.

Tune in next week where I discuss the electronics and software design.

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On a recent trip to Spain I had the pleasure of visiting Seville for a few days. It was even more vibrant than I recalled from my prior visit in 2000. Sitting at cafes I enjoyed the sounds of varied tongues surrounding me—Spanish, German, French, Dutch, some completely unrecognizable. I returned to the gardens and again admired the Mudejar architecture.  But, in the midst of this old city was a new variety of charm: bikes.

There were businessmen on bikes. College students on bikes. Moms, Dads, teens on bikes. Bikes, bikes, bikes.

Sevici, launched in April 2007, is Seville’s thriving public bike program. Taking the lead from other European cities such as Lyon, Paris, and London, the program was implemented to reduce environmental and noise pollution, lessen road traffic, and provide a convenient service to city residents. So far, so good.

The key to the success of Sevici and other thriving bike share programs: smart design.

Employing learnings from the failures and successes of other bike share programs, Sevici offers a service that fits into people’s lives as they are.  It not only makes life easier, it enhances people’s lives by replacing the chore of commuting with a pleasant, refreshing activity.

So. What makes it work?

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There has been enough buzz around the PVC problem in the last 10 years that many credit card holders are aware of it, and would prefer a cleaner alternative.

It’s hard to know how many credit cards are really out there, but if every household in the US (~100 million) has 10-20 cards that’s 1-2 billion cards just in the US (yeah, that’s a lot of cards), using 10 million pounds of PVC (about 0.01 lbs/card).

Enter PLA–Polylactide or polylactic acid resin. This stuff has been around a while, and sounds great…made from corn, it’s biodegradable, compostable and renewable so it should be pretty eco-friendly right?

Unfortunately, not really.

There is a down side, at least for the near future. PLA is pretty energy intensive (like corn-based ethanol…don’t get me started), and most of our corn is grown in states whose electricity is coming from coal-fired power plants. Add to that the fact that corn-based products are competing with a food source and it’s reason to pause. Plant-based polymers have to be part of our future, but there’s still work to do.

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If you are an “ecogeek” like me you might have noticed all the products, services, and research that revolve around monitoring one’s power usage in real time.  Among the first commercially available products was the PowerCost Monitor from BlueLine Innovations.  NStar (the local power utility here in Boston) offered these little gadgets to a few hundred customers at a discount after conclusive research showed that personal power usage dropped about 5-15% when monitored in real time.

Real time means that when you turn off a light bulb you can see your KilloWattHour number drop within seconds, allowing you to understand in dollars and cents how much energy a typical 100 watt light bulb consumes.  This is a win-win situation for all- save money, save power and reduce greenhouse gas emissions.

This trend has continued to evolve and DIYers have joined in the fun.  Electronics designers have submitted two product ideas to the Core77 Greener Gadgets design competition.   The first was a Do-It-Yourself power monitoring device made from typical household products similar to the Kill-A-Watt from P3.

A year ago monitoring your power use in real time was a novel idea, now we need to take this information off the simple LCD display and feed it into the web.  Enter the Tweet-A-Watt by Limor Fried.  The Tweet-A-Watt basically takes the concept of real time power monitoring and offers the information to you and the public and is accessible from anywhere.

This concept offers the ability to feed this information into social networking sites like Twitter or Facebook. You could also be monitoring your power usage constantly through your smart phone (i.e. iPhone or Android), or crunching numbers and graphing through Google’s Power Meter.

I would really like to see this real time information offered via open standard protocols to inspire applications for all internet ready devices like the Chumby or iPhone.  Since Google seems to be the first large organization to aggregate this information, I am looking to Google to establish the standard.

The Design Management Review’s current issue features a piece by our sustainability experts Grant Kristofek and Mark Bates. Colorblind, our extensive in-house research project on consumers and their perception and digestion of all things green, is the focus of the piece.

Download it here.

On December 30th we were visited by Bruce Biewald, a Continuum client and the President of Synapse Energy Economics of Cambridge. For the past thirty years Biewald has advised state agencies, consumer and environmental advocates, utilities and others on the production and consumption of energy. As the co-author of more than one hundred reports for several different state and environmental agencies, he is a highly-respected voice in the on-going discussion of energy consumption, sustainability and the future of power. Bruce presented his perspectives on the technical, economic and regulatory challenges for reducing greenhouse gas emissions to the thirty or so who gathered in our great room.

What I took away from Biewald’s visit was the idea that consumers can and should modify their behavior to consume less energy, but that sound policy and government regulation is needed to truly minimize the environmental impact of power generation. Current regulation models fail to provide adequate incentives for innovation within the power industry. For example, since carbon emissions are not currently regulated, proposed power plant plans rarely include future costs of carbon in their financial models, despite the existence of cost estimation models.

Surely, no one can predict the future of carbon costs with any more certainty than the price of oil. But, omitting carbon costs in financial plans can lead to misguided technology and poorly made capacity decisions. We need to provide better incentives, improve policy, upgrade older facilities, and accurately represent the financial and environmental impact of new facilities when assessing power generation technology.

While reading the Ask Umbra column on the Grist website I came across a cool graph that shows the rate of CO2 emissions per passenger mile for most of the common commuting options. Produced by Sightline, a think tank based in Seattle, the graph provides a visual representation of something that’s on a lot of people’s minds as they make their way to work every morning.It’s an uncomplicated way to look at an often overcomplicated issue: What is the most climate-friendly way for me to get to work?