Buildings Waste Half Their Energy Heating Empty Air

2021-12-04 original Science

DRAWDOWN — 100 Ways to Reverse Global Warming

“Drawdown” is a project-style book led by an American writer, with contributions from researchers around the world. It lays out what can be done to achieve “drawdown—the point at which carbon dioxide levels begin to decline”—divided broadly into a survey of what is already being done and an introduction to future technologies. The “understanding of the current state” section in particular shocked me personally, since it was full of items whose details I didn’t know, or wasn’t even aware of at all. It’s fair to call this a must-read for working professionals. At over 400 pages in a two-column format, though, its actual volume is easily three ordinary books’ worth, and even for me, a fairly fast reader, it took more than a month to finish.

So I’d like to extract and organize the essence of it to some degree. In any case, this is a book perfectly suited to grasping the “big picture.”

Here I’ll cover the construction and urban sector.

An estimated 25-60% of heating and cooling leaks out to the outside air, an enormous waste. Building energy efficiency can also be improved by 10-20% through IoT optimization, but energy expenditure tends to be small relative to overall spending, so there isn’t sufficient motivation for capital investment. That’s speaking purely in terms of money.

Net Zero Energy Houses

Buildings whose total energy balance is zero. Dimming windows, verandas designed to project outward in winter and provide shade in summer, air-cooling systems inspired by termite mounds and geothermal heat, enhanced ceiling insulation to keep interiors warm in winter and cool in summer, solar panels for power generation, and lighting designed to make effective use of sunlight.

Kaupuni Village in Hawaii
The Sonnenschiff solar city in Freiburg

More and more states are enacting laws that prohibit the construction of any building other than a net zero energy house.

Rocky Mountain Institute

Basalt, Colorado Comfort is determined by temperature, humidity, wind speed, clothing level, activity level, and surrounding surface temperature. Controlling these factors has expanded the range in which people feel comfortable, from the conventional 21-24°C to 19-28°C.

Green Roofs

Stuttgart in Germany, Linz in Austria, and others. Seen from the sky, it’s a sea of green. Roofs promote the heat island effect, so covering them with greenery counters that. Ground cover (low-growing plants that spread to cover the surface) suits rooftops because it grows in shallow soil. Sedums, stonecrops, and the like.

Switzerland’s Kantonsspital Basel had the world’s first green roof, in 1990. In Singapore, the government subsidizes half the cost of green roofs.

Cool Roofs

Reflective roofs. Low cost, easy to maintain. Increasing in California. But they’re glaring, a nuisance to neighbors, and cold in winter. Reflectivity-adjusting technology is being developed.

Heat Pumps

A heat-transfer technology that can send outside heat inward in winter and inside heat outward in summer. In northern Japan, geothermal heat is used to warm homes. The problem is that retrofitting is difficult and costly.

DHC: District Heating and Cooling Chilled and hot water pipes cool or heat a whole cluster of buildings together. Its origins trace to Roman hot water systems, and it was revived in New York in the 19th century.

Copenhagen, Denmark, leads the world in DHC. Waste heat from thermal power plants covers 98% of heating needs, and thermal power is set to be fully converted to biomass as well. In summer, seawater from the Øresund Strait is used for cooling.

Walkable Cities

Examples include Florence, Marrakech, Dubrovnik, and Buenos Aires. These don’t rely on appeals to convenience. Walking needs to be beneficial, safe, comfortable, and interesting. A key condition is good connections to multiple forms of public transit.

Cities of Bicycles

Amsterdam, Rotterdam, Utrecht, and others. Denmark, Germany, and the Netherlands have strong bicycle infrastructure. In Denmark, 18% of trips are by bicycle. In the Netherlands, 27%. In the US, 1%.

Copenhagen has installed bicycle superhighways. It deliberately reduces parking space to make driving less convenient.

Green Wave: an innovation whereby cyclists riding at a constant speed avoid hitting red lights.

Glass

Glass reduces a home’s insulation performance, but laminated glass, low-emissivity coatings, and other measures have improved this. In the US, this falls under the Energy Star regulatory program.

Electrochromism: glass that changes color with electricity. There’s also thermochromism and photochromism. Letting visible light through while blocking heat is also a recent technology. The Boeing 787, 788, and 789 use electrochromic glass, also called smart windows. Adoption stands at a mere 0.004%.

Landfill Gas Capture

Holes are drilled into landfills and pipes laid to collect the gas, which is then safely vented, burned, or compressed and blended into natural gas for use. Aerobic bacteria first break down organic matter in landfills. But as layers pile up, anaerobic bacteria take over, producing a gas that is roughly half carbon dioxide and half methane. Carbon dioxide returns to the natural cycle, but methane is different. The problem is that already-closed landfills capture methane more efficiently, yet 90% of methane emissions come from landfills still actively receiving waste. Also, landfill methane capture is a technology that becomes unnecessary once landfilling itself disappears.

Water Leaks

Water leaks occur constantly around the world (in the US, 1/6 of water is lost), wasting the energy used to produce that water. So simply overhauling water pipe infrastructure can reduce greenhouse gases.

【New Technologies and New Initiatives】

LBC: Living Building Challenge

This is essentially a certification, but it has several unusual rules.

Do not use undeveloped land
Grow food on the property
For every acre built, conserve one acre of nature
Design for a life lived on foot or by bicycle
Net-positive water
Net-positive energy
No Red List materials
Offset the carbon used during construction
Source materials locally
Reuse over 90% of construction waste
Donate half of the investment amount to social causes

Examples include the Brock Environmental Center in Virginia.

Wood Construction

Wood construction can sequester carbon for long periods. Pioneering all-wood buildings include a 14-story apartment building in Bergen, Norway, a 10-story building in Melbourne, and a 9-story building in London.

Laminating thin boards together as a substitute for steel or concrete has been done for nearly two hundred years. Steel bends under heat, but wood panels char on the surface, protecting the interior.

Tall Wood Building Prize: many building codes limit wood construction to 4 or 5 stories.

Originally published in Japanese at https://clazytech.com/2021/12/822/. Translated with LLM assistance and reviewed before publication.