With well-insulated houses and central heating as standard, I always grew up with heating the space as how you stay warm in the winter. A colleague once shared with me that where he'd lived, they thought of it as heating people, not spaces when looking to stay warm.

The heating people approach means rather than heating the air in the room, you focus on heating the person: warm clothes, hot drinks, baths, cosy furniture with high backs and sides that traps heat in, or furniture that is itself heated like the kotatsu or aga, and generally local heating where a small room or even part of a room may be warm while the rest may be cool — dividing screens are sometimes used.

This approach was common until relatively recently and also still is in countries where it was difficult to stay cool in the summer and houses weren't typically built to keep heat in.

Thanks to Peter Wyatt-Brandenburg for sharing with me many years ago.

Heating people, heating spaces

A rather clever way of capturing energy as vehicles slow down is to store the energy you'd use in braking as gravitational energy. This way of storing energy is used on a number of central London underground stations by constructing the stations at the top of a small hill in the track. Once built, the hump-back-station design has the handy effect of naturally slowing trains down as they approach a station and naturally accelerating them as they leave a station. Apparently, on London's Victoria line this saves 5% in energy and helps the trains run 9% faster.

You're not always going to be able to put a slope just where you need to slow down, unfortunately. However, it makes a ton of sense for pedestrian crossings where raising the crossing to the level of the payment means pedestrians don't have kerbs to negotiate and cars are naturally encouraged to slow down.

Victoria line data from Sustainable Energy without the Hot Air, by the late David JC MacKay

Hump-back stations

Back in 1865, a chap called William Stanley Jevons noted that while there had been a number of improvements in coal efficiency in steam engines and the like, instead of reducing consumption the effect was to increase consumption instead — Jevon's paradox.

While it’s not a surefire outcome, there are plenty of parallels like more efficient batteries leading to more overall battery use, washing machines leading to doing more washes rather than less time spent washing, or the ability to recycle some plastics leading to more overall plastic consumption.

This is sometimes known as the rebound effect.

Also see the fifth fuel: energy efficiency, and save some landfill.

Jevon’s Paradox

Translation: The energy efficiency of computers doubles roughly every 18 months.

In a new twist beyond Moore’s Law, which shows signs of reaching it’s limits, there’s Koomey’s Law. In his own words, the idea is:

“…at a fixed computing load, the amount of battery you need will fall by a factor of two every year and a half.”

Why does this matter? It means we can fit more more computing power into smaller and smaller devices. Which is much of the reason the phone in your pocket is probably more powerful than the EDVAC there in the chart.

Sketchplanations tagged with energy