Among the cardinal rules for designing (or re-designing) energy efficiency into buildings is to consider how the space is used by its occupants. If designed correctly, interior spaces induce people to make more efficient choices, such as using reduced light or water to attain the desired level of comfort.
The beauty of the built environment is that when people’s habits cannot be modified or when design is not conducive to efficient use of resources, the space can simply be re-designed. Sometimes very minor changes can make dramatic impacts.
My master bathroom is case-in-point. The toilet resides in a little closet separate from the rest of the bathroom. My routine for the past 6 months involves turning on that closet light first thing in the morning. As I complete my preparation and grooming for work, I sometimes become rushed to get out of the house, and occasionally that light is left on. Arriving home from work 10 hours later, I enter the bathroom only to discover the toilet closet light has been blazing away all day, wasting energy.
The Intermatic switch uses no electricity, and it functions via a mechanical timer. I selected this brand and configuration because it is designed to replace standard wall switches, and it fits into a conventional junction box. Replacing the ON-OFF switch with a timer was easy, and any do-it-yourselfer can make the swap with just a flat-head screw driver (provided the power is shut off at the breaker before beginning the work).
As I am trying to teach my energy engineering students at UNT, no energy retrofit should be undertaken unless it makes economic sense. So, how much energy did this little switch replacement save, and how long will it take to pay back?
I estimate that I leave the offending light on at least once per week for a duration of 10 hours per incident, and I am out of the house about 50 weeks per year. I recently swapped the toilet closet incandescent for a 23-watt compact fluorescent (see my post “Let the Residential Lighting Retrofit Commence!” for details). So, crunching the numbers yields 11.5 kW-hours per year of wasted energy. I pay roughly $0.131 per kilowatt-hour; thus, leaving the light burning costs me about $1.51 per year. The simple payback period for a $17.99 timing switch is just under 12 years.
As energy retrofits go, a 12-year payback is not stellar. Solar panels or new roof insulation should pay back about twice as fast. However, the project took me less than an hour to complete, and for about the cost of a pizza, I don’t have to come home once a week to realize I left the lights on anymore.
In this new Design News feature, "How it Works," we’re starting off by examining the inner workings of the electronic cigarette. While e-cigarettes seemed like a gimmick just two or three years ago, they’re catching fire -- so to speak. Sales topped $1 billion last year and are set to hit $10 billion by 2017. Cigarette companies are fighting back by buying up e-cigarette manufacturers.
Advertised as the "Most Powerful Tablet Under $100," the Kindle Fire HD 6 was too tempting for the team at iFixit to pass up. Join us to find out if inexpensive means cheap, irreparable, or just down right economical. It's teardown time!
The increased adoption of wireless technology for mission-critical applications has revved up the global market for dynamic electronic general purpose (GP) test equipment. As the link between cloud networks and devices -- smartphones, tablets, and notebooks -- results in more complex devices under test, the demand for radio frequency test equipment is starting to intensify.
Much of the research on lithium-ion batteries is focused on how to make the batteries charge more quickly and last longer than they currently do, work that would significantly improve the experience of mobile device users, as well EV and hybrid car drivers. Researchers in Singapore have come up with what seems like the best solution so far -- a battery that can recharge itself in mere minutes and has a potential lifespan of 20 years.
Some humanoid walking robots are also good at running, balancing, and coordinated movements in group settings. Several of our sports robots have won regional or worldwide acclaim in the RoboCup soccer World Cup, or FIRST Robotics competitions. Others include the world's first hockey-playing robot and a trash-talking Scrabble player.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.