Team Members: Dave Buckler, Evan Cernea, and Chris Salzano
For Professor Allison Lassiter’s class at the University of Pennsylvania School of Design, we developed a prototype of a current sensor to help people better understand their household energy usage.
The Problem
Most people use electricity in their homes without any sense of how much energy they are using on a day to day basis. According to the United Nations, urban areas currently account for over 67 percent of energy-consumption related global greenhouse gases. This amount is expected to rise to 74 percent by 2030. Household energy is often provided by forms of energy that contribute greenhouse gases to the environment and the Philadelphia area’s main power supplier, PECO, is no exception.
PECO estimates that the average household in Philadelphia uses 700 kilowatt hours per month. That is equivalent to driving 8,131 miles, using 373 gallons of gasoline, and requires 3.9 acres of forest to sequester the carbon emissions. As the world becomes more urban and carbon sinks disappear, it is imperative that we take steps to actively reduce our power usage.
There are legal imperatives for PECO to reduce its customers’ power consumption. The 2008 Pennsylvania state law Act 129 states that PECO (along with all other energy suppliers in Pennsylvania) must reduce its overall usage by two million megawatt hours, and reduce peak energy usage by 161 megawatts by 2021. Targeted interventions to increase customer awareness of their power consumption may help PECO reach these goals.
The Solution: PowerDown Challenge Kit
We have developed the PowerDown Challenge Kit to provides real time tracking and benchmarking of household power usage.
This product uses non-invasive current sensors to read electrical current in amps into Arduino. Then, the Arduino displays the following information on an LCD screen:
- Current Amperage Use
- Current Power Use in Watts
- Past Hour Power Use
The information collected from the current sensor is transmitted via Bluetooth to another Arduino board with an RGB LED “candle,” which changes color based on instanteous power usage compared to a preset threshold of desired hourly usage. Low usage makes the candle turn green; moderate usage makes it yellow; high usage makes it red.
Here is a diagram of where the non-invasive current sensor clips onto the feed line of the house’s power system. The non-invasive current sensor is physically connected to the LCD screen:
Below is a representation of the candle existing in a living room, providing visual feed back to the household about usage:
This is a live demonstration of the product, using a space heater’s power usage as an analog for an entire house:
We believe that this product will work for several reasons. First, it is visually appealing and helps everyone in a household understand energy usage, not just the person who pays the bill. Second, it helps provide a social norming effect which is well studied in behavior economics and has been shown to decrease electricity usage in Philadelphia. When customers were informed of their monthly energy usage compared to similar households, they reduced overall power usage by two percent. Lastly, we know that this product is easily scalable to incorporate additional components and friendly competition with neighbors.
Future Directions
As we move forward with the prototype, we are working to add additional functionality to the system. First, we want to upload the collected usage information to a server, potentiallyhoused at PECO headquarters, to facilitate adding additional LED feedback to compare household power consumption to similar households in the neighborhood. This will require incorporation of WiFi breakout boards and establishing local servers points. Second, we want to move away from Bluetooth communication in favor of radio frequency transmission and integration with smart home systems. Once integrated with existing smart home systems the functions as an add-on rather than a standalone device. Lastly, we want to mimic the Sense home energy monitor model, which separates what power is always on (like the fridge) versus variably on electricity uses (like overhead lights). We will need to create a calibration protocol within the product’s code so we can see day-to-day how much power is being used by the house to best estimate how much power usage is the initial baseline.
We also have thought about selling this product. The component parts to make this prototype cost about $75, and we imagine that the price could be further reduced if items were bought in bulk. We do envision that this could be a consumer product that could be easily addable to any home. But we also envision developing a partnership with PECO and the City of Philadelphia’s Energy Authority to help meet some of their goals.
The Philadelphia Energy Authority’s main campaign leverages $1 billion in public and private investment to create a more sustainable energy future with a specific focus on low- to moderate-income houses and public schools. We envision partnering with PECO and the Philadelphia Housing Authority to place these devices in public housing and schools to understand power usage and areas for reduction.. With additional benchmarking capabilities we can understand what power is always being used andwe can help the City target blocks and neighborhoods with high utilization for reduction efforts. In schools, we can identify energy-inefficient appliances, increase student and teacher awareness of power consumption and foster friendly competition across the school district to reduce power consumption per student.
Below is the product diagram including future directions:
With the PowerDown Challenge Kit, we hope to inspire individual behavioral modification to change the world for the better.