This week's Friday Catch-Up takes a look at keeping buildings cool, "hybrid" houses, fighting pests with a biotech solution that works with nature, and tracking mobile phones.
Pre-Cooling that Works: Researchers have long known that cooling a building well below the desired temperature early in the day, then letting it warm up to above the desired temperature in the afternoon -- a process called "pre-cooling" -- can reduce electricity demands and actually keep a building cooler throughout the day compared to traditional thermostat control. The problem is, the "thermal mass" of small office buildings varies so widely that it's easy to get the pre-cooling wrong and actually increase power use. Now engineers at Purdue University, working with Lawrence Berkeley National Laboratory and funded by the California Energy Commission, have worked out a straightforward algorithm for effective and efficient pre-cooling.
"The idea is to set the thermostat at 70 degrees Fahrenheit for the morning hours, and then you start adjusting that temperature upwards with a maximum temperature of around 78 during the afternoon hours, " Braun said. "When the thermostat settings are adjusted in an optimal fashion, the result is a 25 percent to 30 percent reduction in peak electrical demand for air conditioning.
The team's research shows that building occupants can't feel a significant difference between 70 and 74 degrees in the early part of the day, or 74 and 78 degrees in the afternoon.
Question not addressed by the research, but of increasing relevance for many of us: could the same algorithm apply to homes occupied by telecommuters during the day?
(Via Roland Picquepaille)
"Hybrid" Houses: Like it or not -- and those of you who hanker for precision in language won't like it at all -- the word "hybrid" is starting to take on a meaning far larger than its direct denotation of a single unit mixing two or more disparate elements. For a growing popular audience, the word "hybrid" is starting to mean "environmentally-friendly yet practical." The latest example: "Going 'hybrid' with houses" in this week's Christian Science Monitor.
The article is actually pretty good, covering (in brief detail) the growth of incentives for energy efficiency, the Energy Star program, and the increasing interest in Zero-Energy Homes.
Like a hybrid, the ZEH, as it's called, "drives" and looks like a normal house. Flat, unobtrusive solar tiles cover the roof and augment power. Tankless heat-as-you-use water heaters and super efficient windows reduce demand. The result is a wash - "zero" net energy consumption once the house is built.
The article's content will be familiar to regular WorldChanging readers, but I'm struck by the use of "hybrid" as shorthand for technologies that increase energy efficiency but don't require a radical shift in one's lifestyle. Interestingly, this is one case where the proponents of an invisible move to efficiency and proponents of a total transformation can agree. Advocates for increased use of bicycles and public transit tend to dislike hybrids as faux environmentalism, because they don't go nearly far enough in reducing fossil fuel use; similarly, those who wish to see a greater revolution in how we live, from walkable neighborhoods to high-density communities, would be equally dismayed by "zero energy" exurban McMansions.
So readers, your turn: which will prove more beneficial? Widespread adoption of gradualist measures or slower adoption of more radical ideas?
Cries for Help: One of the most controversial applications of genetic modification biotechnology has been the introduction of pesticides into crop DNA. Bioengineering firms called it an environmental win because it could reduce the use of artificial pesticides in large-scale agriculture, but most environmentalists rallied against the unexamined long-term health effects of what amounts to a poison added to plants. Now bioscientists at Germany's Max Planck Institute have come up with a genetic modification that might be nearly as effective at killing pests, but would not involve any kind of poison: make the plants call for help.
Corn plants emit a cocktail of scents when they are attacked by certain pests, such as a caterpillar known as the Egyptian cotton leaf worm. Parasitic wasps use these plant scents to localize the caterpillar and deposit their eggs on it, so that their offspring can feed on the caterpillar. Soon after, the caterpillar dies and the plant is relieved from its attacker. In the case of corn, only one gene, TPS10, has to be activated to attract the parasitic wasps. [...] Since this mechanism is based only on a single gene, it might be useful for the development of crop plants with a better resistance to pests...
At least 15 species of plants are known to release scents after insect damage, thus attracting the enemies of their enemies. Scientists term this mechanism "indirect defence".
The researchers added the TPS10 gene to the Arabidopsis plant, and confirmed that the wasps homed in on the modified crop. The work also resulted in an unexpected discovery: the wasps don't go after the scent instinctively, but must be exposed both to the TPS10 scent and the caterpillar to make them associate the two. This suggests that wasps could be "trained" to go after a wider variety of pests when they detect the chemical signal.
Phone-Tracking: Creepy, cool or both? A company called World-Tracker offers a service allowing you to follow the location of any GSM phone in the UK (at least those on the most popular network providers). The phone's location is tracked by GPS, where available, and by triangulation of cellular towers. The result is then displayed on a GoogleMap mash-up page.
Privacy advocates will be somewhat mollified that the system firsts sends a text message to the trackee asking for an opt-in before showing his or her location. That's good for preventing you from tracking the whereabouts of someone you don't know, but less of a barrier for stalkers who may have temporary access to someone's phone. A text message every time someone tries to track you would be a better way to avoid surreptitious surveillance, as would a requirement for opt-in confirmations every so many days or weeks.
World-Tracker is now only available in the UK, but the company plans to expand soon to continental Europe and the United States.
I would love to be given a chance to think up a solution that someone wants. I think of things, but seldom do people put their money where there mouth is. Does anyone really want something out there?